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Roles of membrane trafficking in plant cell wall dynamics. The cell wall is one of the characteristic components of plant cells. The cell wall composition differs among cell types and is modified in response to various environmental conditions. To properly generate and modify the cell wallmany proteins are transported to the plasma membrane or extracellular space through membrane trafficking, which is one of the key protein transport mechanisms in eukaryotic cells.

Given the diverse composition and functions of the cell wall in plants, the transport of the cell wall components and proteins that are involved in cell wall -related events could be specialized for each cell type, i.

In this review, we summarize the recent progress in the current understanding of the roles and mechanisms of membrane trafficking in plant cells and focus on the biogenesis and regulation of the cell wall.

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Plant cells rely on their cell walls for directed growth and environmental adaptation. Synthesis and remodelling of the cell walls are membrane -related processes. This exchange of material and the localization of cell wall proteins at certain spots in the plasma membrane seem to rely on a particular membrane composition. In addition, sensors at the plasma membrane detect changes in the cell wall architecture, and activate cytoplasmic signalling schemes and ultimately cell wall remodelling.

The apoplastic polysaccharide matrix is, on the other hand, crucial for preventing proteins diffusing uncontrollably in the membrane. Therefore, the cell wall -plasma membrane link is essential for plant development and responses to external stimuli.

This review focuses on the relationship between the cell wall and plasma membraneand its importance for plant tissue organization. For permissions, please email: Membrane-wall attachments in plasmolysed plant cells. Field emission scanning electron microscopy of plasmolysed Tradescantia virginiana leaf epidermal cells gave novel insights into the three-dimensional architecture of Hechtian strands, Hechtian reticulum, and the inner surface of the cell wall without the need for extraction. At high magnification, we observed fibres that pin the plasma membrane to the cell wall after plasmolysis.

Treatment with cellulase caused these connecting fibres to be lost and the pinned out plasma membrane of the Hechtian reticulum to disintegrate into vesicles with diameters of nm. This suggests that the fibres may be cellulose. After 4 h of plasmolysis, a fibrous meshwork that labelled with anti-callose antibodies was observed within the space between the plasmolysed protoplast and the cell wall by field emission scanning electron microscopy.

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Interestingly, macerase-pectinase treatment resulted in the loss of this meshwork, suggesting that it was stabilised by pectins. We suggest that cellulose microfibrils extending from strands of the Hechtian reticulum and entwining into the cell wall matrix act as anchors for the plasma membrane as it moves away from the wall during plasmolysis.

Synthesis of cell wall xylans and glucans by golgi membranes. The Golgi apparatus was enriched from plasma membrane and other organelles by flotation density gradient centrifugation.

Glucan synthase I and II, which are established markers for Golgi and plasma membranerespectively, displayed considerable overlap in conventional separations with sucrose density gradients. We also have developed techniques of gas-liquid chromatography and radiogas proportional counting to achieve capillary quality separation of partially methylated alditol acetates with simultaneous determination of radioactivity in the derivatives.

Digestion of polymeric products by specific endo-glycanohydrolases to diagnostic oligosaccharides also reveal specific kinds of polysaccharides synthesized by the Golgi membranes. A combination of these techniques provides unequivocal determination of the linkage structure of specific polymers synthesized by the purified Golgi apparatus.

Protein diffusion in plant cell plasma membranes: Studying protein diffusion informs us about how proteins interact with their environment.

Work on protein diffusion over the last several decades has illustrated the complex nature of biological lipid bilayers. The plasma membrane contains an array of membrane -spanning proteins or proteins with peripheral membrane associations. Maintenance of plasma membrane microstructure can be via physical features that provide intrinsic ordering such as lipid microdomains, or from membrane -associated structures such as the cytoskeleton. Recent evidence indicates, that in the case of plant cellsthe cell wall seems to be a major player in maintaining plasma membrane microstructure.

Characterisation of cell-wall polysaccharides from mandarin segment membranes. In an attempt to develop a process of enzymatic peeling of mandarin segments suitable for use on an industrial scale, the cell wall fraction of the segment membrane of Satsuma mandarin fruits was extracted to obtain a chelating agent-soluble pectin fraction ChSSa dilute sodium hydroxide-soluble pectin fraction DASSa 1M sodium hydroxide-soluble hemicellulose fraction 1MASSa 4M sodium hydroxide-soluble hemicellulose fraction 4MASS and a cellulose-rich residue 3.

The ChSS pectin consisted mainly of galacturonic acid followed by arabinose and galactose. Eighty-nine percent of the galacturonic acid present in the segment membranes was recovered in the above two pectin fractions.

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The ferric siderophores were dissolved in a small volume of water, to which excess recrystallized 8-hydroxyquinoline was added. Iron is an important element for most microorganisms owing to its importance in biogeochemical reactions including respiration, photosynthetic transport, nitrate synthesis, nitrogen fixation and detoxification of oxygen radicals.

The two hemicellulosic fractions consisted of two different molecular weight populations, which also differed in their sugar composition. Arabinose, xylose, mannose, galactose and glucose were the main sugar constituents of these hemicellulose fractions.

In addition to an arabino xylan and a xyloglucan, the presence of an arabinogalactan is suggested by the sugar composition of both hemicelluloses. The pectin fractions were also characterised by their degradability by the pectic enzymes polygalacturonase, pectinmethylesterase and rhamnogalacturonan hydrolase.

However the degree of degradation of the pectin fractions by enzymes differed, and the amount of the polymeric materials resistant to further degradation and the oligomeric products also differed.

Using pectic enzymes it is possible to obtain peeled mandarin segments ready to eat or for canning. Plant cell wall secretion and lipid traffic at membrane contact sites of the cell cortex.

Plant cell wall secretion is the result of dynamic vesicle fusion events at the plasma membrane. The importance of the lipid bilayer environment of the plasma membrane and its interactions with the endomembrane system through vesicle traffic are well recognized. Recent advances in yeast molecular biology and biochemistry lead us to re-examine the hypothesis that non-vesicular traffic of lipids through close contact sites of the plasma membrane and endoplasmic reticulum could also be important in plant cell wall biosynthesis.

Non-vesicular traffic is the extraction and transfer of individual lipid molecules from a donor bilayer to a target bilayer, usually with the assistance of lipid transfer proteins. The connection of cytoskeletal network with plasma membrane and the cell wall.

The cell wall provides external support of the plant cellswhile the cytoskeletons including the microtubules and the actin filaments constitute an internal framework. The cytoskeletons contribute to the cell wall biosynthesis by spatially and temporarily regulating the transportation and deposition of cell wall components. This tight control is achieved by the dynamic behavior of the cytoskeletons, but also through the tethering of these structures to the plasma membrane.

This tethering may also Nye casino siderophores aspergillus penicillium removal beyond the plasma membrane and impact on the cell wallpossibly in the form of a feedback loop.

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We also discuss the prospective roles of these components in cell wall biosynthesis and modifications, and aim to provide a platform for further studies in this field.

Vesicles between plasma membrane and cell wall prior to visible senescence of Iris and Dendrobium flowers. Cut Iris flowers Iris x hollandica, cv. Blue Magic show visible senescence about two days after full opening. Epidermal cells of the outer tepals collapse due to programmed cell death PCD. Transmission electron microscopy TEM showed irregular swelling of the cell wallsstarting prior to cell collapse.

Compared to cells in flowers that had just opened, wall thickness increased up to tenfold prior to cell death. Fibrils were visible in the swollen walls.

After cell death very little of the cell wall remained. Prior to and during visible wall swelling, vesicles paramural bodies were observed between the plasma membrane and the cell walls. The vesicles were also found in groups and were accompanied by amorphous substance.

They usually showed a single membraneand had a variety of diameters and electron densities. Cut Dendrobium hybrid cv. Lucky Duan flowers exhibited visible senescence about 14 days after full flower opening.

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Paramural bodies were also found in Dendrobium tepal epidermis and mesophyll cellsrelated to wall swelling and degradation. Although alternative explanations are well possible, it is hypothesized that paramural bodies carry enzymes involved in cell wall breakdown.

Cell wall polysaccharide biosynthesis by membrane fragments from Streptococcus pyogenes and stabilized L-form. The formation and composition of a cell wall rhamnose-containing polysaccharide by membrane fragments from Streptococcus pyogenes and its stabilized L-form were compared. Also, the effect of prior treatment on the ability of coccal whole- cell and membrane fragments to incorporate radioactivity from thymidine diphosphate- 14 C-rhamnose, and the results of subsequent attempts to remove labeled polysaccharide from such membranes are given.

However, once bound, both membrane fragments polymerized rhamnose to the same extent. These findings tend to negate the almost complete lack of polymeric rhamnose within the intact L-form as being due to the absence of membrane enzymes necessary for the transfer of rhamnose from a suitable precursor Casino spil paa nettetal deutschland flagge kaufen verkaufen membrane acceptor sites or enzymes responsible for rhamnose polymerization.

Degradation of labeled rhamnose polysaccharide after isolation from coccal membranes by mild acid hydrolysis showed muramic acid and glucosamine to be attached. This same polysaccharide from L-form membrane fragments was devoid of amino sugars.

These data suggest the possible involvement of amino sugars in the attachment of cell wall polymeric rhamnose to the streptococcal cytoplasmic membrane.

The absence of attached amino sugars to rhamnose polysaccharide from L-form membrane fragments is discussed in terms of this organism's continued inability for new cell wall formation. The isolation, from streptococcal membrane fragments, of a polysaccharide containing rhamnose and amino sugars common to at least two different streptococcal cell wall -type polymers was demonstrated.

S-layer and cytoplasmic membrane - exceptions from the typical archaeal cell wall with a focus on double membranes. Nye casino siderophores aspergillus penicillium removal common idea of typical cell wall architecture in archaea consists of a pseudo-crystalline proteinaceous surface layer S-layersituated upon the cytoplasmic membrane.

This is true for the majority of described archaea, hitherto. Within the crenarchaea, the S-layer often represents the only cell wall component, but there are various exceptions from this wall architecture. Beside glycosylated S-layers in hyper thermophilic cren- and euryarchaea as well as halophilic archaea, one can find a great variety of other cell wall structures like proteoglycan-like S-layers Halobacteriaglutaminylglycan Natronococcimethanochondroitin Methanosarcina or double layered cell walls with pseudomurein Methanothermus and Methanopyrus.

The presence of an outermost cellular membrane in the crenarchaeal species Ignicoccus hospitalis already gave indications for an outer membrane similar to Gram-negative bacteria. Although there is just limited data concerning their biochemistry and ultrastructure, recent studies on the euryarchaeal methanogen Methanomassiliicoccus luminyensis, cells of the ARMAN group, and the SM1 euryarchaeon delivered further examples for this exceptional cell envelope type consisting of two membranes.

S-layer and cytoplasmic membrane — exceptions from the typical archaeal cell wall with a focus on double membranes. Plasma membrane microdomains from hybrid aspen cells are involved in cell wall polysaccharide biosynthesis. Detergent-resistant plasma membrane microdomains [DRMs detergent-resistant membranes ] were isolated recently from several plant species. As for animal cellsa large range of cellular functions, such as signal transduction, endocytosis and protein trafficking, have been attributed to plant lipid rafts and DRMs.

The data available are essentially based on proteomics and more approaches need to be undertaken to elucidate the precise function of individual populations of DRMs in plants. We report here the first isolation of DRMs from purified plasma membranes of a tree species, the hybrid aspen Populus tremula x tremuloides, and their biochemical characterization.

Plasma membranes were solubilized with Triton X and the resulting DRMs were isolated by flotation in sucrose density gradients. The DRMs were enriched in sterols, sphingolipids and glycosylphosphatidylinositol-anchored proteins and thus exhibited similar properties to DRMs from other species.

The association of these enzymes with DRMs was demonstrated using specific glucan synthase assays and antibodies, as well as biochemical and chemical approaches for the characterization of the polysaccharides synthesized in vitro by the isolated DRMs. In addition to shedding Nye casino siderophores aspergillus penicillium removal on the lipid environment of callose and cellulose synthases, our results demonstrate the involvement of DRMs in the biosynthesis of important cell wall polysaccharides.

This novel concept suggests a function of plant membrane microdomains in cell growth and morphogenesis.

Fungal cell walls and cell membranes are the main targets of antifungals.

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Although alternative explanations are well possible, it is hypothesized that paramural bodies carry enzymes involved in cell wall breakdown. Cell wall polysaccharide biosynthesis by membrane fragments from Streptococcus pyogenes and stabilized L-form.

The formation and composition of a cell wall rhamnose-containing polysaccharide by membrane fragments from Streptococcus pyogenes and its stabilized L-form were compared. Also, the effect of prior treatment on the ability of coccal whole- cell and membrane fragments to incorporate radioactivity from thymidine diphosphate- 14 C-rhamnose, and the results of subsequent attempts to remove labeled polysaccharide from such membranes are given.

However, once bound, both membrane fragments polymerized rhamnose to the same extent. These findings tend to negate the almost complete lack of polymeric rhamnose within the intact L-form as being due to the absence of membrane enzymes necessary for the transfer of rhamnose from a suitable precursor to membrane acceptor sites or enzymes responsible for rhamnose polymerization.

Degradation of labeled rhamnose polysaccharide after isolation from coccal membranes by mild acid hydrolysis showed muramic acid and glucosamine to be attached. This same polysaccharide from L-form membrane fragments was devoid of amino sugars. These data suggest the possible involvement of amino sugars in the attachment of cell wall polymeric rhamnose to the streptococcal cytoplasmic membrane. The absence of attached amino sugars to rhamnose polysaccharide from L-form membrane fragments is discussed in terms of this organism's continued inability for new cell wall formation.

The isolation, from streptococcal membrane fragments, of a polysaccharide containing rhamnose and amino sugars common to at least two different streptococcal cell wall -type polymers was demonstrated. S-layer and cytoplasmic membrane - exceptions from the typical archaeal cell wall with a focus on double membranes.

The common idea of typical cell wall architecture in archaea consists of a pseudo-crystalline proteinaceous surface layer S-layer , situated upon the cytoplasmic membrane.

This is true for the majority of described archaea, hitherto. Within the crenarchaea, the S-layer often represents the only cell wall component, but there are various exceptions from this wall architecture.

Beside glycosylated S-layers in hyper thermophilic cren- and euryarchaea as well as halophilic archaea, one can find a great variety of other cell wall structures like proteoglycan-like S-layers Halobacteria , glutaminylglycan Natronococci , methanochondroitin Methanosarcina or double layered cell walls with pseudomurein Methanothermus and Methanopyrus. The presence of an outermost cellular membrane in the crenarchaeal species Ignicoccus hospitalis already gave indications for an outer membrane similar to Gram-negative bacteria.

Although there is just limited data concerning their biochemistry and ultrastructure, recent studies on the euryarchaeal methanogen Methanomassiliicoccus luminyensis, cells of the ARMAN group, and the SM1 euryarchaeon delivered further examples for this exceptional cell envelope type consisting of two membranes. S-layer and cytoplasmic membrane — exceptions from the typical archaeal cell wall with a focus on double membranes.

Plasma membrane microdomains from hybrid aspen cells are involved in cell wall polysaccharide biosynthesis. Detergent-resistant plasma membrane microdomains [DRMs detergent-resistant membranes ] were isolated recently from several plant species. As for animal cells , a large range of cellular functions, such as signal transduction, endocytosis and protein trafficking, have been attributed to plant lipid rafts and DRMs.

The data available are essentially based on proteomics and more approaches need to be undertaken to elucidate the precise function of individual populations of DRMs in plants.

We report here the first isolation of DRMs from purified plasma membranes of a tree species, the hybrid aspen Populus tremula x tremuloides, and their biochemical characterization. Plasma membranes were solubilized with Triton X and the resulting DRMs were isolated by flotation in sucrose density gradients. The DRMs were enriched in sterols, sphingolipids and glycosylphosphatidylinositol-anchored proteins and thus exhibited similar properties to DRMs from other species.

The association of these enzymes with DRMs was demonstrated using specific glucan synthase assays and antibodies, as well as biochemical and chemical approaches for the characterization of the polysaccharides synthesized in vitro by the isolated DRMs. In addition to shedding light on the lipid environment of callose and cellulose synthases, our results demonstrate the involvement of DRMs in the biosynthesis of important cell wall polysaccharides. This novel concept suggests a function of plant membrane microdomains in cell growth and morphogenesis.

Fungal cell walls and cell membranes are the main targets of antifungals. In this study, we report on the antifungal activity of an ethanol extract from Paeonia lactiflora against Candida albicans, showing that the antifungal activity is associated with the synergistic actions of preventing cell wall synthesis, enabling membrane depolarization, and compromising permeability.

First, it was shown that the ethanol extract from P. In isotonic media, cell bursts of C. Second, the ethanol extract from P. Membrane depolarization manifested as increased fluorescence intensity by staining P. Membrane permeability was assessed by crystal violet assay, and C. The findings suggest that P. AT14A mediates the cell wall -plasma membrane -cytoskeleton continuum in Arabidopsis thaliana cells.

AT14A has a small domain that has sequence similarities to integrins from animals. Integrins serve as a transmembrane linker between the extracellular matrix and the cytoskeleton, which play critical roles in a variety of biological processes.

Because the function of AT14A is unknown, Arabidopsis thaliana AT14A, which is a transmembrane receptor for cell adhesion molecules and a middle member of the cell wall -plasma membrane -cytoskeleton continuum in plants, has been described.

AT14A, co-expressed with green fluorescent protein GFP , was found to localize mainly to the plasma membrane. The mutant Arabidopsis at14a-1 cells exhibit various phenotypes with cell shape, cell cluster size, thickness, and cellulose content of cell wall , the adhesion between cells , and the adhesion of plasma membrane to cell wall varied by plasmolysis. Using direct staining of filamentous actin and indirect immunofluorescence staining of microtubules, cortical actin filaments and microtubules arrays were significantly altered in cells , either where AT14A was absent or over-expressed.

It is concluded that AT14A may be a substantial middle member of the cell wall -plasma membrane -cytoskeleton continuum and play an important role in the continuum by regulating cell wall and cortical cytoskeleton organization. These sensory cells use a membrane protein, Slc26a5 prestin , to generate mechanical force at high frequencies, which is essential for explaining the exquisite hearing sensitivity of mammalian ears.

Previous studies suggest that Slc26a5 continuously diffuses within the membrane , but how can a freely moving motor protein effectively convey forces critical for hearing? These mice and four other strains expressing fluorescently labeled membrane proteins were used to examine their lateral diffusion in the OHC lateral wall. All five proteins showed minimal diffusion, but did move after pharmacological disruption of membrane -associated structures with a cholesterol-depleting agent and salicylate.

The structural constraint of membrane proteins may exemplify convergent evolution of cellular motors across species. Our findings also suggest a possible mechanism for disorders of cholesterol metabolism with hearing loss such as Niemann-Pick Type C diseases. Mechanics of membrane bulging during cell-wall disruption in Gram-negative bacteria.

The bacterial cell wall is a network of sugar strands crosslinked by peptides that serve as the primary structure for bearing osmotic stress. Despite its importance in cellular survival, the robustness of the cell wall to network defects has been relatively unexplored. Treatment of the Gram-negative bacterium Escherichia coli with the antibiotic vancomycin, which disrupts the crosslinking of new material during growth, leads to the development of pronounced bulges and eventually of cell lysis.

Here, we model the mechanics of the bulging of the cytoplasmic membrane through pores in the cell wall. This critical pore size is large compared to the typical distance between neighboring peptides and glycan strands, and hence pore size acts as a constraint on network integrity.

We also discuss the general implications of our model to membrane deformations in eukaryotic blebbing and vesiculation in red blood cells. Endocytic pathways involved in PLGA nanoparticle uptake by grapevine cells and role of cell wall and membrane in size selection. Clathrin-independent endocytosis is the main internalization route. The cell wall plays a more prominent role than the plasma membrane in NPs' size selection. In the last years, many studies on absorption and cell uptake of nanoparticles by plants have been conducted, but the understanding of the internalization mechanisms is still largely unknown.

In this study, polydispersed and monodispersed poly lactic-co-glycolic acid nanoparticles PLGA NPs were synthesized, and a strategy combining the use of transmission electron microscopy TEM , confocal analysis, fluorescently labeled PLGA NPs, a probe for endocytic vesicles FM , and endocytosis inhibitors i. A strong adhesion of PLGA NPs to the outer side of the cell wall was observed, presumably due to electrostatic interactions.

Confocal microscopy and treatment with endocytosis inhibitors suggested the involvement of both clathrin-dependent and clathrin-independent endocytosis in cell uptake of PLGA NPs and the latter appeared to be the main internalization pathway. Experiments on grapevine protoplasts revealed that the cell wall plays a more prominent role than the plasma membrane in size selection of PLGA NPs.

Cell wall and membrane changes associated with ethambutol resistance in Mycobacterium tuberculosis H37Ra. Biochemical variations accompanying the acquisition of ethambutol EMB resistance in a single-step mutant of Mycobacterium tuberculosis H37Ra were analyzed. Comparative analysis of phospholipids revealed a reduced content in the EMB-resistant strain, particularly in the cell membrane fraction.

Significant alterations were observed in the individual phospholipid content and phospholipid fatty acyl group composition of whole cells and subcellular fractions. Quantitative changes were seen in the chemical constituents of the cell walls of resistant cultures in comparison with those of EMB-susceptible cultures of M.

Alterations in the binding of 1-anilinonaphthalenesulfonate to whole cells of an EMB-resistant strain indicated structural changes on the cell surface. Structural changes in the cell wall may play an important role in the resistance of M. Gravity resistance, another graviresponse in plants - role of microtubule- membrane-cell wall continuum. Resistance to the gravitational force has been a serious problem for plants to survive on land, after they first went ashore more than million years ago.

Thus, gravity resistance is the principal graviresponse in plants comparable to gravitropism. Nevertheless, only limited information has been obtained for this second gravity response. We have examined the mechanism of gravity resistance using hypergravity conditions produced by centrifugation. The results led a hypothesis on the mechanism of plant resistance to the gravitational force that the plant constructs a tough body by increasing the cell wall rigidity, which are brought about by modification of the cell wall metabolism and cell wall environment, especially pH.

On the other hand, we have shown that gravity signal may be perceived by mechanoreceptors mechanosensitive ion channels on the plasma membrane and amyloplast sedimentation in statocytes is not involved in gravity resistance. Moreover, hypergravity treatment increased the expression levels of genes encoding alpha-tubulin, a component of microtubules and 3-hydroxymethylglutaryl-Coenzyme A reductase HMGR , which catalyzes a reaction producing mevalonic acid, a key precursor of terpenoids such as membrane sterols.

The expression of HMGR and alpha- and beta-tubulin genes increased within several hours after hypergravity treatment, depending on the magnitude of gravity. The determination of levels of gene products as well as the analysis with knockout mutants of these genes by T-DNA insertions in Arabidopsis supports the involvement of both membrane sterols and microtubules in gravity resistance.

These results suggest that structural or physiological continuum of microtubule- cell membrane-cell wall is responsible for plant resistance to the gravitational force. Single wall carbon nanotubes enter cells by endocytosis and not membrane penetration. Background Carbon nanotubes are increasingly being tested for use in cellular applications. Determining the mode of entry is essential to control and regulate specific interactions with cells , to understand toxicological effects of nanotubes, and to develop nanotube-based cellular technologies.

These data suggest energy-dependent endocytosis, as shown previously. We also examined the possibility for non-specific physical penetration of SWCNTs through the plasma membrane. Electrochemical impedance spectroscopy and Langmuir monolayer film balance measurements showed that Pluronic-stabilized SWCNTs associated with membranes but did not possess sufficient insertion energy to penetrate through the membrane.

SWCNTs associated with vesicles made from plasma membranes but did not rupture the vesicles. A novel membrane anchor for FtsZ is linked to cell wall hydrolysis in Caulobacter crescentus. In most bacteria, the tubulin-like GTPase FtsZ forms an annulus at midcell the Z-ring which recruits the division machinery and regulates cell wall remodeling. Although both activities require membrane attachment of FtsZ, few membrane anchors have been characterized.

FtsA is considered to be the primary membrane tether for FtsZ in bacteria, however in Caulobacter crescentus, FtsA arrives at midcell after stable Z-ring assembly and early FtsZ-directed cell wall synthesis. We hypothesized that additional proteins tether FtsZ to the membrane and demonstrate that in C.

FzlC associates with membranes directly in vivo and in vitro and recruits FtsZ to membranes in vitro. As for most known membrane anchors, the C-terminal peptide of FtsZ is required for its recruitment to membranes by FzlC in vitro and midcell recruitment of FzlC in cells.

In vivo, overproduction of FzlC causes cytokinesis defects whereas deletion of fzlC causes synthetic defects with dipM, ftsE and amiC mutants, implicating FzlC in cell wall hydrolysis.

Our characterization of FzlC as a novel membrane anchor for FtsZ expands our understanding of FtsZ regulators and establishes a role for membrane -anchored FtsZ in the regulation of cell wall hydrolysis. Northern gel-blot analysis revealed what appeared to be a single transcript, but three distinct polypeptides were detected in immunogel-blot analyses of the ExGases extracted from growing coleoptiles. Two polypeptides appear in the cell wall , where one polypeptide is constitutive, and the second appears at the time of the maximum rate of elongation and reaches peak activity after elongation has ceased.

The third polypeptide of the ExGase is an extrinsic protein associated with the exterior surface of the plasma membrane. We propose three potential functions for this novel ExGase at the membrane-wall interface.

Multi- walled carbon nanotubes affect drug transport across cell membrane in rat astrocytes. The impact of carbon nanotubes on the cell membrane is an aspect of particular importance and interest in the study of carbon nanotubes' interactions with living systems.

One of the many functions of the cell membrane is to execute substance transport into and out of the cell. We investigated the influence of multi- walled carbon nanotubes MWCNTs on the transport of several compounds across in the cell membrane of rat astrocytes using flow cytometry. Results showed that MWCNTs significantly inhibited cellular uptake of doxorubicin but not the other drugs and the mode of loading made a significant difference in doxorubicin uptake.

Retention of fluorescein, carboxyfluorescein and rhodamine was remarkably higher in MWCNT-exposed cells after an efflux period. A kinetics study also demonstrated slower efflux of intracellular fluorescein and rhodamine The implications of the findings are discussed. The mechanism of the initial steps of bacteriophage infection in Lactococcus lactis subsp. All seven phages adsorbed to the same sites on the host cell wall that are composed, in part, of rhamnose. This was suggested by rhamnose inhibition of phage adsorption to cells , competition between phage c2 and the other phages for adsorption to cells , and rhamnose inhibition of lysis of phage-inoculated cultures.

The adsorption to the cell wall was found to be reversible upon dilution of the cell wall -adsorbed phage. In a reaction step that apparently follows adsorption to the cell wall , all seven phages adsorbed to a host membrane protein named PIP. This was indicated by the inability of all seven phages to infect a strain selected for resistance to phage c2 and known to have a defective PIP protein.

All seven phages were inactivated in vitro by membranes from wild-type cells but not by membranes from the PIP-defective, phage c2-resistant strain. The mechanism of membrane inactivation was an irreversible adsorption of the phage to PIP, as indicated by adsorption of [35S] methionine-labeled phage c2 to purified membranes from phage-sensitive cells but not to membranes from the resistant strain, elimination of adsorption by pretreatment of the membranes with proteinase K, and lack of dissociation of 35S from the membranes upon dilution.

These results suggest that many lactococcal phages adsorb initially to the cell wall and subsequently to host cell membrane protein PIP, which leads to ejection of the phage genome. Treatment of the carrot cells with the cell wall digestion enzymes, driselase, in a sorbitol osmoticum for 1.

Driselase treatment resulted in decreased phosphorylation of a band of Mr 80, which showed almost complete calcium dependence in the osmoticum treated cells ; decreased phosphorylation of a band of Mr 15, which showed little calcium activation, and appearance of a new band of calcium-dependent phosphorylation at Mr 22, These effects appeared not to be due to nonspecific protease activity and neither in vivo nor in vitro exposure to driselase caused a significant loss of Coomassie blue-staining bands on the gels of the isolated plasma membranes.

However, protein phosphorylation was decreased. Adding driselase to the in vitro reaction mixture caused a general decrease in the membrane protein phosphorylation either in the presence or absence of calcium which did not mimic the in vivo response. Cells labeled in vivo with inorganic 32P also showed a response to the Driselase treatment.

An enzymically active driselase preparation was required for the observed responses. Plasma membrane vesicles from wild carrot cells grown in suspension culture were isolated by aqueous two-phase partitioning, and ATP-dependent phosphorylation was measured with [gamma- 32 P]ATP in the presence and absence of calcium.

Driselase treatment resulted in decreased phosphorylation of a band of M r 80, which showed almost complete calcium dependence in the osmoticum treated cells ; decreased phosphorylation of a band of M r 15, which showed little calcium activation, and appearance of a new band of calcium-dependent phosphorylation at M r 22, Cells labeled in vivo with inorganic 32 P also showed a response to the Driselase treatment.

Cell wall polysaccharide synthases are located in detergent-resistant membrane microdomains in oomycetes. The pathways responsible for cell wall polysaccharide biosynthesis are vital in eukaryotic microorganisms.

The corresponding synthases are potential targets of inhibitors such as fungicides. Despite their fundamental and economical importance, most polysaccharide synthases are not well characterized, and their molecular mechanisms are poorly understood. Interestingly, no cellulose synthase activity was detected in the DRMs. The purified DRMs exhibited similar biochemical features as lipid rafts from animal, plant, and yeast cells , although they contained some species-specific lipids.

The results presented here are consistent with a function of lipid rafts in cell polarization and as platforms for sorting specific sets of proteins targeted to the plasma membrane , such as carbohydrate synthases. The involvement of DRMs in the biosynthesis of major cell wall polysaccharides in eukaryotic microorganisms suggests a function of lipid rafts in hyphal morphogenesis and tip growth.

The lantibiotic NAI binds to bactoprenol-bound cell wall precursors and impairs membrane functions. The lantibiotic NAI is active against Gram-positive bacteria including vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus. To identify the molecular basis of its potency, we studied the mode of action in a series of whole cell and in vitro assays and analyzed structural features by nuclear magnetic resonance NMR.

The lantibiotic efficiently interfered with late stages of cell wall biosynthesis and induced accumulation of the soluble peptidoglycan precursor UDP-N-acetylmuramic acid-pentapeptide UDP-MurNAc-pentapeptide in the cytoplasm. Using membrane preparations and a complete cascade of purified, recombinant late stage peptidoglycan biosynthetic enzymes MraY, MurG, FemX, PBP2 and their respective purified substrates, we showed that NAI forms complexes with bactoprenol-pyrophosphate-coupled precursors of the bacterial cell wall.

Titration experiments indicate that first a 1: Furthermore, lipid II and related molecules obviously could not serve as anchor molecules for the formation of defined and stable nisin-like pores, however, slow membrane depolarization was observed after NAI treatment, which could contribute to killing of the bacterial cell. Rapid changes in plasma membrane protein phosphorylation during initiation of cell wall digestion.

An enzymically active driselas preparation was required for the observed responses. Identification of FtsW as a transporter of lipid-linked cell wall precursors across the membrane. Bacterial cell growth necessitates synthesis of peptidoglycan. Assembly of this major constituent of the bacterial cell wall is a multistep process starting in the cytoplasm and ending in the exterior cell surface.

The intracellular part of the pathway results in the production of the membrane -anchored cell wall precursor, Lipid II. After synthesis this lipid intermediate is translocated across the cell membrane. The translocation flipping step of Lipid II was demonstrated to require a specific protein flippase.

Here, we show that the integral membrane protein FtsW, an essential protein of the bacterial division machinery, is a transporter of the lipid-linked peptidoglycan precursors across the cytoplasmic membrane. This study provides the first biochemical evidence for the involvement of an essential protein in the transport of lipid-linked cell wall precursors across biogenic membranes.

Phenyl aldehyde and propanoids exert multiple sites of action towards cell membrane and cell wall targeting ergosterol in Candida albicans. In the present study, two phyto-compounds phenyl aldehyde cinnamaldehyde and propanoid eugenol were selected to explore their modes of action against Candida albicans. Electron microscopy, flow cytometry and spectroscopic assays were employed to determine the targets of these compounds. Treatment of Candida cells by cinnamaldehyde and eugenol at 0.

The binding assays reflected the ability of compounds to bind with the ergosterol. Our findings have suggested that the membrane damaging effects of phenyl aldehyde and propanoids class of compounds is attributed to their ability to inhibit ergosterol biosynthesis and simultaneously binding with ergosterol.

Indirect or secondary action of these compounds on cell wall is also expected as revealed by electron microscopic studies. The Candida albicans plasma membrane plays important roles in cell growth and as a target for antifungal drugs. Analysis of Ca-Sur7 showed that this four transmembrane domain protein localized to stable punctate patches, similar to the plasma membrane subdomains known as eisosomes or MCC that were discovered in S.

The localization of Ca-Sur7 depended on sphingolipid synthesis. In contrast to S. Septins and actin were mislocalized, and cell wall synthesis was very abnormal, including long projections of cell wall into the cytoplasm. These results expand the roles of eisosomes by demonstrating that Sur7 is needed for proper plasma membrane organization and cell wall synthesis. A conserved Cys motif in the first extracellular loop of fungal Sur7 proteins is similar to a characteristic motif of the claudin proteins that form tight junctions in animal cells , suggesting a common role for these tetraspanning membrane proteins in forming specialized plasma membrane domains.

Plasma membrane-cell wall connections: Tradescantia virginiana leaf epidermal cells were plasmolysed by sequential treatment with 0. Plasmolysis revealed adhesion of the plasma membrane to the cell wall at sites coinciding with cytoskeletal arrays involved in the polarisation of cells undergoing asymmetric divisions--cortical actin patch--and in the establishment and maintenance of the division site--preprophase band of microtubules and filamentous F actin. The majority of cells retained adhesions at the actin patch throughout mitosis.

After the breakdown of the nuclear envelope, plasmolysis had a dramatic effect on spindle orientation, cell plate formation, and the plane of cytokinesis.

Spindles were rotated at abnormal angles including tilted into the plane of the epidermis. Cell plates formed but were quickly replaced by vacuole-like intercellular compartments containing no Tinopal-stainable cell wall material. This compartment usually opened to the apoplast at one side, and cytokinesis was completed by the furrow extending across the protoplast. This atypical cytokinesis was facilitated by a phragmoplast containing microtubules and F-actin.

Progression of the furrow was unaffected by 25 micrograms of cytochalasin B per ml but inhibited by 10 microM oryzalin. Phragmoplasts were contorted and misguided and cytokinesis prolonged, indicating severe disruption to the guidance mechanisms controlling phragmoplast expansion.

The mechanism of human T-lymphocyte activation by the pathogenic yeast Cryptococcus neoformans has not been established. Previous investigations have suggested that C. Because of the potential importance of the mechanism of T- cell activation for our understanding of the immune response to C.

The T- cell response to C. However, allogeneic cells were sufficient for accessory cell function, indicating that the response was not major histocompatibility complex restricted. The percentage of T cells in the cell cycle was higher than that with the recall antigen tetanus toxoid but lower than that with the mitogenic lectin phytohemagglutinin A or the superantigen Staphylococcus enterotoxin B.

Compared to the case for most mitogens or superantigens, the proliferative response is late and the number of T cells that enter the cell cycle and the precursor frequency are low, indicating that the mitogenic effect is modest.

However, the mitogenic effect of C. Crystal structure of MraY, an essential membrane enzyme for bacterial cell wall synthesis. MraY phospho-MurNAc-pentapeptide translocase is an integral membrane enzyme that catalyzes an essential step of bacterial cell wall biosynthesis: MraY has long been considered a promising target for the development of antibiotics, but the lack of a structure has hindered mechanistic understanding of this critical enzyme and the enzyme superfamily in general.

Single- wall carbon nanotube-based proton exchange membrane assembly for hydrogen fuel cells. A membrane electrode assembly MEA for hydrogen fuel cells has been fabricated using single- walled carbon nanotubes SWCNTs support and platinum catalyst. Scanning electron microscopy and Raman spectroscopy showed that the nanotubes and the platinum retained their nanostructure morphology on the carbon fiber surface. Electrochemical impedance spectroscopy EIS revealed that the carbon nanotube-based electrodes exhibited an order of magnitude lower charge-transfer reaction resistance R ct for the hydrogen evolution reaction HER than did the commercial carbon black CB -based electrodes.

Relative contribution of the cell wall , cytoplasmic membrane , and cytoplasm to the gram-positive characteristic of Bacillus megaterium. Protoplasts of Bacillus megaterium were confirmed as being gram-negative, as reported by Gerhardt et al. Bacterial strains living in the environment must cope with the toxic compounds originating from humans production. Surface bacterial structures, cell wall and cytoplasmic membrane , surround each bacterial cell and create selective barriers between the cell interior and the outside world.

They are a first site of contact between the cell and toxic compounds. Organic pollutants are able to penetrate into cytoplasmic membrane and affect membrane physiological functions.

Bacteria had to evolve adaptation mechanisms to counteract the damage originated from toxic contaminants and to prevent their accumulation in cell. This review deals with various adaptation mechanisms of bacterial cell concerning primarily the changes in cytoplasmic membrane and cell wall. Low energy consumption of cell adaptation is required to provide other physiological functions. Bacteria able to survive in toxic environment could help us to clean contaminated areas when they are used in bioremediation technologies.

Proteomics of plasma membranes from poplar trees reveals tissue distribution of transporters, receptors, and proteins in cell wall formation. ATP-binding cassette transporters all members of subfamilies B, C, and G and receptor-like kinases four subfamilies were two of the largest protein families found, and the members of these two families showed pronounced tissue distribution.

Leaf plasma membranes were characterized by a very high proportion of transporters, constituting almost half of the integral proteins. Proteins involved in cell wall synthesis such as cellulose and sucrose synthases and membrane trafficking were most abundant in xylem plasma membranes in agreement with the role of the xylem in wood formation. Twenty-five integral proteins and 83 soluble proteins were exclusively found in xylem plasma membranes , which identifies new candidates associated with cell wall synthesis and wood formation.

Among the proteins uniquely found in xylem plasma membranes were most of the enzymes involved in lignin biosynthesis, which suggests that they may exist as a complex linked to the plasma membrane. A laser microsurgical method of cell wall removal allows detection of large-conductance ion channels in the guard cell plasma membrane. Application of patch clamp techniques to higher-plant cells has been subject to the limitation that the requisite contact of the patch electrode with the cell membrane necessitates prior enzymatic removal of the plant cell wall.

Because the wall is an integral component of plant cells , and because cell-wall -degrading enzymes can disrupt membrane properties, such enzymatic treatments may alter ion channel behavior.

We compared ion channel activity in enzymatically isolated protoplasts of Vicia faba guard cells with that found in membranes exposed by a laser microsurgical technique in which only a tiny portion of the cell wall is removed while the rest of the cell remains intact within its tissue environment.

These data indicate that ion channels are present in plant membranes that are not detected by conventional patch clamp techniques involving the production of individual plant protoplasts isolated from their tissue environment by enzymatic digestion of the cell wall. Given the large conductances of the channels revealed by laser-assisted patch clamping, we hypothesize that these channels play a significant role in the regulation of ion content and electrical signalling in guard cells.

Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown.

Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis Arabidopsis thaliana , are disrupted by the RGD arginine-glycine-aspartic acid tripeptide sequence, a characteristic cell adhesion motif in mammals. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis.

Moreover, the two peptides also disrupted cell wall -plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides.

Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain. The lectin domain of one of these, At5g, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces.

Lectin receptor kinases participate in protein-protein interactions to mediate plasma membrane-cell wall adhesions in Arabidopsis. High affinity RGD-binding sites at the plasma membrane of Arabidopsis thaliana links the cell wall. The heptapeptide Tyr-Gly-Arg-Gly-Asp-Ser-Pro containing the sequence Arg-Gly-Asp RGD--the essential structure recognised by animal cells in substrate adhesion molecules was tested on epidermal cells of onion and cultured cells of Arabidopsis upon plasmolysis. Dramatic changes were observed on both types of cells following treatment: Protoplasts isolated from Arabidopsis cells agglutinate in the presence of ProNectinF, a genetically engineered protein of 72 kDa containing 13 RGD sequences: The addition of the RGD-heptapeptide disrupted the adhesion between the protoplasts.

Purified plasma membrane from Arabidopsis cells exhibits specific binding sites for the iodinated RGD-heptapeptide. The binding is saturable, reversible, and two types of high affinity sites Kd1 approximately 1 nM, and Kd2 approximately 40 nM can be discerned. Competitive inhibition by several structurally related peptides and proteins noted the specific requirement for the RGD sequence. Thus, the RGD-binding activity of Arabidopsis fulfils the adhesion features of integrins, i.

Cell wall accumulation of fluorescent proteins derived from a trans-Golgi cisternal membrane marker and paramural bodies in interdigitated Arabidopsis leaf epidermal cells. In most dicotyledonous plants, leaf epidermal pavement cells develop jigsaw puzzle-like shapes during cell expansion. Therefore, visualization of membrane trafficking in leaf pavement cells should contribute an understanding of the mechanism of plant cell morphogenesis.

To reveal membrane trafficking in pavement cells , we observed monomeric red fluorescent protein-tagged rat sialyl transferases, which are markers of trans-Golgi cisternal membranes , in the leaf epidermis of Arabidopsis thaliana. Quantitative fluorescence imaging techniques and immunoelectron microscopic observations revealed that accumulation of the red fluorescent protein occurred mostly in the curved regions of pavement cell borders and guard cell ends during leaf expansion.

Transmission electron microscopy observations revealed that apoplastic vesicular membrane structures called paramural bodies were more frequent beneath the curved cell wall regions of interdigitated pavement cells and guard cell ends in young leaf epidermis.

In addition, pharmacological studies showed that perturbations in membrane trafficking resulted in simple cell shapes. These results suggested possible heterogeneity of the curved regions of plasma membranes , implying a relationship with pavement cell morphogenesis. An enzyme complex responsible for the TUA chain biosynthesis was purified and characterized. TUAS displays hydrophobic properties and is found primarily associated with the cytoplasmic membrane.

The purified TUAS contains carotinoids and lipids. TUAS activity is diminished by phospholipase digestion. We propose that TUAS serves as a multitasking polysaccharide assembling station on the bacterial membrane. Actin filaments regulate the adhesion between the plasma membrane and the cell wall of tobacco guard cells. During the opening and closing of stomata, guard cells undergo rapid and reversible changes in their volume and shape, which affects the adhesion of the plasma membrane PM to the cell wall CW.

The dynamics of actin filaments in guard cells are involved in stomatal movement by regulating structural changes and intracellular signaling. However, it is unclear whether actin dynamics regulate the adhesion of the PM to the CW. In this study, we investigated the relationship between actin dynamics and PM-CW adhesion by the hyperosmotic-induced plasmolysis of tobacco guard cells. We found that actin filaments in guard cells were depolymerized during mannitol-induced plasmolysis.

However, treatment with latrunculin B alleviated the RGDS peptide-induced plasmolysis and endocytosis. Our results reveal that the actin depolymerization is involved in the regulation of the PW-CW adhesion during hyperosmotic-induced plasmolysis in tobacco guard cells. In this study, a series of nanocomposite membranes were fabricated with the PVA-influenced functionalized MWCNTs reinforced into the Nafion polymer matrix by a solution casting method. After that, the nanocomposite membranes were characterized by thermo-gravimetric analysis TGA to observe the thermal enhancement caused by effective cross-linking between the f-MWCNTs with the composite polymer matrixes.

Diffusion of nitric oxide across cell membranes of the vascular wall requires specific connexin-based channels. NO is generated within cells and frequently must be transferred to responsive neighboring cells , as occurs in the endothelium-dependent relaxation of smooth muscle cells observed in blood vessels. It is thought that NO diffuses freely across cell membranes , but it may also permeate through low resistant membrane pathways.

Here, we describe the participation of connexin Cx -formed channels in the NO transport across cell membranes and between endothelial and smooth muscle cells. We used a water-soluble NO donor of high molecular weight S-nitrosylated albumin, BSA-NO that does not permeate through cell membranes or Cx-based channels and the NO-sensitive dye 4,5-diaminofluorescein diacetate to detect changes of intracellular NO concentration.

We found that NO generated in the extracellular space was not detected intracellularly in Cx-deficient HeLa cells , suggesting that cell membrane represents a significant diffusion barrier for NO transfer. In contrast, NO closed hemichannels of HeLa-Cx32 cells , which otherwise are permeable to NO if are opened by a divalent cation-free extracellular solution. Consistent with this, blockade of Cx-based channels abolished the myoendothelial NO transfer and associated NO-dependent vasodilation induced by acethylcholine.

These results indicate that Cx-based channels play a key role in the NO-dependent tonic control of vascular function and may direct the NO signal to specific targets, which provides a novel mechanistic basis for the critical role of Cxs in cell-cell communication in the vessel wall. Perturbation of the Staphylococcus aureus cytoplasmic membrane CM is felt to play a key role in the microbicidal mechanism of many antimicrobial peptides APs. We hypothesized that the relationships between MP and killing may differ for distinct APs.

Four APs with different structure-activity relationships were examined: MP was quantified fluorometrically by calcein release. All APs tested, except polymyxin B, caused concentration-dependent MP and killing of whole cells , but not of protoplasts. The reduced AP susceptibility of protoplasts was associated with increased cardiolipin and lysyl-phosphatidylglycerol content and reduced fluidity of their CMs.

Collectively, these results indicate that i structurally distinct APs likely exert their staphylocidal effects by differing mechanisms, ii MP is not the sole event leading to AP-induced staphylocidal activity, iii a complex interrelationship exists between the CM and CW in AP-induced killing, and iv liposomes modeled upon whole cell or protoplast CMs can recapitulate the respective susceptibilities to killing by distinct APs. Peptidoglycan is the major component of the cell envelope of virtually all bacteria.

It has structural roles and acts as a selective sieve for molecules from the outer environment. Peptidoglycan synthesis is therefore one of the most important biogenesis pathways in bacteria and has been studied extensively over the last twenty years.

The pathway starts in the cytoplasm, continues in the cytoplasmic membrane and finishes in the periplasmic space, where the precursor is polymerized into the peptidoglycan layer.

A number of proteins involved in this pathway, such as the Mur enzymes and the penicillin binding proteins PBPs , have been studied and regarded as good targets for antibiotics.

The present review focuses on the membrane steps of peptidoglycan synthesis that involve two enzymes, MraY and MurG, the inhibitors of these enzymes and the inhibition mechanisms. We also discuss the challenges of targeting these two cytoplasmic membrane associated proteins in bacterial cells and the perspectives on how to overcome the issues. Knockout of the alanine racemase gene in Aeromonas hydrophila HBNUAh01 results in cell wall damage and enhanced membrane permeability.

This study focused on the alanine racemase gene alr-2 , which is involved in the synthesis of d-alanine that forms the backbone of the cell wall. When the mutant was supplemented with d-alanine, growth was unaffected; deprivation of d-alanine caused the growth arrest of the starved mutant cells , but not cell lysis. No alanine racemase activity was detected in the culture of the mutant.

Additionally, a membrane permeability assay showed increasing damage to the cell wall during d-alanine starvation. No such damage was observed in the wild type during culture.

Scanning and transmission electron microscopy analyses revealed deficiencies of the cell envelope and perforation of the cell wall. Leakage of UV-absorbing substances from the mutants was also observed. Thus, the partial viability of the mutants and their independence of d-alanine for growth indicated that inactivation of alr-2 does not impose an auxotrophic requirement for d-alanine. Effect of chirality and length on the penetrability of single- walled carbon nanotubes into lipid bilayer cell membranes.

The ability of carbon nanotubes to enter the cell membrane acting as drug-delivery vehicles has yielded a plethora of experimental investigations, mostly with inconclusive results because of the wide spectra of carbon nanotube structures.

Because of the virtual impossibility of synthesizing CNTs with distinct chirality, we report a parametric study on the use of molecular dynamics to provide better insight into the effect of the carbon nanotube chirality and the aspect ratio on the interaction with a lipid bilayer membrane.

The simulation results indicated that a single- walled carbon nanotube utilizes different time-evolving mechanisms to facilitate their internalization within the membrane. These mechanisms comprise both penetration and endocytosis. It was observed that carbon nanotubes with higher aspect ratios penetrate the membrane faster whereas shorter nanotubes undergo significant rotation during the final stages of endocytosis. Furthermore, nanotubes with lower chiral indices developed significant adhesion with the membrane.

This adhesion is hypothesized to consume some of the carbon nanotube energy, thus resulting in longer times for the nanotube to translocate through the membrane. Combined effect of synthetic enterocin CRL35 with cell wall , membrane -acting antibiotics and muranolytic enzymes against Listeria cells. To evaluate the inhibition effectiveness of enterocin CRL35 in combination with cell wall , membrane -acting antibiotics and muranolytic enzymes against the foodborne pathogen Listeria.

Synthetic enterocin CRL35 alone and in combination with monensin, bacitracin, gramicidin, mutanolysin and lysozyme were used in this study.

Antibiotics showed positive interactions with the bacteriocin in both strains tested. On the other hand, when mutanolysin and enterocin CRL35 were added to resting cells in a buffer system, the lytic effect of mutanolysin was enhanced.

However, the addition of mutanolysin showed no effect on the growth of L. Moreover, mutanolysin allowed the overgrowth of L. Based on our results, we conclude that the combination of synthetic enterocin CRL35 with some antibiotics is effective against L.

The effectiveness of the combination of synthetic enterocin CRL35 with muramidases seems to depend on complex environments, and more detailed studies need to be performed to elucidate this issue.

Enterocin CRL35 represents a promising agent that not only can ensure the quality and safety of food but it can also be combined with several antimicrobial agents important in the medical field. Deciphering the Metabolism of Undecaprenyl-Phosphate: During the biogenesis of bacterial cell-wall polysaccharides, such as peptidoglycan, cytoplasmic synthesized precursors should be trafficked across the plasma membrane.

This essential process requires a dedicated lipid, undecaprenyl-phosphate that is used as a glycan lipid carrier. The sugar is linked to the lipid carrier at the inner face of the membrane and is translocated toward the periplasm, where the glycan moiety is transferred to the growing polymer.

Undecaprenyl-phosphate originates from the dephosphorylation of its precursor undecaprenyl-diphosphate, with itself generated by de novo synthesis or by recycling after the final glycan transfer. Undecaprenyl-diphosphate is de novo synthesized by the cytosolic cis-prenyltransferase undecaprenyl-diphosphate synthase, which has been structurally and mechanistically characterized in great detail highlighting the condensation process. In contrast, the next step toward the formation of the lipid carrier, the dephosphorylation step, which has been overlooked for many years, has only started revealing surprising features.

In contrast to the previous step, two unrelated families of integral membrane proteins exhibit undecaprenyl-diphosphate phosphatase activity: BacA and members of the phosphatidic acid phosphatase type 2 super-family, raising the question of the significance of this multiplicity.

Moreover, these enzymes establish an unexpected link between the synthesis of bacterial cell-wall polymers and other biological processes.

In the present review, the current knowledge in the field of the bacterial lipid carrier, its mechanism of action, biogenesis, recycling, regulation, and future perspective works are presented. Plants are able to generate large leaf surfaces that act as two-dimensional solar panels with a minimum investment in building material, thanks to a hydrostatic skeleton. This requires high intracellular pressures up to 1 MPa , which depend on the presence of strong cell walls. The walls of growing cells also called primary walls , are remarkably able to reconcile extreme tensile strength up to MPa with the extensibility necessary for growth.

All walled organisms are confronted with this dilemma - the need to balance strength and extensibility - and bacteria, fungi and plants have evolved independent solutions to cope. In this Primer, we discuss how plant cells have solved this problem, allowing them to support often very large increases in volume and to develop a broad variety of shapes Figure 1A,B,D.

This shape variation reflects the targeted deposition of wall material combined with local variations in cell-wall extensibility, processes that remain incompletely understood. Once the cell has reached its final size, it can lay down secondary wall layers, the composition and architecture of which are optimized to exert specific functions in different cell types Figure 1E-G.

Specialized secondary walls , such as those constituting seed mucilage, are stored in a dehydrated form in seedcoat epidermis cells and show rapid swelling upon hydration of the seed.

Other walls , in particular in reserve tissues, can accommodate large amounts of storage polysaccharides, which can be easily mobilized as a carbon source. Physiological and transcriptional responses of Saccharomyces cerevisiae to d-limonene show changes to the cell wall but not to the plasma membrane.

Monoterpenes can, upon hydrogenation, be used as light-fraction components of sustainable aviation fuels. Fermentative production of monoterpenes in engineered microorganisms, such as Saccharomyces cerevisiae, has gained attention as a potential route to deliver these next-generation fuels from renewable biomass.

However, end product toxicity presents a formidable problem for microbial synthesis. Due to their hydrophobicity, monoterpene inhibition has long been attributed to membrane interference, but the molecular mechanism remains largely unsolved.

We found no alterations in membrane fluidity, structural membrane integrity, or fatty acid composition after the solvent challenge. A 4-fold increase in the mean fluorescence intensity per cell using calcofluor white stain and increased sensitivity to cell wall -degrading enzymes demonstrated that limonene disrupts cell wall properties. Global transcript measurements confirmed the membrane integrity observations by showing no upregulation of ergosterol or fatty acid biosynthesis pathways, which are commonly overexpressed in yeast to reinforce membrane rigidity during ethanol exposure.

This is the first report demonstrating that cell wall , rather than plasma membrane , deterioration is the main source of monoterpene inhibition. We show that limonene can alter the structure and function of the cell wall , which has a clear effect on cytokinesis.

Proteins in the cell wall and membrane of Cryptococcus neoformans stimulate lymphocytes from both adults and fetal cord blood to proliferate. Cryptococcus neoformans is an encapsulated yeast that infects patients who have defective cell -mediated immunity, including AIDS, but rarely infects individuals who have intact cell -mediated immunity.

Studies of the immune response to C. The goal of this study was to separate C. The lymphocyte response to fungal culture medium, whole organisms, disrupted organisms, and the yeast intracellular fraction or cell wall and membrane was studied by determining thymidine incorporation and by determining the number of lymphocytes at various times after stimulation. The cell wall and membrane of C. The optimal response occurred on day 7 of incubation, with 4 x 10 5 peripheral blood mononuclear cells per well and with 13 microg of cryptococcal protein per ml.

The number of lymphocytes increased with time in culture, indicating that thymidine incorporation was accompanied by proliferation. Proteinase K treatment of the cell wall and membrane abrogated lymphocyte proliferation, indicating that the molecule was a protein. At least 18 discrete bands were resolved from the cell wall and membrane. Since a large percentage of healthy adults responded to the cryptococcal cell wall and membrane , a mitogenic effect was investigated by testing proliferation of fetal cord blood.

An investigation into plasmolysis in the oomycete Achlya bisexualis reveals that membrane-wall attachment points are sensitive to peptides containing the sequence RGD and that cell wall deposition can occur despite retraction of the protoplast.

The structure and function of membrane-wall attachment sites in walled cells , and how these relate to animal focal adhesions, is an area that is poorly understood. During seedling growth, performance-related traits were measured.

A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits.

Prevalence of sensitization to weed pollens of Humulus scandens,Artemisia vulgaris, and Ambrosia artemisiifolia in northern China. Weed pollens are common sources of allergens worldwide. The prevalence of weed pollen sensitization is not yet fully known in China. The purpose of this study was to investigate the prevalence of sensitization to weed allergens from Artemisia, Ambrosia ,and Humulus in northern China.

A total of subjects aged from 5 to 68 years visiting our clinic from June to October underwent intradermal testing using a panel of 25 allergen sources.

Subjects with positive skin responses to any pollen were further tested for their serum concentrations of IgE antibodies against Artemisia vulgaris, Ambrosia artemisiifolia ,and Humulus scandens,and against the purified allergens,Art v 1 and Amb a 1. Of 1 subjects, had positive intradermal reactions to pollen and donated serum for IgE testing. The prevalence of positive intradermal responses to pollens of Artemisia sieversiana,Artemisia annua,A.

Among the intradermal positive subjects,the prevalence of specific IgE antigens to A. The prevalence of specific IgE antigens to the allergen Art v 1 was The correlation between the presence of IgE antibodies specific to A. There were no correlations between the presence of IgE antibodies to H.

The intradermal prevalence of weed pollen sensitization among allergic subjects in northern China is about Correlations of specific IgE antibodies suggest that pollen allergens from Artemisia and Humulus are independent sources for primary sensitization. Mesoscale atmospheric transport of ragweed pollen allergens from infected to uninfected areas.

Allergenic ragweed Ambrosia spp. However, the action of air temperature, humidity and solar radiation on pollen grains in the atmosphere could impact on the ability of long distance transported LDT pollen to maintain allergenic potency.

Here, we report that the major allergen of Ambrosia artemisiifolia pollen Amb a 1 collected in ambient air during episodes of LDT still have immunoreactive properties. The amount of Amb a 1 found in LDT ragweed pollen grains was not constant and varied between episodes. In addition to allergens in pollen sized particles, we detected reactive Amb a 1 in subpollen sized respirable particles. These findings suggest that ragweed pollen grains have the potential to cause allergic reactions, not only in the heavily infested areas but, due to LDT episodes, also in the regions unaffected by ragweed populations.

Glyphosate resistance in common ragweed Ambrosia artemisiifolia L. Glyphosate is one of the most commonly used broad-spectrum herbicides over the last 40 years. Due to widespread adoption of glyphosate-resistant GR crop technology, especially, corn, cotton, and soybean, several weed species in agronomic situations have developed resistance to this herbicide. Glyphosate resistance in giant ragweed Ambrosia trifida L.

A giant ragweed population from a glyphosate-resistant GR soybean field in Mississippi was suspected to be resistant to glyphosate. Greenhouse and laboratory studies were conducted to confirm and quantify the magnitude of glyphosate resistance in the giant ragweed population and to elucidate the p Full Text Available Only a limited spectrum of active substances is available for weed control in leguminous plants and sunflowers. Since the official plant protection service in Brandenburg conducts herbicide field trials in these crop species in the region around Drebkau for the investigation of practicable approaches for control of Ambrosia artemisiifolia.

For the cultivation of lupins only pre-emergence herbicides are registered. Due to the high density of A. Likewise, the performance of authorised herbicides in sunflowers is insufficient. In the region concerned cultivation of grain legumes and sunflowers is limited in areas with high coverage rate of A.

Full Text Available Since the beginning of common ragweed registration in North Rhine-Westphalia in there have been ragweed records, among them 31 populations with more than individuals. Common ragweed is not yet established in North Rhine-Westphalia but seems to do very well on sandy soils in the Lowland. North Rhine-Westphalia is tackling common ragweed in an early stage of invasion and will continue the strategy of rapid response to achieve a total eradication.

Thirty-three countries have already signed the Memorandum of Understanding and over researchers with specialists in weed research, invasive alien species management, ecology, aerobiology, allergology and economics are registered participants of SMARTER.

COST Actions interlink nationally funded research projects and enable and finance conferences, working groups, training schools and research exchanges. SMARTER aims to initiate and develop long-term and sustainable control methods, to integrate these into existing mechanical and chemical control measures, and to quantify the success of these measures both for agriculture and health.

The focus is on biological control methods with insects and fungi especially using alien species from the area of origin of Ambrosia and vegetation management to achieve a competitive plant cover. For this, we develop and parameterize models, starting from the population dynamics of Ambrosia , on the impact of control measures on the frequency and distribution of Ambrosia and finally on pollen counts and allergy occurrences, each with both ecological and economic components.

The necessary data are derived from the many experiments that we carry out in well-coordinated studies across Europe. SMARTER will allow the various stakeholders to select optimal habitat- and region-specific combinations of control methods.

After an introduction and overview of the structure and the state of the Action, we briefly describe two planned activities typical for our Action, a study on the population dynamics of Ambrosia in different climates and habitats in Europe as a basis for estimating the efficiency of control measures, and an interdisciplinary study to clarify the impact the of North American native Ambrosia leaf beetle Ophraella communa Coleoptera.

Climate-change-induced range shifts of three allergenic ragweeds Ambrosia L. Full Text Available Invasive allergenic plant species may have severe health-related impacts.

In this study we aim to predict the effects of climate change on the distribution of three allergenic ragweed species Ambrosia spp. We estimate that by year , the distribution range of all three ragweed species increases towards Northern and Eastern Europe under all climate scenarios. We conclude that areas in Europe affected by severe ragweed associated allergy problems are likely to increase substantially by year , affecting millions of people.

To avoid this, management strategies must be developed that restrict ragweed dispersal and establishment of new populations. Precautionary efforts should limit the spread of ragweed seeds and reduce existing populations. Only by applying cross-countries management plans can managers mitigate future health risks and economical consequences of a ragweed expansion in Europe.

Invasive allergenic plant species may have severe health-related impacts. We quantify the extent of the increase in 'high allergy risk' HAR areas, i. Effects of climate change and seed dispersal on airborne ragweed pollen loads in Europe. Common ragweed Ambrosia artemisiifolia is an invasive alien species in Europe producing pollen that causes severe allergic disease in susceptible individuals. Ragweed plants could further invade European land with climate and land-use changes. However, airborne pollen evolution depends not only on plant invasion, but also on pollen production, release and atmospheric dispersion changes.

To predict the effect of climate and land-use changes on airborne pollen concentrations, we used two comprehensive modelling frameworks accounting for all these factors under high-end and moderate climate and land-use change scenarios. We estimate that by airborne ragweed pollen concentrations will be about 4 times higher than they are now, with a range of uncertainty from 2 to 12 largely depending on the seed dispersal rate assumptions.

About a third of the airborne pollen increase is due to on-going seed dispersal, irrespective of climate change. The remaining two-thirds are related to climate and land-use changes that will extend ragweed habitat suitability in northern and eastern Europe and increase pollen production in established ragweed areas owing to increasing CO2. Therefore, climate change and ragweed seed dispersal in current and future suitable areas will increase airborne pollen concentrations, which may consequently heighten the incidence and prevalence of ragweed allergy.

Full Text Available Since the common ragweed , Ambrosia artemisiifolia , which was introduced from North America has also been found in Bavaria in larger stocks and has an increasing tendency to spread. After receiving the report of the Bavarian Ministry of Health, the Bavarian Parliament addressed the implications for health. There was consensus across all political groups to combat the plant. The 96 district administration authorities, which each have a trained ragweed officer, report to the registration office on new verified ragweed locations with more than plants.

The reports of common ragweed stands are filed by citizens or through research by the district administration authorities, who are also responsible for supporting the fight against stocks. On behalf of the Bavarian Ministry of Health, the Working Group Biodiversity monitors the situation and finds many new locations.

Since , new common ragweed stocks were registered. After control measures there are currently known remaining stocks. Since , however, the populated area has tripled. This means that the control measures need further improvement. This is especially true for the common ragweed stocks along roadsides where the plants have increased massively in recent years.

Sustainable control has proved to be particularly difficult. Ragweed -induced allergic rhinoconjunctivitis: Ragweed -induced allergic rhinoconjunctivitis has long been seen as a major immunologic condition in Northern America with high exposure and sensitization rates in the general population. The invasive occurrence of ragweed A. Possible explanations for its worldwide spread are climate change and urbanization, as well as pollen transport over long distances by globalized traffic and winds.

Due to the increasing disease burden worldwide, and to the lack of a current and comprehensive overview, this study aims to review the current and emerging treatment options for ragweed -induced rhinoconjunctivitis.

Sound clinical evidence is present for the symptomatic treatment of ragweed -induced allergic rhinoconjunctivitis with oral third-generation H1-antihistamines and leukotriene antagonists. The topical application of glucocorticoids has also been efficient in randomized controlled clinical trials. Combined approaches employing multiple agents are common. The mainstay of causal treatment to date, especially in Northern America, is subcutaneous immunotherapy with the focus on the major allergen, Amb a 1.

Beyond this, growing evidence from several geographical regions documents the benefit of sublingual immunotherapy. Future treatment options promise more specific symptomatic treatment and fewer side effects during causal therapy. Novel antihistamines for symptomatic treatment are aimed at the histamine H3-receptor. New adjuvants with toll-like receptor 4 activity or the application of the monoclonal anti-immunoglobulin E antibody, omalizumab, are supposed to enhance conventional immunotherapy.

An approach targeting toll-like receptor 9 by. Full Text Available The European Union handed over the regulation of common ragweed Ambrosia artemisiifolia to the member states. Austrian administration started to ask for control measures, i.

Any sustainable control measure must focus on the reduction of seeds produced by the annual ragweed. Seed bank dimension of ragweed turned out to be a good evaluation tool for any control measure. To evaluate the importance of different spreading mechanisms of dispersal, a need for serious figures can be stated.

Based on our seed trap experiments and comparable slip stream experiments by German botanists, the efficiency of vehicles in spreading ragweed over long distances was low. However, machines used by road services cutter, moulder turned out to spread thousands of seeds. Besides, there is serious indication that trucking agricultural food and seeds over long distances is relevant for ragweed seed dispersal. Dispersal of thousands of ragweed seeds from contaminated agricultural fields to fields not yet infested is caused by harvesters and other agricultural machines.

Regulations to reduce the ragweed load in traded agricultural goods are to be implemented in future. Small populations of ragweed should be simply uprooted and composted as long as they bear no flowers.

Various possibilities are known for control of common ragweed in agricultural fields with mechanical and chemical methods. Limits are set in sunflowers because sunflower and ragweed are botanically related. The legal obligation of reporting and control — introduced in Switzerland a couple of years ago — allowed the development of specific distribution maps and enhanced the quality of control measures.

Facts and figures from the Canton of Geneva prove that the ragweed invasion has been stopped, but the species is not eradicated. The results of Geneva represent the results of good ragweed control in the whole country. Beside agriculture, traffic infrastructure, building sites, gravel pits and urban park and garden areas are sensible to ragweed invasion.

The responsibility of individuals helps to improve control efficiency even if financial funds are small. A sustainable control success depends on the efficiency to hamper seed production. The reduction of pollen quantity in the air in a long term is part of the earnings for the control effort.

Actually, the publicity of common ragweed is fed by specialist information and its distribution in the media. It would be an interesting task to develop in our fast moving era an awareness level comparable to that of the stinging nettle. Effect of heavy metals on seed germination and seedling growth of common ragweed and roadside ground cover legumes.

It creates empty niches vulnerable to weed establishment such as common ragweed Ambrosia artemisiifolia. We hypothesized that heavy metal stresses may drive such species shifts along roadside edges. A growth chamber experiment was conducted to assess effects of metals Zn, Pb, Ni, Cu, and Cd on germination and seedling behaviors of roadside weed A.

All metals inhibited T. Low levels of Pb and Ni promoted germination initiation of A. Metal additions hindered seedling growth of all test species, and the inhibitory effect on the belowground growth was greater than on the aboveground growth. Seedling mortality was lowest in A. In conclusion, the successful establishment of A. The findings also revealed that L.

Full Text Available Identifying the sensitive habitats with high invasibility is critical for management of biological invasion. Ragweed Ambrosia artemisiifolia Linn. The experiment took ragweek as a model invader to reveal the community invisibility of different habitats. The results suggested that the presence of native species had strong negative effects on the performance of the invader species. The presence of native species occupied the niche space and left few empty niches for the colonization of the invaders.

The results revealed that planting native species in bare soils, and maintaining the native communities with high diversity, was effective strategies to control the invasion of exotic species.

The present situation of the plant was analyzed in Qinhuangdao region, and the new campus was taken as an example to inves-tigate the effects of human activity disturbance on A. The invasiveness of A. In present, the plant was a community construction species in this region, and showed no invasion. The investigated results showed that A. However, in the habitat disturbed by human activities, the plant had relatively high advantage.

Therefore, excessive human activity disturbance should be prevented to control the invasive plant, by which to protect the local ecological environment. Ragweed subpollen particles of respirable size activate human dendritic cells. Full Text Available Ragweed Ambrosia artemisiifolia pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles SPPs of respirable size upon hydration.

In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells moDCs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells DCs in the airways and SPPs' NAD PH oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins. Characterizing restriction enzyme-associated loci in historic ragweed Ambrosia artemisiifolia voucher specimens using custom-designed RNA probes.

Population genetic studies of non-model organisms frequently employ reduced representation library RRL methodologies, many of which rely on protocols in which genomic DNA is digested by one or more restriction enzymes. However, because high molecular weight DNA is recommended for these protocol Ambrosia is a kind of invasive alien weed, whose invasion not only threatens native biodiversity and ecosystems, but also causes considerable economic loss.

In order to control the damage of Ambrosia effectively, on the basis of introducing mechanical, chemical and biological control methods, the insufficiencies of them were clarified and an integrated control measure was proposed. Exotic plant invasion presents a serious threat to native ecosystem structure and function. Little is known about the role of soil microbial communities in facilitating or resisting the spread of invasive plants into native communities.

The purpose of this research is to understand how the invasive annual plantAmbrosiaartemisiifoliaL. The soil characteristics of different areas invaded by A. Greenhouse experiments were designed to assess the effect ofA. The results showed that the soil organic C content was the highest in heavily invaded sites, the lowest in native plant sites, and intermediate in newly invaded sites.

Soil available N, P and K concentrations in heavily invaded site were 2. Soil pH decreased asA. The soil microbial community structure was clearly separated in the three types of sites, andA.

Soil biota of invaded sites inhibits growth of co-occurring plants Galinsoga parvilfora Cav. Results of the present study indicated thatA. Northern ragweed ecotypes flower earlier and longer in response to elevated CO2: Significant changes in plant phenology and flower production are predicted over the next century, but we know relatively little about geographic patterns of this response in many species, even those that potentially impact human wellbeing.

We tested for variation in flowering responses of the allergenic plant, Ambrosia artemisiifolia common ragweed. We hypothesized that northern ecotypes adapted to shorter growing seasons would flower earlier than their southern counterparts, and thus disproportionately allocate carbon gains from CO2 to reproduction. As predicted, latitude of origin and carbon dioxide level significantly influenced the timing and magnitude of flowering.

Reproductive onset occurred earlier with increasing latitude, with concurrent increases in the number of flowers produced. Elevated carbon dioxide resulted in earlier reproductive onset in all ecotypes, which was significantly more pronounced in the northern populations. We interpret our findings as evidence for ecotypic variation in ragweed flowering time, as well in responses to CO2.

Thus, the ecological and human health implications of common ragweed 's response to global change are likely to depend on latitude. We conclude that increased flower production, duration, and possibly pollen output, can be expected in Northeastern United States with rising levels of CO2. The effects are likely, however, to be most significant in northern parts of the region. The invasive alien species Ambrosia artemisiifolia common or short ragweed is increasing its range in Europe.

In the UK and the Netherlands, airborne concentrations of Ambrosia pollen are usually low. However, more than 30 Ambrosia pollen grains per cubic metre of air above the level capable to trigger allergic symptoms were recorded in Leicester UK and Leiden NL on 4 and 5 September The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the episode could be the result of long distance transport, to identify the potential sources of these pollen grains and to describe the conditions that facilitated this possible long distance transport.

Airborne Ambrosia pollen data were collected at 10 sites in Europe. Back trajectories calculated at Leicester and Leiden show that higher altitude air masses m originated from source areas on the Pannonian Plain and Ukraine.

The study indicates that the Ambrosia pollen grains recorded during the episode in Leicester and Leiden were probably not produced by local sources but transported long distances from potential source regions in east Europe, i.

Ambrosia airborne pollen concentration modelling and evaluation over Europe. Native from North America, Ambrosia artemisiifolia L.

Common Ragweed is an invasive annual weed introduced in Europe in the mid-nineteenth century. It has a very high spreading potential throughout Europe and releases very allergenic pollen leading to health problems for sensitive persons.

Because of its health effects, it is necessary to develop modelling tools to be able to forecast ambrosia air pollen concentration and to inform allergy populations of allergenic threshold exceedance.

To calculate and predict airborne concentrations of ambrosia pollen, a chain of models has been built. The detailed methodology, formulations and input data will be presented. A set of simulations has been performed to simulate airborne concentrations of pollens over long time periods on a large European domain. Hindcast simulations - driven by ERA-Interim re-analyses are designed to best simulate past periods airborne pollens. The modelled pollen concentrations are calibrated with observations and validated against additional observations.

Then, year long historical simulations - are carried out using calibrated ambrosia density distribution and climate model-driven weather in order to serve as a control simulation for future scenarios. By comparison with multi-annual observed daily pollen counts we have shown that the model captures well the gross features of the pollen. Modelling the introduction and spread of non-native species: Biological invasions are a major driver of global change, for which models can attribute causes, assess impacts and guide management.

However, invasion models typically focus on spread from known introduction points or non-native distributions and ignore the transport processes by which species arrive.

Here, we developed a simulation model to understand and describe plant invasion at a continental scale, integrating repeated transport through trade pathways, unintentional release events and the population dynamics and local anthropogenic dispersal that drive subsequent spread. We used the model to simulate the invasion of Europe by common ragweed Ambrosia artemisiifolia , a globally invasive plant that causes serious harm as an aeroallergen and crop weed. Simulations starting in accurately reproduced ragweed 's current distribution, including the presence of records in climatically unsuitable areas as a result of repeated introduction.

Furthermore, the model outputs were strongly correlated with spatial and temporal patterns of ragweed pollen concentrations, which are fully independent of the calibration data.

The model suggests that recent trends for warmer summers and increased volumes of international trade have accelerated the ragweed invasion. For the latter, long distance dispersal because of trade within the invaded continent is highlighted as a key invasion process, in addition to import from the native range. Biosecurity simulations, whereby transport through trade pathways is halted, showed that effective control is only achieved by early action targeting all relevant pathways.

We conclude that invasion models would benefit from integrating introduction processes transport and release with spread dynamics, to better represent propagule pressure from native sources as well as mechanisms for long-distance dispersal within invaded continents. Ultimately, such integration may facilitate better prediction of spatial and temporal variation in invasion. Ragweed pollen production and dispersion modelling within a regional climate system, calibration and application over Europe.

Its pollen can be transported over large distances and has been recognized as a significant cause of hay fever and asthma D'Amato et al. To simulate production and dispersion of common ragweed pollen, we implement a pollen emission and transport module in the Regional Climate Model RegCM version 4 using the framework of the Community Land Model CLM version 4. In this online approach pollen emissions are calculated based on the modelling of plant distribution, pollen production, species-specific phenology, flowering probability, and flux response to meteorological conditions.

A pollen tracer model is used to describe pollen advective transport, turbulent mixing, dry and wet deposition. The model is then applied and evaluated on a European domain for the period To reduce the large uncertainties notably due to the lack of information on ragweed density distribution, a calibration based on airborne pollen observations is used.

Accordingly a cross validation is conducted and shows reasonable error and sensitivity of the calibration. Resulting simulations show that the model captures the gross features of the pollen concentrations found in Europe, and reproduce reasonably both the spatial and temporal patterns of flowering season and associated pollen concentrations measured over Europe.

The model can explain The correlation between simulated and observed daily concentrations time series reaches 0. Statistical scores show that the model performs better over the central Europe source region where pollen loads are larger and the model is better constrained.

From these simulations health risks associated to common ragweed pollen. The airborne ragweed pollen spectrum was investigated in the air of Ankara, Turkey for aperiod of ten years using a Burkard seven-day volumetric recording trap. In our study period,long distance transported Ambrosia pollen has been registered. Daily pollen levels varied from low to highin Burge's system. In last three years, the pollen concentration of Ambrosia showed a clear increasingtendency.

Our results prove that ragweed pollen may be an important threat for ragweed sensitive patientsin Ankara city in near future.

Lifescience Database Archive English. Full Text Available c Spatial and temporal variations in airborne Ambrosia pollen in Europe. The goal of the present study is to provide a baseline for spatial and temporal variations in airborne Ambrosia pollen in Europe that can be used for the management and evaluation of this noxious plant. The study covers the full range of Ambrosia artemisiifolia L.

Airborne Ambrosia pollen data for the principal flowering period of Ambrosia August-September recorded during a year period were obtained from monitoring sites. The mean sum of daily average airborne Ambrosia pollen and the number of days that Ambrosia pollen was recorded in the air were analysed.

The mean and standard deviation SD were calculated regardless of the number of years included in the study period, while trends are based on those time series with 8 or more years of data. The direction of any trends varied locally and reflected changes in sources of the pollen, either in size or in distance from the monitoring station.

Pollen monitoring is important for providing an early warning of the expansion of this invasive and noxious plant. The extraction of exotic plant ragweed Ambrosia artemisiifolia L. It can prevent the extraction of ragweed from inactivation,which could be easily caused by external condition such as illumination and temperature. The microcapsule technique can improve the property of extraction. The results showed that the morphology of microcapsules was regular and integrated observed under scanning electron microscope SEM.

Moreover,the core material was coated with shell material observed by the infrared spectrum analysis with Fourier transform infrared spectroscopy FTIR. The association efficiency and loading capacity of the microcapsules determined by ultraviolet spectrophotometer were The medium diameter was And the results of thermogravimetric analysis TGA demonstrated that the thermal stability of the microcapsules was superior to the core material.

Consequently,the microcapsules with the extraction can avoid the unstable defect of the natural extraction. In addition,the activity was also lengthened by this technique.

The occurrence of Ambrosia pollen in the atmosphere of Northwest Turkey: Ambrosia pollen was first reported as an important allergen in North America at the end of the nineteenth century, and many European countries have recently reported its increasing significance for pollen allergy. The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the studied period could be the result of long-distance transport LDT and to identify the potential sources of Ambrosia pollen grains.

The study investigates Ambrosia pollen episodes during the peak term of six yearly periods between and by examining source regions in Ambrosia pollen in Bursa, Turkey. A volumetric trap was used for collecting the pollen samples, and the back-trajectory model was used to identify a potential source of atmospheric Ambrosia pollen. The days when pollen levels exceeded 30 P m-3 were computed, and clusters were shown on the figures. The study indicates that the Ambrosia pollen grains recorded during the episode in Bursa were not produced by local sources but transported long distances from potential source regions around the Azov Sea in Russia and Ukraine, Black Sea region of Turkey, Romania, and Bulgaria.

Note that atmospheric concentrations of Ambrosia pollen exceeded the clinical threshold during 28 days during the investigation period. Taking into consideration the high allergenicity of Ambrosia pollen, the present findings suggest that the number of ragweed -sensitized individuals might increase in the near future in the region. Full Text Available From a medical perspective, introduction and spread of ragweed in Germany are a disaster.

The pollen of the species trigger allergic rhinitis and conjunctivitis that often lead to allergies against food items like celery or spices. In some cases this can lead to allergic asthma that at first appears during the ragweed pollen season in September and October, but can later prevail during the whole year.

In addition, touching the plant can result in contact dermatitis. From a medical point of view, halting the spread of ragweed is important and necessary.

Analysis of high allergenicity airborne pollen dispersion: The appearance of ragweed pollen in the air became more frequent in northerly countries. Attention of allergologists and aerobiologists in these countries is focused on the phenomenon that Ambrosia plants found relatively sporadic but the amount of pollen is high in particular days. Over the latter decade, a matter of particular concern has been Ambrosia pollen, whose appearance in the air is determined by the plants dispersing it and meteorological processes that alter pollen release, dissemination, transport or deposition on surfaces.

Pollen data used in this study were collected in three pollen-trapping sites in Lithuania. The data corresponding to years of pollen monitoring were documented graphically and evaluated statistically. Analysis of the pollen data suggests that although the number of ragweed plants identified has not increased over the latter decade, the total pollen count has been on the increase during the recent period. The highest atmospheric pollen load is established on the last days of August and first days of September.

We have established a regularity exhibiting an increase in ragweed pollen count conditioned by south-eastern winds in Lithuania. The ex-periment took ragweek as a model invader to reveal the community invisibility of different habitats. The results revealed that planting native species in bare soils, and maintaining the native communities.

Plants remember past weather: After extreme dry wet summers or years, pollen production of different taxa may decrease increase substantially. Accordingly, studying effects of current and past meteorological conditions on current pollen concentrations for different taxa have of major importance.

The purpose of this study is separating the weight of current and past weather conditions influencing current pollen productions of three taxa. Two procedures, namely multiple correlations and factor analysis with special transformation are used.

The year data sets include daily pollen counts of Ambrosia ragweed , Poaceae grasses and Populus poplar , as well as daily values of four climate variables temperature, relative humidity, global solar flux and precipitation. Multiple correlations of daily pollen counts with simultaneous values of daily meteorological variables do not show annual course for Ambrosia , but do show definite trends for Populus and Poaceae. Results received using the two methods revealed characteristic similarities.

For all the three taxa, the continental rainfall peak and additional local showers in the growing season can strengthen the weight of the current meteorological elements. However, due to the precipitation, big amount of water can be stored in the soil contributing to the effect of the past climate elements during dry periods.

Higher climate sensitivity especially water sensitivity of the herbaceous taxa Ambrosia and Poaceae can be definitely established compared to the arboreal Populus. Separation of the weight of the current and past weather conditions for different taxa involves practical importance both for health care and agricultural production.

Field and greenhouse experiments were conducted during and at Stoneville, MS to determine control of ragweed parthenium with several preemergence PRE and postemergence POST herbicides registered for use in corn, cotton, peanut, rice, and soybean.

Change in Ragweed Pollen Season, Environmental Protection Agency — This figure shows how the length of ragweed pollen season changed at 11 locations in the central United States and Canada between and Ambrosia beetles are being increasingly recognized as significant pests of field-grown ornamental nursery stock.

Two species are especially problematic in ornamental nurseries, namely the black stem borer, Xylosandrus germanus, and the granulate ambrosia beetle, Xylosandrus crassiusculus. Economic analysis of preventing introduction of ragweed in Denmark. Ragweed is an Invasive Alien Species natively growing in North America which is at risk of being introduced in Denmark thru import of bird seeds.

The plant produces a high amount of pollen which causes allergy and asthma and is considered a very potent allergy source. It is estimated that An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by Euwallacea ambrosia beetles on avocado and other plant hosts. Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea Coleoptera: Is ragweed pollen allergenicity governed by environmental conditions during plant growth and flowering?

However, how genotype and environment contribute to ragweed pollen allergenicity has still to be established. To throw some light on the factors governing allergenicity, in this work ragweed plants from three Regions Canada, France, Italy were grown in both controlled constant and standard environmental conditions seasonal changes in temperature, relative humidity and light. Pollen from single plants was characterized for its allergenic potency and for the underlying regulation mechanisms by studying the qualitative and quantitative variations of the main isoforms of the major ragweed allergen Amb a 1.

Results showed a statistically higher variability in allergenicity of pollen from standard conditions than from controlled conditions growing plants. This variability was due to differences among single plants, regardless of their origin, and was not ascribed to differences in the expression and IgE reactivity of individual Amb a 1 isoforms but rather to quantitative differences involving all the studied isoforms.

It suggests that the allergenic potency of ragweed pollen and thus the severity of ragweed pollinosis mainly depends on environmental conditions during plant growth and flowering, which regulate the total Amb a 1 content. Effects of photoperiod and temperature on reproductive diapause in Ophraella communa Coleoptera: Chrysomelidae , a potential biocontrol agent against Ambrosia artemisiifolia.

To investigate the seasonal adaptation strategies of Ophraella communa to new habitats,the effects and regulation mechanisms of photoperiod and temperature on the reproductive diapause in a population collected from Changsha,Hunan were examined. Adults showed obvious reproductive diapause,which was regulated by photoperiod and temperature. The pre-oviposition period was significantly prolonged when the pupae and adults were transferred from long-days to short-days,but the day length influence was not obvious when they were transferred only in the adult stage.

However,the fecundity dropped greatly no matter whether the photoperiod shifted to short-days only in the adult stage or whether the shift occurred in both the pupal and adult stage. The fecundity was extremely low when photoperiod shifted from long-days to short-days in both pupal and adult stages. This was an indication that the pupal and adult stages were the photoperiod-sensitive stage for adult reproductive diapause. This was especially true for the photoperiod in the pupal stage,which has a distinctly significant regulative effect on reproductive diapause.

Additionally,this article also addresses the reason for different photoperiodic response patterns in reproductive diapause induction between the Changsha strain and the Tsukuba strain Japan of O. Ragweed in France is a rather recent pollen which causes strong allergies on the populations concerned. This pollen, mainly located in the area Rhone-Alpes, extend more and more on totality of France. Indeed, the pollinic data highlight the presence of ragweed on all the territory with very low, as for Brittany, to several hundreds grains in the area of Rhone-Alpes.

So four towns of this area have followed closely the extend of this pollen during the year through five pollen-traps 2 for the town of Lyon. The trap of Lyon I Gerland made it possible to follow temporal the extend of ragweed from to and the increase of the number of grains as that of the number of days with a significant allergic risk.

The study shows also the differences in quantity of pollens, the differences between the daily allergic risks of the five sites, as well as the differences, between the cities, of the number of days when the allergic risk is significant. It is necessary that pollen of ragweed can be followed closely because of its strong allergenic capacity, in the area of Rhone-Alpes, where the plant prevails mainly, but also on the totality of the own territory, this to supervise its evolution and the speed of proliferation of the plant.

Chemical ecology and lure development for redbay ambrosia beetle. The exotic redbay ambrosia beetle, Xyleborus glabratus Eichhoff, has become a serious invasive pest in the U. Female beetles are the primary vectors of a pathogenic fungus Raffaelea lauricola that causes laurel wilt. This lethal vascular dise Ambrosia beetles associated with laurel wilt of avocado.

Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in near Savannah, Georgia. Laurel wilt has since spr The invasive redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in the U.

Redbay Ambrosia Beetle xyleborus glabratus eichoff coleoptera: The redbay ambrosia beetle, Xyleborus glabratus Eichoff, and its associated fungus Raffaelea lauricola T. Together, they cause a vascular wilt disease that is highly destructive to some species in the Lauraceae Fraedrich et al. Xyleborus glabratus is a member of the Chemical ecology of the redbay ambrosia beetle Xyleborus glabratus. The redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in the U.

Ethanol injection of ornamental trees facilitates testing insecticide efficacy against ambrosia beetles Coleoptera: Exotic ambrosia beetles are damaging pests in ornamental tree nurseries in North America.

The species Xylosandrus crassiusculus Motshulsky and Xylosandrus germanus Blandford are especially problematic. Management of these pests relies on preventive treatments of insecticides. However, field tests of recommended materials on nursery trees have been limited because of unreliable attacks by ambrosia beetles on experimental trees. Ethanol-injection of trees was used to induce colonization by ambrosia beetles to evaluate insecticides and botanical formulations for preventing attacks by ambrosia beetles.

Experiments were conducted in Ohio, Tennessee, and Virginia. Experimental trees injected with ethanol had more attacks by ambrosia beetles than uninjected control trees in all but one experiment. Xylosandrus crassiusculus and X.

In most experiments, attack rates declined 8 d after ethanol-injection. Ethanol-injection induced sufficient pressure from ambrosia beetles to evaluate the efficacy of insecticides for preventing attacks. Trunk sprays of permethrin suppressed cumulative total attacks by ambrosia beetles in most tests.

Trunk sprays of the botanical formulations Armorex and Veggie Pharm suppressed cumulative total attacks in Ohio. The bifenthrin product Onyx suppressed establishment of X. Substrate drenches and trunk sprays of neonicotinoids, or trunk sprays of anthranilic diamides or tolfenpyrad were not effective. Ethanol-injection is effective for inducing attacks and ensuring pressure by ambrosia beetles for testing insecticide efficacy on ornamental trees. Chemical ecology and serendipity: Developing attractants for Florida ambrosia beetle pests.

Two exotic ambrosia beetles have become established in southern Florida: Both pests vector pathogenic fungal symbionts; the former for laurel wilt and the latter for Fusarium dieback d Symbiont diversification in ambrosia beetles: Diversity of fungi associated with exotic scolytine beetles. In virtually every forest habitat, ambrosia beetles Coleoptera: Scolytinae, Platypodinae plant and maintain symbiotic fungus gardens inside dead or dying wood. Some introduced ambrosia beetles aggressively attack live trees and can damage tree crops, lumber, and native woody plant t In children allergic to ragweed pollen, nasal inflammation is not influenced by monosensitization or polysensitization.

In patients polysensitized to pollen allergens, the priming effect, by which the sensitivity of the nasal mucosa to an allergen is increased by the previous exposure to another allergen, is a known phenomenon.

This study was aimed at evaluating the degree of nasal inflammation, assessed by nasal cytology, in children with allergic rhinitis AR from ragweed pollen according to being monosensitized or polysensitized.

The study included 47 children. Of them, 24 suffered from AR caused by sensitization to grass pollen and ragweed pollen group A and 23 were sensitized only to ragweed pollen group B. In all patients, the severity of AR was assessed according to the Allergic Rhinitis and Its Impact on Asthma guidelines, and comorbidities were also evaluated.

In group A, No significant difference was detected in the number of the considered comorbidities between the two groups. This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico.

The designated site covers acres and contains acres of tailings and some of the original mill structures. Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile.

Another alternative which would involve moving the tailings to a new location is also assessed in this document. This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location.

The no action alternative is also assessed in this document. T-cell repertoire in the blood and lungs of atopic asthmatics before and after ragweed challenge.

T cells play a pivotal role in initiating and orchestrating allergic responses in asthma. The goal of this work was to learn whether ragweed challenge in the lungs alters the T-cell repertoire expressed in the blood and lungs of atopic asthmatics.

Analyses of cell numbers, differentials, and T-cell. Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure.

We collected a total of beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species. Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community.

Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism. Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance.

We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi host and air moisture , resulted in a favorable conditions for species accumulation of ambrosia. The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas.

Co-occurrence of Artemisia and Ambrosia pollen seasons against the background of the synoptic situations in Poland.

The Asteraceae family is one of the largest families, comprising 67 genera and species in Poland. However, only a few genera, including Artemisia and Ambrosia are potential allergenic sources. The aim of the study was to estimate how often and to what degree Artemisia and Ambrosia pollen seasons co-occur intensifying human health risk, and how synoptic situations influence frequency of days with high pollen concentrations of both taxa.

Artemisia and Ambrosia pollen data were collected, using the volumetric method, at 8 sites in Poland. Daily concentrations of Artemisia pollen equal to 30 grains or more and Ambrosia pollen equal to 10 grains or more were accepted as high values. Concentrations of more than 10 pollen grains were defined as high in the case of Ambrosia because its allergenicity is considered higher.

High concentrations were confronted with synoptic situations. Co-occurrence of Artemisia and Ambrosia pollen seasons is being found most often, when Ambrosia pollen season starts in the first half of August.

If it happens in the last 10 days of August high pollen concentrations of Artemisia and Ambrosia do not occur at the same days. The high Artemisia pollen concentrations occur, when continental or polar maritime old air masses inflow into Poland.

The impact of air masses on high Ambrosia pollen concentrations depends on site localizations. It is likely, that in the south-eastern part of Poland high Ambrosia pollen concentrations result from the pollen transport from east-south-south-westerly directions and the local sources. Co-occurrence of both taxa pollen seasons depends on the air masses inflow and appears more often in a south-eastern part of Poland.

Furthermore, we used two different meteorological data sets the global GDAS data set and from the WRF mesoscale model; the meteorological parameters were: U and V wind components, temperature and relative humidity into HYSPLIT to evaluate the influence of meteorological input on calculated trajectories for high concentration ragweed episodes.

The HYSPLIT simulations with two different meteorological inputs indicated that footprint studies on ragweed benefit from a higher resolution meteorological data sets. Suitability of California bay laurel and other species as hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetle. The redbay ambrosia beetle Xyleborus glabratus Eichhoff is a non-native vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern U.

Concern exists that X. Suitability of California bay laurel and other species as potential hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetle. The redbay ambrosia beetle Xyleborus glabratus Eichhoff is a non-native invasive forest pest and vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern United States U.

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Tradescantia virginiana leaf epidermal cells were plasmolysed by sequential treatment with 0. Plasmolysis revealed adhesion of the plasma membrane to the cell wall at sites coinciding with cytoskeletal arrays involved in the polarisation of cells undergoing asymmetric divisions--cortical actin patch--and in the establishment and maintenance of the division site--preprophase band of microtubules and filamentous F actin. The majority of cells retained adhesions at the actin patch throughout mitosis.

After the breakdown of the nuclear envelope, plasmolysis had a dramatic effect on spindle orientation, cell plate formation, and the plane of cytokinesis.

Spindles were rotated at abnormal angles including tilted into the plane of the epidermis. Cell plates formed but were quickly replaced by vacuole-like intercellular compartments containing no Tinopal-stainable cell wall material.

This compartment usually opened to the apoplast at one side, and cytokinesis was completed by the furrow extending across the protoplast. This atypical cytokinesis was facilitated by a phragmoplast containing microtubules and F-actin. Progression of the furrow was unaffected by 25 micrograms of cytochalasin B per ml but inhibited by 10 microM oryzalin. Phragmoplasts were contorted and misguided and cytokinesis prolonged, indicating severe disruption to the guidance mechanisms controlling phragmoplast expansion.

The mechanism of human T-lymphocyte activation by the pathogenic yeast Cryptococcus neoformans has not been established. Previous investigations have suggested that C. Because of the potential importance of the mechanism of T- cell activation for our understanding of the immune response to C.

The T- cell response to C. However, allogeneic cells were sufficient for accessory cell function, indicating that the response was not major histocompatibility complex restricted. The percentage of T cells in the cell cycle was higher than that with the recall antigen tetanus toxoid but lower than that with the mitogenic lectin phytohemagglutinin A or the superantigen Staphylococcus enterotoxin B.

Compared to the case for most mitogens or superantigens, the proliferative response is late and the number of T cells that enter the cell cycle and the precursor frequency are low, indicating that the mitogenic effect is modest.

However, the mitogenic effect of C. Crystal structure of MraY, an essential membrane enzyme for bacterial cell wall synthesis. MraY phospho-MurNAc-pentapeptide translocase is an integral membrane enzyme that catalyzes an essential step of bacterial cell wall biosynthesis: MraY has long been considered a promising target for the development of antibiotics, but the lack of a structure has hindered mechanistic understanding of this critical enzyme and the enzyme superfamily in general.

Single- wall carbon nanotube-based proton exchange membrane assembly for hydrogen fuel cells. A membrane electrode assembly MEA for hydrogen fuel cells has been fabricated using single- walled carbon nanotubes SWCNTs support and platinum catalyst. Scanning electron microscopy and Raman spectroscopy showed that the nanotubes and the platinum retained their nanostructure morphology on the carbon fiber surface. Electrochemical impedance spectroscopy EIS revealed that the carbon nanotube-based electrodes exhibited an order of magnitude lower charge-transfer reaction resistance R ct for the hydrogen evolution reaction HER than did the commercial carbon black CB -based electrodes.

Relative contribution of the cell wall , cytoplasmic membrane , and cytoplasm to the gram-positive characteristic of Bacillus megaterium. Protoplasts of Bacillus megaterium were confirmed as being gram-negative, as reported by Gerhardt et al. Bacterial strains living in the environment must cope with the toxic compounds originating from humans production. Surface bacterial structures, cell wall and cytoplasmic membrane , surround each bacterial cell and create selective barriers between the cell interior and the outside world.

They are a first site of contact between the cell and toxic compounds. Organic pollutants are able to penetrate into cytoplasmic membrane and affect membrane physiological functions. Bacteria had to evolve adaptation mechanisms to counteract the damage originated from toxic contaminants and to prevent their accumulation in cell.

This review deals with various adaptation mechanisms of bacterial cell concerning primarily the changes in cytoplasmic membrane and cell wall. Low energy consumption of cell adaptation is required to provide other physiological functions.

Bacteria able to survive in toxic environment could help us to clean contaminated areas when they are used in bioremediation technologies. Proteomics of plasma membranes from poplar trees reveals tissue distribution of transporters, receptors, and proteins in cell wall formation.

ATP-binding cassette transporters all members of subfamilies B, C, and G and receptor-like kinases four subfamilies were two of the largest protein families found, and the members of these two families showed pronounced tissue distribution. Leaf plasma membranes were characterized by a very high proportion of transporters, constituting almost half of the integral proteins. Proteins involved in cell wall synthesis such as cellulose and sucrose synthases and membrane trafficking were most abundant in xylem plasma membranes in agreement with the role of the xylem in wood formation.

Twenty-five integral proteins and 83 soluble proteins were exclusively found in xylem plasma membranes , which identifies new candidates associated with cell wall synthesis and wood formation.

Among the proteins uniquely found in xylem plasma membranes were most of the enzymes involved in lignin biosynthesis, which suggests that they may exist as a complex linked to the plasma membrane.

A laser microsurgical method of cell wall removal allows detection of large-conductance ion channels in the guard cell plasma membrane. Application of patch clamp techniques to higher-plant cells has been subject to the limitation that the requisite contact of the patch electrode with the cell membrane necessitates prior enzymatic removal of the plant cell wall.

Because the wall is an integral component of plant cells , and because cell-wall -degrading enzymes can disrupt membrane properties, such enzymatic treatments may alter ion channel behavior.

We compared ion channel activity in enzymatically isolated protoplasts of Vicia faba guard cells with that found in membranes exposed by a laser microsurgical technique in which only a tiny portion of the cell wall is removed while the rest of the cell remains intact within its tissue environment. These data indicate that ion channels are present in plant membranes that are not detected by conventional patch clamp techniques involving the production of individual plant protoplasts isolated from their tissue environment by enzymatic digestion of the cell wall.

Given the large conductances of the channels revealed by laser-assisted patch clamping, we hypothesize that these channels play a significant role in the regulation of ion content and electrical signalling in guard cells. Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown.

Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis Arabidopsis thaliana , are disrupted by the RGD arginine-glycine-aspartic acid tripeptide sequence, a characteristic cell adhesion motif in mammals. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis.

Moreover, the two peptides also disrupted cell wall -plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides. Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain.

The lectin domain of one of these, At5g, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces.

Lectin receptor kinases participate in protein-protein interactions to mediate plasma membrane-cell wall adhesions in Arabidopsis. High affinity RGD-binding sites at the plasma membrane of Arabidopsis thaliana links the cell wall.

The heptapeptide Tyr-Gly-Arg-Gly-Asp-Ser-Pro containing the sequence Arg-Gly-Asp RGD--the essential structure recognised by animal cells in substrate adhesion molecules was tested on epidermal cells of onion and cultured cells of Arabidopsis upon plasmolysis. Dramatic changes were observed on both types of cells following treatment: Protoplasts isolated from Arabidopsis cells agglutinate in the presence of ProNectinF, a genetically engineered protein of 72 kDa containing 13 RGD sequences: The addition of the RGD-heptapeptide disrupted the adhesion between the protoplasts.

Purified plasma membrane from Arabidopsis cells exhibits specific binding sites for the iodinated RGD-heptapeptide. The binding is saturable, reversible, and two types of high affinity sites Kd1 approximately 1 nM, and Kd2 approximately 40 nM can be discerned. Competitive inhibition by several structurally related peptides and proteins noted the specific requirement for the RGD sequence.

Thus, the RGD-binding activity of Arabidopsis fulfils the adhesion features of integrins, i. Cell wall accumulation of fluorescent proteins derived from a trans-Golgi cisternal membrane marker and paramural bodies in interdigitated Arabidopsis leaf epidermal cells. In most dicotyledonous plants, leaf epidermal pavement cells develop jigsaw puzzle-like shapes during cell expansion.

Therefore, visualization of membrane trafficking in leaf pavement cells should contribute an understanding of the mechanism of plant cell morphogenesis.

To reveal membrane trafficking in pavement cells , we observed monomeric red fluorescent protein-tagged rat sialyl transferases, which are markers of trans-Golgi cisternal membranes , in the leaf epidermis of Arabidopsis thaliana. Quantitative fluorescence imaging techniques and immunoelectron microscopic observations revealed that accumulation of the red fluorescent protein occurred mostly in the curved regions of pavement cell borders and guard cell ends during leaf expansion.

Transmission electron microscopy observations revealed that apoplastic vesicular membrane structures called paramural bodies were more frequent beneath the curved cell wall regions of interdigitated pavement cells and guard cell ends in young leaf epidermis. In addition, pharmacological studies showed that perturbations in membrane trafficking resulted in simple cell shapes.

These results suggested possible heterogeneity of the curved regions of plasma membranes , implying a relationship with pavement cell morphogenesis. An enzyme complex responsible for the TUA chain biosynthesis was purified and characterized. TUAS displays hydrophobic properties and is found primarily associated with the cytoplasmic membrane. The purified TUAS contains carotinoids and lipids. TUAS activity is diminished by phospholipase digestion.

We propose that TUAS serves as a multitasking polysaccharide assembling station on the bacterial membrane. Actin filaments regulate the adhesion between the plasma membrane and the cell wall of tobacco guard cells. During the opening and closing of stomata, guard cells undergo rapid and reversible changes in their volume and shape, which affects the adhesion of the plasma membrane PM to the cell wall CW. The dynamics of actin filaments in guard cells are involved in stomatal movement by regulating structural changes and intracellular signaling.

However, it is unclear whether actin dynamics regulate the adhesion of the PM to the CW. In this study, we investigated the relationship between actin dynamics and PM-CW adhesion by the hyperosmotic-induced plasmolysis of tobacco guard cells. We found that actin filaments in guard cells were depolymerized during mannitol-induced plasmolysis.

However, treatment with latrunculin B alleviated the RGDS peptide-induced plasmolysis and endocytosis. Our results reveal that the actin depolymerization is involved in the regulation of the PW-CW adhesion during hyperosmotic-induced plasmolysis in tobacco guard cells. In this study, a series of nanocomposite membranes were fabricated with the PVA-influenced functionalized MWCNTs reinforced into the Nafion polymer matrix by a solution casting method.

After that, the nanocomposite membranes were characterized by thermo-gravimetric analysis TGA to observe the thermal enhancement caused by effective cross-linking between the f-MWCNTs with the composite polymer matrixes. Diffusion of nitric oxide across cell membranes of the vascular wall requires specific connexin-based channels.

NO is generated within cells and frequently must be transferred to responsive neighboring cells , as occurs in the endothelium-dependent relaxation of smooth muscle cells observed in blood vessels.

It is thought that NO diffuses freely across cell membranes , but it may also permeate through low resistant membrane pathways. Here, we describe the participation of connexin Cx -formed channels in the NO transport across cell membranes and between endothelial and smooth muscle cells.

We used a water-soluble NO donor of high molecular weight S-nitrosylated albumin, BSA-NO that does not permeate through cell membranes or Cx-based channels and the NO-sensitive dye 4,5-diaminofluorescein diacetate to detect changes of intracellular NO concentration. We found that NO generated in the extracellular space was not detected intracellularly in Cx-deficient HeLa cells , suggesting that cell membrane represents a significant diffusion barrier for NO transfer.

In contrast, NO closed hemichannels of HeLa-Cx32 cells , which otherwise are permeable to NO if are opened by a divalent cation-free extracellular solution. Consistent with this, blockade of Cx-based channels abolished the myoendothelial NO transfer and associated NO-dependent vasodilation induced by acethylcholine.

These results indicate that Cx-based channels play a key role in the NO-dependent tonic control of vascular function and may direct the NO signal to specific targets, which provides a novel mechanistic basis for the critical role of Cxs in cell-cell communication in the vessel wall. Perturbation of the Staphylococcus aureus cytoplasmic membrane CM is felt to play a key role in the microbicidal mechanism of many antimicrobial peptides APs. We hypothesized that the relationships between MP and killing may differ for distinct APs.

Four APs with different structure-activity relationships were examined: MP was quantified fluorometrically by calcein release. All APs tested, except polymyxin B, caused concentration-dependent MP and killing of whole cells , but not of protoplasts. The reduced AP susceptibility of protoplasts was associated with increased cardiolipin and lysyl-phosphatidylglycerol content and reduced fluidity of their CMs. Collectively, these results indicate that i structurally distinct APs likely exert their staphylocidal effects by differing mechanisms, ii MP is not the sole event leading to AP-induced staphylocidal activity, iii a complex interrelationship exists between the CM and CW in AP-induced killing, and iv liposomes modeled upon whole cell or protoplast CMs can recapitulate the respective susceptibilities to killing by distinct APs.

Peptidoglycan is the major component of the cell envelope of virtually all bacteria. It has structural roles and acts as a selective sieve for molecules from the outer environment. Peptidoglycan synthesis is therefore one of the most important biogenesis pathways in bacteria and has been studied extensively over the last twenty years. The pathway starts in the cytoplasm, continues in the cytoplasmic membrane and finishes in the periplasmic space, where the precursor is polymerized into the peptidoglycan layer.

A number of proteins involved in this pathway, such as the Mur enzymes and the penicillin binding proteins PBPs , have been studied and regarded as good targets for antibiotics. The present review focuses on the membrane steps of peptidoglycan synthesis that involve two enzymes, MraY and MurG, the inhibitors of these enzymes and the inhibition mechanisms. We also discuss the challenges of targeting these two cytoplasmic membrane associated proteins in bacterial cells and the perspectives on how to overcome the issues.

Knockout of the alanine racemase gene in Aeromonas hydrophila HBNUAh01 results in cell wall damage and enhanced membrane permeability. This study focused on the alanine racemase gene alr-2 , which is involved in the synthesis of d-alanine that forms the backbone of the cell wall. When the mutant was supplemented with d-alanine, growth was unaffected; deprivation of d-alanine caused the growth arrest of the starved mutant cells , but not cell lysis.

No alanine racemase activity was detected in the culture of the mutant. Additionally, a membrane permeability assay showed increasing damage to the cell wall during d-alanine starvation. No such damage was observed in the wild type during culture. Scanning and transmission electron microscopy analyses revealed deficiencies of the cell envelope and perforation of the cell wall. Leakage of UV-absorbing substances from the mutants was also observed. Thus, the partial viability of the mutants and their independence of d-alanine for growth indicated that inactivation of alr-2 does not impose an auxotrophic requirement for d-alanine.

Effect of chirality and length on the penetrability of single- walled carbon nanotubes into lipid bilayer cell membranes. The ability of carbon nanotubes to enter the cell membrane acting as drug-delivery vehicles has yielded a plethora of experimental investigations, mostly with inconclusive results because of the wide spectra of carbon nanotube structures. Because of the virtual impossibility of synthesizing CNTs with distinct chirality, we report a parametric study on the use of molecular dynamics to provide better insight into the effect of the carbon nanotube chirality and the aspect ratio on the interaction with a lipid bilayer membrane.

The simulation results indicated that a single- walled carbon nanotube utilizes different time-evolving mechanisms to facilitate their internalization within the membrane. These mechanisms comprise both penetration and endocytosis. It was observed that carbon nanotubes with higher aspect ratios penetrate the membrane faster whereas shorter nanotubes undergo significant rotation during the final stages of endocytosis.

Furthermore, nanotubes with lower chiral indices developed significant adhesion with the membrane. This adhesion is hypothesized to consume some of the carbon nanotube energy, thus resulting in longer times for the nanotube to translocate through the membrane. Combined effect of synthetic enterocin CRL35 with cell wall , membrane -acting antibiotics and muranolytic enzymes against Listeria cells.

To evaluate the inhibition effectiveness of enterocin CRL35 in combination with cell wall , membrane -acting antibiotics and muranolytic enzymes against the foodborne pathogen Listeria. Synthetic enterocin CRL35 alone and in combination with monensin, bacitracin, gramicidin, mutanolysin and lysozyme were used in this study. Antibiotics showed positive interactions with the bacteriocin in both strains tested.

On the other hand, when mutanolysin and enterocin CRL35 were added to resting cells in a buffer system, the lytic effect of mutanolysin was enhanced.

However, the addition of mutanolysin showed no effect on the growth of L. Moreover, mutanolysin allowed the overgrowth of L. Based on our results, we conclude that the combination of synthetic enterocin CRL35 with some antibiotics is effective against L. The effectiveness of the combination of synthetic enterocin CRL35 with muramidases seems to depend on complex environments, and more detailed studies need to be performed to elucidate this issue.

Enterocin CRL35 represents a promising agent that not only can ensure the quality and safety of food but it can also be combined with several antimicrobial agents important in the medical field. Deciphering the Metabolism of Undecaprenyl-Phosphate: During the biogenesis of bacterial cell-wall polysaccharides, such as peptidoglycan, cytoplasmic synthesized precursors should be trafficked across the plasma membrane.

This essential process requires a dedicated lipid, undecaprenyl-phosphate that is used as a glycan lipid carrier. The sugar is linked to the lipid carrier at the inner face of the membrane and is translocated toward the periplasm, where the glycan moiety is transferred to the growing polymer.

Undecaprenyl-phosphate originates from the dephosphorylation of its precursor undecaprenyl-diphosphate, with itself generated by de novo synthesis or by recycling after the final glycan transfer.

Undecaprenyl-diphosphate is de novo synthesized by the cytosolic cis-prenyltransferase undecaprenyl-diphosphate synthase, which has been structurally and mechanistically characterized in great detail highlighting the condensation process. In contrast, the next step toward the formation of the lipid carrier, the dephosphorylation step, which has been overlooked for many years, has only started revealing surprising features. In contrast to the previous step, two unrelated families of integral membrane proteins exhibit undecaprenyl-diphosphate phosphatase activity: BacA and members of the phosphatidic acid phosphatase type 2 super-family, raising the question of the significance of this multiplicity.

Moreover, these enzymes establish an unexpected link between the synthesis of bacterial cell-wall polymers and other biological processes. In the present review, the current knowledge in the field of the bacterial lipid carrier, its mechanism of action, biogenesis, recycling, regulation, and future perspective works are presented.

Plants are able to generate large leaf surfaces that act as two-dimensional solar panels with a minimum investment in building material, thanks to a hydrostatic skeleton. This requires high intracellular pressures up to 1 MPa , which depend on the presence of strong cell walls. The walls of growing cells also called primary walls , are remarkably able to reconcile extreme tensile strength up to MPa with the extensibility necessary for growth. All walled organisms are confronted with this dilemma - the need to balance strength and extensibility - and bacteria, fungi and plants have evolved independent solutions to cope.

In this Primer, we discuss how plant cells have solved this problem, allowing them to support often very large increases in volume and to develop a broad variety of shapes Figure 1A,B,D. This shape variation reflects the targeted deposition of wall material combined with local variations in cell-wall extensibility, processes that remain incompletely understood. Once the cell has reached its final size, it can lay down secondary wall layers, the composition and architecture of which are optimized to exert specific functions in different cell types Figure 1E-G.

Specialized secondary walls , such as those constituting seed mucilage, are stored in a dehydrated form in seedcoat epidermis cells and show rapid swelling upon hydration of the seed.

Other walls , in particular in reserve tissues, can accommodate large amounts of storage polysaccharides, which can be easily mobilized as a carbon source. Physiological and transcriptional responses of Saccharomyces cerevisiae to d-limonene show changes to the cell wall but not to the plasma membrane. Monoterpenes can, upon hydrogenation, be used as light-fraction components of sustainable aviation fuels. Fermentative production of monoterpenes in engineered microorganisms, such as Saccharomyces cerevisiae, has gained attention as a potential route to deliver these next-generation fuels from renewable biomass.

However, end product toxicity presents a formidable problem for microbial synthesis. Due to their hydrophobicity, monoterpene inhibition has long been attributed to membrane interference, but the molecular mechanism remains largely unsolved. We found no alterations in membrane fluidity, structural membrane integrity, or fatty acid composition after the solvent challenge. A 4-fold increase in the mean fluorescence intensity per cell using calcofluor white stain and increased sensitivity to cell wall -degrading enzymes demonstrated that limonene disrupts cell wall properties.

Global transcript measurements confirmed the membrane integrity observations by showing no upregulation of ergosterol or fatty acid biosynthesis pathways, which are commonly overexpressed in yeast to reinforce membrane rigidity during ethanol exposure.

This is the first report demonstrating that cell wall , rather than plasma membrane , deterioration is the main source of monoterpene inhibition. We show that limonene can alter the structure and function of the cell wall , which has a clear effect on cytokinesis. Proteins in the cell wall and membrane of Cryptococcus neoformans stimulate lymphocytes from both adults and fetal cord blood to proliferate.

Cryptococcus neoformans is an encapsulated yeast that infects patients who have defective cell -mediated immunity, including AIDS, but rarely infects individuals who have intact cell -mediated immunity. Studies of the immune response to C.

The goal of this study was to separate C. The lymphocyte response to fungal culture medium, whole organisms, disrupted organisms, and the yeast intracellular fraction or cell wall and membrane was studied by determining thymidine incorporation and by determining the number of lymphocytes at various times after stimulation.

The cell wall and membrane of C. The optimal response occurred on day 7 of incubation, with 4 x 10 5 peripheral blood mononuclear cells per well and with 13 microg of cryptococcal protein per ml. The number of lymphocytes increased with time in culture, indicating that thymidine incorporation was accompanied by proliferation.

Proteinase K treatment of the cell wall and membrane abrogated lymphocyte proliferation, indicating that the molecule was a protein. At least 18 discrete bands were resolved from the cell wall and membrane. Since a large percentage of healthy adults responded to the cryptococcal cell wall and membrane , a mitogenic effect was investigated by testing proliferation of fetal cord blood. An investigation into plasmolysis in the oomycete Achlya bisexualis reveals that membrane-wall attachment points are sensitive to peptides containing the sequence RGD and that cell wall deposition can occur despite retraction of the protoplast.

The structure and function of membrane-wall attachment sites in walled cells , and how these relate to animal focal adhesions, is an area that is poorly understood. In view of this, we investigated how membrane-wall attachments that form upon plasmolysis, respond to peptides that disrupt animal focal adhesions. The degree of cytoplasmic disruption during plasmolysis was also investigated. Upon hyperosmotic challenge, the protoplast in hyphae of the oomycete Achlya bisexualis typically retracted incompletely due to membrane-wall attachments.

The inclusion, in the plasmolysing solution, of peptides containing the sequence RGD disrupted these attachments in a dose-dependent manner. In some hyphae, protoplast retraction stopped temporarily at attachment points - upon resumption of retraction, material was left that traced the outline of the static protoplast. Staining of this material with fluorescence brightener indicated the presence of cellulose, which suggests that wall deposition was able to occur despite plasmolysis.

The F-actin cytoskeleton was disrupted during plasmolysis; peripheral F-actin staining was observed, but there was no distinct F-actin cap; staining was more diffuse; and there were fewer plaques compared with nonplasmolysed hyphae. Our data indicate that membrane-wall attachment points are sensitive to RGD-containing peptides and that wall deposition continues despite protoplast retraction and F-actin disruption. Genome-wide reprogramming of regulatory networks, transport, cell wall and membrane biogenesis during arbuscular mycorrhizal symbiosis in Lotus japonicus.

As a consequence of the fungal colonization and of the deep reorganization shown by arbusculated cells , important impacts on root transcriptome are expected. Induction of a subset 24 genes of these was tested and confirmed by qRT-PCR, and transcript location in arbusculated cells was demonstrated for seven genes using laser-dissected cells. Improving the electro-transformation efficiency of Corynebacterium glutamicum by weakening its cell wall and increasing the cytoplasmic membrane fluidity.

To improve the transformation efficiency of Corynebacterium glutamicum cells with heterogenous plasmid DNA and single-strand DNA ssDNA using a methodology based on electro-transformation.

A semicomplex hypertonic medium was selected with addition of glycine and DL-threonine to weaken cell walls and addition of Tween 80 and isonicotinic acid hydrazide to increase cytoplasmic membrane fluidity. Their contents were optimized by response surface methodology. Cell growth, electro-transformation buffer, and transformation protocol were also optimized.

Temporary heating inactivation of the host restriction enzyme showed a significant effect. Finally, a high transformation efficiency of 3. The results shed light on the application in functional genomics and genome editing of C.

The rice dynamin-related protein DRP2B mediates membrane trafficking, and thereby plays a critical role in secondary cell wall cellulose biosynthesis. Membrane trafficking between the plasma membrane PM and intracellular compartments is an important process that regulates the deposition and metabolism of cell wall polysaccharides.

Dynamin-related proteins DRPs , which function in membrane tubulation and vesiculation are closely associated with cell wall biogenesis. However, the molecular mechanisms by which DRPs participate in cell wall formation are poorly understood. Consistent with the expression of BC3 in mechanical tissues, the bc3 mutation reduces mechanical strength, which results from decreased cellulose content and altered secondary wall structure.

Subcellular localization of fluorescence-tagged OsDRP2B and several compartment markers in protoplast cells showed that this protein not only lies at the PM and the clathrin-mediated vesicles, but also is targeted to the trans-Golgi network TGN. An FM uptake assay in transgenic plants that express green fluorescent protein-tagged OsDRP2B verified its involvement in an endocytic pathway. All of these findings lead us to conclude that OsDRP2B participates in the endocytic pathway, probably as well as in post-Golgi membrane trafficking.

Mutation of OsDRP2B disturbs the membrane trafficking that is essential for normal cellulose biosynthesis of the secondary cell wall , thereby leading to inferior mechanical properties in rice plants. Enzymatic biofuel cells EBFCs utilize enzymes to convert chemical energy present in renewable biofuels into electrical energy and have shown much promise in the continuous powering of implantable devices.

Currently, however, EBFCs are greatly limited in terms of power and operational stability with a majority of reported improvements requiring the inclusion of potentially toxic and unstable electron transfer mediators or multicompartment systems separated by a semipermeable membrane resulting in complicated setups.

Glucose oxidase and bilirubin oxidase were physically adsorbed onto these electrodes to form anodes and cathodes, respectively, and the EBFC produced power densities up to 0. Further, the electrodes were rejuvenated by a simple wash and reloading procedure. We postulate these porous and ultrahigh surface area electrodes will be useful for biosensing applications, and will allow reuse of EBFCs. In this study the elastic spring constant of the yeast cell wall is probed with the atomic force microscope AFM under variable conditions.

Cells were sequentially analyzed in rich growth medium YPD , a 0. Cells in late log phase, which have variable diameters within three to five microns, were immobilized on a patterned silicon substrate with holes approximately 3.

Force curves were taken moving laterally across the cell in one dimension after exposure to each medium. Spring constants of the cells , calculated from force curves, displayed a positional dependency and marked differences in high osmolarity medium and after the injection of sodium azide. This study demonstrates the ability of the AFM to investigate changes in cell morphology and correlate those findings to underlying physiological processes.

The Lamportian cell wall. The Lamportian Warp-Weft hypothesis suggests a cellulose-extensin interpenetrating network where extensin mechanically couples the load-bearing cellulose microfibrils in a wall matrix that is best described as a microcomposite. This model is based on data gathered from the extensin-rich walls of tomato and sycamore cell suspension culture, wherein extensin precursors are insolubilized into the wall by undefined crosslinks.

The authors recent work with cell walls isolated from intact tissue as well as walls from suspension cultured cells of the graminaceous monocots maize and rice, the non-graminaceous monocot asparagus, the primitive herbaceous dicot sugar beet, and the gymnosperm Douglas Fir indicate that although extensins are ubiquitous to all plant species examined, they are not the major structural protein component of most walls examined.

Clearly, structural wall protein alternatives to extensin exist and any cell wall model must take that into account. If we assume that extracellular matrices are a priori network structures, then new Hypless' structural proteins in the maize cell wall raise questions about the sort of network these proteins create: An electrochemical impedance spectroscopy study of polymer electrolyte membrane fuel cells electrocatalyst single wall carbon nanohorns-supported. Additionally, as-prepared and oxidized SWNH Pt-supports were compared with conventional carbon black.

Two different oxidizing treatments were considered: Both oxidizing treatments increased SWNH surface area; oxygen treatment increased surface area 4 times while acid treatment increased 2. The increase in surface area should be related to the opening access to the inner tube of SWNH.

On the other hand, the oxygen treated SWNH sample allowed to obtain the highest electrocatalyst load. Moreover, EIS analysis indicated that the major improvement in performance is related to the cathode kinetics in the as-prepared SWNH sample, while concerning the oxidized SWNH sample, the improvements are related to the electrokinetics in both anode and cathode electrodes.

These improvements should be related with differences in the hydrophobic character between SWNH and carbon black. Lipoprotein cofactors located in the outer membrane activate bacterial cell wall polymerases. Most bacteria surround themselves with a peptidoglycan PG exoskeleton synthesized by polysaccharide polymerases called penicillin-binding proteins PBPs.

Because they are the targets of penicillin and related antibiotics, the structure and biochemical functions of the PBPs have been extensively studied. Overall, our results indicate that PBP accessory proteins play a central role in PG biogenesis, and like the PBPs they work with, these factors are attractive targets for antibiotic development. Stabilization of glucose-C in microbial cell membranes PLFA and cell walls amino sugars evaluated by 13C-labelling in a field experiment.

Microorganisms control carbon C cycle and strongly contribute to formation of soil organic matter. Strong differences in the turnover of microbial groups and cellular compounds complicate the assessment of their contribution to microbial food webs and C sequestration in soil in situ. The uptake and incorporation of 13C labeled glucose by microbial groups were traced during 50 days after the labeling under field conditions. This allowed tracing C in microbial groups as well as cellular compounds.

Such long cytosol MRT depends on its heterogeneous composition, which includes high and low molecular weight organics. Amino sugars were mainly originated from microbial residues and thus, observation periods higher than 1 year are required for estimation of their MRT.

Relative 13C incorporation into amino sugars of living microorganisms showed only 0. Therefore, the turnover of cell membrane components is two times faster than that of cell walls , even in living microorganisms. Consequently, bacteria contribute more to the decomposition of low molecular weight organics, whereas fungi consume bacterial products or necromass and contribute more to long-term C stabilisation.

Thus, tracing of 13C in cellular. Hydroxylation of multi- walled carbon nanotubes: Enhanced biocompatibility through reduction of oxidative stress initiated cell membrane damage, cell cycle arrestment and extrinsic apoptotic pathway. Modification of CNTs with hydroxyl group promotes their applications in biomedical area.

However, the impact of hydroxylation on their biocompatibility is far from being completely understood. More interestingly, MWCNTs-OH exhibited significantly lower tendency to activate caspase-8, a key molecule involved in the extrinsic apoptotic pathway. Arabidopsis NDR1 is an integrin-like protein with a role in fluid loss and plasma membrane-cell wall adhesion. Whereas the genetic requirement for NDR1 in plant disease resistance signaling has been detailed, our study focuses on determining a global, physiological role for NDR1.

Specific protein motifs also point to a degree of homology with mammalian integrins, well-characterized proteins involved in adhesion and signaling.

This structural homology led us to examine a physiological role for NDR1 in preventing fluid loss and maintaining cell integrity through plasma membrane-cell wall adhesions. Our results show a substantial alteration in induced i. As an extension of these analyses, using a combination of genetic and cell biology-based approaches, we have identified a role for NDR1 in mediating plasma membrane-cell wall adhesions. Taken together, our data point to a broad role for NDR1 both in mediating primary cellular functions in Arabidopsis through maintaining the integrity of the cell wall -plasma membrane connection and as a key signaling component of these responses during pathogen infection.

Fungal cell wall organization and biosynthesis. The composition and organization of the cell walls from Saccharomyces cerevisiae, Candida albicans, Aspergillus fumigatus, Schizosaccharomyces pombe, Neurospora crassa, and Cryptococcus neoformans are compared and contrasted.

A comparison of these cell walls shows that there is a great deal of variability in fungal cell wall composition and organization. However, in all cases, the cell wall components are cross-linked together to generate a cell wall matrix. The biosynthesis and properties of each of the major cell wall components are discussed.

The chitin and glucans are synthesized and extruded into the cell wall space by plasma membrane -associated chitin synthases and glucan synthases. The glycoproteins are synthesized by ER-associated ribosomes and pass through the canonical secretory pathway. Over half of the major cell wall proteins are modified by the addition of a glycosylphosphatidylinositol anchor.

The cell wall glycoproteins are also modified by the addition of O-linked oligosaccharides, and their N-linked oligosaccharides are extensively modified during their passage through the secretory pathway. These cell wall glycoprotein posttranslational modifications are essential for cross-linking the proteins into the cell wall matrix.

Cross-linking the cell wall components together is essential for cell wall integrity. The activities of four groups of cross-linking enzymes are discussed. Cell wall proteins function as cross-linking enzymes, structural elements, adhesins, and environmental stress sensors and protect the cell from environmental changes. Cell wall proteins are essential constituents of plant cell walls ; they are involved in modifications of cell wall components, wall structure, signaling and interactions with plasma membrane proteins at the cell surface.

The application of proteomic approaches to the cell wall compartment raises important questions: What kinds of proteins can be found in Arabidopsis walls? Are some of them unexpected? What sort of post-translational modifications have been characterized in cell wall proteins to date? The purpose of this review is to discuss the experimental results obtained to date using proteomics, as well as some of the new questions challenging future research.

Mechanism of anchoring of OmpA protein to the cell wall peptidoglycan of the gram-negative bacterial outer membrane. The outer membrane protein A OmpA plays important roles in anchoring of the outer membrane to the bacterial cell wall.

However, there is a paucity of information on the structural aspects of the mechanism of PGN recognition by OmpA-like domains. To elucidate this molecular recognition process, we solved the high-resolution crystal structure of an OmpA-like domain from Acinetobacter baumannii bound to diaminopimelate DAP , a unique bacterial amino acid from the PGN. These structural data provide a detailed glimpse of how the anchoring of OmpA to the cell wall of gram-negative bacteria takes place in a DAP-dependent manner.

The pit membrane PM is a primary cell wall barrier that separates adjacent xylem water conduits, limiting the spread of xylem-localized pathogens and air embolisms from one conduit to the next.

This paper provides a characterization of the size of the pores in the PMs of grapevine Vitis vinifera. Stems were infused with pressurized water and flow rates were determined; gold particles of known size were introduced with the water to assist in determining the size of PM pores. The possibility that cell wall -degrading enzymes could alter the pore sizes, thus facilitating the ability of X.

Two cell wall -degrading enzymes likely to be produced by X. Scanning electron microscopy of control and enzyme-infused stem segments revealed that the combination of enzymes opened holes in PMs, probably explaining enzyme impacts on PMP and how a small X. Cell wall -degrading enzymes enlarge the pore size of intervessel pit membranes in healthy and Xylella fastidiosa-infected grapevines. The effect of introducing trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid CDTA , oligogalacturonides, and polygalacturonic acid into stems on water flux via the xylem was also measured.

Mechanism of action of Spanish oregano, Chinese cinnamon, and savory essential oils against cell membranes and walls of Escherichia coli O H7 and Listeria monocytogenes. The mechanism of the antimicrobial action of Spanish oregano Corydothymus capitatus , Chinese cinnamon Cinnamomum cassia , and savory Satureja montana essential oils against cell membranes and walls of bacteria was studied by the measurement of the intracellular pH and ATP concentration, the release of cell constituents, and the electronic microscopy observations of the cells when these essential oils at their MICs were in contact with Escherichia coli O Treatment with these essential oils at their MICs affected the membrane integrity of bacteria and induced depletion of the intracellular ATP concentration.

Spanish oregano and savory essential oils, however, induced more depletion than Chinese cinnamon oil. An increase of the extracellular ATP concentration was observed only when Spanish oregano and savory oils were in contact with E. Also, a significantly higher P cell constituent release was observed in the supernatant when E.

Chinese cinnamon oil was more effective to reduce significantly the intracellular pH of E. H7, whereas Chinese cinnamon and Spanish oregano decreased more significantly the intracellular pH of L.

Electronic microscopy observations revealed that the cell membrane of both treated bacteria was significantly damaged. These results suggest that the cytoplasmic membrane is involved in the toxic action of essential oils. In chemical terms, wood is best defined as a three-dimensional biopolymer composite composed of an interconnected network of cellulose, hemicelluloses, and lignin with minor amounts of extractives and inorganics.

The major chemical component of a living tree is water, but on a dryweight basis, all wood cell walls consist mainly of sugar-based polymers carbohydrates, Bacterial Cell Wall Components. Bacterial cell -surface polysaccharides cells are surrounded by a variety of cell -surface structures that allow them to thrive in extreme environments.

Components of the cell envelope and extracellular matrix are responsible for providing the cells with structural support, mediating intercellular communication, allowing the cells to move or to adhere to surfaces, protecting the cells from attack by antibiotics or the immune system, and facilitating the uptake of nutrients.

Some of the most important cell wall components are polysaccharide structures. This review discusses the occurrence, structure, function, and biosynthesis of the most prevalent bacterial cell surface polysaccharides: The roles of these polysaccharides in medicine, both as drug targets and as therapeutic agents, are also described.

Isolation of plant cell wall proteins. The quality of a proteomic analysis of a cell compartment strongly depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific drawbacks: Three categories of CWP are distinguished: Two alternative protocols are decribed for cell wall proteomics: These protocols give very low levels of contamination by intracellular proteins.

Their application should lead to a realistic view of the cell wall proteome at least for labile and weakly bound CWP extractable by salts. Cell Wall Assembly in Fucus Zygotes. Fertilization triggers the assembly of a cell wall around the egg cell of three brown algae, Fucus vesiculosus, F. New polysaccharide polymers are continually being added to the cell wall during the first 24 hours of synchronous embryo development. This wall assembly involves the extracellular deposition of fibrillar material by cytoplasmic vesicles fusing with the plasma membrane.

One hour after fertilization a fragmented wall can be isolated free of cytoplasm and contains equal amounts of cellulose and alginic acid with no fucose-containing polymers fucans present. Birefringence of the wall caused by oriented cellulose microfibrils is not detected in all zygotes until 4 hours, at which time intact cell walls can be isolated that retain the shape of the zygote.

These walls have a relatively low ratio of fucose to xylose and little sulfate when compared to walls from older embryos. When extracts of walls from 4-hour zygotes are subjected to cellulose acetate electrophoresis at pH 7, a single fucan F1 can be detected. By 12 hours, purified cell walls are composed of fucans containing a relatively high ratio of fucose to xylose and high levels of sulfate, and contain a second fucan F2 which is electrophoretically distinct from F1.

F2 appears to be deposited in only a localized region of the wall , that which elongates to form the rhizoid cell. Throughout wall assembly, the polyuronide block co-polymer alginic acid did not significantly vary its mannuronic M to guluronic G acid ratio 0.

From 6 to 24 hours of embryo development, the proportion of the major polysaccharide components found in purified walls is stable. During the extracellular assembly of this wall , the intracellular levels of the storage glucan laminaran. Two bean cell wall proteins more abundant during water deficit are high in proline and interact with a plasma membrane protein. Two antigenically related glycoproteins, called p33 and p36, accumulate in the soluble fraction of the cell wall in response to water deficit in Phaseolus vulgaris.

In this report, we show that p33 and p36 are able to adhere to leaf protoplasts, and that they bind to plasma membrane PM vesicles in a divalent cation-dependent manner. Binding assays demonstrate that both proteins specifically bind to an 80 kDa PM protein. This binding is competed with a peptide that contains the RGD motif, as well as with fibronectin, which also includes this sequence, suggesting that the 80 kDa PM protein has an integrin-like function whose natural ligands are p33 and p This is the first case where a PM ligand for a higher plant cell wall protein has been identified.

Microsporidia are obligate intracellular parasites, and a derivative of fungi, which harbor a rigid spore wall to resist adverse environmental pressures. The spore wall protein, which is thought to be the first and direct protein interacting with the host cell , may play a key role in the process of microsporidia infection.

The protein also has 6 heparin-binding motifs which are known to interact with extracellular glycosaminoglycans. Syntenic analysis indicated that gene loci of Nbhswp11 are conserved and syntenic between Nosema bombycis and Nosema ceranae.

Nbhswp11 was transcribed throughout the entire life stages, and gradually increased during days, in a silkworm that was infected by N. Western blotting analysis displayed NbHSWP11 expressed in the total mature spore proteins and spore coat proteins. Indirect immunofluorescence assay revealed NbHSWP11 located at the spore wall of mature spores and the spore coats. Furthermore, immune electron microscopy showed that NbHSWP11 localized in the cytoplasm of the sporont.

Within the developmental process of N. However, most of NbHSWP11 distributes on the membraneous structures of the sporoblast and mature spore. In addition, using a host cell binding assay, native protein NbHSWP11 in the supernatant of total soluble mature spore proteins is shown to bind to the host cell BmE surface. Finally, an antibody blocking assay showed that purified rabbit antibody of NbHSWP11 inhibits spore adherence and decreases the adherence rate of spores by Diffusion nearby elastic cell membranes.

The physical approach of a small particle to the cell membrane represents the crucial step before active internalization and is governed by Brownian diffusion. The pollen seasons show 3 main parts: Ambrosia artemisiifolia have a pronounced invasive character. Since , having been spread all over the country, it has become the most common weed in Romania.

There is an urgent need to organize interventions to stop ragweed expansion and to clear the areas already polluted. A new allergen from ragweed Ambrosia artemisiifolia with homology to art v 1 from mugwort. Art v 1, the major pollen allergen of the composite plant mugwort Artemisia vulgaris has been identified recently as a thionin-like protein with a bulky arabinogalactan-protein moiety.

A close relative of mugwort, ragweed Ambrosia artemisiifolia is an important allergen source in North America, and, since , ragweed has become a growing health concern in Europe as well. Weed pollen-sensitized patients demonstrated IgE reactivity to a ragweed pollen protein of apparently kDa. This reaction could be inhibited by the mugwort allergen Art v 1. The purified ragweed pollen protein consisted of a amino acid-long defensin-like domain with high homology to Art v 1 and a C-terminal proline-rich domain.

This part contained hydroxyproline-linked arabinogalactan chains with one galactose and 5 to 20 and more alpha-arabinofuranosyl residues with some beta-arabinoses in terminal positions as revealed by high field NMR.

The ragweed protein contained only small amounts of the single hydroxyproline-linked beta-arabinosyl residues, which form an important IgE binding determinant in Art v 1. Therefore, this protein from ragweed pollen constitutes a novel important ragweed allergen and has been designated Amb a 4. Weed pollen-sensitized patients demonstrated IgE reactivity to a ragweed pollen protein of apparently 29—31 kDa.

Ragweed Ambrosia artemisiifolia pollen allergenicity: Background Pollen of common ragweed Ambrosia artemisiifolia is a main cause of allergic diseases in Northern America. The weed has recently become spreading as a neophyte in Europe, while climate change may also affect the growth of the plant and additionally may also influence pollen allergenicity. To gain better insight in the molecular mechanisms in the development of ragweed pollen and its allergenic proteins under global change scenarios, we generated SuperSAGE libraries to identify di Paving the way for invasive species: Roads function as prime habitats and corridors for invasive plant species.

Yet despite the diversity of road types, there is little research on the influence of these types on the spread of invaders. Common ragweed Ambrosia artemisiifolia , a plant producing large amounts of allergenic pollen, was selected as a species model for examining the impact of road type on the spread of invasive plants.

We examined this relationship in an agricultural region of Quebec, Canada. We mapped plant distribution along different road types, and constructed a model of species presence.

Results support the hypothesis that attributes associated with paved roads strongly favour the spread of an opportunistic invasive plant species. Specifically, larger verges and greater disturbance associated with higher traffic volume create propitious conditions for common ragweed. To date, emphasis has been placed on controlling the plant in agricultural fields, even though roadsides are probably a much larger seed source. Strategies for controlling the weed along roads have only focused on major highways, even though the considerable populations along local roads also contribute to the production of pollen.

Management prioritizations developed to control common ragweed are thus questionable. Full Text Available Ragweed Ambrosia artemisiifolia is very allergeni plant species causing a big health problem to a sensitive person. Moreover, due its high cover values ragweed is also a problem in agricultural and non-agricultural areas. Floristic records , performed during August and beginning of September identified ragweed populations with significant number of units per area.

High cover values were recorded in sunflower and stubbles, and these places are considered a focus problem. High values were also registered in ruderal habitats, and along roads and canals. Field investigations confirmed the doubts that ragweed occupies and invades more and more areas.

Besides agronomic problem, ragweed is also a significant public health problem. Pollen of this weed species is exceptionally strong aeroallergen, causing big problems among sensitive persons during the summer time. Therefore, detailed aerobiological investigations — were performed using the volumetric method Burkard pollen and spore trap in order to identify parameters of pollination. Ragweed pollen was mostly present in the air at the end of summer.

This is the period when the allergic reaction among the sensitive persons is most registered. Pollination starts in July and finishes in October according to six year aerobiology monitoring. Length of pollination in the investigated area lasted on the average from 74 to 94 days, with the peak between 22th of August and 3rd of September. Total daily pollen counts varied from year to year from pollen grains per m3 of air to pollen grains per m3 of air.

Meteorological parameters have a significant influence for amount of pollen grains in the air. It is proved that concentration of the pollen in the air is getting higher along with higher temperature, but it the relative humidity increases concentration. Full Text Available In a previous paper we presented the localities in Romania where we identified populations of Ambrosia artemisiifolia.

Between , investigations were continuing. Our data clearly show that Ambrosia is present throughout the country. The territories heavily infested are railway embankments, along traffic routes, gravel pits, building sites, forest edges, industrial areas, cemeteries and recreational areas.

It is quite common to find ragweed in many private gardens, or flower pots in urban areas. The few foci observed along riversides got there by household waste and construction waste. In many rural communities find it on the drainage ditches.

Disturbed and neglected land on city limits and outside the city, abandonment of land without subsequent turning of stubble and another wrong agricultural practice, absence of ruderal weed control are the main causes that favor the dissemination of our country.

Intensity of anthropogenic influence is manifested mainly by transport of materials and soil movement during road rehabilitation and construction of highways. The recent observations show that could be expected to appear on agricultural fields, now being found only on the outskirts of cultivated land, at meters from high traffic roads. Ambrosia benefits from human activities to spread. This implies a strong control strategy.

The main objective of the fighting activities need to be to reduce damages caused by its pollen and to limit its expansion. If invasion by Ambrosia is left uncontrolled, increase of allergies could heavily augment the treatments. Knowledge about mechanical or chemical control of ragweed could be very important for road and rail services, agricultural institutions, farmers, staff responsible for managing natural areas, institutions that approves and oversees residential sites and factories, responsible personnel of the administrations from cities and rural localities.

Reducing the population is more required than. Full Text Available The aim of the present contribution was to determine the situation of Ambrosia artemisiifolia in Romania. This paper is a brief summary about the researches on the alien plant Ambrosia artemisiifolia in Romania.

At present, this alien plant is in the process of acclimatization and naturalization in our country. Nowadays the agricultural areas are greatly infested in Romania. However, the infestations on waste land or roadsides are rarely controlled. The annual pollen counts show an increasing tendency, indicating an increased local population. Ambrosia artemisiifolia has been studied by a high number of romanian scientists and many articles have been written on the topic.

For the study of the spreading of the Ambrosia artemisiifolia L. In the presence of the species was noticed in 49 locations.

In - , the observations continued and it was observed the emergence of the species in 28 new locations, also the expansion and amplification in the pryor locations.

The determinations were made in the months of June-September. In this work were listed a number of sites across Romania, where A. Currently the biggest problem is in the lowland and hill area of macro-regions 1, 3 and 4 where the species A. The paper presents personal observations on some morphological features, anatomical and ecological aspects. Full Text Available Herbicide resistant weed populations have developed due to the repeated application of herbicides. Elevated concentrations of atmospheric CO2 can have positive effects on weed growth, but how rising CO2 might affect herbicide resistant weeds is not known.

Ragweed Ambrosia artemisiifolia L. Plants were harvested following 8 weeks of CO2 exposure; at this time, they had begun to exhibit disease symptoms including spots on leaves and stems.

Elevated CO2 significantly increased top, root, and total plant biomass. Also, glyphosate resistant plants had significantly greater top, root, and total biomass than plants susceptible to the herbicide. There were no significant CO2 by ecotype interactions. Fungi from 13 genera were associated with ragweed , several of the which can be either pathogens i.

The common foliar disease powdery mildew was significantly higher on susceptible compared with resistant ragweed. Susceptible plants also showed an increased frequency of Rhizoctonia on leaves and Alternaria on stems; however, Fusarium occurred more frequently on resistant ragweed leaves.

Fungi were not affected by CO2 concentration or its interaction with ecotype. This study reports the first information on the effects of elevated CO2 on growth of herbicide resistant weeds.

This is also the first study examining the impact of herbicide resistance and elevated CO2 on fungi associated with weeds. What effects herbicide resistance might have on plant diseases and how rising atmospheric CO2 might impact these effects needs to be addressed, not only with important weeds but also with crops. Effects of elevated CO2 on biomass and fungi associated with two ecotypes of ragweed Ambrosia artemisiifolia L.

Herbicide resistant weed populations have developed due to the repeated application of herbicides. Fungi from 13 genera were associated with ragweed , several of which can be either pathogens i. Establishment and persistence of common ragweed Ambrosia artemisiifolia L. No data are available on whether rising carbon dioxide concentration [CO 2 ] or increased air temperature can alter the establishment and persistence of common ragweed Ambrosia artemisiifolia L.

To determine ragweed longevity, we exposed disturbed soil with a common seed bank population to an in situ temperature and [CO 2 ] gradient along an urban-rural transect beginning in early No other consistent differences in meteorological variables e. However, by the Fall of , and continuing through , urban ragweed populations had dwindled to a few plants.

The temporal decline in ragweed populations was not associated with increased disease, herbivory or auto-allelopathy, but was part of a demographic reduction in the total number of annual plant species observed for the urban location. A review of clinical efficacy, safety, new developments and adherence to allergen-specific immunotherapy in patients with allergic rhinitis caused by allergy to ragweed pollen Ambrosia artemisiifolia.

Allergic rhinitis is a common health problem in both children and adults. Allergen-specific immunotherapy AIT has disease-modifying effects and can induce immune tolerance to allergens. However, patient adherence to treatment with AIT seems to be quite low, mostly due to the fact that treatment with AIT is relatively time-demanding and, moreover, due to patients not receiving adequate information and education about the treatment before it starts.

AIT is undergoing innovations and improvements in clinical efficacy, safety and patient adherence, especially with new approaches using new adjuvants, recombinant or modified allergens, synthetic peptides, novel routes of administration epidermal or intralymphatic , and new protocols, which might make AIT more acceptable for a wider range of patients and novel indications.

Patient education and support eg, recall systems is one of the most important goals for AIT in the future, to further enhance treatment success. Combining cutting and herbicide application for Ambrosia artemisiifolia control. The effect on Ambrosia artemisiifolia common ragweed of combining cutting and herbicide application was studied in pot experiments in Germany and Denmark in Single plants of common ragweed were established in 2 L pots in glasshouses.

Two cutting treatments were conducted: Lontrel , in Denmark: Matrigon , mesotrione in Germany and Denmark: Callisto and glyphosate in Germa Predicting the potential distribution of invasive exotic species using GIS and information-theoretic approaches: A case of ragweed Ambrosia artemisiifolia L. Invasive exotic species pose a growing threat to the economy, public health, and ecological integrity of nations worldwide. Explaining and predicting the spatial distribution of invasive exotic species is of great importance to prevention and early warning efforts.

We are investigating the potential distribution of invasive exotic species, the environmental factors that influence these distributions, and the ability to predict them using statistical and information-theoretic approaches.

However, for most species, absence data are not available. Presented with the challenge of developing a model based on presence-only information, we developed an improved logistic regression approach using Information Theory and Frequency Statistics to produce a relative suitability map.

This paper generated a variety of distributions of ragweed Ambrosia artemisiifolia L. Our logistic regression model was based on Akaike's Information Criterion AIC from a suite of ecologically reasonable predictor variables.

Based on the results we provided a new Frequency Statistical method to compartmentalize habitat-suitability in the native range. Finally, we used the model and the compartmentalized criterion developed in native ranges to "project" a potential distribution onto the exotic ranges to build habitat-suitability maps.

Common ragweed Ambrosia artemisiifolia L. Ragweed pollen is the main cause of allergenic diseases in Northern America, and the weed has become a spreading neophyte in Europe. Climate change and air pollution are speculated to affect the allergenic potential of pollen.

The objective of this study was to investigate the effects of NO2 , a major air pollutant, under controlled conditions, on the allergenicity of ragweed pollen. Ragweed was exposed to different levels of NO2 throughout the entire growing season, and its pollen further analysed. Spectroscopic analysis showed increased outer cell wall polymers and decreased amounts of pectin.

Proteome studies using two-dimensional difference gel electrophoresis and liquid chromatography-tandem mass spectrometry indicated increased amounts of several Amb a 1 isoforms and of another allergen with great homology to enolase Hev b 9 from rubber tree. Analysis of protein S-nitrosylation identified nitrosylated proteins in pollen from both conditions, including Amb a 1 isoforms.

However, elevated NO2 significantly enhanced the overall nitrosylation. Finally, we demonstrated increased overall pollen allergenicity by immunoblotting using ragweed antisera, showing a significantly higher allergenicity for Amb a 1. The data highlight a direct influence of elevated NO2 on the increased allergenicity of ragweed pollen and a direct correlation with an increased risk for human health.

Expansion and aerobiology of Ambrosia artemisiifolia L. Full Text Available [b]Introduction and objective. The purpose of this study was to survey the spread and distribution of this species in Slovakia and to analyse its airborne pollen pattern. Aerobiological sampling was based on the analysis of pollen records at five aerobiological stations in Slovakia.

Highest airborne pollen counts were recorded in Nitra, Trnava and Bratislava Monitoring Stations situated in the areas most infested by A. Besides the most infested areas, high airborne pollen counts were also recorded in territories where the plant species was less abundant.

During the study period, the intensity of [i] Ambrosia. Full Text Available The effect on Ambrosia artemisiifolia common ragweed of combining cutting and herbicide application was studied in pot experiments in Germany and Denmark in Matrigon, mesotrione in Germany and Denmark: Callisto and glyphosate in Germany: Roundup Bio were applied at 4 doses at three different timings: The plants were harvested 5 weeks after the last herbicide application.

At both sites clopyralid and mesotrione had a low efficacy on common ragweed when applied on developed plants with only minor differences in efficacy at the three timings. Application after cutting improved the efficacy of clopyralid at both sites and of mesotrione in Denmark.

In Germany glyphosate had a higher efficacy on noncut plants in comparison to the cut plants, in Denmark it was vice versa. The highest dose of glyphosate provided higher control levels on developed plants than clopyralid and mesotrione at both sites. In Denmark the highest effects were obtained shortly after cutting with the maximum dose of each herbicide and declined with time between cutting and herbicide application. In summary the results demonstrated that herbicides can be applied shortly after cutting without loss of efficacy.

Agricultural fields under integrated pest management and ecological farming were monitored The aim was to assess the performance of chemical and other control measures against ragweed under farming conditions of the region. These parameters were ranked and, by way of multiplication, merged into one single value, which can be expressed as degree of a defined intense infestation level.

Such approach is considered to be useful to track recuperation efforts and estimate control efficiency by comparing pre and post measure infestation status. The index is applied to results of the growing season, which is illustrated by some examples. Molecular and immunological characterization of ragweed Ambrosia artemisiifolia L. Full Text Available Climate change and air pollution, including ozone is known to affect plants and might also influence the ragweed pollen, known to carry strong allergens.

We compared the transcriptome of ragweed pollen produced under ambient and elevated ozone by sequencing. Pollen surface was examined by scanning electron microscopy and attenuated total reflectance-Fourier transform infrared spectroscopy ATR-FTIR, and phenolics were analysed by high-performance liquid chromatography. Elevated ozone had no influence on the pollen size, shape, surface structure or amount of phenolics.

Transcriptomic analyses showed changes in expressed-sequence tags ESTs, including allergens. The data highlight a direct influence of ozone on the exine components and transcript level of allergens. As the total protein amount of Amb a 1 was not altered, a direct correlation to an increased risk to human health could not be derived.

Additional, the sequencing contributes to the identification of stress-related transcripts in mature pollen that could be grouped into distinct gene ontology terms. Climate change and air pollution, including ozone is known to affect plants and might also influence the ragweed pollen, known to carry strong allergens.

Pollen surface was examined by scanning electron microscopy and attenuated total reflectance-Fourier transform infrared spectroscopy ATR-FTIR , and phenolics were analysed by high-performance liquid chromatography. Transcriptomic analyses showed changes in expressed-sequence tags ESTs , including allergens. New Sesquiterpenoids from Ambrosia artemisiifolia L. Full Text Available A new pseudoguaianolide 1 and two new guaiane-type sesquiterpene glucosides 2 and 3, were isolated from the aerial parts of Ambrosia artemisiifolia L together with two known sesquiterpene dilactones 4 and 5.

The isolated compounds were evaluated for cytotoxicity against human promyelocytic leukemia HL cell lines in vitro, but were all inactive. Results showed that increasing density of A. There was no significant impact on peanut plant height. Exponential regression model was the best in describing the relationship between A.

Immunoproteomic characterization of Ambrosia artemisiifolia pollen allergens in canine atopic dermatitis. Short ragweed Ambrosia artemisiifolia pollen represents one of the major seasonal sources of allergenic pollen proteins in Europe, particularly in the Pannonian valley of the Balkan region. Therefore, characterization of Ambrosia artemisiifolia pollen components, in terms of defining major and minor allergens that induce clinically manifested allergic reaction in dogs, is important for valid diagnosis and efficient therapy.

This study has, for the first time, characterized and identified major Ambrosia artemisiifolia allergens in CAD, using an immunoproteomic approach. To assess the prevalence of specific IgE in electrophoretically separated ragweed pollen proteins, individual reactivity of sera from dogs with CAD was analyzed and compared to the reactivity of sera from healthy dogs in the non-reducing conditions, which were found optimal for specific canine IgE detection.

The most prominent ragweed proteins in CAD, represent, as in humans, variants of all five isoallergens of the Amb a 1 group pectate lyase: Air pollution is frequently proposed as a cause of the increased incidence of allergy in industrialised countries. New sets of genomic and expressed sequence tag EST based simple sequence repeats SSRs markers were developed in this species using three approaches. After validation, 13 genomic SSRs and 13 EST-SSRs were retained and used to characterize the genetic diversity and population genetic structure of Ambrosia artemisiifolia populations from the native North America and invasive Europe ranges of the species.

Analysing the mating system based on maternal families did not reveal any departure from complete allogamy and excess homozygosity was mostly due the presence of null alleles.

High genetic diversity and patterns of genetic structure in Europe suggest two main introduction events followed by secondary colonization events. Cross-species transferability of the newly developed markers to other invasive species of the Ambrosia genus was assessed. Cloning, expression, and characterization of pollen allergens from Humulus scandens Lour Merr and Ambrosia artemisiifolia L.

The allergen genes were selectively amplified in the weed pollen cDNA pool by using a special PCR profile, with the primers designed by a modeling procedure. Following truncated gene cloning and confirmation of the pollen source, unknown 3'cDNA ends were identified by using the 3'-RACE method.

The gene function conferred by the full-length coding region was evaluated by a homologue search in the GenBank database. Recombinant proteins expressed in Escherichia coli pET RosettaBlue cells were subsequently characterized by N-terminal end sequencing, IgE binding, and crossreactivity.

Three full-length cDNAs were obtained in each weed. Five recombinant proteins were abundantly expressed in nonfusion forms and were confirmed by using the N-terminal end sequence identity. Sera from patients who were allergic to A artemisiifolia reacted not only with rAmb a 8 D03 derived from A artemisiifolia , but also with recombinant protein rHum s 1 LCM9 derived from H scandens, which confirmed the allergenicity and cross-reactivity of the recombinant proteins from the 2 sources.

Comparison of the degenerate primers used for truncated gene cloning with the full-length cDNA demonstrated that alternative nucleotide degeneracy occurred. This study demonstrates a useful method for cloning homologous allergen genes across different species, particularly for little-studied species. The weeding of Ambrosia artemisiifolia and sanitary risks.

Ambrosia artemisiifolia is a potentially allergenic annual herbaceous plant coming from North America and widespread in Italy, where it can be easily seen since May-April. Its pollination is mainly windborne and each plant is able to produce billions of pollen grains. The pollen peaks are in the hottest days in the absence of rain and wind.

In susceptible individuals, the great amount of pollen produced by this species may cause rhinitis and severe asthma attacks. Some allergic subjects can manifest disorders already at a concentration of a few granules per cubic metre. Chemical control is often practiced on a large scale and uses herbicides.

A major risk is the result of the unprofessional use of chemicals by the population, especially in residential or very busy areas eg railways, urban areas. In this paper we propose preventive measures of chemical hazards that may be resulting from the excessive use of plant protection products. Its pollen can be transported over large distances and has been recognized as a significant cause of hayfever and asthma D'Amato et al.

RegCM4 was adapted to incorporate the pollen emissions from ORCHIDEE French Global Land Surface Model and a pollen tracer model for describing pollen convective transport, turbulent mixing, dry and wet deposition over extensive domains, using consistent assumption regarding the transport of multiple species Fabien et al.

We performed two families of recent-past simulations on the Euro-Cordex domain simulation for future condition is been considering. The observations were divided into two groups and used for calibration and validation separately. A wide range of possible calibration coefficients were tested for each calibration station, making the bias between observations and simulations within an admissible value then.

Gradual loss of genetic diversity of Ambrosia artemisiifolia L. Over the last two decades, while expanding toward southern parts of Serbia, this common ragweed has become a very troublesome plant species in the whole country.

Considering the importance of genetic studies in understanding of invasive species, our main objectives in this study were to analyze the genetic diversity and genetic structure of Ambrosia artemisiifolia populations from Central Serbia, a relatively recently invaded region. Comparing values of genetic measures obtained by microsatellite analyses, a number of differences were detected in genetic diversity between sampled populations.

Allelic richness-r ranged from 5. We observed greater genetic variability in populations from the northern part of investigated area than in southern populations. Data obtained for analyses of differentiation and gradual losses of genetic diversity of sampled populations provides useful information about invasion dynamics of common ragweed in recently invaded region. Changes in defense of an alien plant Ambrosia artemisiifolia before and after the invasion of a native specialist enemy Ophraella communa.

Full Text Available The evolution of increased competitive ability hypothesis EICA predicts that when alien plants are free from their natural enemies they evolve lower allocation to defense in order to achieve a higher growth rate.

If this hypothesis is true, the converse implication would be that the defense against herbivory could be restored if a natural enemy also becomes present in the introduced range. We tested this scenario in the case of Ambrosia artemisiifolia common ragweed - a species that invaded Japan from North America. We collected seeds from five North American populations, three populations in enemy free areas of Japan and four populations in Japan where the specialist herbivore Ophraella communa naturalized recently.

Using plants grown in a common garden in Japan, we compared performance of O. Conversely, in locations where the herbivore O. These results strengthen the case for EICA and suggest that defense levels of alien populations can be recuperated rapidly after the native specialist becomes present in the introduced range.

Our study implies that the plant defense is evolutionary labile depending on plant-herbivore interactions. Northern range edge equilibrium of Ambrosia artemisiifolia L. Full Text Available Description of the subject. The geographic distributions of a species, be it native or alien, is expected to be limited at some point by environmental conditions. In this situation, a range edge equilibrium REE takes place, i.

The occurrence of REE has never been tested for an invasive species. In Western Europe, the invasive weed Ambrosia artemisiifolia L. It is currently unknown whether the range has reached a limit or not. Information about how the species responds to sunflower competition is also lacking. This work addressed two questions: Has the northern part of A.

Plots were established in an agricultural field ca. The following year, the population growth rates and the soil seed bank were assessed. The species established populations with relatively high growth rates and soil seed bank. Sunflower competition did not have a significant impact on plant performance.

The results invalidate the hypothesis of equilibrium at the current margin of A. Let native species take their course: Ambrosia artemisiifolia replacement during natural or ;artificial; succession. In this study, we considered the time-span in which the species is suppressed during active restoration actions and passive spontaneous vegetation recovery. In particular, we envisaged that A. Three different treatments were applied within an abandoned quarry area commonly invaded by A.

We determined the effect of mixtures of grassland species, established from native hayseed or from a commercial seed mixture, on A. The results demonstrated that, after the first growing season, compared with spontaneous succession, both commercial seed and hayseed resulted in a strong reduction of A. After the second growing season, A. This study indicated that both active and passive vegetation recovery by niche filling and competitive exclusion could be used as methods individually or in combination with other methods, such as mowing and biological control, to suppress A.

Scientific Opinion on the effect on public or animal health or on the environment on the presence of seeds of Ambrosia spp. The genus Ambrosia Asteraceae family is distributed worldwide. Ambrosia artemisiifolia common ragweed has heavily colonised several areas of South-East Europe. Life history trait differentiation and local adaptation in invasive populations of Ambrosia artemisiifolia in China. Local adaptation has been suggested to play an important role in range expansion, particularly among invasive species.

However, the extent to which local adaptation affects the success of an invasive species and the factors that contribute to local adaptation are still unclear. This study aimed to investigate a case of population divergence that may have contributed to the local adaptation of invasive populations of Ambrosia artemisiifolia in China.

Common garden experiments in seven populations indicated clinal variations along latitudinal gradients, with plants from higher latitudes exhibiting earlier flowering and smaller sizes at flowering. In reciprocal transplant experiments, plants of a northern Beijing origin produced more seeds at their home site than plants of a southern Wuhan origin, and the Wuhan-origin plants had grown taller at flowering than the Beijing-origin plants in Wuhan, which is believed to facilitate pollen dispersal.

These results suggest that plants of Beijing origin may be locally adapted through female fitness and plants from Wuhan possibly locally adapted through male fitness. Selection and path analysis suggested that the phenological and growth traits of both populations have been influenced by natural selection and that flowering time has played an important role through its direct and indirect effects on the relative fitness of each individual.

This study evidences the life history trait differentiation and local adaptation during range expansion of invasive A. New insights into ragweed pollen allergens. Pollen allergens from short ragweed Ambrosia artemisiifolia cause severe respiratory allergies in North America and Europe. To date, ten short ragweed pollen allergens belonging to eight protein families, including the recently discovered novel major allergen Amb a 11, have been recorded in the International Union of Immunological Societies IUIS allergen database.

With evidence that other components may further contribute to short ragweed pollen allergenicity, a better understanding of the allergen repertoire is a requisite for the design of proper diagnostic tools and efficient immunotherapies.

This review provides an update on both known as well as novel candidate allergens from short ragweed pollen, identified through a comprehensive characterization of the ragweed pollen transcriptome and proteome. Common ragweed invasion in Sweden: Common ragweed Ambrosia artemisiifolia is a neophyte from North America that has spread rapidly throughout Europe. Because the pollen of common ragweed is highly allergic, many countries have adopted containment and mitigation measures.

The neophyte has only recently established flowering populations in Sweden. We use this well documented case to study the early impacts of an invasive species on human health.

Our identification strategy relies on spatial and temporal variation in common rag Full Text Available Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants.

Within this study, we investigated germination characteristics of Ambrosia artemisiifolia L. We determined germination rates and speed under different temperature conditions. From these parameters we calculated minimal, optimal, and maximal temperature for germination. We also investigated the frost tolerance of seedlings.

The European populations were characterized by a higher fitness with higher germination rates and germination speed, increased biomass and higher frost tolerance of seedlings. Furthermore, the temperature niche width for germination was significantly broader for the European populations.

The increased frost tolerance of the European populations might allow germination earlier in the year which may subsequently lead to higher biomass allocation — due to a longer growing period — and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and sharpen the existing problems.

Effects of seed traits variation on seedling performance of the invasive weed, Ambrosia artemisiifolia L. Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits.

However, very few studies have investigated seed traits variations and their consequences on seedling performance. Specifically, the following questions have been addressed by this work: With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments.

During seedling growth, performance-related traits were measured. A high variability in seed traits was highlighted.

Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance.

Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits. Prevalence of sensitization to weed pollens of Humulus scandens,Artemisia vulgaris, and Ambrosia artemisiifolia in northern China. Weed pollens are common sources of allergens worldwide.

The prevalence of weed pollen sensitization is not yet fully known in China. The purpose of this study was to investigate the prevalence of sensitization to weed allergens from Artemisia, Ambrosia ,and Humulus in northern China. A total of subjects aged from 5 to 68 years visiting our clinic from June to October underwent intradermal testing using a panel of 25 allergen sources. Subjects with positive skin responses to any pollen were further tested for their serum concentrations of IgE antibodies against Artemisia vulgaris, Ambrosia artemisiifolia ,and Humulus scandens,and against the purified allergens,Art v 1 and Amb a 1.

Of 1 subjects, had positive intradermal reactions to pollen and donated serum for IgE testing. The prevalence of positive intradermal responses to pollens of Artemisia sieversiana,Artemisia annua,A.

Among the intradermal positive subjects,the prevalence of specific IgE antigens to A. The prevalence of specific IgE antigens to the allergen Art v 1 was The correlation between the presence of IgE antibodies specific to A. There were no correlations between the presence of IgE antibodies to H. The intradermal prevalence of weed pollen sensitization among allergic subjects in northern China is about Correlations of specific IgE antibodies suggest that pollen allergens from Artemisia and Humulus are independent sources for primary sensitization.

Mesoscale atmospheric transport of ragweed pollen allergens from infected to uninfected areas. Allergenic ragweed Ambrosia spp. However, the action of air temperature, humidity and solar radiation on pollen grains in the atmosphere could impact on the ability of long distance transported LDT pollen to maintain allergenic potency. Here, we report that the major allergen of Ambrosia artemisiifolia pollen Amb a 1 collected in ambient air during episodes of LDT still have immunoreactive properties.

The amount of Amb a 1 found in LDT ragweed pollen grains was not constant and varied between episodes. In addition to allergens in pollen sized particles, we detected reactive Amb a 1 in subpollen sized respirable particles.

These findings suggest that ragweed pollen grains have the potential to cause allergic reactions, not only in the heavily infested areas but, due to LDT episodes, also in the regions unaffected by ragweed populations. Glyphosate resistance in common ragweed Ambrosia artemisiifolia L.

Glyphosate is one of the most commonly used broad-spectrum herbicides over the last 40 years. Due to widespread adoption of glyphosate-resistant GR crop technology, especially, corn, cotton, and soybean, several weed species in agronomic situations have developed resistance to this herbicide. Glyphosate resistance in giant ragweed Ambrosia trifida L.

A giant ragweed population from a glyphosate-resistant GR soybean field in Mississippi was suspected to be resistant to glyphosate.

Greenhouse and laboratory studies were conducted to confirm and quantify the magnitude of glyphosate resistance in the giant ragweed population and to elucidate the p Full Text Available Only a limited spectrum of active substances is available for weed control in leguminous plants and sunflowers.

Since the official plant protection service in Brandenburg conducts herbicide field trials in these crop species in the region around Drebkau for the investigation of practicable approaches for control of Ambrosia artemisiifolia.

For the cultivation of lupins only pre-emergence herbicides are registered. Due to the high density of A. Likewise, the performance of authorised herbicides in sunflowers is insufficient. In the region concerned cultivation of grain legumes and sunflowers is limited in areas with high coverage rate of A. Full Text Available Since the beginning of common ragweed registration in North Rhine-Westphalia in there have been ragweed records, among them 31 populations with more than individuals.

Common ragweed is not yet established in North Rhine-Westphalia but seems to do very well on sandy soils in the Lowland. North Rhine-Westphalia is tackling common ragweed in an early stage of invasion and will continue the strategy of rapid response to achieve a total eradication. Thirty-three countries have already signed the Memorandum of Understanding and over researchers with specialists in weed research, invasive alien species management, ecology, aerobiology, allergology and economics are registered participants of SMARTER.

COST Actions interlink nationally funded research projects and enable and finance conferences, working groups, training schools and research exchanges. SMARTER aims to initiate and develop long-term and sustainable control methods, to integrate these into existing mechanical and chemical control measures, and to quantify the success of these measures both for agriculture and health. The focus is on biological control methods with insects and fungi especially using alien species from the area of origin of Ambrosia and vegetation management to achieve a competitive plant cover.

For this, we develop and parameterize models, starting from the population dynamics of Ambrosia , on the impact of control measures on the frequency and distribution of Ambrosia and finally on pollen counts and allergy occurrences, each with both ecological and economic components. The necessary data are derived from the many experiments that we carry out in well-coordinated studies across Europe. SMARTER will allow the various stakeholders to select optimal habitat- and region-specific combinations of control methods.

After an introduction and overview of the structure and the state of the Action, we briefly describe two planned activities typical for our Action, a study on the population dynamics of Ambrosia in different climates and habitats in Europe as a basis for estimating the efficiency of control measures, and an interdisciplinary study to clarify the impact the of North American native Ambrosia leaf beetle Ophraella communa Coleoptera.

Climate-change-induced range shifts of three allergenic ragweeds Ambrosia L. Full Text Available Invasive allergenic plant species may have severe health-related impacts.

In this study we aim to predict the effects of climate change on the distribution of three allergenic ragweed species Ambrosia spp. We estimate that by year , the distribution range of all three ragweed species increases towards Northern and Eastern Europe under all climate scenarios.

We conclude that areas in Europe affected by severe ragweed associated allergy problems are likely to increase substantially by year , affecting millions of people. To avoid this, management strategies must be developed that restrict ragweed dispersal and establishment of new populations. Precautionary efforts should limit the spread of ragweed seeds and reduce existing populations. Only by applying cross-countries management plans can managers mitigate future health risks and economical consequences of a ragweed expansion in Europe.

Invasive allergenic plant species may have severe health-related impacts. We quantify the extent of the increase in 'high allergy risk' HAR areas, i.

Effects of climate change and seed dispersal on airborne ragweed pollen loads in Europe. Common ragweed Ambrosia artemisiifolia is an invasive alien species in Europe producing pollen that causes severe allergic disease in susceptible individuals. Ragweed plants could further invade European land with climate and land-use changes.

However, airborne pollen evolution depends not only on plant invasion, but also on pollen production, release and atmospheric dispersion changes. To predict the effect of climate and land-use changes on airborne pollen concentrations, we used two comprehensive modelling frameworks accounting for all these factors under high-end and moderate climate and land-use change scenarios. We estimate that by airborne ragweed pollen concentrations will be about 4 times higher than they are now, with a range of uncertainty from 2 to 12 largely depending on the seed dispersal rate assumptions.

About a third of the airborne pollen increase is due to on-going seed dispersal, irrespective of climate change. The remaining two-thirds are related to climate and land-use changes that will extend ragweed habitat suitability in northern and eastern Europe and increase pollen production in established ragweed areas owing to increasing CO2. Therefore, climate change and ragweed seed dispersal in current and future suitable areas will increase airborne pollen concentrations, which may consequently heighten the incidence and prevalence of ragweed allergy.

Full Text Available Since the common ragweed , Ambrosia artemisiifolia , which was introduced from North America has also been found in Bavaria in larger stocks and has an increasing tendency to spread.

After receiving the report of the Bavarian Ministry of Health, the Bavarian Parliament addressed the implications for health. There was consensus across all political groups to combat the plant. The 96 district administration authorities, which each have a trained ragweed officer, report to the registration office on new verified ragweed locations with more than plants.

The reports of common ragweed stands are filed by citizens or through research by the district administration authorities, who are also responsible for supporting the fight against stocks. On behalf of the Bavarian Ministry of Health, the Working Group Biodiversity monitors the situation and finds many new locations. Since , new common ragweed stocks were registered. After control measures there are currently known remaining stocks.

Since , however, the populated area has tripled. This means that the control measures need further improvement. This is especially true for the common ragweed stocks along roadsides where the plants have increased massively in recent years. Sustainable control has proved to be particularly difficult. Ragweed -induced allergic rhinoconjunctivitis: Ragweed -induced allergic rhinoconjunctivitis has long been seen as a major immunologic condition in Northern America with high exposure and sensitization rates in the general population.

The invasive occurrence of ragweed A. Possible explanations for its worldwide spread are climate change and urbanization, as well as pollen transport over long distances by globalized traffic and winds.

Due to the increasing disease burden worldwide, and to the lack of a current and comprehensive overview, this study aims to review the current and emerging treatment options for ragweed -induced rhinoconjunctivitis. Sound clinical evidence is present for the symptomatic treatment of ragweed -induced allergic rhinoconjunctivitis with oral third-generation H1-antihistamines and leukotriene antagonists.

The topical application of glucocorticoids has also been efficient in randomized controlled clinical trials. Combined approaches employing multiple agents are common. The mainstay of causal treatment to date, especially in Northern America, is subcutaneous immunotherapy with the focus on the major allergen, Amb a 1.

Beyond this, growing evidence from several geographical regions documents the benefit of sublingual immunotherapy. Future treatment options promise more specific symptomatic treatment and fewer side effects during causal therapy. Novel antihistamines for symptomatic treatment are aimed at the histamine H3-receptor. New adjuvants with toll-like receptor 4 activity or the application of the monoclonal anti-immunoglobulin E antibody, omalizumab, are supposed to enhance conventional immunotherapy.

An approach targeting toll-like receptor 9 by. Full Text Available The European Union handed over the regulation of common ragweed Ambrosia artemisiifolia to the member states. Austrian administration started to ask for control measures, i. Any sustainable control measure must focus on the reduction of seeds produced by the annual ragweed. Seed bank dimension of ragweed turned out to be a good evaluation tool for any control measure.

To evaluate the importance of different spreading mechanisms of dispersal, a need for serious figures can be stated. Based on our seed trap experiments and comparable slip stream experiments by German botanists, the efficiency of vehicles in spreading ragweed over long distances was low. However, machines used by road services cutter, moulder turned out to spread thousands of seeds. Besides, there is serious indication that trucking agricultural food and seeds over long distances is relevant for ragweed seed dispersal.

Dispersal of thousands of ragweed seeds from contaminated agricultural fields to fields not yet infested is caused by harvesters and other agricultural machines. Regulations to reduce the ragweed load in traded agricultural goods are to be implemented in future.

Small populations of ragweed should be simply uprooted and composted as long as they bear no flowers. Various possibilities are known for control of common ragweed in agricultural fields with mechanical and chemical methods. Limits are set in sunflowers because sunflower and ragweed are botanically related. The legal obligation of reporting and control — introduced in Switzerland a couple of years ago — allowed the development of specific distribution maps and enhanced the quality of control measures.

Facts and figures from the Canton of Geneva prove that the ragweed invasion has been stopped, but the species is not eradicated. The results of Geneva represent the results of good ragweed control in the whole country. Beside agriculture, traffic infrastructure, building sites, gravel pits and urban park and garden areas are sensible to ragweed invasion. The responsibility of individuals helps to improve control efficiency even if financial funds are small.

A sustainable control success depends on the efficiency to hamper seed production. The reduction of pollen quantity in the air in a long term is part of the earnings for the control effort.

Goddess

Competitive inhibition by several structurally related peptides and proteins noted the specific requirement for the RGD sequence.

Thus, the RGD-binding activity of Arabidopsis fulfils the adhesion features of integrins, i. Cell wall accumulation of fluorescent proteins derived from a trans-Golgi cisternal membrane marker and paramural bodies in interdigitated Arabidopsis leaf epidermal cells. In most dicotyledonous plants, leaf epidermal pavement cells develop jigsaw puzzle-like shapes during cell expansion. Therefore, visualization of membrane trafficking in leaf pavement cells should contribute an understanding of the mechanism of plant cell morphogenesis.

To reveal membrane trafficking in pavement cells , we observed monomeric red fluorescent protein-tagged rat sialyl transferases, which are markers of trans-Golgi cisternal membranes , in the leaf epidermis of Arabidopsis thaliana. Quantitative fluorescence imaging techniques and immunoelectron microscopic observations revealed that accumulation of the red fluorescent protein occurred mostly in the curved regions of pavement cell borders and guard cell ends during leaf expansion.

Transmission electron microscopy observations revealed that apoplastic vesicular membrane structures called paramural bodies were more frequent beneath the curved cell wall regions of interdigitated pavement cells and guard cell ends in young leaf epidermis. In addition, pharmacological studies showed that perturbations in membrane trafficking resulted in simple cell shapes. These results suggested possible heterogeneity of the curved regions of plasma membranes , implying a relationship with pavement cell morphogenesis.

An enzyme complex responsible for the TUA chain biosynthesis was purified and characterized. TUAS displays hydrophobic properties and is found primarily associated with the cytoplasmic membrane. The purified TUAS contains carotinoids and lipids. TUAS activity is diminished by phospholipase digestion.

We propose that TUAS serves as a multitasking polysaccharide assembling station on the bacterial membrane. Actin filaments regulate the adhesion between the plasma membrane and the cell wall of tobacco guard cells. During the opening and closing of stomata, guard cells undergo rapid and reversible changes in their volume and shape, which affects the adhesion of the plasma membrane PM to the cell wall CW.

The dynamics of actin filaments in guard cells are involved in stomatal movement by regulating structural changes and intracellular signaling. However, it is unclear whether actin dynamics regulate the adhesion of the PM to the CW. In this study, we investigated the relationship between actin dynamics and PM-CW adhesion by the hyperosmotic-induced plasmolysis of tobacco guard cells.

We found that actin filaments in guard cells were depolymerized during mannitol-induced plasmolysis. However, treatment with latrunculin B alleviated the RGDS peptide-induced plasmolysis and endocytosis.

Our results reveal that the actin depolymerization is involved in the regulation of the PW-CW adhesion during hyperosmotic-induced plasmolysis in tobacco guard cells. In this study, a series of nanocomposite membranes were fabricated with the PVA-influenced functionalized MWCNTs reinforced into the Nafion polymer matrix by a solution casting method.

After that, the nanocomposite membranes were characterized by thermo-gravimetric analysis TGA to observe the thermal enhancement caused by effective cross-linking between the f-MWCNTs with the composite polymer matrixes. Diffusion of nitric oxide across cell membranes of the vascular wall requires specific connexin-based channels.

NO is generated within cells and frequently must be transferred to responsive neighboring cells , as occurs in the endothelium-dependent relaxation of smooth muscle cells observed in blood vessels. It is thought that NO diffuses freely across cell membranes , but it may also permeate through low resistant membrane pathways.

Here, we describe the participation of connexin Cx -formed channels in the NO transport across cell membranes and between endothelial and smooth muscle cells. We used a water-soluble NO donor of high molecular weight S-nitrosylated albumin, BSA-NO that does not permeate through cell membranes or Cx-based channels and the NO-sensitive dye 4,5-diaminofluorescein diacetate to detect changes of intracellular NO concentration.

We found that NO generated in the extracellular space was not detected intracellularly in Cx-deficient HeLa cells , suggesting that cell membrane represents a significant diffusion barrier for NO transfer.

In contrast, NO closed hemichannels of HeLa-Cx32 cells , which otherwise are permeable to NO if are opened by a divalent cation-free extracellular solution. Consistent with this, blockade of Cx-based channels abolished the myoendothelial NO transfer and associated NO-dependent vasodilation induced by acethylcholine.

These results indicate that Cx-based channels play a key role in the NO-dependent tonic control of vascular function and may direct the NO signal to specific targets, which provides a novel mechanistic basis for the critical role of Cxs in cell-cell communication in the vessel wall. Perturbation of the Staphylococcus aureus cytoplasmic membrane CM is felt to play a key role in the microbicidal mechanism of many antimicrobial peptides APs.

We hypothesized that the relationships between MP and killing may differ for distinct APs. Four APs with different structure-activity relationships were examined: MP was quantified fluorometrically by calcein release. All APs tested, except polymyxin B, caused concentration-dependent MP and killing of whole cells , but not of protoplasts. The reduced AP susceptibility of protoplasts was associated with increased cardiolipin and lysyl-phosphatidylglycerol content and reduced fluidity of their CMs.

Collectively, these results indicate that i structurally distinct APs likely exert their staphylocidal effects by differing mechanisms, ii MP is not the sole event leading to AP-induced staphylocidal activity, iii a complex interrelationship exists between the CM and CW in AP-induced killing, and iv liposomes modeled upon whole cell or protoplast CMs can recapitulate the respective susceptibilities to killing by distinct APs. Peptidoglycan is the major component of the cell envelope of virtually all bacteria.

It has structural roles and acts as a selective sieve for molecules from the outer environment. Peptidoglycan synthesis is therefore one of the most important biogenesis pathways in bacteria and has been studied extensively over the last twenty years. The pathway starts in the cytoplasm, continues in the cytoplasmic membrane and finishes in the periplasmic space, where the precursor is polymerized into the peptidoglycan layer.

A number of proteins involved in this pathway, such as the Mur enzymes and the penicillin binding proteins PBPs , have been studied and regarded as good targets for antibiotics.

The present review focuses on the membrane steps of peptidoglycan synthesis that involve two enzymes, MraY and MurG, the inhibitors of these enzymes and the inhibition mechanisms.

We also discuss the challenges of targeting these two cytoplasmic membrane associated proteins in bacterial cells and the perspectives on how to overcome the issues. Knockout of the alanine racemase gene in Aeromonas hydrophila HBNUAh01 results in cell wall damage and enhanced membrane permeability. This study focused on the alanine racemase gene alr-2 , which is involved in the synthesis of d-alanine that forms the backbone of the cell wall. When the mutant was supplemented with d-alanine, growth was unaffected; deprivation of d-alanine caused the growth arrest of the starved mutant cells , but not cell lysis.

No alanine racemase activity was detected in the culture of the mutant. Additionally, a membrane permeability assay showed increasing damage to the cell wall during d-alanine starvation. No such damage was observed in the wild type during culture. Scanning and transmission electron microscopy analyses revealed deficiencies of the cell envelope and perforation of the cell wall.

Leakage of UV-absorbing substances from the mutants was also observed. Thus, the partial viability of the mutants and their independence of d-alanine for growth indicated that inactivation of alr-2 does not impose an auxotrophic requirement for d-alanine.

Effect of chirality and length on the penetrability of single- walled carbon nanotubes into lipid bilayer cell membranes. The ability of carbon nanotubes to enter the cell membrane acting as drug-delivery vehicles has yielded a plethora of experimental investigations, mostly with inconclusive results because of the wide spectra of carbon nanotube structures.

Because of the virtual impossibility of synthesizing CNTs with distinct chirality, we report a parametric study on the use of molecular dynamics to provide better insight into the effect of the carbon nanotube chirality and the aspect ratio on the interaction with a lipid bilayer membrane.

The simulation results indicated that a single- walled carbon nanotube utilizes different time-evolving mechanisms to facilitate their internalization within the membrane. These mechanisms comprise both penetration and endocytosis. It was observed that carbon nanotubes with higher aspect ratios penetrate the membrane faster whereas shorter nanotubes undergo significant rotation during the final stages of endocytosis. Furthermore, nanotubes with lower chiral indices developed significant adhesion with the membrane.

This adhesion is hypothesized to consume some of the carbon nanotube energy, thus resulting in longer times for the nanotube to translocate through the membrane. Combined effect of synthetic enterocin CRL35 with cell wall , membrane -acting antibiotics and muranolytic enzymes against Listeria cells. To evaluate the inhibition effectiveness of enterocin CRL35 in combination with cell wall , membrane -acting antibiotics and muranolytic enzymes against the foodborne pathogen Listeria.

Synthetic enterocin CRL35 alone and in combination with monensin, bacitracin, gramicidin, mutanolysin and lysozyme were used in this study. Antibiotics showed positive interactions with the bacteriocin in both strains tested.

On the other hand, when mutanolysin and enterocin CRL35 were added to resting cells in a buffer system, the lytic effect of mutanolysin was enhanced. However, the addition of mutanolysin showed no effect on the growth of L. Moreover, mutanolysin allowed the overgrowth of L.

Based on our results, we conclude that the combination of synthetic enterocin CRL35 with some antibiotics is effective against L. The effectiveness of the combination of synthetic enterocin CRL35 with muramidases seems to depend on complex environments, and more detailed studies need to be performed to elucidate this issue. Enterocin CRL35 represents a promising agent that not only can ensure the quality and safety of food but it can also be combined with several antimicrobial agents important in the medical field.

Deciphering the Metabolism of Undecaprenyl-Phosphate: During the biogenesis of bacterial cell-wall polysaccharides, such as peptidoglycan, cytoplasmic synthesized precursors should be trafficked across the plasma membrane. This essential process requires a dedicated lipid, undecaprenyl-phosphate that is used as a glycan lipid carrier.

The sugar is linked to the lipid carrier at the inner face of the membrane and is translocated toward the periplasm, where the glycan moiety is transferred to the growing polymer.

Undecaprenyl-phosphate originates from the dephosphorylation of its precursor undecaprenyl-diphosphate, with itself generated by de novo synthesis or by recycling after the final glycan transfer. Undecaprenyl-diphosphate is de novo synthesized by the cytosolic cis-prenyltransferase undecaprenyl-diphosphate synthase, which has been structurally and mechanistically characterized in great detail highlighting the condensation process.

In contrast, the next step toward the formation of the lipid carrier, the dephosphorylation step, which has been overlooked for many years, has only started revealing surprising features.

In contrast to the previous step, two unrelated families of integral membrane proteins exhibit undecaprenyl-diphosphate phosphatase activity: BacA and members of the phosphatidic acid phosphatase type 2 super-family, raising the question of the significance of this multiplicity. Moreover, these enzymes establish an unexpected link between the synthesis of bacterial cell-wall polymers and other biological processes. In the present review, the current knowledge in the field of the bacterial lipid carrier, its mechanism of action, biogenesis, recycling, regulation, and future perspective works are presented.

Plants are able to generate large leaf surfaces that act as two-dimensional solar panels with a minimum investment in building material, thanks to a hydrostatic skeleton. This requires high intracellular pressures up to 1 MPa , which depend on the presence of strong cell walls.

The walls of growing cells also called primary walls , are remarkably able to reconcile extreme tensile strength up to MPa with the extensibility necessary for growth.

All walled organisms are confronted with this dilemma - the need to balance strength and extensibility - and bacteria, fungi and plants have evolved independent solutions to cope.

In this Primer, we discuss how plant cells have solved this problem, allowing them to support often very large increases in volume and to develop a broad variety of shapes Figure 1A,B,D.

This shape variation reflects the targeted deposition of wall material combined with local variations in cell-wall extensibility, processes that remain incompletely understood.

Once the cell has reached its final size, it can lay down secondary wall layers, the composition and architecture of which are optimized to exert specific functions in different cell types Figure 1E-G.

Specialized secondary walls , such as those constituting seed mucilage, are stored in a dehydrated form in seedcoat epidermis cells and show rapid swelling upon hydration of the seed. Other walls , in particular in reserve tissues, can accommodate large amounts of storage polysaccharides, which can be easily mobilized as a carbon source. Physiological and transcriptional responses of Saccharomyces cerevisiae to d-limonene show changes to the cell wall but not to the plasma membrane.

Monoterpenes can, upon hydrogenation, be used as light-fraction components of sustainable aviation fuels. Fermentative production of monoterpenes in engineered microorganisms, such as Saccharomyces cerevisiae, has gained attention as a potential route to deliver these next-generation fuels from renewable biomass.

However, end product toxicity presents a formidable problem for microbial synthesis. Due to their hydrophobicity, monoterpene inhibition has long been attributed to membrane interference, but the molecular mechanism remains largely unsolved.

We found no alterations in membrane fluidity, structural membrane integrity, or fatty acid composition after the solvent challenge. A 4-fold increase in the mean fluorescence intensity per cell using calcofluor white stain and increased sensitivity to cell wall -degrading enzymes demonstrated that limonene disrupts cell wall properties.

Global transcript measurements confirmed the membrane integrity observations by showing no upregulation of ergosterol or fatty acid biosynthesis pathways, which are commonly overexpressed in yeast to reinforce membrane rigidity during ethanol exposure. This is the first report demonstrating that cell wall , rather than plasma membrane , deterioration is the main source of monoterpene inhibition.

We show that limonene can alter the structure and function of the cell wall , which has a clear effect on cytokinesis. Proteins in the cell wall and membrane of Cryptococcus neoformans stimulate lymphocytes from both adults and fetal cord blood to proliferate. Cryptococcus neoformans is an encapsulated yeast that infects patients who have defective cell -mediated immunity, including AIDS, but rarely infects individuals who have intact cell -mediated immunity.

Studies of the immune response to C. The goal of this study was to separate C. The lymphocyte response to fungal culture medium, whole organisms, disrupted organisms, and the yeast intracellular fraction or cell wall and membrane was studied by determining thymidine incorporation and by determining the number of lymphocytes at various times after stimulation. The cell wall and membrane of C. The optimal response occurred on day 7 of incubation, with 4 x 10 5 peripheral blood mononuclear cells per well and with 13 microg of cryptococcal protein per ml.

The number of lymphocytes increased with time in culture, indicating that thymidine incorporation was accompanied by proliferation. Proteinase K treatment of the cell wall and membrane abrogated lymphocyte proliferation, indicating that the molecule was a protein.

At least 18 discrete bands were resolved from the cell wall and membrane. Since a large percentage of healthy adults responded to the cryptococcal cell wall and membrane , a mitogenic effect was investigated by testing proliferation of fetal cord blood. An investigation into plasmolysis in the oomycete Achlya bisexualis reveals that membrane-wall attachment points are sensitive to peptides containing the sequence RGD and that cell wall deposition can occur despite retraction of the protoplast.

The structure and function of membrane-wall attachment sites in walled cells , and how these relate to animal focal adhesions, is an area that is poorly understood. In view of this, we investigated how membrane-wall attachments that form upon plasmolysis, respond to peptides that disrupt animal focal adhesions. The degree of cytoplasmic disruption during plasmolysis was also investigated. Upon hyperosmotic challenge, the protoplast in hyphae of the oomycete Achlya bisexualis typically retracted incompletely due to membrane-wall attachments.

The inclusion, in the plasmolysing solution, of peptides containing the sequence RGD disrupted these attachments in a dose-dependent manner. In some hyphae, protoplast retraction stopped temporarily at attachment points - upon resumption of retraction, material was left that traced the outline of the static protoplast. Staining of this material with fluorescence brightener indicated the presence of cellulose, which suggests that wall deposition was able to occur despite plasmolysis.

The F-actin cytoskeleton was disrupted during plasmolysis; peripheral F-actin staining was observed, but there was no distinct F-actin cap; staining was more diffuse; and there were fewer plaques compared with nonplasmolysed hyphae. Our data indicate that membrane-wall attachment points are sensitive to RGD-containing peptides and that wall deposition continues despite protoplast retraction and F-actin disruption.

Genome-wide reprogramming of regulatory networks, transport, cell wall and membrane biogenesis during arbuscular mycorrhizal symbiosis in Lotus japonicus. As a consequence of the fungal colonization and of the deep reorganization shown by arbusculated cells , important impacts on root transcriptome are expected. Induction of a subset 24 genes of these was tested and confirmed by qRT-PCR, and transcript location in arbusculated cells was demonstrated for seven genes using laser-dissected cells.

Improving the electro-transformation efficiency of Corynebacterium glutamicum by weakening its cell wall and increasing the cytoplasmic membrane fluidity. To improve the transformation efficiency of Corynebacterium glutamicum cells with heterogenous plasmid DNA and single-strand DNA ssDNA using a methodology based on electro-transformation.

A semicomplex hypertonic medium was selected with addition of glycine and DL-threonine to weaken cell walls and addition of Tween 80 and isonicotinic acid hydrazide to increase cytoplasmic membrane fluidity. Their contents were optimized by response surface methodology. Cell growth, electro-transformation buffer, and transformation protocol were also optimized.

Temporary heating inactivation of the host restriction enzyme showed a significant effect. Finally, a high transformation efficiency of 3. The results shed light on the application in functional genomics and genome editing of C. The rice dynamin-related protein DRP2B mediates membrane trafficking, and thereby plays a critical role in secondary cell wall cellulose biosynthesis.

Membrane trafficking between the plasma membrane PM and intracellular compartments is an important process that regulates the deposition and metabolism of cell wall polysaccharides. Dynamin-related proteins DRPs , which function in membrane tubulation and vesiculation are closely associated with cell wall biogenesis.

However, the molecular mechanisms by which DRPs participate in cell wall formation are poorly understood. Consistent with the expression of BC3 in mechanical tissues, the bc3 mutation reduces mechanical strength, which results from decreased cellulose content and altered secondary wall structure. Subcellular localization of fluorescence-tagged OsDRP2B and several compartment markers in protoplast cells showed that this protein not only lies at the PM and the clathrin-mediated vesicles, but also is targeted to the trans-Golgi network TGN.

An FM uptake assay in transgenic plants that express green fluorescent protein-tagged OsDRP2B verified its involvement in an endocytic pathway. All of these findings lead us to conclude that OsDRP2B participates in the endocytic pathway, probably as well as in post-Golgi membrane trafficking.

Mutation of OsDRP2B disturbs the membrane trafficking that is essential for normal cellulose biosynthesis of the secondary cell wall , thereby leading to inferior mechanical properties in rice plants. Enzymatic biofuel cells EBFCs utilize enzymes to convert chemical energy present in renewable biofuels into electrical energy and have shown much promise in the continuous powering of implantable devices. Currently, however, EBFCs are greatly limited in terms of power and operational stability with a majority of reported improvements requiring the inclusion of potentially toxic and unstable electron transfer mediators or multicompartment systems separated by a semipermeable membrane resulting in complicated setups.

Glucose oxidase and bilirubin oxidase were physically adsorbed onto these electrodes to form anodes and cathodes, respectively, and the EBFC produced power densities up to 0. Further, the electrodes were rejuvenated by a simple wash and reloading procedure. We postulate these porous and ultrahigh surface area electrodes will be useful for biosensing applications, and will allow reuse of EBFCs.

In this study the elastic spring constant of the yeast cell wall is probed with the atomic force microscope AFM under variable conditions. Cells were sequentially analyzed in rich growth medium YPD , a 0. Cells in late log phase, which have variable diameters within three to five microns, were immobilized on a patterned silicon substrate with holes approximately 3. Force curves were taken moving laterally across the cell in one dimension after exposure to each medium.

Spring constants of the cells , calculated from force curves, displayed a positional dependency and marked differences in high osmolarity medium and after the injection of sodium azide. This study demonstrates the ability of the AFM to investigate changes in cell morphology and correlate those findings to underlying physiological processes. The Lamportian cell wall. The Lamportian Warp-Weft hypothesis suggests a cellulose-extensin interpenetrating network where extensin mechanically couples the load-bearing cellulose microfibrils in a wall matrix that is best described as a microcomposite.

This model is based on data gathered from the extensin-rich walls of tomato and sycamore cell suspension culture, wherein extensin precursors are insolubilized into the wall by undefined crosslinks.

The authors recent work with cell walls isolated from intact tissue as well as walls from suspension cultured cells of the graminaceous monocots maize and rice, the non-graminaceous monocot asparagus, the primitive herbaceous dicot sugar beet, and the gymnosperm Douglas Fir indicate that although extensins are ubiquitous to all plant species examined, they are not the major structural protein component of most walls examined.

Clearly, structural wall protein alternatives to extensin exist and any cell wall model must take that into account. If we assume that extracellular matrices are a priori network structures, then new Hypless' structural proteins in the maize cell wall raise questions about the sort of network these proteins create: An electrochemical impedance spectroscopy study of polymer electrolyte membrane fuel cells electrocatalyst single wall carbon nanohorns-supported.

Additionally, as-prepared and oxidized SWNH Pt-supports were compared with conventional carbon black. Two different oxidizing treatments were considered: Both oxidizing treatments increased SWNH surface area; oxygen treatment increased surface area 4 times while acid treatment increased 2. The increase in surface area should be related to the opening access to the inner tube of SWNH. On the other hand, the oxygen treated SWNH sample allowed to obtain the highest electrocatalyst load.

Moreover, EIS analysis indicated that the major improvement in performance is related to the cathode kinetics in the as-prepared SWNH sample, while concerning the oxidized SWNH sample, the improvements are related to the electrokinetics in both anode and cathode electrodes. These improvements should be related with differences in the hydrophobic character between SWNH and carbon black.

Lipoprotein cofactors located in the outer membrane activate bacterial cell wall polymerases. Most bacteria surround themselves with a peptidoglycan PG exoskeleton synthesized by polysaccharide polymerases called penicillin-binding proteins PBPs.

Because they are the targets of penicillin and related antibiotics, the structure and biochemical functions of the PBPs have been extensively studied. Overall, our results indicate that PBP accessory proteins play a central role in PG biogenesis, and like the PBPs they work with, these factors are attractive targets for antibiotic development. Stabilization of glucose-C in microbial cell membranes PLFA and cell walls amino sugars evaluated by 13C-labelling in a field experiment.

Microorganisms control carbon C cycle and strongly contribute to formation of soil organic matter. Strong differences in the turnover of microbial groups and cellular compounds complicate the assessment of their contribution to microbial food webs and C sequestration in soil in situ. The uptake and incorporation of 13C labeled glucose by microbial groups were traced during 50 days after the labeling under field conditions.

This allowed tracing C in microbial groups as well as cellular compounds. Such long cytosol MRT depends on its heterogeneous composition, which includes high and low molecular weight organics. Amino sugars were mainly originated from microbial residues and thus, observation periods higher than 1 year are required for estimation of their MRT.

Relative 13C incorporation into amino sugars of living microorganisms showed only 0. Therefore, the turnover of cell membrane components is two times faster than that of cell walls , even in living microorganisms.

Consequently, bacteria contribute more to the decomposition of low molecular weight organics, whereas fungi consume bacterial products or necromass and contribute more to long-term C stabilisation. Thus, tracing of 13C in cellular. Hydroxylation of multi- walled carbon nanotubes: Enhanced biocompatibility through reduction of oxidative stress initiated cell membrane damage, cell cycle arrestment and extrinsic apoptotic pathway.

Modification of CNTs with hydroxyl group promotes their applications in biomedical area. However, the impact of hydroxylation on their biocompatibility is far from being completely understood. More interestingly, MWCNTs-OH exhibited significantly lower tendency to activate caspase-8, a key molecule involved in the extrinsic apoptotic pathway. Arabidopsis NDR1 is an integrin-like protein with a role in fluid loss and plasma membrane-cell wall adhesion. Whereas the genetic requirement for NDR1 in plant disease resistance signaling has been detailed, our study focuses on determining a global, physiological role for NDR1.

Specific protein motifs also point to a degree of homology with mammalian integrins, well-characterized proteins involved in adhesion and signaling. This structural homology led us to examine a physiological role for NDR1 in preventing fluid loss and maintaining cell integrity through plasma membrane-cell wall adhesions.

Our results show a substantial alteration in induced i. As an extension of these analyses, using a combination of genetic and cell biology-based approaches, we have identified a role for NDR1 in mediating plasma membrane-cell wall adhesions. Taken together, our data point to a broad role for NDR1 both in mediating primary cellular functions in Arabidopsis through maintaining the integrity of the cell wall -plasma membrane connection and as a key signaling component of these responses during pathogen infection.

Fungal cell wall organization and biosynthesis. The composition and organization of the cell walls from Saccharomyces cerevisiae, Candida albicans, Aspergillus fumigatus, Schizosaccharomyces pombe, Neurospora crassa, and Cryptococcus neoformans are compared and contrasted. A comparison of these cell walls shows that there is a great deal of variability in fungal cell wall composition and organization. However, in all cases, the cell wall components are cross-linked together to generate a cell wall matrix.

The biosynthesis and properties of each of the major cell wall components are discussed. The chitin and glucans are synthesized and extruded into the cell wall space by plasma membrane -associated chitin synthases and glucan synthases. The glycoproteins are synthesized by ER-associated ribosomes and pass through the canonical secretory pathway. Over half of the major cell wall proteins are modified by the addition of a glycosylphosphatidylinositol anchor.

The cell wall glycoproteins are also modified by the addition of O-linked oligosaccharides, and their N-linked oligosaccharides are extensively modified during their passage through the secretory pathway. These cell wall glycoprotein posttranslational modifications are essential for cross-linking the proteins into the cell wall matrix.

Cross-linking the cell wall components together is essential for cell wall integrity. The activities of four groups of cross-linking enzymes are discussed. Cell wall proteins function as cross-linking enzymes, structural elements, adhesins, and environmental stress sensors and protect the cell from environmental changes. Cell wall proteins are essential constituents of plant cell walls ; they are involved in modifications of cell wall components, wall structure, signaling and interactions with plasma membrane proteins at the cell surface.

The application of proteomic approaches to the cell wall compartment raises important questions: What kinds of proteins can be found in Arabidopsis walls? Are some of them unexpected? What sort of post-translational modifications have been characterized in cell wall proteins to date? The purpose of this review is to discuss the experimental results obtained to date using proteomics, as well as some of the new questions challenging future research. Mechanism of anchoring of OmpA protein to the cell wall peptidoglycan of the gram-negative bacterial outer membrane.

The outer membrane protein A OmpA plays important roles in anchoring of the outer membrane to the bacterial cell wall. However, there is a paucity of information on the structural aspects of the mechanism of PGN recognition by OmpA-like domains. To elucidate this molecular recognition process, we solved the high-resolution crystal structure of an OmpA-like domain from Acinetobacter baumannii bound to diaminopimelate DAP , a unique bacterial amino acid from the PGN.

These structural data provide a detailed glimpse of how the anchoring of OmpA to the cell wall of gram-negative bacteria takes place in a DAP-dependent manner. The pit membrane PM is a primary cell wall barrier that separates adjacent xylem water conduits, limiting the spread of xylem-localized pathogens and air embolisms from one conduit to the next.

This paper provides a characterization of the size of the pores in the PMs of grapevine Vitis vinifera. Stems were infused with pressurized water and flow rates were determined; gold particles of known size were introduced with the water to assist in determining the size of PM pores. The possibility that cell wall -degrading enzymes could alter the pore sizes, thus facilitating the ability of X.

Two cell wall -degrading enzymes likely to be produced by X. Scanning electron microscopy of control and enzyme-infused stem segments revealed that the combination of enzymes opened holes in PMs, probably explaining enzyme impacts on PMP and how a small X. Cell wall -degrading enzymes enlarge the pore size of intervessel pit membranes in healthy and Xylella fastidiosa-infected grapevines.

The effect of introducing trans-1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid CDTA , oligogalacturonides, and polygalacturonic acid into stems on water flux via the xylem was also measured. Mechanism of action of Spanish oregano, Chinese cinnamon, and savory essential oils against cell membranes and walls of Escherichia coli O H7 and Listeria monocytogenes.

The mechanism of the antimicrobial action of Spanish oregano Corydothymus capitatus , Chinese cinnamon Cinnamomum cassia , and savory Satureja montana essential oils against cell membranes and walls of bacteria was studied by the measurement of the intracellular pH and ATP concentration, the release of cell constituents, and the electronic microscopy observations of the cells when these essential oils at their MICs were in contact with Escherichia coli O Treatment with these essential oils at their MICs affected the membrane integrity of bacteria and induced depletion of the intracellular ATP concentration.

Spanish oregano and savory essential oils, however, induced more depletion than Chinese cinnamon oil. An increase of the extracellular ATP concentration was observed only when Spanish oregano and savory oils were in contact with E. Also, a significantly higher P cell constituent release was observed in the supernatant when E.

Chinese cinnamon oil was more effective to reduce significantly the intracellular pH of E. H7, whereas Chinese cinnamon and Spanish oregano decreased more significantly the intracellular pH of L. Electronic microscopy observations revealed that the cell membrane of both treated bacteria was significantly damaged. These results suggest that the cytoplasmic membrane is involved in the toxic action of essential oils.

In chemical terms, wood is best defined as a three-dimensional biopolymer composite composed of an interconnected network of cellulose, hemicelluloses, and lignin with minor amounts of extractives and inorganics. The major chemical component of a living tree is water, but on a dryweight basis, all wood cell walls consist mainly of sugar-based polymers carbohydrates, Bacterial Cell Wall Components.

Bacterial cell -surface polysaccharides cells are surrounded by a variety of cell -surface structures that allow them to thrive in extreme environments. Components of the cell envelope and extracellular matrix are responsible for providing the cells with structural support, mediating intercellular communication, allowing the cells to move or to adhere to surfaces, protecting the cells from attack by antibiotics or the immune system, and facilitating the uptake of nutrients.

Some of the most important cell wall components are polysaccharide structures. This review discusses the occurrence, structure, function, and biosynthesis of the most prevalent bacterial cell surface polysaccharides: The roles of these polysaccharides in medicine, both as drug targets and as therapeutic agents, are also described. Isolation of plant cell wall proteins.

The quality of a proteomic analysis of a cell compartment strongly depends on the reliability of the isolation procedure for the cell compartment of interest.

Plant cell walls possess specific drawbacks: Three categories of CWP are distinguished: Two alternative protocols are decribed for cell wall proteomics: These protocols give very low levels of contamination by intracellular proteins. Their application should lead to a realistic view of the cell wall proteome at least for labile and weakly bound CWP extractable by salts. Cell Wall Assembly in Fucus Zygotes. Fertilization triggers the assembly of a cell wall around the egg cell of three brown algae, Fucus vesiculosus, F.

New polysaccharide polymers are continually being added to the cell wall during the first 24 hours of synchronous embryo development.

This wall assembly involves the extracellular deposition of fibrillar material by cytoplasmic vesicles fusing with the plasma membrane. One hour after fertilization a fragmented wall can be isolated free of cytoplasm and contains equal amounts of cellulose and alginic acid with no fucose-containing polymers fucans present.

Birefringence of the wall caused by oriented cellulose microfibrils is not detected in all zygotes until 4 hours, at which time intact cell walls can be isolated that retain the shape of the zygote. These walls have a relatively low ratio of fucose to xylose and little sulfate when compared to walls from older embryos.

When extracts of walls from 4-hour zygotes are subjected to cellulose acetate electrophoresis at pH 7, a single fucan F1 can be detected.

By 12 hours, purified cell walls are composed of fucans containing a relatively high ratio of fucose to xylose and high levels of sulfate, and contain a second fucan F2 which is electrophoretically distinct from F1.

F2 appears to be deposited in only a localized region of the wall , that which elongates to form the rhizoid cell. Throughout wall assembly, the polyuronide block co-polymer alginic acid did not significantly vary its mannuronic M to guluronic G acid ratio 0. From 6 to 24 hours of embryo development, the proportion of the major polysaccharide components found in purified walls is stable.

During the extracellular assembly of this wall , the intracellular levels of the storage glucan laminaran. Two bean cell wall proteins more abundant during water deficit are high in proline and interact with a plasma membrane protein. Two antigenically related glycoproteins, called p33 and p36, accumulate in the soluble fraction of the cell wall in response to water deficit in Phaseolus vulgaris.

In this report, we show that p33 and p36 are able to adhere to leaf protoplasts, and that they bind to plasma membrane PM vesicles in a divalent cation-dependent manner.

Binding assays demonstrate that both proteins specifically bind to an 80 kDa PM protein. This binding is competed with a peptide that contains the RGD motif, as well as with fibronectin, which also includes this sequence, suggesting that the 80 kDa PM protein has an integrin-like function whose natural ligands are p33 and p This is the first case where a PM ligand for a higher plant cell wall protein has been identified. Microsporidia are obligate intracellular parasites, and a derivative of fungi, which harbor a rigid spore wall to resist adverse environmental pressures.

The spore wall protein, which is thought to be the first and direct protein interacting with the host cell , may play a key role in the process of microsporidia infection. The protein also has 6 heparin-binding motifs which are known to interact with extracellular glycosaminoglycans.

Syntenic analysis indicated that gene loci of Nbhswp11 are conserved and syntenic between Nosema bombycis and Nosema ceranae. Nbhswp11 was transcribed throughout the entire life stages, and gradually increased during days, in a silkworm that was infected by N.

Western blotting analysis displayed NbHSWP11 expressed in the total mature spore proteins and spore coat proteins. Indirect immunofluorescence assay revealed NbHSWP11 located at the spore wall of mature spores and the spore coats. Furthermore, immune electron microscopy showed that NbHSWP11 localized in the cytoplasm of the sporont.

Within the developmental process of N. However, most of NbHSWP11 distributes on the membraneous structures of the sporoblast and mature spore. In addition, using a host cell binding assay, native protein NbHSWP11 in the supernatant of total soluble mature spore proteins is shown to bind to the host cell BmE surface. Finally, an antibody blocking assay showed that purified rabbit antibody of NbHSWP11 inhibits spore adherence and decreases the adherence rate of spores by Diffusion nearby elastic cell membranes.

The physical approach of a small particle to the cell membrane represents the crucial step before active internalization and is governed by Brownian diffusion. Using a fully analytical theory, we show that the stretching and bending of cell membranes induces a long-lived subdiffusive behavior on the nearby particle.

Such behavior is qualitatively different from the normal diffusion in a bulk fluid or near a hard- wall. Moreover, we investigate the hydrodynamic interaction between two particles finding that the steady motion of two particles towards an elastic membrane possessing only shearing resistance leads to attractive interaction in contrast to the hard- wall case where the interaction is known to be repulsive.

Our analytical predictions are compared with boundary-integral simulations where an excellent agreement is obtained. The role of Lactobacillus cell wall components in the protection against pathogen infection in the gut is still largely unexplored. We have previously shown that L. We have also demonstrated that L. In the present study, we investigated the role of L. Purified cell wall fragments CWF from L.

Tight junction TJ and adherens junction AJ proteins were analyzed by immunofluorescence and Western blot. Membrane permeability was determined by phenol red passage. Phosphorylated pNF-kB was measured by Western blot. The results indicate that the various components of L. Dynamics of cell wall structure in Saccharomyces cerevisiae. The cell wall of Saccharomyces cerevisiae is an elastic structure that provides osmotic and physical protection and determines the shape of the cell.

The inner layer of the wall is largely responsible for the mechanical strength of the wall and also provides the attachment sites for the proteins that form the outer layer of the wall. Here we find among others the sexual agglutinins and the flocculins. The outer protein layer also limits the permeability of the cell wall , thus shielding the plasma membrane from attack by foreign enzymes and membrane -perturbing compounds.

The main features of the molecular organization of the yeast cell wall are now known. Importantly, the molecular composition and organization of the cell wall may vary considerably.

For example, the incorporation of many cell wall proteins is temporally and spatially controlled and depends strongly on environmental conditions. Similarly, the formation of specific cell wall protein-polysaccharide complexes is strongly affected by external conditions.

This points to a tight regulation of cell wall construction. Indeed, all five mitogen-activated protein kinase pathways in bakers' yeast affect the cell wall , and additional cell wall -related signaling routes have been identified. Finally, some potential targets for new antifungal compounds related to cell wall construction are discussed.

Composite fuel cell membranes. A bilayer or trilayer composite ion exchange membrane is described suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell.

In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers. A bilayer or trilayer composite ion exchange membrane suitable for use in a fuel cell.

Red cell membrane disorders. Significant advances have been made in our understanding of the structural basis for altered cell function in various inherited red cell membrane disorders with reduced red cell survival and resulting hemolytic anemia. The current review summarizes these advances as they relate to defining the molecular and structural basis for disorders involving altered membrane structural organization hereditary spherocytosis [HS] and hereditary elliptocytosis [HE] and altered membrane transport function hereditary overhydrated stomatocytosis and hereditary xerocytosis.

Mutations in genes encoding membrane proteins that account for these distinct red cell phenotypes have been identified. These molecular insights have led to improved understanding of the structural basis for altered membrane function in these disorders. Weakening of vertical linkage between the lipid bilayer and spectrin-based membrane skeleton leads to membrane loss in HS. In contrast, weakening of lateral linkages among different skeletal proteins leads to membrane fragmentation and decreased surface area in HE.

The degrees of membrane loss and resultant increases in cell sphericity determine the severity of anemia in these two disorders. Splenectomy leads to amelioration of anemia by increasing the circulatory red cell life span of spherocytic red cells that are normally sequestered by the spleen. Disordered membrane cation permeability and resultant increase or decrease in red cell volume account for altered cellular deformability of hereditary overhydrated stomatocytosis and hereditary xerocytosis, respectively.

Importantly, splenectomy is not beneficial in these two membrane transport disorders and in fact contraindicated due to severe postsplenectomy thrombotic complications. Many Gram-negative and Gram-positive bacteria recycle a significant proportion of the peptidoglycan components of their cell walls during their growth and septation.

In many—and quite possibly all—bacteria, the peptidoglycan fragments are recovered and recycled. While cell-wall recycling is beneficial for the recovery of resources, it also serves as a mechanism to detect cell -wall—targeting antibiotics and to regulate resistance mechanisms.

The involvement of peptidoglycan recycling with resistance regulation suggests that inhibitors of the enzymes involved in the recycling might synergize with cell-wall -targeted antibiotics. We describe the key steps of cell-wall remodeling and recycling, the regulation of resistance mechanisms by cell-wall recycling, and recent advances toward the discovery of cell-wall recycling inhibitors.

Involvement of membrane sterols in hypergravity-induced modifications of growth and cell wall metabolism in plant stems. Roles and regulation of plant cell walls surrounding plasmodesmata. In plants, the intercellular transport of simple and complex molecules can occur symplastically through plasmodesmata.

These are membranous channels embedded in cell walls that connect neighbouring cells. The properties of the cell walls surrounding plasmodesmata determine their transport capacity and permeability.

These cell wall micro-domains are enriched in callose and have a characteristic pectin distribution. Cell wall modifications, leading to changes in plasmodesmata structure, have been reported to occur during development and in response to environmental signals. Cell wall remodelling enzymes target plasmodesmata to rapidly control intercellular communication in situ. Here we describe current knowledge on the composition of cell walls at plasmodesmata sites and on the proteins and signals that modify cell walls to regulate plasmodesmata aperture.

Plant cell wall signalling and receptor-like kinases. Communication between the extracellular matrix and the cell interior is essential for all organisms as intrinsic and extrinsic cues have to be integrated to co-ordinate development, growth, and behaviour. This applies in particular to plants, the growth and shape of which is governed by deposition and remodelling of the cell wall , a rigid, yet dynamic, extracellular network. It is thus generally assumed that cell wall surveillance pathways exist to monitor the state of the wall and, if needed, elicit compensatory responses such as altered expression of cell wall remodelling and biosynthesis genes.

Here, I highlight recent advances in the field of cell wall signalling in plants, with emphasis on the role of plasma membrane receptor-like kinase complexes. In addition, possible roles for cell wall -mediated signalling beyond the maintenance of cell wall integrity are discussed. Bacteria grow and divide without loss of cellular integrity. Full Text Available Only a limited spectrum of active substances is available for weed control in leguminous plants and sunflowers. Since the official plant protection service in Brandenburg conducts herbicide field trials in these crop species in the region around Drebkau for the investigation of practicable approaches for control of Ambrosia artemisiifolia.

For the cultivation of lupins only pre-emergence herbicides are registered. Due to the high density of A. Likewise, the performance of authorised herbicides in sunflowers is insufficient. In the region concerned cultivation of grain legumes and sunflowers is limited in areas with high coverage rate of A. Full Text Available Since the beginning of common ragweed registration in North Rhine-Westphalia in there have been ragweed records, among them 31 populations with more than individuals.

Common ragweed is not yet established in North Rhine-Westphalia but seems to do very well on sandy soils in the Lowland. North Rhine-Westphalia is tackling common ragweed in an early stage of invasion and will continue the strategy of rapid response to achieve a total eradication.

Thirty-three countries have already signed the Memorandum of Understanding and over researchers with specialists in weed research, invasive alien species management, ecology, aerobiology, allergology and economics are registered participants of SMARTER. COST Actions interlink nationally funded research projects and enable and finance conferences, working groups, training schools and research exchanges.

SMARTER aims to initiate and develop long-term and sustainable control methods, to integrate these into existing mechanical and chemical control measures, and to quantify the success of these measures both for agriculture and health. The focus is on biological control methods with insects and fungi especially using alien species from the area of origin of Ambrosia and vegetation management to achieve a competitive plant cover. For this, we develop and parameterize models, starting from the population dynamics of Ambrosia , on the impact of control measures on the frequency and distribution of Ambrosia and finally on pollen counts and allergy occurrences, each with both ecological and economic components.

The necessary data are derived from the many experiments that we carry out in well-coordinated studies across Europe. SMARTER will allow the various stakeholders to select optimal habitat- and region-specific combinations of control methods. After an introduction and overview of the structure and the state of the Action, we briefly describe two planned activities typical for our Action, a study on the population dynamics of Ambrosia in different climates and habitats in Europe as a basis for estimating the efficiency of control measures, and an interdisciplinary study to clarify the impact the of North American native Ambrosia leaf beetle Ophraella communa Coleoptera.

Climate-change-induced range shifts of three allergenic ragweeds Ambrosia L. Full Text Available Invasive allergenic plant species may have severe health-related impacts. In this study we aim to predict the effects of climate change on the distribution of three allergenic ragweed species Ambrosia spp. We estimate that by year , the distribution range of all three ragweed species increases towards Northern and Eastern Europe under all climate scenarios.

We conclude that areas in Europe affected by severe ragweed associated allergy problems are likely to increase substantially by year , affecting millions of people. To avoid this, management strategies must be developed that restrict ragweed dispersal and establishment of new populations.

Precautionary efforts should limit the spread of ragweed seeds and reduce existing populations. Only by applying cross-countries management plans can managers mitigate future health risks and economical consequences of a ragweed expansion in Europe. Invasive allergenic plant species may have severe health-related impacts. We quantify the extent of the increase in 'high allergy risk' HAR areas, i. Effects of climate change and seed dispersal on airborne ragweed pollen loads in Europe.

Common ragweed Ambrosia artemisiifolia is an invasive alien species in Europe producing pollen that causes severe allergic disease in susceptible individuals. Ragweed plants could further invade European land with climate and land-use changes. However, airborne pollen evolution depends not only on plant invasion, but also on pollen production, release and atmospheric dispersion changes. To predict the effect of climate and land-use changes on airborne pollen concentrations, we used two comprehensive modelling frameworks accounting for all these factors under high-end and moderate climate and land-use change scenarios.

We estimate that by airborne ragweed pollen concentrations will be about 4 times higher than they are now, with a range of uncertainty from 2 to 12 largely depending on the seed dispersal rate assumptions. About a third of the airborne pollen increase is due to on-going seed dispersal, irrespective of climate change.

The remaining two-thirds are related to climate and land-use changes that will extend ragweed habitat suitability in northern and eastern Europe and increase pollen production in established ragweed areas owing to increasing CO2.

Therefore, climate change and ragweed seed dispersal in current and future suitable areas will increase airborne pollen concentrations, which may consequently heighten the incidence and prevalence of ragweed allergy.

Full Text Available Since the common ragweed , Ambrosia artemisiifolia , which was introduced from North America has also been found in Bavaria in larger stocks and has an increasing tendency to spread. After receiving the report of the Bavarian Ministry of Health, the Bavarian Parliament addressed the implications for health. There was consensus across all political groups to combat the plant. The 96 district administration authorities, which each have a trained ragweed officer, report to the registration office on new verified ragweed locations with more than plants.

The reports of common ragweed stands are filed by citizens or through research by the district administration authorities, who are also responsible for supporting the fight against stocks.

On behalf of the Bavarian Ministry of Health, the Working Group Biodiversity monitors the situation and finds many new locations. Since , new common ragweed stocks were registered.

After control measures there are currently known remaining stocks. Since , however, the populated area has tripled.

This means that the control measures need further improvement. This is especially true for the common ragweed stocks along roadsides where the plants have increased massively in recent years. Sustainable control has proved to be particularly difficult. Ragweed -induced allergic rhinoconjunctivitis: Ragweed -induced allergic rhinoconjunctivitis has long been seen as a major immunologic condition in Northern America with high exposure and sensitization rates in the general population.

The invasive occurrence of ragweed A. Possible explanations for its worldwide spread are climate change and urbanization, as well as pollen transport over long distances by globalized traffic and winds. Due to the increasing disease burden worldwide, and to the lack of a current and comprehensive overview, this study aims to review the current and emerging treatment options for ragweed -induced rhinoconjunctivitis. Sound clinical evidence is present for the symptomatic treatment of ragweed -induced allergic rhinoconjunctivitis with oral third-generation H1-antihistamines and leukotriene antagonists.

The topical application of glucocorticoids has also been efficient in randomized controlled clinical trials. Combined approaches employing multiple agents are common. The mainstay of causal treatment to date, especially in Northern America, is subcutaneous immunotherapy with the focus on the major allergen, Amb a 1. Beyond this, growing evidence from several geographical regions documents the benefit of sublingual immunotherapy.

Future treatment options promise more specific symptomatic treatment and fewer side effects during causal therapy. Novel antihistamines for symptomatic treatment are aimed at the histamine H3-receptor. New adjuvants with toll-like receptor 4 activity or the application of the monoclonal anti-immunoglobulin E antibody, omalizumab, are supposed to enhance conventional immunotherapy. An approach targeting toll-like receptor 9 by. Full Text Available The European Union handed over the regulation of common ragweed Ambrosia artemisiifolia to the member states.

Austrian administration started to ask for control measures, i. Any sustainable control measure must focus on the reduction of seeds produced by the annual ragweed. Seed bank dimension of ragweed turned out to be a good evaluation tool for any control measure.

To evaluate the importance of different spreading mechanisms of dispersal, a need for serious figures can be stated. Based on our seed trap experiments and comparable slip stream experiments by German botanists, the efficiency of vehicles in spreading ragweed over long distances was low. However, machines used by road services cutter, moulder turned out to spread thousands of seeds. Besides, there is serious indication that trucking agricultural food and seeds over long distances is relevant for ragweed seed dispersal.

Dispersal of thousands of ragweed seeds from contaminated agricultural fields to fields not yet infested is caused by harvesters and other agricultural machines.

Regulations to reduce the ragweed load in traded agricultural goods are to be implemented in future. Small populations of ragweed should be simply uprooted and composted as long as they bear no flowers. Various possibilities are known for control of common ragweed in agricultural fields with mechanical and chemical methods. Limits are set in sunflowers because sunflower and ragweed are botanically related. The legal obligation of reporting and control — introduced in Switzerland a couple of years ago — allowed the development of specific distribution maps and enhanced the quality of control measures.

Facts and figures from the Canton of Geneva prove that the ragweed invasion has been stopped, but the species is not eradicated. The results of Geneva represent the results of good ragweed control in the whole country.

Beside agriculture, traffic infrastructure, building sites, gravel pits and urban park and garden areas are sensible to ragweed invasion. The responsibility of individuals helps to improve control efficiency even if financial funds are small. A sustainable control success depends on the efficiency to hamper seed production. The reduction of pollen quantity in the air in a long term is part of the earnings for the control effort.

Actually, the publicity of common ragweed is fed by specialist information and its distribution in the media. It would be an interesting task to develop in our fast moving era an awareness level comparable to that of the stinging nettle.

Effect of heavy metals on seed germination and seedling growth of common ragweed and roadside ground cover legumes. It creates empty niches vulnerable to weed establishment such as common ragweed Ambrosia artemisiifolia. We hypothesized that heavy metal stresses may drive such species shifts along roadside edges.

A growth chamber experiment was conducted to assess effects of metals Zn, Pb, Ni, Cu, and Cd on germination and seedling behaviors of roadside weed A. All metals inhibited T. Low levels of Pb and Ni promoted germination initiation of A. Metal additions hindered seedling growth of all test species, and the inhibitory effect on the belowground growth was greater than on the aboveground growth.

Seedling mortality was lowest in A. In conclusion, the successful establishment of A. The findings also revealed that L. Full Text Available Identifying the sensitive habitats with high invasibility is critical for management of biological invasion. Ragweed Ambrosia artemisiifolia Linn. The experiment took ragweek as a model invader to reveal the community invisibility of different habitats.

The results suggested that the presence of native species had strong negative effects on the performance of the invader species.

The presence of native species occupied the niche space and left few empty niches for the colonization of the invaders. The results revealed that planting native species in bare soils, and maintaining the native communities with high diversity, was effective strategies to control the invasion of exotic species. The present situation of the plant was analyzed in Qinhuangdao region, and the new campus was taken as an example to inves-tigate the effects of human activity disturbance on A.

The invasiveness of A. In present, the plant was a community construction species in this region, and showed no invasion. The investigated results showed that A. However, in the habitat disturbed by human activities, the plant had relatively high advantage. Therefore, excessive human activity disturbance should be prevented to control the invasive plant, by which to protect the local ecological environment.

Ragweed subpollen particles of respirable size activate human dendritic cells. Full Text Available Ragweed Ambrosia artemisiifolia pollen grains, which are generally considered too large to reach the lower respiratory tract, release subpollen particles SPPs of respirable size upon hydration. In this study, we examined whether exposure to SPPs initiates the activation of human monocyte-derived dendritic cells moDCs. Collectively, our data suggest that inhaled ragweed SPPs are fully capable of activating dendritic cells DCs in the airways and SPPs' NAD PH oxidase activity is involved in initiation of adaptive immune responses against innocuous pollen proteins.

Characterizing restriction enzyme-associated loci in historic ragweed Ambrosia artemisiifolia voucher specimens using custom-designed RNA probes. Population genetic studies of non-model organisms frequently employ reduced representation library RRL methodologies, many of which rely on protocols in which genomic DNA is digested by one or more restriction enzymes.

However, because high molecular weight DNA is recommended for these protocol Ambrosia is a kind of invasive alien weed, whose invasion not only threatens native biodiversity and ecosystems, but also causes considerable economic loss.

In order to control the damage of Ambrosia effectively, on the basis of introducing mechanical, chemical and biological control methods, the insufficiencies of them were clarified and an integrated control measure was proposed.

Exotic plant invasion presents a serious threat to native ecosystem structure and function. Little is known about the role of soil microbial communities in facilitating or resisting the spread of invasive plants into native communities. The purpose of this research is to understand how the invasive annual plantAmbrosiaartemisiifoliaL. The soil characteristics of different areas invaded by A. Greenhouse experiments were designed to assess the effect ofA.

The results showed that the soil organic C content was the highest in heavily invaded sites, the lowest in native plant sites, and intermediate in newly invaded sites. Soil available N, P and K concentrations in heavily invaded site were 2.

Soil pH decreased asA. The soil microbial community structure was clearly separated in the three types of sites, andA. Soil biota of invaded sites inhibits growth of co-occurring plants Galinsoga parvilfora Cav. Results of the present study indicated thatA. Northern ragweed ecotypes flower earlier and longer in response to elevated CO2: Significant changes in plant phenology and flower production are predicted over the next century, but we know relatively little about geographic patterns of this response in many species, even those that potentially impact human wellbeing.

We tested for variation in flowering responses of the allergenic plant, Ambrosia artemisiifolia common ragweed. We hypothesized that northern ecotypes adapted to shorter growing seasons would flower earlier than their southern counterparts, and thus disproportionately allocate carbon gains from CO2 to reproduction. As predicted, latitude of origin and carbon dioxide level significantly influenced the timing and magnitude of flowering. Reproductive onset occurred earlier with increasing latitude, with concurrent increases in the number of flowers produced.

Elevated carbon dioxide resulted in earlier reproductive onset in all ecotypes, which was significantly more pronounced in the northern populations. We interpret our findings as evidence for ecotypic variation in ragweed flowering time, as well in responses to CO2. Thus, the ecological and human health implications of common ragweed 's response to global change are likely to depend on latitude.

We conclude that increased flower production, duration, and possibly pollen output, can be expected in Northeastern United States with rising levels of CO2. The effects are likely, however, to be most significant in northern parts of the region. The invasive alien species Ambrosia artemisiifolia common or short ragweed is increasing its range in Europe.

In the UK and the Netherlands, airborne concentrations of Ambrosia pollen are usually low. However, more than 30 Ambrosia pollen grains per cubic metre of air above the level capable to trigger allergic symptoms were recorded in Leicester UK and Leiden NL on 4 and 5 September The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the episode could be the result of long distance transport, to identify the potential sources of these pollen grains and to describe the conditions that facilitated this possible long distance transport.

Airborne Ambrosia pollen data were collected at 10 sites in Europe. Back trajectories calculated at Leicester and Leiden show that higher altitude air masses m originated from source areas on the Pannonian Plain and Ukraine.

The study indicates that the Ambrosia pollen grains recorded during the episode in Leicester and Leiden were probably not produced by local sources but transported long distances from potential source regions in east Europe, i. Ambrosia airborne pollen concentration modelling and evaluation over Europe. Native from North America, Ambrosia artemisiifolia L.

Common Ragweed is an invasive annual weed introduced in Europe in the mid-nineteenth century. It has a very high spreading potential throughout Europe and releases very allergenic pollen leading to health problems for sensitive persons. Because of its health effects, it is necessary to develop modelling tools to be able to forecast ambrosia air pollen concentration and to inform allergy populations of allergenic threshold exceedance.

To calculate and predict airborne concentrations of ambrosia pollen, a chain of models has been built. The detailed methodology, formulations and input data will be presented. A set of simulations has been performed to simulate airborne concentrations of pollens over long time periods on a large European domain.

Hindcast simulations - driven by ERA-Interim re-analyses are designed to best simulate past periods airborne pollens. The modelled pollen concentrations are calibrated with observations and validated against additional observations. Then, year long historical simulations - are carried out using calibrated ambrosia density distribution and climate model-driven weather in order to serve as a control simulation for future scenarios. By comparison with multi-annual observed daily pollen counts we have shown that the model captures well the gross features of the pollen.

Modelling the introduction and spread of non-native species: Biological invasions are a major driver of global change, for which models can attribute causes, assess impacts and guide management. However, invasion models typically focus on spread from known introduction points or non-native distributions and ignore the transport processes by which species arrive.

Here, we developed a simulation model to understand and describe plant invasion at a continental scale, integrating repeated transport through trade pathways, unintentional release events and the population dynamics and local anthropogenic dispersal that drive subsequent spread. We used the model to simulate the invasion of Europe by common ragweed Ambrosia artemisiifolia , a globally invasive plant that causes serious harm as an aeroallergen and crop weed.

Simulations starting in accurately reproduced ragweed 's current distribution, including the presence of records in climatically unsuitable areas as a result of repeated introduction. Furthermore, the model outputs were strongly correlated with spatial and temporal patterns of ragweed pollen concentrations, which are fully independent of the calibration data.

The model suggests that recent trends for warmer summers and increased volumes of international trade have accelerated the ragweed invasion. For the latter, long distance dispersal because of trade within the invaded continent is highlighted as a key invasion process, in addition to import from the native range.

Biosecurity simulations, whereby transport through trade pathways is halted, showed that effective control is only achieved by early action targeting all relevant pathways. We conclude that invasion models would benefit from integrating introduction processes transport and release with spread dynamics, to better represent propagule pressure from native sources as well as mechanisms for long-distance dispersal within invaded continents. Ultimately, such integration may facilitate better prediction of spatial and temporal variation in invasion.

Ragweed pollen production and dispersion modelling within a regional climate system, calibration and application over Europe. Its pollen can be transported over large distances and has been recognized as a significant cause of hay fever and asthma D'Amato et al. To simulate production and dispersion of common ragweed pollen, we implement a pollen emission and transport module in the Regional Climate Model RegCM version 4 using the framework of the Community Land Model CLM version 4.

In this online approach pollen emissions are calculated based on the modelling of plant distribution, pollen production, species-specific phenology, flowering probability, and flux response to meteorological conditions.

A pollen tracer model is used to describe pollen advective transport, turbulent mixing, dry and wet deposition. The model is then applied and evaluated on a European domain for the period To reduce the large uncertainties notably due to the lack of information on ragweed density distribution, a calibration based on airborne pollen observations is used. Accordingly a cross validation is conducted and shows reasonable error and sensitivity of the calibration. Resulting simulations show that the model captures the gross features of the pollen concentrations found in Europe, and reproduce reasonably both the spatial and temporal patterns of flowering season and associated pollen concentrations measured over Europe.

The model can explain The correlation between simulated and observed daily concentrations time series reaches 0. Statistical scores show that the model performs better over the central Europe source region where pollen loads are larger and the model is better constrained. From these simulations health risks associated to common ragweed pollen. The airborne ragweed pollen spectrum was investigated in the air of Ankara, Turkey for aperiod of ten years using a Burkard seven-day volumetric recording trap.

In our study period,long distance transported Ambrosia pollen has been registered. Daily pollen levels varied from low to highin Burge's system. In last three years, the pollen concentration of Ambrosia showed a clear increasingtendency. Our results prove that ragweed pollen may be an important threat for ragweed sensitive patientsin Ankara city in near future.

Lifescience Database Archive English. Full Text Available c Spatial and temporal variations in airborne Ambrosia pollen in Europe. The goal of the present study is to provide a baseline for spatial and temporal variations in airborne Ambrosia pollen in Europe that can be used for the management and evaluation of this noxious plant. The study covers the full range of Ambrosia artemisiifolia L. Airborne Ambrosia pollen data for the principal flowering period of Ambrosia August-September recorded during a year period were obtained from monitoring sites.

The mean sum of daily average airborne Ambrosia pollen and the number of days that Ambrosia pollen was recorded in the air were analysed. The mean and standard deviation SD were calculated regardless of the number of years included in the study period, while trends are based on those time series with 8 or more years of data.

The direction of any trends varied locally and reflected changes in sources of the pollen, either in size or in distance from the monitoring station. Pollen monitoring is important for providing an early warning of the expansion of this invasive and noxious plant. The extraction of exotic plant ragweed Ambrosia artemisiifolia L. It can prevent the extraction of ragweed from inactivation,which could be easily caused by external condition such as illumination and temperature.

The microcapsule technique can improve the property of extraction. The results showed that the morphology of microcapsules was regular and integrated observed under scanning electron microscope SEM. Moreover,the core material was coated with shell material observed by the infrared spectrum analysis with Fourier transform infrared spectroscopy FTIR.

The association efficiency and loading capacity of the microcapsules determined by ultraviolet spectrophotometer were The medium diameter was And the results of thermogravimetric analysis TGA demonstrated that the thermal stability of the microcapsules was superior to the core material.

Consequently,the microcapsules with the extraction can avoid the unstable defect of the natural extraction. In addition,the activity was also lengthened by this technique. The occurrence of Ambrosia pollen in the atmosphere of Northwest Turkey: Ambrosia pollen was first reported as an important allergen in North America at the end of the nineteenth century, and many European countries have recently reported its increasing significance for pollen allergy.

The aims of this study were to determine whether the highly allergenic Ambrosia pollen recorded during the studied period could be the result of long-distance transport LDT and to identify the potential sources of Ambrosia pollen grains. The study investigates Ambrosia pollen episodes during the peak term of six yearly periods between and by examining source regions in Ambrosia pollen in Bursa, Turkey.

A volumetric trap was used for collecting the pollen samples, and the back-trajectory model was used to identify a potential source of atmospheric Ambrosia pollen. The days when pollen levels exceeded 30 P m-3 were computed, and clusters were shown on the figures. The study indicates that the Ambrosia pollen grains recorded during the episode in Bursa were not produced by local sources but transported long distances from potential source regions around the Azov Sea in Russia and Ukraine, Black Sea region of Turkey, Romania, and Bulgaria.

Note that atmospheric concentrations of Ambrosia pollen exceeded the clinical threshold during 28 days during the investigation period.

Taking into consideration the high allergenicity of Ambrosia pollen, the present findings suggest that the number of ragweed -sensitized individuals might increase in the near future in the region. Full Text Available From a medical perspective, introduction and spread of ragweed in Germany are a disaster.

The pollen of the species trigger allergic rhinitis and conjunctivitis that often lead to allergies against food items like celery or spices.

In some cases this can lead to allergic asthma that at first appears during the ragweed pollen season in September and October, but can later prevail during the whole year. In addition, touching the plant can result in contact dermatitis. From a medical point of view, halting the spread of ragweed is important and necessary. Analysis of high allergenicity airborne pollen dispersion: The appearance of ragweed pollen in the air became more frequent in northerly countries. Attention of allergologists and aerobiologists in these countries is focused on the phenomenon that Ambrosia plants found relatively sporadic but the amount of pollen is high in particular days.

Over the latter decade, a matter of particular concern has been Ambrosia pollen, whose appearance in the air is determined by the plants dispersing it and meteorological processes that alter pollen release, dissemination, transport or deposition on surfaces.

Pollen data used in this study were collected in three pollen-trapping sites in Lithuania. The data corresponding to years of pollen monitoring were documented graphically and evaluated statistically. Analysis of the pollen data suggests that although the number of ragweed plants identified has not increased over the latter decade, the total pollen count has been on the increase during the recent period.

The highest atmospheric pollen load is established on the last days of August and first days of September. We have established a regularity exhibiting an increase in ragweed pollen count conditioned by south-eastern winds in Lithuania.

The ex-periment took ragweek as a model invader to reveal the community invisibility of different habitats. The results revealed that planting native species in bare soils, and maintaining the native communities.

Plants remember past weather: After extreme dry wet summers or years, pollen production of different taxa may decrease increase substantially. Accordingly, studying effects of current and past meteorological conditions on current pollen concentrations for different taxa have of major importance. The purpose of this study is separating the weight of current and past weather conditions influencing current pollen productions of three taxa.

Two procedures, namely multiple correlations and factor analysis with special transformation are used. The year data sets include daily pollen counts of Ambrosia ragweed , Poaceae grasses and Populus poplar , as well as daily values of four climate variables temperature, relative humidity, global solar flux and precipitation.

Multiple correlations of daily pollen counts with simultaneous values of daily meteorological variables do not show annual course for Ambrosia , but do show definite trends for Populus and Poaceae. Results received using the two methods revealed characteristic similarities.

For all the three taxa, the continental rainfall peak and additional local showers in the growing season can strengthen the weight of the current meteorological elements. However, due to the precipitation, big amount of water can be stored in the soil contributing to the effect of the past climate elements during dry periods. Higher climate sensitivity especially water sensitivity of the herbaceous taxa Ambrosia and Poaceae can be definitely established compared to the arboreal Populus.

Separation of the weight of the current and past weather conditions for different taxa involves practical importance both for health care and agricultural production. Field and greenhouse experiments were conducted during and at Stoneville, MS to determine control of ragweed parthenium with several preemergence PRE and postemergence POST herbicides registered for use in corn, cotton, peanut, rice, and soybean.

Change in Ragweed Pollen Season, Environmental Protection Agency — This figure shows how the length of ragweed pollen season changed at 11 locations in the central United States and Canada between and Ambrosia beetles are being increasingly recognized as significant pests of field-grown ornamental nursery stock. Two species are especially problematic in ornamental nurseries, namely the black stem borer, Xylosandrus germanus, and the granulate ambrosia beetle, Xylosandrus crassiusculus.

Economic analysis of preventing introduction of ragweed in Denmark. Ragweed is an Invasive Alien Species natively growing in North America which is at risk of being introduced in Denmark thru import of bird seeds. The plant produces a high amount of pollen which causes allergy and asthma and is considered a very potent allergy source. It is estimated that An inordinate fondness for Fusarium: Phylogenetic diversity of fusaria cultivated by Euwallacea ambrosia beetles on avocado and other plant hosts.

Ambrosia beetle fungiculture represents one of the most ecologically and evolutionarily successful symbioses. Here we document the evolution of a clade within Fusarium associated with ambrosia beetles in the genus Euwallacea Coleoptera: Is ragweed pollen allergenicity governed by environmental conditions during plant growth and flowering?

However, how genotype and environment contribute to ragweed pollen allergenicity has still to be established. To throw some light on the factors governing allergenicity, in this work ragweed plants from three Regions Canada, France, Italy were grown in both controlled constant and standard environmental conditions seasonal changes in temperature, relative humidity and light.

Pollen from single plants was characterized for its allergenic potency and for the underlying regulation mechanisms by studying the qualitative and quantitative variations of the main isoforms of the major ragweed allergen Amb a 1. Results showed a statistically higher variability in allergenicity of pollen from standard conditions than from controlled conditions growing plants. This variability was due to differences among single plants, regardless of their origin, and was not ascribed to differences in the expression and IgE reactivity of individual Amb a 1 isoforms but rather to quantitative differences involving all the studied isoforms.

It suggests that the allergenic potency of ragweed pollen and thus the severity of ragweed pollinosis mainly depends on environmental conditions during plant growth and flowering, which regulate the total Amb a 1 content. Effects of photoperiod and temperature on reproductive diapause in Ophraella communa Coleoptera: Chrysomelidae , a potential biocontrol agent against Ambrosia artemisiifolia.

To investigate the seasonal adaptation strategies of Ophraella communa to new habitats,the effects and regulation mechanisms of photoperiod and temperature on the reproductive diapause in a population collected from Changsha,Hunan were examined. Adults showed obvious reproductive diapause,which was regulated by photoperiod and temperature.

The pre-oviposition period was significantly prolonged when the pupae and adults were transferred from long-days to short-days,but the day length influence was not obvious when they were transferred only in the adult stage. However,the fecundity dropped greatly no matter whether the photoperiod shifted to short-days only in the adult stage or whether the shift occurred in both the pupal and adult stage.

The fecundity was extremely low when photoperiod shifted from long-days to short-days in both pupal and adult stages. This was an indication that the pupal and adult stages were the photoperiod-sensitive stage for adult reproductive diapause.

This was especially true for the photoperiod in the pupal stage,which has a distinctly significant regulative effect on reproductive diapause. Additionally,this article also addresses the reason for different photoperiodic response patterns in reproductive diapause induction between the Changsha strain and the Tsukuba strain Japan of O.

Ragweed in France is a rather recent pollen which causes strong allergies on the populations concerned. This pollen, mainly located in the area Rhone-Alpes, extend more and more on totality of France.

Indeed, the pollinic data highlight the presence of ragweed on all the territory with very low, as for Brittany, to several hundreds grains in the area of Rhone-Alpes. So four towns of this area have followed closely the extend of this pollen during the year through five pollen-traps 2 for the town of Lyon.

The trap of Lyon I Gerland made it possible to follow temporal the extend of ragweed from to and the increase of the number of grains as that of the number of days with a significant allergic risk.

The study shows also the differences in quantity of pollens, the differences between the daily allergic risks of the five sites, as well as the differences, between the cities, of the number of days when the allergic risk is significant. It is necessary that pollen of ragweed can be followed closely because of its strong allergenic capacity, in the area of Rhone-Alpes, where the plant prevails mainly, but also on the totality of the own territory, this to supervise its evolution and the speed of proliferation of the plant.

Chemical ecology and lure development for redbay ambrosia beetle. The exotic redbay ambrosia beetle, Xyleborus glabratus Eichhoff, has become a serious invasive pest in the U.

Female beetles are the primary vectors of a pathogenic fungus Raffaelea lauricola that causes laurel wilt. This lethal vascular dise Ambrosia beetles associated with laurel wilt of avocado. Redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in near Savannah, Georgia. Laurel wilt has since spr The invasive redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in the U. Redbay Ambrosia Beetle xyleborus glabratus eichoff coleoptera: The redbay ambrosia beetle, Xyleborus glabratus Eichoff, and its associated fungus Raffaelea lauricola T.

Together, they cause a vascular wilt disease that is highly destructive to some species in the Lauraceae Fraedrich et al. Xyleborus glabratus is a member of the Chemical ecology of the redbay ambrosia beetle Xyleborus glabratus.

The redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-boring pest first detected in the U. Ethanol injection of ornamental trees facilitates testing insecticide efficacy against ambrosia beetles Coleoptera: Exotic ambrosia beetles are damaging pests in ornamental tree nurseries in North America.

The species Xylosandrus crassiusculus Motshulsky and Xylosandrus germanus Blandford are especially problematic. Management of these pests relies on preventive treatments of insecticides. However, field tests of recommended materials on nursery trees have been limited because of unreliable attacks by ambrosia beetles on experimental trees.

Ethanol-injection of trees was used to induce colonization by ambrosia beetles to evaluate insecticides and botanical formulations for preventing attacks by ambrosia beetles. Experiments were conducted in Ohio, Tennessee, and Virginia. Experimental trees injected with ethanol had more attacks by ambrosia beetles than uninjected control trees in all but one experiment.

Xylosandrus crassiusculus and X. In most experiments, attack rates declined 8 d after ethanol-injection. Ethanol-injection induced sufficient pressure from ambrosia beetles to evaluate the efficacy of insecticides for preventing attacks.

Trunk sprays of permethrin suppressed cumulative total attacks by ambrosia beetles in most tests. Trunk sprays of the botanical formulations Armorex and Veggie Pharm suppressed cumulative total attacks in Ohio. The bifenthrin product Onyx suppressed establishment of X. Substrate drenches and trunk sprays of neonicotinoids, or trunk sprays of anthranilic diamides or tolfenpyrad were not effective.

Ethanol-injection is effective for inducing attacks and ensuring pressure by ambrosia beetles for testing insecticide efficacy on ornamental trees. Chemical ecology and serendipity: Developing attractants for Florida ambrosia beetle pests. Two exotic ambrosia beetles have become established in southern Florida: Both pests vector pathogenic fungal symbionts; the former for laurel wilt and the latter for Fusarium dieback d Symbiont diversification in ambrosia beetles: Diversity of fungi associated with exotic scolytine beetles.

In virtually every forest habitat, ambrosia beetles Coleoptera: Scolytinae, Platypodinae plant and maintain symbiotic fungus gardens inside dead or dying wood. Some introduced ambrosia beetles aggressively attack live trees and can damage tree crops, lumber, and native woody plant t In children allergic to ragweed pollen, nasal inflammation is not influenced by monosensitization or polysensitization. In patients polysensitized to pollen allergens, the priming effect, by which the sensitivity of the nasal mucosa to an allergen is increased by the previous exposure to another allergen, is a known phenomenon.

This study was aimed at evaluating the degree of nasal inflammation, assessed by nasal cytology, in children with allergic rhinitis AR from ragweed pollen according to being monosensitized or polysensitized. The study included 47 children. Of them, 24 suffered from AR caused by sensitization to grass pollen and ragweed pollen group A and 23 were sensitized only to ragweed pollen group B.

In all patients, the severity of AR was assessed according to the Allergic Rhinitis and Its Impact on Asthma guidelines, and comorbidities were also evaluated. In group A, No significant difference was detected in the number of the considered comorbidities between the two groups. This document assesses and compares the environmental impacts of various alternatives for remedial action at the Ambrosia Lake uranium mill tailings site located near Ambrosia Lake, New Mexico.

The designated site covers acres and contains acres of tailings and some of the original mill structures. Remedial action must be performed in accordance with these standards and with the concurrence of the Nuclear Regulatory Commission. The proposed action is to stabilize the tailings at their present location by consolidating the tailings and associated contaminated materials into a recontoured pile. A radon barrier would be constructed over the pile and various erosion protection measures would be taken to assure the long-term stability of the pile.

Another alternative which would involve moving the tailings to a new location is also assessed in this document.

This alternative would generally involve greater short-term impacts and costs but would result in stabilization of the tailings at an undeveloped location. The no action alternative is also assessed in this document. T-cell repertoire in the blood and lungs of atopic asthmatics before and after ragweed challenge. T cells play a pivotal role in initiating and orchestrating allergic responses in asthma. The goal of this work was to learn whether ragweed challenge in the lungs alters the T-cell repertoire expressed in the blood and lungs of atopic asthmatics.

Analyses of cell numbers, differentials, and T-cell. Bark and the ambrosia beetles dig into host plants and live most of their lives in concealed tunnels. We assessed beetle community dynamics in tropical dry forest sites in early, intermediate, and late successional stages, evaluating the influence of resource availability and seasonal variations in guild structure. We collected a total of beetles from 23 species, including 14 bark beetle species, and 9 ambrosia beetle species.

Local richness of bark and ambrosia beetles was estimated at 31 species. Bark and ambrosia composition was similar over the successional stages gradient, and beta diversity among sites was primarily determined by species turnover, mainly in the bark beetle community. Bark beetle richness and abundance were higher at intermediate stages; availability of wood was the main spatial mechanism.

Climate factors were effectively non-seasonal. Ambrosia beetles were not influenced by successional stages, however the increase in wood resulted in increased abundance. We found higher richness at the end of the dry and wet seasons, and abundance increased with air moisture and decreased with higher temperatures and greater rainfall. In summary, bark beetle species accumulation was higher at sites with better wood production, while the needs of fungi host and air moisture , resulted in a favorable conditions for species accumulation of ambrosia.

The overall biological pattern among guilds differed from tropical rain forests, showing patterns similar to dry forest areas.

Co-occurrence of Artemisia and Ambrosia pollen seasons against the background of the synoptic situations in Poland. The Asteraceae family is one of the largest families, comprising 67 genera and species in Poland. However, only a few genera, including Artemisia and Ambrosia are potential allergenic sources. The aim of the study was to estimate how often and to what degree Artemisia and Ambrosia pollen seasons co-occur intensifying human health risk, and how synoptic situations influence frequency of days with high pollen concentrations of both taxa.

Artemisia and Ambrosia pollen data were collected, using the volumetric method, at 8 sites in Poland. Daily concentrations of Artemisia pollen equal to 30 grains or more and Ambrosia pollen equal to 10 grains or more were accepted as high values.

Concentrations of more than 10 pollen grains were defined as high in the case of Ambrosia because its allergenicity is considered higher. High concentrations were confronted with synoptic situations. Co-occurrence of Artemisia and Ambrosia pollen seasons is being found most often, when Ambrosia pollen season starts in the first half of August.

If it happens in the last 10 days of August high pollen concentrations of Artemisia and Ambrosia do not occur at the same days. The high Artemisia pollen concentrations occur, when continental or polar maritime old air masses inflow into Poland. The impact of air masses on high Ambrosia pollen concentrations depends on site localizations.

It is likely, that in the south-eastern part of Poland high Ambrosia pollen concentrations result from the pollen transport from east-south-south-westerly directions and the local sources.

Co-occurrence of both taxa pollen seasons depends on the air masses inflow and appears more often in a south-eastern part of Poland. Furthermore, we used two different meteorological data sets the global GDAS data set and from the WRF mesoscale model; the meteorological parameters were: U and V wind components, temperature and relative humidity into HYSPLIT to evaluate the influence of meteorological input on calculated trajectories for high concentration ragweed episodes.

The HYSPLIT simulations with two different meteorological inputs indicated that footprint studies on ragweed benefit from a higher resolution meteorological data sets. Suitability of California bay laurel and other species as hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetle. The redbay ambrosia beetle Xyleborus glabratus Eichhoff is a non-native vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern U.

Concern exists that X. Suitability of California bay laurel and other species as potential hosts for the non-native redbay ambrosia beetle and granulate ambrosia beetle.

The redbay ambrosia beetle Xyleborus glabratus Eichhoff is a non-native invasive forest pest and vector of the pathogen that causes laurel wilt, a deadly disease of trees in the family Lauraceae in the southeastern United States U.

Effect of tree species and end seal on attractiveness and utility of cut bolts to the redbay Ambrosia beetle and granulate Ambrosia beetle Coleoptera: The redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a non-native invasive pest and vector of the fungus that causes laurel wilt disease in certain trees of the family Lauraceae. This study assessed the relative attractiveness and suitability of cut bolts of several tree species to X. In , female X.

Invasive Asian Fusarium — Euwallacea ambrosia beetle mutualists pose a serious threat to forests, urban landscapes and the avocado industry. Several species of the ambrosia beetle Euwallacea Coleoptera: Like all other scolytine beetles in the tribe Xyleborini, Euwallacea are thought to be obligate mutualists with their fung Ambrosia fungi in the insect-fungi symbiosis in relation to cork oak decline. Ambrosia fungi live associated with beetles Scolytidae and Platypodidae in host trees and act as a food source for the insects.

The symbiotic relation is important to the colonizing strategies of host trees by beetles. Ambrosia fungi are dimorphic: The fungi are highly specialized, adapted to a specific beetle and to the biotope where they both live. In addition other fungi have been found such as tree pathogenic fungi that may play a role in insects host colonization success. Saprophytic fungi are also present in insects galleries. This paper summarizes the importance of ambrosia fungi and the interaction with insects and hosts.

The possibility of the transport of pathogenic fungi by Platypus cylindrus to cork oak thus contributing for its decline is discussed. Full Text Available Non-native bark and ambrosia beetles represent a threat to forests worldwide. Their invasion patterns are, however, still unclear. Here we investigated first, if the spread of non-native bark and ambrosia beetles is a gradual or a discontinuous process; second, which are the main correlates of their community structure; third, whether those correlates correspond to those of native species.

We used data on species distribution of non-native and native scolytines in the continental 48 USA states. For non-native bark beetles, a discontinuous invasion process composed of long distance jumps or multiple introduction events was apparent. Species richness differences were primarily correlated with differences in import values while temperature was the main correlate of species replacement. For non-native ambrosia beetles, a more continuous invasion process was apparent, with the pool of non-native species arriving in the coastal areas that tended to be filtered as they spread to interior portions of the continental USA.

Species richness differences were mainly correlated with differences in rainfall among states, while rainfall and temperature were the main correlates of species replacement.

Our study suggests that the different ecology of bark and ambrosia beetles influences their invasion process in new environments. The lower dependency that bark beetles have.

Full Text Available The in vitro antiplasmodial activity of Ambrosia tenuifolia organic extract and its isolated sesquiterpene lactones, psilostachyin and peruvin, has been evaluated against Plasmodium falciparum F32 and W2 strains.

The cytotoxicity of both compounds was determined on lymphoid cells, and their corresponding selectivity indexes SIs were calculated. Peruvin was the most active compound on F32 strain of P. The in vitro antiplasmodial activity of Ambrosia tenuifolia organic extract and its isolated sesquiterpene lactones, psilostachyin and peruvin, has been evaluated against Plasmodium falciparum F32 and W2 strains.

Numerical ragweed pollen forecasts using different source maps: One of the key input parameters for numerical pollen forecasts is the distribution of pollen sources. Generally, three different methodologies exist to assemble such distribution maps:

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Chemical properties and NMR spectroscopic identification of certain fungal siderophores. (Aspergillus sp. ABp4, Penicillium After removal of mycelia by. The highly active extracellular siderophores previously detected in young cultures of Aspergillus nidulans and Penicillium Submit an Update/Correction/Removal. Biological removal of arsenic pollution Penicillium and Aspergillus spp. are the most metal complexation by metabolites and siderophores and methylation.

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