Imaging of polysaccharides in the tomato cell wall with Raman microspectroscopy

PubMed Central

2014-01-01

Background The primary cell wall of fruits and vegetables is a structure mainly composed of polysaccharides (pectins, hemicelluloses, cellulose). Polysaccharides are assembled into a network and linked together. It is thought that the percentage of components and of plant cell wall has an important influence on mechanical properties of fruits and vegetables. Results In this study the Raman microspectroscopy technique was introduced to the visualization of the distribution of polysaccharides in cell wall of fruit. The methodology of the sample preparation, the measurement using Raman microscope and multivariate image analysis are discussed. Single band imaging (for preliminary analysis) and multivariate image analysis methods (principal component analysis and multivariate curve resolution) were used for the identification and localization of the components in the primary cell wall. Conclusions Raman microspectroscopy supported by multivariate image analysis methods is useful in distinguishing cellulose and pectins in the cell wall in tomatoes. It presents how the localization of biopolymers was possible with minimally prepared samples. PMID:24917885

The Draft Genome of the Invasive Walking Stick, Medauroidea extradendata, Reveals Extensive Lineage-Specific Gene Family Expansions of Cell Wall Degrading Enzymes in Phasmatodea

PubMed Central

Brand, Philipp; Lin, Wei; Johnson, Brian R.

2018-01-01

Plant cell wall components are the most abundant macromolecules on Earth. The study of the breakdown of these molecules is thus a central question in biology. Surprisingly, plant cell wall breakdown by herbivores is relatively poorly understood, as nearly all early work focused on the mechanisms used by symbiotic microbes to breakdown plant cell walls in insects such as termites. Recently, however, it has been shown that many organisms make endogenous cellulases. Insects, and other arthropods, in particular have been shown to express a variety of plant cell wall degrading enzymes in many gene families with the ability to break down all the major components of the plant cell wall. Here we report the genome of a walking stick, Medauroidea extradentata, an obligate herbivore that makes uses of endogenously produced plant cell wall degrading enzymes. We present a draft of the 3.3Gbp genome along with an official gene set that contains a diversity of plant cell wall degrading enzymes. We show that at least one of the major families of plant cell wall degrading enzymes, the pectinases, have undergone a striking lineage-specific gene family expansion in the Phasmatodea. This genome will be a useful resource for comparative evolutionary studies with herbivores in many other clades and will help elucidate the mechanisms by which metazoans breakdown plant cell wall components. PMID:29588379

Distinct Cell Wall Architectures in Seed Endosperms in Representatives of the Brassicaceae and Solanaceae1[C][W][OA

PubMed Central

Lee, Kieran J.D.; Dekkers, Bas J.W.; Steinbrecher, Tina; Walsh, Cherie T.; Bacic, Antony; Bentsink, Leónie; Leubner-Metzger, Gerhard; Knox, J. Paul

2012-01-01

In some species, a crucial role has been demonstrated for the seed endosperm during germination. The endosperm has been shown to integrate environmental cues with hormonal networks that underpin dormancy and seed germination, a process that involves the action of cell wall remodeling enzymes (CWREs). Here, we examine the cell wall architectures of the endosperms of two related Brassicaceae, Arabidopsis (Arabidopsis thaliana) and the close relative Lepidium (Lepidium sativum), and that of the Solanaceous species, tobacco (Nicotiana tabacum). The Brassicaceae species have a similar cell wall architecture that is rich in pectic homogalacturonan, arabinan, and xyloglucan. Distinctive features of the tobacco endosperm that are absent in the Brassicaceae representatives are major tissue asymmetries in cell wall structural components that reflect the future site of radicle emergence and abundant heteromannan. Cell wall architecture of the micropylar endosperm of tobacco seeds has structural components similar to those seen in Arabidopsis and Lepidium endosperms. In situ and biomechanical analyses were used to study changes in endosperms during seed germination and suggest a role for mannan degradation in tobacco. In the case of the Brassicaceae representatives, the structurally homogeneous cell walls of the endosperm can be acted on by spatially regulated CWRE expression. Genetic manipulations of cell wall components present in the Arabidopsis seed endosperm demonstrate the impact of cell wall architectural changes on germination kinetics. PMID:22961130

Boron Deficiency in Trifoliate Orange Induces Changes in Pectin Composition and Architecture of Components in Root Cell Walls.

PubMed

Wu, Xiuwen; Riaz, Muhammad; Yan, Lei; Du, Chenqing; Liu, Yalin; Jiang, Cuncang

2017-01-01

Boron (B) is a micronutrient indispensable for citrus and B deficiency causes a considerable loss of productivity and quality in China. However, studies on pectin composition and architecture of cell wall components in trifoliate orange roots under B deficiency condition are not sufficient. In this study, we investigated the alteration in pectin characteristics and the architecture of cell wall components in trifoliate orange [ Poncirus trifoliata (L.) Raf.] roots under B starvation. The results showed that B-deficient roots resulted in a significant enlargement of root tips and an obvious decrease in cell wall B and uronic acid content in Na 2 CO 3 -soluble pectin compared with B-adequate roots. Meanwhile, they showed a decrease of 2-keto-3-deoxyoctanoic acid in CDTA-soluble and Na 2 CO 3 -soluble pectin in cell walls, while the degree of methylation (DM) of CDTA-soluble pectin was significantly increased under B deficiency. Transmission electron microscope (TEM) micrographs of B deficient plants showed a distinct thickening of the cell walls, with the thickness 1.82 times greater than that of control plant roots. The results from Fourier-transform infrared spectroscopy (FTIR) showed that B deficiency changed the mode of hydrogen bonding between protein and carbohydrates (cellulose and hemicellulose). The FTIR spectra exhibited a destroyed protein structure and accumulation of wax and cellulose in the cell walls under B starvation. The 13 C nuclear magnetic resonance ( 13 C-NMR) spectra showed that B starvation changed the organic carbon structure of cell walls, and enhanced the contents of amino acid, cellulose, phenols, and lignin in the cell wall. The results reveal that the swelling and weakened structural integrity of cell walls, which induced by alteration on the network of pectin and cell wall components and structure in B-deficient roots, could be a major cause of occurrence of the rapid interruption of growth and significantly enlarged root tips in trifoliate orange roots under B-insufficient condition.

The Cell Wall-Associated Proteins in the Dimorphic Pathogenic Species of Paracoccidioides.

PubMed

Puccia, Rosana; Vallejo, Milene C; Longo, Larissa V G

2017-01-01

Paracoccidioides brasiliensis and P. lutzii cause human paracoccidioidomycosis (PCM). They are dimorphic ascomycetes that grow as filaments at mild temperatures up to 28oC and as multibudding pathogenic yeast cells at 37oC. Components of the fungal cell wall have an important role in the interaction with the host because they compose the cell outermost layer. The Paracoccidioides cell wall is composed mainly of polysaccharides, but it also contains proportionally smaller rates of proteins, lipids, and melanin. The polysaccharide cell wall composition and structure of Paracoccidioides yeast cells, filamentous and transition phases were studied in detail in the past. Other cell wall components have been better analyzed in the last decades. The present work gives to the readers a detailed updated view of cell wall-associated proteins. Proteins that have been localized at the cell wall compartment using antibodies are individually addressed. We also make an overview about PCM, the Paracoccidioides cell wall structure, secretion mechanisms, and fungal extracellular vesicles. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Requirement of the CroRS Two-Component System for Resistance to Cell Wall-Targeting Antimicrobials in Enterococcus faecium.

PubMed

Kellogg, Stephanie L; Little, Jaime L; Hoff, Jessica S; Kristich, Christopher J

2017-05-01

Enterococci are serious opportunistic pathogens that are resistant to many cell wall-targeting antibiotics. The CroRS two-component signaling system responds to antibiotic-mediated cell wall stress and is critical for resistance to cell wall-targeting antibiotics in Enterococcus faecalis Here, we identify and characterize an orthologous two-component system found in Enterococcus faecium that is functionally equivalent to the CroRS system of E. faecalis Deletion of croRS in E. faecium resulted in marked susceptibility to cell wall-targeting agents including cephalosporins and bacitracin, as well as moderate susceptibility to ampicillin and vancomycin. As in E. faecalis , exposure to bacitracin and vancomycin stimulates signaling through the CroRS system in E. faecium Moreover, the CroRS system is critical in E. faecium for enhanced beta-lactam resistance mediated by overexpression of Pbp5. Expression of a Pbp5 variant that confers enhanced beta-lactam resistance cannot overcome the requirement for CroRS function. Thus, the CroRS system is a conserved signaling system that responds to cell wall stress to promote intrinsic resistance to important cell wall-targeting antibiotics in clinically relevant enterococci. Copyright © 2017 American Society for Microbiology.

Requirement of the CroRS Two-Component System for Resistance to Cell Wall-Targeting Antimicrobials in Enterococcus faecium

PubMed Central

Kellogg, Stephanie L.; Little, Jaime L.; Hoff, Jessica S.

2017-01-01

ABSTRACT Enterococci are serious opportunistic pathogens that are resistant to many cell wall-targeting antibiotics. The CroRS two-component signaling system responds to antibiotic-mediated cell wall stress and is critical for resistance to cell wall-targeting antibiotics in Enterococcus faecalis. Here, we identify and characterize an orthologous two-component system found in Enterococcus faecium that is functionally equivalent to the CroRS system of E. faecalis. Deletion of croRS in E. faecium resulted in marked susceptibility to cell wall-targeting agents including cephalosporins and bacitracin, as well as moderate susceptibility to ampicillin and vancomycin. As in E. faecalis, exposure to bacitracin and vancomycin stimulates signaling through the CroRS system in E. faecium. Moreover, the CroRS system is critical in E. faecium for enhanced beta-lactam resistance mediated by overexpression of Pbp5. Expression of a Pbp5 variant that confers enhanced beta-lactam resistance cannot overcome the requirement for CroRS function. Thus, the CroRS system is a conserved signaling system that responds to cell wall stress to promote intrinsic resistance to important cell wall-targeting antibiotics in clinically relevant enterococci. PMID:28223383

Phenolic components of the primary cell wall. Feruloylated disaccharides of D-galactose and L-arabinose from spinach polysaccharide.

PubMed Central

Fry, S C

1982-01-01

1. Cell walls from rapidly growing cell suspension cultures of Spinacia oleracea L. contained ferulic acid and p-coumaric acid esterified with a water-insoluble polymer. 2. Prolonged treatment with trypsin did not release may feruloyl esters from dearabinofuranosylated cell walls, and the polymer was also insoluble in phenol/acetic acid/water (2:1:1, w/v/v). 3. Treatment of the cell walls with the fungal hydrolase preparation "Driselase' did liberate low-Mr feruloyl esters. The major esters were 4-O-(6-O-feruloyl-beta-D-galactopyranosyl)-D-galactose and 3?-O-feruloyl-alpha-L-arabinopyranosyl)-L-arabinose. These two esters accounted for about 60% of the cell-wall ferulate. 4. It is concluded that the feruloylation of cell-wall polymers is not a random process, but occurs at very specific sites, probably on the arabinogalactan component of pectin. 5. The possible role of such phenolic substituents in cell-wall architecture and growth is discussed. PMID:7115300

Structural Studies of Complex Carbohydrates of Plant Cell Walls

DOE Office of Scientific and Technical Information (OSTI.GOV)

Darvill, Alan; Hahn, Michael G.; O'Neill, Malcolm A.

Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell wallsmore » and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.« less

Sticking to cellulose: exploiting Arabidopsis seed coat mucilage to understand cellulose biosynthesis and cell wall polysaccharide interactions.

PubMed

Griffiths, Jonathan S; North, Helen M

2017-05-01

The cell wall defines the shape of cells and ultimately plant architecture. It provides mechanical resistance to osmotic pressure while still being malleable and allowing cells to grow and divide. These properties are determined by the different components of the wall and the interactions between them. The major components of the cell wall are the polysaccharides cellulose, hemicellulose and pectin. Cellulose biosynthesis has been extensively studied in Arabidopsis hypocotyls, and more recently in the mucilage-producing epidermal cells of the seed coat. The latter has emerged as an excellent system to study cellulose biosynthesis and the interactions between cellulose and other cell wall polymers. Here we review some of the major advances in our understanding of cellulose biosynthesis in the seed coat, and how mucilage has aided our understanding of the interactions between cellulose and other cell wall components required for wall cohesion. Recently, 10 genes involved in cellulose or hemicellulose biosynthesis in mucilage have been identified. These discoveries have helped to demonstrate that xylan side-chains on rhamnogalacturonan I act to link this pectin directly to cellulose. We also examine other factors that, either directly or indirectly, influence cellulose organization or crystallization in mucilage. © 2017 INRA. New Phytologist © 2017 New Phytologist Trust.

16. Interior view of Test Cell 8 (oxidizer) in Components ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. Interior view of Test Cell 8 (oxidizer) in Components Test Laboratory (T-27), showing east wall. Photograph shows upgraded instrumentation, piping, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. The windows in the wall enable personnel in the control room to observe component testing in the cell. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

A study of the native cell wall structures of the marine alga Ventricaria ventricosa (Siphonocladales, Chlorophyceae) using atomic force microscopy.

PubMed

Eslick, Enid M; Beilby, Mary J; Moon, Anthony R

2014-04-01

A substantial proportion of the architecture of the plant cell wall remains unknown with a few cell wall models being proposed. Moreover, even less is known about the green algal cell wall. Techniques that allow direct visualization of the cell wall in as near to its native state are of importance in unravelling the spatial arrangement of cell wall structures and hence in the development of cell wall models. Atomic force microscopy (AFM) was used to image the native cell wall of living cells of Ventricaria ventricosa (V. ventricosa) at high resolution under physiological conditions. The cell wall polymers were identified mainly qualitatively via their structural appearance. The cellulose microfibrils (CMFs) were easily recognizable and the imaging results indicate that the V. ventricosa cell wall has a cross-fibrillar structure throughout. We found the native wall to be abundant in matrix polysaccharides existing in different curing states. The soft phase matrix polysaccharides susceptible by the AFM scanning tip existed as a glutinous fibrillar meshwork, possibly incorporating both the pectic- and hemicellulosic-type substances. The hard phase matrix producing clearer images, revealed coiled fibrillar structures associated with CMFs, sometimes being resolved as globular structures by the AFM tip. The coiling fibrillar structures were also seen in the images of isolated cell wall fragments. The mucilaginous component of the wall was discernible from the gelatinous cell wall matrix as it formed microstructural domains over the surface. AFM has been successful in imaging the native cell wall and revealing novel findings such as the 'coiling fibrillar structures' and cell wall components which have previously not been seen, that is, the gelatinous matrix phase.

Forage digestibility: the intersection of cell wall lignification and plant tissue anatomy

USDA-ARS?s Scientific Manuscript database

Cellulose and the other polysaccharides present in forage cell walls can be completely degraded by the rumen microflora but only when these polysaccharides have been isolated from the wall and all matrix structures eliminated. Understanding how cell wall component interactions limit microbial degrad...

The role of the cell wall in fungal pathogenesis

PubMed Central

Arana, David M.; Prieto, Daniel; Román, Elvira; Nombela, César; Alonso‐Monge, Rebeca; Pla, Jesús

2009-01-01

Summary Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections. PMID:21261926

Targeted self-assembly of functionalized carbon nanotubes on tumors

DOEpatents

Scheinberg, David A.; McDevitt, Michael R.; Villa, Carlos H.; Mulvey, J. Justin

2018-05-22

Provided herein are methods for delivering a molecule in situ to a cell and for treating a cancer via the in situ delivery. The methods comprise contacting or administering to the cell, as two separate components, a morpholino oligonucleotide comprising a targeting moiety followed by a single wall nanotube construct comprising second morpholino oligonucleotides complementary to the first morpholino oligonucleotides and one or both of a therapeutic or diagnostic payload molecule linked to the single wall nanotube construct. Upon self-assembly of a single wall nanotube complex via hybridization of the first morpholino and second complementary morpholino oligonucleotides at the cell, the payload molecule is delivered. Also provided is the two component self-assembly single wall nanotube system and the single wall nanotube construct comprising the second component.

A model of cell wall expansion based on thermodynamics of polymer networks

NASA Technical Reports Server (NTRS)

Veytsman, B. A.; Cosgrove, D. J.

1998-01-01

A theory of cell wall extension is proposed. It is shown that macroscopic properties of cell walls can be explained through the microscopic properties of interpenetrating networks of cellulose and hemicellulose. The qualitative conclusions of the theory agree with the existing experimental data. The dependence of the cell wall yield threshold on the secretion of the wall components is discussed.

13. Interior view of Test Cell 9 (fuel) in Components ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Interior view of Test Cell 9 (fuel) in Components Test Laboratory (T-27), showing west and north walls. Photograph shows upgraded instrumentation, piping, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. Two windows in the wall to the left enable personnel in the control room to observe component testing in the cell. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

15. Interior view of Test Cell 10 (environmental) in Components ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. Interior view of Test Cell 10 (environmental) in Components Test Laboratory (T-27), showing north and east walls. Photograph shows upgraded instrumentation, piping, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. The window in the wall to the left enables personnel in the control room to observe component testing in the cell. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Genetic and Quantitative Trait Locus Analysis of Cell Wall Components and Forage Digestibility in the Zheng58 × HD568 Maize RIL Population at Anthesis Stage

PubMed Central

Li, Kun; Wang, Hongwu; Hu, Xiaojiao; Ma, Feiqian; Wu, Yujin; Wang, Qi; Liu, Zhifang; Huang, Changling

2017-01-01

The plant cell wall plays vital roles in various aspects of the plant life cycle. It provides a basic structure for cells and gives mechanical rigidity to the whole plant. Some complex cell wall components are involved in signal transduction during pathogenic infection and pest infestations. Moreover, the lignification level of cell walls strongly influences the digestibility of forage plants. To determine the genetic bases of cell wall components and digestibility, quantitative trait locus (QTL) analyses for six related traits were performed using a recombinant inbred line (RIL) population from a cross between Zheng58 and HD568. Eight QTL for in vitro neutral detergent fiber (NDF) digestibility were observed, out of which only two increasing alleles came from HD568. Three QTL out of ten with alleles increasing in vitro dry matter digestibility also originated from HD568. Five–ten QTL were detected for lignin, cellulose content, acid detergent fiber, and NDF content. Among these results, 29.8% (14/47) of QTL explained >10% of the phenotypic variation in the RIL population, whereas 70.2% (33/47) explained ≤10%. These results revealed that in maize stalks, a few large-effect QTL and a number of minor-effect QTL contributed to most of the genetic components involved in cell wall biosynthesis and digestibility. PMID:28883827

Genetic and Quantitative Trait Locus Analysis of Cell Wall Components and Forage Digestibility in the Zheng58 × HD568 Maize RIL Population at Anthesis Stage.

PubMed

Li, Kun; Wang, Hongwu; Hu, Xiaojiao; Ma, Feiqian; Wu, Yujin; Wang, Qi; Liu, Zhifang; Huang, Changling

2017-01-01

The plant cell wall plays vital roles in various aspects of the plant life cycle. It provides a basic structure for cells and gives mechanical rigidity to the whole plant. Some complex cell wall components are involved in signal transduction during pathogenic infection and pest infestations. Moreover, the lignification level of cell walls strongly influences the digestibility of forage plants. To determine the genetic bases of cell wall components and digestibility, quantitative trait locus (QTL) analyses for six related traits were performed using a recombinant inbred line (RIL) population from a cross between Zheng58 and HD568. Eight QTL for in vitro neutral detergent fiber (NDF) digestibility were observed, out of which only two increasing alleles came from HD568. Three QTL out of ten with alleles increasing in vitro dry matter digestibility also originated from HD568. Five-ten QTL were detected for lignin, cellulose content, acid detergent fiber, and NDF content. Among these results, 29.8% (14/47) of QTL explained >10% of the phenotypic variation in the RIL population, whereas 70.2% (33/47) explained ≤10%. These results revealed that in maize stalks, a few large-effect QTL and a number of minor-effect QTL contributed to most of the genetic components involved in cell wall biosynthesis and digestibility.

Cellulose and pectin localization in roots of mycorrhizalAllium porrum: labelling continuity between host cell wall and interfacial material.

PubMed

Bonfante-Fasolo, P; Vian, B; Perotto, S; Faccio, A; Knox, J P

1990-03-01

Two different types of contacts (or interfaces) exist between the plant host and the fungus during the vesicular-arbuscular mycorrhizal symbiosis, depending on whether the fungus is intercellular or intracellular. In the first case, the walls of the partners are in contact, while in the second case the fungal wall is separated from the host cytoplasm by the invaginated host plasmamembrane and by an interfacial material. In order to verify the origin of the interfacial material, affinity techniques which allow identification in situ of cell-wall components, were used. Cellobiohydrolase (CBH I) that binds to cellulose and a monoclonal antibody (JIM 5) that reacts with pectic components were tested on roots ofAllium porrum L. (leek) colonized byGlomus versiforme (Karst.) Berch. Both probes gave a labelling specific for the host cell wall, but each probe labelled over specific and distinct areas. The CBH I-colloidal gold complex heavily labelled the thick epidermal cell walls, whereas JIM 5 only labelled this area weakly. Labelling of the hypodermis was mostly on intercellular material after treatment with JIM 5 and only on the wall when CBH I was used. Suberin bands found on the radial walls were never labelled. Cortical cells were mostly labelled on the middle lamella with JIM 5 and on the wall with CBH I. Gold granules from the two probes were found in interfacial material both near the point where the fungus enters the cell and around the thin hyphae penetrating deep into the cell. The ultrastructural observations demonstrate that cellulose and pectic components have different but complementary distributions in the walls of root cells involved in the mycorrhizal symbiosis. These components show a similar distribution in the interfacial material laid down around the vesicular-arbuscular mycorrhizal fungus indicating that the interfacial material is of host origin.

A rapid live-cell ELISA for characterizing antibodies against cell surface antigens of Chlamydomonas reinhardtii and its use in isolating algae from natural environments with related cell wall components.

PubMed

Jiang, Wenzhi; Cossey, Sarah; Rosenberg, Julian N; Oyler, George A; Olson, Bradley J S C; Weeks, Donald P

2014-09-25

Cell walls are essential for most bacteria, archaea, fungi, algae and land plants to provide shape, structural integrity and protection from numerous biotic and abiotic environmental factors. In the case of eukaryotic algae, relatively little is known of the composition, structure or mechanisms of assembly of cell walls in individual species or between species and how these differences enable algae to inhabit a great diversity of environments. In this paper we describe the use of camelid antibody fragments (VHHs) and a streamlined ELISA assay as powerful new tools for obtaining mono-specific reagents for detecting individual algal cell wall components and for isolating algae that share a particular cell surface component. To develop new microalgal bioprospecting tools to aid in the search of environmental samples for algae that share similar cell wall and cell surface components, we have produced single-chain camelid antibodies raised against cell surface components of the single-cell alga, Chlamydomonas reinhardtii. We have cloned the variable-region domains (VHHs) from the camelid heavy-chain-only antibodies and overproduced tagged versions of these monoclonal-like antibodies in E. coli. Using these VHHs, we have developed an accurate, facile, low cost ELISA that uses live cells as a source of antigens in their native conformation and that requires less than 90 minutes to perform. This ELISA technique was demonstrated to be as accurate as standard ELISAs that employ proteins from cell lysates and that generally require >24 hours to complete. Among the cloned VHHs, VHH B11, exhibited the highest affinity (EC50 < 1 nM) for the C. reinhardtii cell surface. The live-cell ELISA procedure was employed to detect algae sharing cell surface components with C. reinhardtii in water samples from natural environments. In addition, mCherry-tagged VHH B11 was used along with fluorescence activated cell sorting (FACS) to select individual axenic isolates of presumed wild relatives of C. reinhardtii and other Chlorphyceae from the same environmental samples. Camelid antibody VHH domains provide a highly specific tool for detection of individual cell wall components of algae and for allowing the selection of algae that share a particular cell surface molecule from diverse ecosystems.

Impact of Cell Wall Composition on Maize Resistance to Pests and Diseases

PubMed Central

Santiago, Rogelio; Barros-Rios, Jaime; Malvar, Rosa A.

2013-01-01

In cereals, the primary cell wall is built of a skeleton of cellulosic microfibrils embedded in a matrix of hemicelluloses and smaller amounts of pectins, glycoproteins and hydroxycinnamates. Later, during secondary wall development, p-coumaryl, coniferyl and sinapyl alcohols are copolymerized to form mixed lignins. Several of these cell wall components show a determinative role in maize resistance to pest and diseases. However, defense mechanisms are very complex and vary among the same plant species, different tissues or even the same tissue at different developmental stages. Thus, it is important to highlight that the role of the cell wall components needs to be tested in diverse genotypes and specific tissues where the feeding or attacking by the pathogen takes place. Understanding the role of cell wall constituents as defense mechanisms may allow modifications of crops to withstand pests and diseases. PMID:23535334

Cell wall α-1,3-glucan prevents α-amylase adsorption onto fungal cell in submerged culture of Aspergillus oryzae.

PubMed

Zhang, Silai; Sato, Hiroki; Ichinose, Sakurako; Tanaka, Mizuki; Miyazawa, Ken; Yoshimi, Akira; Abe, Keietsu; Shintani, Takahiro; Gomi, Katsuya

2017-07-01

We have previously reported that α-amylase (Taka-amylase A, TAA) activity disappears in the later stage of submerged Aspergillus oryzae culture as a result of TAA adsorption onto the cell wall. Chitin, one of the major components of the cell wall, was identified as a potential factor that facilitates TAA adsorption. However, TAA adsorption only occurred in the later stage of cultivation, although chitin was assumed to be sufficiently abundant in the cell wall regardless of the submerged culture period. This suggested the presence a factor that inhibits TAA adsorption to the cell wall in the early stage of cultivation. In the current study, we identified α-1,3-glucan as a potential inhibiting factor for TAA adsorption. We constructed single, double, and triple disruption mutants of three α-1,3-glucan synthase genes (agsA, agsB, and agsC) in A. oryzae. Growth characteristics and cell wall component analysis of these disruption strains showed that AgsB plays a major role in α-1,3-glucan synthesis. In the ΔagsB mutant, TAA was adsorbed onto the mycelium in all stages of cultivation (early and later), and the ΔagsB mutant cell walls had a significantly high capacity for TAA adsorption. Moreover, the α-1,3-glucan content of the cell wall prepared from the wild-type strain in the later stage of cultivation was markedly reduced compared with that in the early stage. These results suggest that α-1,3-glucan is a potential inhibiting factor for TAA adsorption onto the cell wall component, chitin, in the early stage of submerged culture in A. oryzae. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

High-resolution solution-state NMR of unfractionated plant cell walls

Treesearch

John Ralph; Fachuang Lu; Hoon Kim; Dino Ress; Daniel J. Yelle; Kenneth E. Hammel; Sally A. Ralph; Bernadette Nanayakkara; Armin Wagner; Takuya Akiyama; Paul F. Schatz; Shawn D. Mansfield; Noritsugu Terashima; Wout Boerjan; Bjorn Sundberg; Mattias Hedenstrom

2009-01-01

Detailed structural studies on the plant cell wall have traditionally been difficult. NMR is one of the preeminent structural tools, but obtaining high-resolution solution-state spectra has typically required fractionation and isolation of components of interest. With recent methods for dissolution of, admittedly, finely divided plant cell wall material, the wall can...

Post-Synthetic Defucosylation of AGP by Aspergillus nidulans α-1,2-Fucosidase Expressed in Arabidopsis Apoplast Induces Compensatory Upregulation of α-1,2-Fucosyltransferases.

PubMed

Pogorelko, Gennady V; Reem, Nathan T; Young, Zachary T; Chambers, Lauran; Zabotina, Olga A

2016-01-01

Cell walls are essential components of plant cells which perform a variety of important functions for the different cell types, tissues and organs of a plant. Besides mechanical function providing cell shape, cell walls participate in intercellular communication, defense during plant-microbe interactions, and plant growth. The plant cell wall consists predominantly of polysaccharides with the addition of structural glycoproteins, phenolic esters, minerals, lignin, and associated enzymes. Alterations in the cell wall composition created through either changes in biosynthesis of specific constituents or their post-synthetic modifications in the apoplast compromise cell wall integrity and frequently induce plant compensatory responses as a result of these alterations. Here we report that post-synthetic removal of fucose residues specifically from arabinogalactan proteins in the Arabidopsis plant cell wall induces differential expression of fucosyltransferases and leads to the root and hypocotyl elongation changes. These results demonstrate that the post-synthetic modification of cell wall components presents a valuable approach to investigate the potential signaling pathways induced during plant responses to such modifications that usually occur during plant development and stress responses.

Cell walls of the dimorphic fungal pathogens Sporothrix schenckii and Sporothrix brasiliensis exhibit bilaminate structures and sloughing of extensive and intact layers

PubMed Central

Walker, Louise A.; Niño-Vega, Gustavo; Mora-Montes, Héctor M.; Neves, Gabriela W. P.; Villalobos-Duno, Hector; Barreto, Laura; Garcia, Karina; Franco, Bernardo; Martínez-Álvarez, José A.; Munro, Carol A.; Gow, Neil A. R.

2018-01-01

Sporotrichosis is a subcutaneous mycosis caused by pathogenic species of the Sporothrix genus. A new emerging species, Sporothrix brasiliensis, is related to cat-transmitted sporotrichosis and has severe clinical manifestations. The cell wall of pathogenic fungi is a unique structure and impacts directly on the host immune response. We reveal and compare the cell wall structures of Sporothrix schenckii and S. brasiliensis using high-pressure freezing electron microscopy to study the cell wall organization of both species. To analyze the components of the cell wall, we also used infrared and 13C and 1H NMR spectroscopy and the sugar composition was determined by quantitative high-performance anion-exchange chromatography. Our ultrastructural data revealed a bi-layered cell wall structure for both species, including an external microfibrillar layer and an inner electron-dense layer. The inner and outer layers of the S. brasiliensis cell wall were thicker than those of S. schenckii, correlating with an increase in the chitin and rhamnose contents. Moreover, the outer microfibrillar layer of the S. brasiliensis cell wall had longer microfibrils interconnecting yeast cells. Distinct from those of other dimorphic fungi, the cell wall of Sporothrix spp. lacked α-glucan component. Interestingly, glycogen α-particles were identified in the cytoplasm close to the cell wall and the plasma membrane. The cell wall structure as well as the presence of glycogen α-particles varied over time during cell culture. The structural differences observed in the cell wall of these Sporothrix species seemed to impact its uptake by monocyte-derived human macrophages. The data presented here show a unique cell wall structure of S. brasiliensis and S. schenckii during the yeast parasitic phase. A new cell wall model for Sporothrix spp. is therefore proposed that suggests that these fungi molt sheets of intact cell wall layers. This observation may have significant effects on localized and disseminated immunopathology. PMID:29522522

Molecular basis of cell integrity and morphogenesis in Saccharomyces cerevisiae.

PubMed Central

Cid, V J; Durán, A; del Rey, F; Snyder, M P; Nombela, C; Sánchez, M

1995-01-01

In fungi and many other organisms, a thick outer cell wall is responsible for determining the shape of the cell and for maintaining its integrity. The budding yeast Saccharomyces cerevisiae has been a useful model organism for the study of cell wall synthesis, and over the past few decades, many aspects of the composition, structure, and enzymology of the cell wall have been elucidated. The cell wall of budding yeasts is a complex and dynamic structure; its arrangement alters as the cell grows, and its composition changes in response to different environmental conditions and at different times during the yeast life cycle. In the past few years, we have witnessed a profilic genetic and molecular characterization of some key aspects of cell wall polymer synthesis and hydrolysis in the budding yeast. Furthermore, this organism has been the target of numerous recent studies on the topic of morphogenesis, which have had an enormous impact on our understanding of the intracellular events that participate in directed cell wall synthesis. A number of components that direct polarized secretion, including those involved in assembly and organization of the actin cytoskeleton, secretory pathways, and a series of novel signal transduction systems and regulatory components have been identified. Analysis of these different components has suggested pathways by which polarized secretion is directed and controlled. Our aim is to offer an overall view of the current understanding of cell wall dynamics and of the complex network that controls polarized growth at particular stages of the budding yeast cell cycle and life cycle. PMID:7565410

Peroxidase activity in cotton cell culture infected with Verticillium dahliae

USDA-ARS?s Scientific Manuscript database

In our studies with cotton, we have shown that the plant’s induced anionic peroxidases bind to chitin, which is a component of the cell wall of the plant pathogenic fungus Verticillium dahliae. In binding to the cell wall surface, they disrupt the integrity of the pathogen’s cell wall. Thus, these...

Genome-Wide Association Study Reveals the Genetic Basis of Stalk Cell Wall Components in Maize

PubMed Central

Hu, Xiaojiao; Liu, Zhifang; Wu, Yujin; Huang, Changling

2016-01-01

Lignin, cellulose and hemicellulose are the three main components of the plant cell wall and can impact stalk quality by affecting cell wall structure and strength. In this study, we evaluated the lignin (LIG), cellulose (CEL) and hemicellulose (HC) contents in maize using an association mapping panel that included 368 inbred lines in seven environments. A genome-wide association study using approximately 0.56 million SNPs with a minor allele frequency of 0.05 identified 22, 18 and 24 loci significantly associated with LIG, CEL and HC at P < 1.0×10−4, respectively. The allelic variation of each significant association contributed 4 to 7% of the phenotypic variation. Candidate genes identified by GWAS mainly encode enzymes involved in cell wall metabolism, transcription factors, protein kinase and protein related to other biological processes. Among the association signals, six candidate genes had pleiotropic effects on lignin and cellulose content. These results provide valuable information for better understanding the genetic basis of stalk cell wall components in maize. PMID:27479588

In-situ Raman microprobe studies of plant cell walls: macromolecular organization and compositional variability in the secondary wall of Picea mariana (Mill.) B.S.P.

Treesearch

U.P. Agarwal; R.H. Atalla

1986-01-01

Native-state organization and distribution of cell-wall components in the secondary wall of woody tissue from P. mariana (Black Spruce) have been investigated using polarized Raman microspectroscopy. Evidence for orientation is detected through Raman intensity variations resulting from rotations of the exciting electric vector with respect to cell-wall geometry....

Cotton fiber tips have diverse morphologies and show evidence of apical cell wall synthesis

PubMed Central

Stiff , Michael R.; Haigler, Candace H.

2016-01-01

Cotton fibers arise through highly anisotropic expansion of a single seed epidermal cell. We obtained evidence that apical cell wall synthesis occurs through examining the tips of young elongating Gossypium hirsutum (Gh) and G. barbadense (Gb) fibers. We characterized two tip types in Gh fiber (hemisphere and tapered), each with distinct apical diameter, central vacuole location, and distribution of cell wall components. The apex of Gh hemisphere tips was enriched in homogalacturonan epitopes, including a relatively high methyl-esterified form associated with cell wall pliability. Other wall components increased behind the apex including cellulose and the α-Fuc-(1,2)-β-Gal epitope predominantly found in xyloglucan. Gb fibers had only one narrow tip type featuring characters found in each Gh tip type. Pulse-labeling of cell wall glucans indicated wall synthesis at the apex of both Gh tip types and in distal zones. Living Gh hemisphere and Gb tips ruptured preferentially at the apex upon treatment with wall degrading enzymes, consistent with newly synthesized wall at the apex. Gh tapered tips ruptured either at the apex or distantly. Overall, the results reveal diverse cotton fiber tip morphologies and support primary wall synthesis occurring at the apex and discrete distal regions of the tip. PMID:27301434

Organ and Tissue-Specific Localisation of Selected Cell Wall Epitopes in the Zygotic Embryo of Brachypodium distachyon.

PubMed

Betekhtin, Alexander; Milewska-Hendel, Anna; Lusinska, Joanna; Chajec, Lukasz; Kurczynska, Ewa; Hasterok, Robert

2018-03-03

The plant cell wall shows a great diversity regarding its chemical composition, which may vary significantly even during different developmental stages. In this study, we analysed the distribution of several cell wall epitopes in embryos of Brachypodium distachyon (Brachypodium). We also described the variations in the nucleus shape and the number of nucleoli that occurred in some embryo cells. The use of transmission electron microscopy, and histological and immunolocalisation techniques permitted the distribution of selected arabinogalactan proteins, extensins, pectins, and hemicelluloses on the embryo surface, internal cell compartments, and in the context of the cell wall ultrastructure to be demonstrated. We revealed that the majority of arabinogalactan proteins and extensins were distributed on the cell surface and that pectins were the main component of the seed coat and other parts, such as the mesocotyl cell walls and the radicula. Hemicelluloses were localised in the cell wall and outside of the radicula protodermis, respectively. The specific arrangement of those components may indicate their significance during embryo development and seed germination, thus suggesting the importance of their protective functions. Despite the differences in the cell wall composition, we found that some of the antibodies can be used as markers to identify specific cells and the parts of the developing Brachypodium embryo.

An unusual xylan in Arabidopsis primary cell walls is synthesised by GUX3, IRX9L, IRX10L and IRX14

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mortimer, Jenny C.; Faria-Blanc, Nuno; Yu, Xiaolan

Xylan is a crucial component of many plant primary and secondary cell walls. However, the structure and function of xylan in the dicotyledon primary cell wall is not well understood. Here, we characterized a xylan that is specific to tissues enriched in Arabidopsis primary cell walls. Unlike previously described xylans, this xylan carries a pentose linked 1–2 to the α-1,2-d-glucuronic acid (GlcA) side chains on the β-1,4-Xyl backbone. The frequent and precisely regular spacing of GlcA substitutions every six xylosyl residues along the backbone is also unlike that previously observed in secondary cell wall xylan. Molecular genetics, in vitro assays,more » and expression data suggest that IRX9L, IRX10L and IRX14 are required for xylan backbone synthesis in primary cell wall synthesising tissues. IRX9 and IRX10 are not involved in the primary cell wall xylan synthesis but are functionally exchangeable with IRX9L and IRX10L. GUX3 is the only glucuronyltransferase required for the addition of the GlcA decorations on the xylan. Lastly, the differences in xylan structure in primary versus secondary cell walls might reflect the different roles in cross-linking and interaction with other cell wall components.« less

An unusual xylan in Arabidopsis primary cell walls is synthesised by GUX3, IRX9L, IRX10L and IRX14

DOE PAGES

Mortimer, Jenny C.; Faria-Blanc, Nuno; Yu, Xiaolan; ...

2015-06-04

Xylan is a crucial component of many plant primary and secondary cell walls. However, the structure and function of xylan in the dicotyledon primary cell wall is not well understood. Here, we characterized a xylan that is specific to tissues enriched in Arabidopsis primary cell walls. Unlike previously described xylans, this xylan carries a pentose linked 1–2 to the α-1,2-d-glucuronic acid (GlcA) side chains on the β-1,4-Xyl backbone. The frequent and precisely regular spacing of GlcA substitutions every six xylosyl residues along the backbone is also unlike that previously observed in secondary cell wall xylan. Molecular genetics, in vitro assays,more » and expression data suggest that IRX9L, IRX10L and IRX14 are required for xylan backbone synthesis in primary cell wall synthesising tissues. IRX9 and IRX10 are not involved in the primary cell wall xylan synthesis but are functionally exchangeable with IRX9L and IRX10L. GUX3 is the only glucuronyltransferase required for the addition of the GlcA decorations on the xylan. Lastly, the differences in xylan structure in primary versus secondary cell walls might reflect the different roles in cross-linking and interaction with other cell wall components.« less

If walls could talk

NASA Technical Reports Server (NTRS)

Braam, J.; McIntire, L. V. (Principal Investigator)

1999-01-01

The plant cell wall is very complex, both in structure and function. The wall components and the mechanical properties of the wall have been implicated in conveying information that is important for morphogenesis. Proteoglycans, fragments of polysaccharides and the structural integrity of the wall may relay signals that influence cellular differentiation and growth control. Furthering our knowledge of cell wall structure and function is likely to have a profound impact on our understanding of how plant cells communicate with the extracellular environment.

Label-free Chemical Imaging of Fungal Spore Walls by Raman Microscopy and Multivariate Curve Resolution Analysis

PubMed Central

Noothalapati, Hemanth; Sasaki, Takahiro; Kaino, Tomohiro; Kawamukai, Makoto; Ando, Masahiro; Hamaguchi, Hiro-o; Yamamoto, Tatsuyuki

2016-01-01

Fungal cell walls are medically important since they represent a drug target site for antifungal medication. So far there is no method to directly visualize structurally similar cell wall components such as α-glucan, β-glucan and mannan with high specificity, especially in a label-free manner. In this study, we have developed a Raman spectroscopy based molecular imaging method and combined multivariate curve resolution analysis to enable detection and visualization of multiple polysaccharide components simultaneously at the single cell level. Our results show that vegetative cell and ascus walls are made up of both α- and β-glucans while spore wall is exclusively made of α-glucan. Co-localization studies reveal the absence of mannans in ascus wall but are distributed primarily in spores. Such detailed picture is believed to further enhance our understanding of the dynamic spore wall architecture, eventually leading to advancements in drug discovery and development in the near future. PMID:27278218

β-1,3-Glucans are components of brown seaweed (Phaeophyceae) cell walls.

PubMed

Raimundo, Sandra Cristina; Pattathil, Sivakumar; Eberhard, Stefan; Hahn, Michael G; Popper, Zoë A

2017-03-01

LAMP is a cell wall-directed monoclonal antibody (mAb) that recognizes a β-(1,3)-glucan epitope. It has primarily been used in the immunolocalization of callose in vascular plant cell wall research. It was generated against a brown seaweed storage polysaccharide, laminarin, although it has not often been applied in algal research. We conducted in vitro (glycome profiling of cell wall extracts) and in situ (immunolabeling of sections) studies on the brown seaweeds Fucus vesiculosus (Fucales) and Laminaria digitata (Laminariales). Although glycome profiling did not give a positive signal with the LAMP mAb, this antibody clearly detected the presence of the β-(1,3)-glucan in situ, showing that this epitope is a constituent of these brown algal cell walls. In F. vesiculosus, the β-(1,3)-glucan epitope was present throughout the cell walls in all thallus parts; in L. digitata, the epitope was restricted to the sieve plates of the conductive elements. The sieve plate walls also stained with aniline blue, a fluorochrome used as a probe for callose. Enzymatic digestion with an endo-β-(1,3)-glucanase removed the ability of the LAMP mAb to label the cell walls. Thus, β-(1,3)-glucans are structural polysaccharides of F. vesiculosus cell walls and are integral components of the sieve plates in these brown seaweeds, reminiscent of plant callose.

Cell Wall Ultrastructure of Stem Wood, Roots, and Needles of a Conifer Varies in Response to Moisture Availability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pattathil, Sivakumar; Ingwers, Miles W.; Victoriano, Olivia L.

The composition, integrity, and architecture of the macromolecular matrix of cell walls, collectively referred to as cell wall ultrastructure, exhibits variation across species and organs and among cell types within organs. Indirect approaches have suggested that modifications to cell wall ultrastructure occur in response to abiotic stress; however, modifications have not been directly observed. Glycome profiling was used to study cell wall ultrastructure by examining variation in composition and extractability of non-cellulosic glycans in cell walls of stem wood, roots, and needles of loblolly pine saplings exposed to high and low soil moisture. Soil moisture influenced physiological processes and themore » overall composition and extractability of cell wall components differed as a function of soil moisture treatments. The strongest response of cell wall ultrastructure to soil moisture was increased extractability of pectic backbone epitopes in the low soil moisture treatment. The higher abundance of these pectic backbone epitopes in the oxalate extract indicate that the loosening of cell wall pectic components could be associated with the release of pectic signals as a stress response. The increased extractability of pectic backbone epitopes in response to low soil moisture availability was more pronounced in stem wood than in roots or needles. Additional responses to low soil moisture availability were observed in lignin associated carbohydrates released in chlorite extracts of stem wood, including an increased abundance of pectic arabinogalactan epitopes. Overall, these results indicate that cell walls of loblolly pine organs undergo changes in their ultrastructural composition and extractability as a response to soil moisture availability and that cell walls of the stem wood are more responsive to low soil moisture availability compared to cell walls of roots and needles. In conclusion, to our knowledge, this is the first direct evidence, delineated by glycomic analyses, that abiotic stress affects cell wall ultrastructure. This study is also unique in that glycome profiling of pine needles has never before been reported.« less

Cell Wall Ultrastructure of Stem Wood, Roots, and Needles of a Conifer Varies in Response to Moisture Availability.

PubMed

Pattathil, Sivakumar; Ingwers, Miles W; Victoriano, Olivia L; Kandemkavil, Sindhu; McGuire, Mary Anne; Teskey, Robert O; Aubrey, Doug P

2016-01-01

The composition, integrity, and architecture of the macromolecular matrix of cell walls, collectively referred to as cell wall ultrastructure, exhibits variation across species and organs and among cell types within organs. Indirect approaches have suggested that modifications to cell wall ultrastructure occur in response to abiotic stress; however, modifications have not been directly observed. Glycome profiling was used to study cell wall ultrastructure by examining variation in composition and extractability of non-cellulosic glycans in cell walls of stem wood, roots, and needles of loblolly pine saplings exposed to high and low soil moisture. Soil moisture influenced physiological processes and the overall composition and extractability of cell wall components differed as a function of soil moisture treatments. The strongest response of cell wall ultrastructure to soil moisture was increased extractability of pectic backbone epitopes in the low soil moisture treatment. The higher abundance of these pectic backbone epitopes in the oxalate extract indicate that the loosening of cell wall pectic components could be associated with the release of pectic signals as a stress response. The increased extractability of pectic backbone epitopes in response to low soil moisture availability was more pronounced in stem wood than in roots or needles. Additional responses to low soil moisture availability were observed in lignin-associated carbohydrates released in chlorite extracts of stem wood, including an increased abundance of pectic arabinogalactan epitopes. Overall, these results indicate that cell walls of loblolly pine organs undergo changes in their ultrastructural composition and extractability as a response to soil moisture availability and that cell walls of the stem wood are more responsive to low soil moisture availability compared to cell walls of roots and needles. To our knowledge, this is the first direct evidence, delineated by glycomic analyses, that abiotic stress affects cell wall ultrastructure. This study is also unique in that glycome profiling of pine needles has never before been reported.

Cell Wall Ultrastructure of Stem Wood, Roots, and Needles of a Conifer Varies in Response to Moisture Availability

DOE PAGES

Pattathil, Sivakumar; Ingwers, Miles W.; Victoriano, Olivia L.; ...

2016-06-24

The composition, integrity, and architecture of the macromolecular matrix of cell walls, collectively referred to as cell wall ultrastructure, exhibits variation across species and organs and among cell types within organs. Indirect approaches have suggested that modifications to cell wall ultrastructure occur in response to abiotic stress; however, modifications have not been directly observed. Glycome profiling was used to study cell wall ultrastructure by examining variation in composition and extractability of non-cellulosic glycans in cell walls of stem wood, roots, and needles of loblolly pine saplings exposed to high and low soil moisture. Soil moisture influenced physiological processes and themore » overall composition and extractability of cell wall components differed as a function of soil moisture treatments. The strongest response of cell wall ultrastructure to soil moisture was increased extractability of pectic backbone epitopes in the low soil moisture treatment. The higher abundance of these pectic backbone epitopes in the oxalate extract indicate that the loosening of cell wall pectic components could be associated with the release of pectic signals as a stress response. The increased extractability of pectic backbone epitopes in response to low soil moisture availability was more pronounced in stem wood than in roots or needles. Additional responses to low soil moisture availability were observed in lignin associated carbohydrates released in chlorite extracts of stem wood, including an increased abundance of pectic arabinogalactan epitopes. Overall, these results indicate that cell walls of loblolly pine organs undergo changes in their ultrastructural composition and extractability as a response to soil moisture availability and that cell walls of the stem wood are more responsive to low soil moisture availability compared to cell walls of roots and needles. In conclusion, to our knowledge, this is the first direct evidence, delineated by glycomic analyses, that abiotic stress affects cell wall ultrastructure. This study is also unique in that glycome profiling of pine needles has never before been reported.« less

The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant.

PubMed

Zhang, Li; Lilley, Catherine J; Imren, Mustafa; Knox, J Paul; Urwin, Peter E

2017-01-01

Plant-parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida , Heterodera glycines , Heterodera avenae and Heterodera filipjevi , in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines . Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function.

The Complex Cell Wall Composition of Syncytia Induced by Plant Parasitic Cyst Nematodes Reflects Both Function and Host Plant

PubMed Central

Zhang, Li; Lilley, Catherine J.; Imren, Mustafa; Knox, J. Paul; Urwin, Peter E.

2017-01-01

Plant–parasitic cyst nematodes induce the formation of specialized feeding structures, syncytia, within their host roots. These unique plant organs serve as the sole nutrient resource for development and reproduction throughout the biotrophic interaction. The multinucleate syncytium, which arises through local dissolution of cell walls and protoplast fusion of multiple adjacent cells, has dense cytoplasm containing numerous organelles, surrounded by thickened outer cell walls that must withstand high turgor pressure. However, little is known about how the constituents of the syncytial cell wall and their conformation support its role during nematode parasitism. We used a set of monoclonal antibodies, targeted to a range of plant cell wall components, to reveal the microstructures of syncytial cell walls induced by four of the most economically important cyst nematode species, Globodera pallida, Heterodera glycines, Heterodera avenae and Heterodera filipjevi, in their respective potato, soybean, and spring wheat host roots. In situ fluorescence analysis revealed highly similar cell wall composition of syncytia induced by G. pallida and H. glycines. Both consisted of abundant xyloglucan, methyl-esterified homogalacturonan and pectic arabinan. In contrast, the walls of syncytia induced in wheat roots by H. avenae and H. filipjevi contain little xyloglucan but are rich in feruloylated xylan and arabinan residues, with variable levels of mixed-linkage glucan. The overall chemical composition of syncytial cell walls reflected the general features of root cell walls of the different host plants. We relate specific components of syncytial cell walls, such as abundant arabinan, methyl-esterification status of pectic homogalacturonan and feruloylation of xylan, to their potential roles in forming a network to support both the strength and flexibility required for syncytium function. PMID:28680436

RAPID 2D NMR METHOD FOR DETERMINING P-COUMARATE AND FERULATE LEVELS IN CORN (AND OTHER GRASS) CELL WALLS

USDA-ARS?s Scientific Manuscript database

Grass cell wall components are acylated by the hydroxycinnamates p-coumarate and ferulate. p-Coumarates largely acylate lignin sidechains, exclusively at the gamma-position, whereas ferulates primarily acylate the arabinosyl C5-position of arabinoxylans. Such components can be quantified as the corr...

Examination of water phase transitions in Loblolly pine and cell wall components by differential scanning calorimetry

Treesearch

Samuel L. Zelinka; Michael J. Lambrecht; Samuel V. Glass; Alex C. Wiedenhoeft; Daniel J. Yelle

2012-01-01

This paper examines phase transformations of water in wood and isolated wood cell wall components using differential scanning calorimetry with the purpose of better understanding "Type II water" or "freezable bound water" that has been reported for cellulose and other hydrophilic polymers. Solid loblolly pine (Pinus taeda...

A multi-component parallel-plate flow chamber system for studying the effect of exercise-induced wall shear stress on endothelial cells.

PubMed

Wang, Yan-Xia; Xiang, Cheng; Liu, Bo; Zhu, Yong; Luan, Yong; Liu, Shu-Tian; Qin, Kai-Rong

2016-12-28

In vivo studies have demonstrated that reasonable exercise training can improve endothelial function. To confirm the key role of wall shear stress induced by exercise on endothelial cells, and to understand how wall shear stress affects the structure and the function of endothelial cells, it is crucial to design and fabricate an in vitro multi-component parallel-plate flow chamber system which can closely replicate exercise-induced wall shear stress waveforms in artery. The in vivo wall shear stress waveforms from the common carotid artery of a healthy volunteer in resting and immediately after 30 min acute aerobic cycling exercise were first calculated by measuring the inner diameter and the center-line blood flow velocity with a color Doppler ultrasound. According to the above in vivo wall shear stress waveforms, we designed and fabricated a parallel-plate flow chamber system with appropriate components based on a lumped parameter hemodynamics model. To validate the feasibility of this system, human umbilical vein endothelial cells (HUVECs) line were cultured within the parallel-plate flow chamber under abovementioned two types of wall shear stress waveforms and the intracellular actin microfilaments and nitric oxide (NO) production level were evaluated using fluorescence microscope. Our results show that the trends of resting and exercise-induced wall shear stress waveforms, especially the maximal, minimal and mean wall shear stress as well as oscillatory shear index, generated by the parallel-plate flow chamber system are similar to those acquired from the common carotid artery. In addition, the cellular experiments demonstrate that the actin microfilaments and the production of NO within cells exposed to the two different wall shear stress waveforms exhibit different dynamic behaviors; there are larger numbers of actin microfilaments and higher level NO in cells exposed in exercise-induced wall shear stress condition than resting wall shear stress condition. The parallel-plate flow chamber system can well reproduce wall shear stress waveforms acquired from the common carotid artery in resting and immediately after exercise states. Furthermore, it can be used for studying the endothelial cells responses under resting and exercise-induced wall shear stress environments in vitro.

Following the compositional changes of fresh grape skin cell walls during the fermentation process in the presence and absence of maceration enzymes.

PubMed

Zietsman, Anscha J J; Moore, John P; Fangel, Jonatan U; Willats, William G T; Trygg, Johan; Vivier, Melané A

2015-03-18

Cell wall profiling technologies were used to follow compositional changes that occurred in the skins of grape berries (from two different ripeness levels) during fermentation and enzyme maceration. Multivariate data analysis showed that the fermentation process yielded cell walls enriched in hemicellulose components because pectin was solubilized (and removed) with a reduction as well as exposure of cell wall proteins usually embedded within the cell wall structure. The addition of enzymes caused even more depectination, and the enzymes unravelled the cell walls enabling better access to, and extraction of, all cell wall polymers. Overripe grapes had cell walls that were extensively hydrolyzed and depolymerized, probably by natural grape-tissue-ripening enzymes, and this enhanced the impact that the maceration enzymes had on the cell wall monosaccharide profile. The combination of the techniques that were used is an effective direct measurement of the hydrolysis actions of maceration enzymes on the cell walls of grape berry skin.

Pea Border Cell Maturation and Release Involve Complex Cell Wall Structural Dynamics1[OPEN

PubMed Central

2017-01-01

The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases, though, plant cells are programmed to detach, and root cap-derived border cells are examples of this. Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment. Their maturation and release is an important but poorly characterized cell separation event. To gain a deeper insight into the complex cellular dynamics underlying this process, we undertook a systematic, detailed analysis of pea (Pisum sativum) root tip cell walls. Our study included immunocarbohydrate microarray profiling, monosaccharide composition determination, Fourier-transformed infrared microspectroscopy, quantitative reverse transcription-PCR of cell wall biosynthetic genes, analysis of hydrolytic activities, transmission electron microscopy, and immunolocalization of cell wall components. Using this integrated glycobiology approach, we identified multiple novel modes of cell wall structural and compositional rearrangement during root cap growth and the release of border cells. Our findings provide a new level of detail about border cell maturation and enable us to develop a model of the separation process. We propose that loss of adhesion by the dissolution of homogalacturonan in the middle lamellae is augmented by an active biophysical process of cell curvature driven by the polarized distribution of xyloglucan and extensin epitopes. PMID:28400496

The Interplay between Cell Wall Mechanical Properties and the Cell Cycle in Staphylococcus aureus

PubMed Central

Bailey, Richard G.; Turner, Robert D.; Mullin, Nic; Clarke, Nigel; Foster, Simon J.; Hobbs, Jamie K.

2014-01-01

The nanoscale mechanical properties of live Staphylococcus aureus cells during different phases of growth were studied by atomic force microscopy. Indentation to different depths provided access to both local cell wall mechanical properties and whole-cell properties, including a component related to cell turgor pressure. Local cell wall properties were found to change in a characteristic manner throughout the division cycle. Splitting of the cell into two daughter cells followed a local softening of the cell wall along the division circumference, with the cell wall on either side of the division circumference becoming stiffer. Once exposed, the newly formed septum was found to be stiffer than the surrounding, older cell wall. Deeper indentations, which were affected by cell turgor pressure, did not show a change in stiffness throughout the division cycle, implying that enzymatic cell wall remodeling and local variations in wall properties are responsible for the evolution of cell shape through division. PMID:25468333

Determination of the cell wall polysaccharide and teichoic acid structures from Lactococcus lactis IL1403.

PubMed

Vinogradov, Evgeny; Sadovskaya, Irina; Courtin, Pascal; Kulakauskas, Saulius; Grard, Thierry; Mahony, Jennifer; van Sinderen, Douwe; Chapot-Chartier, Marie-Pierre

2018-06-15

In the lactic acid bacterium Lactococcus lactis, a cell wall polysaccharide (CWPS) is the bacterial receptor of the majority of infecting bacteriophages. The diversity of CWPS structures between strains explains, at least partially, the narrow host range of lactococcal phages. In the present work, we studied the polysaccharide components of the cell wall of the prototype L. lactis subsp. lactis strain IL1403. We identified a rhamnose-rich complex polysaccharide, carrying a glycerophosphate substitution, as the major component. Its structure was analyzed by 2D NMR spectroscopy, methylation analysis and MALDI-TOF MS and shown to be distinctly different from currently known lactococcal CWPS structures. It contains a linear backbone of repeated α-l-Rha disaccharide subunits, which is irregularly substituted with a trisaccharide occasionally bearing a glycerophosphate group. A poly (glycerol phosphate) teichoic acid, another important carbohydrate component of the IL1403 cell wall, was also isolated and structurally characterized. Copyright © 2018 Elsevier Ltd. All rights reserved.

Regulation of cell wall biosynthesis.

PubMed

Zhong, Ruiqin; Ye, Zheng-Hua

2007-12-01

Plant cell walls differ in their amount and composition among various cell types and even in different microdomains of the wall of a given cell. Plants must have evolved regulatory mechanisms controlling biosynthesis, targeted secretion, and assembly of wall components to achieve the heterogeneity in cell walls. A number of factors, including hormones, the cytoskeleton, glycosylphosphatidylinositol-anchored proteins, phosphoinositides, and sugar nucleotide supply, have been implicated in the regulation of cell wall biosynthesis or deposition. In the past two years, there have been important discoveries in transcriptional regulation of secondary wall biosynthesis. Several transcription factors in the NAC and MYB families have been shown to be the key switches for activation of secondary wall biosynthesis. These studies suggest a transcriptional network comprised of a hierarchy of transcription factors is involved in regulating secondary wall biosynthesis. Further investigation and integration of the regulatory players participating in the making of cell walls will certainly lead to our understanding of how wall amounts and composition are controlled in a given cell type. This may eventually allow custom design of plant cell walls on the basis of our needs.

Papillae formation on trichome cell walls requires the function of the mediator complex subunit Med25.

PubMed

Fornero, Christy; Suo, Bangxia; Zahde, Mais; Juveland, Katelyn; Kirik, Viktor

2017-11-01

Glassy Hair 1 (GLH1) gene that promotes papillae formation on trichome cell walls was identified as a subunit of the transcriptional mediator complex MED25. The MED25 gene is shown to be expressed in trichomes. The expression of the trichome development marker genes GLABRA2 (GL2) and Ethylene Receptor2 (ETR2) is not affected in the glh1 mutant. Presented data suggest that Arabidopsis MED25 mediator component is likely involved in the transcription of genes promoting papillae deposition in trichomes. The plant cell wall plays an important role in communication, defense, organization and support. The importance of each of these functions varies by cell type. Specialized cells, such as Arabidopsis trichomes, exhibit distinct cell wall characteristics including papillae. To better understand the molecular processes important for papillae deposition on the cell wall surface, we identified the GLASSY HAIR 1 (GLH1) gene, which is necessary for papillae formation. We found that a splice-site mutation in the component of the transcriptional mediator complex MED25 gene is responsible for the near papillae-less phenotype of the glh1 mutant. The MED25 gene is expressed in trichomes. Reporters for trichome developmental marker genes GLABRA2 (GL2) and Ethylene Receptor2 (ETR2) were not affected in the glh1 mutant. Collectively, the presented results show that MED25 is necessary for papillae formation on the cell wall surface of leaf trichomes and suggest that the Arabidopsis MED25 mediator component is likely involved in the transcription of a subset of genes that promote papillae deposition in trichomes.

Pea Border Cell Maturation and Release Involve Complex Cell Wall Structural Dynamics.

PubMed

Mravec, Jozef; Guo, Xiaoyuan; Hansen, Aleksander Riise; Schückel, Julia; Kračun, Stjepan Krešimir; Mikkelsen, Maria Dalgaard; Mouille, Grégory; Johansen, Ida Elisabeth; Ulvskov, Peter; Domozych, David S; Willats, William George Tycho

2017-06-01

The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases, though, plant cells are programmed to detach, and root cap-derived border cells are examples of this. Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment. Their maturation and release is an important but poorly characterized cell separation event. To gain a deeper insight into the complex cellular dynamics underlying this process, we undertook a systematic, detailed analysis of pea ( Pisum sativum ) root tip cell walls. Our study included immunocarbohydrate microarray profiling, monosaccharide composition determination, Fourier-transformed infrared microspectroscopy, quantitative reverse transcription-PCR of cell wall biosynthetic genes, analysis of hydrolytic activities, transmission electron microscopy, and immunolocalization of cell wall components. Using this integrated glycobiology approach, we identified multiple novel modes of cell wall structural and compositional rearrangement during root cap growth and the release of border cells. Our findings provide a new level of detail about border cell maturation and enable us to develop a model of the separation process. We propose that loss of adhesion by the dissolution of homogalacturonan in the middle lamellae is augmented by an active biophysical process of cell curvature driven by the polarized distribution of xyloglucan and extensin epitopes. © 2017 American Society of Plant Biologists. All Rights Reserved.

At the border: the plasma membrane-cell wall continuum.

PubMed

Liu, Zengyu; Persson, Staffan; Sánchez-Rodríguez, Clara

2015-03-01

Plant cells rely on their cell walls for directed growth and environmental adaptation. Synthesis and remodelling of the cell walls are membrane-related processes. During cell growth and exposure to external stimuli, there is a constant exchange of lipids, proteins, and other cell wall components between the cytosol and the plasma membrane/apoplast. 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 membrane, and its importance for plant tissue organization. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Tissue-specific distribution of hemicelluloses in six different sugarcane hybrids as related to cell wall recalcitrance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Costa, Thales H. F.; Vega-Sánchez, Miguel E.; Milagres, Adriane M. F.

Background: Grasses are lignocellulosic materials useful to supply the billion-tons annual requirement for renewable resources that aim to produce transportation fuels and a variety of chemicals. However, the polysaccharides contained in grass cell walls are built in a recalcitrant composite. Deconstruction of these cell walls is still a challenge for the energy-efficient and economically viable transformation of lignocellulosic materials. The varied tissue-specific distribution of cell wall components adds complexity to the origins of cell wall recalcitrance in grasses. This complexity usually led to empirically developed pretreatment processes to overcome recalcitrance. A further complication is that efficient pretreatment procedures generally treatmore » the less recalcitrant tissues more than necessary, which results in the generation of undesirable biomass degradation products. Results: Six different sugarcane hybrids were used as model grasses to evaluate the tissue-specific distribution of hemicelluloses and the role of these components in cell wall recalcitrance. Acetylated glucuronoarabinoxylan (GAX) occurs in all tissues. Mixed-linkage glucan (MLG) was relevant in the innermost regions of the sugarcane internodes (up to 15.4 % w/w), especially in the low-lignin content hybrids. Immunofluorescence microscopy showed that xylans predominated in vascular bundles, whereas MLG occurred mostly in the parenchyma cell walls from the pith region of the hybrids with low-lignin content. Evaluation of the digestibility of sugarcane polysaccharides by commercial enzymes indicated that the cell wall recalcitrance varied considerably along the internode regions and in the sugarcane hybrids. Pith regions of the hybrids with high MLG and low-lignin contents reached up to 85 % cellulose conversion after 72 h of hydrolysis, without any pretreatment. Conclusions: The collective characteristics of the internode regions were related to the varied recalcitrance found in the samples. Components such as lignin and GAX were critical for the increased recalcitrance, but low cellulose crystallinity index, high MLG contents, and highly substituted GAX contributed to the generation of a less recalcitrant material.« less

Tissue-specific distribution of hemicelluloses in six different sugarcane hybrids as related to cell wall recalcitrance

DOE PAGES

Costa, Thales H. F.; Vega-Sánchez, Miguel E.; Milagres, Adriane M. F.; ...

2016-05-04

Background: Grasses are lignocellulosic materials useful to supply the billion-tons annual requirement for renewable resources that aim to produce transportation fuels and a variety of chemicals. However, the polysaccharides contained in grass cell walls are built in a recalcitrant composite. Deconstruction of these cell walls is still a challenge for the energy-efficient and economically viable transformation of lignocellulosic materials. The varied tissue-specific distribution of cell wall components adds complexity to the origins of cell wall recalcitrance in grasses. This complexity usually led to empirically developed pretreatment processes to overcome recalcitrance. A further complication is that efficient pretreatment procedures generally treatmore » the less recalcitrant tissues more than necessary, which results in the generation of undesirable biomass degradation products. Results: Six different sugarcane hybrids were used as model grasses to evaluate the tissue-specific distribution of hemicelluloses and the role of these components in cell wall recalcitrance. Acetylated glucuronoarabinoxylan (GAX) occurs in all tissues. Mixed-linkage glucan (MLG) was relevant in the innermost regions of the sugarcane internodes (up to 15.4 % w/w), especially in the low-lignin content hybrids. Immunofluorescence microscopy showed that xylans predominated in vascular bundles, whereas MLG occurred mostly in the parenchyma cell walls from the pith region of the hybrids with low-lignin content. Evaluation of the digestibility of sugarcane polysaccharides by commercial enzymes indicated that the cell wall recalcitrance varied considerably along the internode regions and in the sugarcane hybrids. Pith regions of the hybrids with high MLG and low-lignin contents reached up to 85 % cellulose conversion after 72 h of hydrolysis, without any pretreatment. Conclusions: The collective characteristics of the internode regions were related to the varied recalcitrance found in the samples. Components such as lignin and GAX were critical for the increased recalcitrance, but low cellulose crystallinity index, high MLG contents, and highly substituted GAX contributed to the generation of a less recalcitrant material.« less

The Cell Wall of the Human Fungal Pathogen Aspergillus fumigatus: Biosynthesis, Organization, Immune Response, and Virulence.

PubMed

Latgé, Jean-Paul; Beauvais, Anne; Chamilos, Georgios

2017-09-08

More than 90% of the cell wall of the filamentous fungus Aspergillus fumigatus comprises polysaccharides. Biosynthesis of the cell wall polysaccharides is under the control of three types of enzymes: transmembrane synthases, which are anchored to the plasma membrane and use nucleotide sugars as substrates, and cell wall-associated transglycosidases and glycosyl hydrolases, which are responsible for remodeling the de novo synthesized polysaccharides and establishing the three-dimensional structure of the cell wall. For years, the cell wall was considered an inert exoskeleton of the fungal cell. The cell wall is now recognized as a living organelle, since the composition and cellular localization of the different constitutive cell wall components (especially of the outer layers) vary when the fungus senses changes in the external environment. The cell wall plays a major role during infection. The recognition of the fungal cell wall by the host is essential in the initiation of the immune response. The interactions between the different pattern-recognition receptors (PRRs) and cell wall pathogen-associated molecular patterns (PAMPs) orientate the host response toward either fungal death or growth, which would then lead to disease development. Understanding the molecular determinants of the interplay between the cell wall and host immunity is fundamental to combatting Aspergillus diseases.

Bacterial cell-wall recycling

PubMed Central

Johnson, Jarrod W.; Fisher, Jed F.; Mobashery, Shahriar

2012-01-01

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. In several Gram-negative pathogens, anhydro-MurNAc-peptide cell-wall fragments regulate AmpC β-lactamase induction. In some Gram-positive organisms, short peptides derived from the cell wall regulate the induction of both β-lactamase and β-lactam-resistant penicillin-binding proteins. 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. Indeed, such inhibitors improve the potency of β-lactams in vitro against inducible AmpC β-lactamase-producing bacteria. 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. PMID:23163477

Immunogold scanning electron microscopy can reveal the polysaccharide architecture of xylem cell walls

PubMed Central

Sun, Yuliang; Juzenas, Kevin

2017-01-01

Abstract Immunofluorescence microscopy (IFM) and immunogold transmission electron microscopy (TEM) are the two main techniques commonly used to detect polysaccharides in plant cell walls. Both are important in localizing cell wall polysaccharides, but both have major limitations, such as low resolution in IFM and restricted sample size for immunogold TEM. In this study, we have developed a robust technique that combines immunocytochemistry with scanning electron microscopy (SEM) to study cell wall polysaccharide architecture in xylem cells at high resolution over large areas of sample. Using multiple cell wall monoclonal antibodies (mAbs), this immunogold SEM technique reliably localized groups of hemicellulosic and pectic polysaccharides in the cell walls of five different xylem structures (vessel elements, fibers, axial and ray parenchyma cells, and tyloses). This demonstrates its important advantages over the other two methods for studying cell wall polysaccharide composition and distribution in these structures. In addition, it can show the three-dimensional distribution of a polysaccharide group in the vessel lateral wall and the polysaccharide components in the cell wall of developing tyloses. This technique, therefore, should be valuable for understanding the cell wall polysaccharide composition, architecture and functions of diverse cell types. PMID:28398585

Interactions of Condensed Tannins with Saccharomyces cerevisiae Yeast Cells and Cell Walls: Tannin Location by Microscopy.

PubMed

Mekoue Nguela, Julie; Vernhet, Aude; Sieczkowski, Nathalie; Brillouet, Jean-Marc

2015-09-02

Interactions between grape tannins/red wine polyphenols and yeast cells/cell walls was previously studied within the framework of red wine aging and the use of yeast-derived products as an alternative to aging on lees. Results evidenced a quite different behavior between whole cells (biomass grown to elaborate yeast-derived products, inactivated yeast, and yeast inactivated after autolysis) and yeast cell walls (obtained from mechanical disruption of the biomass). Briefly, whole cells exhibited a high capacity to irreversibly adsorb grape and wine tannins, whereas only weak interactions were observed for cell walls. This last point was quite unexpected considering the literature and called into question the real role of cell walls in yeasts' ability to fix tannins. In the present work, tannin location after interactions between grape and wine tannins and yeast cells and cell walls was studied by means of transmission electron microscopy, light epifluorescence, and confocal microscopy. Microscopy observations evidenced that if tannins interact with cell walls, and especially cell wall mannoproteins, they also diffuse freely through the walls of dead cells to interact with their plasma membrane and cytoplasmic components.

Resonant Soft X-ray Scattering of Cellulose Microstructure in Plant Primary Cell Walls

NASA Astrophysics Data System (ADS)

Ye, Dan; Kiemle, Sarah N.; Wang, Cheng; Cosgrove, Daniel J.; Gomez, Esther W.; Gomez, Enrique D.

Cellulosic biomass is the most abundant raw material available for the production of renewable and sustainable biofuels. Breaking down cellulose is the rate-limiting step in economical biofuel production; therefore, a detailed understanding of the microscopic structure of plant cell walls is required to develop efficient biofuel conversion methods. Primary cell walls are key determinants of plant growth and mechanics. Their structure is complex and heterogeneous, making it difficult to elucidate how various components such as pectin, hemicellulose, and cellulose contribute to the overall structure. The electron density of these wall components is similar; such that conventional hard X-ray scattering does not generate enough contrast to resolve the different elements of the polysaccharide network. The chemical specificity of resonant soft X-ray scattering allows contrast to be generated based on differences in chemistry of the different polysaccharides. By varying incident X-ray energies, we have achieved increased scattering contrast between cellulose and other polysaccharides from primary cell walls of onions. By performing scattering at certain energies, features of the network structure of the cell wall are resolved. From the soft X-ray scattering results, we obtained the packing distance of cellulose microfibrils embedded in the polysaccharide network.

Chapter 16: Lignin Visualization: Advanced Microscopy Techniques for Lignin Characterization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Yining; Donohoe, Bryon S

Visualization of lignin in plant cell walls, with both spatial and chemical resolution, is emerging as an important tool to understand lignin's role in the plant cell wall's nanoscale architecture and to understand and design processes intended to modify the lignin. As such, this chapter reviews recent advances in advanced imaging methods with respect to lignin in plant cell walls. This review focuses on the importance of lignin detection and localization for studies in both plant biology and biotechnology. Challenges going forward to identify and delineate lignin from other plant cell wall components and to quantitatively analyze lignin in wholemore » cell walls from native plant tissue and treated biomass are also discussed.« less

The receptor-like kinase AtVRLK1 regulates secondary cell wall thickening.

PubMed

Huang, Cheng; Zhang, Rui; Gui, Jinshan; Zhong, Yu; Li, Laigeng

2018-04-20

During the growth and development of land plants, some specialized cells, such as tracheary elements, undergo secondary cell wall thickening. Secondary cell walls contain additional lignin, compared with primary cell walls, thus providing mechanical strength and potentially improving defenses against pathogens. However, the molecular mechanisms that initiate wall thickening are unknown. In this study, we identified an Arabidopsis thaliana leucine-rich repeat receptor-like kinase, encoded by AtVRLK1 (Vascular-Related RLK 1), that is specifically expressed in cells undergoing secondary cell wall thickening. Suppression of AtVRLK1expression resulted in a range of phenotypes that included retarded early elongation of the inflorescence stem, shorter fibers, slower root growth, and shorter flower filaments. In contrast, upregulation of AtVRLK1 led to longer fiber cells, reduced secondary cell wall thickening in fiber and vessel cells, and defects in anther dehiscence. Molecular and cellular analyses showed that downregulation of AtVRLK1 promoted secondary cell wall thickening and upregulation of AtVRLK1 enhanced cell elongation and inhibited secondary cell wall thickening. We propose that AtVRLK1 functions as a signaling component in coordinating cell elongation and cell wall thickening during growth and development. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

Plant cell wall-mediated immunity: cell wall changes trigger disease resistance responses.

PubMed

Bacete, Laura; Mélida, Hugo; Miedes, Eva; Molina, Antonio

2018-02-01

Plants have evolved a repertoire of monitoring systems to sense plant morphogenesis and to face environmental changes and threats caused by different attackers. These systems integrate different signals into overreaching triggering pathways which coordinate developmental and defence-associated responses. The plant cell wall, a dynamic and complex structure surrounding every plant cell, has emerged recently as an essential component of plant monitoring systems, thus expanding its function as a passive defensive barrier. Plants have a dedicated mechanism for maintaining cell wall integrity (CWI) which comprises a diverse set of plasma membrane-resident sensors and pattern recognition receptors (PRRs). The PRRs perceive plant-derived ligands, such as peptides or wall glycans, known as damage-associated molecular patterns (DAMPs). These DAMPs function as 'danger' alert signals activating DAMP-triggered immunity (DTI), which shares signalling components and responses with the immune pathways triggered by non-self microbe-associated molecular patterns that mediate disease resistance. Alteration of CWI by impairment of the expression or activity of proteins involved in cell wall biosynthesis and/or remodelling, as occurs in some plant cell wall mutants, or by wall damage due to colonization by pathogens/pests, activates specific defensive and growth responses. Our current understanding of how these alterations of CWI are perceived by the wall monitoring systems is scarce and few plant sensors/PRRs and DAMPs have been characterized. The identification of these CWI sensors and PRR-DAMP pairs will help us to understand the immune functions of the wall monitoring system, and might allow the breeding of crop varieties and the design of agricultural strategies that would enhance crop disease resistance. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

DISTRIBUTION OF RADIOACTIVITY IN AUTOLYZED CELL WALL OF BACILLUS CEREUS DURING SPHEROPLAST FORMATION1

PubMed Central

Kronish, Donald P.; Mohan, Raam R.; Schwartz, Benjamin S.

1964-01-01

Kronish, Donald P. (Warner-Lambert Research Institute, Morris Plains, N.J.), Raam R. Mohan, and Benjamin S. Schwartz. Distribution of radioactivity in autolyzed cell wall of Bacillus cereus during spheroplast formation. J. Bacteriol. 87:581–587. 1964.—Spheroplasts of Bacillus cereus strain T were produced from cells grown in the presence of uniformly labeled C14-glucose. At regular intervals during spheroplast formation, enzymatically degraded cell wall was isolated by a new procedure. Radioactivity of solubilized cell wall in cell-free material increased from 2.5 to 42% of the total incorporated label during spheroplast formation. The rate of cell-wall degradation as measured by increase in radioactivity was biphasic with relative slopes of 2.0 and 5.0. During autolytic depolymerization of B. cereus cell wall, two major components were solubilized at different rates. Chemical fractionation revealed these to be a peptide and a mucopeptide. The possibility of two enzymes being involved in spheroplast formation and cell-wall degradation is discussed. Images PMID:14127573

Solution-state 2D NMR of ball-milled plant cell wall gels in DMSO-d6/pyridine-d5†

PubMed Central

Ralph, John

2014-01-01

NMR fingerprinting of the components of finely divided plant cell walls swelled in DMSO has been recently described. Cell wall gels, produced directly in the NMR tube with perdeutero-dimethylsulfoxide, allowed the acquisition of well resolved/dispersed 2D 13C–1H correlated solution-state NMR spectra of the entire array of wall polymers, without the need for component fractionation. That is, without actual solubilization, and without apparent structural modification beyond that inflicted by the ball milling and ultrasonication steps, satisfactorily interpretable spectra can be acquired that reveal compositional and structural details regarding the polysaccharide and lignin components in the wall. Here, the profiling method has been improved by using a mixture of perdeuterated DMSO and pyridine (4:1, v/v). Adding pyridine provided not only easier sample handling because of the better mobility compared to the DMSO-d6-only system but also considerably elevated intensities and improved resolution of the NMR spectra due to the enhanced swelling of the cell walls. This modification therefore provides a more rapid method for comparative structural evaluation of plant cell walls than is currently available. We examined loblolly pine (Pinus taeda, a gymnosperm), aspen (Populus tremuloides, an angiosperm), kenaf (Hibiscus cannabinus, an herbaceous plant), and corn (Zea mays L., a grass, i.e., from the Poaceae family). In principle, lignin composition (notably, the syringyl : guaiacyl : p-hydroxyphenyl ratio) can be quantified without the need for lignin isolation. Correlations for p-coumarate units in the corn sample are readily seen, and a variety of the ferulate correlations are also well resolved; ferulates are important components responsible for cell wall cross-linking in grasses. Polysaccharide anomeric correlations were tentatively assigned for each plant sample based on standard samples and various literature data. With the new potential for chemometric analysis using the 2D NMR fingerprint, this gel-state method may provide the basis for an attractive approach to providing a secondary screen for selecting biomass lines and for optimizing biomass processing and conversion efficiencies. PMID:20090974

Plant Fibre: Molecular Structure and Biomechanical Properties, of a Complex Living Material, Influencing Its Deconstruction towards a Biobased Composite

PubMed Central

Sorieul, Mathias; Dickson, Alan; Hill, Stefan J.; Pearson, Hamish

2016-01-01

Plant cell walls form an organic complex composite material that fulfils various functions. The hierarchical structure of this material is generated from the integration of its elementary components. This review provides an overview of wood as a composite material followed by its deconstruction into fibres that can then be incorporated into biobased composites. Firstly, the fibres are defined, and their various origins are discussed. Then, the organisation of cell walls and their components are described. The emphasis is on the molecular interactions of the cellulose microfibrils, lignin and hemicelluloses in planta. Hemicelluloses of diverse species and cell walls are described. Details of their organisation in the primary cell wall are provided, as understanding of the role of hemicellulose has recently evolved and is likely to affect our perception and future study of their secondary cell wall homologs. The importance of the presence of water on wood mechanical properties is also discussed. These sections provide the basis for understanding the molecular arrangements and interactions of the components and how they influence changes in fibre properties once isolated. A range of pulping processes can be used to individualise wood fibres, but these can cause damage to the fibres. Therefore, issues relating to fibre production are discussed along with the dispersion of wood fibres during extrusion. The final section explores various ways to improve fibres obtained from wood. PMID:28773739

Plant Fibre: Molecular Structure and Biomechanical Properties, of a Complex Living Material, Influencing Its Deconstruction towards a Biobased Composite.

PubMed

Sorieul, Mathias; Dickson, Alan; Hill, Stefan J; Pearson, Hamish

2016-07-26

Plant cell walls form an organic complex composite material that fulfils various functions. The hierarchical structure of this material is generated from the integration of its elementary components. This review provides an overview of wood as a composite material followed by its deconstruction into fibres that can then be incorporated into biobased composites. Firstly, the fibres are defined, and their various origins are discussed. Then, the organisation of cell walls and their components are described. The emphasis is on the molecular interactions of the cellulose microfibrils, lignin and hemicelluloses in planta . Hemicelluloses of diverse species and cell walls are described. Details of their organisation in the primary cell wall are provided, as understanding of the role of hemicellulose has recently evolved and is likely to affect our perception and future study of their secondary cell wall homologs. The importance of the presence of water on wood mechanical properties is also discussed. These sections provide the basis for understanding the molecular arrangements and interactions of the components and how they influence changes in fibre properties once isolated. A range of pulping processes can be used to individualise wood fibres, but these can cause damage to the fibres. Therefore, issues relating to fibre production are discussed along with the dispersion of wood fibres during extrusion. The final section explores various ways to improve fibres obtained from wood.

The Arabidopsis leucine-rich repeat receptor kinase MIK2/LRR-KISS connects cell wall integrity sensing, root growth and response to abiotic and biotic stresses

PubMed Central

Van der Does, Dieuwertje; Boutrot, Freddy; Vernhettes, Samantha; Tintor, Nico; Veerabagu, Manikandan; Miedes, Eva; Segonzac, Cécile; Hardtke, Christian S.; Molina, Antonio; Höfte, Herman; Hamann, Thorsten

2017-01-01

Plants actively perceive and respond to perturbations in their cell walls which arise during growth, biotic and abiotic stresses. However, few components involved in plant cell wall integrity sensing have been described to date. Using a reverse-genetic approach, we identified the Arabidopsis thaliana leucine-rich repeat receptor kinase MIK2 as an important regulator of cell wall damage responses triggered upon cellulose biosynthesis inhibition. Indeed, loss-of-function mik2 alleles are strongly affected in immune marker gene expression, jasmonic acid production and lignin deposition. MIK2 has both overlapping and distinct functions with THE1, a malectin-like receptor kinase previously proposed as cell wall integrity sensor. In addition, mik2 mutant plants exhibit enhanced leftward root skewing when grown on vertical plates. Notably, natural variation in MIK2 (also named LRR-KISS) has been correlated recently to mild salt stress tolerance, which we could confirm using our insertional alleles. Strikingly, both the increased root skewing and salt stress sensitivity phenotypes observed in the mik2 mutant are dependent on THE1. Finally, we found that MIK2 is required for resistance to the fungal root pathogen Fusarium oxysporum. Together, our data identify MIK2 as a novel component in cell wall integrity sensing and suggest that MIK2 is a nexus linking cell wall integrity sensing to growth and environmental cues. PMID:28604776

Secondary cell walls: biosynthesis, patterned deposition and transcriptional regulation.

PubMed

Zhong, Ruiqin; Ye, Zheng-Hua

2015-02-01

Secondary walls are mainly composed of cellulose, hemicelluloses (xylan and glucomannan) and lignin, and are deposited in some specialized cells, such as tracheary elements, fibers and other sclerenchymatous cells. Secondary walls provide strength to these cells, which lend mechanical support and protection to the plant body and, in the case of tracheary elements, enable them to function as conduits for transporting water. Formation of secondary walls is a complex process that requires the co-ordinated expression of secondary wall biosynthetic genes, biosynthesis and targeted secretion of secondary wall components, and patterned deposition and assembly of secondary walls. Here, we provide a comprehensive review of genes involved in secondary wall biosynthesis and deposition. Most of the genes involved in the biosynthesis of secondary wall components, including cellulose, xylan, glucomannan and lignin, have been identified and their co-ordinated activation has been shown to be mediated by a transcriptional network encompassing the secondary wall NAC and MYB master switches and their downstream transcription factors. It has been demonstrated that cortical microtubules and microtubule-associated proteins play important roles in the targeted secretion of cellulose synthase complexes, the oriented deposition of cellulose microfibrils and the patterned deposition of secondary walls. Further investigation of many secondary wall-associated genes with unknown functions will provide new insights into the mechanisms controlling the formation of secondary walls that constitute the bulk of plant biomass. © The Author 2014. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Chemical and enzymatic fractionation of cell walls from Fucales: insights into the structure of the extracellular matrix of brown algae.

PubMed

Deniaud-Bouët, Estelle; Kervarec, Nelly; Michel, Gurvan; Tonon, Thierry; Kloareg, Bernard; Hervé, Cécile

2014-10-01

Brown algae are photosynthetic multicellular marine organisms evolutionarily distant from land plants, with a distinctive cell wall. They feature carbohydrates shared with plants (cellulose), animals (fucose-containing sulfated polysaccharides, FCSPs) or bacteria (alginates). How these components are organized into a three-dimensional extracellular matrix (ECM) still remains unclear. Recent molecular analysis of the corresponding biosynthetic routes points toward a complex evolutionary history that shaped the ECM structure in brown algae. Exhaustive sequential extractions and composition analyses of cell wall material from various brown algae of the order Fucales were performed. Dedicated enzymatic degradations were used to release and identify cell wall partners. This approach was complemented by systematic chromatographic analysis to study polymer interlinks further. An additional structural assessment of the sulfated fucan extracted from Himanthalia elongata was made. The data indicate that FCSPs are tightly associated with proteins and cellulose within the walls. Alginates are associated with most phenolic compounds. The sulfated fucans from H. elongata were shown to have a regular α-(1→3) backbone structure, while an alternating α-(1→3), (1→4) structure has been described in some brown algae from the order Fucales. The data provide a global snapshot of the cell wall architecture in brown algae, and contribute to the understanding of the structure-function relationships of the main cell wall components. Enzymatic cross-linking of alginates by phenols may regulate the strengthening of the wall, and sulfated polysaccharides may play a key role in the adaptation to osmotic stress. The emergence and evolution of ECM components is further discussed in relation to the evolution of multicellularity in brown algae. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Raman imaging to investigate ultrastructure and composition of plant cell walls : distribution of lignin and cellulose in black spruce wood (Picea mariana)

Treesearch

Umesh P. Agarwal

2006-01-01

A detailed understanding of the structural organization of the cell wall of vascular plants is important from both the perspectives of plant biology and chemistry and of commercial utilization. A state-of-the-art 633-nm laser-based confocal Raman microscope was used to determine the distribution of cell wall components in the cross section of black spruce wood in situ...

The Specific Nature of Plant Cell Wall Polysaccharides 1

PubMed Central

Nevins, Donald J.; English, Patricia D.; Albersheim, Peter

1967-01-01

Polysaccharide compositions of cell walls were assessed by quantitative analyses of the component sugars. Cell walls were hydrolyzed in 2 n trifluoroacetic acid and the liberated sugars reduced to their respective alditols. The alditols were acetylated and the resulting alditol acetates separated by gas chromatography. Quantitative assay of the alditol acetates was accomplished by electronically integrating the detector output of the gas chromatograph. Myo-inositol, introduced into the sample prior to hydrolysis, served as an internal standard. The cell wall polysaccharide compositions of plant varieties within a given species are essentially identical. However, differences in the sugar composition were observed in cell walls prepared from different species of the same as well as of different genera. The fact that the wall compositions of different varieties of the same species are the same indicates that the biosynthesis of cell wall polysaccharides is genetically regulated. The cell walls of various morphological parts (roots, hypocotyls, first internodes and primary leaves) of bean plants were each found to have a characteristic sugar composition. It was found that the cell wall sugar composition of suspension-cultured sycamore cells could be altered by growing the cells on different carbon sources. This demonstrates that the biosynthesis of cell wall polysaccharides can be manipulated without fatal consequences. PMID:16656594

Molecular coordination of Staphylococcus aureus cell division

PubMed Central

Cotterell, Bryony E; Walther, Christa G; Fenn, Samuel J; Grein, Fabian; Wollman, Adam JM; Leake, Mark C; Olivier, Nicolas; Cadby, Ashley; Mesnage, Stéphane; Jones, Simon

2018-01-01

The bacterial cell wall is essential for viability, but despite its ability to withstand internal turgor must remain dynamic to permit growth and division. Peptidoglycan is the major cell wall structural polymer, whose synthesis requires multiple interacting components. The human pathogen Staphylococcus aureus is a prolate spheroid that divides in three orthogonal planes. Here, we have integrated cellular morphology during division with molecular level resolution imaging of peptidoglycan synthesis and the components responsible. Synthesis occurs across the developing septal surface in a diffuse pattern, a necessity of the observed septal geometry, that is matched by variegated division component distribution. Synthesis continues after septal annulus completion, where the core division component FtsZ remains. The novel molecular level information requires re-evaluation of the growth and division processes leading to a new conceptual model, whereby the cell cycle is expedited by a set of functionally connected but not regularly distributed components. PMID:29465397

Endoplasmic reticulum-derived reactive oxygen species (ROS) is involved in toxicity of cell wall stress to Candida albicans.

PubMed

Yu, Qilin; Zhang, Bing; Li, Jianrong; Zhang, Biao; Wang, Honggang; Li, Mingchun

2016-10-01

The cell wall is an important cell structure in both fungi and bacteria, and hence becomes a common antimicrobial target. The cell wall-perturbing agents disrupt synthesis and function of cell wall components, leading to cell wall stress and consequent cell death. However, little is known about the detailed mechanisms by which cell wall stress renders fungal cell death. In this study, we found that ROS scavengers drastically attenuated the antifungal effect of cell wall-perturbing agents to the model fungal pathogen Candida albicans, and these agents caused remarkable ROS accumulation and activation of oxidative stress response (OSR) in this fungus. Interestingly, cell wall stress did not cause mitochondrial dysfunction and elevation of mitochondrial superoxide levels. Furthermore, the iron chelator 2,2'-bipyridyl (BIP) and the hydroxyl radical scavengers could not attenuate cell wall stress-caused growth inhibition and ROS accumulation. However, cell wall stress up-regulated expression of unfold protein response (UPR) genes, enhanced protein secretion and promoted protein folding-related oxidation of Ero1, an important source of ROS production. These results indicated that oxidation of Ero1 in the endoplasmic reticulum (ER), rather than mitochondrial electron transport and Fenton reaction, contributed to cell wall stress-related ROS accumulation and consequent growth inhibition. Our findings uncover a novel link between cell wall integrity (CWI), ER function and ROS production in fungal cells, and shed novel light on development of strategies promoting the antifungal efficacy of cell wall-perturbing agents against fungal infections. Copyright © 2016 Elsevier Inc. All rights reserved.

Insights into cell wall structure of Sida hermaphrodita and its influence on recalcitrance.

PubMed

Damm, Tatjana; Pattathil, Sivakumar; Günl, Markus; Jablonowski, Nicolai David; O'Neill, Malcolm; Grün, Katharina Susanne; Grande, Philipp Michael; Leitner, Walter; Schurr, Ulrich; Usadel, Björn; Klose, Holger

2017-07-15

The perennial plant Sida hermaphrodita (Sida) is attracting attention as potential energy crop. Here, the first detailed view on non-cellulosic Sida cell wall polysaccharide composition, structure and architecture is given. Cell walls were prepared from Sida stems and sequentially extracted with aqueous buffers and alkali. The structures of the quantitatively predominant polysaccharides present in each fraction were determined by biochemical characterization, glycome profiling and mass spectrometry. The amounts of glucose released by Accellerase-1500 ® treatment of the cell wall and the cell wall residue remaining after each extraction were used to assess the roles of pectin and hemicellulose in the recalcitrance of Sida biomass. 4-O-Methyl glucuronoxylan with a low proportion of side substitutions was identified as the major non-cellulosic glycan component of Sida stem cell walls. Pectic polysaccharides and xylans were found to be associated with lignin, suggesting that these polysaccharides have roles in Sida cell wall recalcitrance to enzymatic hydrolysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biosynthesis of plant cell wall polysaccharides.

PubMed

Gibeaut, D M; Carpita, N C

1994-09-01

The cell wall is the principal structural element of plant form. Cellulose, long crystals of several dozen glucan chains, forms the microfibrillar foundation of plant cell walls and is synthesized at the plasma membrane. Except for callose, all other noncellulosic components are secreted to the cell surface and form a porous matrix assembled around the cellulose microfibrils. These diverse noncellulosic polysaccharides and proteins are made in the endomembrane system. Many questions about the biosynthesis and modification within the Golgi apparatus and integration of cell components at the cell surface remain unanswered. The lability of synthetic complexes upon isolation is one reason for slow progress. However, with new methods of membrane isolation and analysis of products in vitro, recent advances have been made in purifying active synthases from plasma membrane and Golgi apparatus. Likely synthase polypeptides have been identified by affinity-labeling techniques, but we are just beginning to understand the unique features of the coordinated assembly of complex polysaccharides. Nevertheless, such progress renews hope that the first gene of a synthase for a wall polysaccharide from higher plants is within our grasp.

Ripening-induced changes in grape skin proanthocyanidins modify their interaction with cell walls.

PubMed

Bindon, Keren A; Kennedy, James A

2011-03-23

Proanthocyanidins were isolated from the skins of Cabernet Sauvignon grapes at different stages of grape development in order to study the effect of proanthocyanidin modification on the interaction with grape cell wall material. After veraison, the degree of proanthocyanidin polymerization increased, and thereafter was variable between 24 and 33 subunits as ripening progressed. Affinity of skin cell wall material for proanthocyanidin decreased with proanthocyanidin ripeness following veraison. A significant negative relationship (R2=0.93) was found for average proanthocyanidin molecular mass and the proportion of high molecular mass proanthocyanidin adsorbed by skin cell wall material. This indicated that as proanthocyanidin polymerization increased, the affinity of a component of high molecular mass proanthocyanidins for skin cell wall material declined. This phenomenon was only associated with skin proanthocyanidins from colored grapes, as high molecular mass proanthocyanidins of equivalent subunit composition from colorless mutant Cabernet Sauvignon grapes had a higher affinity for skin cell wall material.

Use of Chemical Fractionation and Proton Nuclear Magnetic Resonance to Probe the Physical Structure of the Primary Plant Cell Wall 1

PubMed Central

Taylor, Iain E. P.; Wallace, Julia C.; MacKay, Alex L.; Volke, Frank

1990-01-01

Proton magnetic resonance has been used to monitor the microscopic physical properties of etiolated hypocotyl cell walls from Phaseolus vulgaris L. at all stages in a series of chemical fractionations with ammonium oxalate and potassium hydroxide. Solid echo measurements indicate that 75% of the polymers in the intact cell wall, including the cellulose and most of the hemicelluloses, are arranged such that there is almost complete restraint of molecular motion. The chemical fractionations generally altered the physical structures of the remaining cell wall components. Digestion with 0.25% ammonium oxalate/oxalic acid solubilized the pectin and increased the mobility of the hemicellulose I component. Extraction with 4% potassium hydroxide removed the hemicellulose I component and loosened the hemicellulose II. Further extraction with 24% potassium hydroxide removed the hemicellulose II and loosened some of the cellulose. The cellulose crystallinity, as monitored by Jeener echo measurements decreased from 83% to 63% during these fractionations. We conclude that, while hemicellulose I is firmly attached to hemicellulose II, it is not in a closely packed structure. Hemicellulose II is strongly bound to cellulose and has a much more closely packed structure. PMID:16667683

Colony Organization in the Green Alga Botryococcus braunii (Race B) Is Specified by a Complex Extracellular Matrix

PubMed Central

Weiss, Taylor L.; Roth, Robyn; Goodson, Carrie; Vitha, Stanislav; Black, Ian; Azadi, Parastoo; Rusch, Jannette; Holzenburg, Andreas

2012-01-01

Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quick-freeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell is surrounded by a fibrous β-1, 4- and/or β-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form “drapes” between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. We propose that retaining-wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM. PMID:22941913

Colony organization in the green alga Botryococcus braunii is specified by a complex extracellular matrix

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, Taylor L.; Roth, Robyn; Goodson, Carrie

Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quickfreeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell ismore » surrounded by a fibrous β-1, 4- and/or β-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form "drapes" between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. In addition, we propose that retaining-wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM.« less

Colony organization in the green alga Botryococcus braunii is specified by a complex extracellular matrix

DOE PAGES

Weiss, Taylor L.; Roth, Robyn; Goodson, Carrie; ...

2012-08-31

Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quickfreeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell ismore » surrounded by a fibrous β-1, 4- and/or β-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form "drapes" between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. In addition, we propose that retaining-wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM.« less

Processive movement of MreB-associated cell wall biosynthetic complexes in bacteria.

PubMed

Domínguez-Escobar, Julia; Chastanet, Arnaud; Crevenna, Alvaro H; Fromion, Vincent; Wedlich-Söldner, Roland; Carballido-López, Rut

2011-07-08

The peptidoglycan cell wall and the actin-like MreB cytoskeleton are major determinants of cell shape in rod-shaped bacteria. The prevailing model postulates that helical, membrane-associated MreB filaments organize elongation-specific peptidoglycan-synthesizing complexes along sidewalls. We used total internal reflection fluorescence microscopy to visualize the dynamic relation between MreB isoforms and cell wall synthesis in live Bacillus subtilis cells. During exponential growth, MreB proteins did not form helical structures. Instead, together with other morphogenetic factors, they assembled into discrete patches that moved processively along peripheral tracks perpendicular to the cell axis. Patch motility was largely powered by cell wall synthesis, and MreB polymers restricted diffusion of patch components in the membrane and oriented patch motion.

Endogenous pyrogen production by human blood monocytes stimulated by staphylococcal cell wall components.

PubMed

Oken, M M; Peterson, P K; Wilkinson, B J

1981-01-01

To determine the properties of Staphylococcus aureus contributing to its pyrogenicity, we compared, in human monocytes, endogenous pyrogen production stimulated by heat-killed S. aureus with that stimulated by purified S. aureus cell walls or by particulate peptidoglycan prepared from the same strain. Peptidoglycan, but not the purified cell wall preparation, was found comparable to S. aureus as an endogenous pyrogen stimulus. This finding was associated with a more effective monocyte phagocytosis of S. aureus and peptidoglycan as compared with that of purified cell walls. Lysostaphin digestion of peptidoglycan markedly reduced its pyrogenicity. To test whether the chemical composition of the ingested particles is important, latex particles were tested as possible stimuli for monocyte endogenous pyrogen release. Although 40 to 68% of monocytes ingested latex particles during the first hour, there was no evidence of endogenous pyrogen activity in the supernatant even when supernatants equivalent to 5.2 X 10(6) monocytes were tested. This study demonstrates that the pyrogenic moiety of the S. aureus cell wall resides in the peptidoglycan component. Phagocytosis is not in itself a pyrogenic stimulus, but rather serves as an effective mechanism to bring about contact between the chemical stimulus and the monocyte.

Plugging micro-leaks in multi-component, ceramic tubesheets with material leached therefrom

DOEpatents

Bieler, B.H.; Tsang, F.Y.

1985-03-19

Cracks, in ceramic wall members, on the order of 1 micron or less in width are plugged helium-tight by selectively leaching a component of the wall member with a solvent, letting the resultant leach form a liquid bridge within the crack, removing the solvent and sintering the resultant residue. This method is of particular value for remedying microcracks or channels in a cell member constituting a tubesheet in a hollow fiber type, high temperature battery cell, such as a sodium/sulfur cell, for example. 1 fig.

Plugging micro-leaks in multi-component, ceramic tubesheets with material leached therefrom

DOEpatents

Bieler, Barrie H.; Tsang, Floris Y.

1985-03-19

Cracks, in ceramic wall members, on the order of 1 micron or less in width are plugged helium-tight by selectively leaching a component of the wall member with a solvent, letting the resultant leach form a liquid bridge within the crack, removing the solvent and sintering the resultant residue. This method is of particular value for remedying microcracks or channels in a cell member constituting a tubesheet in a hollow fiber type, high temperature battery cell, such as a sodium/sulfur cell, for example.

Distinct roles of cell wall biogenesis in yeast morphogenesis as revealed by multivariate analysis of high-dimensional morphometric data

PubMed Central

Okada, Hiroki; Ohnuki, Shinsuke; Roncero, Cesar; Konopka, James B.; Ohya, Yoshikazu

2014-01-01

The cell wall of budding yeast is a rigid structure composed of multiple components. To thoroughly understand its involvement in morphogenesis, we used the image analysis software CalMorph to quantitatively analyze cell morphology after treatment with drugs that inhibit different processes during cell wall synthesis. Cells treated with cell wall–affecting drugs exhibited broader necks and increased morphological variation. Tunicamycin, which inhibits the initial step of N-glycosylation of cell wall mannoproteins, induced morphologies similar to those of strains defective in α-mannosylation. The chitin synthase inhibitor nikkomycin Z induced morphological changes similar to those of mutants defective in chitin transglycosylase, possibly due to the critical role of chitin in anchoring the β-glucan network. To define the mode of action of echinocandin B, a 1,3-β-glucan synthase inhibitor, we compared the morphology it induced with mutants of Fks1 that contains the catalytic domain for 1,3-β-glucan synthesis. Echinocandin B exerted morphological effects similar to those observed in some fks1 mutants, with defects in cell polarity and reduced glucan synthesis activity, suggesting that echinocandin B affects not only 1,3-β-glucan synthesis, but also another functional domain. Thus our multivariate analyses reveal discrete functions of cell wall components and increase our understanding of the pharmacology of antifungal drugs. PMID:24258022

Changes in structural and chemical components of wood delignified by fungi

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchette, R.A.; Otjen, L.; Effland, M.J.

1985-01-01

Cerrena unicolor, Ganoderma applanatum, Ischnoderma resinosum and Poria medulla-panis were associated with birch (Betula papyrifera) wood that had been selectively delignified in the forest. Preferential lignin degradation was not uniformly distributed throughout the decayed wood. A typical white rot causing a simultaneous removal of all cell wall components was also present. In the delignified wood, 95 to 98% of the lignin was removed as well as substantial amounts of hemicelluloses. Scanning and transmission electron microscopy were used to identify the micromorphological and ultrastructural changes that occurred in the cells during degradation. In delignified areas the compound middle lamella was extensivelymore » degraded causing a defibration of cells. The secondary wall, especially the S2 layer, remained relatively unaltered. In simultaneously white-rotted wood all cell wall layers were progressively removed from the lumen toward the middle lamella causing erosion troughs or holes to form. Large voids filled with fungal mycelia resulted from a coalition of degraded areas. Birch wood decayed in laboratory soil-block tests was also intermittently delignified, selective delignification, sparsely distributed throughout the wood, and a simultaneous rot resulting in the removal of all cell wall components were evident. SEM appears to be an appropriate technique for examining selectively delignified decayed wood. 30 references.« less

Boron reduces aluminum-induced growth inhibition, oxidative damage and alterations in the cell wall components in the roots of trifoliate orange.

PubMed

Riaz, Muhammad; Yan, Lei; Wu, Xiuwen; Hussain, Saddam; Aziz, Omar; Imran, Muhammad; Rana, Muhammad Shoaib; Jiang, Cuncang

2018-05-30

Aluminum (Al) toxicity is a major restriction for crops production on acidic soils. The primary symptom of aluminum toxicity is visible in the roots of plants. Recently, several studies reported the alleviation of Al toxicity by the application of Boron (B), however, the information how B alleviates Al toxicity is not well understood. Thus, we investigated the ameliorative response of B on Al-induced growth inhibition, oxidative damages, and variations in the cell wall components in trifoliate orange roots. The results indicated that plants under Al stress experienced a substantial decrement in root length and overall plant growth. The supply of B improved the root elongation by eliminating oxidative stress, membrane peroxidation, membrane leakage, and cell death produced under Al toxicity. Moreover, accumulation of Al on the cell wall and alteration in the cell wall components might be one of the causes resulting in the quick inhibition of root elongation under B-starvation circumstances by providing susceptible negative charges on pectin matrix for binding of Al. The results provide a useful understanding of the insight into mechanisms of B-induced mitigation of Al toxicity especially in the trifoliate orange that might be helpful in the production of crops on acidic soils. Copyright © 2018 Elsevier Inc. All rights reserved.

Report on the Current Inventory of the Toolbox for Plant Cell Wall Analysis: Proteinaceous and Small Molecular Probes

PubMed Central

Rydahl, Maja G.; Hansen, Aleksander R.; Kračun, Stjepan K.; Mravec, Jozef

2018-01-01

Plant cell walls are highly complex structures composed of diverse classes of polysaccharides, proteoglycans, and polyphenolics, which have numerous roles throughout the life of a plant. Significant research efforts aim to understand the biology of this cellular organelle and to facilitate cell-wall-based industrial applications. To accomplish this, researchers need to be provided with a variety of sensitive and specific detection methods for separate cell wall components, and their various molecular characteristics in vitro as well as in situ. Cell wall component-directed molecular detection probes (in short: cell wall probes, CWPs) are an essential asset to the plant glycobiology toolbox. To date, a relatively large set of CWPs has been produced—mainly consisting of monoclonal antibodies, carbohydrate-binding modules, synthetic antibodies produced by phage display, and small molecular probes. In this review, we summarize the state-of-the-art knowledge about these CWPs; their classification and their advantages and disadvantages in different applications. In particular, we elaborate on the recent advances in non-conventional approaches to the generation of novel CWPs, and identify the remaining gaps in terms of target recognition. This report also highlights the addition of new “compartments” to the probing toolbox, which is filled with novel chemical biology tools, such as metabolic labeling reagents and oligosaccharide conjugates. In the end, we also forecast future developments in this dynamic field. PMID:29774041

Molecular regulation of plant cell wall extensibility

NASA Technical Reports Server (NTRS)

Cosgrove, D. J.

1998-01-01

Gravity responses in plants often involve spatial and temporal changes in cell growth, which is regulated primarily by controlling the ability of the cell wall to extend. The wall is thought to be a cellulose-hemicellulose network embedded in a hydrated matrix of complex polysaccharides and a small amount of structural protein. The wall extends by a form of polymer creep, which is mediated by expansins, a novel group of wall-loosening proteins. Expansins were discovered during a molecular dissection of the "acid growth" behavior of cell walls. Expansin alters the rheology of plant walls in profound ways, yet its molecular mechanism of action is still uncertain. It lacks detectable hydrolytic activity against the major components of the wall, but it is able to disrupt noncovalent adhesion between wall polysaccharides. The discovery of a second family of expansins (beta-expansins) sheds light on the biological role of a major group of pollen allergens and implies that expansins have evolved for diverse developmental functions. Finally, the contribution of other processes to wall extensibility is briefly summarized.

Acid-growth response and alpha-expansins in suspension cultures of bright yellow 2 tobacco

NASA Technical Reports Server (NTRS)

Link, B. M.; Cosgrove, D. J.

1998-01-01

The possibility that Bright Yellow 2 (BY2) tobacco (Nicotiana tabacum L.) suspension-cultured cells possess an expansin-mediated acid-growth mechanism was examined by multiple approaches. BY2 cells grew three times faster upon treatment with fusicoccin, which induces an acidification of the cell wall. Exogenous expansins likewise stimulated BY2 cell growth 3-fold. Protein extracted from BY2 cell walls possessed the expansin-like ability to induce extension of isolated walls. In western-blot analysis of BY2 wall protein, one band of 29 kD was recognized by anti-expansin antibody. Six different classes of alpha-expansin mRNA were identified in a BY2 cDNA library. Northern-blot analysis indicated moderate to low abundance of multiple alpha-expansin mRNAs in BY2 cells. From these results we conclude that BY2 suspension-cultured cells have the necessary components for expansin-mediated cell wall enlargement.

THE PRESENCE OF A GROUP A VARIANT-LIKE ANTIGEN IN STREPTOCOCCI OF OTHER GROUPS WITH SPECIAL REFERENCE TO GROUP N

PubMed Central

Elliott, S. D.; Hayward, John; Liu, T. Y.

1971-01-01

A Group A variant-like antigen has been detected in streptococci belonging to Groups D, E, G, M, and N. In Groups D and N the variant-like antigen was located in the streptococcal cell walls. In two strains of Group N streptococci (C559 and B209) the cell walls were chemically different and serologically distinct. In strain C559 N-acetylgalactosamine, and in strain B209, N-acetylglucosamine were the major determinants of serological specificity. The cell walls of strain C559 contained at least three serologically reactive components: a rhamnose-containing fraction that precipitated with an antiserum to Group A-variant carbohydrate; a strain-specific polysaccharide composed of galactosamine and glucosamine, both in the N-acetylated form and probably polymerized with an unidentified phosphorylated substance; and a component of unknown composition serologically related to a Group D streptococcus strain C3 (S. durans). An analogy is drawn between the cell wall structure in streptococcus and Salmonella. PMID:5111438

The cell wall: a carbohydrate armour for the fungal cell.

PubMed

Latgé, Jean-Paul

2007-10-01

The cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched beta1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only beta1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.

A toolbox to measure changes in the cell wall glycopolymer composition during differentiation of Streptomyces coelicolor A3(2).

PubMed

Sigle, Steffen; Steblau, Nadja; Wohlleben, Wolfgang; Muth, Günther

2016-09-01

Cell wall glycopolymers (CWG) represent an important component of the Gram-positive cell envelope with many biological functions. The mycelial soil bacterium Streptomyces coelicolor A3(2) incorporates two distinct CWGs, polydiglycosylphosphate (PDP) and teichulosonic acid, into the cell wall of its vegetative mycelium but only little is known about their role in the complex life cycle of this microorganism. In this study we established assays to measure the total amount of CWGs in mycelial cell walls and spore walls, to quantify the individual CWGs and to determine the length of PDP. By applying these assays, we discovered that the relative amount of CWGs, especially of PDP, is reduced in spores compared to vegetative mycelium. Furthermore we found that PDP extracted from mycelial cell walls consisted of at least 19 repeating units, whereas spore walls contained substantially longer PDP polymers. Copyright © 2016 Elsevier B.V. All rights reserved.

30 years of battling the cell wall.

PubMed

Latgé, J P

2017-01-01

In Aspergillus fumigatus, like in other pathogenic fungi, the cell wall is essential for fungal growth as well as for resisting environmental stresses such as phagocytic killing. Most of the chemical analyses undertaken on the cell wall of A. fumigatus are focused on the mycelial cell wall because it is the vegetative stage of the fungus. However, the cell walls of the mycelium and conidium (which is the infective propagule) are different especially at the level of the surface layer, which plays a significant role in the interaction between A. fumigatus conidia and phagocytic cells of the immune system. In spite of the essential function of the cell wall in fungal life, progresses have been extremely slow in the understanding of biosynthesis as well in the identification of the key host responses against the cell wall components. A major difficulty is the fact that the composition and structural organization of the cell wall is not immutably set and is constantly reshuffled depending on the environmental conditions. © The Author 2016. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Higuchi, T.

A textbook containing 22 chapters by various authors covers the structure of wood, the localization of polysaccharides and lignins in wood cell walls, metabolism and synthetic function of cambial tissue, cell organelles and their function in the biosynthesis of cell wall components, biosynthesis of plant cell wall polysaccharides, lignin, cutin, suberin and associated waxes, phenolic acids and monolignols, quinones, flavonoids, tannins, stilbenes and terpenoid wood extractives, the occurrence of extractives, the metabolism of phenolic acids, wood degradation by micro-organisms and fungi, and biodegradation of cellulose, hemicelluloses, lignin, and aromatic extractives of wood. An index is included.

DBIO Best Thesis Award: Mechanics, Dynamics, and Organization of the Bacterial Cytoskeleton and Cell Wall

NASA Astrophysics Data System (ADS)

Wang, Siyuan

2012-02-01

Bacteria come in a variety of shapes. While the peptidoglycan (PG) cell wall serves as an exoskeleton that defines the static cell shape, the internal bacterial cytoskeleton mediates cell shape by recruiting PG synthesis machinery and thus defining the pattern of cell-wall synthesis. While much is known about the chemistry and biology of the cytoskeleton and cell wall, much of their biophysics, including essential aspects of the functionality, dynamics, and organization, remain unknown. This dissertation aims to elucidate the detailed biophysical mechanisms of cytoskeleton guided wall synthesis. First, I find that the bacterial cytoskeleton MreB contributes nearly as much to the rigidity of an Escherichia coli cell as the cell wall. This conclusion implies that the cytoskeletal polymer MreB applies meaningful force to the cell wall, an idea favored by theoretical modeling of wall growth, and suggests an evolutionary origin of cytoskeleton-governed cell rigidity. Second, I observe that MreB rotates around the long axis of E. coli, and the motion depends on wall synthesis. This is the first discovery of a cell-wall assembly driven molecular motor in bacteria. Third, I prove that both cell-wall synthesis and the PG network have chiral ordering, which is established by the spatial pattern of MreB. This work links the molecular structure of the cytoskeleton and of the cell wall with organismal-scale behavior. Finally, I develop a mathematical model of cytoskeleton-cell membrane interactions, which explains the preferential orientation of different cytoskeleton components in bacteria.

Evolution and diversity of plant cell walls: from algae to flowering plants.

PubMed

Popper, Zoë A; Michel, Gurvan; Hervé, Cécile; Domozych, David S; Willats, William G T; Tuohy, Maria G; Kloareg, Bernard; Stengel, Dagmar B

2011-01-01

All photosynthetic multicellular Eukaryotes, including land plants and algae, have cells that are surrounded by a dynamic, complex, carbohydrate-rich cell wall. The cell wall exerts considerable biological and biomechanical control over individual cells and organisms, thus playing a key role in their environmental interactions. This has resulted in compositional variation that is dependent on developmental stage, cell type, and season. Further variation is evident that has a phylogenetic basis. Plants and algae have a complex phylogenetic history, including acquisition of genes responsible for carbohydrate synthesis and modification through a series of primary (leading to red algae, green algae, and land plants) and secondary (generating brown algae, diatoms, and dinoflagellates) endosymbiotic events. Therefore, organisms that have the shared features of photosynthesis and possession of a cell wall do not form a monophyletic group. Yet they contain some common wall components that can be explained increasingly by genetic and biochemical evidence.

Penium margaritaceum as a model organism for cell wall analysis of expanding plant cells.

PubMed

Rydahl, Maja G; Fangel, Jonatan U; Mikkelsen, Maria Dalgaard; Johansen, I Elisabeth; Andreas, Amanda; Harholt, Jesper; Ulvskov, Peter; Jørgensen, Bodil; Domozych, David S; Willats, William G T

2015-01-01

The growth of a plant cell encompasses a complex set of subcellular components interacting in a highly coordinated fashion. Ultimately, these activities create specific cell wall structural domains that regulate the prime force of expansion, internally generated turgor pressure. The precise organization of the polymeric networks of the cell wall around the protoplast also contributes to the direction of growth, the shape of the cell, and the proper positioning of the cell in a tissue. In essence, plant cell expansion represents the foundation of development. Most studies of plant cell expansion have focused primarily upon late divergent multicellular land plants and specialized cell types (e.g., pollen tubes, root hairs). Here, we describe a unicellular green alga, Penium margaritaceum (Penium), which can serve as a valuable model organism for understanding cell expansion and the underlying mechanics of the cell wall in a single plant cell.

Distribution of alginate and cellulose and regulatory role of calcium in the cell wall of the brown alga Ectocarpus siliculosus (Ectocarpales, Phaeophyceae).

PubMed

Terauchi, Makoto; Nagasato, Chikako; Inoue, Akira; Ito, Toshiaki; Motomura, Taizo

2016-08-01

This work investigated a correlation between the three-dimensional architecture and compound-components of the brown algal cell wall. Calcium greatly contributes to the cell wall integrity. Brown algae have a unique cell wall consisting of alginate, cellulose, and sulfated polysaccharides. However, the relationship between the architecture and the composition of the cell wall is poorly understood. Here, we investigated the architecture of the cell wall and the effect of extracellular calcium in the sporophyte and gametophyte of the model brown alga, Ectocarpus siliculosus (Dillwyn) Lyngbye, using transmission electron microscopy, histochemical, and immunohistochemical studies. The lateral cell wall of vegetative cells of the sporophyte thalli had multilayered architecture containing electron-dense and negatively stained fibrils. Electron tomographic analysis showed that the amount of the electron-dense fibrils and the junctions was different between inner and outer layers, and between the perpendicular and tangential directions of the cell wall. By immersing the gametophyte thalli in the low-calcium (one-eighth of the normal concentration) artificial seawater medium, the fibrous layers of the lateral cell wall of vegetative cells became swollen. Destruction of cell wall integrity was also induced by the addition of sorbitol. The results demonstrated that electron-dense fibrils were composed of alginate-calcium fibrous gels, and electron negatively stained fibrils were crystalline cellulose microfibrils. It was concluded that the spatial arrangement of electron-dense fibrils was different between the layers and between the directions of the cell wall, and calcium was necessary for maintaining the fibrous layers in the cell wall. This study provides insights into the design principle of the brown algal cell wall.

Chalcone Synthase (CHS) Gene Suppression in Flax Leads to Changes in Wall Synthesis and Sensing Genes, Cell Wall Chemistry and Stem Morphology Parameters

PubMed Central

Zuk, Magdalena; Działo, Magdalena; Richter, Dorota; Dymińska, Lucyna; Matuła, Jan; Kotecki, Andrzej; Hanuza, Jerzy; Szopa, Jan

2016-01-01

The chalcone synthase (CHS) gene controls the first step in the flavonoid biosynthesis. In flax, CHS down-regulation resulted in tannin accumulation and reduction in lignin synthesis, but plant growth was not affected. This suggests that lignin content and thus cell wall characteristics might be modulated through CHS activity. This study investigated the possibility that CHS affects cell wall sensing as well as polymer content and arrangement. CHS-suppressed and thus lignin-reduced plants showed significant changes in expression of genes involved in both synthesis of components and cell wall sensing. This was accompanied by increased levels of cellulose and hemicellulose. CHS-reduced flax also showed significant changes in morphology and arrangement of the cell wall. The stem tissue layers were enlarged averagely twofold compared to the control, and the number of fiber cells more than doubled. The stem morphology changes were accompanied by reduction of the crystallinity index of the cell wall. CHS silencing induces a signal transduction cascade that leads to modification of plant metabolism in a wide range and thus cell wall structure. PMID:27446124

Transmission electron microscopy, fluorescence microscopy, and confocal raman microscopic analysis of ultrastructural and compositional heterogeneity of Cornus alba L. wood cell wall.

PubMed

Ma, Jianfeng; Ji, Zhe; Zhou, Xia; Zhang, Zhiheng; Xu, Feng

2013-02-01

Transmission electron microscopy (TEM), fluorescence microscopy, and confocal Raman microscopy can be used to characterize ultrastructural and compositional heterogeneity of plant cell walls. In this study, TEM observations revealed the ultrastructural characterization of Cornus alba L. fiber, vessel, axial parenchyma, ray parenchyma, and pit membrane between cells, notably with the ray parenchyma consisting of two well-defined layers. Fluorescence microscopy evidenced that cell corner middle lamella was more lignified than adjacent compound middle lamella and secondary wall with variation in lignification level from cell to cell. In situ Raman images showed that the inhomogeneity in cell wall components (cellulose and lignin) among different cells and within morphologically distinct cell wall layers. As the significant precursors of lignin biosynthesis, the pattern of coniferyl alcohol and aldehyde (joint abbreviation Lignin-CAA for both structures) distribution in fiber cell wall was also identified by Raman images, with higher concentration occurring in the fiber secondary wall where there was the highest cellulose concentration. Moreover, noteworthy was the observation that higher concentration of lignin and very minor amounts of cellulose were visualized in the pit membrane areas. These complementary microanalytical methods provide more accurate and complete information with regard to ultrastructural and compositional characterization of plant cell walls.

Using biomimetic cell wall models to identify new plant lignin bioengineering targets for improving forage and biomass utilization

USDA-ARS?s Scientific Manuscript database

Bioengineering of lignin to contain atypical components derived from other metabolic pathways is increasingly being pursued to custom design lignified cell walls that are inherently more digestible by livestock or more easily pretreated and saccharified for biofuel production. Because plants produce...

Cell wall chemistry

Treesearch

Roger M. Rowell; Roger Pettersen; James S. Han; Jeffrey S. Rowell; Mandla A. Tshabalala

2005-01-01

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,...

The mechanism by which arabinoxylanases can recognize highly decorated xylans

USDA-ARS?s Scientific Manuscript database

The enzymatic degradation of plant cell walls is an important biological process of increasing environmental and industrial significance. Xylan, a major component of the plant cell wall, consists of a backbone of beta 1,4-xylose (Xylp) units that are often decorated with arabinofuranose (Araf) side ...

Compositional analysis of Chinese water chestnut (Eleocharis dulcis) cell-wall material from parenchyma, epidermis, and subepidermal tissues.

PubMed

Grassby, Terri; Jay, Andrew J; Merali, Zara; Parker, Mary L; Parr, Adrian J; Faulds, Craig B; Waldron, Keith W

2013-10-09

Chinese water chestnut (Eleocharis dulcis (Burman f.) Trin ex Henschel) is a corm consumed globally in Oriental-style cuisine. The corm consists of three main tissues, the epidermis, subepidermis, and parenchyma; the cell walls of which were analyzed for sugar, phenolic, and lignin content. Sugar content, measured by gas chromatography, was higher in the parenchyma cell walls (931 μg/mg) than in the subepidermis (775 μg/mg) or epidermis (685 μg/mg). The alkali-extractable phenolic content, measured by high-performance liquid chromatography, was greater in the epidermal (32.4 μg/mg) and subepidermal cell walls (21.7 μg/mg) than in the cell walls of the parenchyma (12.3 μg/mg). The proportion of diferulic acids was higher in the parenchyma. The Klason lignin content of epidermal and subepidermal cell walls was ~15%. Methylation analysis of Chinese water chestnut cell-wall polysaccharides identified xyloglucan as the predominant hemicellulose in the parenchyma for the first time, and also a significant pectin component, similar to other nongraminaceous monocots.

Binding mechanism of patulin to heat-treated yeast cell.

PubMed

Guo, C; Yuan, Y; Yue, T; Hatab, S; Wang, Z

2012-12-01

This study aims to assess the removal mechanism of patulin using heat-treated Saccharomyces cerevisiae cells and identify the role of different cell wall components in the binding process. In order to understand the binding mechanism, viable cells, heat-treated cells, cell wall and intracellular extract were performed to assess their ability to remove patulin. Additionally, the effects of chemical and enzymatic treatments of yeast on the binding ability were tested. The results showed that there was no significant difference between viable (53·28%) and heat-treated yeast cells (51·71%) in patulin binding. In addition, the cell wall fraction decreased patulin by 35·05%, and the cell extract nearly failed to bind patulin. Treatments with protease E, methanol, formaldehyde, periodate or urea significantly decreased (P < 0·05) the ability of heat-treated cells to remove patulin. Fourier transform infrared (FTIR) analysis indicated that more functional groups were involved in the binding process of heat-treated cells. Polysaccharides and protein are important components of yeast cell wall involved in patulin removal. In addition, hydrophobic interactions play a major role in binding processes. Heat-treated S. cerevisiae cells could be used to control patulin contamination in the apple juice industry. Also, our results proof that the patulin removal process is based mainly on the adsorption not degradation. © 2012 The Society for Applied Microbiology.

Bio-chemo-mechanical models of vascular mechanics

PubMed Central

Kim, Jungsil; Wagenseil, Jessica E.

2014-01-01

Models of vascular mechanics are necessary to predict the response of an artery under a variety of loads, for complex geometries, and in pathological adaptation. Classic constitutive models for arteries are phenomenological and the fitted parameters are not associated with physical components of the wall. Recently, microstructurally-linked models have been developed that associate structural information about the wall components with tissue-level mechanics. Microstructurally-linked models are useful for correlating changes in specific components with pathological outcomes, so that targeted treatments may be developed to prevent or reverse the physical changes. However, most treatments, and many causes, of vascular disease have chemical components. Chemical signaling within cells, between cells, and between cells and matrix constituents affects the biology and mechanics of the arterial wall in the short- and long-term. Hence, bio-chemo-mechanical models that include chemical signaling are critical for robust models of vascular mechanics. This review summarizes bio-mechanical and bio-chemo-mechanical models with a focus on large elastic arteries. We provide applications of these models and challenges for future work. PMID:25465618

Structure of the Cell Wall of Bacillus stearothermophilus: Mode of Action of a Thermophilic Bacteriophage Lytic Enzyme

PubMed Central

Welker, N. E.

1971-01-01

The mode of action of a bacteriophage lytic enzyme on cell walls of Bacillus stearothermophilus (NCA 1503-4R) has been investigated. The enzyme is an endopeptidase which catalyzes the hydrolysis of the l-alanyl-d-glutamyl linkage in peptide subunits of the cell wall peptidoglycan. Preliminary studies on the soluble components in lytic cell wall digests indicate that the glycan moiety is composed of alternating glucosamine and muramic acid; one half of the muramic acid residues contain the tripeptide, l-alanyl-d-glutamyldiaminopimelic acid, and the remaining residues contain the tetrapeptide, l-alanyl-d-glutamyldiaminopimeyl-d-alanine. Almost one half of the peptide subunits are involved in cross-linkages of chemotype I. A structure for the cell wall peptidoglycan is proposed in the light of these findings. PMID:4255338

Pectic homogalacturonan masks abundant sets of xyloglucan epitopes in plant cell walls.

PubMed

Marcus, Susan E; Verhertbruggen, Yves; Hervé, Cécile; Ordaz-Ortiz, José J; Farkas, Vladimir; Pedersen, Henriette L; Willats, William G T; Knox, J Paul

2008-05-22

Molecular probes are required to detect cell wall polymers in-situ to aid understanding of their cell biology and several studies have shown that cell wall epitopes have restricted occurrences across sections of plant organs indicating that cell wall structure is highly developmentally regulated. Xyloglucan is the major hemicellulose or cross-linking glycan of the primary cell walls of dicotyledons although little is known of its occurrence or functions in relation to cell development and cell wall microstructure. Using a neoglycoprotein approach, in which a XXXG heptasaccharide of tamarind seed xyloglucan was coupled to BSA to produce an immunogen, we have generated a rat monoclonal antibody (designated LM15) to the XXXG structural motif of xyloglucans. The specificity of LM15 has been confirmed by the analysis of LM15 binding using glycan microarrays and oligosaccharide hapten inhibition of binding studies. The use of LM15 for the analysis of xyloglucan in the cell walls of tamarind and nasturtium seeds, in which xyloglucan occurs as a storage polysaccharide, indicated that the LM15 xyloglucan epitope occurs throughout the thickened cell walls of the tamarind seed and in the outer regions, adjacent to middle lamellae, of the thickened cell walls of the nasturtium seed. Immunofluorescence analysis of LM15 binding to sections of tobacco and pea stem internodes indicated that the xyloglucan epitope was restricted to a few cell types in these organs. Enzymatic removal of pectic homogalacturonan from equivalent sections resulted in the abundant detection of distinct patterns of the LM15 xyloglucan epitope across these organs and a diversity of occurrences in relation to the cell wall microstructure of a range of cell types. These observations support ideas that xyloglucan is associated with pectin in plant cell walls. They also indicate that documented patterns of cell wall epitopes in relation to cell development and cell differentiation may need to be re-considered in relation to the potential masking of cell wall epitopes by other cell wall components.

An Arabidopsis Gene Regulatory Network for Secondary Cell Wall Synthesis

PubMed Central

Taylor-Teeples, M; Lin, L; de Lucas, M; Turco, G; Toal, TW; Gaudinier, A; Young, NF; Trabucco, GM; Veling, MT; Lamothe, R; Handakumbura, PP; Xiong, G; Wang, C; Corwin, J; Tsoukalas, A; Zhang, L; Ware, D; Pauly, M; Kliebenstein, DJ; Dehesh, K; Tagkopoulos, I; Breton, G; Pruneda-Paz, JL; Ahnert, SE; Kay, SA; Hazen, SP; Brady, SM

2014-01-01

Summary The plant cell wall is an important factor for determining cell shape, function and response to the environment. Secondary cell walls, such as those found in xylem, are composed of cellulose, hemicelluloses and lignin and account for the bulk of plant biomass. The coordination between transcriptional regulation of synthesis for each polymer is complex and vital to cell function. A regulatory hierarchy of developmental switches has been proposed, although the full complement of regulators remains unknown. Here, we present a protein-DNA network between Arabidopsis transcription factors and secondary cell wall metabolic genes with gene expression regulated by a series of feed-forward loops. This model allowed us to develop and validate new hypotheses about secondary wall gene regulation under abiotic stress. Distinct stresses are able to perturb targeted genes to potentially promote functional adaptation. These interactions will serve as a foundation for understanding the regulation of a complex, integral plant component. PMID:25533953

Changes in levels of cell wall constituents in wheat seedlings grown under continuous hypergravity conditions

NASA Astrophysics Data System (ADS)

Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

Effects of continuous hypergravity stimuli on the amounts and composition of cell wall constituents were investigated in wheat shoots. Hypergravity (300 g) treatment for three days after germination increased the net amount of cell wall polysaccharides such as hemicellulose and cellulose, but reduced the shoot elongation. As a result, the amount of cell wall polysaccharides per unit length of shoot increased under hypergravity. The hemicellulose fraction contained polysaccharides in the middle and low molecular mass range (5 kDa-1 MDa) and increased in response to hypergravity. Also, the amounts of arabinose (Ara) and xylose (Xyl), the major sugar components of the hemicellulose fraction, increased under hypergravity conditions. In addition to wall polysaccharides, hypergravity increased the amounts of cell wall-bound phenolic acids, such as ferulic acid (FA) and diferulic acid (DFA). Furthermore, the activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) was enhanced under hypergravity conditions. These results suggest that continuous hypergravity stimulates the synthesis of cell wall constituents, especially hemicellulosic arabinoxylans and cell wall-bound FA and DFA in wheat shoots. The increased PAL activity may promote the formation of FA and DFA. These changes in cell wall architecture may be involved in making rigid and tough cell walls under hypergravity conditions and thereby contribute to the ability of plant to sustain their structures against gravitational stimuli.

Investigation of cell wall composition related to stem lodging resistance in wheat (Triticum aestivum L.) by FTIR spectroscopy.

PubMed

Wang, Jian; Zhu, Jinmao; Huang, RuZhu; Yang, YuSheng

2012-07-01

We explored the rapid qualitative analysis of wheat cultivars with good lodging resistances by Fourier transform infrared resonance (FTIR) spectroscopy and multivariate statistical analysis. FTIR imaging showing that wheat stem cell walls were mainly composed of cellulose, pectin, protein, and lignin. Principal components analysis (PCA) was used to eliminate multicollinearity among multiple peak absorptions. PCA revealed the developmental internodes of wheat stems could be distributed from low to high along the load of the second principal component, which was consistent with the corresponding bands of cellulose in the FTIR spectra of the cell walls. Furthermore, four distinct stem populations could also be identified by spectral features related to their corresponding mechanical properties via PCA and cluster analysis. Histochemical staining of four types of wheat stems with various abilities to resist lodging revealed that cellulose contributed more than lignin to the ability to resist lodging. These results strongly suggested that the main cell wall component responsible for these differences was cellulose. Therefore, the combination of multivariate analysis and FTIR could rapidly screen wheat cultivars with good lodging resistance. Furthermore, the application of these methods to a much wider range of cultivars of unknown mechanical properties promises to be of interest.

Detection of Cell Wall Chemical Variation in Zea Mays Mutants Using Near-Infrared Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buyck, N.; Thomas, S.

Corn stover is regarded as the prime candidate feedstock material for commercial biomass conversion in the United States. Variations in chemical composition of Zea mays cell walls can affect biomass conversion process yields and economics. Mutant lines were constructed by activating a Mu transposon system. The cell wall chemical composition of 48 mutant families was characterized using near-infrared (NIR) spectroscopy. NIR data were analyzed using a multivariate statistical analysis technique called Principal Component Analysis (PCA). PCA of the NIR data from 349 maize leaf samples reveals 57 individuals as outliers on one or more of six Principal Components (PCs) atmore » the 95% confidence interval. Of these, 19 individuals from 16 families are outliers on either PC3 (9% of the variation) or PC6 (1% of the variation), the two PCs that contain information about cell wall polymers. Those individuals for which altered cell wall chemistry is confirmed with wet chemical analysis will then be subjected to fermentation analysis to determine whether or not biomass conversion process kinetics, yields and/or economics are significantly affected. Those mutants that provide indications for a decrease in process cost will be pursued further to identify the gene(s) responsible for the observed changes in cell wall composition and associated changes in process economics. These genes will eventually be incorporated into maize breeding programs directed at the development of a truly dual use crop.« less

A Synthetic Glycan Microarray Enables Epitope Mapping of Plant Cell Wall Glycan-Directed Antibodies.

PubMed

Ruprecht, Colin; Bartetzko, Max P; Senf, Deborah; Dallabernadina, Pietro; Boos, Irene; Andersen, Mathias C F; Kotake, Toshihisa; Knox, J Paul; Hahn, Michael G; Clausen, Mads H; Pfrengle, Fabian

2017-11-01

In the last three decades, more than 200 monoclonal antibodies have been raised against most classes of plant cell wall polysaccharides by different laboratories worldwide. These antibodies are widely used to identify differences in plant cell wall components in mutants, organ and tissue types, and developmental stages. Despite their importance and broad use, the precise binding epitope has been determined for only a few of these antibodies. Here, we use a plant glycan microarray equipped with 88 synthetic oligosaccharides to comprehensively map the epitopes of plant cell wall glycan-directed antibodies. Our results reveal the binding epitopes for 78 arabinogalactan-, rhamnogalacturonan-, xylan-, and xyloglucan-directed antibodies. We demonstrate that, with knowledge of the exact epitopes recognized by individual antibodies, specific glycosyl hydrolases can be implemented into immunological cell wall analyses, providing a framework to obtain structural information on plant cell wall glycans with unprecedented molecular precision. © 2017 American Society of Plant Biologists. All Rights Reserved.

Secretory production of cell wall components by Saccharomyces cerevisiae protoplasts in static liquid culture.

PubMed

Aoyagi, Hideki; Ishizaka, Mikiko; Tanaka, Hideo

2012-04-01

When protoplasts of Saccharomyces cerevisiae T7 and IFO 0309 are cultured in a static liquid culture at 2.5 × 10(6) protoplasts/ml, cell wall regeneration does not occur and cell wall components (CWC) are released into the culture broth. By using a specialized fluorometer, the concentrations of CWC could be measured on the basis of the fluorescence intensity of the CWC after staining with Fluostain I. The inoculum concentration, pH, and osmotic pressure of the medium were important factors for the production of CWC in culture. Under optimal culture conditions, S. cerevisiae T7 protoplasts produced 0.91 mg/ml CWC after 24 h. The CWC induced the tumor necrosis factor-α production about 1.3 times higher than that of the commercially available β-1,3/1,6-glucan from baker's yeast cells.

Changes in cell wall polysaccharide composition, gene transcription and alternative splicing in germinating barley embryos.

PubMed

Zhang, Qisen; Zhang, Xiaoqi; Pettolino, Filomena; Zhou, Gaofeng; Li, Chengdao

2016-02-01

Barley (Hordeum vulgare L.) seed germination initiates many important biological processes such as DNA, membrane and mitochondrial repairs. However, little is known on cell wall modifications in germinating embryos. We have investigated cell wall polysaccharide composition change, gene transcription and alternative splicing events in four barley varieties at 24h and 48 h germination. Cell wall components in germinating barley embryos changed rapidly, with increases in cellulose and (1,3)(1,4)-β-D-glucan (20-100%) within 24h, but decreases in heteroxylan and arabinan (3-50%). There were also significant changes in the levels of type I arabinogalactans and heteromannans. Alternative splicing played very important roles in cell wall modifications. At least 22 cell wall transcripts were detected to undergo either alternative 3' splicing, alternative 5' splicing or intron retention type of alternative splicing. These genes coded enzymes catalyzing synthesis and degradation of cellulose, heteroxylan, (1,3)(1,4)-β-D-glucan and other cell wall polymers. Furthermore, transcriptional regulation also played very important roles in cell wall modifications. Transcript levels of primary wall cellulase synthase, heteroxylan synthesizing and nucleotide sugar inter-conversion genes were very high in germinating embryos. At least 50 cell wall genes changed transcript levels significantly. Expression patterns of many cell wall genes coincided with changes in polysaccharide composition. Our data showed that cell wall polysaccharide metabolism was very active in germinating barley embryos, which was regulated at both transcriptional and post-transcriptional levels. Copyright © 2015 Elsevier GmbH. All rights reserved.

A Structurally Specialized Uniform Wall Layer is Essential for Constructing Wall Ingrowth Papillae in Transfer Cells

PubMed Central

Xia, Xue; Zhang, Hui-Ming; Offler, Christina E.; Patrick, John W.

2017-01-01

Transfer cells are characterized by wall labyrinths with either a flange or reticulate architecture. A literature survey established that reticulate wall ingrowth papillae ubiquitously arise from a modified component of their wall labyrinth, termed the uniform wall layer; a structure absent from flange transfer cells. This finding sparked an investigation of the deposition characteristics and role of the uniform wall layer using a Vicia faba cotyledon culture system. On transfer of cotyledons to culture, their adaxial epidermal cells spontaneously trans-differentiate to a reticulate architecture comparable to their abaxial epidermal transfer cell counterparts formed in planta. Uniform wall layer construction commenced once adaxial epidermal cell expansion had ceased to overlay the original outer periclinal wall on its inner surface. In contrast to the dense ring-like lattice of cellulose microfibrils in the original primary wall, the uniform wall layer was characterized by a sparsely dispersed array of linear cellulose microfibrils. A re-modeled cortical microtubule array exerted no influence on uniform wall layer formation or on its cellulose microfibril organization. Surprisingly, formation of the uniform wall layer was not dependent upon depositing a cellulose scaffold. In contrast, uniform wall cellulose microfibrils were essential precursors for constructing wall ingrowth papillae. On converging to form wall ingrowth papillae, the cellulose microfibril diameters increased 3-fold. This event correlated with up-regulated differential, and transfer-cell specific, expression of VfCesA3B while transcript levels of other cellulose biosynthetic-related genes linked with primary wall construction were substantially down-regulated. PMID:29259611

A Structurally Specialized Uniform Wall Layer is Essential for Constructing Wall Ingrowth Papillae in Transfer Cells.

PubMed

Xia, Xue; Zhang, Hui-Ming; Offler, Christina E; Patrick, John W

2017-01-01

Transfer cells are characterized by wall labyrinths with either a flange or reticulate architecture. A literature survey established that reticulate wall ingrowth papillae ubiquitously arise from a modified component of their wall labyrinth, termed the uniform wall layer; a structure absent from flange transfer cells. This finding sparked an investigation of the deposition characteristics and role of the uniform wall layer using a Vicia faba cotyledon culture system. On transfer of cotyledons to culture, their adaxial epidermal cells spontaneously trans -differentiate to a reticulate architecture comparable to their abaxial epidermal transfer cell counterparts formed in planta . Uniform wall layer construction commenced once adaxial epidermal cell expansion had ceased to overlay the original outer periclinal wall on its inner surface. In contrast to the dense ring-like lattice of cellulose microfibrils in the original primary wall, the uniform wall layer was characterized by a sparsely dispersed array of linear cellulose microfibrils. A re-modeled cortical microtubule array exerted no influence on uniform wall layer formation or on its cellulose microfibril organization. Surprisingly, formation of the uniform wall layer was not dependent upon depositing a cellulose scaffold. In contrast, uniform wall cellulose microfibrils were essential precursors for constructing wall ingrowth papillae. On converging to form wall ingrowth papillae, the cellulose microfibril diameters increased 3-fold. This event correlated with up-regulated differential, and transfer-cell specific, expression of VfCesA3B while transcript levels of other cellulose biosynthetic-related genes linked with primary wall construction were substantially down-regulated.

Mutational analysis of the glycosylphosphatidylinositol (GPI) anchor pathway demonstrates that GPI-anchored proteins are required for cell wall biogenesis and normal hyphal growth in Neurospora crassa.

PubMed

Bowman, Shaun M; Piwowar, Amy; Al Dabbous, Mash'el; Vierula, John; Free, Stephen J

2006-03-01

Using mutational and proteomic approaches, we have demonstrated the importance of the glycosylphosphatidylinositol (GPI) anchor pathway for cell wall synthesis and integrity and for the overall morphology of the filamentous fungus Neurospora crassa. Mutants affected in the gpig-1, gpip-1, gpip-2, gpip-3, and gpit-1 genes, which encode components of the N. crassa GPI anchor biosynthetic pathway, have been characterized. GPI anchor mutants exhibit colonial morphologies, significantly reduced rates of growth, altered hyphal growth patterns, considerable cellular lysis, and an abnormal "cell-within-a-cell" phenotype. The mutants are deficient in the production of GPI-anchored proteins, verifying the requirement of each altered gene for the process of GPI-anchoring. The mutant cell walls are abnormally weak, contain reduced amounts of protein, and have an altered carbohydrate composition. The mutant cell walls lack a number of GPI-anchored proteins, putatively involved in cell wall biogenesis and remodeling. From these studies, we conclude that the GPI anchor pathway is critical for proper cell wall structure and function in N. crassa.

Shading Contributes to the Reduction of Stem Mechanical Strength by Decreasing Cell Wall Synthesis in Japonica Rice (Oryza sativa L.).

PubMed

Wu, Longmei; Zhang, Wujun; Ding, Yanfeng; Zhang, Jianwei; Cambula, Elidio D; Weng, Fei; Liu, Zhenghui; Ding, Chengqiang; Tang, She; Chen, Lin; Wang, Shaohua; Li, Ganghua

2017-01-01

Low solar radiation caused by industrial development and solar dimming has become a limitation in crop production in China. It is widely accepted that low solar radiation influences many aspects of plant development, including slender, weak stems and susceptibility to lodging. However, the underlying mechanisms are not well understood. To clarify how low solar radiation affects stem mechanical strength formation and lodging resistance, the japonica rice cultivars Wuyunjing23 (lodging-resistant) and W3668 (lodging-susceptible) were grown under field conditions with normal light (Control) and shading (the incident light was reduced by 60%) with a black nylon net. The yield and yield components, plant morphological characteristics, the stem mechanical strength, cell wall components, culm microstructure, gene expression correlated with cellulose and lignin biosynthesis were measured. The results showed that shading significantly reduced grain yield attributed to reduction of spikelets per panicles and grain weight. The stem-breaking strength decreased significantly under shading treatment; consequently, resulting in higher lodging index in rice plant in both varieties, as revealed by decreased by culm diameter, culm wall thickness and increased plant height, gravity center height. Compared with control, cell wall components including non-structural carbohydrate, sucrose, cellulose, and lignin reduced quite higher. With histochemical straining, shading largely reduced lignin deposition in the sclerenchyma cells and vascular bundle cells compared with control, and decreased cellulose deposition in the parenchyma cells of culm tissue in both Wuyunjing23 and W3668. And under shading condition, gene expression involved in secondary cell wall synthesis, OsPAL, OsCOMT, OsCCoAOMT, OsCCR , and OsCAD2 , and primary cell wall synthesis, OsCesA1, OsCesA3 , and OsCesA8 were decreased significantly. These results suggest that gene expression involved in the reduction of lignin and cellulose in both sclerenchyma and parenchyma cells, which attribute to lignin and cellulose in culm tissue and weak mechanical tissue, consequently, result in poor stem strength and higher lodging risks. Highlights : (1) Shading decreases the stem mechanical strength of japonica rice by decreasing non-structural carbohydrate, sucrose, lignin, and cellulose accumulation in culms. (2) The decrease of carbon source under shading condition is the cause for the lower lignin and cellulose accumulation in culm. (3) The expression of genes involved in lignin and primarily cell wall cellulose biosynthesis ( OsCesA1, OsCesA3 , and OsCesA8 ) at the stem formation stage are down-regulated under shading condition, inducing defective cell wall development and poor lodging resistance.

Arabinogalactan Proteins Accumulate in the Cell Walls of Searching Hyphae of the Stem Parasitic Plants, Cuscuta campestris and Cuscuta japonica.

PubMed

Hozumi, Akitaka; Bera, Subhankar; Fujiwara, Daiki; Obayashi, Takeshi; Yokoyama, Ryusuke; Nishitani, Kazuhiko; Aoki, Koh

2017-11-01

Stem parasitic plants (Cuscuta spp.) develop a specialized organ called a haustorium to penetrate their hosts' stem tissues. To reach the vascular tissues of the host plant, the haustorium needs to overcome the physical barrier of the cell wall, and the parasite-host interaction via the cell wall is a critical process. However, the cell wall components responsible for the establishment of parasitic connections have not yet been identified. In this study, we investigated the spatial distribution patterns of cell wall components at a parasitic interface using parasite-host complexes of Cuscuta campestris-Arabidopsis thaliana and Cuscuta japonica-Glycine max. We focused on arabinogalactan proteins (AGPs), because AGPs accumulate in the cell walls of searching hyphae of both C. campestris and C. japonica. We found more AGPs in elongated haustoria than in pre haustoria, indicating that AGP accumulation is developmentally regulated. Using in situ hybridization, we identified five genes in C. campestris that encode hyphal-expressed AGPs that belong to the fasciclin-like AGP (FLA) family, which were named CcFLA genes. Three of the five CcFLA genes were expressed in the holdfast, which develops on the Cuscuta stem epidermis at the attachment site for the host's stem epidermis. Our results suggest that AGPs are involved in hyphal elongation and adhesion to host cells, and in the adhesion between the epidermal tissues of Cuscuta and its host. © The Author 2017. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

A new picture of cell wall protein dynamics in elongating cells of Arabidopsis thaliana: Confirmed actors and newcomers

PubMed Central

Irshad, Muhammad; Canut, Hervé; Borderies, Gisèle; Pont-Lezica, Rafael; Jamet, Elisabeth

2008-01-01

Background Cell elongation in plants requires addition and re-arrangements of cell wall components. Even if some protein families have been shown to play roles in these events, a global picture of proteins present in cell walls of elongating cells is still missing. A proteomic study was performed on etiolated hypocotyls of Arabidopsis used as model of cells undergoing elongation followed by growth arrest within a short time. Results Two developmental stages (active growth and after growth arrest) were compared. A new strategy consisting of high performance cation exchange chromatography and mono-dimensional electrophoresis was established for separation of cell wall proteins. This work allowed identification of 137 predicted secreted proteins, among which 51 had not been identified previously. Apart from expected proteins known to be involved in cell wall extension such as xyloglucan endotransglucosylase-hydrolases, expansins, polygalacturonases, pectin methylesterases and peroxidases, new proteins were identified such as proteases, proteins related to lipid metabolism and proteins of unknown function. Conclusion This work highlights the CWP dynamics that takes place between the two developmental stages. The presence of proteins known to be related to cell wall extension after growth arrest showed that these proteins may play other roles in cell walls. Finally, putative regulatory mechanisms of protein biological activity are discussed from this global view of cell wall proteins. PMID:18796151

Broad diversity and newly cultured bacterial isolates from enrichment of pig feces on complex polysaccharides

USDA-ARS?s Scientific Manuscript database

Microbial fermentation of plant cell wall components to short chain fatty acids in the large intestine provides energy to both humans and pigs. To better understand plant cell wall fermentation in the pig and human intestine, we isolated cellulose, xylan, and pectin fermenting bacteria from pig and ...

Identifying new lignin bioengineering targets for improving biomass and forage utilization: a review of biomimetic studies with maize cell walls

USDA-ARS?s Scientific Manuscript database

Bioengineering of lignin to contain atypical components derived from other metabolic pathways is increasingly being pursued to custom design lignified cell walls that are more readily pretreated and saccharified for biofuel production or easily digested by livestock. Because plants produce such a di...

Chapter 3 Cell Wall Chemistry

Treesearch

Roger M. Rowell; Roger Pettersen; Mandla A. Tshabalala

2012-01-01

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 dry weight basis, all wood cell walls consist mainly of sugar-based polymers (carbohydrates, 65-75%) that are...

S-layers: principles and applications

PubMed Central

Sleytr, Uwe B; Schuster, Bernhard; Egelseer, Eva-Maria; Pum, Dietmar

2014-01-01

Monomolecular arrays of protein or glycoprotein subunits forming surface layers (S-layers) are one of the most commonly observed prokaryotic cell envelope components. S-layers are generally the most abundantly expressed proteins, have been observed in species of nearly every taxonomical group of walled bacteria, and represent an almost universal feature of archaeal envelopes. The isoporous lattices completely covering the cell surface provide organisms with various selection advantages including functioning as protective coats, molecular sieves and ion traps, as structures involved in surface recognition and cell adhesion, and as antifouling layers. S-layers are also identified to contribute to virulence when present as a structural component of pathogens. In Archaea, most of which possess S-layers as exclusive wall component, they are involved in determining cell shape and cell division. Studies on structure, chemistry, genetics, assembly, function, and evolutionary relationship of S-layers revealed considerable application potential in (nano)biotechnology, biomimetics, biomedicine, and synthetic biology. PMID:24483139

MmpL Genes Are Associated with Mycolic Acid Metabolism in Mycobacteria and Corynebacteria

PubMed Central

Varela, Cristian; Rittmann, Doris; Singh, Albel; Krumbach, Karin; Bhatt, Kiranmai; Eggeling, Lothar; Besra, Gurdyal S.; Bhatt, Apoorva

2012-01-01

Summary Mycolic acids are vital components of the cell wall of the tubercle bacillus Mycobacterium tuberculosis and are required for viability and virulence. While mycolic acid biosynthesis is studied extensively, components involved in mycolate transport remain unidentified. We investigated the role of large membrane proteins encoded by mmpL genes in mycolic acid transport in mycobacteria and the related corynebacteria. MmpL3 was found to be essential in mycobacteria and conditional depletion of MmpL3 in Mycobacterium smegmatis resulted in loss of cell wall mycolylation, and of the cell wall-associated glycolipid, trehalose dimycolate. In parallel, an accumulation of trehalose monomycolate (TMM) was observed, suggesting that mycolic acids were transported as TMM. In contrast to mycobacteria, we found redundancy in the role of two mmpL genes, in Corynebacterium glutamicum; a complete loss of trehalose-associated and cell wall bound corynomycolates was observed in an NCgl0228-NCgl2769 double mutant, but not in individual single mutants. Our studies highlight the role of mmpL genes in mycolic acid metabolism and identify potential new targets for anti-TB drug development. PMID:22520756

Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra1[W][OA

PubMed Central

Hansen, Steen Laugesen; Ray, Peter Martin; Karlsson, Anders Ola; Jørgensen, Bodil; Borkhardt, Bernhard; Petersen, Bent Larsen; Ulvskov, Peter

2011-01-01

Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild type. This may be due to the plant’s ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply a method, determination of relaxation spectra, which probes, and can separate, the viscoelastic properties of different cell wall components (i.e. those properties that depend on the elastic behavior of load-bearing wall polymers combined with viscous interactions between them). A computer program, BayesRelax, that deduces relaxation spectra from appropriate rheological measurements is presented and made accessible through a Web interface. BayesRelax models the cell wall as a continuum of relaxing elements, and the ability of the method to resolve small differences in cell wall mechanical properties is demonstrated using tuber tissue from wild-type and transgenic potatoes (Solanum tuberosum) that differ in rhamnogalacturonan I side chain structure. PMID:21075961

Cell wall assembly in fucus zygotes: I. Characterization of the polysaccharide components.

PubMed

Quatrano, R S; Stevens, P T

1976-08-01

Fertilization triggers the assembly of a cell wall around the egg cell of three brown algae, Fucus vesiculosus, F. distichus, and F. inflatus. 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 (F(1)) 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 (F(2)) which is electrophoretically distinct from F(1). F(2) 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 (0.33-0.55) or its block distribution (MG, 54%; GG, 30%; MM, 16%). From 6 to 24 hours of embryo development, the proportion of the major polysaccharide components found in purified walls is stable. Alginic acid is the major polymer and comprises about 60% of the total wall, while cellulose and the fucans each make-up about 20% of the remainder. During the extracellular assembly of this wall, the intracellular levels of the storage glucan laminaran decreases. A membrane-bound beta-1, 3-exoglucanase is found in young zygotes which degrades laminaran to glucose. It is postulated that hydrolysis of laminaran by this glucanase accounts, at least in part, for glucose availability for wall biosynthesis and the increase in respiration triggered by fertilization. The properties and function of alginic acid, the fucans, and cellulose are discussed in relation to changes in wall structure and function during development.

The structure of a β-(1→3)-d-glucan from yeast cell walls

PubMed Central

Manners, David J.; Masson, Alan J.; Patterson, James C.

1973-01-01

Yeast glucan as normally prepared by various treatments of yeast (Saccharomyces cerevisiae) cell walls to remove mannan and glycogen is still heterogeneous. The major component (about 85%) is a branched β-(1→3)-glucan of high molecular weight (about 240000) containing 3% of β-(1→6)-glucosidic interchain linkages. The minor component is a branched β-(1→6)-glucan. A comparison of our results with those of other workers suggests that different glucan preparations may differ in the degree of heterogeneity and that the major β-(1→3)-glucan component may vary considerably in degree of branching. PMID:4359920

Effect of growth conditions on production of rhamnose-containing cell wall and capsular polysaccharides by strains of Lactobacillus casei subsp. rhamnosus.

PubMed

Wicken, A J; Ayres, A; Campbell, L K; Knox, K W

1983-01-01

Strains of Lactobacillus casei subsp. rhamnosus possessing two cell wall polysaccharides, a hexosamine-containing H-polysaccharide and a rhamnose-containing R-polysaccharide, were examined for the effect of growth conditions on the production of these two components. In strain NCTC 6375, R- and H-polysaccharides accounted for an estimated 44 and 20%, respectively, of the cell wall for organisms grown in batch culture with glucose as the carbohydrate source. Growth on fructose-containing media reduced the amount of R-polysaccharide by approximately 50% without affecting the amount of H-polysaccharide. Subculture of fructose-grown organisms in glucose restored the original proportions of the two polysaccharides. Galactose- and sucrose-grown cells behaved similarly to glucose-grown cells with respect to polysaccharide production, whereas growth in rhamnose or ribose showed values close to those for fructose-grown cells. Continuous culture of strain NCTC 6375 for more than 100 generations showed a gradual and irreversible reduction of the R-polysaccharide to less than 5% of the cell wall and an increase of the H-polysaccharide to 40% of the cell wall. Other type culture strains of L. casei subsp. rhamnosus, NCIB 7473 and ATCC 7469, behaved similarly in batch and continuous culture. In contrast, strains of L. casei subsp. rhamnosus isolated at the Institute of Dental Research showed phenotypic stability with respect to the relative proportions of R- and H-polysaccharides in both batch and continuous culture. Changes in polysaccharide composition of type culture strains were also mirrored in changes in the immunogenicity of the two components and resistance to the rate of enzymic lysis of whole organisms. For L. casei subsp. rhamnosus strain NCTC 10302 the R-polysaccharide is present entirely as capsular material. The amount of R-polysaccharide produced was also markedly dependent on the carbohydrate component of the medium in batch culture and both dilution rate and nature of the limiting carbohydrate in continuous culture, varying over a 10-fold range, whereas the cell wall H-polysaccharide remained constant.

Effect of growth conditions on production of rhamnose-containing cell wall and capsular polysaccharides by strains of Lactobacillus casei subsp. rhamnosus.

PubMed Central

Wicken, A J; Ayres, A; Campbell, L K; Knox, K W

1983-01-01

Strains of Lactobacillus casei subsp. rhamnosus possessing two cell wall polysaccharides, a hexosamine-containing H-polysaccharide and a rhamnose-containing R-polysaccharide, were examined for the effect of growth conditions on the production of these two components. In strain NCTC 6375, R- and H-polysaccharides accounted for an estimated 44 and 20%, respectively, of the cell wall for organisms grown in batch culture with glucose as the carbohydrate source. Growth on fructose-containing media reduced the amount of R-polysaccharide by approximately 50% without affecting the amount of H-polysaccharide. Subculture of fructose-grown organisms in glucose restored the original proportions of the two polysaccharides. Galactose- and sucrose-grown cells behaved similarly to glucose-grown cells with respect to polysaccharide production, whereas growth in rhamnose or ribose showed values close to those for fructose-grown cells. Continuous culture of strain NCTC 6375 for more than 100 generations showed a gradual and irreversible reduction of the R-polysaccharide to less than 5% of the cell wall and an increase of the H-polysaccharide to 40% of the cell wall. Other type culture strains of L. casei subsp. rhamnosus, NCIB 7473 and ATCC 7469, behaved similarly in batch and continuous culture. In contrast, strains of L. casei subsp. rhamnosus isolated at the Institute of Dental Research showed phenotypic stability with respect to the relative proportions of R- and H-polysaccharides in both batch and continuous culture. Changes in polysaccharide composition of type culture strains were also mirrored in changes in the immunogenicity of the two components and resistance to the rate of enzymic lysis of whole organisms. For L. casei subsp. rhamnosus strain NCTC 10302 the R-polysaccharide is present entirely as capsular material. The amount of R-polysaccharide produced was also markedly dependent on the carbohydrate component of the medium in batch culture and both dilution rate and nature of the limiting carbohydrate in continuous culture, varying over a 10-fold range, whereas the cell wall H-polysaccharide remained constant. PMID:6401290

Differential protection by cell wall components of Lactobacillus amylovorus DSM 16698Tagainst alterations of membrane barrier and NF-kB activation induced by enterotoxigenic F4+ Escherichia coli on intestinal cells.

PubMed

Roselli, Marianna; Finamore, Alberto; Hynönen, Ulla; Palva, Airi; Mengheri, Elena

2016-09-29

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. amylovorus DSM 16698 T is able to reduce the enterotoxigenic F4 + Escherichia coli (ETEC) adhesion and prevent the pathogen-induced membrane barrier disruption through the regulation of IL-10 and IL-8 expression in intestinal cells. We have also demonstrated that L. amylovorus DSM 16698 T protects host cells through the inhibition of NF-kB signaling. In the present study, we investigated the role of L. amylovorus DSM 16698 T cell wall components in the protection against F4 + ETEC infection using the intestinal Caco-2 cell line. Purified cell wall fragments (CWF) from L. amylovorus DSM 16698 T were used either as such (uncoated, U-CWF) or coated with S-layer proteins (S-CWF). Differentiated Caco-2/TC7 cells on Transwell filters were infected with F4 + ETEC, treated with S-CWF or U-CWF, co-treated with S-CWF or U-CWF and F4 + ETEC for 2.5 h, or pre-treated with S-CWF or U-CWF for 1 h before F4 + ETEC addition. Tight junction (TJ) and adherens junction (AJ) proteins were analyzed by immunofluorescence and Western blot. Membrane permeability was determined by phenol red passage. Phosphorylated p65-NF-kB was measured by Western blot. We showed that both the pre-treatment with S-CWF and the co- treatment of S-CWF with the pathogen protected the cells from F4 + ETEC induced TJ and AJ injury, increased membrane permeability and activation of NF-kB expression. Moreover, the U-CWF pre-treatment, but not the co-treatment with F4 + ETEC, inhibited membrane damage and prevented NF-kB activation. The results indicate that the various components of L. amylovorus DSM 16698 T cell wall may counteract the damage caused by F4 + ETEC through different mechanisms. S-layer proteins are essential for maintaining membrane barrier function and for mounting an anti-inflammatory response against F4 + ETEC infection. U-CWF are not able to defend the cells when they are infected with F4 + ETEC but may activate protective mechanisms before pathogen infection.

17. Interior view of Test Cell 8 (oxidizer) in Components ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. Interior view of Test Cell 8 (oxidizer) in Components Test Laboratory (T-27), showing west and north walls. Photograph shows upgraded instrumentation, piping, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

14. Interior view of Test Cell 10 (environmental) in Components ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Interior view of Test Cell 10 (environmental) in Components Test Laboratory (T-27), showing east and south walls. Photograph shows upgraded instrumentation, piping, and technological modifications installed in 1997-99 to accommodate component testing requirements for the Atlas V missile. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

RNA-Seq analysis of global transcriptomic changes suggests a roles for the MAPK pathway and carbon metabolism in cell wall maintenance in a Saccharomyces cerevisiae FKS1 mutant.

PubMed

Huang, Cong; Zhao, Fengguang; Lin, Ying; Zheng, Suiping; Liang, Shuli; Han, Shuangyan

2018-06-07

FKS1 encodes a β-1,3-glucan synthase, which is a key player in cell wall assembly in Saccharomyces cerevisiae. Here we analyzed the global transcriptomic changes in the FKS1 mutant to establish a correlation between the changes in the cell wall of the FKS1 mutant and the molecular mechanism of cell wall maintenance. These transcriptomic profiles showed that there are 1151 differentially expressed genes (DEGs) in the FKS1 mutant. Through KEGG pathway analysis of the DEGs, the MAPK pathway and seven pathways involved in carbon metabolism were significantly enriched. We found that the MAPK pathway is activated for FKS1 mutant survival and the synthesis of cell wall components are reinforced in the FKS1 mutant. Our results confirm that the FKS1 mutant has a β-1,3-glucan defect that affects the cell wall and partly elucidate the molecular mechanism responsible for cell wall synthesis. Our greater understanding of these mechanisms helps to explain how the FKS1 mutant survives, has useful implications for the study of similar pathways in other fungi, and increases the theoretical foundation for the regulation of the cell wall in S. cerevisiae. Copyright © 2018 Elsevier Inc. All rights reserved.

How cell wall complexity influences saccharification efficiency in Miscanthus sinensis

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Souza, Amanda P.; Kamei, Claire L. Alvim; Torres, Andres F.

The production of bioenergy from grasses has been developing quickly during the last decade, with Miscanthus being among the most important choices for production of bioethanol. However, one of the key barriers to producing bioethanol is the lack of information about cell wall structure. Cell walls are thought to display compositional differences that lead to emergence of a very high level of complexity, resulting in great diversity in cell wall architectures. In this work, a set of different techniques was used to access the complexity of cell walls of different genotypes of Miscanthus sinensis in order to understand how theymore » interfere with saccharification efficiency. Three genotypes of M. sinensis displaying different patterns of correlation between lignin content and saccharification efficiency were subjected to cell wall analysis by quantitative/qualitative analytical techniques such as monosaccharide composition, oligosaccharide profiling, and glycome profiling. When saccharification efficiency was correlated negatively with lignin, the structural features of arabinoxylan and xyloglucan were found to contribute positively to hydrolysis. In the absence of such correlation, different types of pectins, and some mannans contributed to saccharification efficiency. In conclusion, different genotypes of M. sinensis were shown to display distinct interactions among their cell wall components, which seem to influence cell wall hydrolysis.« less

How cell wall complexity influences saccharification efficiency in Miscanthus sinensis

DOE PAGES

De Souza, Amanda P.; Kamei, Claire L. Alvim; Torres, Andres F.; ...

2015-04-23

The production of bioenergy from grasses has been developing quickly during the last decade, with Miscanthus being among the most important choices for production of bioethanol. However, one of the key barriers to producing bioethanol is the lack of information about cell wall structure. Cell walls are thought to display compositional differences that lead to emergence of a very high level of complexity, resulting in great diversity in cell wall architectures. In this work, a set of different techniques was used to access the complexity of cell walls of different genotypes of Miscanthus sinensis in order to understand how theymore » interfere with saccharification efficiency. Three genotypes of M. sinensis displaying different patterns of correlation between lignin content and saccharification efficiency were subjected to cell wall analysis by quantitative/qualitative analytical techniques such as monosaccharide composition, oligosaccharide profiling, and glycome profiling. When saccharification efficiency was correlated negatively with lignin, the structural features of arabinoxylan and xyloglucan were found to contribute positively to hydrolysis. In the absence of such correlation, different types of pectins, and some mannans contributed to saccharification efficiency. In conclusion, different genotypes of M. sinensis were shown to display distinct interactions among their cell wall components, which seem to influence cell wall hydrolysis.« less

Silica distinctively affects cell wall features and lignocellulosic saccharification with large enhancement on biomass production in rice.

PubMed

Zhang, Jing; Zou, Weihua; Li, Ying; Feng, Yongqing; Zhang, Hui; Wu, Zhiliang; Tu, Yuanyuan; Wang, Yanting; Cai, Xiwen; Peng, Liangcai

2015-10-01

Rice is a typical silicon-accumulating crop with enormous biomass residues for biofuels. Silica is a cell wall component, but its effect on the plant cell wall and biomass production remains largely unknown. In this study, a systems biology approach was performed using 42 distinct rice cell wall mutants. We found that silica levels are significantly positively correlated with three major wall polymers, indicating that silica is associated with the cell wall network. Silicon-supplied hydroculture analysis demonstrated that silica distinctively affects cell wall composition and major wall polymer features, including cellulose crystallinity (CrI), arabinose substitution degree (reverse Xyl/Ara) of xylans, and sinapyl alcohol (S) proportion in three typical rice mutants. Notably, the silicon supplement exhibited dual effects on biomass enzymatic digestibility in the mutant and wild type (NPB) after pre-treatments with 1% NaOH and 1% H2SO4. In addition, silicon supply largely enhanced plant height, mechanical strength and straw biomass production, suggesting that silica rescues mutant growth defects. Hence, this study provides potential approaches for silicon applications in biomass process and bioenergy rice breeding. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

S-layer and cytoplasmic membrane - exceptions from the typical archaeal cell wall with a focus on double membranes.

PubMed

Klingl, Andreas

2014-01-01

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.

Ultrastructure of potato tubers formed in microgravity under controlled environmental conditions

NASA Technical Reports Server (NTRS)

Cook, Martha E.; Croxdale, Judith G.; Tibbitts, T. W. (Principal Investigator)

2003-01-01

Previous spaceflight reports attribute changes in plant ultrastructure to microgravity, but it was thought that the changes might result from growth in uncontrolled environments during spaceflight. To test this possibility, potato explants were examined (a leaf, axillary bud, and small stem segment) grown in the ASTROCULTURETM plant growth unit, which provided a controlled environment. During the 16 d flight of space shuttle Columbia (STS-73), the axillary bud of each explant developed into a mature tuber. Upon return to Earth, tuber slices were examined by transmission electron microscopy. Results showed that the cell ultrastructure of flight-grown tubers could not be distinguished from that of tuber cells grown in the same growth unit on the ground. No differences were observed in cellular features such as protein crystals, plastids with starch grains, mitochondria, rough ER, or plasmodesmata. Cell wall structure, including underlying microtubules, was typical of ground-grown plants. Because cell walls of tubers formed in space were not required to provide support against the force due to gravity, it was hypothesized that these walls might exhibit differences in wall components as compared with walls formed in Earth-grown tubers. Wall components were immunolocalized at the TEM level using monoclonal antibodies JIM 5 and JIM 7, which recognize epitopes of pectins, molecules thought to contribute to wall rigidity and cell adhesion. No difference in presence, abundance or distribution of these pectin epitopes was seen between space- and Earth-grown tubers. This evidence indicates that for the parameters studied, microgravity does not affect the cellular structure of plants grown under controlled environmental conditions.

Properties of the polysaccharide and mucopeptide components of the cell wall of Lactobacillus casei

PubMed Central

Hall, Elizabeth A.; Knox, K. W.

1965-01-01

1. The polysaccharide and mucopeptide components of the cell wall of Lactobacillus casei have been separated by mild conditions of acid hydrolysis. 2. Removal of the polysaccharide renders the mucopeptide susceptible to lysozyme. 3. The mucopeptide and polysaccharide components have been analysed and the results compared with those obtained previously. 4. The polysaccharides responsible for group specificity have a terminal reducing N-acetylgalactosamine residue substituted on C(3) by the adjacent sugar; estimation of this component gave an indication of the molecular weight of the polysaccharides. 5. Evidence has been obtained for the presence of rhamnosyl-(1→3)-N-acetylgalactosamine among the products of acid hydrolysis of the group B polysaccharide. ImagesFig. 2. PMID:5837778

Relationship between skin cell wall composition and anthocyanin extractability of Vitis vinifera L. cv. Tempranillo at different grape ripeness degree.

PubMed

Hernández-Hierro, José Miguel; Quijada-Morín, Natalia; Martínez-Lapuente, Leticia; Guadalupe, Zenaida; Ayestarán, Belén; Rivas-Gonzalo, Julián C; Escribano-Bailón, M Teresa

2014-03-01

The relationship between cell wall composition and extractability of anthocyanins from red grape skins was assessed in Tempranillo grape samples harvested at three stages of ripening (pre-harvest, harvest and over-ripening) and three different contents of soluble solids (22, 24 and 26 °Brix) within each stage. Cell wall material was isolated and analysed in order to determine cellulose, lignin, non-cellulosic polysaccharides, protein, total polyphenols index and the degree of esterification of pectins. Results showed the influence of ripeness degree and contents of soluble solids on cell wall composition. Furthermore, principal components analysis was applied to the obtained data set in order to establish relationships between cell wall composition and extractability of anthocyanins. Total insoluble material exhibits the biggest opposition to anthocyanin extraction, while the highest amounts of cellulose, rhamnogalacturonans-II and polyphenols were positively correlated with anthocyanin extraction. Moreover, multiple linear regression was performed to assess the influence of the cell wall composition on the extraction of anthocyanin compounds. A model connecting cell wall composition and anthocyanin extractabilities was built, explaining 96.2% of the observed variability. Copyright © 2013 Elsevier Ltd. All rights reserved.

Plant cell wall engineering: applications in biofuel production and improved human health.

PubMed

Burton, Rachel A; Fincher, Geoffrey B

2014-04-01

Plant cell walls consist largely of cellulose, non-cellulosic polysaccharides and lignin. Concerted attempts are underway to convert wall polysaccharides from crop plant residues into renewable transport fuels and other valuable products, and to exploit the dietary benefits of cereal grain wall polysaccharides in human health. Attempts to improve plant performance for these applications have involved the manipulation of the levels and structures of wall components. Some successes in altering non-cellulosic polysaccharides has been achieved, but it would appear that drastic changes in cellulose are more difficult to engineer. Nevertheless, future prospects for both genetically modified (GM) and non-GM technologies to modify plant cell wall composition and structure remain bright, and will undoubtedly find applications beyond the current focus on human health and biofuel production. Copyright © 2013. Published by Elsevier Ltd.

Cell Wall Metabolism in Response to Abiotic Stress

PubMed Central

Gall, Hyacinthe Le; Philippe, Florian; Domon, Jean-Marc; Gillet, Françoise; Pelloux, Jérôme; Rayon, Catherine

2015-01-01

This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic), transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i) an increased level in xyloglucan endotransglucosylase/hydrolase (XTH) and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii) an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions. PMID:27135320

Lignin: Characterization of a Multifaceted Crop Component

PubMed Central

2013-01-01

Lignin is a plant component with important implications for various agricultural disciplines. It confers rigidity to cell walls, and is therefore associated with tolerance to abiotic and biotic stresses and the mechanical stability of plants. In animal nutrition, lignin is considered an antinutritive component of forages as it cannot be readily fermented by rumen microbes. In terms of energy yield from biomass, the role of lignin depends on the conversion process. It contains more gross energy than other cell wall components and therefore confers enhanced heat value in thermochemical processes such as direct combustion. Conversely, it negatively affects biological energy conversion processes such as bioethanol or biogas production, as it inhibits microbial fermentation of the cell wall. Lignin from crop residues plays an important role in the soil organic carbon cycling, as it constitutes a recalcitrant carbon pool affecting nutrient mineralization and carbon sequestration. Due to the significance of lignin in several agricultural disciplines, the modification of lignin content and composition by breeding is becoming increasingly important. Both mapping of quantitative trait loci and transgenic approaches have been adopted to modify lignin in crops. However, breeding goals must be defined considering the conflicting role of lignin in different agricultural disciplines. PMID:24348159

Magnetic field exposure stiffens regenerating plant protoplast cell walls.

PubMed

Haneda, Toshihiko; Fujimura, Yuu; Iino, Masaaki

2006-02-01

Single suspension-cultured plant cells (Catharanthus roseus) and their protoplasts were anchored to a glass plate and exposed to a magnetic field of 302 +/- 8 mT for several hours. Compression forces required to produce constant cell deformation were measured parallel to the magnetic field by means of a cantilever-type force sensor. Exposure of intact cells to the magnetic field did not result in any changes within experimental error, while exposure of regenerating protoplasts significantly increased the measured forces and stiffened regenerating protoplasts. The diameters of intact cells or regenerating protoplasts were not changed after exposure to the magnetic field. Measured forces for regenerating protoplasts with and without exposure to the magnetic field increased linearly with incubation time, with these forces being divided into components based on the elasticity of synthesized cell walls and cytoplasm. Cell wall synthesis was also measured using a cell wall-specific fluorescent dye, and no changes were noted after exposure to the magnetic field. Analysis suggested that exposure to the magnetic field roughly tripled the Young's modulus of the newly synthesized cell wall without any lag.

Quantitative trait loci for cell wall composition traits measured using near-infrared spectroscopy in the model C4 perennial grass Panicum hallii

DOE PAGES

Milano, Elizabeth R.; Payne, Courtney E.; Wolfrum, Edward J.; ...

2018-02-03

Biofuels derived from lignocellulosic plant material are an important component of current renewable energy strategies. Improvement efforts in biofuel feedstock crops have been primarily focused on increasing biomass yield with less consideration for tissue quality or composition. Four primary components found in the plant cell wall contribute to the overall quality of plant tissue and conversion characteristics, cellulose and hemicellulose polysaccharides are the primary targets for fuel conversion, while lignin and ash provide structure and defense. We explore the genetic architecture of tissue characteristics using a quantitative trait loci (QTL) mapping approach in Panicum hallii, a model lignocellulosic grass system.more » Diversity in the mapping population was generated by crossing xeric and mesic varietals, comparative to northern upland and southern lowland ecotypes in switchgrass. We use near-infrared spectroscopy with a primary analytical method to create a P. hallii specific calibration model to quickly quantify cell wall components. Ash, lignin, glucan, and xylan comprise 68% of total dry biomass in P. hallii: comparable to other feedstocks. We identified 14 QTL and one epistatic interaction across these four cell wall traits and found almost half of the QTL to localize to a single linkage group. Panicum hallii serves as the genomic model for its close relative and emerging biofuel crop, switchgrass (P. virgatum). We used high throughput phenotyping to map genomic regions that impact natural variation in leaf tissue composition. Understanding the genetic architecture of tissue traits in a tractable model grass system will lead to a better understanding of cell wall structure as well as provide genomic resources for bioenergy crop breeding programs.« less

Quantitative trait loci for cell wall composition traits measured using near-infrared spectroscopy in the model C4 perennial grass Panicum hallii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milano, Elizabeth R.; Payne, Courtney E.; Wolfrum, Edward J.

Biofuels derived from lignocellulosic plant material are an important component of current renewable energy strategies. Improvement efforts in biofuel feedstock crops have been primarily focused on increasing biomass yield with less consideration for tissue quality or composition. Four primary components found in the plant cell wall contribute to the overall quality of plant tissue and conversion characteristics, cellulose and hemicellulose polysaccharides are the primary targets for fuel conversion, while lignin and ash provide structure and defense. We explore the genetic architecture of tissue characteristics using a quantitative trait loci (QTL) mapping approach in Panicum hallii, a model lignocellulosic grass system.more » Diversity in the mapping population was generated by crossing xeric and mesic varietals, comparative to northern upland and southern lowland ecotypes in switchgrass. We use near-infrared spectroscopy with a primary analytical method to create a P. hallii specific calibration model to quickly quantify cell wall components. Ash, lignin, glucan, and xylan comprise 68% of total dry biomass in P. hallii: comparable to other feedstocks. We identified 14 QTL and one epistatic interaction across these four cell wall traits and found almost half of the QTL to localize to a single linkage group. Panicum hallii serves as the genomic model for its close relative and emerging biofuel crop, switchgrass (P. virgatum). We used high throughput phenotyping to map genomic regions that impact natural variation in leaf tissue composition. Understanding the genetic architecture of tissue traits in a tractable model grass system will lead to a better understanding of cell wall structure as well as provide genomic resources for bioenergy crop breeding programs.« less

Neurospora crassa 1,3-α-glucan synthase, AGS-1, is required for cell wall biosynthesis during macroconidia development

PubMed Central

Fu, Ci; Tanaka, Asuma

2014-01-01

The Neurospora crassa genome encodes two 1,3-α-glucan synthases. One of these 1,3-α-glucan synthase genes, ags-1, was shown to be required for the synthesis of 1,3-α-glucan in the aerial hyphae and macroconidia cell walls. 1,3-α-Glucan was found in the conidia cell wall, but was absent from the vegetative hyphae cell wall. Deletion of ags-1 affected conidial development. Δags-1 produced only 5 % as many conidia as the WT and most of the conidia produced by Δags-1 were not viable. The ags-1 upstream regulatory elements were shown to direct cell-type-specific expression of red fluorescent protein in conidia and aerial hyphae. A haemagglutinin-tagged AGS-1 was found to be expressed in aerial hyphae and conidia. The research showed that 1,3-α-glucan is an aerial hyphae and conidia cell wall component, and is required for normal conidial differentiation. PMID:24847001

An Arabidopsis gene regulatory network for secondary cell wall synthesis

DOE PAGES

Taylor-Teeples, M.; Lin, L.; de Lucas, M.; ...

2014-12-24

The plant cell wall is an important factor for determining cell shape, function and response to the environment. Secondary cell walls, such as those found in xylem, are composed of cellulose, hemicelluloses and lignin and account for the bulk of plant biomass. The coordination between transcriptional regulation of synthesis for each polymer is complex and vital to cell function. A regulatory hierarchy of developmental switches has been proposed, although the full complement of regulators remains unknown. In this paper, we present a protein–DNA network between Arabidopsis thaliana transcription factors and secondary cell wall metabolic genes with gene expression regulated bymore » a series of feed-forward loops. This model allowed us to develop and validate new hypotheses about secondary wall gene regulation under abiotic stress. Distinct stresses are able to perturb targeted genes to potentially promote functional adaptation. Finally, these interactions will serve as a foundation for understanding the regulation of a complex, integral plant component.« less

Structural characterization of a mixed-linkage glucan deficient mutant reveals alteration in cellulose microfibril orientation in rice coleoptile mesophyll cell walls

PubMed Central

Smith-Moritz, Andreia M.; Hao, Zhao; Fernández-Niño, Susana G.; Fangel, Jonatan U.; Verhertbruggen, Yves; Holman, Hoi-Ying N.; Willats, William G. T.; Ronald, Pamela C.; Scheller, Henrik V.; Heazlewood, Joshua L.; Vega-Sánchez, Miguel E.

2015-01-01

The CELLULOSE SYNTHASE-LIKE F6 (CslF6) gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG), a cell wall polysaccharide that is hypothesized to be tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to test the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of 3 day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared (FTM-IR) Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell walls of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion. PMID:26347754

Structural characterization of a mixed-linkage glucan deficient mutant reveals alteration in cellulose microfibril orientation in rice coleoptile mesophyll cell walls

DOE PAGES

Smith-Moritz, Andreia M.; Hao, Zhao; Fernández-Nino, Susana G.; ...

2015-08-18

The CELLULOSE SYNTHASE-LIKE F6 (CslF6) gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG), a cell wall polysaccharide that is hypothesized to be tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to testmore » the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of 3 day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared (FTM-IR) Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell walls of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Finally, taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion.« less

Cell wall properties play an important role in the emergence of lateral root primordia from the parent root.

PubMed

Roycewicz, Peter S; Malamy, Jocelyn E

2014-05-01

Plants adapt to their unique soil environments by altering the number and placement of lateral roots post-embryonic. Mutants were identified in Arabidopsis thaliana that exhibit increased lateral root formation. Eight mutants were characterized in detail and were found to have increased lateral root formation due to at least three distinct mechanisms. The causal mutation in one of these mutants was found in the XEG113 gene, recently shown to be involved in plant cell wall biosynthesis. Lateral root primordia initiation is unaltered in this mutant. In contrast, synchronization of lateral root initiation demonstrated that mutation of XEG113 increases the rate at which lateral root primordia develop and emerge to form lateral roots. The effect of the XEG113 mutation was specific to the root system and had no apparent effect on shoot growth. Screening of 17 additional cell wall mutants, altering a myriad of cell wall components, revealed that many (but not all) types of cell wall defects promote lateral root formation. These results suggest that proper cell wall biosynthesis is necessary to constrain lateral root primordia emergence. While previous reports have shown that lateral root emergence is accompanied by active remodelling of cell walls overlying the primordia, this study is the first to demonstrate that alteration of the cell wall is sufficient to promote lateral root formation. Therefore, inherent cell wall properties may play a previously unappreciated role in regulation of root system architecture.

Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level

PubMed Central

Derbyshire, Paul; McCann, Maureen C; Roberts, Keith

2007-01-01

Background Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing) cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. Results We present evidence that the degree of pectin methyl-esterification (DE%) limits cell growth, and that a minimum level of about 60% DE is required for normal cell elongation in Arabidopsis hypocotyls. When the average DE% falls below this level, as in two gibberellic acid (GA) mutants ga1-3 and gai, and plants expressing pectin methyl-esterase (PME1) from Aspergillus aculeatus, then hypocotyl elongation is reduced. Conclusion Low average levels of pectin DE% are associated with reduced cell elongation, implicating PMEs, the enzymes that regulate DE%, in the cell elongation process and in responses to GA. At high average DE% other components of the cell wall limit GA-induced growth. PMID:17572910

Restricted cell elongation in Arabidopsis hypocotyls is associated with a reduced average pectin esterification level.

PubMed

Derbyshire, Paul; McCann, Maureen C; Roberts, Keith

2007-06-17

Cell elongation is mainly limited by the extensibility of the cell wall. Dicotyledonous primary (growing) cell walls contain cellulose, xyloglucan, pectin and proteins, but little is known about how each polymer class contributes to the cell wall mechanical properties that control extensibility. We present evidence that the degree of pectin methyl-esterification (DE%) limits cell growth, and that a minimum level of about 60% DE is required for normal cell elongation in Arabidopsis hypocotyls. When the average DE% falls below this level, as in two gibberellic acid (GA) mutants ga1-3 and gai, and plants expressing pectin methyl-esterase (PME1) from Aspergillus aculeatus, then hypocotyl elongation is reduced. Low average levels of pectin DE% are associated with reduced cell elongation, implicating PMEs, the enzymes that regulate DE%, in the cell elongation process and in responses to GA. At high average DE% other components of the cell wall limit GA-induced growth.

The cell-wall glycoproteins of the green alga Scenedesmus obliquus. The predominant cell-wall polypeptide of Scenedesmus obliquus is related to the cell-wall glycoprotein gp3 of Chlamydomonas reinhardtii.

PubMed

Voigt, Jürgen; Stolarczyk, Adam; Zych, Maria; Malec, Przemysław; Burczyk, Jan

2014-02-01

The green alga Scenedesmus obliquus contains a multilayered cell wall, ultrastructurally similar to that of Chlamydomonas reinhardtii, although its proportion of hydroxyproline is considerably lower. Therefore, we have investigated the polypeptide composition of the insoluble and the chaotrope-soluble wall fractions of S. obliquus. The polypeptide pattern of the chaotrope-soluble wall fraction was strongly modified by chemical deglycosylation with anhydrous hydrogen fluoride (HF) in pyridine indicating that most of these polypeptides are glycosylated. Polypeptide constituents of the chaotrope-soluble cell-wall fraction with apparent molecular masses of 240, 270, 265, and 135 kDa cross-reacted with a polyclonal antibody raised against the 100 kDa deglycosylation product of the C. reinhardtii cell-wall glycoprotein GP3B. Chemical deglycosylation of the chaotrope-soluble wall fraction resulted in a 135 kDa major polypeptide and a 106 kDa minor component reacting with the same antibody. This antibody recognized specific peptide epitopes of GP3B. When the insoluble wall fraction of S. obliquus was treated with anhydrous HF/pyridine, three polypeptides with apparent molecular masses of 144, 135, and 65 kDa were solubilized, which also occured in the deglycosylated chaotrope-soluble wall fraction. These findings indicate that theses glycoproteins are cross-linked to the insoluble wall fraction via HF-sensitive bonds. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

The Dual Activity Responsible for the Elongation and Branching of β-(1,3)-Glucan in the Fungal Cell Wall.

PubMed

Aimanianda, Vishukumar; Simenel, Catherine; Garnaud, Cecile; Clavaud, Cecile; Tada, Rui; Barbin, Lise; Mouyna, Isabelle; Heddergott, Christoph; Popolo, Laura; Ohya, Yoshikazu; Delepierre, Muriel; Latge, Jean-Paul

2017-06-20

β-(1,3)-Glucan, the major fungal cell wall component, ramifies through β-(1,6)-glycosidic linkages, which facilitates its binding with other cell wall components contributing to proper cell wall assembly. Using Saccharomyces cerevisiae as a model, we developed a protocol to quantify β-(1,6)-branching on β-(1,3)-glucan. Permeabilized S. cerevisiae and radiolabeled substrate UDP-( 14 C)glucose allowed us to determine branching kinetics. A screening aimed at identifying deletion mutants with reduced branching among them revealed only two, the bgl2 Δ and gas1 Δ mutants, showing 15% and 70% reductions in the branching, respectively, compared to the wild-type strain. Interestingly, a recombinant Gas1p introduced β-(1,6)-branching on the β-(1,3)-oligomers following its β-(1,3)-elongase activity. Sequential elongation and branching activity of Gas1p occurred on linear β-(1,3)-oligomers as well as Bgl2p-catalyzed products [short β-(1,3)-oligomers linked by a linear β-(1,6)-linkage]. The double S. cerevisiae gas1 Δ bgl2 Δ mutant showed a drastically sick phenotype. An Sc Gas1p ortholog, Gel4p from Aspergillus fumigatus , also showed dual β-(1,3)-glucan elongating and branching activity. Both Sc Gas1p and A. fumigatus Gel4p sequences are endowed with a carbohydrate binding module (CBM), CBM43, which was required for the dual β-(1,3)-glucan elongating and branching activity. Our report unravels the β-(1,3)-glucan branching mechanism, a phenomenon occurring during construction of the cell wall which is essential for fungal life. IMPORTANCE The fungal cell wall is essential for growth, morphogenesis, protection, and survival. In spite of being essential, cell wall biogenesis, especially the core β-(1,3)-glucan ramification, is poorly understood; the ramified β-(1,3)-glucan interconnects other cell wall components. Once linear β-(1,3)-glucan is synthesized by plasma membrane-bound glucan synthase, the subsequent event is its branching event in the cell wall space. Using Saccharomyces cerevisiae as a model, we identified GH72 and GH17 family glycosyltransferases, Gas1p and Bgl2p, respectively, involved in the β-(1,3)-glucan branching. The sick phenotype of the double Scgas1 Δ bgl2 Δ mutant suggested that β-(1,3)-glucan branching is essential. In addition to Sc Gas1p, GH72 family Sc Gas2p and Aspergillus fumigatus Gel4p, having CBM43 in their sequences, showed dual β-(1,3)-glucan elongating and branching activity. Our report identifies the fungal cell wall β-(1,3)-glucan branching mechanism. The essentiality of β-(1,3)-glucan branching suggests that enzymes involved in the glucan branching could be exploited as antifungal targets. Copyright © 2017 Aimanianda et al.

Characterizing visible and invisible cell wall mutant phenotypes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carpita, Nicholas C.; McCann, Maureen C.

2015-04-06

About 10% of a plant's genome is devoted to generating the protein machinery to synthesize, remodel, and deconstruct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with ‘invisible’ phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basismore » of deviation from the wild type in genetic functional analyses to insights provided by modern analytical techniques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide components of the plant cell wall.« less

Potential for utilization of algal biomass for components of the diet in CELSS

NASA Technical Reports Server (NTRS)

Kamarei, A. R.; Nakhost, Z.; Karel, M.

1986-01-01

The major nutritional components of the green algae (Scenedesmus obliquus) grown in a Constant Cell Density Apparatus were determined. Suitable methodology to prepare proteins from which three major undesirable components of these cells (i.e., cell walls, nucleic acids, and pigments) were either removed or substantially reduced was developed. Results showed that processing of green algae to protein isolate enhances is potential nutritional and organoleptic acceptability as a diet component in controlled Ecological Life Support System.

Dissecting the molecular mechanism underlying the intimate relationship between cellulose microfibrils and cortical microtubules.

PubMed

Lei, Lei; Li, Shundai; Bashline, Logan; Gu, Ying

2014-01-01

A central question in plant cell development is how the cell wall determines directional cell expansion and therefore the final shape of the cell. As the major load-bearing component of the cell wall, cellulose microfibrils are laid down transversely to the axis of elongation, thus forming a spring-like structure that reinforces the cell laterally and while favoring longitudinal expansion in most growing cells. Mounting evidence suggests that cortical microtubules organize the deposition of cellulose microfibrils, but the precise molecular mechanisms linking microtubules to cellulose organization have remained unclear until the recent discovery of cellulose synthase interactive protein 1 , a linker protein between the cortical microtubules and the cellulose biosynthesizing machinery. In this review, we will focus on the intimate relationship between cellulose microfibrils and cortical microtubules, in particular, we will discuss microtubule arrangement and cell wall architecture, the linkage between cellulose synthase complexes and microtubules, and the feedback mechanisms between cell wall and microtubules.

Influence of different yeast cell wall preparations and their components on performance and immune and metabolic pathways in Clostridium perfringens-challenged broiler chicks

USDA-ARS?s Scientific Manuscript database

A study was conducted to evaluate the influence of purification of yeast cell wall (YCW) preparations on broiler performance, and immunogenic and metabolic pathways under microbial challenge. A total of 240 day-of-hatch chicks were distributed among two battery brooder units (48 pens; 5 birds/pen; ...

MmpL genes are associated with mycolic acid metabolism in mycobacteria and corynebacteria.

PubMed

Varela, Cristian; Rittmann, Doris; Singh, Albel; Krumbach, Karin; Bhatt, Kiranmai; Eggeling, Lothar; Besra, Gurdyal S; Bhatt, Apoorva

2012-04-20

Mycolic acids are vital components of the cell wall of the tubercle bacillus Mycobacterium tuberculosis and are required for viability and virulence. While mycolic acid biosynthesis is studied extensively, components involved in mycolate transport remain unidentified. We investigated the role of large membrane proteins encoded by mmpL genes in mycolic acid transport in mycobacteria and the related corynebacteria. MmpL3 was found to be essential in mycobacteria and conditional depletion of MmpL3 in Mycobacterium smegmatis resulted in loss of cell wall mycolylation, and of the cell wall-associated glycolipid, trehalose dimycolate. In parallel, an accumulation of trehalose monomycolate (TMM) was observed, suggesting that mycolic acids were transported as TMM. In contrast to mycobacteria, we found redundancy in the role of two mmpL genes, in Corynebacterium glutamicum; a complete loss of trehalose-associated and cell wall bound corynomycolates was observed in an NCgl0228-NCgl2769 double mutant, but not in individual single mutants. Our studies highlight the role of mmpL genes in mycolic acid metabolism and identify potential new targets for anti-TB drug development. Copyright © 2012 Elsevier Ltd. All rights reserved.

Immunological Approaches to Biomass Characterization and Utilization

PubMed Central

Pattathil, Sivakumar; Avci, Utku; Zhang, Tiantian; Cardenas, Claudia L.; Hahn, Michael G.

2015-01-01

Plant biomass is the major renewable feedstock resource for sustainable generation of alternative transportation fuels to replace fossil carbon-derived fuels. Lignocellulosic cell walls are the principal component of plant biomass. Hence, a detailed understanding of plant cell wall structure and biosynthesis is an important aspect of bioenergy research. Cell walls are dynamic in their composition and structure, varying considerably among different organs, cells, and developmental stages of plants. Hence, tools are needed that are highly efficient and broadly applicable at various levels of plant biomass-based bioenergy research. The use of plant cell wall glycan-directed probes has seen increasing use over the past decade as an excellent approach for the detailed characterization of cell walls. Large collections of such probes directed against most major cell wall glycans are currently available worldwide. The largest and most diverse set of such probes consists of cell wall glycan-directed monoclonal antibodies (McAbs). These McAbs can be used as immunological probes to comprehensively monitor the overall presence, extractability, and distribution patterns among cell types of most major cell wall glycan epitopes using two mutually complementary immunological approaches, glycome profiling (an in vitro platform) and immunolocalization (an in situ platform). Significant progress has been made recently in the overall understanding of plant biomass structure, composition, and modifications with the application of these immunological approaches. This review focuses on such advances made in plant biomass analyses across diverse areas of bioenergy research. PMID:26579515

Monitoring Meso-Scale Ordering of Cellulose in Intact Plant Cell Walls Using Sum Frequency Generation Spectroscopy1[C][W][OPEN

PubMed Central

Park, Yong Bum; Lee, Christopher M.; Koo, Bon-Wook; Park, Sunkyu; Cosgrove, Daniel J.; Kim, Seong H.

2013-01-01

Sum frequency generation (SFG) vibration spectroscopy can selectively detect crystalline cellulose without spectral interference from cell wall matrix components. Here, we show that the cellulose SFG spectrum is sensitive to cellulose microfibril alignment and packing within the cell wall. SFG intensity at 2,944 cm−1 correlated well with crystalline cellulose contents of various regions of the Arabidopsis (Arabidopsis thaliana) inflorescence, while changes in the 3,320/2,944 cm−1 intensity ratio suggest subtle changes in cellulose ordering as tissues mature. SFG analysis of two cellulose synthase mutants (irx1/cesa8 and irx3/cesa7) indicates a reduction in cellulose content without evidence of altered cellulose structure. In primary cell walls of Arabidopsis, cellulose exhibited a characteristic SFG peak at 2,920 and 3,320 cm−1, whereas in secondary cell walls, it had peaks at 2,944 and 3,320 cm−1. Starch (amylose) gave an SFG peak at 2,904 cm−1 (CH methine) whose intensity increased with light exposure prior to harvest. Selective removal of matrix polysaccharides from primary cell walls by acid hydrolysis resulted in an SFG spectrum resembling that of secondary wall cellulose. Our results show that SFG spectroscopy is sensitive to the ordering of cellulose microfibrils in plant cell walls at the meso scale (nm to μm) that is important for cell wall architecture but cannot be probed by other spectroscopic or diffraction techniques. PMID:23995148

Monitoring meso-scale ordering of cellulose in intact plant cell walls using sum frequency generation spectroscopy.

PubMed

Park, Yong Bum; Lee, Christopher M; Koo, Bon-Wook; Park, Sunkyu; Cosgrove, Daniel J; Kim, Seong H

2013-10-01

Sum frequency generation (SFG) vibration spectroscopy can selectively detect crystalline cellulose without spectral interference from cell wall matrix components. Here, we show that the cellulose SFG spectrum is sensitive to cellulose microfibril alignment and packing within the cell wall. SFG intensity at 2,944 cm(-1) correlated well with crystalline cellulose contents of various regions of the Arabidopsis (Arabidopsis thaliana) inflorescence, while changes in the 3,320/2,944 cm(-1) intensity ratio suggest subtle changes in cellulose ordering as tissues mature. SFG analysis of two cellulose synthase mutants (irx1/cesa8 and irx3/cesa7) indicates a reduction in cellulose content without evidence of altered cellulose structure. In primary cell walls of Arabidopsis, cellulose exhibited a characteristic SFG peak at 2,920 and 3,320 cm(-1), whereas in secondary cell walls, it had peaks at 2,944 and 3,320 cm(-1). Starch (amylose) gave an SFG peak at 2,904 cm(-1) (CH methine) whose intensity increased with light exposure prior to harvest. Selective removal of matrix polysaccharides from primary cell walls by acid hydrolysis resulted in an SFG spectrum resembling that of secondary wall cellulose. Our results show that SFG spectroscopy is sensitive to the ordering of cellulose microfibrils in plant cell walls at the meso scale (nm to μm) that is important for cell wall architecture but cannot be probed by other spectroscopic or diffraction techniques.

12. Interior view of Test Cell 9 (fuel) in Components ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. Interior view of Test Cell 9 (fuel) in Components Test Laboratory (T-27), showing north and east walls. Photograph shows upgraded instrumentation, piping, and technological modifications installed in 1997-99 to accommodate testing requirements for the Atlas V missile. - Air Force Plant PJKS, Systems Integration Laboratory, Components Test Laboratory, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

Mutational Analysis of the Glycosylphosphatidylinositol (GPI) Anchor Pathway Demonstrates that GPI-Anchored Proteins Are Required for Cell Wall Biogenesis and Normal Hyphal Growth in Neurospora crassa

PubMed Central

Bowman, Shaun M.; Piwowar, Amy; Al Dabbous, Mash'el; Vierula, John; Free, Stephen J.

2006-01-01

Using mutational and proteomic approaches, we have demonstrated the importance of the glycosylphosphatidylinositol (GPI) anchor pathway for cell wall synthesis and integrity and for the overall morphology of the filamentous fungus Neurospora crassa. Mutants affected in the gpig-1, gpip-1, gpip-2, gpip-3, and gpit-1 genes, which encode components of the N. crassa GPI anchor biosynthetic pathway, have been characterized. GPI anchor mutants exhibit colonial morphologies, significantly reduced rates of growth, altered hyphal growth patterns, considerable cellular lysis, and an abnormal “cell-within-a-cell” phenotype. The mutants are deficient in the production of GPI-anchored proteins, verifying the requirement of each altered gene for the process of GPI-anchoring. The mutant cell walls are abnormally weak, contain reduced amounts of protein, and have an altered carbohydrate composition. The mutant cell walls lack a number of GPI-anchored proteins, putatively involved in cell wall biogenesis and remodeling. From these studies, we conclude that the GPI anchor pathway is critical for proper cell wall structure and function in N. crassa. PMID:16524913

Aspergillus fumigatus Trehalose-Regulatory Subunit Homolog Moonlights To Mediate Cell Wall Homeostasis through Modulation of Chitin Synthase Activity.

PubMed

Thammahong, Arsa; Caffrey-Card, Alayna K; Dhingra, Sourabh; Obar, Joshua J; Cramer, Robert A

2017-04-25

Trehalose biosynthesis is found in fungi but not humans. Proteins involved in trehalose biosynthesis are essential for fungal pathogen virulence in humans and plants through multiple mechanisms. Loss of canonical trehalose biosynthesis genes in the human pathogen Aspergillus fumigatus significantly alters cell wall structure and integrity, though the mechanistic link between these virulence-associated pathways remains enigmatic. Here we characterize genes, called tslA and tslB , which encode proteins that contain domains similar to those corresponding to trehalose-6-phosphate phosphatase but lack critical catalytic residues for phosphatase activity. Loss of tslA reduces trehalose content in both conidia and mycelia, impairs cell wall integrity, and significantly alters cell wall structure. To gain mechanistic insights into the role that TslA plays in cell wall homeostasis, immunoprecipitation assays coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to reveal a direct interaction between TslA and CsmA, a type V chitin synthase enzyme. TslA regulates not only chitin synthase activity but also CsmA sub-cellular localization. Loss of TslA impacts the immunopathogenesis of murine invasive pulmonary aspergillosis through altering cytokine production and immune cell recruitment. In conclusion, our data provide a novel model whereby proteins in the trehalose pathway play a direct role in fungal cell wall homeostasis and consequently impact fungus-host interactions. IMPORTANCE Human fungal infections are increasing globally due to HIV infections and increased use of immunosuppressive therapies for many diseases. Therefore, new antifungal drugs with reduced side effects and increased efficacy are needed to improve treatment outcomes. Trehalose biosynthesis exists in pathogenic fungi and is absent in humans. Components of the trehalose biosynthesis pathway are important for the virulence of human-pathogenic fungi, including Aspergillus fumigatus Consequently, it has been proposed that components of this pathway are potential targets for antifungal drug development. However, how trehalose biosynthesis influences the fungus-host interaction remains enigmatic. One phenotype associated with fungal trehalose biosynthesis mutants that remains enigmatic is cell wall perturbation. Here we discovered a novel moonlighting role for a regulatory-like subunit of the trehalose biosynthesis pathway in A. fumigatus that regulates cell wall homeostasis through modulation of chitin synthase localization and activity. As the cell wall is a current and promising therapeutic target for fungal infections, understanding the role of trehalose biosynthesis in cell wall homeostasis and virulence is expected to help define new therapeutic opportunities. Copyright © 2017 Thammahong et al.

Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups

PubMed Central

Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A.; Bar-On, Benny

2017-01-01

Background and Aims Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. Methods A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns (Asplenium nidus and Platycerium bifurcatum) and angiosperms (Arabidopsis thaliana and Commelina erecta) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata (Sorghum bicolor and Triticum aestivum). Key Results Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. Conclusions The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn could be a consequence of differences in environmental selection along the course of plant evolution. PMID:28158449

Pectin: cell biology and prospects for functional analysis.

PubMed

Willats, W G; McCartney, L; Mackie, W; Knox, J P

2001-09-01

Pectin is a major component of primary cell walls of all land plants and encompasses a range of galacturonic acid-rich polysaccharides. Three major pectic polysaccharides (homogalacturonan, rhamnogalacturonan-I and rhamnogalacturonan-II) are thought to occur in all primary cell walls. This review surveys what is known about the structure and function of these pectin domains. The high degree of structural complexity and heterogeneity of the pectic matrix is produced both during biosynthesis in the endomembrane system and as a result of the action of an array of wall-based pectin-modifying enzymes. Recent developments in analytical techniques and in the generation of anti-pectin probes have begun to place the structural complexity of pectin in cell biological and developmental contexts. The in muro de-methyl-esterification of homogalacturonan by pectin methyl esterases is emerging as a key process for the local modulation of matrix properties. Rhamnogalacturonan-I comprises a highly diverse population of spatially and developmentally regulated polymers, whereas rhamnogalacturonan-II appears to be a highly conserved and stable pectic domain. Current knowledge of biosynthetic enzymes, plant and microbial pectinases and the interactions of pectin with other cell wall components and the impact of molecular genetic approaches are reviewed in terms of the functional analysis of pectic polysaccharides in plant growth and development.

An Iron-Regulated Autolysin Remodels the Cell Wall To Facilitate Heme Acquisition in Staphylococcus lugdunensis

PubMed Central

Farrand, Allison J.; Haley, Kathryn P.; Lareau, Nichole M.; Heilbronner, Simon; McLean, John A.; Foster, Timothy

2015-01-01

Bacteria alter their cell surface in response to changing environments, including those encountered upon invasion of a host during infection. One alteration that occurs in several Gram-positive pathogens is the presentation of cell wall-anchored components of the iron-regulated surface determinant (Isd) system, which extracts heme from host hemoglobin to fulfill the bacterial requirement for iron. Staphylococcus lugdunensis, an opportunistic pathogen that causes infective endocarditis, encodes an Isd system. Unique among the known Isd systems, S. lugdunensis contains a gene encoding a putative autolysin located adjacent to the Isd operon. To elucidate the function of this putative autolysin, here named IsdP, we investigated its contribution to Isd protein localization and hemoglobin-dependent iron acquisition. S. lugdunensis IsdP was found to be iron regulated and cotranscribed with the Isd operon. IsdP is a specialized peptidoglycan hydrolase that cleaves the stem peptide and pentaglycine crossbridge of the cell wall and alters processing and anchoring of a major Isd system component, IsdC. Perturbation of IsdC localization due to isdP inactivation results in a hemoglobin utilization growth defect. These studies establish IsdP as an autolysin that functions in heme acquisition and describe a role for IsdP in cell wall reorganization to accommodate nutrient uptake systems during infection. PMID:26123800

New phenotypic aspects of the decidual spiral artery wall during early post-implantation mouse pregnancy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elia, Artemis; Charalambous, Fotini; Georgiades, Pantelis, E-mail: pgeor@ucy.ac.cy

Highlights: Black-Right-Pointing-Pointer Spiral artery (SA) wall remodeling (SAR) is ill-defined and clinically important. Black-Right-Pointing-Pointer SA muscular phenotype prior to and during SAR in mice is underexplored. Black-Right-Pointing-Pointer SA muscular wall consists of contractile and non-contractile components. Black-Right-Pointing-Pointer SA wall non-contractile component may be synthetic smooth muscle. Black-Right-Pointing-Pointer Timing and extent of SA wall contractile component loss is revealed. -- Abstract: During pregnancy the walls of decidual spiral arteries (SAs) undergo clinically important structural modifications crucial for embryo survival/growth and maternal health. However, the mechanisms of SA remodeling (SAR) are poorly understood. Although an important prerequisite to this understanding is knowledgemore » about the phenotype of SA muscular wall prior to and during the beginning of mouse SAR, this remains largely unexplored and was the main aim of this work. Using histological and immunohistochemical techniques, this study shows for the first time that during early mouse gestation, from embryonic day 7.5 (E7.5) to E10.5, the decidual SA muscular coat is not a homogeneous structure, but consists of two concentric layers. The first is a largely one cell-thick sub-endothelial layer of contractile mural cells (positive for {alpha}-smooth muscle actin, calponin and SM22{alpha}) with pericyte characteristics (NG2 positive). The second layer is thicker, and evidence is presented that it may be of the synthetic/proliferative smooth muscle phenotype, based on absence ({alpha}-smooth muscle actin and calponin) or weak (SM22{alpha}) expression of contractile mural cell markers, and presence of synthetic smooth muscle characteristics (expression of non-muscle Myosin heavy chain-IIA and of the cell proliferation marker PCNA). Importantly, immunohistochemistry and morphometrics showed that the contractile mural cell layer although prominent at E7.5-E8.5, becomes drastically reduced by E10.5 and is undetectable by E12.5. In conclusion, this study reveals novel aspects of the decidual SA muscular coat phenotype prior to and during early SAR that may have important implications for understanding the mechanisms of SAR.« less

Visualization of sporopollenin-containing pathogenic green micro-alga Prototheca wickerhamii by fluorescent in situ hybridization (FISH).

PubMed

Ueno, Ryohei

2009-04-01

Fluorescent in situ hybridization (FISH) using taxon-specific, rRNA-targeted oligonucleotide probes is one of the most powerful tools for the rapid identification of harmful microorganisms. However, eukaryotic algal cells do not always allow FISH probes to permeate over their cell walls. Members of the pathogenic micro-algal genus Prototheca are characterized by their distinctive cell-wall component, sporopollenin, an extremely tough biopolymer that resists acid and alkaline hydrolysis, enzyme attack, and acetolysis. To our knowledge, there has been no report of the successful permeation by the oligonucleotide probes over the cell walls of unicellular green micro-algae, which contain sporopollenin. The DNA probes passed through the cell wall of Prototheca wickerhamii after treating the algal cells with cetyltrimethylammonium bromide (CTAB). Most cells in the middle logarithmic growth phase culture fluoresced when hybridized with the rRNA-targeted universal probe for eukaryotes, though individual cells included in this culture differed in the level of cell-wall vulnerability to attack by the polysaccharide-degrading enzyme, thus reflecting the different stages of the life cycle. This is the first report regarding the visualization of sporopollenin-containing, green micro-algal cells by FISH.

Understanding how the complex molecular architecture of mannan-degrading hydrolases contributes to plant cell wall degradation.

PubMed

Zhang, Xiaoyang; Rogowski, Artur; Zhao, Lei; Hahn, Michael G; Avci, Utku; Knox, J Paul; Gilbert, Harry J

2014-01-24

Microbial degradation of plant cell walls is a central component of the carbon cycle and is of increasing importance in environmentally significant industries. Plant cell wall-degrading enzymes have a complex molecular architecture consisting of catalytic modules and, frequently, multiple non-catalytic carbohydrate binding modules (CBMs). It is currently unclear whether the specificities of the CBMs or the topology of the catalytic modules are the primary drivers for the specificity of these enzymes against plant cell walls. Here, we have evaluated the relationship between CBM specificity and their capacity to enhance the activity of GH5 and GH26 mannanases and CE2 esterases against intact plant cell walls. The data show that cellulose and mannan binding CBMs have the greatest impact on the removal of mannan from tobacco and Physcomitrella cell walls, respectively. Although the action of the GH5 mannanase was independent of the context of mannan in tobacco cell walls, a significant proportion of the polysaccharide was inaccessible to the GH26 enzyme. The recalcitrant mannan, however, was fully accessible to the GH26 mannanase appended to a cellulose binding CBM. Although CE2 esterases display similar specificities against acetylated substrates in vitro, only CjCE2C was active against acetylated mannan in Physcomitrella. Appending a mannan binding CBM27 to CjCE2C potentiated its activity against Physcomitrella walls, whereas a xylan binding CBM reduced the capacity of esterases to deacetylate xylan in tobacco walls. This work provides insight into the biological significance for the complex array of hydrolytic enzymes expressed by plant cell wall-degrading microorganisms.

Role of protein phosphomannosylation in the Candida tropicalis-macrophage interaction.

PubMed

Hernández-Chávez, Marco J; Franco, Bernardo; Clavijo-Giraldo, Diana M; Hernández, Nahúm V; Estrada-Mata, Eine; Mora-Montes, Héctor Manuel

2018-04-27

Candida tropicalis is an opportunistic fungal pathogen responsible for mucosal and systemic infections. The cell wall is the initial contact point between a fungal cell and the host immune system, and mannoproteins are important components that play key roles when interacting with host cells. In C. albicans, mannans are modified by mannosyl-phosphate moieties, named phosphomannans, which can work as molecular scaffolds to synthesize β1,2-mannooligosaccharides, and MNN4 is a positive regulator of the phosphomannosylation pathway. Here, we showed that C. tropicalis also displays phosphomannans on the cell surface, but the amount of this cell wall component varies depending on the fungal strain. We also identified a functional ortholog of CaMNN4 in C. tropicalis. Disruption of this gene caused depletion of phosphomannan content. The C. tropicalis mnn4Δ did not show defects in the ability to stimulate cytokine production by human mononuclear cells but displayed virulence attenuation in an insect model of candidiasis. When the mnn4Δ-macrophage interaction was analyzed, results showed that presence of cell wall phosphomannan was critical for C. tropicalis phagocytosis. Finally, our results strongly suggest a differential role for phosphomannans during phagocytosis of C. albicans and C. tropicalis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith-Moritz, Andreia M.; Hao, Zhao; Fernández-Nino, Susana G.

The CELLULOSE SYNTHASE-LIKE F6 (CslF6) gene was previously shown to mediate the biosynthesis of mixed-linkage glucan (MLG), a cell wall polysaccharide that is hypothesized to be tightly associated with cellulose and also have a role in cell expansion in the primary cell wall of young seedlings in grass species. We have recently shown that loss-of-function cslf6 rice mutants do not accumulate MLG in most vegetative tissues. Despite the absence of a structurally important polymer, MLG, these mutants are unexpectedly viable and only show a moderate growth compromise compared to wild type. Therefore these mutants are ideal biological systems to testmore » the current grass cell wall model. In order to gain a better understanding of the role of MLG in the primary wall, we performed in-depth compositional and structural analyses of the cell walls of 3 day-old rice seedlings using various biochemical and novel microspectroscopic approaches. We found that cellulose content as well as matrix polysaccharide composition was not significantly altered in the MLG deficient mutant. However, we observed a significant change in cellulose microfibril bundle organization in mesophyll cell walls of the cslf6 mutant. Using synchrotron source Fourier Transform Mid-Infrared (FTM-IR) Spectromicroscopy for high-resolution imaging, we determined that the bonds associated with cellulose and arabinoxylan, another major component of the primary cell walls of grasses, were in a lower energy configuration compared to wild type, suggesting a slightly weaker primary wall in MLG deficient mesophyll cells. Finally, taken together, these results suggest that MLG may influence cellulose deposition in mesophyll cell walls without significantly affecting anisotropic growth thus challenging MLG importance in cell wall expansion.« less

Arabidopsis phyllotaxis is controlled by the methyl-esterification status of cell-wall pectins.

PubMed

Peaucelle, Alexis; Louvet, Romain; Johansen, Jorunn N; Höfte, Herman; Laufs, Patrick; Pelloux, Jérome; Mouille, Grégory

2008-12-23

Plant organs are produced from meristems in a characteristic pattern. This pattern, referred to as phyllotaxis, is thought to be generated by local gradients of an information molecule, auxin. Some studies propose a key role for the mechanical properties of the cell walls in the control of organ outgrowth. A major cell-wall component is the linear alpha-1-4-linked D-GalAp pectic polysaccharide homogalacturonan (HG), which plays a key role in cell-to-cell cohesion. HG is deposited in the cell wall in a highly (70%-80%) methyl-esterified form and is subsequently de-methyl-esterified by pectin methyl-esterases (PME, EC 3.1.1.11). PME activity is itself regulated by endogenous PME inhibitor (PMEI) proteins. PME action modulates cell-wall-matrix properties and plays a role in the control of cell growth. Here, we show that the formation of flower primordia in the Arabidopsis shoot apical meristem is accompanied by the de-methyl-esterification of pectic polysaccharides in the cell walls. In addition, experimental perturbation of the methyl-esterification status of pectins within the meristem dramatically alters the phyllotactic pattern. These results demonstrate that regulated de-methyl-esterification of pectins is a key event in the outgrowth of primordia and possibly also in phyllotactic patterning.

Cell Wall Structure in Cells Adapted to Growth on the Cellulose-Synthesis Inhibitor 2,6-Dichlorobenzonitrile 1

PubMed Central

Shedletzky, Esther; Shmuel, Miri; Trainin, Tali; Kalman, Sara; Delmer, Deborah

1992-01-01

Our previous work (E. Shedletzky, M. Shmuel, D.P. Delmer, D.T.A. Lamport [1990] Plant Physiol 94:980-987) showed that suspension-cultured tomato cells adapted to growth on the cellulose synthesis inhibitor 2,6-dichlorobenzonitrile (DCB) have a markedly altered cell wall composition, most notably a markedly reduced level of the cellulose-xyloglucan network. This study compares the adaptation to DCB of two cell lines from dicots (tomato [Lycopersicon esculentum] and tobacco [Nicotiana tabacum]) and a Graminaceous monocot (barley [Hordeum bulbosum] endosperm). The difference in wall structures between the dicots and the monocot is reflected in the very different types of wall modifications induced by growth on DCB. The dicots, having reduced levels of cellulose and xyloglucan, possess walls the major integrity of which is provided by Ca2+-bridged pectates because protoplasts can be prepared from these cells simply by treatment with divalent cation chelator and a purified endopolygalacturonase. The tensile strength of these walls is considerably less than walls from nonadapted cells, but wall porosity is not altered. In contrast, walls from adapted barley cells contain very little pectic material and normal to elevated levels of noncellulosic polysaccharides compared with walls from nonadapted cells. Surprisingly, they have tensile strengths higher than their nonadapted counterpart, although cellulose levels are reduced by 70%. Evidence is presented that these walls obtain their additional strength by an altered pattern of cross-linking of polymers involving phenolic components. Such cross-linking may also explain the observation that the porosity of these walls is also considerably reduced. Cells of adapted lines of both the dicots and barley are resistant to plasmolysis, suggesting that they possess very strong connections between the wall and the plasma membrane. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:16652933

Another Brick in the Wall: a Rhamnan Polysaccharide Trapped inside Peptidoglycan of Lactococcus lactis.

PubMed

Sadovskaya, Irina; Vinogradov, Evgeny; Courtin, Pascal; Armalyte, Julija; Meyrand, Mickael; Giaouris, Efstathios; Palussière, Simon; Furlan, Sylviane; Péchoux, Christine; Ainsworth, Stuart; Mahony, Jennifer; van Sinderen, Douwe; Kulakauskas, Saulius; Guérardel, Yann; Chapot-Chartier, Marie-Pierre

2017-09-12

Polysaccharides are ubiquitous components of the Gram-positive bacterial cell wall. In Lactococcus lactis , a polysaccharide pellicle (PSP) forms a layer at the cell surface. The PSP structure varies among lactococcal strains; in L. lactis MG1363, the PSP is composed of repeating hexasaccharide phosphate units. Here, we report the presence of an additional neutral polysaccharide in L. lactis MG1363 that is a rhamnan composed of α-l-Rha trisaccharide repeating units. This rhamnan is still present in mutants devoid of the PSP, indicating that its synthesis can occur independently of PSP synthesis. High-resolution magic-angle spinning nuclear magnetic resonance (HR-MAS NMR) analysis of whole bacterial cells identified a PSP at the surface of wild-type cells. In contrast, rhamnan was detected only at the surface of PSP-negative mutant cells, indicating that rhamnan is located underneath the surface-exposed PSP and is trapped inside peptidoglycan. The genetic determinants of rhamnan biosynthesis appear to be within the same genetic locus that encodes the PSP biosynthetic machinery, except the gene tagO encoding the initiating glycosyltransferase. We present a model of rhamnan biosynthesis based on an ABC transporter-dependent pathway. Conditional mutants producing reduced amounts of rhamnan exhibit strong morphological defects and impaired division, indicating that rhamnan is essential for normal growth and division. Finally, a mutation leading to reduced expression of lcpA , encoding a protein of the LytR-CpsA-Psr (LCP) family, was shown to severely affect cell wall structure. In lcpA mutant cells, in contrast to wild-type cells, rhamnan was detected by HR-MAS NMR, suggesting that LcpA participates in the attachment of rhamnan to peptidoglycan. IMPORTANCE In the cell wall of Gram-positive bacteria, the peptidoglycan sacculus is considered the major structural component, maintaining cell shape and integrity. It is decorated with other glycopolymers, including polysaccharides, the roles of which are not fully elucidated. In the ovococcus Lactococcus lactis , a polysaccharide with a different structure between strains forms a layer at the bacterial surface and acts as the receptor for various bacteriophages that typically exhibit a narrow host range. The present report describes the identification of a novel polysaccharide in the L. lactis cell wall, a rhamnan that is trapped inside the peptidoglycan and covalently bound to it. We propose a model of rhamnan synthesis based on an ABC transporter-dependent pathway. Rhamnan appears as a conserved component of the lactococcal cell wall playing an essential role in growth and division, thus highlighting the importance of polysaccharides in the cell wall integrity of Gram-positive ovococci. Copyright © 2017 Sadovskaya et al.

A laser microsurgical method of cell wall removal allows detection of large-conductance ion channels in the guard cell plasma membrane

NASA Technical Reports Server (NTRS)

Miedema, H.; Henriksen, G. H.; Assmann, S. M.; Evans, M. L. (Principal Investigator)

1999-01-01

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. "Laser-assisted" patch clamping reveals a new category of high-conductance (130 to 361 pS) ion channels not previously reported in patch clamp studies on plant plasma membranes. 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.

Cell wall layers delimit cell groups derived from cell division in the foliose trebouxiophycean alga Prasiola japonica.

PubMed

Mine, Ichiro; Kinoshita, Urara; Kawashima, Shigetaka; Sekida, Satoko

2018-01-22

The cells in the foliose thallus of trebouxiophycean alga Prasiola japonica apparently develop into 2 × 2 cell groups composed of two two-celled groups, each of which is a pair of derivative cells of the latest cell division. In the present study, the structural features of cell walls of the alga P. japonica concerning the formation of the cell groups were investigated using histochemical methods. Thin cell layers stained by Calcofluor White appeared to envelope the two-celled and four-celled groups separately and, hence, separated them from neighboring cell groups, and the Calcofluor White-negative gaps between neighboring four-celled groups were specifically stained by lectins, such as soybean agglutinin, jacalin, and Vicia villosa lectin conjugated with fluorescein. These results indicated that the Calcofluor White-positive cell wall layer of parent cell that existed during two successive cell divisions structurally distinguished two-celled and four-celled groups from others in this alga. Moreover, the results suggested that the cell wall components of the Calcofluor White-negative gaps would possibly contribute to the formation of the planar thallus through lateral union of the cell groups.

Saccharomyces cerevisiae cell wall components as tools for ochratoxin a decontamination.

PubMed

Piotrowska, Małgorzata; Masek, Anna

2015-04-02

The aim of this study was to evaluate the usefulness of Saccharomyces cerevisiae cell wall preparations in the adsorption of ochratoxin A (OTA). The study involved the use of a brewer's yeast cell wall devoid of protein substances, glucans obtained by water and alkaline extraction, a glucan commercially available as a dietary supplement for animals and, additionally, dried brewer's yeast for comparison. Fourier Transform Infrared (FTIR) analysis of the obtained preparations showed bands characteristic for glucans in the resulting spectra. The yeast cell wall preparation, water-extracted glucan and the commercial glucan bound the highest amount of ochratoxin A, above 55% of the initial concentration, and the alkaline-extracted glucan adsorbed the lowest amount of this toxin. It has been shown that adsorption is most effective at a close-to-neutral pH, while being considerably limited in alkaline conditions.

Enzyme Amplified Detection of Microbial Cell Wall Components

NASA Technical Reports Server (NTRS)

Wainwright, Norman R.

2004-01-01

This proposal is MBL's portion of NASA's Johnson Space Center's Astrobiology Center led by Principal Investigator, Dr. David McKay, entitled: 'Institute for the Study of Biomarkers in Astromaterials.' Dr. Norman Wainwright is the principal investigator at MBL and is responsible for developing methods to detect trace quantities of microbial cell wall chemicals using the enzyme amplification system of Limulus polyphemus and other related methods.

Chemical Synthesis of Oligosaccharides Related to the Cell Walls of Plants and Algae.

PubMed

Kinnaert, Christine; Daugaard, Mathilde; Nami, Faranak; Clausen, Mads H

2017-09-13

Plant cell walls are composed of an intricate network of polysaccharides and proteins that varies during the developmental stages of the cell. This makes it very challenging to address the functions of individual wall components in cells, especially for highly complex glycans. Fortunately, structurally defined oligosaccharides can be used as models for the glycans, to study processes such as cell wall biosynthesis, polysaccharide deposition, protein-carbohydrate interactions, and cell-cell adhesion. Synthetic chemists have focused on preparing such model compounds, as they can be produced in good quantities and with high purity. This Review contains an overview of those plant and algal polysaccharides that have been elucidated to date. The majority of the content is devoted to detailed summaries of the chemical syntheses of oligosaccharide fragments of cellulose, hemicellulose, pectin, and arabinogalactans, as well as glycans unique to algae. Representative synthetic routes within each class are discussed in detail, and the progress in carbohydrate chemistry over recent decades is highlighted.

Plant-based foods containing cell wall polysaccharides rich in specific active monosaccharides protect against myocardial injury in rat myocardial infarction models.

PubMed

Lim, Sun Ha; Kim, Yaesil; Yun, Ki Na; Kim, Jin Young; Jang, Jung-Hee; Han, Mee-Jung; Lee, Jongwon

2016-12-08

Many cohort studies have shown that consumption of diets containing a higher composition of foods derived from plants reduces mortality from coronary heart disease (CHD). Here, we examined the active components of a plant-based diet and the underlying mechanisms that reduce the risk of CHD using three rat models and a quantitative proteomics approach. In a short-term myocardial infarction (MI) model, intake of wheat extract (WE), the representative cardioprotectant identified by screening approximately 4,000 samples, reduced myocardial injury by inhibiting apoptosis, enhancing ATP production, and maintaining protein homeostasis. In long-term post-MI models, this myocardial protection resulted in ameliorating adverse left-ventricular remodelling, which is a predictor of heart failure. Among the wheat components, arabinose and xylose were identified as active components responsible for the observed efficacy of WE, which was administered via ingestion and tail-vein injections. Finally, the food components of plant-based diets that contained cell wall polysaccharides rich in arabinose, xylose, and possibly fucose were found to confer protection against myocardial injury. These results show for the first time that specific monosaccharides found in the cell wall polysaccharides in plant-based diets can act as active ingredients that reduce CHD by inhibiting postocclusion steps, including MI and heart failure.

The ng_ζ1 toxin of the gonococcal epsilon/zeta toxin/antitoxin system drains precursors for cell wall synthesis.

PubMed

Rocker, Andrea; Peschke, Madeleine; Kittilä, Tiia; Sakson, Roman; Brieke, Clara; Meinhart, Anton

2018-04-27

Bacterial toxin-antitoxin complexes are emerging as key players modulating bacterial physiology as activation of toxins induces stasis or programmed cell death by interference with vital cellular processes. Zeta toxins, which are prevalent in many bacterial genomes, were shown to interfere with cell wall formation by perturbing peptidoglycan synthesis in Gram-positive bacteria. Here, we characterize the epsilon/zeta toxin-antitoxin (TA) homologue from the Gram-negative pathogen Neisseria gonorrhoeae termed ng_ɛ1 / ng_ζ1. Contrary to previously studied streptococcal epsilon/zeta TA systems, ng_ɛ1 has an epsilon-unrelated fold and ng_ζ1 displays broader substrate specificity and phosphorylates multiple UDP-activated sugars that are precursors of peptidoglycan and lipopolysaccharide synthesis. Moreover, the phosphorylation site is different from the streptococcal zeta toxins, resulting in a different interference with cell wall synthesis. This difference most likely reflects adaptation to the individual cell wall composition of Gram-negative and Gram-positive organisms but also the distinct involvement of cell wall components in virulence.

Utilization of non-conventional systems for conversion of biomass to food components: Potential for utilization of algae in engineered foods

NASA Technical Reports Server (NTRS)

Karel, M.; Kamarei, A. R.; Nakhost, Z.

1985-01-01

The major nutritional components of the green algae (Scenedesmus obliquus) grown in a Constant Cell density Apparatus were determined. Suitable methodology to prepare proteins from which three major undesirable components of these cells (i.e., cell walls, nucleic acids, and pigments) were either removed or substantially reduced was developed. Results showed that processing of green algae to protein isolate enhances its potential nutritional and organoleptic acceptability as a diet component in a Controlled Ecological Life Support System.

Oxidative and antioxidative responses in the wheat-Azospirillum brasilense interaction.

PubMed

Méndez-Gómez, Manuel; Castro-Mercado, Elda; Alexandre, Gladys; García-Pineda, Ernesto

2016-03-01

Azospirillum is a plant growth-promoting rhizobacteria (PGPR) able to enhance the growth of wheat. The aim of this study was to test the effect of Azospirillum brasilense cell wall components on superoxide (O2·(-)) production in wheat roots and the effect of oxidative stress on A. brasilense viability. We found that inoculation with A. brasilense reduced O2·(-) levels by approx. 30 % in wheat roots. Inoculation of wheat with papain-treated A. brasilense, a Cys protease, notably increased O2·(-) production in all root tissues, as was observed by the nitro blue tetrazolium (NBT) reduction. However, a 24-h treatment with rhizobacteria lipopolysaccharides (50 and 100 μg/mL) alone did not affect the pattern of O2·(-) production. Analysis of the effect of plant cell wall components on A. brasilense oxidative enzyme activity showed no changes in catalase activity but a decrease in superoxide dismutase activity in response to polygalacturonic acid treatment. Furthermore, A. brasilense growth was only affected by high concentrations of H2O2 or paraquat, but not by sodium nitroprusside. Our results suggest that rhizobacterial cell wall components play an important role in controlling plant cell responses and developing tolerance of A. brasilense to oxidative stress produced by the plant.

Transcription of thymic stromal lymphopoietin via Toll-like receptor 2 in canine keratinocytes: a possible association of Staphylococcus spp. in the deterioration of allergic inflammation in canine atopic dermatitis.

PubMed

Sakamoto, Mayu; Asahina, Ryota; Kamishina, Hiroaki; Maeda, Sadatoshi

2016-06-01

Colonization, overgrowth and subsequent infection by Staphylococcus spp. is frequently observed in canine atopic dermatitis (CAD), where it contributes to the intensity of cutaneous inflammation. The mechanisms by which staphylococci contribute to the pathogenesis of CAD are unclear. Studies suggest that thymic stromal lymphopoietin (TSLP), a cytokine induced by a cell wall component of Staphylococcus spp., may play a critical role in Th2 responses including the pathogenesis of CAD. To determine if synthetic triacylated lipopeptide (TLR1/2 ligand), a cell wall component of Staphylococcus spp., induces the transcription of TSLP via TLR2 in canine keratinocytes. Transcription of TSLP was quantified in a canine keratinocyte cell line after stimulation with synthetic triacylated lipopeptide, and again after inhibition of TLR2 by a targeted small interfering RNA. The transcription of TSLP was enhanced 6 h after stimulation with the synthetic triacylated lipopeptide; it was completely suppressed by knockdown of TLR2. The results demonstrated that a synthetic cell wall component of Staphylococcus spp. induced transcription of TSLP via TLR2 in canine keratinocytes. Additional studies will be required to investigate whether Staphylococcus spp. contributes to Th2 responses in CAD through TLR2-mediated TSLP production. © 2016 ESVD and ACVD.

Thermal management system and method for a solid-state energy storing device

DOEpatents

Rouillard, Roger; Domroese, Michael K.; Gauthier, Michel; Hoffman, Joseph A.; Lindeman, David D.; Noel, Joseph-Robert-Gaetan; Radewald, Vern E.; Ranger, Michel; Rouillard, Jean; Shiota, Toshimi; St-Germain, Philippe; Sudano, Anthony; Trice, Jennifer L.; Turgeon, Thomas A.

2000-01-01

An improved electrochemical energy storing device includes a number of thin-film electrochemical cells which are maintained in a state of compression through use of an internal or an external pressure apparatus. A thermal conductor, which is connected to at least one of the positive or negative contacts of each electrochemical cell, conducts current into and out of the electrochemical cells and also conducts thermal energy between the electrochemical cells and thermally conductive material disposed on a wall structure adjacent the conductors. The wall structure includes electrically resistive material, such as an anodized coating or a thin film of plastic. The thermal conductors are fabricated to include a spring mechanism which expands and contacts to maintain mechanical contact between the electrochemical cells and the thermally conductive material in the presence of relative movement between the electrochemical cells and the wall structure. An active cooling apparatus may be employed external to a hermetically sealed housing containing the electrochemical cells to enhance the transfer of thermal energy into and out of the electrochemical cells. An integrated interconnect board may be disposed within the housing onto which a number of electrical and electro-mechanical components are mounted. Heat generated by the components is conducted from the interconnect board to the housing using the thermal conductors.

Transcriptomic insights into citrus segment membrane's cell wall components relating to fruit sensory texture.

PubMed

Wang, Xun; Lin, Lijin; Tang, Yi; Xia, Hui; Zhang, Xiancong; Yue, Maolan; Qiu, Xia; Xu, Ke; Wang, Zhihui

2018-04-23

During fresh fruit consumption, sensory texture is one factor that affects the organoleptic qualities. Chemical components of plant cell walls, including pectin, cellulose, hemicellulose and lignin, play central roles in determining the textural qualities. To explore the genes and regulatory pathways involved in fresh citrus' perceived sensory texture, we performed mRNA-seq analyses of the segment membranes of two citrus cultivars, Shiranui and Kiyomi, with different organoleptic textures. Segment membranes were sampled at two developmental stages of citrus fruit, the beginning and end of the expansion period. More than 3000 differentially expressed genes were identified. The gene ontology analysis revealed that more categories were significantly enriched in 'Shiranui' than in 'Kiyomi' at both developmental stages. In total, 108 significantly enriched pathways were obtained, with most belonging to metabolism. A detailed transcriptomic analysis revealed potential critical genes involved in the metabolism of cell wall structures, for example, GAUT4 in pectin synthesis, CESA1, 3 and 6, and SUS4 in cellulose synthesis, CSLC5, XXT1 and XXT2 in hemicellulose synthesis, and CSE in lignin synthesis. Low levels, or no expression, of genes involved in cellulose and hemicellulose, such as CESA4, CESA7, CESA8, IRX9 and IRX14, confirmed that secondary cell walls were negligible or absent in citrus segment membranes. A chemical component analysis of the segment membranes from mature fruit revealed that the pectin, cellulose and lignin contents, and the segment membrane's weight (% of segment) were greater in 'Kiyomi'. Organoleptic quality of citrus is easily overlooked. It is mainly determined by sensory texture perceived in citrus segment membrane properties. We performed mRNA-seq analyses of citrus segment membranes to explore the genes and regulatory pathways involved in fresh citrus' perceived sensory texture. Transcriptomic data showed high repeatability between two independent biological replicates. The expression levels of genes involved in cell wall structure metabolism, including pectin, cellulose, hemicellulose and lignin, were investigated. Meanwhile, chemical component contents of the segment membranes from mature fruit were analyzed. This study provided detailed transcriptional regulatory profiles of different organoleptic citrus qualities and integrated insights into the mechanisms affecting citrus' sensory texture.

Characterizing visible and invisible cell wall mutant phenotypes.

PubMed

Carpita, Nicholas C; McCann, Maureen C

2015-07-01

About 10% of a plant's genome is devoted to generating the protein machinery to synthesize, remodel, and deconstruct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with 'invisible' phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basis of deviation from the wild type in genetic functional analyses to insights provided by modern analytical techniques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide components of the plant cell wall. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Chemical Organization of the Cell Wall Polysaccharide Core of Malassezia restricta

PubMed Central

Stalhberger, Thomas; Simenel, Catherine; Clavaud, Cécile; Eijsink, Vincent G. H.; Jourdain, Roland; Delepierre, Muriel; Latgé, Jean-Paul; Breton, Lionel; Fontaine, Thierry

2014-01-01

Malassezia species are ubiquitous residents of human skin and are associated with several diseases such as seborrheic dermatitis, tinea versicolor, folliculitis, atopic dermatitis, and scalp conditions such as dandruff. Host-Malassezia interactions and mechanisms to evade local immune responses remain largely unknown. Malassezia restricta is one of the most predominant yeasts of the healthy human skin, its cell wall has been investigated in this paper. Polysaccharides in the M. restricta cell wall are almost exclusively alkali-insoluble, showing that they play an essential role in the organization and rigidity of the M. restricta cell wall. Fractionation of cell wall polymers and carbohydrate analyses showed that the polysaccharide core of the cell wall of M. restricta contained an average of 5% chitin, 20% chitosan, 5% β-(1,3)-glucan, and 70% β-(1,6)-glucan. In contrast to other yeasts, chitin and chitosan are relatively abundant, and β-(1,3)-glucans constitute a minor cell wall component. The most abundant polymer is β-(1,6)-glucans, which are large molecules composed of a linear β-(1,6)-glucan chains with β-(1,3)-glucosyl side chain with an average of 1 branch point every 3.8 glucose unit. Both β-glucans are cross-linked, forming a huge alkali-insoluble complex with chitin and chitosan polymers. Data presented here show that M. restricta has a polysaccharide organization very different of all fungal species analyzed to date. PMID:24627479

Chemical organization of the cell wall polysaccharide core of Malassezia restricta.

PubMed

Stalhberger, Thomas; Simenel, Catherine; Clavaud, Cécile; Eijsink, Vincent G H; Jourdain, Roland; Delepierre, Muriel; Latgé, Jean-Paul; Breton, Lionel; Fontaine, Thierry

2014-05-02

Malassezia species are ubiquitous residents of human skin and are associated with several diseases such as seborrheic dermatitis, tinea versicolor, folliculitis, atopic dermatitis, and scalp conditions such as dandruff. Host-Malassezia interactions and mechanisms to evade local immune responses remain largely unknown. Malassezia restricta is one of the most predominant yeasts of the healthy human skin, its cell wall has been investigated in this paper. Polysaccharides in the M. restricta cell wall are almost exclusively alkali-insoluble, showing that they play an essential role in the organization and rigidity of the M. restricta cell wall. Fractionation of cell wall polymers and carbohydrate analyses showed that the polysaccharide core of the cell wall of M. restricta contained an average of 5% chitin, 20% chitosan, 5% β-(1,3)-glucan, and 70% β-(1,6)-glucan. In contrast to other yeasts, chitin and chitosan are relatively abundant, and β-(1,3)-glucans constitute a minor cell wall component. The most abundant polymer is β-(1,6)-glucans, which are large molecules composed of a linear β-(1,6)-glucan chains with β-(1,3)-glucosyl side chain with an average of 1 branch point every 3.8 glucose unit. Both β-glucans are cross-linked, forming a huge alkali-insoluble complex with chitin and chitosan polymers. Data presented here show that M. restricta has a polysaccharide organization very different of all fungal species analyzed to date.

Effect of microgravity on plant growth

NASA Technical Reports Server (NTRS)

Lewis, Norman G.

1994-01-01

The overall goal of this research is to determine the effect of microgravity proper on plant growth (metabolism and cell wall formation). In addressing this goal, the work conducted during this grant period was divided into three components: analyses of various plant tissues previously grown in space aboard MIR Space Station; analyses of wheat tissues grown on Shuttle flight STS-51; and Phenylpropanoid metabolism and plant cell wall synthesis (earth-based investigations).

Small angle neutron scattering as a tool to evaluate moisture-induced swelling in the nanostructure of chemically modified wood cell walls

Treesearch

Nayomi Z. Plaza; Joseph E. Jakes; Charles R. Frihart; Christopher G. Hunt; Daniel J. Yelle; Linda F. Lorenz

2017-01-01

Wood-based products can be a sustainable and more environmentally friendly alternative to traditional construction materials because of their reduced contribution to air and water pollution. An integral component of these products is often an adhesive. Because wood is hygroscopic, moisture-induced swelling in the cell walls near the wood– adhesive bondlines can lead to...

Pectin and the role of the physical properties of the cell wall in pollen tube growth of Solanum chacoense.

PubMed

Parre, Elodie; Geitmann, Anja

2005-02-01

The cell wall is one of the structural key players regulating pollen tube growth, since plant cell expansion depends on an interplay between intracellular driving forces and the controlled yielding of the cell wall. Pectin is the main cell wall component at the growing pollen tube apex. We therefore assessed its role in pollen tube growth and cytomechanics using the enzymes pectinase and pectin methyl esterase (PME). Pectinase activity was able to stimulate pollen germination and tube growth at moderate concentrations whereas higher concentrations caused apical swelling or bursting in Solanum chacoense Bitt. pollen tubes. This is consistent with a modification of the physical properties of the cell wall affecting its extensibility and thus the growth rate, as well as its capacity to withstand turgor. To prove that the enzyme-induced effects were due to the altered cell wall mechanics, we subjected pollen tubes to micro-indentation experiments. We observed that cellular stiffness was reduced and visco-elasticity increased in the presence of pectinase. These are the first mechanical data that confirm the influence of the amount of pectins in the pollen tube cell wall on the physical parameters characterizing overall cellular architecture. Cytomechanical data were also obtained to analyze the role of the degree of pectin methyl-esterification, which is known to exhibit a gradient along the pollen tube axis. This feature has frequently been suggested to result in a gradient of the physical properties characterizing the cell wall and our data provide, for the first time, mechanical support for this concept. The gradient in cell wall composition from apical esterified to distal de-esterified pectins seems to be correlated with an increase in the degree of cell wall rigidity and a decrease of visco-elasticity. Our mechanical approach provides new insights concerning the mechanics of pollen tube growth and the architecture of living plant cells.

Cellular growth in plants requires regulation of cell wall biochemistry.

PubMed

Chebli, Youssef; Geitmann, Anja

2017-02-01

Cell and organ morphogenesis in plants are regulated by the chemical structure and mechanical properties of the extracellular matrix, the cell wall. The two primary load bearing components in the plant cell wall, the pectin matrix and the cellulose/xyloglucan network, are constantly remodelled to generate the morphological changes required during plant development. This remodelling is regulated by a plethora of loosening and stiffening agents such as pectin methyl-esterases, calcium ions, expansins, and glucanases. The tight spatio-temporal regulation of the activities of these agents is a sine qua non condition for proper morphogenesis at cell and tissue levels. The pectin matrix and the cellulose-xyloglucan network operate in concert and their behaviour is mutually dependent on their chemical, structural and mechanical modifications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Improvement in Saccharification Yield of Mixed Rumen Enzymes by Identification of Recalcitrant Cell Wall Constituents Using Enzyme Fingerprinting.

PubMed

Badhan, Ajay; Wang, Yu-Xi; Gruninger, Robert; Patton, Donald; Powlowski, Justin; Tsang, Adrian; McAllister, Tim A

2015-01-01

Identification of recalcitrant factors that limit digestion of forages and the development of enzymatic approaches that improve hydrolysis could play a key role in improving the efficiency of meat and milk production in ruminants. Enzyme fingerprinting of barley silage fed to heifers and total tract indigestible fibre residue (TIFR) collected from feces was used to identify cell wall components resistant to total tract digestion. Enzyme fingerprinting results identified acetyl xylan esterases as key to the enhanced ruminal digestion. FTIR analysis also suggested cross-link cell wall polymers as principal components of indigested fiber residues in feces. Based on structural information from enzymatic fingerprinting and FTIR, enzyme pretreatment to enhance glucose yield from barley straw and alfalfa hay upon exposure to mixed rumen-enzymes was developed. Prehydrolysis effects of recombinant fungal fibrolytic hydrolases were analyzed using microassay in combination with statistical experimental design. Recombinant hemicellulases and auxiliary enzymes initiated degradation of plant structural polysaccharides upon application and improved the in vitro saccharification of alfalfa and barley straw by mixed rumen enzymes. The validation results showed that microassay in combination with statistical experimental design can be successfully used to predict effective enzyme pretreatments that can enhance plant cell wall digestion by mixed rumen enzymes.

Distribution of polycyclic aromatic hydrocarbons in subcellular root tissues of ryegrass (Lolium multiflorum Lam.)

PubMed Central

2010-01-01

Background Because of the increasing quantity and high toxicity to humans of polycyclic aromatic hydrocarbons (PAHs) in the environment, several bioremediation mechanisms and protocols have been investigated to restore PAH-contaminated sites. The transport of organic contaminants among plant cells via tissues and their partition in roots, stalks, and leaves resulting from transpiration and lipid content have been extensively investigated. However, information about PAH distributions in intracellular tissues is lacking, thus limiting the further development of a mechanism-based phytoremediation strategy to improve treatment efficiency. Results Pyrene exhibited higher uptake and was more recalcitrant to metabolism in ryegrass roots than was phenanthrene. The kinetic processes of uptake from ryegrass culture medium revealed that these two PAHs were first adsorbed onto root cell walls, and they then penetrated cell membranes and were distributed in intracellular organelle fractions. At the beginning of uptake (< 50 h), adsorption to cell walls dominated the subcellular partitioning of the PAHs. After 96 h of uptake, the subcellular partition of PAHs approached a stable state in the plant water system, with the proportion of PAH distributed in subcellular fractions being controlled by the lipid contents of each component. Phenanthrene and pyrene primarily accumulated in plant root cell walls and organelles, with about 45% of PAHs in each of these two fractions, and the remainder was retained in the dissolved fraction of the cells. Because of its higher lipophilicity, pyrene displayed greater accumulation factors in subcellular walls and organelle fractions than did phenanthrene. Conclusions Transpiration and the lipid content of root cell fractions are the main drivers of the subcellular partition of PAHs in roots. Initially, PAHs adsorb to plant cell walls, and they then gradually diffuse into subcellular fractions of tissues. The lipid content of intracellular components determines the accumulation of lipophilic compounds, and the diffusion rate is related to the concentration gradient established between cell walls and cell organelles. Our results offer insights into the transport mechanisms of PAHs in ryegrass roots and their diffusion in root cells. PMID:20860818

Relevance, structure and analysis of ferulic acid in maize cell walls.

PubMed

Bento-Silva, Andreia; Vaz Patto, Maria Carlota; do Rosário Bronze, Maria

2018-04-25

Phenolic compounds in foods have been widely studied due to their health benefits. In cereals, phenolic compounds are extensively linked to cell wall polysaccharides, mainly arabinoxylans, which cross-link with each other and with other cell wall components. In maize, ferulic acid is the phenolic acid present in the highest concentration, forming ferulic acid dehydrodimers, trimers and tetramers. The cross-linking of polysaccharides is important for the cell wall structure and growth, and may protect against pathogen invasion. In addition to the importance for maize physiology, ferulic acid has been recognized as an important chemical structure with a wide range of health benefits when consumed in a diet rich in fibre. This review paper presents the different ways ferulic acid can be present in maize, the importance of ferulic acid derivatives and the methodologies that can be used for their analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Saccharomyces Cerevisiae Cell Wall Components as Tools for Ochratoxin A Decontamination

PubMed Central

Piotrowska, Małgorzata; Masek, Anna

2015-01-01

The aim of this study was to evaluate the usefulness of Saccharomyces cerevisiae cell wall preparations in the adsorption of ochratoxin A (OTA). The study involved the use of a brewer’s yeast cell wall devoid of protein substances, glucans obtained by water and alkaline extraction, a glucan commercially available as a dietary supplement for animals and, additionally, dried brewer’s yeast for comparison. Fourier Transform Infrared (FTIR) analysis of the obtained preparations showed bands characteristic for glucans in the resulting spectra. The yeast cell wall preparation, water-extracted glucan and the commercial glucan bound the highest amount of ochratoxin A, above 55% of the initial concentration, and the alkaline-extracted glucan adsorbed the lowest amount of this toxin. It has been shown that adsorption is most effective at a close-to-neutral pH, while being considerably limited in alkaline conditions. PMID:25848694

Peptidoglycan and Teichoic Acid Levels and Alterations in Staphylococcus aureus by Cell-Wall and Whole-Cell Nuclear Magnetic Resonance.

PubMed

Romaniuk, Joseph A H; Cegelski, Lynette

2018-06-11

Gram-positive bacteria surround themselves with a multilayered macromolecular cell wall that is essential to cell survival and serves as a major target for antibiotics. The cell wall of Staphylococcus aureus is composed of two major structural components, peptidoglycan (PG) and wall teichoic acid (WTA), together creating a heterogeneous and insoluble matrix that poses a challenge to quantitative compositional analysis. Here, we present 13 C cross polarization magic angle spinning solid-state nuclear magnetic resonance (NMR) spectra of intact cell walls, purified PG, and purified WTA. The spectra reveal the clear molecular differences in the two polymers and enable quantification of PG and WTA in isolated cell walls, an attractive alternative to estimating teichoic acid content from a phosphate analysis of completely pyrolyzed cell walls. Furthermore, we discovered that unique PG and WTA spectral signatures could be identified in whole-cell NMR spectra and used to compare PG and WTA levels among intact bacterial cell samples. The distinguishing whole-cell 13 C NMR contributions associated with PG include the GlcNAc-MurNAc sugar carbons and glycyl α-carbons. WTA contributes carbons from the phosphoribitol backbone. Distinguishing 15 N spectral signatures include glycyl amide nitrogens in PG and the esterified d-alanyl amine nitrogens in WTA. 13 C NMR analysis was performed with samples at natural abundance and included 10 whole-cell sample comparisons. Changes consistent with altered PG and WTA content were detected in whole-cell spectra of bacteria harvested at different growth times and in cells treated with tunicamycin. This use of whole-cell NMR provides quantitative parameters of composition in the context of whole-cell activity.

Surfaceome and Proteosurfaceome in Parietal Monoderm Bacteria: Focus on Protein Cell-Surface Display

PubMed Central

Desvaux, Mickaël; Candela, Thomas; Serror, Pascale

2018-01-01

The cell envelope of parietal monoderm bacteria (archetypal Gram-positive bacteria) is formed of a cytoplasmic membrane (CM) and a cell wall (CW). While the CM is composed of phospholipids, the CW is composed at least of peptidoglycan (PG) covalently linked to other biopolymers, such as teichoic acids, polysaccharides, and/or polyglutamate. Considering the CW is a porous structure with low selective permeability contrary to the CM, the bacterial cell surface hugs the molecular figure of the CW components as a well of the external side of the CM. While the surfaceome corresponds to the totality of the molecules found at the bacterial cell surface, the proteinaceous complement of the surfaceome is the proteosurfaceome. Once translocated across the CM, secreted proteins can either be released in the extracellular milieu or exposed at the cell surface by associating to the CM or the CW. Following the gene ontology (GO) for cellular components, cell-surface proteins at the CM can either be integral (GO: 0031226), i.e., the integral membrane proteins, or anchored to the membrane (GO: 0046658), i.e., the lipoproteins. At the CW (GO: 0009275), cell-surface proteins can be covalently bound, i.e., the LPXTG-proteins, or bound through weak interactions to the PG or wall polysaccharides, i.e., the cell wall binding proteins. Besides monopolypeptides, some proteins can associate to each other to form supramolecular protein structures of high molecular weight, namely the S-layer, pili, flagella, and cellulosomes. After reviewing the cell envelope components and the different molecular mechanisms involved in protein attachment to the cell envelope, perspectives in investigating the proteosurfaceome in parietal monoderm bacteria are further discussed. PMID:29491848

Cross-stream distribution of red blood cells in sickle-cell disease

NASA Astrophysics Data System (ADS)

Zhang, Xiao; Lam, Wilbur; Graham, Michael

2017-11-01

Experiments revealed that in blood flow, red blood cells (RBCs) tend to migrate away from the vessel walls, leaving a cell-free layer near the walls, while leukocytes and platelets tend to marginate towards the vessel walls. This segregation behavior of different cellular components in blood flow can be driven by their differences in stiffness and shape. An alteration of this segregation behavior may explain endothelial dysfunction and pain crisis associated with sickle-cell disease (SCD). It is hypothesized that the sickle RBCs, which are considerably stiffer than the healthy RBCs, may marginate towards the vessel walls and exert repeated damage to the endothelial cells. Direct simulations are performed to study the flowing suspensions of deformable biconcave discoids and stiff sickles representing healthy and sickle cells, respectively. It is observed that the sickles exhibit a strong margination towards the walls. The biconcave discoids in flowing suspensions undergo a so-called tank-treading motion, while the sickles behave as rigid bodies and undergo a tumbling motion. The margination behavior and tumbling motion of the sickles may help substantiate the aforementioned hypothesis of the mechanism for the SCD complications and shed some light on the design of novel therapies.

13C cell wall enrichment and ionic liquid NMR analysis: progress towards a high-throughput detailed chemical analysis of the whole plant cell wall.

PubMed

Foston, Marcus; Samuel, Reichel; Ragauskas, Arthur J

2012-09-07

The ability to accurately and rapidly measure plant cell wall composition, relative monolignol content and lignin-hemicellulose inter-unit linkage distributions has become essential to efforts centered on reducing the recalcitrance of biomass by genetic engineering. Growing (13)C enriched transgenic plants is a viable route to achieve the high-throughput, detailed chemical analysis of whole plant cell wall before and after pretreatment and microbial or enzymatic utilization by (13)C nuclear magnetic resonance (NMR) in a perdeuterated ionic liquid solvent system not requiring component isolation. 1D (13)C whole cell wall ionic liquid NMR of natural abundant and (13)C enriched corn stover stem samples suggest that a high level of uniform labeling (>97%) can significantly reduce the total NMR experiment times up to ~220 times. Similarly, significant reduction in total NMR experiment time (~39 times) of the (13)C enriched corn stover stem samples for 2D (13)C-(1)H heteronuclear single quantum coherence NMR was found.

The role of endoxyloglucan transferase in the organization of plant cell walls.

PubMed

Nishitani, K

1997-01-01

The plant cell wall plays a central role in morphogenesis as well as responsiveness to environmental signals. Xyloglucans are the principal component of the plant cell wall matrix and serve as cross-links between cellulose microfibrils to form the cellulose-xyloglucan framework. Endoxyloglucan transferase (EXGT), which was isolated and characterized in 1992, is an enzyme that mediates molecular grafting reaction between xyloglucan molecules. Structural studies on cDNAs encoding EXGT and its related proteins have disclosed the ubiquitous presence in the plant kingdom of a large multigene family of xyloglucan-related proteins (XRPs). Each XRP functions as either hydrolase or transferase acting on xyloglucans and is considered to be responsible for rearrangement of the cellulose-xyloglucan framework, the processes essential for the construction, modification, and degradation of plant cell walls. Different XRP genes exhibit potentially different expression profiles with respect to tissue specificity and responsiveness to hormonal and mechanical signals. The molecular approach to individual XRP genes will open a new path for exploring the controlling mechanisms by which the plant cell wall is constructed and reformed during plant growth and development.

Soft buckling actuators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Dian; Whitesides, George M.

A soft actuator is described, including: a rotation center having a center of mass; a plurality of bucklable, elastic structural components each comprising a wall defining an axis along its longest dimension, the wall connected to the rotation center in a way that the axis is offset from the center of mass in a predetermined direction; and a plurality of cells each disposed between two adjacent bucklable, elastic structural components and configured for connection with a fluid inflation or deflation source; wherein upon the deflation of the cell, the bucklable, elastic structural components are configured to buckle in the predeterminedmore » direction. A soft actuating device including a plurality of the soft actuators and methods of actuation using the soft actuator or soft actuating device disclosed herein are also described.« less

Attachment of Salmonella strains to a plant cell wall model is modulated by surface characteristics and not by specific carbohydrate interactions.

PubMed

Tan, Michelle Sze-Fan; Moore, Sean C; Tabor, Rico F; Fegan, Narelle; Rahman, Sadequr; Dykes, Gary A

2016-09-15

Processing of fresh produce exposes cut surfaces of plant cell walls that then become vulnerable to human foodborne pathogen attachment and contamination, particularly by Salmonella enterica. Plant cell walls are mainly composed of the polysaccharides cellulose, pectin and hemicelluloses (predominantly xyloglucan). Our previous work used bacterial cellulose-based plant cell wall models to study the interaction between Salmonella and the various plant cell wall components. We demonstrated that Salmonella attachment was favoured in the presence of pectin while xyloglucan had no effect on its attachment. Xyloglucan significantly increased the attachment of Salmonella cells to the plant cell wall model only when it was in association with pectin. In this study, we investigate whether the plant cell wall polysaccharides mediate Salmonella attachment to the bacterial cellulose-based plant cell wall models through specific carbohydrate interactions or through the effects of carbohydrates on the physical characteristics of the attachment surface. We found that none of the monosaccharides that make up the plant cell wall polysaccharides specifically inhibit Salmonella attachment to the bacterial cellulose-based plant cell wall models. Confocal laser scanning microscopy showed that Salmonella cells can penetrate and attach within the tightly arranged bacterial cellulose network. Analysis of images obtained from atomic force microscopy revealed that the bacterial cellulose-pectin-xyloglucan composite with 0.3 % (w/v) xyloglucan, previously shown to have the highest number of Salmonella cells attached to it, had significantly thicker cellulose fibrils compared to other composites. Scanning electron microscopy images also showed that the bacterial cellulose and bacterial cellulose-xyloglucan composites were more porous when compared to the other composites containing pectin. Our study found that the attachment of Salmonella cells to cut plant cell walls was not mediated by specific carbohydrate interactions. This suggests that the attachment of Salmonella strains to the plant cell wall models were more dependent on the structural characteristics of the attachment surface. Pectin reduces the porosity and space between cellulose fibrils, which then forms a matrix that is able to retain Salmonella cells within the bacterial cellulose network. When present with pectin, xyloglucan provides a greater surface for Salmonella cells to attach through the thickening of cellulose fibrils.

The effects of Candida albicans cell wall protein fraction on dendritic cell maturation.

PubMed

Roudbary, Maryam; Roudbar Mohammadi, Shahla; Bozorgmehr, Mahmood; Moazzeni, Seyed Mohammad

2009-06-01

Candida albicans is a member of the normal human microflora. C. albicans cell wall is composed of several protein and carbohydrate components which have been shown to play a crucial role in C. albicans interaction with the host immune system. Major components of C. albican cell wall are carbohydrates such as mannans, beta glucans and chitins, and proteins that partially modulate the host immune responses. Dendritic cells (DC), as the most important antigen-presenting cells of the immune system, play a critical role in inducing immune responses against different pathogens. We investigated the effect of the cell wall protein fraction (CPF) of C. albicans on DC maturation. The CPF of C. albicans cells was extracted by a lysis buffer containing sodium dodecyl sulphate, 2-mercaptoethanol and phosphate-buffered saline. The extract was dialyzed and its protein pattern was evaluated by electrophoresis. Dendritic cells were purified from Balb/c mice spleens through a three-step method including mononuclear cell separation, as well as 2-h and overnight cultures. The purified CPF was added at different concentrations to DC. The purity and maturation status of DC were determined by flow cytometry using monoclonal antibodies against CD11c, MHC-II, CD40 and CD86. Treatment of DC with 10 microg/ml of CPF increased the expression of maturation markers including MHC-II, CD86 and CD40 on DC compared to the control group. In this study we used C. albicans CPF with the molecular weight of 40-45 kDa for pulsing and maturation of dendritic cells. Since according to our results CPF significantly increased the expression of maturation markers on DC, we suggest that CPF may act as an efficient immunomodulator, or may be used as a potential adjuvant to boost the host immune system against infections.

Histoplasma capsulatum α-(1,3)-glucan blocks innate immune recognition by the β-glucan receptor

PubMed Central

Rappleye, Chad A.; Eissenberg, Linda Groppe; Goldman, William E.

2007-01-01

Successful infection by fungal pathogens depends on subversion of host immune mechanisms that detect conserved cell wall components such as β-glucans. A less common polysaccharide, α-(1,3)-glucan, is a cell wall constituent of most fungal respiratory pathogens and has been correlated with pathogenicity or linked directly to virulence. However, the precise mechanism by which α-(1,3)-glucan promotes fungal virulence is unknown. Here, we show that α-(1,3)-glucan is present in the outermost layer of the Histoplasma capsulatum yeast cell wall and contributes to pathogenesis by concealing immunostimulatory β-glucans from detection by host phagocytic cells. Production of proinflammatory TNFα by phagocytes was suppressed either by the presence of the α-(1,3)-glucan layer on yeast cells or by RNA interference based depletion of the host β-glucan receptor dectin-1. Thus, we have functionally defined key molecular components influencing the initial host–pathogen interaction in histoplasmosis and have revealed an important mechanism by which H. capsulatum thwarts the host immune system. Furthermore, we propose that the degree of this evasion contributes to the difference in pathogenic potential between dimorphic fungal pathogens and opportunistic fungi. PMID:17227865

Imaging and Spectroscopy of Natural Fluorophores in Pine Needles

PubMed Central

Williams, Nari

2018-01-01

Many plant tissues fluoresce due to the natural fluorophores present in cell walls or within the cell protoplast or lumen. While lignin and chlorophyll are well-known fluorophores, other components are less well characterized. Confocal fluorescence microscopy of fresh or fixed vibratome-cut sections of radiata pine needles revealed the presence of suberin, lignin, ferulate, and flavonoids associated with cell walls as well as several different extractive components and chlorophyll within tissues. Comparison of needles in different physiological states demonstrated the loss of chlorophyll in both chlorotic and necrotic needles. Necrotic needles showed a dramatic change in the fluorescence of extractives within mesophyll cells from ultraviolet (UV) excited weak blue fluorescence to blue excited strong green fluorescence associated with tissue browning. Comparisons were made among fluorophores in terms of optimal excitation, relative brightness compared to lignin, and the effect of pH of mounting medium. Fluorophores in cell walls and extractives in lumens were associated with blue or green emission, compared to the red emission of chlorophyll. Autofluorescence is, therefore, a useful method for comparing the histology of healthy and diseased needles without the need for multiple staining techniques, potentially aiding visual screening of host resistance and disease progression in needle tissue. PMID:29393922

Pectin-like carbohydrates in the green alga Micrasterias characterized by cytochemical analysis and energy filtering TEM.

PubMed

Eder, M; Lütz-Meindl, U

2008-08-01

Pectins are the major matrix polysaccharides of plant cell walls and are important for controlling growth, wall porosity and regulation of the ionic environment in plant cells. Pectic epitopes recognized by the monoclonal antibodies JIM5, JIM7 and 2F4 could be localized in the primary wall during development of the green alga Micrasterias. As the degree of pectin esterification determines the calcium-binding capacity and thus the physical properties of the cell wall, chemical and enzymatic in situ de-esterification was performed. This resulted in displacement of epitopes recognized by JIM5, JIM7 and 2F4, respectively, in changes in the intensity of the antibody labelling as visualized in CLSM. In addition, calcium-binding capacities of cell walls and components of the secretory apparatus were determined in transmission electron microscopy by electron energy loss spectroscopy and electron spectroscopic imaging. These analyses revealed that pectic polysaccharides are transported to the cell wall in a de-esterified form. At the primary wall, pectins get methyl-esterified at the inner side, thus allowing flexibility of the wall. At the outer side of the wall they become again de-esterified and bind high amounts of calcium which leads to cell wall stiffening. Mucilage vesicles possess the highest calcium-binding capacity of all structures observed in Micrasterias, indicating that the pectic polysaccharides of mucilage are secreted in a de-esterified, compact form. When mucilage is excreted through the cell wall, it loses its ability to bind calcium. The esterification of pectins involved is obviously required for swelling of mucilage by water uptake, which generates the motive force for orientation of this unicellular organism in respect to light. Incubation of Micrasterias in pectin methylesterase (PME), which de-esterifies pectic polymers in higher plants, resulted in growth inhibition, cell shape malformation and primary wall thickening. A PME-like enzyme could be found in Micrasterias by PME activity assays.

Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups.

PubMed

Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A; Bar-On, Benny; Harpaz-Saad, Smadar

2017-04-01

Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns ( Asplenium nidus and Platycerium bifurcatum ) and angiosperms ( Arabidopsis thaliana and Commelina erecta ) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata ( Sorghum bicolor and Triticum aestivum ). Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn could be a consequence of differences in environmental selection along the course of plant evolution. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

The disruptive effect of lysozyme on the bacterial cell wall explored by an in-silico structural outlook.

PubMed

Primo, Emiliano D; Otero, Lisandro H; Ruiz, Francisco; Klinke, Sebastián; Giordano, Walter

2018-01-01

The bacterial cell wall, a structural unit of peptidoglycan polymer comprised of glycan strands consisting of a repeating disaccharide motif [N-acetylglucosamine (NAG) and N-acetylmuramylpentapeptide (NAM pentapeptide)], encases bacteria and provides structural integrity and protection. Lysozymes are enzymes that break down the bacterial cell wall and disrupt the bacterial life cycle by cleaving the linkage between the NAG and NAM carbohydrates. Lab exercises focused on the effects of lysozyme on the bacterial cell wall are frequently incorporated in biochemistry classes designed for undergraduate students in diverse fields as biology, microbiology, chemistry, agronomy, medicine, and veterinary medicine. Such exercises typically do not include structural data. We describe here a sequence of computer tasks designed to illustrate and reinforce both physiological and structural concepts involved in lysozyme effects on the bacterial cell-wall structure. This lab class usually lasts 3.5 hours. First, the instructor presents introductory concepts of the bacterial cell wall and the effect of lysozyme on its structure. Then, students are taught to use computer modeling to visualize the three-dimensional structure of a lysozyme in complex with bacterial cell-wall fragments. Finally, the lysozyme inhibitory effect on a bacterial culture is optionally proposed as a simple microbiological assay. The computer lab exercises described here give students a realistic understanding of the disruptive effect of lysozymes on the bacterial cell wall, a crucial component in bacterial survival. © 2017 by The International Union of Biochemistry and Molecular Biology, 46(1):83-90, 2018. © 2017 The International Union of Biochemistry and Molecular Biology.

Metabolic labelling of the carbohydrate core in bacterial peptidoglycan and its applications

PubMed Central

Liang, Hai; DeMeester, Kristen E.; Hou, Ching-Wen; Parent, Michelle A.; Caplan, Jeffrey L.; Grimes, Catherine L.

2017-01-01

Bacterial cells are surrounded by a polymer known as peptidoglycan (PG), which protects the cell from changes in osmotic pressure and small molecule insults. A component of this material, N-acetyl-muramic acid (NAM), serves as a core structural element for innate immune recognition of PG fragments. We report the synthesis of modifiable NAM carbohydrate derivatives and the installation of these building blocks into the backbone of Gram-positive and Gram-negative bacterial PG utilizing metabolic cell wall recycling and biosynthetic machineries. Whole cells are labelled via click chemistry and visualized using super-resolution microscopy, revealing higher resolution PG structural details and allowing the cell wall biosynthesis, as well as its destruction in immune cells, to be tracked. This study will assist in the future identification of mechanisms that the immune system uses to recognize bacteria, glean information about fundamental cell wall architecture and aid in the design of novel antibiotics. PMID:28425464

The making of the architecture of the plant cell wall: how cells exploit geometry.

PubMed

Emons, A M; Mulder, B M

1998-06-09

Cell wall deposition is a key process in the formation, growth, and differentiation of plant cells. The most important structural components of the wall are long cellulose microfibrils, which are synthesized by synthases embedded in the plasma membrane. A fundamental question is how the microfibrils become oriented during deposition at the plasma membrane. The current textbook explanation for the orientation mechanism is a guidance system mediated by cortical microtubules. However, too many contraindications are known in secondary cell walls for this to be a universal mechanism, particularly in the case of helicoidal arrangements, which occur in many situations. An additional construction mechanism involves liquid crystalline self-assembly [A. C. Neville (1993) Biology of Fibrous Composites: Development Beyond the Cell Membrane (Cambridge Univ. Press, Cambridge, U.K.)], but the required amount of bulk material that is able to equilibrate thermally is not normally present at any stage of the wall deposition process. Therefore, we have asked whether the complex ordered texture of helicoidal cell walls can be formed in the absence of direct cellular guidance mechanisms. We propose that they can be formed by a mechanism that is based on geometrical considerations. It explains the genesis of the complicated helicoidal texture and shows that the cell has intrinsic, versatile tools for creating a variety of textures. A compelling feature of the model is that local rules generate global order, a typical phenomenon of life.

Identification and classification of genes required for tolerance to freeze-thaw stress revealed by genome-wide screening of Saccharomyces cerevisiae deletion strains.

PubMed

Ando, Akira; Nakamura, Toshihide; Murata, Yoshinori; Takagi, Hiroshi; Shima, Jun

2007-03-01

Yeasts used in bread making are exposed to freeze-thaw stress during frozen-dough baking. To clarify the genes required for freeze-thaw tolerance, genome-wide screening was performed using the complete deletion strain collection of diploid Saccharomyces cerevisiae. The screening identified 58 gene deletions that conferred freeze-thaw sensitivity. These genes were then classified based on their cellular function and on the localization of their products. The results showed that the genes required for freeze-thaw tolerance were frequently involved in vacuole functions and cell wall biogenesis. The highest numbers of gene products were components of vacuolar H(+)-ATPase. Next, the cross-sensitivity of the freeze-thaw-sensitive mutants to oxidative stress and to cell wall stress was studied; both of these are environmental stresses closely related to freeze-thaw stress. The results showed that defects in the functions of vacuolar H(+)-ATPase conferred sensitivity to oxidative stress and to cell wall stress. In contrast, defects in gene products involved in cell wall assembly conferred sensitivity to cell wall stress but not to oxidative stress. Our results suggest the presence of at least two different mechanisms of freeze-thaw injury: oxidative stress generated during the freeze-thaw process, and defects in cell wall assembly.

Systems and synthetic biology approaches to alter plant cell walls and reduce biomass recalcitrance

DOE PAGES

Kalluri, Udaya C.; Yin, Hengfu; Yang, Xiaohan; ...

2014-11-03

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host thatmore » carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Finally, synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance.« less

Systems and synthetic biology approaches to alter plant cell walls and reduce biomass recalcitrance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalluri, Udaya C.; Yin, Hengfu; Yang, Xiaohan

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host thatmore » carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Finally, synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance.« less

Elevation of NO production increases Fe immobilization in the Fe-deficiency roots apoplast by decreasing pectin methylation of cell wall

PubMed Central

Ye, Yi Quan; Jin, Chong Wei; Fan, Shi Kai; Mao, Qian Qian; Sun, Cheng Liang; Yu, Yan; Lin, Xian Yong

2015-01-01

Cell wall is the major component of root apoplast which is the main reservoir for iron in roots, while nitric oxide (NO) is involved in regulating the synthesis of cell wall. However, whether such regulation could influence the reutilization of iron stored in root apoplast remains unclear. In this study, we observed that iron deficiency elevated NO level in tomato (Solanum lycopersicum) roots. However, application of S-nitrosoglutathione, a NO donor, significantly enhanced iron retention in root apoplast of iron-deficient plants, accompanied with a decrease of iron level in xylem sap. Consequently, S-nitrosoglutathione treatment increased iron concentration in roots, but decreased it in shoots. The opposite was true for the NO scavenging treatment with 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO). Interestingly, S-nitrosoglutathione treatment increased pectin methylesterase activity and decreased degree of pectin methylation in root cell wall of both iron-deficient and iron-sufficient plants, which led to an increased iron retention in pectin fraction, thus increasing the binding capacity of iron to the extracted cell wall. Altogether, these results suggested that iron-deficiency-induced elevation of NO increases iron immobilization in root apoplast by decreasing pectin methylation in cell wall. PMID:26073914

Functional Dissection of the CroRS Two-Component System Required for Resistance to Cell Wall Stressors in Enterococcus faecalis.

PubMed

Kellogg, Stephanie L; Kristich, Christopher J

2016-04-01

Bacteria use two-component signal transduction systems (TCSs) to sense and respond to environmental changes via a conserved phosphorelay between a sensor histidine kinase and its cognate response regulator. The opportunistic pathogen Enterococcus faecalis utilizes a TCS comprised of the histidine kinase CroS and the response regulator CroR to mediate resistance to cell wall stresses such as cephalosporin antibiotics, but the molecular details by which CroRS promotes cephalosporin resistance have not been elucidated. Here, we analyzed mutants of E. faecalis carrying substitutions in CroR and CroS to demonstrate that phosphorylated CroR drives resistance to cephalosporins, and that CroS exhibits kinase and phosphatase activities to control the level of CroR phosphorylation in vivo. Deletion of croS in various lineages of E. faecalis revealed a CroS-independent mechanism for CroR phosphorylation and led to the identification of a noncognate histidine kinase capable of influencing CroR (encoded by OG1RF_12162; here called cisS). Further analysis of this TCS network revealed that both systems respond to cell wall stress. TCSs allow bacteria to sense and respond to many different environmental conditions. The opportunistic pathogen Enterococcus faecalis utilizes the CroRS TCS to mediate resistance to cell wall stresses, including clinically relevant antibiotics such as cephalosporins and glycopeptides. In this study, we use genetic and biochemical means to investigate the relationship between CroRS signaling and cephalosporin resistance in E. faecalis cells. Through this, we uncovered a signaling network formed between the CroRS TCS and a previously uncharacterized TCS that also responds to cell wall stress. This study provides mechanistic insights into CroRS signaling and cephalosporin resistance in E. faecalis. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Helicoidal pattern in secondary cell walls and possible role of xylans in their construction.

PubMed

Reis, Danièle; Vian, Brigitte

2004-01-01

The helicoidal organization of secondary cell walls is overviewed from several examples. Both the plywood texture and the occurrence of characteristic defects strongly suggest that the wall ordering is relevant of a cholesteric liquid-crystal assembly that is rapidly and strongly consolidated by lignification. A preferential localization of glucuronoxylans, major matrix components, and in vitro re-association experiments emphasize their preeminent role: (1) during the construction of the composite as directing the cellulose microfibrils in a helicoidal array; (2) during the lignification of the composite as a host structure for lignin precursors.

Deletion of Aspergillus nidulans GDP-mannose transporters affects hyphal morphometry, cell wall architecture, spore surface character, cell adhesion, and biofilm formation.

PubMed

Kadry, Ashraf A; El-Ganiny, Amira M; Mosbah, Rasha A; Kaminskyj, Susan G W

2018-07-01

Systemic human fungal infections are increasingly common. Aspergillus species cause most of the airborne fungal infections. Life-threatening invasive aspergillosis was formerly found only in immune-suppressed patients, but recently some strains of A. fumigatus have become primary pathogens. Many fungal cell wall components are absent from mammalian systems, so they are potential drug targets. Cell-wall-targeting drugs such as echinocandins are used clinically, although echinocandin-resistant strains were discovered shortly after their introduction. Currently there are no fully effective anti-fungal drugs. Fungal cell wall glycoconjugates modulate human immune responses, as well as fungal cell adhesion, biofilm formation, and drug resistance. Guanosine diphosphate (GDP) mannose transporters (GMTs) transfer GDP-mannose from the cytosol to the Golgi lumen prior to mannosylation. Aspergillus nidulans GMTs are encoded by gmtA and gmtB. Here we elucidate the roles of A. nidulans GMTs. Strains engineered to lack either or both GMTs were assessed for hyphal and colonial morphology, cell wall ultrastructure, antifungal susceptibility, spore hydrophobicity, adherence and biofilm formation. The gmt-deleted strains had smaller colonies with reduced sporulation and with thicker hyphal walls. The gmtA deficient spores had reduced hydrophobicity and were less adherent and less able to form biofilms in vitro. Thus, gmtA not only participates in maintaining the cell wall integrity but also plays an important role in biofilm establishment and adherence of A. nidulans. These findings suggested that GMTs have roles in A. nidulans growth and cell-cell interaction and could be a potential target for new antifungals that target virulence determinants.

Recognition of Histo-Blood Group Antigen-Like Carbohydrates in Lettuce by Human GII.4 Norovirus

PubMed Central

Gao, Xiang; Esseili, Malak A.; Lu, Zhongyan; Saif, Linda J.

2016-01-01

ABSTRACT Human norovirus (HuNoV) genogroup II genotype 4 (GII.4) strains account for about 80% of the gastroenteritis outbreaks in the United States. Contaminated food is a major transmission vehicle for this virus. In humans, pigs, and oysters, histo-blood group antigens (HBGAs) act as attachment factors for HuNoVs. In lettuce, although the virus-like particles (VLPs) of a GII.4 HuNoV were found to bind to cell wall carbohydrates, the exact binding site has not been investigated. Here, we show the presence of HBGA-like carbohydrates in the cell wall of lettuce. The digestion of lettuce leaves with cell wall-degrading enzymes exposed more binding sites and significantly increased the level of binding of GII.4 HuNoV VLPs. Competition assays showed that both the HBGA monoclonal antibody, recognizing the H type, and plant lectins, recognizing α-l-fucose in the H type, effectively inhibited VLP binding to lettuce tissues. Lettuce cell wall components were isolated and their NoV VLP binding characteristics were tested by enzyme-linked immunosorbent assays. The binding was inhibited by pretreatment of the lettuce cell wall materials with α-1,2-fucosidase. Collectively, our results indicate that H-type HBGA-like carbohydrates exist in lettuce tissues and that GII.4 HuNoV VLPs can bind the exposed fucose moiety, possibly in the hemicellulose component of the cell wall. IMPORTANCE Salad crops and fruits are increasingly recognized as vehicles for human norovirus (HuNoV) transmission. A recent study showed that HuNoVs specifically bind to the carbohydrates of the lettuce cell wall. Histo-blood group antigens (HBGAs) are carbohydrates and are known as the attachment factors for HuNoV infection in humans. In this study, we show the presence of HBGA-like carbohydrates in lettuce, to which HuNoVs specifically bind. These results suggest that specifically bound HuNoVs cannot be removed by simple washing, which may allow viral transmission to consumers. Our findings provide new information needed for developing potential inhibitors to block binding and prevent contamination. PMID:26969699

Recognition of Histo-Blood Group Antigen-Like Carbohydrates in Lettuce by Human GII.4 Norovirus.

PubMed

Gao, Xiang; Esseili, Malak A; Lu, Zhongyan; Saif, Linda J; Wang, Qiuhong

2016-05-15

Human norovirus (HuNoV) genogroup II genotype 4 (GII.4) strains account for about 80% of the gastroenteritis outbreaks in the United States. Contaminated food is a major transmission vehicle for this virus. In humans, pigs, and oysters, histo-blood group antigens (HBGAs) act as attachment factors for HuNoVs. In lettuce, although the virus-like particles (VLPs) of a GII.4 HuNoV were found to bind to cell wall carbohydrates, the exact binding site has not been investigated. Here, we show the presence of HBGA-like carbohydrates in the cell wall of lettuce. The digestion of lettuce leaves with cell wall-degrading enzymes exposed more binding sites and significantly increased the level of binding of GII.4 HuNoV VLPs. Competition assays showed that both the HBGA monoclonal antibody, recognizing the H type, and plant lectins, recognizing α-l-fucose in the H type, effectively inhibited VLP binding to lettuce tissues. Lettuce cell wall components were isolated and their NoV VLP binding characteristics were tested by enzyme-linked immunosorbent assays. The binding was inhibited by pretreatment of the lettuce cell wall materials with α-1,2-fucosidase. Collectively, our results indicate that H-type HBGA-like carbohydrates exist in lettuce tissues and that GII.4 HuNoV VLPs can bind the exposed fucose moiety, possibly in the hemicellulose component of the cell wall. Salad crops and fruits are increasingly recognized as vehicles for human norovirus (HuNoV) transmission. A recent study showed that HuNoVs specifically bind to the carbohydrates of the lettuce cell wall. Histo-blood group antigens (HBGAs) are carbohydrates and are known as the attachment factors for HuNoV infection in humans. In this study, we show the presence of HBGA-like carbohydrates in lettuce, to which HuNoVs specifically bind. These results suggest that specifically bound HuNoVs cannot be removed by simple washing, which may allow viral transmission to consumers. Our findings provide new information needed for developing potential inhibitors to block binding and prevent contamination. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Carbohydrate Microarray Technology Applied to High-Throughput Mapping of Plant Cell Wall Glycans Using Comprehensive Microarray Polymer Profiling (CoMPP).

PubMed

Kračun, Stjepan Krešimir; Fangel, Jonatan Ulrik; Rydahl, Maja Gro; Pedersen, Henriette Lodberg; Vidal-Melgosa, Silvia; Willats, William George Tycho

2017-01-01

Cell walls are an important feature of plant cells and a major component of the plant glycome. They have both structural and physiological functions and are critical for plant growth and development. The diversity and complexity of these structures demand advanced high-throughput techniques to answer questions about their structure, functions and roles in both fundamental and applied scientific fields. Microarray technology provides both the high-throughput and the feasibility aspects required to meet that demand. In this chapter, some of the most recent microarray-based techniques relating to plant cell walls are described together with an overview of related contemporary techniques applied to carbohydrate microarrays and their general potential in glycoscience. A detailed experimental procedure for high-throughput mapping of plant cell wall glycans using the comprehensive microarray polymer profiling (CoMPP) technique is included in the chapter and provides a good example of both the robust and high-throughput nature of microarrays as well as their applicability to plant glycomics.

Binding of /sup 18/F by cell membranes and cell walls of Streptococcus mutans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yotis, W.W.; Zeb, M.; McNulty, J.

1983-07-01

The binding of /sup 18/F to isolated cell membranes and cell walls of Streptococcus mutans GS-5 or other bacteria was assayed. The attachment of /sup 18/F to these cell envelopes proceeded slowly and reached equilibrium within 60 min. /sup 18/F binding was stimulated by Ca/sup 2 +/ (1 mM). The binding of /sup 18/F to cellular components was dependent upon the pH, as well as the amount of /sup 18/F and dose of the binder employed. The binding of /sup 18/F by cell walls prepared from fluoride-sensitive and fluoride-resistant cells of S. salivarius and S. mutans did not differ significantly.more » The pretreatment of cell walls or cell membranes for 60 min at 30 degrees C with 1 mg of RNase, DNase, or trypsin per ml did not influence the binding of /sup 18/F by the walls and membranes of S. mutans GS-5. However, prior exposure of cell membranes to sodium dodecyl sulfate caused a significant reduction in the number of /sup 18/F atoms bound by the membranes. In saturated assay systems, cell membranes of S. mutans GS-5 bound 10(15) to 10(16) atoms of /sup 18/F per mg (dry weight), whereas cell walls from S. mutans GS-5, FA-1, and HS-6 or Actinomyces viscosus T14V and T14AV bound 10(12) to 10(13) atoms of /sup 18/F per mg (dry weight). /sup 18/F in this quantity (10(12) to 10(13) atoms) cannot be detected with the fluoride electrode. The data provide, for the first time, a demonstration of /sup 18/F binding by cell membranes and walls of oral flora.« less

Elevated CO2 concentration impacts cell wall polysaccharide composition of green microalgae of the genus Chlorella.

PubMed

Cheng, Y-S; Labavitch, J M; VanderGheynst, J S

2015-01-01

The effect of CO2 concentration on the relative content of starch, lipid and cell wall carbohydrates in microalgal biomass was investigated for the four following Chlorella strains: C. vulgaris (UTEX 259), C. sorokiniana (UTEX 2805), C. minutissima (UTEX 2341) and C. variabilis (NC64A). Each strain had a different response to CO2 concentration. The starch content was higher in UTEX259 and NC64A cultured with 2% CO2 in the air supply than in cells cultured with ca. 0·04% CO2 (ambient air), while starch content was not affected for UTEX 2805 and UTEX 2341. The lipid content was higher in Chlorella minutissima UTEX 2341 cultured in 2% CO2 than in cells cultured in ambient air, but was unchanged for the other three strains. All four Chlorella strains tended to have a higher percentage of uronic acids and lower percentage of neutral sugars in their cell wall polysaccharide complement when grown with 2% CO2 supply. Although the percentage of neutral sugars in the cell walls varied with CO2 concentration, the relative proportions of different neutral sugar constituents remained constant for both CO2 conditions. The results demonstrate the importance of considering the effects of CO2 on the cell wall carbohydrate composition of microalgae. Microalgae have the potential to produce products that will reduce society's reliance on fossil fuels and address challenges related to food and feed production. An overlooked yet industrially relevant component of microalgae are their cell walls. Cell wall composition affects cell flocculation and the recovery of intracellular products. In this study, we show that increasing CO2 level results in greater cell wall polysaccharide and uronic acid content in the cell walls of three strains of microalgae. The results have implications on the management of systems for the capture of CO2 and production of fuels, chemicals and food from microalgae. © 2014 The Society for Applied Microbiology.

Human beta-defensin 3 inhibits cell wall biosynthesis in Staphylococci.

PubMed

Sass, Vera; Schneider, Tanja; Wilmes, Miriam; Körner, Christian; Tossi, Alessandro; Novikova, Natalia; Shamova, Olga; Sahl, Hans-Georg

2010-06-01

Human beta-defensin 3 (hBD3) is a highly charged (+11) cationic host defense peptide, produced by epithelial cells and neutrophils. hBD3 retains antimicrobial activity against a broad range of pathogens, including multiresistant Staphylococcus aureus, even under high-salt conditions. Whereas antimicrobial host defense peptides are assumed to act by permeabilizing cell membranes, the transcriptional response pattern of hBD3-treated staphylococcal cells resembled that of vancomycin-treated cells (V. Sass, U. Pag, A. Tossi, G. Bierbaum, and H. G. Sahl, Int. J. Med. Microbiol. 298:619-633, 2008) and suggested that inhibition of cell wall biosynthesis is a major component of the killing process. hBD3-treated cells, inspected by transmission electron microscopy, showed localized protrusions of cytoplasmic contents, and analysis of the intracellular pool of nucleotide-activated cell wall precursors demonstrated accumulation of the final soluble precursor, UDP-MurNAc-pentapeptide. Accumulation is typically induced by antibiotics that inhibit membrane-bound steps of cell wall biosynthesis and also demonstrates that hBD3 does not impair the biosynthetic capacity of cells and does not cause gross leakage of small cytoplasmic compounds. In in vitro assays of individual membrane-associated cell wall biosynthesis reactions (MraY, MurG, FemX, and penicillin-binding protein 2 [PBP2]), hBD3 inhibited those enzymes which use the bactoprenol-bound cell wall building block lipid II as a substrate; quantitative analysis suggested that hBD3 may stoichiometrically bind to lipid II. We report that binding of hBD3 to defined, lipid II-rich sites of cell wall biosynthesis may lead to perturbation of the biosynthesis machinery, resulting in localized lesions in the cell wall as demonstrated by electron microscopy. The lesions may then allow for osmotic rupture of cells when defensins are tested under low-salt conditions.

Human β-Defensin 3 Inhibits Cell Wall Biosynthesis in Staphylococci▿

PubMed Central

Sass, Vera; Schneider, Tanja; Wilmes, Miriam; Körner, Christian; Tossi, Alessandro; Novikova, Natalia; Shamova, Olga; Sahl, Hans-Georg

2010-01-01

Human β-defensin 3 (hBD3) is a highly charged (+11) cationic host defense peptide, produced by epithelial cells and neutrophils. hBD3 retains antimicrobial activity against a broad range of pathogens, including multiresistant Staphylococcus aureus, even under high-salt conditions. Whereas antimicrobial host defense peptides are assumed to act by permeabilizing cell membranes, the transcriptional response pattern of hBD3-treated staphylococcal cells resembled that of vancomycin-treated cells (V. Sass, U. Pag, A. Tossi, G. Bierbaum, and H. G. Sahl, Int. J. Med. Microbiol. 298:619-633, 2008) and suggested that inhibition of cell wall biosynthesis is a major component of the killing process. hBD3-treated cells, inspected by transmission electron microscopy, showed localized protrusions of cytoplasmic contents, and analysis of the intracellular pool of nucleotide-activated cell wall precursors demonstrated accumulation of the final soluble precursor, UDP-MurNAc-pentapeptide. Accumulation is typically induced by antibiotics that inhibit membrane-bound steps of cell wall biosynthesis and also demonstrates that hBD3 does not impair the biosynthetic capacity of cells and does not cause gross leakage of small cytoplasmic compounds. In in vitro assays of individual membrane-associated cell wall biosynthesis reactions (MraY, MurG, FemX, and penicillin-binding protein 2 [PBP2]), hBD3 inhibited those enzymes which use the bactoprenol-bound cell wall building block lipid II as a substrate; quantitative analysis suggested that hBD3 may stoichiometrically bind to lipid II. We report that binding of hBD3 to defined, lipid II-rich sites of cell wall biosynthesis may lead to perturbation of the biosynthesis machinery, resulting in localized lesions in the cell wall as demonstrated by electron microscopy. The lesions may then allow for osmotic rupture of cells when defensins are tested under low-salt conditions. PMID:20385753

Homogalacturonan methyl-esterification and plant development.

PubMed

Wolf, Sebastian; Mouille, Grégory; Pelloux, Jérome

2009-09-01

The ability of a plant cell to expand is largely defined by the physical constraints imposed by its cell wall. Accordingly, cell wall properties have to be regulated during development. The pectic polysaccharide homogalacturonan is a major component of the plant primary walls. Biosynthesis and in muro modification of homogalacturonan have recently emerged as key determinants of plant development, controlling cell adhesion, organ development, and phyllotactic patterning. This review will focus on recent findings regarding impact of homogalacturonan content and methyl-esterification status of this polymer on plant life. De-methyl-esterification of homogalacturonan occurs through the action of the ubiquitous enzyme 'pectin methyl-esterase'. We here describe various strategies developed by the plant to finely tune the methyl-esterification status of homogalacturonan along key events of the plant lifecycle.

Raman imaging to investigate ultrastructure and composition of plant cell walls: distribution of lignin and cellulose in black spruce wood (Picea mariana).

PubMed

Agarwal, Umesh P

2006-10-01

A detailed understanding of the structural organization of the cell wall of vascular plants is important from both the perspectives of plant biology and chemistry and of commercial utilization. A state-of-the-art 633-nm laser-based confocal Raman microscope was used to determine the distribution of cell wall components in the cross section of black spruce wood in situ. Chemical information from morphologically distinct cell wall regions was obtained and Raman images of lignin and cellulose spatial distribution were generated. While cell corner (CC) lignin concentration was the highest on average, lignin concentration in compound middle lamella (CmL) was not significantly different from that in secondary wall (S2 and S2-S3). Images generated using the 1,650 cm(-1) band showed that coniferaldehyde and coniferyl alcohol distribution followed that of lignin and no particular cell wall layer/region was therefore enriched in the ethylenic residue. In contrast, cellulose distribution showed the opposite pattern-low concentration in CC and CmL and high in S2 regions. Nevertheless, cellulose concentration varied significantly in some areas, and concentrations of both lignin and cellulose were high in other areas. Though intensity maps of lignin and cellulose distributions are currently interpreted solely in terms of concentration differences, the effect of orientation needs to be carefully considered to reveal the organization of the wood cell wall.

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

PubMed

Camacho, Emma; Chrissian, Christine; Cordero, Radames J B; Liporagi-Lopes, Livia; Stark, Ruth E; Casadevall, Arturo

2017-11-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15 N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In summary, GlcNAc supplementation had pleiotropic effects on cell-wall and melanin architectures, and thus established its capacity to perturb these structures, a property that could prove useful for metabolic tracking studies.

N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture

PubMed Central

Camacho, Emma; Chrissian, Christine; Cordero, Radames J. B.; Liporagi-Lopes, Livia; Stark, Ruth E.; Casadevall, Arturo

2017-01-01

Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother–daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In summary, GlcNAc supplementation had pleiotropic effects on cell-wall and melanin architectures, and thus established its capacity to perturb these structures, a property that could prove useful for metabolic tracking studies. PMID:29043954

Investigation of Plant Cell Wall Properties: A Study of Contributions from the Nanoscale to the Macroscale Impacting Cell Wall Recalcitrance

NASA Astrophysics Data System (ADS)

Crowe, Jacob Dillon

Biochemical conversion of lignocellulosic biomass to fuel ethanol is one of a few challenging, yet opportune technologies that can reduce the consumption of petroleum-derived transportation fuels, while providing parallel reductions in greenhouse gas emissions. Biomass recalcitrance, or resistance to deconstruction, is a major technical challenge that limits effective conversion of biomass to fermentable sugars, often requiring a costly thermochemical pretreatment step to improve biomass deconstruction. Biomass recalcitrance is imparted largely by the secondary cell wall, a complex polymeric matrix of cell wall polysaccharides and aromatic heteropolymers, that provides structural stability to cells and enables plant upright growth. Polymers within the cell wall can vary both compositionally and structurally depending upon plant species and anatomical fraction, and have varied responses to thermochemical pretreatments. Cell wall properties impacting recalcitrance are still not well understood, and as a result, the goal of this dissertation is to investigate structural features of the cell wall contributing to recalcitrance (1) in diverse anatomical fractions of a single species, (2) in response to diverse pretreatments, and (3) resulting from genetic modification. In the first study, feedstock cell wall heterogeneity was investigated in anatomical (stem, leaf sheaths, and leaf blades) and internode fractions of switchgrass at varying tissue maturities. Lignin content was observed as the key contributor to recalcitrance in maturing stem tissues only, with non-cellulosic substituted glucuronoarabinoxylans and pectic polysaccharides contributing to cell wall recalcitrance in leaf sheath and leaf blades. Hydroxycinnamate (i.e., saponifiable p-coumarate and ferulate) content along with xylan and pectin extractability decreased with tissue maturity, suggesting lignification is only one component imparting maturity specific cell wall recalcitrance. In the second study, alkaline hydrogen peroxide and liquid hot water pretreatments were shown to alter structural properties impacting nanoscale porosity in corn stover. Delignification by alkaline hydrogen peroxide pretreatment decreased cell wall rigidity, with subsequent cell wall swelling resulting in increased nanoscale porosity and improved enzymatic hydrolysis compared to limited swelling and increased accessible surface areas observed in liquid hot water pretreated biomass. The volume accessible to a 90 A dextran probe within the cell wall was found to be positively correlated to both enzyme binding and glucose hydrolysis yields, indicating cell wall porosity is a key contributor to effective hydrolysis yields. In the third study, the effect of altered xylan content and structure was investigated in irregular xylem (irx) Arabidopsis thaliana mutants to understand the role xylan plays in secondary cell wall development and organization. Higher xylan extractability and lower cellulose crystallinity observed in irx9 and irx15 irx15-L mutants compared to wild type indicated altered xylan integration into the secondary cell wall. Nanoscale cell wall organization observed using multiple microscopy techniques was impacted to some extent in all irx mutants, with disorganized cellulose microfibril layers in sclerenchyma secondary cell walls likely resulting from irregular xylan structure and content. Irregular secondary cell wall microfibril layers showed heterogeneous nanomechanical properties compared to wild type, which translated to mechanical deficiencies observed in stem tensile tests. These results suggest nanoscale defects in cell wall strength can correspond to macroscale phenotypes.

Cytochemical Labeling for Fungal and Host Components in Plant Tissues Inoculated with Fungal Wilt Pathogens

NASA Astrophysics Data System (ADS)

Ouellette, G. B.; Baayen, R. P.; Chamberland, H.; Simard, M.; Rioux, D.; Charest, P. M.

2004-08-01

Antibodies to detect pectin in present investigations attached to distinct fibrils in vessel lumina. In carnation infected with an isolate of Fusarium oxysporum f.sp., labeling of pathogen cells also occurred; in a resistant cultivar (cv.), it was coincident with proximate pectin fibrils and linked to altered fungal walls, which was the opposite in the susceptible cv., indicating that hindrance of pathogen ability to degrade pectin may be related to resistance. Labeling of the fungus in culture was nil, except in media containing pectin, showing that pectin is not native to the pathogen. Labeling of fungal walls for cellulose in elm (inoculated with Ophiostoma novo-ulmi) and carnation also occurred, linked to adsorbed host wall components. The chitin probe often attached to dispersed matter, in vessel lumina, traceable to irregularly labeled fungal cells and host wall degradation products. With an anti-horseradish peroxidase probe, host and fungal walls were equally labeled, and with a glucosidase, differences of labeling between these walls were observed, depending on pH of the test solution. Fungal extracellular matter and filamentous structures, present in fungal walls, predominantly in another elm isolate (Phaeotheca dimorphospora), did not label with any of the probes used. However, in cultures of this fungus, extracellular material labeled, even at a distance from the colony margin, with an anti-fimbriae probe.

Changes in cell wall architecture of wheat coleoptiles grown under continuous hypergravity conditions

NASA Astrophysics Data System (ADS)

Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

Modifications of cell wall structure of wheat coleoptiles in response to continuous hypergravity (300 g) treatment were investigated. Length of coleoptiles exposed to hypergravity for 2-4 days from germination stage was 60-70% of that of 1 g control. The net amounts of cell wall polysaccharides, such as hemicellulose and cellulose, of hypergravity-treated coleoptiles increased as much as those of 1 g control coleoptiles during the incubation period. As a result, the levels of cell wall polysaccharides per unit length of coleoptile, which mean the thickness of cell walls, largely increased under hypergravity conditions. Particularly, the amounts of hemicellulosic polymers with middle molecular mass (0.2-1 MDa) largely increased from day 2 to 3 under hypergravity conditions. The major sugar components of the hemicellulose fraction are arabinose, xylose and glucose. The ratios of arabinose and xylose to glucose were higher in hypergravity-treated coleoptiles than in control coleoptiles. The fractionation of hemicellulosic polymers into the neutral and acidic polymers by the anion-exchange column showed that the levels of acidic polymers (mainly composed of arabinoxylans) in cell walls of hypergravity-treated coleoptiles were higher than those of control coleoptiles. In addition to wall polysaccharides, the amounts of cell wall-bound phenolics, such as ferulic acid and diferulic acid, substantially increased during the incubation period both in 1 g control and hypergravity-treated coleoptiles. Especially, the levels of diferulic acid which cross-links hemicellulosic polymers were higher in hypergravity-treated coleoptiles than in control coleoptiles during the incubation period. These results suggest that hypergravity stimuli from the germination stage bias the type of synthesized hemicellulosic polysaccharides, although they do not restrict the net synthesis of cell wall constituents in wheat coleoptiles. The stimulation of the synthesis of arabinoxylans and of the formation of DFA, and also the resultant cell wall thickening may contribute to plant resistance to gravity stimuli.

Photoinhibition of stem elongation by blue and red light: effects on hydraulic and cell wall properties

NASA Technical Reports Server (NTRS)

Kigel, J.; Cosgrove, D. J.

1991-01-01

The underlying mechanism of photoinhibition of stem elongation by blue (BL) and red light (RL) was studied in etiolated seedlings of pea (Pisum sativum L. cv Alaska). Brief BL irradiations resulted in fast transient inhibition of elongation, while a delayed (lag approximately 60 minutes) but prolonged inhibition was observed after brief RL. Possible changes in the hydraulic and wall properties of the growing cells during photoinhibition were examined. Cell sap osmotic pressure was unaffected by BL and RL, but both irradiations increased turgor pressure by approximately 0.05 megapascal (pressure-probe technique). Cell wall yielding was analyzed by in vivo stress relaxation (pressure-block technique). BL and RL reduced the initial rate of relaxation by 38 and 54%, while the final amount of relaxation was decreased by 48 and 10%, respectively. These results indicate that RL inhibits elongation mainly by lowering the wall yield coefficient, while most of the inhibitory effect of BL was due to an increase of the yield threshold. Mechanical extensibility of cell walls (Instron technique) was decreased by BL and RL, mainly due to a reduction in the plastic component of extensibility. Thus, photoinhibitions of elongation by both BL and RL are achieved through changes in cell wall properties, and are not due to effects on the hydraulic properties of the cell.

Enzyme-Less Growth in Chara and Terrestrial Plants

DOE PAGES

Boyer, John S.

2016-06-21

Enzyme-less chemistry appears to control the growth rate of the green alga Chara corallina. The chemistry occurs in the wall where a calcium pectate cycle determines both the rate of wall enlargement and the rate of pectate deposition into the wall. The process is the first to indicate that a wall polymer can control how a plant cell enlarges after exocytosis releases the polymer to the wall. This raises the question of whether other species use a similar mechanism. Chara is one of the closest relatives of the progenitors of terrestrial plants and during the course of evolution, new wallmore » features evolved while pectate remained one of the most conserved components. In addition, charophytes contain auxin which affects Chara in ways resembling its action in terrestrial plants. Furthermore, this review considers whether more recently acquired wall features require different mechanisms to explain cell expansion.« less

Enzyme-Less Growth in Chara and Terrestrial Plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyer, John S.

Enzyme-less chemistry appears to control the growth rate of the green alga Chara corallina. The chemistry occurs in the wall where a calcium pectate cycle determines both the rate of wall enlargement and the rate of pectate deposition into the wall. The process is the first to indicate that a wall polymer can control how a plant cell enlarges after exocytosis releases the polymer to the wall. This raises the question of whether other species use a similar mechanism. Chara is one of the closest relatives of the progenitors of terrestrial plants and during the course of evolution, new wallmore » features evolved while pectate remained one of the most conserved components. In addition, charophytes contain auxin which affects Chara in ways resembling its action in terrestrial plants. Furthermore, this review considers whether more recently acquired wall features require different mechanisms to explain cell expansion.« less

Monolithic solid electrolyte oxygen pump

DOEpatents

Fee, Darrell C.; Poeppel, Roger B.; Easler, Timothy E.; Dees, Dennis W.

1989-01-01

A multi-layer oxygen pump having a one-piece, monolithic ceramic structure affords high oxygen production per unit weight and volume and is thus particularly adapted for use as a portable oxygen supply. The oxygen pump is comprised of a large number of small cells on the order of 1-2 millimeters in diameter which form the walls of the pump and which are comprised of thin, i.e., 25-50 micrometers, ceramic layers of cell components. The cell components include an air electrode, an oxygen electrode, an electrolyte and interconnection materials. The cell walls form the passages for input air and for exhausting the oxygen which is transferred from a relatively dilute gaseous mixture to a higher concentration by applying a DC voltage across the electrodes so as to ionize the oxygen at the air electrode, whereupon the ionized oxygen travels through the electrolyte and is converted to oxygen gas at the oxygen electrode.

Pectin in foods

USDA-ARS?s Scientific Manuscript database

Pectin, a complex polysaccharide, is a major component of non-lignified cell walls of dicotyledonous and some monocotyledonous plants. Its food-related technological functions are numerous and mirror many of its biological functions. As a naturally occurring component of raw or processed foods and a...

Short communication: Antiproliferative effect of wild Lactobacillus strains isolated from fermented foods on HT-29 cells.

PubMed

Tuo, Y F; Zhang, L W; Yi, H X; Zhang, Y C; Zhang, W Q; Han, X; Du, M; Jiao, Y H; Wang, S M

2010-06-01

In vitro studies, animal models, epidemiology, and human intervention studies provide evidence that some lactic acid bacteria can reduce the risk of certain cancers. In this study, heat-killed bacterial cells, genomic DNA, and cell wall of 7 wild Lactobacillus strains isolated from traditional fermented foods in western China were tested in vitro for cytotoxicity on colonic cancer cell line HT-29 by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The heat-killed bacterial cells, genomic DNA, and cell wall of the 7 strains exhibited direct antiproliferative activities against HT-29 cells. Among the strains, the cellular components of Lactobacillus coryniformis ssp. torquens T3L exerted marked antiproliferative activities against HT-29 cells. The maximum inhibition rates of HT-29 cells by the heat-killed bacterial cells (1x10(7) cfu/mL), cell wall (20 microg of protein/mL) and genomic DNA (100 microg/mL) of L. coryniformis ssp. torquens T3L were 30, 44.9, and 35.9%, respectively. The results indicate that the heat-killed bacterial cells, cell wall, and genomic DNA of the 7 wild Lactobacillus strains could inhibit the growth of HT-29 cells. 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Storage related changes of cell wall based dietary fiber components of broccoli (Brassica oleracea var. italica) stems.

PubMed

Schäfer, Judith; Stanojlovic, Luisa; Trierweiler, Bernhard; Bunzel, Mirko

2017-03-01

Storage related changes in the cell wall composition potentially affect the texture of plant-based foods and the physiological effects of cell wall based dietary fiber components. Therefore, a detailed characterization of cell wall polysaccharides and lignins from broccoli stems was performed. Freshly harvested broccoli and broccoli stored at 20°C and 1°C for different periods of time were analyzed. Effects on dietary fiber contents, polysaccharide composition, and on lignin contents/composition were much more pronounced during storage at 20°C than at 1°C. During storage, insoluble dietary fiber contents of broccoli stems increased up to 13%. Storage related polysaccharide modifications include an increase of the portions of cellulose, xylans, and homogalacturonans and a decrease of the neutral pectic side-chains arabinans and galactans. Broccoli stem lignins are generally rich in guaiacyl units. Lignins from freshly harvested broccoli stems contain slightly larger amounts of p-hydroxyphenyl units than syringyl units. Syringyl units are predominantly incorporated into the lignin polymers during storage, resulting in increased acetyl bromide soluble lignin contents. NMR-based analysis of the interunit linkage types of broccoli stem lignins revealed comparably large portions of resinol structures for a guaiacyl rich lignin. Incorporation of syringyl units into the polymers over storage predominantly occurs through β-O-4-linkages. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insights into plant cell wall structure, architecture, and integrity using glycome profiling of native and AFEXTM-pre-treated biomass

PubMed Central

Pattathil, Sivakumar; Hahn, Michael G.; Dale, Bruce E.; Chundawat, Shishir P. S.

2015-01-01

Cell walls, which constitute the bulk of plant biomass, vary considerably in their structure, composition, and architecture. Studies on plant cell walls can be conducted on both native and pre-treated plant biomass samples, allowing an enhanced understanding of these structural and compositional variations. Here glycome profiling was employed to determine the relative abundance of matrix polysaccharides in several phylogenetically distinct native and pre-treated plant biomasses. Eight distinct biomass types belonging to four different subgroups (i.e. monocot grasses, woody dicots, herbaceous dicots, and softwoods) were subjected to various regimes of AFEX™ (ammonia fiber expansion) pre-treatment [AFEX is a trademark of MBI, Lansing (http://www.mbi.org]. This approach allowed detailed analysis of close to 200 cell wall glycan epitopes and their relative extractability using a high-throughput platform. In general, irrespective of the phylogenetic origin, AFEX™ pre-treatment appeared to cause loosening and improved accessibility of various xylan epitope subclasses in most plant biomass materials studied. For most biomass types analysed, such loosening was also evident for other major non-cellulosic components including subclasses of pectin and xyloglucan epitopes. The studies also demonstrate that AFEX™ pre-treatment significantly reduced cell wall recalcitrance among diverse phylogenies (except softwoods) by inducing structural modifications to polysaccharides that were not detectable by conventional gross composition analyses. It was found that monitoring changes in cell wall glycan compositions and their relative extractability for untreated and pre-treated plant biomass can provide an improved understanding of variations in structure and composition of plant cell walls and delineate the role(s) of matrix polysaccharides in cell wall recalcitrance. PMID:25911738

Insights into plant cell wall structure, architecture, and integrity using glycome profiling of native and AFEX TM -pre-treated biomass

DOE PAGES

Pattathil, Sivakumar; Hahn, Michael G.; Dale, Bruce E.; ...

2015-04-23

We report that cell walls, which constitute the bulk of plant biomass, vary considerably in their structure, composition, and architecture. Studies on plant cell walls can be conducted on both native and pre-treated plant biomass samples, allowing an enhanced understanding of these structural and compositional variations. Here glycome profiling was employed to determine the relative abundance of matrix polysaccharides in several phylogenetically distinct native and pre-treated plant biomasses. Eight distinct biomass types belonging to four different subgroups (i.e. monocot grasses, woody dicots, herbaceous dicots, and softwoods) were subjected to various regimes of AFEX™ (ammonia fiber expansion) pre-treatment [AFEX is amore » trademark of MBI, Lansing (http://www.mbi.org]. This approach allowed detailed analysis of close to 200 cell wall glycan epitopes and their relative extractability using a high-throughput platform. In general, irrespective of the phylogenetic origin, AFEX™ pre-treatment appeared to cause loosening and improved accessibility of various xylan epitope subclasses in most plant biomass materials studied. For most biomass types analysed, such loosening was also evident for other major non-cellulosic components including subclasses of pectin and xyloglucan epitopes. The studies also demonstrate that AFEX™ pre-treatment significantly reduced cell wall recalcitrance among diverse phylogenies (except softwoods) by inducing structural modifications to polysaccharides that were not detectable by conventional gross composition analyses. Lastly, we found that monitoring changes in cell wall glycan compositions and their relative extractability for untreated and pre-treated plant biomass can provide an improved understanding of variations in structure and composition of plant cell walls and delineate the role(s) of matrix polysaccharides in cell wall recalcitrance.« less

The genetic interaction network of CCW12, a Saccharomyces cerevisiae gene required for cell wall integrity during budding and formation of mating projections

PubMed Central

2011-01-01

Background Mannoproteins construct the outer cover of the fungal cell wall. The covalently linked cell wall protein Ccw12p is an abundant mannoprotein. It is considered as crucial structural cell wall component since in baker's yeast the lack of CCW12 results in severe cell wall damage and reduced mating efficiency. Results In order to explore the function of CCW12, we performed a Synthetic Genetic Analysis (SGA) and identified genes that are essential in the absence of CCW12. The resulting interaction network identified 21 genes involved in cell wall integrity, chitin synthesis, cell polarity, vesicular transport and endocytosis. Among those are PFD1, WHI3, SRN2, PAC10, FEN1 and YDR417C, which have not been related to cell wall integrity before. We correlated our results with genetic interaction networks of genes involved in glucan and chitin synthesis. A core of genes essential to maintain cell integrity in response to cell wall stress was identified. In addition, we performed a large-scale transcriptional analysis and compared the transcriptional changes observed in mutant ccw12Δ with transcriptomes from studies investigating responses to constitutive or acute cell wall damage. We identified a set of genes that are highly induced in the majority of the mutants/conditions and are directly related to the cell wall integrity pathway and cell wall compensatory responses. Among those are BCK1, CHS3, EDE1, PFD1, SLT2 and SLA1 that were also identified in the SGA. In contrast, a specific feature of mutant ccw12Δ is the transcriptional repression of genes involved in mating. Physiological experiments substantiate this finding. Further, we demonstrate that Ccw12p is present at the cell periphery and highly concentrated at the presumptive budding site, around the bud, at the septum and at the tip of the mating projection. Conclusions The combination of high throughput screenings, phenotypic analyses and localization studies provides new insight into the function of Ccw12p. A compensatory response, culminating in cell wall remodelling and transport/recycling pathways is required to buffer the loss of CCW12. Moreover, the enrichment of Ccw12p in bud, septum and mating projection is consistent with a role of Ccw12p in preserving cell wall integrity at sites of active growth. The microarray data produced in this analysis have been submitted to NCBI GEO database and GSE22649 record was assigned. PMID:21320323

Antimycobacterial action of a new glycolipid-peptide complex obtained from extracellular metabolites of Raoultella ornithinolytica.

PubMed

Fiołka, Marta J; Grzywnowicz, Krzysztof; Mendyk, Ewaryst; Zagaja, Mirosław; Szewczyk, Rafał; Rawski, Michał; Keller, Radosław; Rzymowska, Jolanta; Wydrych, Jerzy

2015-12-01

In this paper, an antimycobacterial component of extracellular metabolites of a gut bacterium Raoultella ornithinolytica from D. veneta earthworms was isolated and its antimycobacterial action was tested using Mycobacterium smegmatis. After incubation with the complex obtained, formation of pores and furrows in cell walls was observed using microscopic techniques. The cells lost their shape, stuck together and formed clusters. Surface-enhanced Raman spectroscopy analysis showed that, after incubation, the complex was attached to the cell walls of the Mycobacterium. Analyses of the component performed with Fourier transform infrared spectroscopy demonstrated high similarity to a bacteriocin nisin, but energy dispersive X-ray spectroscopy analysis revealed differences in the elemental composition of this antimicrobial peptide. The component with antimycobacterial activity was identified using mass spectrometry techniques as a glycolipid-peptide complex. As it exhibits no cytotoxicity on normal human fibroblasts, the glycolipid-peptide complex appears to be a promising compound for investigations of its activity against pathogenic mycobacteria. © 2015 APMIS. Published by John Wiley & Sons Ltd.

A novel mode of regulation of the Staphylococcus aureus Vancomycin-resistance-associated response regulator VraR mediated by Stk1 protein phosphorylation.

PubMed

Canova, Marc J; Baronian, Grégory; Brelle, Solène; Cohen-Gonsaud, Martin; Bischoff, Markus; Molle, Virginie

2014-04-25

The Staphylococcus aureus Vancomycin-resistance-associated response regulator VraR is known as an important response regulator, member of the VraTSR three-component signal transduction system that modulates the expression of the cell wall stress stimulon in response to a number of different cell wall active antibiotics. Given its crucial role in regulating gene expression in response to antibiotic challenges, VraR must be tightly regulated. We report here for the first time in S. aureus convergence of two major signal transduction systems, serine/threonine protein kinase and two (three)-component systems. We demonstrate that VraR can be phosphorylated by the staphylococcal Ser/Thr protein kinase Stk1 and that phosphorylation negatively affects its DNA-binding properties. Mass spectrometric analyses and site-directed mutagenesis identified Thr106, Thr119, Thr175 and Thr178 as phosphoacceptors. A S. aureus ΔvraR mutant expressing a VraR derivative that mimics constitutive phosphorylation, VraR_Asp, still exhibited markedly decreased antibiotic resistance against different cell wall active antibiotics, when compared to the wild-type, suggesting that VraR phosphorylation may represent a novel and presumably more general mechanism of regulation of the two (three)-component systems in staphylococci. Copyright © 2014 Elsevier Inc. All rights reserved.

VraT/YvqF Is Required for Methicillin Resistance and Activation of the VraSR Regulon in Staphylococcus aureus

PubMed Central

Yin, Shouhui; Jo, Dae Sun; Montgomery, Christopher P.; Daum, Robert S.

2013-01-01

Staphylococcus aureus infections caused by strains that are resistant to all forms of penicillin, so-called methicillin-resistant S. aureus (MRSA) strains, have become common. One strategy to counter MRSA infections is to use compounds that resensitize MRSA to methicillin. S. aureus responds to diverse classes of cell wall-inhibitory antibiotics, like methicillin, using the two-component regulatory system VraSR (vra) to up- or downregulate a set of genes (the cell wall stimulon) that presumably facilitates resistance to these antibiotics. Accordingly, VraS and VraR mutations decrease resistance to methicillin, vancomycin, and daptomycin cell wall antimicrobials. vraS and vraR are encoded together on a transcript downstream of two other genes, which we call vraU and vraT (previously called yvqF). By producing nonpolar deletions in vraU and vraT in a USA300 MRSA clinical isolate, we demonstrate that vraT is essential for optimal expression of methicillin resistance in vitro, whereas vraU is not required for this phenotype. The deletion of vraT also improved the outcomes of oxacillin therapy in mouse models of lung and skin infection. Since vraT expressed in trans did not complement a vra operon deletion, we conclude that VraT does not inactivate the antimicrobial. Genome-wide transcriptional microarray experiments reveal that VraT facilitates resistance by playing a necessary regulatory role in the VraSR-mediated cell wall stimulon. Our data prove that VraTSR comprise a novel three-component regulatory system required to facilitate resistance to cell wall agents in S. aureus. We also provide the first in vivo proof of principle for using VraT as a sole target to resensitize MRSA to β-lactams. PMID:23070169

Physiological and Transcriptional Responses of Saccharomyces cerevisiae to d-Limonene Show Changes to the Cell Wall but Not to the Plasma Membrane

PubMed Central

Brennan, Timothy C. R.; Nielsen, Lars K.

2013-01-01

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. In order to gain a better understanding of the mode of action, we analyzed the composition and structural integrity of the cell envelope as well as the transcriptional response of yeast cells treated with an inhibitory amount of d-limonene (107 mg/liter). 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. Limonene shock did cause a compensatory response to cell wall damage through overexpression of several genes (ROM1, RLM1, PIR3, CTT1, YGP1, MLP1, PST1, and CWP1) involved with the cell wall integrity signaling pathway. 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. PMID:23542628

Arabidopsis and Brachypodium distachyon Transgenic Plants Expressing Aspergillus nidulans Acetylesterases Have Decreased Degree of Polysaccharide Acetylation and Increased Resistance to Pathogens1[C][W][OA

PubMed Central

Pogorelko, Gennady; Lionetti, Vincenzo; Fursova, Oksana; Sundaram, Raman M.; Qi, Mingsheng; Whitham, Steven A.; Bogdanove, Adam J.; Bellincampi, Daniela; Zabotina, Olga A.

2013-01-01

The plant cell wall has many significant structural and physiological roles, but the contributions of the various components to these roles remain unclear. Modification of cell wall properties can affect key agronomic traits such as disease resistance and plant growth. The plant cell wall is composed of diverse polysaccharides often decorated with methyl, acetyl, and feruloyl groups linked to the sugar subunits. In this study, we examined the effect of perturbing cell wall acetylation by making transgenic Arabidopsis (Arabidopsis thaliana) and Brachypodium (Brachypodium distachyon) plants expressing hemicellulose- and pectin-specific fungal acetylesterases. All transgenic plants carried highly expressed active Aspergillus nidulans acetylesterases localized to the apoplast and had significant reduction of cell wall acetylation compared with wild-type plants. Partial deacetylation of polysaccharides caused compensatory up-regulation of three known acetyltransferases and increased polysaccharide accessibility to glycosyl hydrolases. Transgenic plants showed increased resistance to the fungal pathogens Botrytis cinerea and Bipolaris sorokiniana but not to the bacterial pathogens Pseudomonas syringae and Xanthomonas oryzae. These results demonstrate a role, in both monocot and dicot plants, of hemicellulose and pectin acetylation in plant defense against fungal pathogens. PMID:23463782

Ferulic acid: an antioxidant found naturally in plant cell walls and feruloyl esterases involved in its release and their applications.

PubMed

Mathew, Sindhu; Abraham, T Emilia

2004-01-01

Ferulic acid is the most abundant hydroxycinnamic acid in the plant world and maize bran with 3.1% (w/w) ferulic acid is one of the most promising sources of this antioxidant. The dehydrodimers of ferulic acid are important structural components in the plant cell wall and serve to enhance its rigidity and strength. Feruloyl esterases are a subclass of the carboxylic acid esterases that hydrolyze the ester bond between hydroxycinnamic acids and sugars present in plant cell walls and they have been isolated from a wide range of microorganisms, when grown on complex substrates such as cereal brans, sugar beet pulp, pectin and xylan. These enzymes perform a function similar to alkali in the deesterification of plant cell wall and differ in their specificities towards the methyl esters of cinnamic acids and ferulolylated oligosaccharides. They act synergistically with xylanases and pectinases and facilitate the access of hydrolases to the backbone of cell wall polymers. The applications of ferulic acid and feruloyl esterase enzymes are many and varied. Ferulic acid obtained from agricultural byproducts is a potential precursor for the production of natural vanillin, due to the lower production cost.

Transcriptome profiling in Arabidopsis inflorescence stems grown under hypergravity in terms of cell walls and plant hormones

NASA Astrophysics Data System (ADS)

Tamaoki, D.; Karahara, I.; Nishiuchi, T.; De Oliveira, S.; Schreiber, L.; Wakasugi, T.; Yamada, K.; Yamaguchi, K.; Kamisaka, S.

2009-07-01

Land plants rely on lignified secondary cell walls in supporting their body weight on the Earth. Although gravity influences the formation of the secondary cell walls, the regulatory mechanism of their formation by gravity is not yet understood. We carried out a comprehensive analysis of gene expression in inflorescence stems of Arabidopsis thaliana L. using microarray (22 K) to identify genes whose expression is modulated under hypergravity condition (300 g). Total RNA was isolated from the basal region of inflorescence stems of plants grown for 24 h at 300 g or 1 g. Microarray analysis showed that hypergravity up-regulated the expression of 403 genes to more than 2-fold. Hypergravity up-regulated the genes responsible for the biosynthesis or modification of cell wall components such as lignin, xyloglucan, pectin and structural proteins. In addition, hypergravity altered the expression of genes related to the biosynthesis of plant hormones such as auxin and ethylene and that of genes encoding hormone-responsive proteins. Our transcriptome profiling indicates that hypergravity influences the formation of secondary cell walls by modulating the pattern of gene expression, and that auxin and/or ethylene play an important role in signaling hypergravity stimulus.

Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants

PubMed Central

Li, Shundai; Bashline, Logan; Zheng, Yunzhen; Xin, Xiaoran; Huang, Shixin; Kong, Zhaosheng; Kim, Seong H.; Cosgrove, Daniel J.; Gu, Ying

2016-01-01

Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana. This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs. PMID:27647923

Cellulose synthase complexes act in a concerted fashion to synthesize highly aggregated cellulose in secondary cell walls of plants.

PubMed

Li, Shundai; Bashline, Logan; Zheng, Yunzhen; Xin, Xiaoran; Huang, Shixin; Kong, Zhaosheng; Kim, Seong H; Cosgrove, Daniel J; Gu, Ying

2016-10-04

Cellulose, often touted as the most abundant biopolymer on Earth, is a critical component of the plant cell wall and is synthesized by plasma membrane-spanning cellulose synthase (CESA) enzymes, which in plants are organized into rosette-like CESA complexes (CSCs). Plants construct two types of cell walls, primary cell walls (PCWs) and secondary cell walls (SCWs), which differ in composition, structure, and purpose. Cellulose in PCWs and SCWs is chemically identical but has different physical characteristics. During PCW synthesis, multiple dispersed CSCs move along a shared linear track in opposing directions while synthesizing cellulose microfibrils with low aggregation. In contrast, during SCW synthesis, we observed swaths of densely arranged CSCs that moved in the same direction along tracks while synthesizing cellulose microfibrils that became highly aggregated. Our data support a model in which distinct spatiotemporal features of active CSCs during PCW and SCW synthesis contribute to the formation of cellulose with distinct structure and organization in PCWs and SCWs of Arabidopsis thaliana This study provides a foundation for understanding differences in the formation, structure, and organization of cellulose in PCWs and SCWs.

Constitutive expression of cell wall invertase genes increases grain yield and starch content in maize.

PubMed

Li, Bei; Liu, Hua; Zhang, Yue; Kang, Tao; Zhang, Li; Tong, Jianhua; Xiao, Langtao; Zhang, Hongxia

2013-12-01

Grain size, number and starch content are important determinants of grain yield and quality. One of the most important biological processes that determine these components is the carbon partitioning during the early grain filling, which requires the function of cell wall invertase. Here, we showed the constitutive expression of cell wall invertase-encoding gene from Arabidopsis, rice (Oryza sativa) or maize (Zea mays), driven by the cauliflower mosaic virus (CaMV) 35S promoter, all increased cell wall invertase activities in different tissues and organs, including leaves and developing seeds, and substantially improved grain yield up to 145.3% in transgenic maize plants as compared to the wild-type plants, an effect that was reproduced in our 2-year field trials at different locations. The dramatically increased grain yield is due to the enlarged ears with both enhanced grain size and grain number. Constitutive expression of the invertase-encoding gene also increased total starch content up to 20% in the transgenic kernels. Our results suggest that cell wall invertase gene can be genetically engineered to improve both grain yield and grain quality in crop plants. © 2013 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Endometrial stromal cell attachment and matrix homeostasis in abdominal wall endometriomas.

PubMed

Itoh, Hiroko; Mogami, Haruta; Bou Nemer, Laurice; Word, Larry; Rogers, David; Miller, Rodney; Word, R Ann

2018-02-01

How does progesterone alter matrix remodeling in abdominal wall endometriomas compared with normal endometrium? Progesterone may prevent attachment of endometrial cells to the abdominal wall, but does not ameliorate abnormal stromal cell responses of abdominal wall endometriomas. Menstruation is a tightly orchestrated physiologic event in which steroid hormones and inflammatory cells cooperatively initiate shedding of the endometrium. Abdominal wall endometriomas represent a unique form of endometriosis in which endometrial cells inoculate fascia or dermis at the time of obstetrical or gynecologic surgery. Invasion of endometrium into ectopic sites requires matrix metalloproteinases (MMPs) for tissue remodeling but endometrium is not shed externally. Observational study in 14 cases and 19 controls. Tissues and stromal cells isolated from 14 abdominal wall endometriomas were compared with 19 normal cycling endometrium using immunohistochemistry, quantitative PCR, gelatin zymography and cell attachment assays. P values < 0.05 were considered significant and experiments were repeated in at least three different cell preps to provide scientific rigor to the conclusions. The results indicate that MMP2 and MMP9 are not increased by TGFβ1 in endometrioma stromal cells. Although progesterone prevents attachment of endometrioma cells to matrix components of the abdominal wall, it does not ameliorate these abnormal stromal cell responses to TGFβ1. N/A. Endometriomas were collected from women identified pre-operatively. Not all endometriomas were collected. Stromal cells from normal endometrium were from different patients, not women undergoing endometrioma resection. This work provides insight into the mechanisms by which progesterone may prevent abdominal wall endometriomas but, once established, are refractory to progesterone treatment. Tissue acquisition was supported by NIH P01HD087150. Authors have no competing interests. © The Author(s) 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Characterization of Cell Wall Components and Their Modifications during Postharvest Storage of Asparagus officinalis L.: Storage-Related Changes in Dietary Fiber Composition.

PubMed

Schäfer, Judith; Wagner, Steffen; Trierweiler, Bernhard; Bunzel, Mirko

2016-01-20

Changes in cell wall composition during storage of plant foods potentially alter the physiological effects of dietary fiber components. To investigate postharvest cell wall modifications of asparagus and their consequences in terms of insoluble dietary fiber structures, asparagus was stored at 20 and 1 °C for different periods of time. Structural analyses demonstrated postharvest changes in the polysaccharide profile, dominated by decreased portions of galactans. Increasing lignin contents correlated with compositional changes (monolignol ratios and linkage types) of the lignin polymer as demonstrated by chemical and two-dimensional nuclear magnetic resonance (2D-NMR) methods. Depending on the storage time and temperature, syringyl units were preferentially incorporated into the lignin polymer. Furthermore, a drastic increase in the level of ester-linked phenolic monomers (i.e., p-coumaric acid and ferulic acid) and polymer cross-links (di- and triferulic acids) was detected. The attachment of p-coumaric acid to lignin was demonstrated by 2D-NMR experiments. Potential consequences of postharvest modifications on physiological effects of asparagus dietary fiber are discussed.

Glucuronoarabinoxylans as major cell walls polymers from young shoots of the woody bamboo Phyllostachys aurea.

PubMed

Zelaya, Víctor Martín; Fernández, Paula Virginia; Vega, Andrea Susana; Mantese, Anita Ida; Federico, Ana Ailén; Ciancia, Marina

2017-07-01

Young shoots of Phyllostachys aurea showed glucuronoarabinoxylans (GAX) as the major hemicellulosic components, being extracted in major amounts with 1M KOH (ratio Xyl:Ara:GlcA, 100:67:8), but also with water, showing a broad structural variability. Mixed linkage glucans were also present, but in minor amounts, mostly concentrated in the 4M KOH extracts, while pectin polymers were very scarce. Arabinogalactan proteins were an important part of water extracts, determined by the presence of the typical arabinogalactan structures (3- and 6-linked Gal p; terminal and 5-linked Ara f), in addition to small amounts of hydroxyproline (2-3% of total protein) and positive reaction to Yariv's reagent. Morphological and anatomical characteristics of young shoots are described, as well as localization of some cell wall components, and related with chemical analysis. A method for determination of uronic acids as their N-propylaldonamide acetates and separation and quantification by GC/MS was adapted for its use with grass cell wall fractions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Evidence for Proinflammatory β-1,6 Glucans in the Pneumocystis carinii Cell Wall

PubMed Central

Kottom, Theodore J.; Hebrink, Deanne M.; Jenson, Paige E.; Gudmundsson, Gunnar

2015-01-01

Inflammation is a major cause of respiratory impairment during Pneumocystis pneumonia. Studies support a significant role for cell wall β-glucans in stimulating inflammatory responses. Fungal β-glucans are comprised of d-glucose homopolymers containing β-1,3-linked glucose backbones with β-1,6-linked glucose side chains. Prior studies in Pneumocystis carinii have characterized β-1,3 glucan components of the organism. However, recent investigations in other organisms support important roles for β-1,6 glucans, predominantly in mediating host cellular activation. Accordingly, we sought to characterize β-1,6 glucans in the cell wall of Pneumocystis and to establish their activity in lung cell inflammation. Immune staining revealed specific β-1,6 localization in P. carinii cyst walls. Homology-based cloning facilitated characterization of a functional P. carinii kre6 (Pckre6) β-1,6 glucan synthase in Pneumocystis that, when expressed in kre6-deficient Saccharomyces cerevisiae, restored cell wall stability. Recently synthesized β-1,6 glucan synthase inhibitors decreased the ability of isolated P. carinii preparations to generate β-1,6 carbohydrate. In addition, isolated β-1,6 glucan fractions from Pneumocystis elicited vigorous tumor necrosis factor alpha (TNF-α) responses from macrophages. These inflammatory responses were significantly dampened by inhibition of host cell plasma membrane microdomain function. Together, these studies indicate that β-1,6 glucans are present in the P. carinii cell wall and contribute to lung cell inflammatory activation during infection. PMID:25916991

The MAPKK FgMkk1 of Fusarium graminearum regulates vegetative differentiation, multiple stress response, and virulence via the cell wall integrity and high-osmolarity glycerol signaling pathways.

PubMed

Yun, Yingzi; Liu, Zunyong; Zhang, Jingze; Shim, Won-Bo; Chen, Yun; Ma, Zhonghua

2014-07-01

Mitogen-activated protein (MAP) kinases play crucial roles in regulating fungal development, growth and pathogenicity, and in responses to the environment. In this study, we characterized a MAP kinase kinase FgMkk1 in Fusarium graminearum, the causal agent of wheat head blight. Phenotypic analyses of the FgMKK1 mutant (ΔFgMKK1) showed that FgMkk1 is involved in the regulation of hyphal growth, pigmentation, conidiation, deoxynivalenol biosynthesis and virulence of F. graminearum. ΔFgMKK1 also showed increased sensitivity to cell wall-damaging agents, and to osmotic and oxidative stresses, but exhibited decreased sensitivity to the fungicides iprodione and fludioxonil. In addition, the mutant revealed increased sensitivity to a biocontrol agent, Trichoderma atroviride. Western blot assays revealed that FgMkk1 positively regulates phosphorylation of the MAP kinases Mgv1 and FgOs-2, the key component in the cell wall integrity (CWI) and high-osmolarity glycerol (HOG) signalling pathway respectively. Yeast two-hybrid assay indicated that Mgv1 interacts with a transcription factor FgRlm1. The FgRLM1 mutant (ΔFgRLM1) showed increased sensitivity to cell wall-damaging agents and exhibited decreased virulence. Taken together, our data indicated that FgMkk1 is an upstream component of Mgv1, and regulates vegetative differentiation, multiple stress response and virulence via the CWI and HOG signalling pathways. FgRlm1 may be a downstream component of Mgv1 in the CWI pathway in F. graminearum. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

Vitronectin and fibronectin function as glucan binding proteins augmenting macrophage responses to Pneumocystis carinii.

PubMed

Vassallo, R; Kottom, T J; Standing, J E; Limper, A H

2001-08-01

beta-glucans represent major structural components of fungal cell walls. We recently reported that Pneumocystis carinii beta-glucans stimulate alveolar macrophages to release proinflammatory cytokines. Macrophage activation by beta-glucan is augmented by serum, implying the presence of circulating factors that interact with beta-glucans and enhance their ability to stimulate macrophages. Using beta-glucan-enriched cell wall fractions from P. carinii and Saccharomyces cerevisiae, two prominent proteins were precipitated from serum and demonstrated to be vitronectin (VN) and fibronectin (FN) by immune analysis. Preincubation of beta-glucan with VN or FN enhanced macrophage activation in response to this cell wall component. Because VN and FN accumulate in the lungs during P. carinii pneumonia, we further investigated hepatic and pulmonary expression of VN and FN messenger RNA during infection. P. carinii pneumonia in rodents is associated with increased hepatic expression of VN and FN as well as increased local expression of FN in the lung. Because interleukin (IL)-6 represents the major regulator of VN and FN expression during inflammatory conditions, we measured macrophage IL-6 release in response to stimulation with P. carinii beta-glucan. Stimulation of macrophages with P. carinii beta-glucan induced significant release of IL-6. Elevated concentrations of IL-6 were noted in the blood of infected animals compared with uninfected control animals. These studies indicate that VN and FN bind to beta-glucan components of P. carinii and augment macrophage inflammatory responses. P. carinii cell wall beta-glucan stimulates secretion of IL-6 by macrophages, thereby enhancing hepatic synthesis of both VN and FN, and lung synthesis of FN during pneumonia.

Cellular metabolic responses of the marine diatom Pseudo-nitzschia multiseries associated with cell wall formation.

PubMed

Xu, Bin; Luo, Chun-Shan; Liang, Jun-Rong; Chen, Dan-Dan; Zhuo, Wen-Hao; Gao, Ya-Hui; Chen, Chang-Ping; Song, Si-Si

2014-08-01

In this study a comparative proteomics approach involving a mass spectrometric analysis of synchronized cells was employed to investigate the cellular-level metabolic mechanisms associated with siliceous cell wall formation in the pennate diatom Pseudo-nitzschia multiseries. Cultures of P. multiseries were synchronized using the silicate limitation method. Approximately 75% of cells were arrested at the G2+M phase of the cell cycle after 48 h of silicate starvation. The majority of cells progressed to new valve synthesis within 5h of silicon replenishment. We compared the proteome of P. multiseries at 0, 4, 5, and 6h of synchronization progress upon silicon replenishment using two-dimensional gel electrophoresis. Forty-eight differentially expressed protein spots were identified in abundance (greater than two-fold change; P<0.005), some of which are predicted to be involved in intracellular trafficking, cytoskeleton, photosynthesis, lipid metabolism, and protein biosynthesis. Cytoskeleton proteins and clathrin coat components were also hypothesized to play potential roles in cell wall formation. The proteomic profile analysis suggests that P. multiseries most likely employs multiple synergistic biochemical mechanisms for cell wall formation. These results improve our understanding of the molecular mechanisms underlying silicon cell wall formation and enhance our understanding of the important role played by diatoms in silicon biogeochemical cycling. Copyright © 2013 Elsevier B.V. All rights reserved.

ELECTRON MICROSCOPE STUDY OF MYCOBACTERIUM LEPRAE AND ITS ENVIRONMENT IN A VESICULAR LEPROUS LESION

PubMed Central

Imaeda, Tamotsu; Convit, Jacinto

1962-01-01

Imaeda, Tamotsu (Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela) and Jacinto Convit. Electron microscope study of Mycobacterium leprae and its environment in a vesicular leprous lesion. J. Bacteriol. 83:43–52. 1962.—Biopsied specimens of a borderline leprosy lesion were observed with the electron microscope. In this lesion, the majority of Mycobacterium leprae were laden with cytoplasmic components. The bacilli were separated from the cytoplasm of host cells by an enclosing membrane, thus differing from the environment of well-developed lepra cells in lepromatous lesions. The cell wall is composed of a moderately dense layer. A diffuse layer is discernible outside the cell wall, separated from it by a low density space. It is suggested that the cell wall is further coated by a low density layer, although the nature of the outermost diffuse layer has not yet been determined. The plasma membrane consists of a double layer, i.e., dense inner and outer layers separated by a low density space. The outer layer is closely adjacent to the cell wall. In the region where the outer layer of the plasma membrane enters the cytoplasm and is transformed into a complex membranous structure, the inner layer encloses this membranous configuration. Together they form the intracytoplasmic membrane system. In the bacterial cytoplasm, moderately dense, presumably polyphosphate bodies are apparent. As neither these bodies nor the intracytoplasmic membrane system are visible in the degenerating bacilli, it seems probable that these two components represent indicators of the state of bacillary activity. Images PMID:16561926

The GLABRA2 homeodomain protein directly regulates CESA5 and XTH17 gene expression in Arabidopsis roots.

PubMed

Tominaga-Wada, Rumi; Iwata, Mineko; Sugiyama, Junji; Kotake, Toshihisa; Ishida, Tetsuya; Yokoyama, Ryusuke; Nishitani, Kazuhiko; Okada, Kiyotaka; Wada, Takuji

2009-11-01

Arabidopsis root hair formation is determined by the patterning genes CAPRICE (CPC), GLABRA3 (GL3), WEREWOLF (WER) and GLABRA2 (GL2), but little is known about the later changes in cell wall material during root hair formation. A combined Fourier-transform infrared microspectroscopy-principal components analysis (FTIR-PCA) method was used to detect subtle differences in the cell wall material between wild-type and root hair mutants in Arabidopsis. Among several root hair mutants, only the gl2 mutation affected root cell wall polysaccharides. Five of the 10 genes encoding cellulose synthase (CESA1-10) and 4 of 33 xyloglucan endotransglucosylase (XTH1-33) genes in Arabidopsis are expressed in the root, but only CESA5 and XTH17 were affected by the gl2 mutation. The L1-box sequence located in the promoter region of these genes was recognized by the GL2 protein. These results indicate that GL2 directly regulates cell wall-related gene expression during root development.

Regulation of expression, activity and localization of fungal chitin synthases

PubMed Central

Rogg, Luise E.; Fortwendel, Jarrod R.; Juvvadi, Praveen R.; Steinbach, William J.

2013-01-01

The fungal cell wall represents an attractive target for pharmacologic inhibition, as many of the components are fungal-specific. Though targeted inhibition of β-glucan synthesis is effective treatment for certain fungal infections, the ability of the cell wall to dynamically compensate via the cell wall integrity pathway may limit overall efficacy. To date, chitin synthesis inhibitors have not been successfully deployed in the clinical setting. Fungal chitin synthesis is a complex and highly regulated process. Regulation of chitin synthesis occurs on multiple levels, thus targeting of these regulatory pathways may represent an exciting alternative approach. A variety of signaling pathways have been implicated in chitin synthase regulation, at both transcriptional and post-transcriptional levels. Recent research suggests that localization of chitin synthases likely represents a major regulatory mechanism. However, much of the regulatory machinery is not necessarily shared among different chitin synthases. Thus, an in depth understanding of the precise roles of each protein in cell wall maintenance and repair will be essential to identifying the most likely therapeutic targets. PMID:21526913

Effects of commercial pectolytic and cellulolytic enzyme preparations on the apple cell wall.

PubMed

Dongowski, G; Sembries, S

2001-09-01

The action of three different commercial enzyme combinations on apple cell wall material has been examined in a model system under conditions of mash and pomace treatment by using an alcohol-insoluble substance prepared from apples. A part of the total dietary fiber, for example, galacturonan (pectin), appeared in the soluble fraction after enzymatic mash treatment. The soluble fraction increased intensely during pomace treatment. Furthermore, enzyme actions caused a change in the water-binding capacity of residues as well as changes in the monosaccharide composition and in the molecular weight distribution of saccharides in filtrates (soluble parts). The extent of decomposition of cell wall material and the increase of soluble oligomeric and/or polymeric dietary fiber components are caused by both the composition (pectinases, cellulases, and hemicellulases) and the activities of the enzyme preparations. The model experiments allow an insight into the reactions occurring during enzyme action on the plant cell wall, for example, during apple juice production using pectolytic and cellulolytic enzyme preparations.

Deletion of the α-(1,3)-Glucan Synthase Genes Induces a Restructuring of the Conidial Cell Wall Responsible for the Avirulence of Aspergillus fumigatus

PubMed Central

Beauvais, Anne; Bozza, Silvia; Kniemeyer, Olaf; Formosa, Céline; Balloy, Viviane; Henry, Christine; Roberson, Robert W.; Dague, Etienne; Chignard, Michel; Brakhage, Axel A.; Romani, Luigina; Latgé, Jean-Paul

2013-01-01

α-(1,3)-Glucan is a major component of the cell wall of Aspergillus fumigatus, an opportunistic human fungal pathogen. There are three genes (AGS1, AGS2 and AGS3) controlling the biosynthesis of α-(1,3)-glucan in this fungal species. Deletion of all the three AGS genes resulted in a triple mutant that was devoid of α-(1,3)-glucan in its cell wall; however, its growth and germination was identical to that of the parental strain in vitro. In the experimental murine aspergillosis model, this mutant was less pathogenic than the parental strain. The AGS deletion resulted in an extensive structural modification of the conidial cell wall, especially conidial surface where the rodlet layer was covered by an amorphous glycoprotein matrix. This surface modification was responsible for viability reduction of conidia in vivo, which explains decrease in the virulence of triple agsΔ mutant. PMID:24244155

Cell-wall disruption and lipid/astaxanthin extraction from microalgae: Chlorella and Haematococcus.

PubMed

Kim, Dong-Yeon; Vijayan, Durairaj; Praveenkumar, Ramasamy; Han, Jong-In; Lee, Kyubock; Park, Ji-Yeon; Chang, Won-Seok; Lee, Jin-Suk; Oh, You-Kwan

2016-01-01

Recently, biofuels and nutraceuticals produced from microalgae have emerged as major interests, resulting in intensive research of the microalgal biorefinery process. In this paper, recent developments in cell-wall disruption and extraction methods are reviewed, focusing on lipid and astaxanthin production from the biotechnologically important microalgae Chlorella and Haematococcus, respectively. As a common, critical bottleneck for recovery of intracellular components such as lipid and astaxanthin from these microalgae, the composition and structure of rigid, thick cell-walls were analyzed. Various chemical, physical, physico-chemical, and biological methods applied for cell-wall breakage and lipid/astaxanthin extraction from Chlorella and Haematococcus are discussed in detail and compared based on efficiency, energy consumption, type and dosage of solvent, biomass concentration and status (wet/dried), toxicity, scalability, and synergistic combinations. This report could serve as a useful guide to the implementation of practical downstream processes for recovery of valuable products from microalgae including Chlorella and Haematococcus. Copyright © 2015 Elsevier Ltd. All rights reserved.

Potential for utilization of algal biomass for components of the diet in CELSS

NASA Technical Reports Server (NTRS)

Kamarei, A. R.; Nakhost, Z.; Karel, M.

1985-01-01

Techniques which eliminate or reduce the undesirable cell components of algae and enhance the potential nutritional and organoleptic acceptability of algae products are studied. The cell walls, nucleic acids, and pigments and lipids of the green algae Scenedesmus obiliquus need to be removed. The procedures for determining the composition of proteins, pigments and lipids, and moisture and ash are described. Chemical, enzymatic, and physical methods of removing the cell wall to make the algae digestable are analyzed; a homogenization technique is utilized. The problems encountered if algae nucleic acids are ingested directly are discussed; the reduction of DNA and RNA by applying extracellular DNase and RNase to the nucleic acids is examined. The color and flavor of the algae are enhanced with the extraction of pigments and lipids from the algae protein concentration.

Identification of an algal xylan synthase indicates that there is functional orthology between algal and plant cell wall biosynthesis

DOE PAGES

Jensen, Jacob Kruger; Busse-Wicher, Marta; Poulsen, Christian Peter; ...

2018-02-20

Insights into the evolution of plant cell walls have important implications for comprehending these diverse and abundant biological structures. In order to understand the evolving structure-function relationships of the plant cell wall, it is imperative to trace the origin of its different components. The present study is focused on plant 1,4-β-xylan, tracing its evolutionary origin by genome and transcriptome mining followed by phylogenetic analysis, utilizing a large selection of plants and algae. It substantiates the findings by heterologous expression and biochemical characterization of a charophyte alga xylan synthase. Of the 12 known gene classes involved in 1,4-β-xylan formation, XYS1/IRX10 inmore » plants, IRX7, IRX8, IRX9, IRX14 and GUX occurred for the first time in charophyte algae. An XYS1/IRX10 ortholog from Klebsormidium flaccidum, designated K. flaccidumXYLAN SYNTHASE-1 (KfXYS1), possesses 1,4-β-xylan synthase activity, and 1,4-β-xylan occurs in the K. flaccidum cell wall. Finally, these data suggest that plant 1,4-β-xylan originated in charophytes and shed light on the origin of one of the key cell wall innovations to occur in charophyte algae, facilitating terrestrialization and emergence of polysaccharide-based plant cell walls.« less

Identification of an algal xylan synthase indicates that there is functional orthology between algal and plant cell wall biosynthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jensen, Jacob Kruger; Busse-Wicher, Marta; Poulsen, Christian Peter

Insights into the evolution of plant cell walls have important implications for comprehending these diverse and abundant biological structures. In order to understand the evolving structure-function relationships of the plant cell wall, it is imperative to trace the origin of its different components. The present study is focused on plant 1,4-β-xylan, tracing its evolutionary origin by genome and transcriptome mining followed by phylogenetic analysis, utilizing a large selection of plants and algae. It substantiates the findings by heterologous expression and biochemical characterization of a charophyte alga xylan synthase. Of the 12 known gene classes involved in 1,4-β-xylan formation, XYS1/IRX10 inmore » plants, IRX7, IRX8, IRX9, IRX14 and GUX occurred for the first time in charophyte algae. An XYS1/IRX10 ortholog from Klebsormidium flaccidum, designated K. flaccidumXYLAN SYNTHASE-1 (KfXYS1), possesses 1,4-β-xylan synthase activity, and 1,4-β-xylan occurs in the K. flaccidum cell wall. Finally, these data suggest that plant 1,4-β-xylan originated in charophytes and shed light on the origin of one of the key cell wall innovations to occur in charophyte algae, facilitating terrestrialization and emergence of polysaccharide-based plant cell walls.« less

Acetylation of cell wall is required for structural integrity of the leaf surface and exerts a global impact on plant stress responses

DOE PAGES

Nafisi, Majse; Stranne, Maria; Fimognari, Lorenzo; ...

2015-07-22

Here we report that the epidermis on leaves protects plants from pathogen invasion and provides a waterproof barrier. It consists of a layer of cells that is surrounded by thick cell walls, which are partially impregnated by highly hydrophobic cuticular components. We show that the Arabidopsis T-DNA insertion mutants of REDUCED WALL ACETYLATION 2 (rwa2), previously identified as having reduced O-acetylation of both pectins and hemicelluloses, exhibit pleiotrophic phenotype on the leaf surface. The cuticle layer appeared diffused and was significantly thicker and underneath cell wall layer was interspersed with electron-dense deposits. A large number of trichomes were collapsed andmore » surface permeability of the leaves was enhanced in rwa2 as compared to the wild type. A massive reprogramming of the transcriptome was observed in rwa2 as compared to the wild type, including a coordinated up-regulation of genes involved in responses to abiotic stress, particularly detoxification of reactive oxygen species and defense against microbial pathogens (e.g., lipid transfer proteins, peroxidases). In accordance, peroxidase activities were found to be elevated in rwa2 as compared to the wild type. These results indicate that cell wall acetylation is essential for maintaining the structural integrity of leaf epidermis, and that reduction of cell wall acetylation leads to global stress responses in Arabidopsis.« less

Visualizing lignin coalescence and migration through maize cell walls following thermochemical pretreatment.

PubMed

Donohoe, Bryon S; Decker, Stephen R; Tucker, Melvin P; Himmel, Michael E; Vinzant, Todd B

2008-12-01

Plant cell walls are composed primarily of cellulose, hemicelluloses, lignins, and pectins. Of these components, lignins exhibit unique chemistry and physiological functions. Although lignins can be used as a product feedstock or as a fuel, lignins are also generally seen as a barrier to efficient enzymatic breakdown of biomass to sugars. Indeed, many pretreatment strategies focus on removing a significant fraction of lignin from biomass to better enable saccharification. In order to better understand the fate of biomass lignins that remain with the solids following dilute acid pretreatment, we undertook a structural investigation to track lignins on and in biomass cell walls. SEM and TEM imaging revealed a range of droplet morphologies that appear on and within cell walls of pretreated biomass; as well as the specific ultrastructural regions that accumulate the droplets. These droplets were shown to contain lignin by FTIR, NMR, antibody labeling, and cytochemical staining. We provide evidence supporting the idea that thermochemical pretreatments reaching temperatures above the range for lignin phase transition cause lignins to coalesce into larger molten bodies that migrate within and out of the cell wall, and can redeposit on the surface of plant cell walls. This decompartmentalization and relocalization of lignins is likely to be at least as important as lignin removal in the quest to improve the digestibility of biomass for sugars and fuels production.

Subcellular analysis by laser ablation electrospray ionization mass spectrometry

DOEpatents

Vertes, Akos; Stolee, Jessica A; Shrestha, Bindesh

2014-12-02

In various embodiments, a method of laser ablation electrospray ionization mass spectrometry (LAESI-MS) may generally comprise micro-dissecting a cell comprising at least one of a cell wall and a cell membrane to expose at least one subcellular component therein, ablating the at least one subcellular component by an infrared laser pulse to form an ablation plume, intercepting the ablation plume by an electrospray plume to form ions, and detecting the ions by mass spectrometry.

Transcriptomic analysis of Arabidopsis developing stems: a close-up on cell wall genes

PubMed Central

Minic, Zoran; Jamet, Elisabeth; San-Clemente, Hélène; Pelletier, Sandra; Renou, Jean-Pierre; Rihouey, Christophe; Okinyo, Denis PO; Proux, Caroline; Lerouge, Patrice; Jouanin, Lise

2009-01-01

Background Different strategies (genetics, biochemistry, and proteomics) can be used to study proteins involved in cell biogenesis. The availability of the complete sequences of several plant genomes allowed the development of transcriptomic studies. Although the expression patterns of some Arabidopsis thaliana genes involved in cell wall biogenesis were identified at different physiological stages, detailed microarray analysis of plant cell wall genes has not been performed on any plant tissues. Using transcriptomic and bioinformatic tools, we studied the regulation of cell wall genes in Arabidopsis stems, i.e. genes encoding proteins involved in cell wall biogenesis and genes encoding secreted proteins. Results Transcriptomic analyses of stems were performed at three different developmental stages, i.e., young stems, intermediate stage, and mature stems. Many genes involved in the synthesis of cell wall components such as polysaccharides and monolignols were identified. A total of 345 genes encoding predicted secreted proteins with moderate or high level of transcripts were analyzed in details. The encoded proteins were distributed into 8 classes, based on the presence of predicted functional domains. Proteins acting on carbohydrates and proteins of unknown function constituted the two most abundant classes. Other proteins were proteases, oxido-reductases, proteins with interacting domains, proteins involved in signalling, and structural proteins. Particularly high levels of expression were established for genes encoding pectin methylesterases, germin-like proteins, arabinogalactan proteins, fasciclin-like arabinogalactan proteins, and structural proteins. Finally, the results of this transcriptomic analyses were compared with those obtained through a cell wall proteomic analysis from the same material. Only a small proportion of genes identified by previous proteomic analyses were identified by transcriptomics. Conversely, only a few proteins encoded by genes having moderate or high level of transcripts were identified by proteomics. Conclusion Analysis of the genes predicted to encode cell wall proteins revealed that about 345 genes had moderate or high levels of transcripts. Among them, we identified many new genes possibly involved in cell wall biogenesis. The discrepancies observed between results of this transcriptomic study and a previous proteomic study on the same material revealed post-transcriptional mechanisms of regulation of expression of genes encoding cell wall proteins. PMID:19149885

Changes in apoplastic peroxidase activity and cell wall composition are associated with cold-induced morpho-anatomical plasticity of wheat leaves.

PubMed

Lorenzo, M; Pinedo, M L; Equiza, M A; Fernández, P V; Ciancia, M; Ganem, D G; Tognetti, J A

2018-02-14

Temperate grasses, such as wheat, become compact plants with small thick leaves after exposure to low temperature. These responses are associated with cold hardiness, but their underlying mechanisms remain largely unknown. Here we analyse the effects of low temperature on leaf morpho-anatomical structure, cell wall composition and activity of extracellular peroxidases, which play key roles in cell elongation and cell wall thickening, in two wheat cultivars with contrasting cold-hardening ability. A combined microscopy and biochemical approach was applied to study actively growing leaves of winter (ProINTA-Pincén) and spring (Buck-Patacón) wheat developed under constant warm (25 °C) or cool (5 °C) temperature. Cold-grown plants had shorter leaves but longer inter-stomatal epidermal cells than warm-grown plants. They had thicker walls in metaxylem vessels and mestome sheath cells, paralleled with accumulation of wall components, predominantly hemicellulose. These effects were more pronounced in the winter cultivar (Pincén). Cold also induced a sharp decrease in apoplastic peroxidase activity within the leaf elongating zone of Pincén, and a three-fold increase in the distal mature zone of the leaf. This was consistent with the enhanced cell length and thicker cell walls in this cultivar at 5 °C. The different response to low temperature of apoplastic peroxidase activity and hemicellulose between leaf zones and cultivar types suggests they might play a central role in the development of cold-induced compact morphology and cold hardening. New insights are presented on the potential temperature-driven role of peroxidases and hemicellulose in cell wall dynamics of grasses. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

A Novel Plasma Membrane-Anchored Protein Regulates Xylem Cell-Wall Deposition through Microtubule-Dependent Lateral Inhibition of Rho GTPase Domains.

PubMed

Sugiyama, Yuki; Wakazaki, Mayumi; Toyooka, Kiminori; Fukuda, Hiroo; Oda, Yoshihisa

2017-08-21

Spatial control of cell-wall deposition is essential for determining plant cell shape [1]. Rho-type GTPases, together with the cortical cytoskeleton, play central roles in regulating cell-wall patterning [2]. In metaxylem vessel cells, which are the major components of xylem tissues, active ROP11 Rho GTPases form oval plasma membrane domains that locally disrupt cortical microtubules, thereby directing the formation of oval pits in secondary cell walls [3-5]. However, the regulatory mechanism that determines the planar shape of active Rho of Plants (ROP) domains is still unknown. Here we show that IQD13 associates with cortical microtubules and the plasma membrane to laterally restrict the localization of ROP GTPase domains, thereby directing the formation of oval secondary cell-wall pits. Loss and overexpression of IQD13 led to the formation of abnormally round and narrow secondary cell-wall pits, respectively. Ectopically expressed IQD13 increased the presence of parallel cortical microtubules by promoting microtubule rescue. A reconstructive approach revealed that IQD13 confines the area of active ROP domains within the lattice of the cortical microtubules, causing narrow ROP domains to form. This activity required the interaction of IQD13 with the plasma membrane. These findings suggest that IQD13 positively regulates microtubule dynamics as well as their linkage to the plasma membrane, which synergistically confines the area of active ROP domains, leading to the formation of oval secondary cell-wall pits. This finding sheds light on the role of microtubule-plasma membrane linkage as a lateral fence that determines the planar shape of Rho GTPase domains. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatial gradients in cell wall composition and transcriptional profiles along elongating maize internodes

PubMed Central

2014-01-01

Background The elongating maize internode represents a useful system for following development of cell walls in vegetative cells in the Poaceae family. Elongating internodes can be divided into four developmental zones, namely the basal intercalary meristem, above which are found the elongation, transition and maturation zones. Cells in the basal meristem and elongation zones contain mainly primary walls, while secondary cell wall deposition accelerates in the transition zone and predominates in the maturation zone. Results The major wall components cellulose, lignin and glucuronoarabinoxylan (GAX) increased without any abrupt changes across the elongation, transition and maturation zones, although GAX appeared to increase more between the elongation and transition zones. Microarray analyses show that transcript abundance of key glycosyl transferase genes known to be involved in wall synthesis or re-modelling did not match the increases in cellulose, GAX and lignin. Rather, transcript levels of many of these genes were low in the meristematic and elongation zones, quickly increased to maximal levels in the transition zone and lower sections of the maturation zone, and generally decreased in the upper maturation zone sections. Genes with transcript profiles showing this pattern included secondary cell wall CesA genes, GT43 genes, some β-expansins, UDP-Xylose synthase and UDP-Glucose pyrophosphorylase, some xyloglucan endotransglycosylases/hydrolases, genes involved in monolignol biosynthesis, and NAM and MYB transcription factor genes. Conclusions The data indicated that the enzymic products of genes involved in cell wall synthesis and modification remain active right along the maturation zone of elongating maize internodes, despite the fact that corresponding transcript levels peak earlier, near or in the transition zone. PMID:24423166

Expression of mung bean pectin acetyl esterase in potato tubers: effect on acetylation of cell wall polymers and tuber mechanical properties.

PubMed

Orfila, Caroline; Dal Degan, Florence; Jørgensen, Bodil; Scheller, Henrik Vibe; Ray, Peter M; Ulvskov, Peter

2012-07-01

A mung bean (Vigna radiata) pectin acetyl esterase (CAA67728) was heterologously expressed in tubers of potato (Solanum tuberosum) under the control of the granule-bound starch synthase promoter or the patatin promoter in order to probe the significance of O-acetylation on cell wall and tissue properties. The recombinant tubers showed no apparent macroscopic phenotype. The enzyme was recovered from transgenic tubers using a high ionic strength buffer and the extract was active against a range of pectic substrates. Partial in vivo de-acetylation of cell wall polysaccharides occurred in the transformants, as shown by a 39% decrease in the degree of acetylation (DA) of tuber cell wall material (CWM). Treatment of CWM using a combination of endo-polygalacturonase and pectin methyl esterase extracted more pectin polymers from the transformed tissue compared to wild type. The largest effect of the pectin acetyl esterase (68% decrease in DA) was seen in the residue from this extraction, suggesting that the enzyme is preferentially active on acetylated pectin that is tightly bound to the cell wall. The effects of acetylation on tuber mechanical properties were investigated by tests of failure under compression and by determination of viscoelastic relaxation spectra. These tests suggested that de-acetylation resulted in a stiffer tuber tissue and a stronger cell wall matrix, as a result of changes to a rapidly relaxing viscoelastic component. These results are discussed in relation to the role of pectin acetylation in primary cell walls and its implications for industrial uses of potato fibres.

A specialized outer layer of the primary cell wall joins elongating cotton fibers into tissue-like bundles.

PubMed

Singh, Bir; Avci, Utku; Eichler Inwood, Sarah E; Grimson, Mark J; Landgraf, Jeff; Mohnen, Debra; Sørensen, Iben; Wilkerson, Curtis G; Willats, William G T; Haigler, Candace H

2009-06-01

Cotton (Gossypium hirsutum) provides the world's dominant renewable textile fiber, and cotton fiber is valued as a research model because of its extensive elongation and secondary wall thickening. Previously, it was assumed that fibers elongated as individual cells. In contrast, observation by cryo-field emission-scanning electron microscopy of cotton fibers developing in situ within the boll demonstrated that fibers elongate within tissue-like bundles. These bundles were entrained by twisting fiber tips and consolidated by adhesion of a cotton fiber middle lamella (CFML). The fiber bundles consolidated via the CFML ultimately formed a packet of fiber around each seed, which helps explain how thousands of cotton fibers achieve their great length within a confined space. The cell wall nature of the CFML was characterized using transmission electron microscopy, including polymer epitope labeling. Toward the end of elongation, up-regulation occurred in gene expression and enzyme activities related to cell wall hydrolysis, and targeted breakdown of the CFML restored fiber individuality. At the same time, losses occurred in certain cell wall polymer epitopes (as revealed by comprehensive microarray polymer profiling) and sugars within noncellulosic matrix components (as revealed by gas chromatography-mass spectrometry analysis of derivatized neutral and acidic glycosyl residues). Broadly, these data show that adhesion modulated by an outer layer of the primary wall can coordinate the extensive growth of a large group of cells and illustrate dynamic changes in primary wall structure and composition occurring during the differentiation of one cell type that spends only part of its life as a tissue.

Modification of the activity of cell wall-bound peroxidase by hypergravity in relation to the stimulation of lignin formation in azuki bean epicotyls

NASA Astrophysics Data System (ADS)

Wakabayashi, Kazuyuki; Nakano, Saho; Soga, Kouichi; Hoson, Takayuki

Lignin is a component of cell walls of terrestrial plants, which provides cell walls with the mechanical rigidity. Lignin is a phenolic polymer with high molecular mass and formed by the polymerization of phenolic substances on a cellulosic matrix. The polymerization is catalyzed by cell wall-bound peroxidase, and thus the activity of this enzyme regulates the rate of formation of lignin. In the present study, the changes in the lignin content and the activity of cell wall peroxidase were investigated along epicotyls of azuki bean seedlings grown under hypergravity conditions. The endogenous growth occurred primarily in the upper regions of the epicotyl and no growth was detected in the middle or basal regions. The amounts of acetyl bromide-soluble lignin increased from the upper to the basal regions of epicotyls. The lignin content per unit length in the basal region was three times higher than that in the upper region. Hypergravity treatment at 300 g for 6 h stimulated the increase in the lignin content in all regions of epicotyls, particularly in the basal regions. The peroxidase activity in the protein fraction extracted from the cell wall preparation with a high ionic strength buffer also increased gradually toward the basal region, and hypergravity treatment clearly increased the activity in all regions. There was a close correlation between the lignin content and the enzyme activity. These results suggest that gravity stimuli modulate the activity of cell wall-bound peroxidase, which, in turn, causes the stimulation of the lignin formation in stem organs.

Cell wall composition throughout development for the model grass Brachypodium distachyon

PubMed Central

Rancour, David M.; Marita, Jane M.; Hatfield, Ronald D.

2012-01-01

Temperate perennial grasses are important worldwide as a livestock nutritive energy source and a potential feedstock for lignocellulosic biofuel production. The annual temperate grass Brachypodium distachyon has been championed as a useful model system to facilitate biological research in agriculturally important temperate forage grasses based on phylogenetic relationships. To physically corroborate genetic predictions, we determined the chemical composition profiles of organ-specific cell walls throughout the development of two common diploid accessions of Brachypodium distachyon, Bd21-3 and Bd21. Chemical analysis was performed on cell walls isolated from distinct organs (i.e., leaves, sheaths, stems, and roots) at three developmental stages of (1) 12-day seedling, (2) vegetative-to-reproductive transition, and (3) mature seed fill. In addition, we have included cell wall analysis of embryonic callus used for genetic transformations. Composition of cell walls based on components lignin, hydroxycinnamates, uronosyls, neutral sugars, and protein suggests that Brachypodium distachyon is similar chemically to agriculturally important forage grasses. There were modest compositional differences in hydroxycinnamate profiles between accessions Bd21-3 and Bd21. In addition, when compared to agronomical important C3 grasses, more mature Brachypodium stem cell walls have a relative increase in glucose of 48% and a decrease in lignin of 36%. Though differences exist between Brachypodium and agronomical important C3 grasses, Brachypodium distachyon should be still a useful model system for genetic manipulation of cell wall composition to determine the impact upon functional characteristics such as rumen digestibility or energy conversion efficiency for bioenergy production. PMID:23227028

The Utilization of Plant Facilities on the International Space Station—The Composition, Growth, and Development of Plant Cell Walls under Microgravity Conditions

PubMed Central

Jost, Ann-Iren Kittang; Hoson, Takayuki; Iversen, Tor-Henning

2015-01-01

In the preparation for missions to Mars, basic knowledge of the mechanisms of growth and development of living plants under microgravity (micro-g) conditions is essential. Focus has centered on the g-effects on rigidity, including mechanisms of signal perception, transduction, and response in gravity resistance. These components of gravity resistance are linked to the evolution and acquisition of responses to various mechanical stresses. An overview is given both on the basic effect of hypergravity as well as of micro-g conditions in the cell wall changes. The review includes plant experiments in the US Space Shuttle and the effect of short space stays (8–14 days) on single cells (plant protoplasts). Regeneration of protoplasts is dependent on cortical microtubules to orient the nascent cellulose microfibrils in the cell wall. The space protoplast experiments demonstrated that the regeneration capacity of protoplasts was retarded. Two critical factors are the basis for longer space experiments: a. the effects of gravity on the molecular mechanisms for cell wall development, b. the availability of facilities and hardware for performing cell wall experiments in space and return of RNA/DNA back to the Earth. Linked to these aspects is a description of existing hardware functioning on the International Space Station. PMID:27135317

The Utilization of Plant Facilities on the International Space Station-The Composition, Growth, and Development of Plant Cell Walls under Microgravity Conditions.

PubMed

Jost, Ann-Iren Kittang; Hoson, Takayuki; Iversen, Tor-Henning

2015-01-20

In the preparation for missions to Mars, basic knowledge of the mechanisms of growth and development of living plants under microgravity (micro-g) conditions is essential. Focus has centered on the g-effects on rigidity, including mechanisms of signal perception, transduction, and response in gravity resistance. These components of gravity resistance are linked to the evolution and acquisition of responses to various mechanical stresses. An overview is given both on the basic effect of hypergravity as well as of micro-g conditions in the cell wall changes. The review includes plant experiments in the US Space Shuttle and the effect of short space stays (8-14 days) on single cells (plant protoplasts). Regeneration of protoplasts is dependent on cortical microtubules to orient the nascent cellulose microfibrils in the cell wall. The space protoplast experiments demonstrated that the regeneration capacity of protoplasts was retarded. Two critical factors are the basis for longer space experiments: a. the effects of gravity on the molecular mechanisms for cell wall development, b. the availability of facilities and hardware for performing cell wall experiments in space and return of RNA/DNA back to the Earth. Linked to these aspects is a description of existing hardware functioning on the International Space Station.

Immunolocalization of pectic polysaccharides during abscission in pea seeds (Pisum sativum L.) and in abscission less def pea mutant seeds.

PubMed

Lee, YeonKyeong; Ayeh, Kwadwo Owusu; Ambrose, Mike; Hvoslef-Eide, Anne Kathrine

2016-08-31

In pea seeds (Pisum sativum L.), the presence of the Def locus determines abscission event between its funicle and the seed coat. Cell wall remodeling is a necessary condition for abscission of pea seed. The changes in cell wall components in wild type (WT) pea seed with Def loci showing seed abscission and in abscission less def mutant peas were studied to identify the factors determining abscission and non-abscission event. Changes in pectic polysaccharides components were investigated in WT and def mutant pea seeds using immunolabeling techniques. Pectic monoclonal antibodies (1 → 4)-β-D-galactan (LM5), (1 → 5)-α-L-arabinan(LM6), partially de-methyl esterified homogalacturonan (HG) (JIM5) and methyl esterified HG (JIM7) were used for this study. Prior to abscission zone (AZ) development, galactan and arabinan reduced in the predestined AZ of the pea seed and disappeared during the abscission process. The AZ cells had partially de-methyl esterified HG while other areas had highly methyl esterified HG. A strong JIM5 labeling in the def mutant may be related to cell wall rigidity in the mature def mutants. In addition, the appearance of pectic epitopes in two F3 populations resulting from cross between WT and def mutant parents was studied. As a result, we identified that homozygous dominant lines (Def/Def) showing abscission and homozygous recessive lines (def/def) showing non-abscission had similar immunolabeling pattern to their parents. However, the heterogeneous lines (Def/def) showed various immunolabeling pattern and the segregation pattern of the Def locus. Through the study of the complexity and variability of pectins in plant cell walls as well as understanding the segregation patterns of the Def locus using immunolabeling techniques, we conclude that cell wall remodeling occurs in the abscission process and de-methyl esterification may play a role in the non-abscission event in def mutant. Overall, this study contributes new insights into understanding the structural and architectural organization of the cell walls during abscission.

Modification of the nanostructure of lignocellulose cell walls via a non-enzymatic lignocellulose deconstruction system in brown rot wood-decay fungi.

PubMed

Goodell, Barry; Zhu, Yuan; Kim, Seong; Kafle, Kabindra; Eastwood, Daniel; Daniel, Geoffrey; Jellison, Jody; Yoshida, Makoto; Groom, Leslie; Pingali, Sai Venkatesh; O'Neill, Hugh

2017-01-01

Wood decayed by brown rot fungi and wood treated with the chelator-mediated Fenton (CMF) reaction, either alone or together with a cellulose enzyme cocktail, was analyzed by small angle neutron scattering (SANS), sum frequency generation (SFG) spectroscopy, Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), atomic force microscopy (AFM), and transmission electron microscopy (TEM). Results showed that the CMF mechanism mimicked brown rot fungal attack for both holocellulose and lignin components of the wood. Crystalline cellulose and lignin were both depolymerized by the CMF reaction. Porosity of the softwood cell wall did not increase during CMF treatment, enzymes secreted by the fungi did not penetrate the decayed wood. The enzymes in the cellulose cocktail also did not appear to alter the effects of the CMF-treated wood relative to enhancing cell wall deconstruction. This suggests a rethinking of current brown rot decay models and supports a model where monomeric sugars and oligosaccharides diffuse from the softwood cell walls during non-enzymatic action. In this regard, the CMF mechanism should not be thought of as a "pretreatment" used to permit enzymatic penetration into softwood cell walls, but instead it enhances polysaccharide components diffusing to fungal enzymes located in wood cell lumen environments during decay. SANS and other data are consistent with a model for repolymerization and aggregation of at least some portion of the lignin within the cell wall, and this is supported by AFM and TEM data. The data suggest that new approaches for conversion of wood substrates to platform chemicals in biorefineries could be achieved using the CMF mechanism with >75% solubilization of lignocellulose, but that a more selective suite of enzymes and other downstream treatments may be required to work when using CMF deconstruction technology. Strategies to enhance polysaccharide release from lignocellulose substrates for enhanced enzymatic action and fermentation of the released fraction would also aid in the efficient recovery of the more uniform modified lignin fraction that the CMF reaction generates to enhance biorefinery profitability.

Identification and Characterization of Cell Wall Proteins of a Toxic Dinoflagellate Alexandrium catenella Using 2-D DIGE and MALDI TOF-TOF Mass Spectrometry

PubMed Central

Wang, Da-Zhi; Dong, Hong-Po; Li, Cheng; Xie, Zhang-Xian; Lin, Lin; Hong, Hua-Sheng

2011-01-01

The cell wall is an important subcellular component of dinoflagellate cells with regard to various aspects of cell surface-associated ecophysiology, but the full range of cell wall proteins (CWPs) and their functions remain to be elucidated. This study identified and characterized CWPs of a toxic dinoflagellate, Alexandrium catenella, using a combination of 2D fluorescence difference gel electrophoresis (DIGE) and MALDI TOF-TOF mass spectrometry approaches. Using sequential extraction and temperature shock methods, sequentially extracted CWPs and protoplast proteins, respectively, were separated from A. catenella. From the comparison between sequentially extracted CWPs labeled with Cy3 and protoplast proteins labeled with Cy5, 120 CWPs were confidently identified in the 2D DIGE gel. These proteins gave positive identification of protein orthologues in the protein database using de novo sequence analysis and homology-based search. The majority of the prominent CWPs identified were hypothetical or putative proteins with unknown function or no annotation, while cell wall modification enzymes, cell wall structural proteins, transporter/binding proteins, and signaling and defense proteins were tentatively identified in agreement with the expected role of the extracellular matrix in cell physiology. This work represents the first attempt to investigate dinoflagellate CWPs and provides a potential tool for future comprehensive characterization of dinoflagellate CWPs and elucidation of their physiological functions. PMID:21904561

Pathobiology of Pneumocystis pneumonia: life cycle, cell wall and cell signal transduction.

PubMed

Skalski, Joseph H; Kottom, Theodore J; Limper, Andrew H

2015-09-01

Pneumocystis is a genus of ascomycetous fungi that are highly morbid pathogens in immunosuppressed humans and other mammals. Pneumocystis cannot easily be propagated in culture, which has greatly hindered understanding of its pathobiology. The Pneumocystis life cycle is intimately associated with its mammalian host lung environment, and life cycle progression is dependent on complex interactions with host alveolar epithelial cells and the extracellular matrix. The Pneumocystis cell wall is a varied and dynamic structure containing a dominant major surface glycoprotein, β-glucans and chitins that are important for evasion of host defenses and stimulation of the host immune system. Understanding of Pneumocystis cell signaling pathways is incomplete, but much has been deduced by comparison of the Pneumocystis genome with homologous genes and proteins in related fungi. In this mini-review, the pathobiology of Pneumocystis is reviewed, with particular focus on the life cycle, cell wall components and cell signal transduction. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Streptomycetes in house dust: associations with housing characteristics and endotoxin

EPA Science Inventory

In addition to mold, indoor bioaerosols also contain bacterial components that may have implications for human health. Endotoxin is a cell wall component in Gram-negative bacteria present at varying levels indoors that has been found to have respiratory health implications. Stre...

G-fibre cell wall development in willow stems during tension wood induction

PubMed Central

Gritsch, Cristina; Wan, Yongfang; Mitchell, Rowan A. C.; Shewry, Peter R.; Hanley, Steven J.; Karp, Angela

2015-01-01

Willows (Salix spp.) are important as a potential feedstock for bioenergy and biofuels. Previous work suggested that reaction wood (RW) formation could be a desirable trait for biofuel production in willows as it is associated with increased glucose yields, but willow RW has not been characterized for cell wall components. Fasciclin-like arabinogalactan (FLA) proteins are highly up-regulated in RW of poplars and are considered to be involved in cell adhesion and cellulose biosynthesis. COBRA genes are involved in anisotropic cell expansion by modulating the orientation of cellulose microfibril deposition. This study determined the temporal and spatial deposition of non-cellulosic polysaccharides in cell walls of the tension wood (TW) component of willow RW and compared it with opposite wood (OW) and normal wood (NW) using specific antibodies and confocal laser scanning microscopy and transmission electron microscopy. In addition, the expression patterns of an FLA gene (SxFLA12) and a COBRA-like gene (SxCOBL4) were compared using RNA in situ hybridization. Deposition of the non-cellulosic polysaccharides (1–4)-β-D-galactan, mannan and de-esterified homogalacturonan was found to be highly associated with TW, often with the G-layer itself. Of particular interest was that the G-layer itself can be highly enriched in (1–4)-β-D-galactan, especially in G-fibres where the G-layer is still thickening, which contrasts with previous studies in poplar. Only xylan showed a similar distribution in TW, OW, and NW, being restricted to the secondary cell wall layers. SxFLA12 and SxCOBL4 transcripts were specifically expressed in developing TW, confirming their importance. A model of polysaccharides distribution in developing willow G-fibre cells is presented. PMID:26220085

Transfer cell wall ingrowths and vein loading characteristics in pea leaf discs. [Pisum sativum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wimmers, L.E.; Turgeon, R.

1987-04-01

Transfer cell wall ingrowths are thought to increase transport capacity by increasing plasmalemma surface area. Leaf minor vein phloem transfer cells presumably enhance phloem loading. In Pisum sativum cv. Little marvel grown under different light regimes (150 to 1000 ..mu..mol photons m/sup -2/ sec/sup -1/) there is a positive correlation between light intensity and wall ingrowth area in phloem transfer cells. The extent of ingrowth and correlation to light intensity is greatest in minor veins, decreasing as vein size increases. Vein loading was assayed by floating abraded leaf discs on /sup 14/C-sucrose (10 mM). There is a positive correlation betweenmore » uptake and transfer cell wall area, although the latter increased more than the former. The difference in uptake is stable throughout the photoperiod, and is also stable in mature leaves for at least four days after plants are transfered to a different light intensity. Sucrose uptake is biphasic. The saturable component of uptake is sensitive to light intensity, the Km for sucrose is negatively correlated to light intensity, while V/sub max/remains unchanged.« less

Changes of myoid and endothelial cells in the peritubular wall during contraction of the seminiferous tubule.

PubMed

Losinno, Antonella D; Sorrivas, Viviana; Ezquer, Marcelo; Ezquer, Fernando; López, Luis A; Morales, Alfonsina

2016-08-01

The wall of the seminiferous tubule in rodents consists of an inner layer of myoid cells covered by an outer layer of endothelial cells. Myoid cells are a type of smooth muscle cell containing α-actin filaments arranged in two independent layers that contract when stimulated by endothelin-1. The irregular surface relief of the tubular wall is often considered a hallmark of contraction induced by a variety of stimuli. We examine morphological changes of the rat seminiferous tubule wall during contraction by a combination of light, confocal, transmission and scanning electron microscopy. During ET-1-induced contraction, myoid cells changed from a flat to a conical shape, but their actin filaments remained in independent layers. As a consequence of myoid cell contraction, the basement membrane became wavy, orientation of collagen fibers in the extracellular matrix was altered and the endothelial cell layer became folded. To observe the basement of the myoid cell cone, the endothelial cell monolayer was removed by collagenase digestion prior to SEM study. In contracted tubules, it is possible to distinguish cell relief: myoid cells have large folds on the external surface oriented parallel to the tubular axis, whereas endothelial cells have numerous cytoplasmic projections facing the interstitium. The myoid cell cytoskeleton is unusual in that the actin filaments are arranged in two orthogonal layers, which adopt differing shapes during contraction with myoid cells becoming cone-shaped. This arrangement impacts on other components of the seminiferous tubule wall and affects the propulsion of the tubular contents to the rete testis.

Functional Analysis of the Cytoskeleton Protein MreB from Chlamydophila pneumoniae

PubMed Central

Gaballah, Ahmed; Kloeckner, Anna; Otten, Christian; Sahl, Hans-Georg; Henrichfreise, Beate

2011-01-01

In rod-shaped bacteria, the bacterial actin ortholog MreB is considered to organize the incorporation of cell wall precursors into the side-wall, whereas the tubulin homologue FtsZ is known to tether incorporation of cell wall building blocks at the developing septum. For intracellular bacteria, there is no need to compensate osmotic pressure by means of a cell wall, and peptidoglycan has not been reliably detected in Chlamydiaceae. Surprisingly, a nearly complete pathway for the biosynthesis of the cell wall building block lipid II has been found in the genomes of Chlamydiaceae. In a previous study, we discussed the hypothesis that conservation of lipid II biosynthesis in cell wall-lacking bacteria may reflect the intimate molecular linkage of cell wall biosynthesis and cell division and thus an essential role of the precursor in cell division. Here, we investigate why spherical-shaped chlamydiae harbor MreB which is almost exclusively found in elongated bacteria (i.e. rods, vibrios, spirilla) whereas they lack the otherwise essential division protein FtsZ. We demonstrate that chlamydial MreB polymerizes in vitro and that polymerization is not inhibited by the blocking agent A22. As observed for MreB from Bacillus subtilis, chlamydial MreB does not require ATP for polymerization but is capable of ATP hydrolysis in phosphate release assays. Co-pelleting and bacterial two-hybrid experiments indicate that MreB from Chlamydophila (Chlamydia) pneumoniae interacts with MurF, MraY and MurG, three key components in lipid II biosynthesis. In addition, MreB polymerization is improved in the presence of MurF. Our findings suggest that MreB is involved in tethering biosynthesis of lipid II and as such may be necessary for maintaining a functional divisome machinery in Chlamydiaceae. PMID:22022378

Functional analysis of the cytoskeleton protein MreB from Chlamydophila pneumoniae.

PubMed

Gaballah, Ahmed; Kloeckner, Anna; Otten, Christian; Sahl, Hans-Georg; Henrichfreise, Beate

2011-01-01

In rod-shaped bacteria, the bacterial actin ortholog MreB is considered to organize the incorporation of cell wall precursors into the side-wall, whereas the tubulin homologue FtsZ is known to tether incorporation of cell wall building blocks at the developing septum. For intracellular bacteria, there is no need to compensate osmotic pressure by means of a cell wall, and peptidoglycan has not been reliably detected in Chlamydiaceae. Surprisingly, a nearly complete pathway for the biosynthesis of the cell wall building block lipid II has been found in the genomes of Chlamydiaceae. In a previous study, we discussed the hypothesis that conservation of lipid II biosynthesis in cell wall-lacking bacteria may reflect the intimate molecular linkage of cell wall biosynthesis and cell division and thus an essential role of the precursor in cell division. Here, we investigate why spherical-shaped chlamydiae harbor MreB which is almost exclusively found in elongated bacteria (i.e. rods, vibrios, spirilla) whereas they lack the otherwise essential division protein FtsZ. We demonstrate that chlamydial MreB polymerizes in vitro and that polymerization is not inhibited by the blocking agent A22. As observed for MreB from Bacillus subtilis, chlamydial MreB does not require ATP for polymerization but is capable of ATP hydrolysis in phosphate release assays. Co-pelleting and bacterial two-hybrid experiments indicate that MreB from Chlamydophila (Chlamydia) pneumoniae interacts with MurF, MraY and MurG, three key components in lipid II biosynthesis. In addition, MreB polymerization is improved in the presence of MurF. Our findings suggest that MreB is involved in tethering biosynthesis of lipid II and as such may be necessary for maintaining a functional divisome machinery in Chlamydiaceae.

Examining an underappreciated control on lignin decomposition in soils? Effects of reactive manganese species on intact plant cell walls

NASA Astrophysics Data System (ADS)

Keiluweit, M.; Bougoure, J.; Pett-Ridge, J.; Kleber, M.; Nico, P. S.

2011-12-01

Lignin comprises a dominant proportion of carbon fluxes into the soil (representing up to 50% of plant litter and roots). Two lines of evidence suggest that manganese (Mn) acts as a strong controlling factor on the residence time of lignin in soil ecosystems. First, Mn content is highly correlated with litter decomposition in temperate and boreal forest soil ecosystems and, second, microbial agents of lignin degradation have been reported to rely on reactive Mn(III)-complexes to specifically oxidize lignin. However, few attempts have been made to isolate the mechanisms responsible for the apparent Mn-dependence of lignin decomposition in soils. Here we tested the hypothesis that Mn(III)-oxalate complexes may act as a perforating 'pretreatment' for structurally intact plant cell walls. We propose that these diffusible oxidizers are small enough to penetrate and react with non-porous ligno-cellulose in cell walls. This process was investigated by reacting single Zinnia elegans tracheary elements with Mn(III)-oxalate complexes in a continuous flow-through microreactor. The uniformity of cultured tracheary elements allowed us to examine Mn(III)-induced changes in cell wall chemistry and ultrastructure on the micro-scale using fluorescence and electron microscopy as well as synchrotron-based infrared and X-ray spectromicroscopy. Our results show that Mn(III)-complexes substantially oxidize specific lignin components of the cell wall, solubilize decomposition products, severely undermine the cell wall integrity, and cause cell lysis. We conclude that Mn(III)-complexes induce oxidative damage in plant cell walls that renders ligno-cellulose substrates more accessible for microbial lignin- and cellulose-decomposing enzymes. Implications of our results for the rate limiting impact of soil Mn speciation and availability on litter decomposition in forest soils will be discussed.

Imaging Cell Wall Architecture in Single Zinnia elegans Tracheary Elements1[OA

PubMed Central

Lacayo, Catherine I.; Malkin, Alexander J.; Holman, Hoi-Ying N.; Chen, Liang; Ding, Shi-You; Hwang, Mona S.; Thelen, Michael P.

2010-01-01

The chemical and structural organization of the plant cell wall was examined in Zinnia elegans tracheary elements (TEs), which specialize by developing prominent secondary wall thickenings underlying the primary wall during xylogenesis in vitro. Three imaging platforms were used in conjunction with chemical extraction of wall components to investigate the composition and structure of single Zinnia TEs. Using fluorescence microscopy with a green fluorescent protein-tagged Clostridium thermocellum family 3 carbohydrate-binding module specific for crystalline cellulose, we found that cellulose accessibility and binding in TEs increased significantly following an acidified chlorite treatment. Examination of chemical composition by synchrotron radiation-based Fourier-transform infrared spectromicroscopy indicated a loss of lignin and a modest loss of other polysaccharides in treated TEs. Atomic force microscopy was used to extensively characterize the topography of cell wall surfaces in TEs, revealing an outer granular matrix covering the underlying meshwork of cellulose fibrils. The internal organization of TEs was determined using secondary wall fragments generated by sonication. Atomic force microscopy revealed that the resulting rings, spirals, and reticulate structures were composed of fibrils arranged in parallel. Based on these combined results, we generated an architectural model of Zinnia TEs composed of three layers: an outermost granular layer, a middle primary wall composed of a meshwork of cellulose fibrils, and inner secondary wall thickenings containing parallel cellulose fibrils. In addition to insights in plant biology, studies using Zinnia TEs could prove especially productive in assessing cell wall responses to enzymatic and microbial degradation, thus aiding current efforts in lignocellulosic biofuel production. PMID:20592039

Hormonal and gravitropic specificity in the regulation of growth and cell wall synthesis in pulvini and internodes from shoots of Avena sativa L. (oat).

PubMed Central

Montague, M J

1995-01-01

Segments can be cut from the peduncular-1 internode of oat (Avena sativa L.) shoots so as to contain the graviresponsive leaf-sheath pulvinus and gibberellin-sensitive internodal tissue. Incorporation of [14C]glucose was used to monitor cell wall synthesis in these two tissues as affected by gravistimulus, indoleacetic acid (IAA), gibberellic acid (GA3), and fusicoccin (FC). Pulvinar cell wall synthesis was promoted by IAA and FC (both within about 1 h), as well as by gravistimulus (starting between 3 and 6 h), whereas GA3 had no effect on nongravistimulated pulvini. In contrast, GA3 and FC promoted internodal cell wall synthesis (initiated between 1 and 2 h), whereas IAA and gravistimulus caused a decrease in internodal uptake. FC preferentially promoted incorporation into the matrix component of the wall in both tissues. Gravistimulus failed to increase responsiveness of pulvinar tissue to IAA, whereas GA3 partially overcame gravistimulus-promoted incorporation into pulvinar cell wall, probably because of preferential movement of label into the rapidly elongating internode. The results demonstrate that these eight stimulus/tissue combinations can be examined easily in an isolated 10-mm stem segment, providing new opportunities for the comparative study of tissue- and stimulus-specific events in gene regulation and signal transduction in agronomically important cereals. PMID:11536686

Super-resolution microscopy reveals cell wall dynamics and peptidoglycan architecture in ovococcal bacteria.

PubMed

Wheeler, Richard; Mesnage, Stéphane; Boneca, Ivo G; Hobbs, Jamie K; Foster, Simon J

2011-12-01

Cell morphology and viability in Eubacteria is dictated by the architecture of peptidoglycan, the major and essential structural component of the cell wall. Although the biochemical composition of peptidoglycan is well understood, how the peptidoglycan architecture can accommodate the dynamics of growth and division while maintaining cell shape remains largely unknown. Here, we elucidate the peptidoglycan architecture and dynamics of bacteria with ovoid cell shape (ovococci), which includes a number of important pathogens, by combining biochemical analyses with atomic force and super-resolution microscopies. Atomic force microscopy analysis showed preferential orientation of the peptidoglycan network parallel to the short axis of the cell, with distinct architectural features associated with septal and peripheral wall synthesis. Super-resolution three-dimensional structured illumination fluorescence microscopy was applied for the first time in bacteria to unravel the dynamics of peptidoglycan assembly in ovococci. The ovococci have a unique peptidoglycan architecture and growth mode not observed in other model organisms. © 2011 Blackwell Publishing Ltd.

Building bridges: formin1 of Arabidopsis forms a connection between the cell wall and the actin cytoskeleton.

PubMed

Martinière, Alexandre; Gayral, Philippe; Hawes, Chris; Runions, John

2011-04-01

Actin microfilament (MF) organization and remodelling is critical to cell function. The formin family of actin binding proteins are involved in nucleating MFs in Arabidopsis thaliana. They all contain formin homology domains in the intracellular, C-terminal half of the protein that interacts with MFs. Formins in class I are usually targeted to the plasma membrane and this is true of Formin1 (AtFH1) of A. thaliana. In this study, we have investigated the extracellular domain of AtFH1 and we demonstrate that AtFH1 forms a bridge from the actin cytoskeleton, across the plasma membrane and is anchored within the cell wall. AtFH1 has a large, extracellular domain that is maintained by purifying selection and that contains four conserved regions, one of which is responsible for immobilising the protein. Protein anchoring within the cell wall is reduced in constructs that express truncations of the extracellular domain and in experiments in protoplasts without primary cell walls. The 18 amino acid proline-rich extracellular domain that is responsible for AtFH1 anchoring has homology with cell-wall extensins. We also have shown that anchoring of AtFH1 in the cell wall promotes actin bundling within the cell and that overexpression of AtFH1 has an inhibitory effect on organelle actin-dependant dynamics. Thus, the AtFH1 bridge provides stable anchor points for the actin cytoskeleton and is probably a crucial component of the signalling response and actin-remodelling mechanisms. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Transient alkalinization of the leaf apoplast stiffens the cell wall during onset of chloride salinity in corn leaves.

PubMed

Geilfus, Christoph-Martin; Tenhaken, Raimund; Carpentier, Sebastien Christian

2017-11-17

During chloride salinity, the pH of the leaf apoplast (pH apo ) transiently alkalizes. There is an ongoing debate about the physiological relevance of these stress-induced pH apo changes. Using proteomic analyses of expanding leaves of corn ( Zea mays L.), we show that this transition in pH apo conveys functionality by (i) adjusting protein abundances and (ii) affecting the rheological properties of the cell wall. pH apo was monitored in planta via microscopy-based ratio imaging, and the leaf-proteomic response to the transient leaf apoplastic alkalinization was analyzed via ultra-high performance liquid chromatography-MS. This analysis identified 1459 proteins, of which 44 exhibited increased abundance specifically through the chloride-induced transient rise in pH apo These elevated protein abundances did not directly arise from high tissue concentrations of Cl - or Na + but were due to changes in the pH apo Most of these proteins functioned in growth-relevant processes and in the synthesis of cell wall-building components such as arabinose. Measurements with a linear-variable differential transducer revealed that the transient alkalinization rigidified ( i.e. stiffened) the cell wall during the onset of chloride salinity. A decrease in t -coumaric and t -ferulic acids indicates that the wall stiffening arises from cross-linkage to cell wall polymers. We conclude that the pH of the apoplast represents a dynamic factor that is mechanistically coupled to cellular responses to chloride stress. By hardening the wall, the increased pH abrogates wall loosening required for cell expansion and growth. We conclude that the transient alkalinization of the leaf apoplast is related to salinity-induced growth reduction. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Isolation of plasmodesmata from Arabidopsis suspension culture cells.

PubMed

Grison, Magali S; Fernandez-Calvino, Lourdes; Mongrand, Sébastien; Bayer, Emmanuelle M F

2015-01-01

Due to their position firmly anchored within the plant cell wall, plasmodesmata (PD) are notoriously difficult to isolate from plant tissue. Yet, getting access to isolated PD represents the most straightforward strategy for the identification of their molecular components. Proteomic and lipidomic analyses of such PD fractions have provided and will continue to provide critical information on the functional and structural elements that define these membranous nano-pores. Here, we describe a two-step simple purification procedure that allows isolation of pure PD-derived membranes from Arabidopsis suspension cells. The first step of this procedure consists in isolating cell wall fragments containing intact PD while free of contamination from other cellular compartments. The second step relies on an enzymatic degradation of the wall matrix and the subsequent release of "free" PD. Isolated PD membranes provide a suitable starting material for the analysis of PD-associated proteins and lipids.

Stimulation of complement component C3 synthesis in macrophagelike cell lines by group B streptococci.

PubMed Central

Goodrum, K J

1987-01-01

Complement levels and complement activation are key determinants in streptococcus-induced inflammatory responses. Activation of macrophage functions, such as complement synthesis, by group B streptococci (GBS) was examined as a possible component of GBS-induced chronic inflammation. Using an enzyme-linked immunosorbent assay, secreted C3 from mouse macrophagelike cell lines (PU5-1.8 and J774A.1) was monitored after cultivation with GBS. Whole, heat-killed GBS (1 to 10 CFU per macrophage) of both type Ia and III strains induced 25 to 300% increases in secreted C3 in both cell lines after a 24-h cultivation. GBS-treated cell lines exhibited increases in secreted lysozyme (10%) and in cellular protein (25 to 50%). Inhibition of macrophage phagocytosis by cytochalasin B inhibited GBS stimulation of C3. Purified cell walls of GBS type III strain 603-79 (1 to 10 micrograms/ml) also enhanced C3 synthesis. Local enhancement of macrophage C3 production by ingested streptococci or by persistent cell wall antigens may serve to promote chronic inflammatory responses. PMID:3552987

Systems and synthetic biology approaches to alter plant cell walls and reduce biomass recalcitrance.

PubMed

Kalluri, Udaya C; Yin, Hengfu; Yang, Xiaohan; Davison, Brian H

2014-12-01

Fine-tuning plant cell wall properties to render plant biomass more amenable to biofuel conversion is a colossal challenge. A deep knowledge of the biosynthesis and regulation of plant cell wall and a high-precision genome engineering toolset are the two essential pillars of efforts to alter plant cell walls and reduce biomass recalcitrance. The past decade has seen a meteoric rise in use of transcriptomics and high-resolution imaging methods resulting in fresh insights into composition, structure, formation and deconstruction of plant cell walls. Subsequent gene manipulation approaches, however, commonly include ubiquitous mis-expression of a single candidate gene in a host that carries an intact copy of the native gene. The challenges posed by pleiotropic and unintended changes resulting from such an approach are moving the field towards synthetic biology approaches. Synthetic biology builds on a systems biology knowledge base and leverages high-precision tools for high-throughput assembly of multigene constructs and pathways, precision genome editing and site-specific gene stacking, silencing and/or removal. Here, we summarize the recent breakthroughs in biosynthesis and remodelling of major secondary cell wall components, assess the impediments in obtaining a systems-level understanding and explore the potential opportunities in leveraging synthetic biology approaches to reduce biomass recalcitrance. Published 2014. This article is a U.S. Government work and is in the public domain in the USA. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Cardiac conduction system

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... cardiac muscle cells in the walls of the heart that send signals to the heart muscle causing it to contract. The main components ... the cardiac conduction system's electrical activity in the heart.

SND2, a NAC transcription factor gene, regulates genes involved in secondary cell wall development in Arabidopsis fibres and increases fibre cell area in Eucalyptus

PubMed Central

2011-01-01

Background NAC domain transcription factors initiate secondary cell wall biosynthesis in Arabidopsis fibres and vessels by activating numerous transcriptional regulators and biosynthetic genes. NAC family member SND2 is an indirect target of a principal regulator of fibre secondary cell wall formation, SND1. A previous study showed that overexpression of SND2 produced a fibre cell-specific increase in secondary cell wall thickness in Arabidopsis stems, and that the protein was able to transactivate the cellulose synthase8 (CesA8) promoter. However, the full repertoire of genes regulated by SND2 is unknown, and the effect of its overexpression on cell wall chemistry remains unexplored. Results We overexpressed SND2 in Arabidopsis and analyzed homozygous lines with regards to stem chemistry, biomass and fibre secondary cell wall thickness. A line showing upregulation of CesA8 was selected for transcriptome-wide gene expression profiling. We found evidence for upregulation of biosynthetic genes associated with cellulose, xylan, mannan and lignin polymerization in this line, in agreement with significant co-expression of these genes with native SND2 transcripts according to public microarray repositories. Only minor alterations in cell wall chemistry were detected. Transcription factor MYB103, in addition to SND1, was upregulated in SND2-overexpressing plants, and we detected upregulation of genes encoding components of a signal transduction machinery recently proposed to initiate secondary cell wall formation. Several homozygous T4 and hemizygous T1 transgenic lines with pronounced SND2 overexpression levels revealed a negative impact on fibre wall deposition, which may be indirectly attributable to excessive overexpression rather than co-suppression. Conversely, overexpression of SND2 in Eucalyptus stems led to increased fibre cross-sectional cell area. Conclusions This study supports a function for SND2 in the regulation of cellulose and hemicellulose biosynthetic genes in addition of those involved in lignin polymerization and signalling. SND2 seems to occupy a subordinate but central tier in the secondary cell wall transcriptional network. Our results reveal phenotypic differences in the effect of SND2 overexpression between woody and herbaceous stems and emphasize the importance of expression thresholds in transcription factor studies. PMID:22133261

Cell wall peptidoglycan architecture in Bacillus subtilis

PubMed Central

Hayhurst, Emma J.; Kailas, Lekshmi; Hobbs, Jamie K.; Foster, Simon J.

2008-01-01

The bacterial cell wall is essential for viability and shape determination. Cell wall structural dynamics allowing growth and division, while maintaining integrity is a basic problem governing the life of bacteria. The polymer peptidoglycan is the main structural component for most bacteria and is made up of glycan strands that are cross-linked by peptide side chains. Despite study and speculation over many years, peptidoglycan architecture has remained largely elusive. Here, we show that the model rod-shaped bacterium Bacillus subtilis has glycan strands up to 5 μm, longer than the cell itself and 50 times longer than previously proposed. Atomic force microscopy revealed the glycan strands to be part of a peptidoglycan architecture allowing cell growth and division. The inner surface of the cell wall has a regular macrostructure with ≈50 nm-wide peptidoglycan cables [average 53 ± 12 nm (n = 91)] running basically across the short axis of the cell. Cross striations with an average periodicity of 25 ± 9 nm (n = 96) along each cable are also present. The fundamental cabling architecture is also maintained during septal development as part of cell division. We propose a coiled-coil model for peptidoglycan architecture encompassing our data and recent evidence concerning the biosynthetic machinery for this essential polymer. PMID:18784364

Pectin Metabolism and Assembly in the Cell Wall of the Charophyte Green Alga Penium margaritaceum1[W][OPEN

PubMed Central

Domozych, David S.; Sørensen, Iben; Popper, Zoë A.; Ochs, Julie; Andreas, Amanda; Fangel, Jonatan U.; Pielach, Anna; Sacks, Carly; Brechka, Hannah; Ruisi-Besares, Pia; Willats, William G.T.; Rose, Jocelyn K.C.

2014-01-01

The pectin polymer homogalacturonan (HG) is a major component of land plant cell walls and is especially abundant in the middle lamella. Current models suggest that HG is deposited into the wall as a highly methylesterified polymer, demethylesterified by pectin methylesterase enzymes and cross-linked by calcium ions to form a gel. However, this idea is based largely on indirect evidence and in vitro studies. We took advantage of the wall architecture of the unicellular alga Penium margaritaceum, which forms an elaborate calcium cross-linked HG-rich lattice on its cell surface, to test this model and other aspects of pectin dynamics. Studies of live cells and microscopic imaging of wall domains confirmed that the degree of methylesterification and sufficient levels of calcium are critical for lattice formation in vivo. Pectinase treatments of live cells and immunological studies suggested the presence of another class of pectin polymer, rhamnogalacturonan I, and indicated its colocalization and structural association with HG. Carbohydrate microarray analysis of the walls of P. margaritaceum, Physcomitrella patens, and Arabidopsis (Arabidopsis thaliana) further suggested the conservation of pectin organization and interpolymer associations in the walls of green plants. The individual constituent HG polymers also have a similar size and branched structure to those of embryophytes. The HG-rich lattice of P. margaritaceum, a member of the charophyte green algae, the immediate ancestors of land plants, was shown to be important for cell adhesion. Therefore, the calcium-HG gel at the cell surface may represent an early evolutionary innovation that paved the way for an adhesive middle lamella in multicellular land plants. PMID:24652345

Probing the effect of polymer molecular weight on penetration into the wood cell wall using polyethylenimine (PEI) as a model compound.

PubMed

Dorvel, Brian; Boopalachandran, Praveenkumar; Chen, Ida; Bowling, Andrew; Williams, Kerry; King, Steve

2018-05-01

Decking is one of the largest applications for the treated wood market. The most challenging property to obtain for treated wood is dimensional stability, which can be achieved, in part, by cell wall bulking, cell wall polymer crosslinking and removal of hygroscopic components in the cell wall. A commonly accepted key requirement is for the actives to infuse through the cell wall, which has a microporosity of ∼5-13 nm. Equally as challenging is being able to measure and quantify the cell wall penetration. Branched polyethylenimine (PEI) was studied as a model polymer for penetration due to its water solubility, polarity, variable molecular weight ranges, and ability to form a chelation complex with preservative metals to treat lumbers. Two different molecular weight polyethylenimines (PEI), one with a weight average molecular weight (Mw) equal to 800 Da and the other 750 000 Da, were investigated for penetration by microscopy and spectroscopy techniques. Analytical methods were developed to both create smooth interfaces and for relative quantitation and visualisation of PEI penetration into the wood. The results showed both PEI with Mw of 800 Da and PEI with Mw of 750 000 Da coated the lumens in high density. However, only the PEI with Mw of 800 appeared to penetrate the cell walls in sufficient levels. Literature has shown the hydrodynamic radii of PEI 750 000 is near 29 nm, whereas a smaller PEI at 25 K showed 4.5 nm. Most importantly the results, based on methods developed, show how molecular weight and tertiary structure of the polymer can affect its penetration, with the microporosity of the wood being the main barrier. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

Novel insights of ethylene role in strawberry cell wall metabolism.

PubMed

Villarreal, Natalia M; Marina, María; Nardi, Cristina F; Civello, Pedro M; Martínez, Gustavo A

2016-11-01

Due to its organoleptic and nutraceutical qualities, strawberry fruit (Fragaria x ananassa, Duch) is a worldwide important commodity. The role of ethylene in the regulation of strawberry cell wall metabolism was studied in fruit from Toyonoka cultivar harvested at white stage, when most changes associated with fruit ripening have begun. Fruit were treated with ethephon, an ethylene-releasing reagent, or with 1-methylcyclopropene (1-MCP), a competitive inhibitor of ethylene action, maintaining a set of non-treated fruit as controls for each condition. Ethephon treated-fruit showed higher contents of hemicelluloses, cellulose and neutral sugars regarding controls, while 1-MCP-treated fruit showed a lower amount of those fractions. On the other hand, ethephon-treated fruit presented a lower quantity of galacturonic acid from ionically and covalently bound pectins regarding controls, while 1-MCP-treated fruit showed higher contents of those components. We also explored the ethylene effect over the mRNA accumulation of genes related to pectins and hemicelluloses metabolism, and a relationship between gene expression patterns and cell wall polysaccharides contents was shown. Moreover, we detected that strawberry necrotrophic pathogens growth more easily on plates containing cell walls from ethephon-treated fruit regarding controls, while a lower growth rate was observed when cell walls from 1-MCP treated fruit were used as the only carbon source, suggesting an effect of ethylene on cell wall structure. Around 60% of strawberry cell wall is made up of pectins, which in turns is 70% made by homogalacturonans. Our findings support the idea of a central role for pectins on strawberry fruit softening and a participation of ethylene in the regulation of this process. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Emodin is identified as the active component of ether extracts from Rhizoma Polygoni Cuspidati, for anti-MRSA activity.

PubMed

Cao, Feng; Peng, Wei; Li, Xiaoli; Liu, Ming; Li, Bin; Qin, Rongxin; Jiang, Weiwei; Cen, Yanyan; Pan, Xichun; Yan, Zifei; Xiao, Kangkang; Zhou, Hong

2015-06-01

This study investigated the anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity and chemical compositions of ether extracts from Rhizoma Polygoni Cuspidati (ET-RPC). Significant anti-MRSA activities of ET-RPC against MRSA252 and MRSA clinical strains were tested in in vitro antibacterial experiments, such as inhibition zone diameter test, minimal inhibitory concentration test, and dynamic bacterial growth assay. Subsequently, 7 major compounds of ET-RPC were purified and identified as polydatin, resveratrol-4-O-d-(6'-galloyl)-glucopyranoside, resveratrol, torachryson-8-O-glucoside, emodin-8-O-glucoside, 6-hydroxy-emodin, and emodin using liquid chromatography - electrospray ionization - tandem mass spectrometry. After investigation of anti-MRSA activities of the 7 major compounds, only emodin had significant anti-MRSA activity. Further, transmission electron microscopy was used to observe morphological changes in the cell wall of MRSA252, and the result revealed that emodin could damage the integrity of cell wall, leading to loss of intracellular components. In summary, our results showed ET-RPC could significantly inhibit bacterial growth of MRSA strains. Emodin was identified as the major compound with anti-MRSA activity; this activity was related to destruction of the integrity of the cell wall and cell membrane.

Human SAP is a novel peptidoglycan recognition protein that induces complement- independent phagocytosis of Staphylococcus aureus

PubMed Central

An, Jang-Hyun; Kurokawa, Kenji; Jung, Dong-Jun; Kim, Min-Jung; Kim, Chan-Hee; Fujimoto, Yukari; Fukase, Koichi; Coggeshall, K. Mark; Lee, Bok Luel

2014-01-01

The human pathogen Staphylococcus aureus is responsible for many community-acquired and hospital-associated infections and is associated with high mortality. Concern over the emergence of multidrug-resistant strains has renewed interest in the elucidation of host mechanisms that defend against S. aureus infection. We recently demonstrated that human serum mannose-binding lectin (MBL) binds to S. aureus wall teichoic acid (WTA), a cell wall glycopolymer, a discovery that prompted further screening to identify additional serum proteins that recognize S. aureus cell wall components. In this report, we incubated human serum with 10 different S. aureus mutants and determined that serum amyloid P component (SAP) bound specifically to a WTA-deficient S. aureus ΔtagO mutant, but not to tagO-complemented, WTA-expressing cells. Biochemical characterization revealed that SAP recognizes bacterial peptidoglycan as a ligand and that WTA inhibits this interaction. Although SAP binding to peptidoglycan was not observed to induce complement activation, SAP-bound ΔtagO cells were phagocytosed by human polymorphonuclear leukocytes in an Fcγ receptor-dependent manner. These results indicate that SAP functions as a host defense factor, similar to other peptidoglycan recognition proteins and nucleotide-binding oligomerization domain (NOD)-like receptors. PMID:23966633

Convergence of PASTA kinase and two-component signaling in response to cell wall stress in Enterococcus faecalis.

PubMed

Kellogg, Stephanie L; Kristich, Christopher J

2018-04-09

Two common signal transduction mechanisms used by bacteria to sense and respond to changing environments are two-component systems (TCSs) and eukaryotic-like Ser/Thr kinases and phosphatases (eSTK/Ps). Enterococcus faecalis is a Gram-positive bacterium and serious opportunistic pathogen that relies on both a TCS and an eSTK/P pathway for intrinsic resistance to cell wall-targeting antibiotics. The TCS consists of a histidine kinase (CroS) and response regulator (CroR) that become activated upon exposure of cells to cell wall-targeting antibiotics, leading to modulation of gene expression. The eSTK/P pathway consists of a transmembrane kinase (IreK) and its cognate phosphatase (IreP), which act antagonistically to mediate antibiotic resistance through an unknown mechanism. Because both CroS/R and IreK/P contribute to enterococcal resistance towards cell wall-targeting antibiotics, we hypothesized these signaling systems are intertwined. To test this hypothesis, we analyzed CroR phosphorylation and CroS/R-dependent gene expression to probe the influence of IreK and IreP on CroS/R signaling. In addition, we analyzed the phosphorylation state of CroS which revealed IreK-dependent phosphorylation of a Thr residue important for CroS function. Our results are consistent with a model in which IreK positively influences CroR-dependent gene expression through phosphorylation of CroS to promote antimicrobial resistance in E. faecalis Importance Two-component signaling systems (TCSs) and eukaryotic-like Ser/Thr kinases (eSTKs) are used by bacteria to sense and adapt to changing environments. Understanding how these pathways are regulated to promote bacterial survival is critical for a more complete understanding of bacterial stress responses and physiology. The opportunistic pathogen Enterococcus faecalis relies on both a TCS (CroS/R) and an eSTK (IreK) for intrinsic resistance to cell wall-targeting antibiotics. We probed the relationship between CroS/R and IreK, revealing convergence of IreK and the sensor kinase CroS to enhance signaling through CroS/R and increase antimicrobial resistance in E. faecalis This newly described example of eSTK/TCS convergence adds to our understanding of the signaling networks mediating antimicrobial resistance in E. faecalis . Copyright © 2018 American Society for Microbiology.

GanedenBC30 cell wall and metabolites: anti-inflammatory and immune modulating effects in vitro.

PubMed

Jensen, Gitte S; Benson, Kathleen F; Carter, Steve G; Endres, John R

2010-03-24

This study was performed to evaluate anti-inflammatory and immune modulating properties of the probiotic, spore-forming bacterial strain: Bacillus coagulans: GBI-30, (PTA-6086, GanedenBC30TM). In addition, cell wall and metabolite fractions were assayed separately to address whether biological effects were due to cell wall components only, or whether secreted compounds from live bacteria had additional biological properties. The spores were heat-activated, and bacterial cultures were grown. The culture supernatant was harvested as a source of metabolites (MTB), and the bacteria were used to isolate cell wall fragments (CW). Both of these fractions were compared in a series of in vitro assays. Both MTB and CW inhibited spontaneous and oxidative stress-induced ROS formation in human PMN cells and increased the phagocytic activity of PMN cells in response to bacteria-like carboxylated fluorospheres. Both fractions supported random PMN and f-MLP-directed PMN cell migration, indicating a support of immune surveillance and antibacterial defense mechanisms. In contrast, low doses of both fractions inhibited PMN cell migration towards the inflammatory mediators IL-8 and LTB4. The anti-inflammatory activity was strongest for CW, where the PMN migration towards IL-8 was inhibited down to dilutions of 1010.Both MTB and CW induced the expression of the CD69 activation marker on human CD3- CD56+ NK cells, and enhanced the expression of CD107a when exposed to K562 tumor cells in vitro.The fractions directly modulated cytokine production, inducing production of the Th2 cytokines IL-4, IL-6, and IL-10, and inhibiting production of IL-2.Both fractions further modulated mitogen-induced cytokine production in the following manner: Both fractions enhanced the PHA-induced production of IL-6 and reduced the PHA-induced production of TNF-alpha. Both fractions enhanced the PWM-induced production of TNF-alpha and IFN-gamma. In addition, MTB also enhanced both the PHA- and the PWM-induced expression of IL-10. The data suggest that consumption of GanedenBC30TM may introduce both cell wall components and metabolites that modulate inflammatory processes in the gut. Both the cell wall and the supernatant possess strong immune modulating properties in vitro. The anti-inflammatory effects, combined with direct induction of IL-10, are of interest with respect to possible treatment of inflammatory bowel diseases as well as in support of a healthy immune system.

GanedenBC30™ cell wall and metabolites: anti-inflammatory and immune modulating effects in vitro

PubMed Central

2010-01-01

Background This study was performed to evaluate anti-inflammatory and immune modulating properties of the probiotic, spore-forming bacterial strain: Bacillus coagulans: GBI-30, (PTA-6086, GanedenBC30TM). In addition, cell wall and metabolite fractions were assayed separately to address whether biological effects were due to cell wall components only, or whether secreted compounds from live bacteria had additional biological properties. The spores were heat-activated, and bacterial cultures were grown. The culture supernatant was harvested as a source of metabolites (MTB), and the bacteria were used to isolate cell wall fragments (CW). Both of these fractions were compared in a series of in vitro assays. Results Both MTB and CW inhibited spontaneous and oxidative stress-induced ROS formation in human PMN cells and increased the phagocytic activity of PMN cells in response to bacteria-like carboxylated fluorospheres. Both fractions supported random PMN and f-MLP-directed PMN cell migration, indicating a support of immune surveillance and antibacterial defense mechanisms. In contrast, low doses of both fractions inhibited PMN cell migration towards the inflammatory mediators IL-8 and LTB4. The anti-inflammatory activity was strongest for CW, where the PMN migration towards IL-8 was inhibited down to dilutions of 1010. Both MTB and CW induced the expression of the CD69 activation marker on human CD3- CD56+ NK cells, and enhanced the expression of CD107a when exposed to K562 tumor cells in vitro. The fractions directly modulated cytokine production, inducing production of the Th2 cytokines IL-4, IL-6, and IL-10, and inhibiting production of IL-2. Both fractions further modulated mitogen-induced cytokine production in the following manner: Both fractions enhanced the PHA-induced production of IL-6 and reduced the PHA-induced production of TNF-alpha. Both fractions enhanced the PWM-induced production of TNF-alpha and IFN-gamma. In addition, MTB also enhanced both the PHA- and the PWM-induced expression of IL-10. Conclusion The data suggest that consumption of GanedenBC30TM may introduce both cell wall components and metabolites that modulate inflammatory processes in the gut. Both the cell wall and the supernatant possess strong immune modulating properties in vitro. The anti-inflammatory effects, combined with direct induction of IL-10, are of interest with respect to possible treatment of inflammatory bowel diseases as well as in support of a healthy immune system. PMID:20331905

The lantibiotic mersacidin is a strong inducer of the cell wall stress response of Staphylococcus aureus

PubMed Central

Sass, Peter; Jansen, Andrea; Szekat, Christiane; Sass, Vera; Sahl, Hans-Georg; Bierbaum, Gabriele

2008-01-01

Background The lantibiotic mersacidin is an antimicrobial peptide of 20 amino acids that is ribosomally produced by Bacillus sp. strain HIL Y-85,54728. Mersacidin acts by complexing the sugar phosphate head group of the peptidoglycan precursor lipid II, thereby inhibiting the transglycosylation reaction of peptidoglycan biosynthesis. Results Here, we studied the growth of Staphylococcus aureus in the presence of subinhibitory concentrations of mersacidin. Transcriptional data revealed an extensive induction of the cell wall stress response, which is partly controlled by the two-component regulatory system VraSR. In contrast to other cell wall-active antibiotics such as vancomycin, very low concentrations of mersacidin (0.15 × MIC) were sufficient for induction. Interestingly, the cell wall stress response was equally induced in vancomycin intermediately resistant S. aureus (VISA) and in a highly susceptible strain. Since the transcription of the VraDE ABC transporter genes was induced up to 1700-fold in our experiments, we analyzed the role of VraDE in the response to mersacidin. However, the deletion of the vraE gene did not result in an increased susceptibility to mersacidin compared to the wild type strain. Moreover, the efficacy of mersacidin was not affected by an increased cell wall thickness, which is part of the VISA-type resistance mechanism and functions by trapping the vancomycin molecules in the cell wall before they reach lipid II. Therefore, the relatively higher concentration of mersacidin at the membrane might explain why mersacidin is such a strong inducer of VraSR compared to vancomycin. Conclusion In conclusion, mersacidin appears to be a strong inducer of the cell wall stress response of S. aureus at very low concentrations, which reflects its general mode of action as a cell wall-active peptide as well as its use of a unique target site on lipid II. Additionally, mersacidin does not seem to be a substrate for the resistance transporter VraDE. PMID:18947397

Systems Level Engineering of Plant Cell Wall Biosynthesis to Improve Biofuel Feedstock Quality

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazen, Samuel

2013-09-27

Our new regulatory model of cell wall biosynthesis proposes original network architecture with several newly incorporated components. The mapped set of protein-DNA interactions will serve as a foundation for 1) understanding the regulation of a complex and integral plant component and 2) the manipulation of crop species for biofuel and biotechnology purposes. This study revealed interesting and novel aspects of grass growth and development and further enforce the importance of a grass model system. By functionally characterizing a suite of genes, we have begun to improve the sparse model for transcription regulation of biomass accumulation in grasses. In the process,more » we have advanced methodology and brachy molecular genetic tools that will serve as valuable community resource.« less

Live cell and immuno-labeling techniques to study gravitational effects on single plant cells.

PubMed

Chebli, Youssef; Geitmann, Anja

2015-01-01

The constant force of gravity plays a primordial role in the ontogeny of all living organisms. Plants, for example, develop their roots and shoots in accordance with the direction of the gravitational vector. Any change in the magnitude and/or the direction of gravity has an important impact on the development of tissues and cells. In order to understand how the gravitational force affects plant cell growth and differentiation, we established two complementary experimental procedures with which the effect of hyper-gravity on single plant cell development can be assessed. The single model cell system we used is the pollen tube or male gametophyte which, because of its rapid growth behavior, is known for its instant response to external stresses. The physiological response of the pollen tube can be assessed in a quantitative manner based on changes in the composition and spatial distribution of its cell wall components and in the precisely defined pattern of its very dynamic cytoplasmic streaming. Here, we provide a detailed description of the steps required for the immuno-localization of various cell wall components using microwave-assisted techniques and we explain how live imaging of the intracellular traffic can be achieved under hyper-gravity conditions.

Chitinases are essential for sexual development but not vegetative growth in Cryptococcus neoformans.

PubMed

Baker, Lorina G; Specht, Charles A; Lodge, Jennifer K

2009-11-01

Cryptococcus neoformans is an opportunistic pathogen that mainly infects immunocompromised individuals. The fungal cell wall of C. neoformans is an excellent target for antifungal therapies since it is an essential organelle that provides cell structure and integrity. Importantly, it is needed for localization or attachment of known virulence factors, including melanin, phospholipase, and the polysaccharide capsule. The polysaccharide fraction of the cryptococcal cell wall is a complex structure composed of chitin, chitosan, and glucans. Chitin is an indispensable component of many fungal cell walls that contributes significantly to cell wall strength and integrity. Fungal cell walls are very dynamic, constantly changing during cell division and morphogenesis. Hydrolytic enzymes, such as chitinases, have been implicated in the maintenance of cell wall plasticity and separation of the mother and daughter cells at the bud neck during vegetative growth in yeast. In C. neoformans we identified four predicted endochitinases, CHI2, CHI21, CHI22, and CHI4, and a predicted exochitinase, hexosaminidase, HEX1. Enzymatic analysis indicated that Chi2, Chi22, and Hex1 actively degraded chitinoligomeric substrates. Chi2 and Hex1 activity was associated mostly with the cellular fraction, and Chi22 activity was more prominent in the supernatant. The enzymatic activity of Hex1 increased when grown in media containing only N-acetylglucosamine as a carbon source, suggesting that its activity may be inducible by chitin degradation products. Using a quadruple endochitinase deletion strain, we determined that the endochitinases do not affect the growth or morphology of C. neoformans during asexual reproduction. However, mating assays indicated that Chi2, Chi21, and Chi4 are each involved in sexual reproduction. In summary, the endochitinases were found to be dispensable for routine vegetative growth but not sexual reproduction.

Hedgehog and Resident Vascular Stem Cell Fate

PubMed Central

Mooney, Ciaran J.; Hakimjavadi, Roya; Fitzpatrick, Emma; Kennedy, Eimear; Walls, Dermot; Morrow, David; Redmond, Eileen M.; Cahill, Paul A.

2015-01-01

The Hedgehog pathway is a pivotal morphogenic driver during embryonic development and a key regulator of adult stem cell self-renewal. The discovery of resident multipotent vascular stem cells and adventitial progenitors within the vessel wall has transformed our understanding of the origin of medial and neointimal vascular smooth muscle cells (SMCs) during vessel repair in response to injury, lesion formation, and overall disease progression. This review highlights the importance of components of the Hh and Notch signalling pathways within the medial and adventitial regions of adult vessels, their recapitulation following vascular injury and disease progression, and their putative role in the maintenance and differentiation of resident vascular stem cells to vascular lineages from discrete niches within the vessel wall. PMID:26064136

Cellulose-pectin composite hydrogels: Intermolecular interactions and material properties depend on order of assembly.

PubMed

Lopez-Sanchez, Patricia; Martinez-Sanz, Marta; Bonilla, Mauricio R; Wang, Dongjie; Gilbert, Elliot P; Stokes, Jason R; Gidley, Michael J

2017-04-15

Plant cell walls have a unique combination of strength and flexibility however, further investigations are required to understand how those properties arise from the assembly of the relevant biopolymers. Recent studies indicate that Ca 2+ -pectates can act as load-bearing components in cell walls. To investigate this proposed role of pectins, bioinspired wall models were synthesised based on bacterial cellulose containing pectin-calcium gels by varying the order of assembly of cellulose/pectin networks, pectin degree of methylesterification and calcium concentration. Hydrogels in which pectin-calcium assembly occurred prior to cellulose synthesis showed evidence for direct cellulose/pectin interactions from small-angle scattering (SAXS and SANS), had the densest networks and the lowest normal stress. The strength of the pectin-calcium gel affected cellulose structure, crystallinity and material properties. The results highlight the importance of the order of assembly on the properties of cellulose composite networks and support the role of pectin in the mechanics of cell walls. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dynamic Fungal Cell Wall Architecture in Stress Adaptation and Immune Evasion.

PubMed

Hopke, Alex; Brown, Alistair J P; Hall, Rebecca A; Wheeler, Robert T

2018-04-01

Deadly infections from opportunistic fungi have risen in frequency, largely because of the at-risk immunocompromised population created by advances in modern medicine and the HIV/AIDS pandemic. This review focuses on dynamics of the fungal polysaccharide cell wall, which plays an outsized role in fungal pathogenesis and therapy because it acts as both an environmental barrier and as the major interface with the host immune system. Human fungal pathogens use architectural strategies to mask epitopes from the host and prevent immune surveillance, and recent work elucidates how biotic and abiotic stresses present during infection can either block or enhance masking. The signaling components implicated in regulating fungal immune recognition can teach us how cell wall dynamics are controlled, and represent potential targets for interventions designed to boost or dampen immunity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Sporothrix schenckii sensu stricto and Sporothrix brasiliensis Are Differentially Recognized by Human Peripheral Blood Mononuclear Cells

PubMed Central

Martínez-Álvarez, José A.; Pérez-García, Luis A.; Mellado-Mojica, Erika; López, Mercedes G.; Martínez-Duncker, Iván; Lópes-Bezerra, Leila M.; Mora-Montes, Héctor M.

2017-01-01

Sporothrix schenckii sensu stricto and S. brasiliensis are usually associated to sporotrichosis, a subcutaneous mycosis worldwide distributed. Comparative analyses between these two species indicate they contain genetic and physiological differences that are likely to impact the interaction with host cells. Here, we study the composition of the cell wall from conidia, yeast-like cells and germlings of both species and found they contained the same sugar composition. The carbohydrate proportion in the S. schenckii sensu stricto wall was similar across the three cell morphologies, with exception in the chitin content, which was significantly different in the three morphologies. The cell wall from germlings showed lower rhamnose content and higher glucose levels than other cell morphologies. In S. brasiliensis, the wall sugars were constant in the three morphologies, but glucose was lower in yeast-like cells. In S. schenckii sensu stricto cells most of chitin and β1,3-glucan were underneath wall components, but in S. brasiliensis germlings, chitin was exposed at the cell surface, and β1,3-glucan was found in the outer part of the conidia wall. We also compared the ability of these cells to stimulate cytokine production by human peripheral blood mononuclear cells. The three S. schenckii sensu stricto morphologies stimulated increased levels of pro-inflammatory cytokines, when compared to S. brasiliensis cells; while the latter, with exception of conidia, stimulated higher IL-10 levels. Dectin-1 was a key receptor for cytokine production during stimulation with the three morphologies of S. schenckii sensu stricto, but dispensable for cytokine production stimulated by S. brasiliensis germlings. TLR2 and TLR4 were also involved in the sensing of Sporothrix cells, with a major role for the former during cytokine stimulation. Mannose receptor had a minor contribution during cytokine stimulation by S. schenckii sensu stricto yeast-like cells and germlings, but S. schenckii sensu stricto conidia and S. brasiliensis yeast-like cells stimulated pro-inflammatory cytokines via this receptor. In conclusion, S. brasiliensis and S. schenckii sensu stricto, have similar wall composition, which undergoes changes depending on the cell morphology. These differences in the cell wall composition, are likely to influence the contribution of immune receptors during cytokine stimulation by human monocytes. PMID:28539922

Effects of cell wall components on the functionality of wheat gluten.

PubMed

Autio, K

2006-01-01

Normal white wheat flours and especially whole meal flour contain solids from the inner endosperm cell walls, from germ, aleurone layer and the outer layers of cereal grains. These solids can prevent either gluten formation or gas cell structure. The addition of small amounts of pericarp layers (1-2%) to wheat flour had a marked detrimental effect on loaf volume. Microstructural studies indicated that in particular the epicarp hairs appeared to disturb the gas cell structure. The detrimental effects of insoluble cell walls can be prevented by using endoxylanases. It has been shown that some oxidative enzymes, naturally present in flour or added to the dough, will oxidise water-extractable arabinoxylans via ferulic acid bridges, and the resulting arabinoxylan gel will hinder gluten formation. The negative effects of water-unextractable arabinoxylans on gluten yield and rheological properties can be compensated by the addition of ferulic acid. Free ferulic acid can probably prevent arabinoxylan cross-linking via ferulic acid.

Chitinases in Pneumocystis carinii pneumonia

PubMed Central

Villegas, Leah R.; Kottom, Theodore J.

2014-01-01

Pneumocystis pneumonia remains an important complication of immune suppression. The cell wall of Pneumocystis has been demonstrated to potently stimulate host inflammatory responses, with most studies focusing on β-glucan components of the Pneumocystis cell wall. In the current study, we have elaborated the potential role of chitins and chitinases in Pneumocystis pneumonia. We demonstrated differential host mammalian chitinase expression during Pneumocystis pneumonia. We further characterized a chitin synthase gene in Pneumocystis carinii termed Pcchs5, a gene with considerable homolog to the fungal chitin biosynthesis protein Chs5. We also observed the impact of chitinase digestion on Pneumocystis-induced host inflammatory responses by measuring TNFα release and mammalian chitinase expression by cultured lung epithelial and macrophage cells stimulated with Pneumocystis cell wall isolates in the presence and absence of exogenous chitinase digestion. These findings provide evidence supporting a chitin biosynthetic pathway in Pneumocystis organisms and that chitinases modulate inflammatory responses in lung cells. We further demonstrate lung expression of chitinase molecules during Pneumocystis pneumonia. PMID:22535444

The putative hydrolase YycJ (WalJ) affects the coordination of cell division with DNA replication in Bacillus subtilis and may play a conserved role in cell wall metabolism.

PubMed

Biller, Steven J; Wayne, Kyle J; Winkler, Malcolm E; Burkholder, William F

2011-02-01

Bacteria must accurately replicate and segregate their genetic information to ensure the production of viable daughter cells. The high fidelity of chromosome partitioning is achieved through mechanisms that coordinate cell division with DNA replication. We report that YycJ (WalJ), a predicted member of the metallo-β-lactamase superfamily found in most low-G+C Gram-positive bacteria, contributes to the fidelity of cell division in Bacillus subtilis. B. subtilis ΔwalJ (ΔwalJ(Bsu)) mutants divide over unsegregated chromosomes more frequently than wild-type cells, and this phenotype is exacerbated when DNA replication is inhibited. Two lines of evidence suggest that WalJ(Bsu) and its ortholog in the Gram-positive pathogen Streptococcus pneumoniae, WalJ(Spn) (VicX), play a role in cell wall metabolism: (i) strains of B. subtilis and S. pneumoniae lacking walJ exhibit increased sensitivity to a narrow spectrum of cephalosporin antibiotics, and (ii) reducing the expression of a two-component system that regulates genes involved in cell wall metabolism, WalRK (YycFG), renders walJ essential for growth in B. subtilis, as observed previously with S. pneumoniae. Together, these results suggest that the enzymatic activity of WalJ directly or indirectly affects cell wall metabolism and is required for accurate coordination of cell division with DNA replication.

An Environmentally Friendly Method for Testing Photocatalytic Inactivation of Cyanobacterial Propagation on a Hybrid Ag-TiO2 Photocatalyst under Solar Illumination

PubMed Central

Chang, Shu-Yu; Huang, Winn-Jung; Lu, Ben-Ren; Fang, Guor-Cheng; Chen, Yeah; Chen, Hsiu-Lin; Chang, Ming-Chin; Hsu, Cheng-Feng

2015-01-01

Cyanobacteria were inactivated under sunlight using mixed phase silver (Ag) and deposited titanium dioxide (TiO2) coated on the surface of diatomite (DM) as a hybrid photocatalyst (Ag-TiO2/DM). The endpoints of dose-response experiments were chlorophyll a, photosynthetic efficiency, and flow cytometry measurements. In vitro experiments revealed that axenic cultures of planktonic cyanobacteria lost their photosynthetic activity following photocatalyzed exposure to sunlight for more than 24 h. Nearly 92% of Microcystis aeruginosa cells lost their photosynthetic activity, and their cell morphology was severely damaged within 24 h of the reaction. Preliminary carbon-14 (14CO3−2) results suggest that the complete inactivation of cyanobacteria arises from damage to cell wall components (peroxidation). A small concomitant increase in cell wall disorder and a consequent decrease in cell wall functional groups increase the cell wall fluidity prior to cell lysis. A high dosage of Ag-TiO2/DM during photocatalysis increased the concentration of extracellular polymeric substances (EPSs) in the Microcystis aeruginosa suspension by up to approximately 260%. However, photocatalytic treatment had a small effect on the disinfection by-product (DBP) precursor, as revealed by only a slight increase in the formation of trihalomethanes (THMs) and haloacetic acids (HAAs). PMID:26690465

Single-molecule analysis of the major glycopolymers of pathogenic and non-pathogenic yeast cells

NASA Astrophysics Data System (ADS)

El-Kirat-Chatel, Sofiane; Beaussart, Audrey; Alsteens, David; Sarazin, Aurore; Jouault, Thierry; Dufrêne, Yves F.

2013-05-01

Most microbes are coated with carbohydrates that show remarkable structural variability and play a crucial role in mediating microbial-host interactions. Understanding the functions of cell wall glycoconjugates requires detailed knowledge of their molecular organization, diversity and heterogeneity. Here we use atomic force microscopy (AFM) with tips bearing specific probes (lectins, antibodies) to analyze the major glycopolymers of pathogenic and non-pathogenic yeast cells at molecular resolution. We show that non-ubiquitous β-1,2-mannans are largely exposed on the surface of native cells from pathogenic Candida albicans and C. glabrata, the former species displaying the highest glycopolymer density and extensions. We also find that chitin, a major component of the inner layer of the yeast cell wall, is much more abundant in C. albicans. These differences in molecular properties, further supported by flow cytometry measurements, may play an important role in strengthening cell wall mechanics and immune interactions. This study demonstrates that single-molecule AFM, combined with immunological and fluorescence methods, is a powerful platform in fungal glycobiology for probing the density, distribution and extension of specific cell wall glycoconjugates. In nanomedicine, we anticipate that this new form of AFM-based nanoglycobiology will contribute to the development of sugar-based drugs, immunotherapeutics, vaccines and diagnostics.

Electron microscopy of vesicular-arbuscular mycorrhizae of yellow poplar. II. Intracellular hyphae and vesicles.

PubMed

Kinden, D A; Brown, M F

1975-11-01

Intracellular hyphae and vesicles in mycorrhizal roots of yellow poplar were examined by electron microscopy. An investing layer of host wall material and cytoplasm enclosed the endophyte within the cells. Young developing hyphae contained abundant cytoplasm and few vacuoles. As hyphae matured, they became highly vacuolated and accumulated carbohydrate (glycogen) and lipid reserves. Mature vesicles were engorged with lipid droplets, possessed a trilaminate wall and were also enclosed by host wall material and cytoplasm. Compared with uninfected cells, infected cortical cells showed an increase in cytoplasmic volume, enlarged nuclei, and a reduction of starch reserves. Host nuclei were always proximal to the hyphae during hyphal development and deterioration. While other cytoplasmic components of infected and uninfected cells were comparable large electron-dense bodies occurred in vacuoles of most cells containing hyphae. Deterioration of intracellular hyphae occurred throughout the samples examined. Septa separated functional and degenerating portions of the hyphae. Hyphal deterioration involved degeneration and ultimate disappearance of fungal cytoplasm as well as collapse of hyphal walls. Based on these observations, the authors hypothesize that deterioration of the endophyte may release significant quantities of mineral nutrients, via hyphal contents, which are absorbed by the host.

Substantial decrease in cell wall α-1,3-glucan caused by disruption of the kexB gene encoding a subtilisin-like processing protease in Aspergillus oryzae.

PubMed

Mizutani, Osamu; Shiina, Matsuko; Yoshimi, Akira; Sano, Motoaki; Watanabe, Takeshi; Yamagata, Youhei; Nakajima, Tasuku; Gomi, Katsuya; Abe, Keietsu

2016-09-01

Disruption of the kexB encoding a subtilisin-like processing protease in Aspergillus oryzae (ΔkexB) leads to substantial morphological defects when the cells are grown on Czapek-Dox agar plates. We previously found that the disruption of kexB causes a constitutive activation of the cell wall integrity pathway. To understand how the disruption of the kexB affects cell wall organization and components, we analyzed the cell wall of ΔkexB grown on the plates. The results revealed that both total N-acetylglucosamine content, which constitutes chitin, and chitin synthase activities were increased. Whereas total glucose content, which constitutes β-1,3-glucan and α-1,3-glucan, was decreased; this decrease was attributed to a remarkable decrease in α-1,3-glucan. Additionally, the β-1,3-glucan in the alkali-insoluble fraction of the ΔkexB showed a high degree of polymerization. These results suggested that the loss of α-1,3-glucan in the ΔkexB was compensated by increases in the chitin content and the average degree of β-1,3-glucan polymerization.

The chitin connection.

PubMed

Goldman, David L; Vicencio, Alfin G

2012-01-01

Chitin, a polymer of N-acetylglucosamine, is an essential component of the fungal cell wall. Chitosan, a deacetylated form of chitin, is also important in maintaining cell wall integrity and is essential for Cryptococcus neoformans virulence. In their article, Gilbert et al. [N. M. Gilbert, L. G. Baker, C. A. Specht, and J. K. Lodge, mBio 3(1):e00007-12, 2012] demonstrate that the enzyme responsible for chitosan synthesis, chitin deacetylase (CDA), is differentially attached to the cell membrane and wall. Bioactivity is localized to the cell membrane, where it is covalently linked via a glycosylphosphatidylinositol (GPI) anchor. Findings from this study significantly enhance our understanding of cryptococcal cell wall biology. Besides the role of chitin in supporting structural stability, chitin and host enzymes with chitinase activity have an important role in host defense and modifying the inflammatory response. Thus, chitin appears to provide a link between the fungus and host that involves both innate and adaptive immune responses. Recently, there has been increased attention to the role of chitinases in the pathogenesis of allergic inflammation, especially asthma. We review these findings and explore the possible connection between fungal infections, the induction of chitinases, and asthma.

Plural output optimetric sample cell and analysis system

NASA Technical Reports Server (NTRS)

Haley, F. C. (Inventor)

1971-01-01

An apparatus suitable for receiving a sample for optimetric analysis includes a sample cell comprising an opaque hollow tube. Several apertures are defined in the wall of the tubing and a lens barrel which extends beyond to opposite surfaces of the wall is supported within at least one of the apertures. A housing is provided with one channel for receiving the sample cell and a series of channels extending from the exterior housing to the sample cell apertures. A filter element is housed in each of these latter channels. These channels slidingly receive an excitation light source for a photodetector cell to permit selective focusing. A sample cell containing at least three apertures in the walls can be mounted for rotation relative to a light source or photoconduction means for simultaneous or alternative optimetric determination of the components of a single sample. The sample cell is fabricated by supporting a lens barrel within the aperture. A molten portion of glass is deposited in the lens barrel and cooled while in a horizontal position to form a lens having an acceptable angle.

In vitro bioassessment of the immunomodulatory activity of Saccharomyces cerevisiae components using bovine macrophages and Mycobacterium avium ssp. paratuberculosis.

PubMed

Li, Z; Kang, H; You, Q; Ossa, F; Mead, P; Quinton, M; Karrow, N A

2018-04-11

The yeast Saccharomyces cerevisiae and its components are used for the prevention and treatment of enteric disease in different species; therefore, they may also be useful for preventing Johne's disease, a chronic inflammatory bowel disease of ruminants caused by Mycobacterium avium ssp. paratuberculosis (MAP). The objective of this study was to identify potential immunomodulatory S. cerevisiae components using a bovine macrophage cell line (BOMAC). The BOMAC phagocytic activity, reactive oxygen species production, and immune-related gene (IL6, IL10, IL12p40, IL13, IL23), transforming growth factor β, ARG1, CASP1, and inducible nitric oxide synthase expression were investigated when BOMAC were cocultured with cell wall components from 4 different strains (A, B, C, and D) and 2 forms of dead yeast from strain A. The BOMAC phagocytosis of mCherry-labeled MAP was concentration-dependently attenuated when BOMAC were cocultured with yeast components for 6 h. Each yeast derivative also induced a concentration-dependent increase in BOMAC reactive oxygen species production after a 6-h exposure. In addition, BOMAC mRNA expression of the immune-related genes was investigated after 6 and 24 h of exposure to yeast components. All yeast components were found to regulate the immunomodulatory genes of BOMAC; however, the response varied among components and over time. The in vitro bioassessment studies reported here suggest that dead yeast and its cell wall components may be useful for modulating macrophage function before or during MAP infection. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Mechanisms of stimulation of interleukin-1 beta and tumor necrosis factor-alpha by Mycobacterium tuberculosis components.

PubMed Central

Zhang, Y; Doerfler, M; Lee, T C; Guillemin, B; Rom, W N

1993-01-01

The granulomatous immune response in tuberculosis is characterized by delayed hypersensitivity and is mediated by various cytokines released by the stimulated mononuclear phagocytes, including tumor necrosis factor-alpha (TNF alpha) and IL-1 beta. We have demonstrated that Mycobacterium tuberculosis cell wall component lipoarabinomannan (LAM), mycobacterial heat shock protein-65 kD, and M. tuberculosis culture filtrate, devoid of LPS as assessed by the Amebocyte Lysate assay, stimulate the production of TNF alpha and IL-1 beta proteins and mRNA from mononuclear phagocytes (THP-1 cells). The effect of LAM on the release of these cytokines was specific, as only LAM stimulation was inhibited by anti-LAM monoclonal antibody. Interestingly, we found that LAM and Gram-negative bacterial cell wall-associated endotoxin LPS may share a similar mechanism in their stimulatory action as demonstrated by inhibition of TNF alpha and IL-1 beta release by monoclonal antibodies to CD14. Anti-CD14 monoclonal antibody MY4 inhibited both TNF alpha and IL-1 beta release with LAM and LPS but no effect was observed with other mycobacterial proteins. An isotype antibody control did not inhibit release of cytokines under the same experimental conditions. M. tuberculosis and its components upregulated IL-1 beta and TNF alpha mRNAs in THP-1 cells. Nuclear run-on assay for IL-1 beta demonstrated that LAM increased the transcription rate. The induction of IL-1 beta was regulated at the transcriptional level, in which these stimuli acted through cis-acting element(s) on the 5' flanking region of the IL-1 beta genomic DNA. M. tuberculosis cell wall component LAM acts similarly to LPS in activating mononuclear phagocyte cytokine TNF alpha and IL-1 beta release through CD14 and synthesis at the transcriptional level; both cytokines are key participants in the host immune response to tuberculosis. Images PMID:7683696

PKC1 is essential for protection against both oxidative and nitrosative stresses, cell integrity, and normal manifestation of virulence factors in the pathogenic fungus Cryptococcus neoformans.

PubMed

Gerik, Kimberly J; Bhimireddy, Sujit R; Ryerse, Jan S; Specht, Charles A; Lodge, Jennifer K

2008-10-01

Cell wall integrity is crucial for fungal growth, survival, and pathogenesis. Responses to environmental stresses are mediated by the highly conserved Pkc1 protein and its downstream components. In this study, we demonstrate that both oxidative and nitrosative stresses activate the PKC1 cell integrity pathway in wild-type cells, as measured by phosphorylation of Mpk1, the terminal protein in the PKC1 phosphorylation cascade. Furthermore, deletion of PKC1 shows that this gene is essential for defense against both oxidative and nitrosative stresses; however, other genes involved directly in the PKC1 pathway are dispensable for protection against these stresses. This suggests that Pkc1 may have multiple and alternative functions other than activating the mitogen-activated protein kinase cascade from a "top-down" approach. Deletion of PKC1 also causes osmotic instability, temperature sensitivity, severe sensitivity to cell wall-inhibiting agents, and alterations in capsule and melanin. Furthermore, the vital cell wall components chitin and its deacetylated form chitosan appear to be mislocalized in a pkc1Delta strain, although this mutant contains wild-type levels of both of these polymers. These data indicate that loss of Pkc1 has pleiotropic effects because it is central to many functions either dependent on or independent of PKC1 pathway activation. Notably, this is the first time that Pkc1 has been implicated in protection against nitrosative stress in any organism.

PKC1 Is Essential for Protection against both Oxidative and Nitrosative Stresses, Cell Integrity, and Normal Manifestation of Virulence Factors in the Pathogenic Fungus Cryptococcus neoformans▿ †

PubMed Central

Gerik, Kimberly J.; Bhimireddy, Sujit R.; Ryerse, Jan S.; Specht, Charles A.; Lodge, Jennifer K.

2008-01-01

Cell wall integrity is crucial for fungal growth, survival, and pathogenesis. Responses to environmental stresses are mediated by the highly conserved Pkc1 protein and its downstream components. In this study, we demonstrate that both oxidative and nitrosative stresses activate the PKC1 cell integrity pathway in wild-type cells, as measured by phosphorylation of Mpk1, the terminal protein in the PKC1 phosphorylation cascade. Furthermore, deletion of PKC1 shows that this gene is essential for defense against both oxidative and nitrosative stresses; however, other genes involved directly in the PKC1 pathway are dispensable for protection against these stresses. This suggests that Pkc1 may have multiple and alternative functions other than activating the mitogen-activated protein kinase cascade from a “top-down” approach. Deletion of PKC1 also causes osmotic instability, temperature sensitivity, severe sensitivity to cell wall-inhibiting agents, and alterations in capsule and melanin. Furthermore, the vital cell wall components chitin and its deacetylated form chitosan appear to be mislocalized in a pkc1Δ strain, although this mutant contains wild-type levels of both of these polymers. These data indicate that loss of Pkc1 has pleiotropic effects because it is central to many functions either dependent on or independent of PKC1 pathway activation. Notably, this is the first time that Pkc1 has been implicated in protection against nitrosative stress in any organism. PMID:18689526

Downregulation of a UDP-Arabinomutase Gene in Switchgrass (Panicum virgatum L.) Results in Increased Cell Wall Lignin While Reducing Arabinose-Glycans

DOE PAGES

Willis, Jonathan D.; Smith, James A.; Mazarei, Mitra; ...

2016-10-26

Switchgrass (Panicum virgatum L.) is a C 4 perennial prairie grass and a dedicated feedstock for lignocellulosic biofuels. Saccharification and biofuel yields are inhibited by the plant cell wall's natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and cross-link other cell wall polymers. Grasses predominately have Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP) linked to arabinofuranose (Araf). A family of UDP-arabinopyranose mutase (UAM)/reversible glycosylated polypeptides catalyze the interconversion between UDP-arabinopyranose (UDP-Arap) and UDP-Araf. The expression ofmore » a switchgrass arabinoxylan biosynthesis pathway gene, PvUAM1, was decreased via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Southern blot analysis revealed each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise similar in morphology to the non-transgenic control. Cell wall-associated arabinose was decreased in leaves and stems by over 50%, but there was an increase in cellulose. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control. Plants with attenuated PvUAM1 transcript had increased cellulose and lignin in cell walls. A decrease in cell wall-associated arabinose was expected, which was likely caused by fewer Araf residues in the arabinoxylan. The decrease in arabinoxylan may cause a compensation response to maintain cell wall integrity by increasing cellulose and lignin biosynthesis. In cases in which increased lignin is desired, e.g., feedstocks for carbon fiber production, downregulated UAM1 coupled with altered expression of other arabinoxylan biosynthesis genes might result in even higher production of lignin in biomass.« less

Downregulation of a UDP-Arabinomutase Gene in Switchgrass (Panicum virgatum L.) Results in Increased Cell Wall Lignin While Reducing Arabinose-Glycans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willis, Jonathan D.; Smith, James A.; Mazarei, Mitra

Switchgrass (Panicum virgatum L.) is a C 4 perennial prairie grass and a dedicated feedstock for lignocellulosic biofuels. Saccharification and biofuel yields are inhibited by the plant cell wall's natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and cross-link other cell wall polymers. Grasses predominately have Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP) linked to arabinofuranose (Araf). A family of UDP-arabinopyranose mutase (UAM)/reversible glycosylated polypeptides catalyze the interconversion between UDP-arabinopyranose (UDP-Arap) and UDP-Araf. The expression ofmore » a switchgrass arabinoxylan biosynthesis pathway gene, PvUAM1, was decreased via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Southern blot analysis revealed each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise similar in morphology to the non-transgenic control. Cell wall-associated arabinose was decreased in leaves and stems by over 50%, but there was an increase in cellulose. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control. Plants with attenuated PvUAM1 transcript had increased cellulose and lignin in cell walls. A decrease in cell wall-associated arabinose was expected, which was likely caused by fewer Araf residues in the arabinoxylan. The decrease in arabinoxylan may cause a compensation response to maintain cell wall integrity by increasing cellulose and lignin biosynthesis. In cases in which increased lignin is desired, e.g., feedstocks for carbon fiber production, downregulated UAM1 coupled with altered expression of other arabinoxylan biosynthesis genes might result in even higher production of lignin in biomass.« less

Phosphoproteomic Analysis of Protein Kinase C Signaling in Saccharomyces cerevisiae Reveals Slt2 Mitogen-activated Protein Kinase (MAPK)-dependent Phosphorylation of Eisosome Core Components*

PubMed Central

Mascaraque, Victoria; Hernáez, María Luisa; Jiménez-Sánchez, María; Hansen, Rasmus; Gil, Concha; Martín, Humberto; Cid, Víctor J.; Molina, María

2013-01-01

The cell wall integrity (CWI) pathway of the model organism Saccharomyces cerevisiae has been thoroughly studied as a paradigm of the mitogen-activated protein kinase (MAPK) pathway. It consists of a classic MAPK module comprising the Bck1 MAPK kinase kinase, two redundant MAPK kinases (Mkk1 and Mkk2), and the Slt2 MAPK. This module is activated under a variety of stimuli related to cell wall homeostasis by Pkc1, the only member of the protein kinase C family in budding yeast. Quantitative phosphoproteomics based on stable isotope labeling of amino acids in cell culture is a powerful tool for globally studying protein phosphorylation. Here we report an analysis of the yeast phosphoproteome upon overexpression of a PKC1 hyperactive allele that specifically activates CWI MAPK signaling in the absence of external stimuli. We found 82 phosphopeptides originating from 43 proteins that showed enhanced phosphorylation in these conditions. The MAPK S/T-P target motif was significantly overrepresented in these phosphopeptides. Hyperphosphorylated proteins provide putative novel targets of the Pkc1–cell wall integrity pathway involved in diverse functions such as the control of gene expression, protein synthesis, cytoskeleton maintenance, DNA repair, and metabolism. Remarkably, five components of the plasma-membrane-associated protein complex known as eisosomes were found among the up-regulated proteins. We show here that Pkc1-induced phosphorylation of the eisosome core components Pil1 and Lsp1 was not exerted directly by Pkc1, but involved signaling through the Slt2 MAPK module. PMID:23221999

Absence of arabinan in the side chains of the pectic polysaccharides strongly associated with cell walls of Nicotiana plumbaginifolia non-organogenic callus with loosely attached constituent cells.

PubMed

Iwai, H; Ishii, T; Satoh, S

2001-10-01

When leaf disks from haploid plants of Nicotiana plumbaginifolia Viv. were transformed with T-DNA and cultured on shoot-inducing medium, nonorganogenic callus. designated nolac (for non-organogenic callus with loosely attached cells), appeared on approximately 7% of leaf disks. In contrast, normal callus was generated on T-DNA-transformed leaf disks from diploid plants and on non-transformed leaf disks from haploid and diploid plants. Transmission electron microscopy revealed that the middle lamellae and the cell walls of one line of mutant callus (nolac-H14) were barely stained by ruthenium red. even after demethylesterification with NaOH, whereas the entire cell wall and the middle lamella were strongly stained in normal callus. In cultures of nolac-H14 callus, the level of sugar components of pectic polysaccharides in the hemicellulose fraction was reduced and that in the culture medium was elevated, as compared with cultures of normal callus. These results indicate that pectic polysaccharides are not retained in the cell walls and middle lamellae of nolac-H14 callus. In nolac-H14, the ratio of arabinose to galactose was low in the pectic polysaccharides purified from all cell wall fractions and from the medium, in particular, in the hemicellulose fractions. The low levels of arabinofuranosyl (T-Araf, 5-Araf, 2,5-Araf, and 3,5-Araf) residues in the pectic polysaccharides of the hemicellulosic fraction of nolac-H,14 indicated that no neutral-sugar side chains, composed mainly of linear arabinan. were present in nolac-H14. Arabinose-rich pectins. which are strongly associated with cellulose-hemicellulose complexes, might play an important role in intercellular attachment in the architecture of the cell wall.

Epigallocatechin gallate incorporation into lignin enhances the alkaline delignification and enzymatic saccharification of cell walls

PubMed Central

2012-01-01

Background Lignin is an integral component of the plant cell wall matrix but impedes the conversion of biomass into biofuels. The plasticity of lignin biosynthesis should permit the inclusion of new compatible phenolic monomers such as flavonoids into cell wall lignins that are consequently less recalcitrant to biomass processing. In the present study, epigallocatechin gallate (EGCG) was evaluated as a potential lignin bioengineering target for rendering biomass more amenable to processing for biofuel production. Results In vitro peroxidase-catalyzed polymerization experiments revealed that both gallate and pyrogallyl (B-ring) moieties in EGCG underwent radical cross-coupling with monolignols mainly by β–O–4-type cross-coupling, producing benzodioxane units following rearomatization reactions. Biomimetic lignification of maize cell walls with a 3:1 molar ratio of monolignols and EGCG permitted extensive alkaline delignification of cell walls (72 to 92%) that far exceeded that for lignified controls (44 to 62%). Alkali-insoluble residues from EGCG-lignified walls yielded up to 34% more glucose and total sugars following enzymatic saccharification than lignified controls. Conclusions It was found that EGCG readily copolymerized with monolignols to become integrally cross-coupled into cell wall lignins, where it greatly enhanced alkaline delignification and subsequent enzymatic saccharification. Improved delignification may be attributed to internal trapping of quinone-methide intermediates to prevent benzyl ether cross-linking of lignin to structural polysaccharides during lignification, and to the cleavage of ester intra-unit linkages within EGCG during pretreatment. Overall, our results suggest that apoplastic deposition of EGCG for incorporation into lignin would be a promising plant genetic engineering target for improving the delignification and saccharification of biomass crops. PMID:22889353

Lysozyme as an alternative to growth promoting antibiotics in swine production

USDA-ARS?s Scientific Manuscript database

Lysozyme is a naturally occurring enzyme found in bodily secretions such as tears, saliva, and milk. It functions as an antimicrobial agent by cleaving the peptidoglycan component of bacterial cell walls, which leads to cell death. Antibiotics are also antimicrobials and have been fed at subtherape...

Chemical components of heartwood and sapwood of common Yew (Taxus baccata L.).

PubMed

Mertoğlu-Elmas, Gülnur

2003-10-01

Cell-wall components and solubility characteristics of the heartwood and sapwood of Taxus baccata L. were determined by methods of wood analysis and the differences between heartwood and sapwood were established. When we observe the data obtained, it is seen that the amount of extractive material found in the heartwood is substantially higher than the sapwood. The extractive material in Taxus baccata L. is originated from the hidden epithelial cells surrounded by resin canals.

2-Fluoro-L-Fucose Is a Metabolically Incorporated Inhibitor of Plant Cell Wall Polysaccharide Fucosylation

PubMed Central

Wallace, Ian S.

2015-01-01

The monosaccharide L-fucose (L-Fuc) is a common component of plant cell wall polysaccharides and other plant glycans, including the hemicellulose xyloglucan, pectic rhamnogalacturonan-I (RG-I) and rhamnogalacturonan-II (RG-II), arabinogalactan proteins, and N-linked glycans. Mutations compromising the biosynthesis of many plant cell wall polysaccharides are lethal, and as a result, small molecule inhibitors of plant cell wall polysaccharide biosynthesis have been developed because these molecules can be applied at defined concentrations and developmental stages. In this study, we characterize novel small molecule inhibitors of plant fucosylation. 2-fluoro-L-fucose (2F-Fuc) analogs caused severe growth phenotypes when applied to Arabidopsis seedlings, including reduced root growth and altered root morphology. These phenotypic defects were dependent upon the L-Fuc salvage pathway enzyme L-Fucose Kinase/ GDP-L-Fucose Pyrophosphorylase (FKGP), suggesting that 2F-Fuc is metabolically converted to the sugar nucleotide GDP-2F-Fuc, which serves as the active inhibitory molecule. The L-Fuc content of cell wall matrix polysaccharides was reduced in plants treated with 2F-Fuc, suggesting that this molecule inhibits the incorporation of L-Fuc into these polysaccharides. Additionally, phenotypic defects induced by 2F-Fuc treatment could be partially relieved by the exogenous application of boric acid, suggesting that 2F-Fuc inhibits RG-II biosynthesis. Overall, the results presented here suggest that 2F-Fuc is a metabolically incorporated inhibitor of plant cellular fucosylation events, and potentially suggest that other 2-fluorinated monosaccharides could serve as useful chemical probes for the inhibition of cell wall polysaccharide biosynthesis. PMID:26414071

Intracranial suprasellar angiolipoma: ultrastructural and immunohistochemical features.

PubMed

Lach, B; Lesiuk, H

1994-01-01

The authors present ultrastructural and immunohistochemical characteristics of an intracranial suprasellar tumor displaying features of cavernous angioma with islets of adipose tissue. Electron microscopy revealed thin-walled vessels separated by a loose collagenous stroma containing nests of mature adipocytes as well as fibroblasts, myofibroblasts, mast cells, and a few macrophages. Intracytoplasmic lipid droplets were also identified in scattered pericytes and smooth muscle cells of vascular walls and in the transitional cells resembling smooth muscle cells and adipocytes. Many adipose tissue cells were positive for S-100 protein with polyclonal antibodies. Other lipidized tumor cells were immunoreactive for some or all of the following: smooth muscle-specific actin, factor XIIIa, vimentin, and, occasionally, for desmin. Ultrastructure and immunohistochemistry indicate that in addition to typical adipocytes, lipidized cells of another nature contribute to the characteristic appearance of the adipose tissue component of angiolipoma.

Functional genomics of gam56: characterisation of the role of a 56 kilodalton sexual stage antigen in oocyst wall formation in Eimeria maxima.

PubMed

Belli, Sabina I; Witcombe, David; Wallach, Michael G; Smith, Nicholas C

2002-12-19

Gam56 (M(r) 56,000) is an antigen found in the sexual (macrogametocyte) stage of the intestinal parasite Eimeria maxima that is implicated in protective immunity. The gene (gam56) encoding this protein was cloned and sequenced. It is a single-copy, intronless gene, that localises to a 1,754 bp transcript, and is first detected at 120 h p.i. The gene predicts two distinct protein domains; a tyrosine-serine rich region, composed of amino acids implicated in oocyst wall formation in Eimeria spp., and a proline-methionine rich region often detected in extensins, protein components of plant cell walls. The tyrosine-serine rich region predicts a secondary structure commonly seen in the structural protein fibroin, a component of the cocoon of the caterpillar Bombyx mori. The inference that gam56 is a structural component of the oocyst wall was confirmed when a specific antibody to gam56 recognised the wall forming bodies in macrogametocytes, and the walls of oocysts and sporocysts. Together, these data identify a developmentally regulated, sexual stage gene in E. maxima that shares primary and secondary structure features in common with intrinsic structural proteins in other parasites such as Schistosoma mansoni and Fasciola hepatica, and other organisms across different phyla, including the caterpillar Bombyx mori. In addition, these findings provide evidence for the molecular mechanisms underlying oocyst wall formation in Eimeria and the role of gametocyte antigens in this process.

Wood cell-wall structure requires local 2D-microtubule disassembly by a novel plasma membrane-anchored protein.

PubMed

Oda, Yoshihisa; Iida, Yuki; Kondo, Yuki; Fukuda, Hiroo

2010-07-13

Plant cells have evolved cortical microtubules, in a two-dimensional space beneath the plasma membrane, that regulate patterning of cellulose deposition. Although recent studies have revealed that several microtubule-associated proteins facilitate self-organization of transverse cortical microtubules, it is still unknown how diverse patterns of cortical microtubules are organized in different xylem cells, which are the major components of wood. Using our newly established in vitro xylem cell differentiation system, we found that a novel microtubule end-tracking protein, microtubule depletion domain 1 (MIDD1), was anchored to distinct plasma membrane domains and promoted local microtubule disassembly, resulting in pits on xylem cell walls. The introduction of RNA interference for MIDD1 resulted in the failure of local microtubule depletion and the formation of secondary walls without pits. Conversely, the overexpression of MIDD1 reduced microtubule density. MIDD1 has two coiled-coil domains for the binding to microtubules and for the anchorage to plasma membrane domains, respectively. Combination of the two coils caused end tracking of microtubules during shrinkage and suppressed their rescue events. Our results indicate that MIDD1 integrates spatial information in the plasma membrane with cortical microtubule dynamics for determining xylem cell wall pattern. Copyright 2010 Elsevier Ltd. All rights reserved.

Disruption of non-anchored cell wall protein NCW-1 promotes cellulase production by increasing cellobiose uptake in Neurospora crassa.

PubMed

Lin, Liangcai; Chen, Yong; Li, Jingen; Wang, Shanshan; Sun, Wenliang; Tian, Chaoguang

2017-04-01

To elucidate the mechanism of cellulase signal transduction in filamentous fungi including the components of the cellulase induction pathway. Neurospora crassa ncw-1 encodes a non-anchored cell wall protein. The absence of ncw-1 increased cellulase gene expression and this is not due to relieving carbon catabolite repression mediated by the cre-1 pathway. A mutant lacking genes encoding both three major β-glucosidase enzymes and NCW-1 (Δ3βGΔncw-1) was constructed. Transcriptome analysis of the quadruple mutant demonstrated enhanced expression of cellodextrin transporters after ncw-1 deletion, indicating that ncw-1 affects cellulase expression and production by inhibiting the uptake of the cellodextrin. NCW-1 is a novel component that plays a critical role in the cellulase induction signaling pathway.

Laser selective microablation of sensitized intracellular components within auditory receptor cells

NASA Astrophysics Data System (ADS)

Harris, David M.; Evans, Burt N.; Santos-Sacchi, Joseph

1995-05-01

A laser system can be coupled to a light microscope for laser microbeam ablation and trapping of single cells in vitro. We have extended this technology by sensitization of target structures with vital dyes to provide selective ablation of specific subcellular components. Isolated auditory receptor cells (outer hair cells, OHCs) are known to elongate and contract in response to electrical, chemical and mechanical stimulation. Various intracellular structures are candidate components mediating motility of OHCs, but the exact mechanism(s) is currently unknown. In ongoing studies of OHC motility, we have used the microbeam for selective ablation of lateral wall components and of an axial cytoskeletal core that extends from the nucleus to the cell apex. Both the area beneath the subsurface cistemae of the lateral wall and the core are rich in mitochondria. OHCs isolated from guinea pig cochlea are suspended in L- 15 medium containing 2.0 (mu) M Rhodamine 123, a porphyrin with an affinity for mitochondria. A spark-pumped nitrogen laser pumping a dye cell (Coumarin 500) was aligned on the optical axis of a Nikon Optiphot-2 to produce a 3 ns, 0.5 - 10 micrometers spot (diameter above ablation threshold w/50X water immersion, N.A. 0.8), and energy at the target approximately equals 10 (mu) J/pulse. At short incubation times in Rh123 irradiation caused local blebbing or bulging of cytoplastic membrane and thus loss of the OHC's cylindrical shape. At longer Rh123 incubation times when the central axis of the cell was targeted we observed cytoplasmic clearing, immediate cell elongation (approximately equals 5%) and clumping of core material at nuclear and apical attachments. Experiments are underway to examine the significance of these preliminary observations.

Roles of the bacterial cell wall and capsule in induction of tumor necrosis factor alpha by type III group B streptococci.

PubMed Central

Vallejo, J G; Baker, C J; Edwards, M S

1996-01-01

Group B streptococci (GBS) are the major cause of sepsis and fatal shock in neonates in the United States. The precise role of tumor necrosis factor alpha (TNF-alpha) in the development of human GBS sepsis has not been defined; however, whole GBS have been shown to induce the production of this inflammatory cytokine. We sought to determine which bacterial cell wall components of GBS are responsible for triggering TNF-alpha production. Human cord blood monocytes were stimulated with encapsulated (COH1) or unencapsulated (COH1-13) whole type III GBS or with purified bacterial components, including type III capsular polysaccharide (III-PS), group B polysaccharide (GB-PS), lipoteichoic acid (LTA), or peptidoglycan (PG). Lipopolysaccharide from Escherichia coli served as a control. Supernatants were harvested at specific timed intervals, and TNF-alpha levels were measured by enzyme-linked immunosorbent assay. Monocytes exposed to COH1 and COH1-13 induced similar amounts of TNF-alpha. III-PS, GB-PS, LTA, and PG each induced TNF-alpha in a time- and concentration-dependent manner. However, TNF-alpha release was significantly greater after stimulation by the GB-PS or PG than after stimulation by III-PS or LTA (P < 0.05). Our findings indicate that GB-PS and PG are the bacterial cell wall components primarily evoking TNF-alpha release. These, alone or in concert with other factors, may be responsible for septic shock accompanying GBS sepsis. PMID:8945544

Naegleria fowleri: enolase is expressed during cyst differentiation.

PubMed

Chávez-Munguía, Bibiana; Segovia-Gamboa, Norma; Salazar-Villatoro, Lizbeth; Omaña-Molina, Maritza; Espinosa-Cantellano, Martha; Martínez-Palomo, Adolfo

2011-01-01

Cysts of Naegleria fowleri present an external single-layered cyst wall. To date, little information exists on the biochemical components of this cyst wall. Knowledge of the cyst wall composition is important to understand its resistance capacity under adverse environmental conditions. We have used of a monoclonal antibody (B4F2 mAb) that specifically recognizes enolase in the cyst wall of Entamoeba invadens. By Western blot assays this antibody recognized in soluble extracts of N. fowleri cysts a 48-kDa protein with similar molecular weight to the enolase reported in E. invadens cysts. Immunofluorescence with the B4F2 mAb revealed positive cytoplasmic vesicles in encysting amebas, as well as a positive reaction at the cell wall of mature cysts. Immunoelectron microscopy using the same monoclonal antibody confirmed the presence of enolase in the cell wall of N. fowleri cysts and in cytoplasmic vesicular structures. In addition, the B4F2 mAb had a clear inhibitory effect on encystation of N. fowleri. © 2011 The Author(s). Journal of Eukaryotic Microbiology © 2011 International Society of Protistologists.

Changes of wood cell walls in response to hygro-mechanical steam treatment.

PubMed

Guo, Juan; Song, Kunlin; Salmén, Lennart; Yin, Yafang

2015-01-22

The effects of compression combined with steam treatment (CS-treatment), i.e. a hygro-mechanical steam treatment on Spruce wood were studied on a cell-structure level to understand the chemical and physical changes of the secondary cell wall occurring under such conditions. Specially, imaging FT-IR microscopy, nanoindentation and dynamic vapour absorption were used to track changes in the chemical structure, in micromechanical and hygroscopic properties. It was shown that CS-treatment resulted in different changes in morphological, chemical and physical properties of the cell wall, in comparison with those under pure steam treatment. After CS-treatment, the cellular structure displayed significant deformations, and the biopolymer components, e.g. hemicellulose and lignin, were degraded, resulting in decreased hygroscopicity and increased mechanical properties of the wood compared to both untreated and steam treated wood. Moreover, CS-treatment resulted in a higher degree of degradation especially in earlywood compared to a more uniform behaviour of wood treated only by steam. Copyright © 2014 Elsevier Ltd. All rights reserved.

Multiscale Investigation from Subcellular to Tissue Scale of Onion Epidermal Plant Cell Wall Mechanical Properties

NASA Astrophysics Data System (ADS)

Zamil, Mohammad Shafayet

The physical and mechanical properties of cell walls, their shape, how they are arranged and interact with each other determine the architecture of plant organs and how they mechanically respond to different environmental and loading conditions. Due to the distinctive hierarchy from subcellular to tissue scale, plant materials can exhibit remarkably different mechanical properties. To date, how the subcellular scale arrangement and the mechanical properties of plant cell wall structural constituents give rise to macro or tissue scale mechanical responses is not yet well understood. Although the tissue scale plant cell wall samples are easy to prepare and put to different types of mechanical tests, the hierarchical features that emerge when moving towards a higher scale make it complicated to link the macro scale results to micro or subcellular scale structural components. On the other hand, the microscale size of cell brings formidable challenges to prepare and grip samples and carry mechanical tests under tensile loading at subcellular scale. This study attempted to develop a set of test protocols based on microelectromechanical system (MEMS) tensile testing devices for characterizing plant cell wall materials at different length scales. For the ease of sample preparation and well established database of the composition and conformation of its structural constituents, onion epidermal cell wall profile was chosen as the study material. Based on the results and findings of multiscale mechanical characterization, a framework of architecture-based finite element method (FEM) computational model was developed. The computational model laid the foundation of bridging the subcellular or microscale to the tissue or macroscale mechanical properties. This study suggests that there are important insights of cell wall mechanics and structural features that can only be investigated by carrying tensile characterization of samples not confounded by extracellular parameters. To the best of our knowledge, the plant cell wall at subcellular scale was never characterized under tensile loading. By coupling the structure based multiscale modeling and mechanical characterizations at different length scales, an attempt was made to provide novel insights towards understanding the mechanics and architecture of cell wall. This study also suggests that a multiscale investigation is essential for garnering fundamental insights into the hierarchical deformation of biological systems.

Processing of fullerene-single wall carbon nanotube complex for bulk heterojunction photovoltaic cells

NASA Astrophysics Data System (ADS)

Li, Cheng; Mitra, Somenath

2007-12-01

A fullerene-single wall carbon nanotube (C60-SWCNT) complex is used as a component of the photoactive layer in bulk heterojunction photovoltaic cells. This complex synthesized by microwave-assisted reaction takes advantage of the electron accepting feature of C60 and the high electron transport capability of SWCNTs. In this paper, quantum efficiency enhancement by increasing light absorption and by bringing about appropriate morphological rearrangements via solvent vapor treatment and thermal annealing is presented. The optimum combination of these steps led to an increase in efficiency by as much as 87.5%.

Cell wall proteins of Sporothrix schenckii as immunoprotective agents.

PubMed

Alba-Fierro, Carlos A; Pérez-Torres, Armando; López-Romero, Everardo; Cuéllar-Cruz, Mayra; Ruiz-Baca, Estela

2014-01-01

Sporothrix schenckii is the etiological agent of sporotrichosis, an endemic subcutaneous mycosis in Latin America. Cell wall (CW) proteins located on the cell surface are inducers of cellular and humoral immune responses, potential candidates for diagnosis purposes and to generate vaccines to prevent fungal infections. This mini-review emphasizes the potential use of S. schenckii CW proteins as protective and therapeutic immune response inducers against sporotrichosis. A number of pathogenic fungi display CW components that have been characterized as inducers of protective cellular and humoral immune responses against the whole pathogen from which they were originally purified. The isolation and characterization of immunodominant protein components of the CW of S. schenckii have become relevant because of their potential in the development of protective and therapeutic immune responses against sporotrichosis. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

Precision and sensitivity of the measurement of 15N enrichment in D-alanine from bacterial cell walls using positive/negative ion mass spectrometry

NASA Technical Reports Server (NTRS)

Tunlid, A.; Odham, G.; Findlay, R. H.; White, D. C.

1985-01-01

Sensitive detection of cellular components from specific groups of microbes can be utilized as 'signatures' in the examination of microbial consortia from soils, sediments or biofilms. Utilizing capillary gas chromatography/mass spectrometry and stereospecific derivatizing agents, D-alanine, a component localized in the prokaryotic (bacterial) cell wall, can be detected reproducibly. Enrichments of D-[15N]alanine determined in E. coli grown with [15N]ammonia can be determined with precision at 1.0 atom%. Chemical ionization with methane gas and the detection of negative ions (M - HF)- and (M - F or M + H - HF)- formed from the heptafluorobutyryl D-2 butanol ester of D-alanine allowed as little as 8 pg (90 fmol) to be detected reproducibly. This method can be utilized to define the metabolic activity in terms of 15N incorporation at the level of 10(3)-10(4) cells, as a function of the 15N-14N ratio.

Cellulose Synthesis and Its Regulation

PubMed Central

Li, Shundai; Bashline, Logan; Lei, Lei; Gu, Ying

2014-01-01

Cellulose, the most abundant biopolymer synthesized on land, is made of linear chains of ß (1–4) linked D-glucose. As a major structural component of the cell wall, cellulose is important not only for industrial use but also for plant growth and development. Cellulose microfibrils are tethered by other cell wall polysaccharides such as hemicellulose, pectin, and lignin. In higher plants, cellulose is synthesized by plasma membrane-localized rosette cellulose synthase complexes. Despite the recent advances using a combination of molecular genetics, live cell imaging, and spectroscopic tools, many aspects of the cellulose synthesis remain a mystery. In this chapter, we highlight recent research progress towards understanding the mechanism of cellulose synthesis in Arabidopsis. PMID:24465174

COBRA-LIKE2, a Member of the Glycosylphosphatidylinositol-Anchored COBRA-LIKE Family, Plays a Role in Cellulose Deposition in Arabidopsis Seed Coat Mucilage Secretory Cells1,2[OPEN

PubMed Central

Ben-Tov, Daniela; Abraham, Yael; Stav, Shira; Thompson, Kevin; Loraine, Ann; Elbaum, Rivka; de Souza, Amancio; Pauly, Markus; Kieber, Joseph J.; Harpaz-Saad, Smadar

2015-01-01

Differentiation of the maternally derived seed coat epidermal cells into mucilage secretory cells is a common adaptation in angiosperms. Recent studies identified cellulose as an important component of seed mucilage in various species. Cellulose is deposited as a set of rays that radiate from the seed upon mucilage extrusion, serving to anchor the pectic component of seed mucilage to the seed surface. Using transcriptome data encompassing the course of seed development, we identified COBRA-LIKE2 (COBL2), a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE gene family in Arabidopsis (Arabidopsis thaliana), as coexpressed with other genes involved in cellulose deposition in mucilage secretory cells. Disruption of the COBL2 gene results in substantial reduction in the rays of cellulose present in seed mucilage, along with an increased solubility of the pectic component of the mucilage. Light birefringence demonstrates a substantial decrease in crystalline cellulose deposition into the cellulosic rays of the cobl2 mutants. Moreover, crystalline cellulose deposition into the radial cell walls and the columella appears substantially compromised, as demonstrated by scanning electron microscopy and in situ quantification of light birefringence. Overall, the cobl2 mutants display about 40% reduction in whole-seed crystalline cellulose content compared with the wild type. These data establish that COBL2 plays a role in the deposition of crystalline cellulose into various secondary cell wall structures during seed coat epidermal cell differentiation. PMID:25583925

Chemical modification of wood

Treesearch

Roger M. Rowell

2005-01-01

The properties of any resource are, in general, a result of the chemistry of the components of that resource. In the case of wood, the cell wall polymers (cellulose, hemicelluloses, and lignin) are the components that, if modified, would change the properties of the resource. If the properties of the wood are modified, the performance of the modified wood would be...

A solution-state NMR approach to elucidating pMDI-wood bonding mechanisms in loblolly pine

Treesearch

Daniel Joseph Yelle

2009-01-01

Solution-state NMR spectroscopy is a powerful tool for unambiguously determining the existence or absence of covalent chemical bonds between wood components and adhesives. Finely ground wood cell wall material dissolves in a solvent system containing DMSO-d6 and NMI-d6, keeping wood component polymers intact and in a near-...

Bacterial components are the major contributors to the macrophage stimulating activity exhibited by extracts of common edible mushrooms

USDA-ARS?s Scientific Manuscript database

Background: Recent studies have indicated that a major contributor to the innate immune enhancing properties of some medicinal plants derive from the cell wall components of bacteria colonizing these plants. Purpose: The purpose of the current study was to assess if the bacteria present within edib...

Bacterial components are the major contributors to the macrophage stimulating activity exhibited by extracts of common edible mushrooms

USDA-ARS?s Scientific Manuscript database

Background: Recent studies have indicated that a major contributor to the innate immune enhancing properties of some medicinal plants is derived from the cell wall components of bacteria colonizing these plants. Purpose: The purpose of the current study was to assess if the bacteria present withi...

Characterization of Thermal and Mechanical Properties of Polypropylene-Based Composites for Fuel Cell Bipolar Plates and Development of Educational Tools in Hydrogen and Fuel Cell Technologies

ERIC Educational Resources Information Center

Lopez Gaxiola, Daniel

2011-01-01

In this project we developed conductive thermoplastic resins by adding varying amounts of three different carbon fillers: carbon black (CB), synthetic graphite (SG) and multi-walled carbon nanotubes (CNT) to a polypropylene matrix for application as fuel cell bipolar plates. This component of fuel cells provides mechanical support to the stack,…

Stimuli-responsive protamine-based biodegradable nanocapsules for enhanced bioavailability and intracellular delivery of anticancer agents

NASA Astrophysics Data System (ADS)

Radhakrishnan, Krishna; Thomas, Midhun B.; Pulakkat, Sreeranjini; Gnanadhas, Divya P.; Chakravortty, Dipshikha; Raichur, Ashok M.

2015-08-01

Enzyme- and pH-responsive polyelectrolyte nanocapsules having diameters in the range of 200 ± 20 nm were fabricated by means of Layer-by-Layer assembly of biopolymers, protamine, and heparin, and then loaded with anticancer drug doxorubicin. The incorporation of the FDA-approved peptide drug protamine as a wall component rendered the capsules responsive to enzyme stimuli. The stimuli-responsive drug release from these nanocapsules was evaluated, and further modulation of capsule permeability to avoid premature release was demonstrated by crosslinking the wall components. The interaction of the nanocapsules with cancer cells was studied using MCF-7 breast cancer cells. These capsules were readily internalized and disintegrated inside the cells, culminating in the release of the loaded doxorubicin and subsequent cell death as observed by confocal microscopy and MTT Assay. The bioavailability studies performed using BALB/c mice revealed that the encapsulated doxorubicin exhibited enhanced bioavailability compared to free doxorubicin. Our results indicate that this stimuli-responsive system fabricated from clinically used FDA-approved molecules and exhibiting minimal premature release has great potential for drug-delivery applications.

Histology and cell wall biochemistry of stone cells in the physical defence of conifers against insects.

PubMed

Whitehill, Justin G A; Henderson, Hannah; Schuetz, Mathias; Skyba, Oleksandr; Yuen, Macaire Man Saint; King, John; Samuels, A Lacey; Mansfield, Shawn D; Bohlmann, Jörg

2016-08-01

Conifers possess an array of physical and chemical defences against stem-boring insects. Stone cells provide a physical defence associated with resistance against bark beetles and weevils. In Sitka spruce (Picea sitchensis), abundance of stone cells in the cortex of apical shoots is positively correlated with resistance to white pine weevil (Pissodes strobi). We identified histological, biochemical and molecular differences in the stone cell phenotype of weevil resistant (R) or susceptible (S) Sitka spruce genotypes. R trees displayed significantly higher quantities of cortical stone cells near the apical shoot node, the primary site for weevil feeding. Lignin, cellulose, xylan and mannan were the most abundant components of stone cell secondary walls, respectively. Lignin composition of stone cells isolated from R trees contained a higher percentage of G-lignin compared with S trees. Transcript profiling revealed higher transcript abundance in the R genotype of coumarate 3-hydroxylase, a key monolignol biosynthetic gene. Developing stone cells in current year apical shoots incorporated fluorescent-tagged monolignol into the secondary cell wall, while mature stone cells of previous year apical shoots did not. Stone cell development is an ephemeral process, and fortification of shoot tips in R trees is an effective strategy against insect feeding. © 2015 John Wiley & Sons Ltd.

The impact of alterations in lignin deposition on cellulose organization of the plant cell wall

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jiliang; Kim, Jeong Im; Cusumano, Joanne C.

Background: Coordination of synthesis and assembly of the polymeric components of cell walls is essential for plant growth and development. Given the degree of co-mingling and cross-linking among cell wall components, cellulose organization must be dependent on the organization of other polymers such as lignin. Here we seek to identify aspects of that codependency by studying the structural organization of cellulose fibrils in stems from Arabidopsis plants harboring mutations in genes encoding enzymes involved in lignin biosynthesis. Plants containing high levels of G-lignin, S-lignin, H-lignin, aldehyde-rich lignin, and ferulic acid-containing lignin, along with plants with very low lignin content weremore » grown and harvested and longitudinal sections of stem were prepared and dried. Scanning X-ray microdiffraction was carried out using a 5-micron beam that moved across the sections in 5-micron steps and complete diffraction patterns were collected at each raster point. Approximately, 16,000 diffraction patterns were analyzed to determine cellulose fibril orientation and order within the tissues making up the stems. Results: Several mutations-most notably those exhibiting (1) down-regulation of cinnamoyl CoA reductase which leads to cell walls deficient in lignin and (2) defect of cinnamic acid 4-hydroxylase which greatly reduces lignin content-exhibited significant decrease in the proportion of oriented cellulose fibrils in the cell wall. Distinctions between tissues were maintained in all variants and even in plants exhibiting dramatic changes in cellulosic order the trends between tissues (where apparent) were generally maintained. The resilience of cellulose to degradative processes was investigated by carrying out the same analysis on samples stored in water for 30 days prior to data collection. This treatment led to significant loss of cellulosic order in plants rich in aldehyde or H-lignin, less change in wild type, and essentially no change in samples with high levels of G-or S-lignin. Conclusions: These studies demonstrate that changes in lignin biosynthesis lead to significant disruption in the orientation and order of cellulose fibrils in all tissues of the stem. These dramatic phenotypic changes, in mutants with lignin rich in aldehyde or H-units, correlate with the impact the mutations have on the enzymatic degradation of the plant cell wall.« less

Redox Control of Aphid Resistance through Altered Cell Wall Composition and Nutritional Quality1[OPEN

PubMed Central

Rasool, Brwa; Marcus, Sue E.

2017-01-01

The mechanisms underpinning plant perception of phloem-feeding insects, particularly aphids, remain poorly characterized. Therefore, the role of apoplastic redox state in controlling aphid infestation was explored using transgenic tobacco (Nicotiana tabacum) plants that have either high (PAO) or low (TAO) ascorbate oxidase (AO) activities relative to the wild type. Only a small number of leaf transcripts and metabolites were changed in response to genotype, and cell wall composition was largely unaffected. Aphid fecundity was decreased significantly in TAO plants compared with other lines. Leaf sugar levels were increased and maximum extractable AO activities were decreased in response to aphids in all genotypes. Transcripts encoding the Respiratory Burst Oxidase Homolog F, signaling components involved in ethylene and other hormone-mediated pathways, photosynthetic electron transport components, sugar, amino acid, and cell wall metabolism, were increased significantly in the TAO plants in response to aphid perception relative to other lines. The levels of galactosylated xyloglucan were decreased significantly in response to aphid feeding in all the lines, the effect being the least in the TAO plants. Similarly, all lines exhibited increases in tightly bound (1→4)-β-galactan. Taken together, these findings identify AO-dependent mechanisms that limit aphid infestation. PMID:28743764

Raman Imaging of Plant Cell Walls in Sections of Cucumis sativus

PubMed Central

Zeise, Ingrid; Heiner, Zsuzsanna; Holz, Sabine; Joester, Maike; Büttner, Carmen

2018-01-01

Raman microspectra combine information on chemical composition of plant tissues with spatial information. The contributions from the building blocks of the cell walls in the Raman spectra of plant tissues can vary in the microscopic sub-structures of the tissue. Here, we discuss the analysis of 55 Raman maps of root, stem, and leaf tissues of Cucumis sativus, using different spectral contributions from cellulose and lignin in both univariate and multivariate imaging methods. Imaging based on hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicates different substructures in the xylem cell walls of the different tissues. Using specific signals from the cell wall spectra, analysis of the whole set of different tissue sections based on the Raman images reveals differences in xylem tissue morphology. Due to the specifics of excitation of the Raman spectra in the visible wavelength range (532 nm), which is, e.g., in resonance with carotenoid species, effects of photobleaching and the possibility of exploiting depletion difference spectra for molecular characterization in Raman imaging of plants are discussed. The reported results provide both, specific information on the molecular composition of cucumber tissue Raman spectra, and general directions for future imaging studies in plant tissues. PMID:29370089

Raman Imaging of Plant Cell Walls in Sections of Cucumis sativus.

PubMed

Zeise, Ingrid; Heiner, Zsuzsanna; Holz, Sabine; Joester, Maike; Büttner, Carmen; Kneipp, Janina

2018-01-25

Raman microspectra combine information on chemical composition of plant tissues with spatial information. The contributions from the building blocks of the cell walls in the Raman spectra of plant tissues can vary in the microscopic sub-structures of the tissue. Here, we discuss the analysis of 55 Raman maps of root, stem, and leaf tissues of Cucumis sativus , using different spectral contributions from cellulose and lignin in both univariate and multivariate imaging methods. Imaging based on hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicates different substructures in the xylem cell walls of the different tissues. Using specific signals from the cell wall spectra, analysis of the whole set of different tissue sections based on the Raman images reveals differences in xylem tissue morphology. Due to the specifics of excitation of the Raman spectra in the visible wavelength range (532 nm), which is, e.g., in resonance with carotenoid species, effects of photobleaching and the possibility of exploiting depletion difference spectra for molecular characterization in Raman imaging of plants are discussed. The reported results provide both, specific information on the molecular composition of cucumber tissue Raman spectra, and general directions for future imaging studies in plant tissues.

Beta-lactamase induction and cell wall metabolism in Gram-negative bacteria

PubMed Central

Zeng, Ximin; Lin, Jun

2013-01-01

Production of beta-lactamases, the enzymes that degrade beta-lactam antibiotics, is the most widespread and threatening mechanism of antibiotic resistance. In the past, extensive research has focused on the structure, function, and ecology of beta-lactamases while limited efforts were placed on the regulatory mechanisms of beta-lactamases. Recently, increasing evidence demonstrate a direct link between beta-lactamase induction and cell wall metabolism in Gram-negative bacteria. Specifically, expression of beta-lactamase could be induced by the liberated murein fragments, such as muropeptides. This article summarizes current knowledge on cell wall metabolism, beta-lactam antibiotics, and beta-lactamases. In particular, we comprehensively reviewed recent studies on the beta-lactamase induction by muropeptides via two major molecular mechanisms (the AmpG–AmpR–AmpC pathway and BlrAB-like two-component regulatory system) in Gram-negative bacteria. The signaling pathways for beta-lactamase induction offer a broad array of promising targets for the discovery of new antibacterial drugs used for combination therapies. Therefore, to develop effective mitigation strategies against the widespread beta-lactam resistance, examination of the molecular basis of beta-lactamase induction by cell wall fragment is highly warranted. PMID:23734147

The inside and outside: topological issues in plant cell wall biosynthesis and the roles of nucleotide sugar transporters.

PubMed

Temple, Henry; Saez-Aguayo, Susana; Reyes, Francisca C; Orellana, Ariel

2016-09-01

The cell wall is a complex extracellular matrix composed primarily of polysaccharides. Noncellulosic polysaccharides, glycoproteins and proteoglycans are synthesized in the Golgi apparatus by glycosyltransferases (GTs), which use nucleotide sugars as donors to glycosylate nascent glycan and glycoprotein acceptors that are subsequently exported to the extracellular space. Many nucleotide sugars are synthesized in the cytosol, leading to a topological issue because the active sites of most GTs are located in the Golgi lumen. Nucleotide sugar transporters (NSTs) overcome this problem by translocating nucleoside diphosphate sugars from the cytosol into the lumen of the organelle. The structures of the cell wall components synthesized in the Golgi are diverse and complex; therefore, transporter activities are necessary so that the nucleotide sugars can provide substrates for the GTs. In this review, we describe the topology of reactions involved in polysaccharide biosynthesis in the Golgi and focus on the roles of NSTs as well as their impacts on cell wall structure when they are altered. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Lipoteichoic acids are embedded in cell walls during logarithmic phase, but exposed on membrane vesicles in Lactobacillus gasseri JCM 1131T.

PubMed

Shiraishi, T; Yokota, S; Sato, Y; Ito, T; Fukiya, S; Yamamoto, S; Sato, T; Yokota, A

2018-06-15

Lipoteichoic acid (LTA) is a cell surface molecule specific to Gram-positive bacteria. How LTA localises on the cell surface is a fundamental issue in view of recognition and immunomodulation in hosts. In the present study, we examined LTA localisation using strain JCM 1131T of Lactobacillus gasseri, which is a human intestinal lactic acid bacterium, during various growth phases by immunoelectron microscopy. We first evaluated the specificity of anti-LTA monoclonal antibody clone 55 used as a probe. The glycerophosphate backbone comprising almost intact size (20 to 30 repeating units) of LTA was required for binding. The antibody did not bind to other cellular components, including wall-teichoic acid. Immunoelectron microscopy indicated that LTA was embedded in the cell wall during the logarithmic phase, and was therefore not exposed on the cell surface. Similar results were observed for Lactobacillus fermentum ATCC 9338 and Lactobacillus rhamnosus ATCC 7469T. By contrast, membrane vesicles were observed in the logarithmic phase of L. gasseri with LTA exposed on their surface. In the stationary and death phases, LTA was exposed on cell wall-free cell membrane generated by autolysis. The dramatic alternation of localisation in different growth phases and exposure on the surface of membrane vesicles should relate with complicated interaction between bacteria and host.

Contribution of vascular cell-derived cytokines to innate and inflammatory pathways in atherogenesis

PubMed Central

Loppnow, Harald; Buerke, Michael; Werdan, Karl; Rose-John, Stefan

2011-01-01

Abstract Inflammation is a central element of atherogenesis. Innate pathways contribute to vascular inflammation. However, the initial molecular process(es) starting atherogenesis remain elusive. The various risk factors, represented by particular compounds (activators), may cause altered cellular functions in the endothelium (e.g. vascular endothelial cell activation or -dysfunction), in invading cells (e.g. inflammatory mediator production) or in local vessel wall cells (e.g. inflammatory mediators, migration), thereby triggering the innate inflammatory process. The cellular components of innate immunology include granulocytes, natural killer cells and monocytes. Among the molecular innate constituents are innate molecules, such as the toll-like receptors or innate cytokines. Interleukin-1 (IL-1) and IL-6 are among the innate cytokines. Cytokines are potent activators of a great number of cellular functions relevant to maintain or commove homeostasis of the vessel wall. Within the vessel wall, vascular smooth muscle cells (SMCs) can significantly contribute to the cytokine-dependent inflammatory network by: (i) production of cytokines, (ii) response to cytokines and (iii) cytokine-mediated interaction with invading leucocytes. The cytokines IL-1 and IL-6 are involved in SMC-leucocyte interaction. The IL-6 effects are proposed to be mediated by trans-signalling. Dysregulated cellular functions resulting from dysregulated cytokine production may be the cause of cell accumulation, subsequent low-density lipoprotein accumulation and deposition of extracellular matrix (ECM). The deposition of ECM, increased accumulation of leucocytes and altered levels of inflammatory mediators may constitute an ‘innate-immunovascular-memory’ resulting in an ever-growing response to anew invasion. Thus, SMC-fostered inflammation, promoted by invading innate cells, may be a potent component for development and acceleration of atherosclerosis. PMID:21199323

Effects of biaxial oscillatory shear stress on endothelial cell proliferation and morphology.

PubMed

Chakraborty, Amlan; Chakraborty, Sutirtha; Jala, Venkatakrishna R; Haribabu, Bodduluri; Sharp, M Keith; Berson, R Eric

2012-03-01

Wall shear stress (WSS) on anchored cells affects their responses, including cell proliferation and morphology. In this study, the effects of the directionality of pulsatile WSS on endothelial cell proliferation and morphology were investigated for cells grown in a Petri dish orbiting on a shaker platform. Time and location dependent WSS was determined by computational fluid dynamics (CFD). At low orbital speed (50 rpm), WSS was shown to be uniform (0-1 dyne/cm(2)) across the bottom of the dish, while at higher orbital speed (100 and 150 rpm), WSS remained fairly uniform near the center and fluctuated significantly (0-9 dyne/cm(2)) near the side walls of the dish. Since WSS on the bottom of the dish is two-dimensional, a new directional oscillatory shear index (DOSI) was developed to quantify the directionality of oscillating shear. DOSI approached zero for biaxial oscillatory shear of equal magnitudes near the center and approached one for uniaxial pulsatile shear near the wall, where large tangential WSS dominated a much smaller radial component. Near the center (low DOSI), more, smaller and less elongated cells grew, whereas larger cells with greater elongation were observed in the more uniaxial oscillatory shear (high DOSI) near the periphery of the dish. Further, cells aligned with the direction of the largest component of shear but were randomly oriented in low magnitude biaxial shear. Statistical analyses of the individual and interacting effects of multiple factors (DOSI, shear magnitudes and orbital speeds) showed that DOSI significantly affected all the responses, indicating that directionality is an important determinant of cellular responses. Copyright © 2011 Wiley Periodicals, Inc.

The vomeronasal organ of the cat.

PubMed Central

Salazar, I; Sanchez Quinteiro, P; Cifuentes, J M; Garcia Caballero, T

1996-01-01

The vomeronasal organ of the cat was studied macroscopically, by light microscopy and by immunohistochemical techniques. Special attention was paid to the general distribution of the various soft tissue components of this organ (duct, glands, connective tissue, blood vessels and nerves.) Examination of series of transverse sections showed that the wall of the vomeronasal duct bears 44 different types of epithelium: simple columnar in the caudal part of the duct, respiratory and receptor respectively on the lateral and medial walls of the middle part of the duct, and stratified squamous rostrally. The pattern of distribution of other soft tissue components was closely associated with that of epithelium types. In areas where the duct wall was lined with receptor epithelium, nerves and connective tissue were present between the epithelium and the medial sheet of the vomeronasal cartilage. Most glands and blood vessels were located lateral to those areas of the duct wall lined with respiratory epithelium. Numerous basal cells were present in the sensory epithelium. Understanding of the distribution of the soft tissue components of this organ may shed light on its function. Images Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Figs. 13-14 PMID:8621344

Aspen pectate lyase PtxtPL1-27 mobilizes matrix polysaccharides from woody tissues and improves saccharification yield

PubMed Central

2014-01-01

Background Wood cell walls are rich in cellulose, hemicellulose and lignin. Hence, they are important sources of renewable biomass for producing energy and green chemicals. However, extracting desired constituents from wood efficiently poses significant challenges because these polymers are highly cross-linked in cell walls and are not easily accessible to enzymes and chemicals. Results We show that aspen pectate lyase PL1-27, which degrades homogalacturonan and is expressed at the onset of secondary wall formation, can increase the solubility of wood matrix polysaccharides. Overexpression of this enzyme in aspen increased solubility of not only pectins but also xylans and other hemicelluloses, indicating that homogalacturonan limits the solubility of major wood cell wall components. Enzymatic saccharification of wood obtained from PL1-27-overexpressing trees gave higher yields of pentoses and hexoses than similar treatment of wood from wild-type trees, even after acid pretreatment. Conclusions Thus, the modification of pectins may constitute an important biotechnological target for improved wood processing despite their low abundance in woody biomass. PMID:24450583

A clade in the QUASIMODO2 family evolved with vascular plants and supports a role for cell wall composition in adaptation to environmental changes.

PubMed

Fuentes, Sara; Pires, Nuno; Østergaard, Lars

2010-08-01

The evolution of plant vascular tissue is tightly linked to the evolution of specialised cell walls. Mutations in the QUASIMODO2 (QUA2) gene from Arabidopsis thaliana were previously shown to result in cell adhesion defects due to reduced levels of the cell wall component homogalacturonic acid. In this study, we provide additional information about the role of QUA2 and its closest paralogues, QUASIMODO2 LIKE1 (QUL1) and QUL2. Within the extensive QUA2 family, our phylogenetic analysis shows that these three genes form a clade that evolved with vascular plants. Consistent with a possible role of this clade in vasculature development, QUA2 is highly expressed in the vascular tissue of embryos and inflorescence stems and overexpression of QUA2 resulted in temperature-sensitive xylem collapse. Moreover, in-depth characterisation of qua2 qul1 qul2 triple mutant and 35S::QUA2 overexpression plants revealed contrasting temperature-dependent stem development with dramatic effects on stem width. Taken together, our results suggest that the QUA2-specific clade contributed to the evolution of vasculature and illustrate the important role that modification of cell wall composition plays in the adaptation to changing environmental conditions, including changes in temperature.

Genetic and environmental factors contribute to variation in cell wall composition in mature desi chickpea (Cicer arietinum L.) cotyledons.

PubMed

Wood, Jennifer A; Tan, Hwei-Ting; Collins, Helen M; Yap, Kuok; Khor, Shi Fang; Lim, Wai Li; Xing, Xiaohui; Bulone, Vincent; Burton, Rachel A; Fincher, Geoffrey B; Tucker, Matthew R

2018-03-13

Chickpea (Cicer arietinum L.) is an important nutritionally rich legume crop that is consumed worldwide. Prior to cooking, desi chickpea seeds are most often dehulled and cleaved to release the split cotyledons, referred to as dhal. Compositional variation between desi genotypes has a significant impact on nutritional quality and downstream processing, and this has been investigated mainly in terms of starch and protein content. Studies in pulses such as bean and lupin have also implicated cell wall polysaccharides in cooking time variation, but the underlying relationship between desi chickpea cotyledon composition and cooking performance remains unclear. Here, we utilized a variety of chemical and immunohistological assays to examine details of polysaccharide composition, structure, abundance, and location within the desi chickpea cotyledon. Pectic polysaccharides were the most abundant cell wall components, and differences in monosaccharide and glycosidic linkage content suggest both environmental and genetic factors contribute to cotyledon composition. Genotype-specific differences were identified in arabinan structure, pectin methylesterification, and calcium-mediated pectin dimerization. These differences were replicated in distinct field sites and suggest a potentially important role for cell wall polysaccharides and their underlying regulatory machinery in the control of cooking time in chickpea. © 2018 The Authors. Plant, Cell & Environment Published by John Wiley & Sons Ltd.

Expression, purification, crystallization and preliminary X-ray diffraction analysis of an essential lipoprotein implicated in cell-wall biosynthesis in Mycobacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marland, Zara; Beddoe, Travis; Zaker-Tabrizi, Leyla

2005-12-01

A lipoprotein implicated in mycobacterial cell-wall biosynthesis, LpqW, was expressed in E. coli. Crystals were obtained that diffracted to 2.4 Å resolution. Mycobacterium tuberculosis is a renewed cause of devastation in the developing world. Critical to the success of this re-emerging pathogen is its unusual waxy cell wall, which is rich in rare components including lipoarabinomannan (LAM) and its precursors, the phosphatidylinositol mannosides (PIMs). Balanced synthesis of these related glycolipids is intrinsic to both cell-wall integrity and virulence in M. tuberculosis and presents a promising, albeit poorly defined, therapeutic target. Here, the expression, purification and crystallization of an essential 600-amino-acidmore » lipoprotein, LpqW, implicated in this process are reported. Crystals of LpqW were grown using 20–24%(w/v) PEG 4000, 8–16%(v/v) 2-propanol, 100 mM sodium citrate pH 5.5 and 10 mM DTT. A complete data set was collected at 2.4 Å using synchrotron radiation on a crystal belonging to space group C222, with unit-cell parameters a = 188.57, b = 312.04, c = 104.15 Å. Structure determination is under way.« less

Genetically Engineered Materials for Biofuels Production

NASA Astrophysics Data System (ADS)

Raab, Michael

2012-02-01

Agrivida, Inc., is an agricultural biotechnology company developing industrial crop feedstocks for the fuel and chemical industries. Agrivida's crops have improved processing traits that enable efficient, low cost conversion of the crops' cellulosic components into fermentable sugars. Currently, pretreatment and enzymatic conversion of the major cell wall components, cellulose and hemicellulose, into fermentable sugars is the most expensive processing step that prevents widespread adoption of biomass in biofuels processes. To lower production costs we are consolidating pretreatment and enzyme production within the crop. In this strategy, transgenic plants express engineered cell wall degrading enzymes in an inactive form, which can be reactivated after harvest. We have engineered protein elements that disrupt enzyme activity during normal plant growth. Upon exposure to specific processing conditions, the engineered enzymes are converted into their active forms. This mechanism significantly lowers pretreatment costs and enzyme loadings (>75% reduction) below those currently available to the industry.

SEM study of the effects of bacteria and yeasts on wood decay by brown and white-rot fungi. [Enterobacter, Cryptococcus Pichia, and Saccharomyces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchette, R.A.; Shaw, C.G.; Cohen, A.L.

The scanning electron microscope was used to 1) examine the associations among microorganisms during wood decay and 2) observe the effect of these organisms on degradation of cell wall components. Bacteria (Enterobacter) and yeasts (Cryptococcus Pichia, and Saccharomyces) were found to have a mutualistic association with a white-rot fungus during decay of coniferous wood. Coriolus (Polyporus versicolar) degraded cell wall components in a typical ''erosion trough'' manner (i.e., by lysing zones around fungal hyphae). Bacteria and yeasts were seen only in these lysed zones. Typical gross decay patterns caused by the white-rot fungus were unaltered by bacteria and yeasts. Themore » SEM study suggests that the decay process is enhanced when these organisms are associated. In contrast, the same bacteria and yeasts were inhibitory when combined with a brown-rot fungus.« less

Bacterial Cell Mechanics.

PubMed

Auer, George K; Weibel, Douglas B

2017-07-25

Cellular mechanical properties play an integral role in bacterial survival and adaptation. Historically, the bacterial cell wall and, in particular, the layer of polymeric material called the peptidoglycan were the elements to which cell mechanics could be primarily attributed. Disrupting the biochemical machinery that assembles the peptidoglycan (e.g., using the β-lactam family of antibiotics) alters the structure of this material, leads to mechanical defects, and results in cell lysis. Decades after the discovery of peptidoglycan-synthesizing enzymes, the mechanisms that underlie their positioning and regulation are still not entirely understood. In addition, recent evidence suggests a diverse group of other biochemical elements influence bacterial cell mechanics, may be regulated by new cellular mechanisms, and may be triggered in different environmental contexts to enable cell adaptation and survival. This review summarizes the contributions that different biomolecular components of the cell wall (e.g., lipopolysaccharides, wall and lipoteichoic acids, lipid bilayers, peptidoglycan, and proteins) make to Gram-negative and Gram-positive bacterial cell mechanics. We discuss the contribution of individual proteins and macromolecular complexes in cell mechanics and the tools that make it possible to quantitatively decipher the biochemical machinery that contributes to bacterial cell mechanics. Advances in this area may provide insight into new biology and influence the development of antibacterial chemotherapies.

Interactions between lipids and proteins are critical for organization of plasma membrane-ordered domains in tobacco BY-2 cells.

PubMed

Grosjean, Kevin; Der, Christophe; Robert, Franck; Thomas, Dominique; Mongrand, Sébastien; Simon-Plas, Françoise; Gerbeau-Pissot, Patricia

2018-06-27

The laterally heterogeneous plant plasma membrane (PM) is organized into finely controlled specialized areas that include membrane-ordered domains. Recently, the spatial distribution of such domains within the PM has been identified as playing a key role in cell responses to environmental challenges. To examine membrane order at a local level, BY-2 tobacco suspension cell PMs were labelled with an environment-sensitive probe (di-4-ANEPPDHQ). Four experimental models were compared to identify mechanisms and cell components involved in short-term (1 h) maintenance of the ordered domain organization in steady-state cell PMs: modulation of the cytoskeleton or the cell wall integrity of tobacco BY-2 cells; and formation of giant vesicles using either a lipid mixture of tobacco BY-2 cell PMs or the original lipid and protein combinations of the tobacco BY-2 cell PM. Whilst inhibiting phosphorylation or disrupting either the cytoskeleton or the cell wall had no observable effects, we found that lipids and proteins significantly modified both the abundance and spatial distribution of ordered domains. This indicates the involvement of intrinsic membrane components in the local physical state of the plant PM. Our findings support a major role for the 'lipid raft' model, defined as the sterol-dependent ordered assemblies of specific lipids and proteins in plant PM organization.

Thermal protection apparatus

DOEpatents

Bennett, Gloria A.; Moore, Troy K.

1988-01-01

An apparatus for thermally protecting heat sensitive components of tools. The apparatus comprises a Dewar for holding the heat sensitive components. The Dewar has spaced-apart inside and outside walls, an open top end and a bottom end. An insulating plug is located in the top end. The inside wall has portions defining an inside wall aperture located at the bottom of the Dewar and the outside wall has portions defining an outside wall aperture located at the bottom of the Dewar. A bottom connector has inside and outside components. The inside component sealably engages the inside wall aperture and the outside component sealably engages the outside wall aperture. The inside component is operatively connected to the heat sensitive components and to the outside component. The connections can be made with optical fibers or with electrically conducting wires.

Advances in the genetic dissection of plant cell walls: tools and resources available in Miscanthus

PubMed Central

Slavov, Gancho; Allison, Gordon; Bosch, Maurice

2013-01-01

Tropical C4 grasses from the genus Miscanthus are believed to have great potential as biomass crops. However, Miscanthus species are essentially undomesticated, and genetic, molecular and bioinformatics tools are in very early stages of development. Furthermore, similar to other crops targeted as lignocellulosic feedstocks, the efficient utilization of biomass is hampered by our limited knowledge of the structural organization of the plant cell wall and the underlying genetic components that control this organization. The Institute of Biological, Environmental and Rural Sciences (IBERS) has assembled an extensive collection of germplasm for several species of Miscanthus. In addition, an integrated, multidisciplinary research programme at IBERS aims to inform accelerated breeding for biomass productivity and composition, while also generating fundamental knowledge. Here we review recent advances with respect to the genetic characterization of the cell wall in Miscanthus. First, we present a summary of recent and on-going biochemical studies, including prospects and limitations for the development of powerful phenotyping approaches. Second, we review current knowledge about genetic variation for cell wall characteristics of Miscanthus and illustrate how phenotypic data, combined with high-density arrays of single-nucleotide polymorphisms, are being used in genome-wide association studies to generate testable hypotheses and guide biological discovery. Finally, we provide an overview of the current knowledge about the molecular biology of cell wall biosynthesis in Miscanthus and closely related grasses, discuss the key conceptual and technological bottlenecks, and outline the short-term prospects for progress in this field. PMID:23847628

Nitrogen fertilizer application affects lodging resistance by altering secondary cell wall synthesis in japonica rice (Oryza sativa).

PubMed

Zhang, Wujun; Wu, Longmei; Ding, Yanfeng; Yao, Xiong; Wu, Xiaoran; Weng, Fei; Li, Ganghua; Liu, Zhenghui; Tang, She; Ding, Chengqiang; Wang, Shaohua

2017-09-01

Stem mechanical strength is an important agricultural quantitative trait that is closely related to lodging resistance in rice, which is known to be reduced by fertilizer with higher levels of nitrogen. To understand the mechanism that regulates stem mechanical strength in response to nitrogen, we analysed stem morphology, anatomy, mechanical properties, cell wall components, and expression of cell wall-related genes, in two varieties of japonica rice, namely, Wuyunjing23 (lodging-resistant variety) and W3668 (lodging-susceptible variety). The results showed that higher nitrogen fertilizer increased the lodging index in both varieties due to a reduction in breaking strength and bending stress, and these changes were larger in W3668. Cellulose content decreased slightly under higher nitrogen fertilizer, whereas lignin content reduced remarkably. Histochemical staining revealed that high nitrogen application decreased lignin deposition in the secondary cell wall of the sclerenchyma cells and vascular bundle cells compared with the low nitrogen treatments, while it did not alter the pattern of cellulose deposition in these cells in both Wuyunjing23 and W3668. In addition, the expression of the genes involved in lignin biosynthesis, OsPAL, OsCoMT, Os4CL3, OsCCR, OsCAD2, OsCAD7, OsCesA4, and OsCesA7, were also down-regulated under higher nitrogen conditions at the early stage of culm growth. These results suggest that the genes involved in lignin biosynthesis are down-regulated by higher nitrogen fertilizer, which causes lignin deficiency in the secondary cell walls and the weakening of mechanical tissue structure. Subsequently, this results in these internodes with reduced mechanical strength and poor lodging resistance.

Mycobacterial biofilms: a greasy way to hold it together.

PubMed

Zambrano, María Mercedes; Kolter, Roberto

2005-12-02

Microorganisms growing on surfaces can form biofilms under certain conditions. In this issue of Cell, Ojha et al. (2005) investigate biofilm formation in mycobacteria. They identify new cell-wall components that are required for the formation of architecturally complex mature biofilms in these bacteria and the surprising involvement of a chaperone protein in this process.

An Arabidopsis lipid flippase is required for timely recruitment of defenses to the host-pathogen interface at the plant cell surface

USDA-ARS?s Scientific Manuscript database

Deposition of cell wall-reinforcing papillae is an integral component of the plant immune response. The Arabidopsis PENETRATION 3 (PEN3) ATP binding cassette (ABC) transporter plays a role in defense against numerous pathogens and is recruited to sites of pathogen detection where it accumulates with...

Impact of bacteria and bacterial components on osteogenic and adipogenic differentiation of adipose-derived mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiedler, Tomas, E-mail: tomas.fiedler@med.uni-rostock.de; Salamon, Achim; Adam, Stefanie

Adult mesenchymal stem cells (MSC) are present in several tissues, e.g. bone marrow, heart muscle, brain and subcutaneous adipose tissue. In invasive infections MSC get in contact with bacteria and bacterial components. Not much is known about how bacterial pathogens interact with MSC and how contact to bacteria influences MSC viability and differentiation potential. In this study we investigated the impact of three different wound infection relevant bacteria, Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes, and the cell wall components lipopolysaccharide (LPS; Gram-negative bacteria) and lipoteichoic acid (LTA; Gram-positive bacteria) on viability, proliferation, and osteogenic as well as adipogenic differentiationmore » of human adipose tissue-derived mesenchymal stem cells (adMSC). We show that all three tested species were able to attach to and internalize into adMSC. The heat-inactivated Gram-negative E. coli as well as LPS were able to induce proliferation and osteogenic differentiation but reduce adipogenic differentiation of adMSC. Conspicuously, the heat-inactivated Gram-positive species showed the same effects on proliferation and adipogenic differentiation, while its cell wall component LTA exhibited no significant impact on adMSC. Therefore, our data demonstrate that osteogenic and adipogenic differentiation of adMSC is influenced in an oppositional fashion by bacterial antigens and that MSC-governed regeneration is not necessarily reduced under infectious conditions. - Highlights: • Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli bind to and internalize into adMSC. • Heat-inactivated cells of these bacterial species trigger proliferation of adMSC. • Heat-inactivated E. coli and LPS induce osteogenic differentiation of adMSC. • Heat-inactivated E. coli and LPS reduce adipogenic differentiation of adMSC. • LTA does not influence adipogenic or osteogenic differentiation of adMSC.« less

The role of heat shock proteins in protection and pathophysiology of the arterial wall.

PubMed

Xu, Q; Wick, G

1996-09-01

The arterial wall is an integrated functional component of the circulatory system that is continually remodelling in response to various stressors, including localized injury, toxins, smoking and hypercholesterolaemia. These stimuli directly or indirectly cause changes in blood pressure and damage to the vessel wall, and eventually induce arterial stiffness and obstruction. To maintain the homeostasis of the vessel wall, the vascular cells produce a high level of stress proteins, also known as heat shock proteins, which protect against damage during haemodynamic stress. However, an immune reaction to heat shock proteins might contribute to the development of atherosclerosis. We hypothesize that the induction of heat shock proteins is beneficial in the arterial wall's response to stress but is harmful in certain other circumstances.

Accumulation and localization of extensin protein in apoplast of pea root nodule under aluminum stress.

PubMed

Sujkowska-Rybkowska, Marzena; Borucki, Wojciech

2014-12-01

Cell wall components such as hydroxyproline-rich glycoproteins (HRGPs, extensins) have been proposed to be involved in aluminum (Al) resistance mechanisms in plants. We have characterized the distribution of extensin in pea (Pisum sativum L.) root nodules apoplast under short (for 2 and 24h) Al stress. Monoclonal antibodie LM1 have been used to locate extensin protein epitope by immunofluorescence and immunogold labeling. The nodules were shown to respond to Al stress by thickening of plant and infection thread (IT) walls and disturbances in threads growth and bacteria endocytosis. Immunoblot results indicated the presence of a 17-kDa band specific for LM1. Irrespective of the time of Al stress, extensin content increased in root nodules. Further observation utilizing fluorescence and transmission electron microscope showed that LM1 epitope was localized in walls and intercellular spaces of nodule cortex tissues and in the infection threads matrix. Al stress in nodules appears to be associated with higher extensin accumulation in matrix of enlarged thick-walled ITs. In addition to ITs, thickened walls and intercellular spaces of nodule cortex were also associated with intense extensin accumulation. These data suggest that Al-induced extensin accumulation in plant cell walls and ITs matrix may have influence on the process of IT growth and tissue and cell colonization by Rhizobium bacteria. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rim Pathway-Mediated Alterations in the Fungal Cell Wall Influence Immune Recognition and Inflammation.

PubMed

Ost, Kyla S; Esher, Shannon K; Leopold Wager, Chrissy M; Walker, Louise; Wagener, Jeanette; Munro, Carol; Wormley, Floyd L; Alspaugh, J Andrew

2017-01-31

Compared to other fungal pathogens, Cryptococcus neoformans is particularly adept at avoiding detection by innate immune cells. To explore fungal cellular features involved in immune avoidance, we characterized cell surface changes of the C. neoformans rim101Δ mutant, a strain that fails to organize and shield immunogenic epitopes from host detection. These cell surface changes are associated with an exaggerated, detrimental inflammatory response in mouse models of infection. We determined that the disorganized strain rim101Δ cell wall increases macrophage detection in a contact-dependent manner. Using biochemical and microscopy methods, we demonstrated that the rim101Δ strain shows a modest increase in the levels of both cell wall chitin and chitosan but that it shows a more dramatic increase in chito-oligomer exposure, as measured by wheat germ agglutinin staining. We also created a series of mutants with various levels of cell wall wheat germ agglutinin staining, and we demonstrated that the staining intensity correlates with the degree of macrophage activation in response to each strain. To explore the host receptors responsible for recognizing the rim101Δ mutant, we determined that both the MyD88 and CARD9 innate immune signaling proteins are involved. Finally, we characterized the immune response to the rim101Δ mutant in vivo, documenting a dramatic and sustained increase in Th1 and Th17 cytokine responses. These results suggest that the Rim101 transcription factor actively regulates the C. neoformans cell wall to prevent the exposure of immune stimulatory molecules within the host. These studies further explored the ways in which immune cells detect C. neoformans and other fungal pathogens by mechanisms that include sensing N-acetylglucosamine-containing structures, such as chitin and chitosan. Infectious microorganisms have developed many ways to avoid recognition by the host immune system. For example, pathogenic fungi alter their cell surfaces to mask immunogenic epitopes. We have created a fungal strain with a targeted mutation in a pH response pathway that is unable to properly organize its cell wall, resulting in a dramatic immune reaction during infection. This mutant cell wall is defective in hiding important cell wall components, such as the chito-oligomers chitin and chitosan. By creating a series of cell wall mutants, we demonstrated that the degree of chito-oligomer exposure correlates with the intensity of innate immune cell activation. This activation requires a combination of host receptors to recognize and respond to these infecting microorganisms. Therefore, these experiments explored host-pathogen interactions that determine the degree of the subsequent inflammatory response and the likely outcome of infection. Copyright © 2017 Ost et al.

Optically Transparent Wood from a Nanoporous Cellulosic Template: Combining Functional and Structural Performance.

PubMed

Li, Yuanyuan; Fu, Qiliang; Yu, Shun; Yan, Min; Berglund, Lars

2016-04-11

Optically transparent wood (TW) with transmittance as high as 85% and haze of 71% was obtained using a delignified nanoporous wood template. The template was prepared by removing the light-absorbing lignin component, creating nanoporosity in the wood cell wall. Transparent wood was prepared by successful impregnation of lumen and the nanoscale cellulose fiber network in the cell wall with refractive-index-matched prepolymerized methyl methacrylate (MMA). During the process, the hierarchical wood structure was preserved. Optical properties of TW are tunable by changing the cellulose volume fraction. The synergy between wood and PMMA was observed for mechanical properties. Lightweight and strong transparent wood is a potential candidate for lightweight low-cost, light-transmitting buildings and transparent solar cell windows.

Adhesion, invasion and evasion: the many functions of the surface proteins of Staphylococcus aureus

PubMed Central

Foster, Timothy J.; Geoghegan, Joan A.; Ganesh, Vannakambadi K.; Höök, Magnus

2014-01-01

Staphylococcus aureus is an important opportunistic pathogen and persistently colonizes about 20% of the human population. Its surface is ‘decorated’ with proteins that are covalently anchored to the cell wall peptidoglycan. Structural and functional analysis has identified four distinct classes of surface proteins, of which microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) are the largest class. These surface proteins have numerous functions, including adhesion to and invasion of host cells and tissues, evasion of immune responses and biofilm formation. Thus, cell wall-anchored proteins are essential virulence factors for the survival of S. aureus in the commensal state and during invasive infections, and targeting them with vaccines could combat S. aureus infections. PMID:24336184

Defined tetra-allelic gene disruption of the 4-coumarate:coenzyme A ligase 1 (Pv4CL1) gene by CRISPR/Cas9 in switchgrass results in lignin reduction and improved sugar release

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Jong -Jin; Yoo, Chang Geun; Flanagan, Amy

The development of genome editing technologies offers new prospects in improving bioenergy crops like switchgrass (Panicum virgatum). Switchgrass is an outcrossing species with an allotetraploid genome (2n = 4x = 36), a complexity which forms an impediment to generating homozygous knock-out plants. Lignin, a major component of the plant cell wall and a contributor to cellulosic feedstock’s recalcitrance to decomposition, stands as a barrier to efficient biofuel production by limiting enzyme access to cell wall polymers during the fermentation process.

Defined tetra-allelic gene disruption of the 4-coumarate:coenzyme A ligase 1 (Pv4CL1) gene by CRISPR/Cas9 in switchgrass results in lignin reduction and improved sugar release

DOE PAGES

Park, Jong -Jin; Yoo, Chang Geun; Flanagan, Amy; ...

2017-11-30

The development of genome editing technologies offers new prospects in improving bioenergy crops like switchgrass (Panicum virgatum). Switchgrass is an outcrossing species with an allotetraploid genome (2n = 4x = 36), a complexity which forms an impediment to generating homozygous knock-out plants. Lignin, a major component of the plant cell wall and a contributor to cellulosic feedstock’s recalcitrance to decomposition, stands as a barrier to efficient biofuel production by limiting enzyme access to cell wall polymers during the fermentation process.

COBRA-LIKE2, a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE family, plays a role in cellulose deposition in arabidopsis seed coat mucilage secretory cells.

PubMed

Ben-Tov, Daniela; Abraham, Yael; Stav, Shira; Thompson, Kevin; Loraine, Ann; Elbaum, Rivka; de Souza, Amancio; Pauly, Markus; Kieber, Joseph J; Harpaz-Saad, Smadar

2015-03-01

Differentiation of the maternally derived seed coat epidermal cells into mucilage secretory cells is a common adaptation in angiosperms. Recent studies identified cellulose as an important component of seed mucilage in various species. Cellulose is deposited as a set of rays that radiate from the seed upon mucilage extrusion, serving to anchor the pectic component of seed mucilage to the seed surface. Using transcriptome data encompassing the course of seed development, we identified COBRA-LIKE2 (COBL2), a member of the glycosylphosphatidylinositol-anchored COBRA-LIKE gene family in Arabidopsis (Arabidopsis thaliana), as coexpressed with other genes involved in cellulose deposition in mucilage secretory cells. Disruption of the COBL2 gene results in substantial reduction in the rays of cellulose present in seed mucilage, along with an increased solubility of the pectic component of the mucilage. Light birefringence demonstrates a substantial decrease in crystalline cellulose deposition into the cellulosic rays of the cobl2 mutants. Moreover, crystalline cellulose deposition into the radial cell walls and the columella appears substantially compromised, as demonstrated by scanning electron microscopy and in situ quantification of light birefringence. Overall, the cobl2 mutants display about 40% reduction in whole-seed crystalline cellulose content compared with the wild type. These data establish that COBL2 plays a role in the deposition of crystalline cellulose into various secondary cell wall structures during seed coat epidermal cell differentiation. © 2015 American Society of Plant Biologists. All Rights Reserved.

Pectin methylesterase31 positively regulates salt stress tolerance in Arabidopsis.

PubMed

Yan, Jingwei; He, Huan; Fang, Lin; Zhang, Aying

2018-02-05

The alteration of cell wall component and structure is an important adaption to saline environment. Pectins, a major cell wall component, are often present in a highly methylesterified form. The level of methyl esterification determined by pectin methylesterases (PMEs) influences many important wall properties that are believed to relate to the adaption to saline stress. However, little is known about the function of PMEs in response to salt stress. Here, we established a link between pectin methylesterase31 (PME31) and salt stress tolerance. Salt stress significantly increases PME31 expression. PME31 is located in the plasma membrane and the expression level of PME31 was high in dry seeds. Knock-down mutants in PME31 conferred hypersensitive phenotypes to salt stress in seed germination and post-germination growth. Real-time PCR analysis revealed that the transcript levels of several stress genes (DREB2A, RD29A and RD29B) are lower in pme31-2 mutant than that in the wild type in response to salt stress. These results suggested that PME31 could positively modulate salt stress tolerance. Copyright © 2018 Elsevier Inc. All rights reserved.

A novel role of the ferric reductase Cfl1 in cell wall integrity, mitochondrial function, and invasion to host cells in Candida albicans.

PubMed

Yu, Qilin; Dong, Yijie; Xu, Ning; Qian, Kefan; Chen, Yulu; Zhang, Biao; Xing, Laijun; Li, Mingchun

2014-11-01

Candida albicans is an important opportunistic pathogen, causing both superficial mucosal infections and life-threatening systemic diseases. Iron acquisition is an important factor for pathogen-host interaction and also a significant element for the pathogenicity of this organism. Ferric reductases, which convert ferric iron into ferrous iron, are important components of the high-affinity iron uptake system. Sequence analyses have identified at least 17 putative ferric reductase genes in C. albicans genome. CFL1 was the first ferric reductase identified in C. albicans. However, little is known about its roles in C. albicans physiology and pathogenicity. In this study, we found that disruption of CFL1 led to hypersensitivity to chemical and physical cell wall stresses, activation of the cell wall integrity (CWI) pathway, abnormal cell wall composition, and enhanced secretion, indicating a defect in CWI in this mutant. Moreover, this mutant showed abnormal mitochondrial activity and morphology, suggesting a link between ferric reductases and mitochondrial function. In addition, this mutant displayed decreased ability of adhesion to both the polystyrene microplates and buccal epithelial cells and invasion of host epithelial cells. These findings revealed a novel role of C. albicans Cfl1 in maintenance of CWI, mitochondrial function, and interaction between this pathogen and the host. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

β(1,3)-Glucanosyl-Transferase Activity Is Essential for Cell Wall Integrity and Viability of Schizosaccharomyces pombe

PubMed Central

de Medina-Redondo, María; Arnáiz-Pita, Yolanda; Clavaud, Cécile; Fontaine, Thierry; del Rey, Francisco; Latgé, Jean Paul; Vázquez de Aldana, Carlos R.

2010-01-01

Background The formation of the cell wall in Schizosaccharomyces pombe requires the coordinated activity of enzymes involved in the biosynthesis and modification of β-glucans. The β(1,3)-glucan synthase complex synthesizes linear β(1,3)-glucans, which remain unorganized until they are cross-linked to other β(1,3)-glucans and other cell wall components. Transferases of the GH72 family play important roles in cell wall assembly and its rearrangement in Saccharomyces cerevisiae and Aspergillus fumigatus. Four genes encoding β(1,3)-glucanosyl-transferases -gas1+, gas2+, gas4+ and gas5+- are present in S. pombe, although their function has not been analyzed. Methodology/Principal Findings Here, we report the characterization of the catalytic activity of gas1p, gas2p and gas5p together with studies directed to understand their function during vegetative growth. From the functional point of view, gas1p is essential for cell integrity and viability during vegetative growth, since gas1Δ mutants can only grow in osmotically supported media, while gas2p and gas5p play a minor role in cell wall construction. From the biochemical point of view, all of them display β(1,3)-glucanosyl-transferase activity, although they differ in their specificity for substrate length, cleavage point and product size. In light of all the above, together with the differences in expression profiles during the life cycle, the S. pombe GH72 proteins may accomplish complementary, non-overlapping functions in fission yeast. Conclusions/Significance We conclude that β(1,3)-glucanosyl-transferase activity is essential for viability in fission yeast, being required to maintain cell integrity during vegetative growth. PMID:21124977

The Fusarium oxysporum gnt2, Encoding a Putative N-Acetylglucosamine Transferase, Is Involved in Cell Wall Architecture and Virulence

PubMed Central

López-Fernández, Loida; Ruiz-Roldán, Carmen; Pareja-Jaime, Yolanda; Prieto, Alicia; Khraiwesh, Husam; Roncero, M. Isabel G.

2013-01-01

With the aim to decipher the molecular dialogue and cross talk between Fusarium oxysporum f.sp. lycopersci and its host during infection and to understand the molecular bases that govern fungal pathogenicity, we analysed genes presumably encoding N-acetylglucosaminyl transferases, involved in glycosylation of glycoproteins, glycolipids, proteoglycans or small molecule acceptors in other microorganisms. In silico analysis revealed the existence of seven putative N-glycosyl transferase encoding genes (named gnt) in F. oxysporum f.sp. lycopersici genome. gnt2 deletion mutants showed a dramatic reduction in virulence on both plant and animal hosts. Δgnt2 mutants had αalterations in cell wall properties related to terminal αor β-linked N-acetyl glucosamine. Mutant conidia and germlings also showed differences in structure and physicochemical surface properties. Conidial and hyphal aggregation differed between the mutant and wild type strains, in a pH independent manner. Transmission electron micrographs of germlings showed strong cell-to-cell adherence and the presence of an extracellular chemical matrix. Δgnt2 cell walls presented a significant reduction in N-linked oligosaccharides, suggesting the involvement of Gnt2 in N-glycosylation of cell wall proteins. Gnt2 was localized in Golgi-like sub-cellular compartments as determined by fluorescence microscopy of GFP::Gnt2 fusion protein after treatment with the antibiotic brefeldin A or by staining with fluorescent sphingolipid BODIPY-TR ceramide. Furthermore, density gradient ultracentrifugation allowed co-localization of GFP::Gnt2 fusion protein and Vps10p in subcellular fractions enriched in Golgi specific enzymatic activities. Our results suggest that N-acetylglucosaminyl transferases are key components for cell wall structure and influence interactions of F. oxysporum with both plant and animal hosts during pathogenicity. PMID:24416097

Hermetically sealed electrical feedthrough for high temperature secondary cells

DOEpatents

Knoedler, R.; Nelson, P.A.; Shimotake, H.; Battles, J.E.

1983-07-26

A passthrough seal is disclosed for electrically isolating the terminal in a lithium/metal sulfide cell from the structural cell housing. The seal has spaced upper and lower insulator rings fitted snuggly between the terminal and an annularly disposed upstanding wall, and outwardly of a powdered insulator also confined between the upstanding wall and terminal. The adjacent surfaces of the upper insulator ring and the respective upstanding wall and terminal are conically tapered, diverging in the axial direction away from the cell interior, and a sealing ring is located between each pair of the adjacent surfaces. The components are sized so that upon appropriate movement of the upper insulator ring toward the lower insulator ring the powdered insulator and sealing rings are each compressed to a high degree. This compacts the powdered insulator thereby rendering the same highly impervious and moreover fuses the sealing rings to and between the adjacent surfaces. The upper and lower insulator rings might be formed of beryllium oxide and/or alumina, the powdered insulator might be formed of boron nitride, and the sealing rings might be formed of aluminum.

Anatomy and cell wall polysaccharides of almond (Prunus dulcis D. A. Webb) seeds.

PubMed

Dourado, Fernando; Barros, António; Mota, Manuel; Coimbra, Manuel A; Gama, Francisco M

2004-03-10

The anatomy of Prunus dulcis was analyzed by applying several differential staining techniques and light microscopy. Prunus dulcis seed has a thin and structurally complex seed coat, with lignified cellulosic tissue. The embryo has two voluminous cotyledons. Cotyledon cells have a high number of protein and lipid bodies, some of which have phytin. The provascular tissue, located in the cotyledons, is oriented in small bundles perpendicular to the transverse embryonic axis. Prunus dulcis cell wall material is very rich in arabinose (45 mol %). Glucose (23%), uronic acids (12%), and xylose (12%) are also major sugar components. The polymers obtained from the imidazole and Na(2)CO(3) extracts contain mainly pectic substances rich in arabinose, but the sugar content of these extracts was very low. The majority of the pectic substances (also rich in arabinose) was recovered with the KOH extracts. These extracts, with high sugar content, yielded also xyloglucans and acidic xylans. The 4 M KOH + H(3)BO(3) extracts yielded polysaccharides rich in uronic acids and xylose and very rich in arabinose, accounting for 27% of the cell wall material.

The Bacillus subtilis GntR family repressor YtrA responds to cell wall antibiotics.

PubMed

Salzberg, Letal I; Luo, Yun; Hachmann, Anna-Barbara; Mascher, Thorsten; Helmann, John D

2011-10-01

The transglycosylation step of cell wall synthesis is a prime antibiotic target because it is essential and specific to bacteria. Two antibiotics, ramoplanin and moenomycin, target this step by binding to the substrate lipid II and the transglycosylase enzyme, respectively. Here, we compare the ramoplanin and moenomycin stimulons in the Gram-positive model organism Bacillus subtilis. Ramoplanin strongly induces the LiaRS two-component regulatory system, while moenomycin almost exclusively induces genes that are part of the regulon of the extracytoplasmic function (ECF) σ factor σ(M). Ramoplanin additionally induces the ytrABCDEF and ywoBCD operons, which are not part of a previously characterized antibiotic-responsive regulon. Cluster analysis reveals that these two operons are selectively induced by a subset of cell wall antibiotics that inhibit lipid II function or recycling. Repression of both operons requires YtrA, which recognizes an inverted repeat in front of its own operon and in front of ywoB. These results suggest that YtrA is an additional regulator of cell envelope stress responses.

The Bacillus subtilis GntR Family Repressor YtrA Responds to Cell Wall Antibiotics▿§

PubMed Central

Salzberg, Letal I.; Luo, Yun; Hachmann, Anna-Barbara; Mascher, Thorsten; Helmann, John D.

2011-01-01

The transglycosylation step of cell wall synthesis is a prime antibiotic target because it is essential and specific to bacteria. Two antibiotics, ramoplanin and moenomycin, target this step by binding to the substrate lipid II and the transglycosylase enzyme, respectively. Here, we compare the ramoplanin and moenomycin stimulons in the Gram-positive model organism Bacillus subtilis. Ramoplanin strongly induces the LiaRS two-component regulatory system, while moenomycin almost exclusively induces genes that are part of the regulon of the extracytoplasmic function (ECF) σ factor σM. Ramoplanin additionally induces the ytrABCDEF and ywoBCD operons, which are not part of a previously characterized antibiotic-responsive regulon. Cluster analysis reveals that these two operons are selectively induced by a subset of cell wall antibiotics that inhibit lipid II function or recycling. Repression of both operons requires YtrA, which recognizes an inverted repeat in front of its own operon and in front of ywoB. These results suggest that YtrA is an additional regulator of cell envelope stress responses. PMID:21856850

Inhomogeneity of Cellulose Microfibril Assembly in Plant Cell Walls Revealed with Sum Frequency Generation Microscopy.

PubMed

Huang, Shixin; Makarem, Mohamadamin; Kiemle, Sarah N; Hamedi, Hossein; Sau, Moujhuri; Cosgrove, Daniel J; Kim, Seong H

2018-05-17

Sum frequency generation (SFG) vibrational spectroscopy can selectively detect and analyze noncentrosymmetric components interspersed in amorphous matrices; this principle has been used for studies of nanoscale structure and mesoscale assembly of cellulose in plant cell walls. However, the spectral information averaged over a large area or volume cannot provide regiospecific or tissue-specific information of different cells in plants. This study demonstrates spatially resolved SFG analysis and imaging by combining a broad-band SFG spectroscopy system with an optical microscope. The system was designed to irradiate both narrow-band 800 nm and broad-band tunable IR beams through a single reflective objective lens, but from opposite sides of the surface normal direction of the sample. The developed technique was used to reveal inhomogeneous distributions of cellulose microfibrils within single cell walls, such as cotton fibers and onion epidermis as well as among different tissues in Arabidopsis inflorescence stems and bamboo culms. SFG microscopy can be used for vibrational spectroscopic imaging of other biological systems in complement to conventional Fourier transform infrared spectroscopy and confocal Raman microscopy.

Hermetically sealed electrical feedthrough for high temperature secondary cells

DOEpatents

Knoedler, Reinhard; Nelson, Paul A.; Shimotake, Hiroshi; Battles, James E.

1985-01-01

A passthrough seal is disclosed for electrically isolating the terminal in a lithium/metal sulfide cell from the structural cell housing. The seal has spaced upper and lower insulator rings fitted snuggly between the terminal and an annularly disposed upstanding wall, and outwardly of a powdered insulator also confined between the upstanding wall and terminal. The adjacent surfaces of the upper insulator ring and the respective upstanding wall and terminal are conically tapered, diverging in the axial direction away from the cell interior, and a sealing ring is located between each pair of the adjacent surfaces. The components are sized so that upon appropriate movement of the upper insulator ring toward the lower insulator ring the powdered insulator and sealing rings are each compressed to a high degree. This compacts the powdered insulator thereby rendering the same highly impervious and moreover fuses the sealing rings to and between the adjacent surfaces. The upper and lower insulator rings might be formed of beryllium oxide and/or alumina, the powdered insulator might be formed of boron nitride, and the sealing rings might be formed of aluminum.

Exploiting fungal cell wall components in vaccines.

PubMed

Levitz, Stuart M; Huang, Haibin; Ostroff, Gary R; Specht, Charles A

2015-03-01

Innate recognition of fungi leads to strong adaptive immunity. Investigators are trying to exploit this observation in vaccine development by combining antigens with evolutionarily conserved fungal cell wall carbohydrates to induce protective responses. Best studied is β-1,3-glucan, a glycan that activates complement and is recognized by dectin-1. Administration of antigens in association with β-1,3-glucan, either by direct conjugation or complexed in glucan particles, results in robust humoral and cellular immune responses. While the host has a host of mannose receptors, responses to fungal mannoproteins generally are amplified if cells are cooperatively stimulated with an additional danger signal such as a toll-like receptor agonist. Chitosan, a polycationic homopolymer of glucosamine manufactured by the deacetylation of chitin, is being studied as an adjuvant in DNA and protein-based vaccines. It appears particularly promising in mucosal vaccines. Finally, universal and organism-specific fungal vaccines have been formulated by conjugating fungal cell wall glycans to carrier proteins. A major challenge will be to advance these experimental findings so that at risk patients can be protected.

Exploiting fungal cell wall components in vaccines

PubMed Central

Levitz, Stuart M.; Huang, Haibin; Ostroff, Gary R.; Specht, Charles A.

2014-01-01

Innate recognition of fungi leads to strong adaptive immunity. Investigators are trying to exploit this observation in vaccine development by combining antigens with evolutionarily conserved fungal cell wall carbohydrates to induce protective responses. Best studied is β-1,3-glucan, a glycan that activates complement and is recognized by Dectin-1. Administration of antigens in association with β-1,3-glucan, either by direct conjugation or complexed in glucan particles, results in robust humoral and cellular immune responses. While the host has a host of mannose receptors, responses to fungal mannoproteins generally are amplified if cells are cooperatively stimulated with an additional danger signal such as a toll-like receptor agonist. Chitosan, a polycationic homopolymer of glucosamine manufactured by the deacetylation of chitin, is being studied as an adjuvant in DNA and protein-based vaccines. It appears particularly promising in mucosal vaccines. Finally, universal and organism-specific fungal vaccines have been formulated by conjugating fungal cell wall glycans to carrier proteins. A major challenge will be to advance these experimental findings so that at risk patients can be protected. PMID:25404118

The configuration of 2,6-diamino-3-hydroxypimelic acid in microbial cell walls

PubMed Central

Perkins, H. R.

1969-01-01

β-Hydroxydiaminopimelic acid, together with some diaminopimelic acid, occurs in the cell-wall mucopeptide of certain Actinomycetales. These components were converted into their di-DNP derivatives and separated by chromatography. Hence the relative proportions present in the cell walls of a number of species were measured. The problem of acid-induced inversion of configuration was studied. Of the diaminohydroxypimelic acids isomer B (see Scheme 2; amino groups meso, hydroxy group threo to its neighbouring amino group) always predominated but a small proportion of isomer D (amino groups l, hydroxy group erythro) also occurred. The configuration of the diaminohydroxypimelic acids was determined by periodate oxidation to glutamic γ-semialdehyde, which underwent spontaneous ring-closure. Reduction with sodium borohydride produced optically active proline, the configuration of which was determined by direct measurement of the optical rotation of DNP-proline. Un-cross-linked diaminohydroxypimelic acid in the cell wall was oxidized with periodate in the presence of ammonia. Since the remaining amino group was bound in peptide linkage, ring-closure was prevented and borohydride reduction of the aldehyde–ammonia presumed to be present resulted in the formation of ornithine. The quantity of ornithine was used as a measure of the degree of cross-linking. PMID:4311441

Production by Tobacco Transplastomic Plants of Recombinant Fungal and Bacterial Cell-Wall Degrading Enzymes to Be Used for Cellulosic Biomass Saccharification.

PubMed

Longoni, Paolo; Leelavathi, Sadhu; Doria, Enrico; Reddy, Vanga Siva; Cella, Rino

2015-01-01

Biofuels from renewable plant biomass are gaining momentum due to climate change related to atmospheric CO2 increase. However, the production cost of enzymes required for cellulosic biomass saccharification is a major limiting step in this process. Low-cost production of large amounts of recombinant enzymes by transgenic plants was proposed as an alternative to the conventional microbial based fermentation. A number of studies have shown that chloroplast-based gene expression offers several advantages over nuclear transformation due to efficient transcription and translation systems and high copy number of the transgene. In this study, we expressed in tobacco chloroplasts microbial genes encoding five cellulases and a polygalacturonase. Leaf extracts containing the recombinant enzymes showed the ability to degrade various cell-wall components under different conditions, singly and in combinations. In addition, our group also tested a previously described thermostable xylanase in combination with a cellulase and a polygalacturonase to study the cumulative effect on the depolymerization of a complex plant substrate. Our results demonstrate the feasibility of using transplastomic tobacco leaf extracts to convert cell-wall polysaccharides into reducing sugars, fulfilling a major prerequisite of large scale availability of a variety of cell-wall degrading enzymes for biofuel industry.

Analysis of Complex Carbohydrate Composition in Plant Cell Wall Using Fourier Transformed Mid-Infrared Spectroscopy (FT-IR).

PubMed

Badhan, Ajay; Wang, Yuxi; McAllister, Tim A

2017-01-01

Fourier transformed mid-infrared spectroscopy (FTIR) is a powerful tool for compositional analysis of plant cell walls (Acebes et al., Front Plant Sci 5:303, 2014; Badhan et al., Biotechnol Biofuels 7:1-15, 2014; Badhan et al., BioMed Res Int 2015: 562952, 2015; Roach et al., Plant Physiol 156:1351-1363, 2011). The infrared spectrum generates a fingerprint of a sample with absorption peaks corresponding to the frequency of vibrations between the bonds of the atoms making up the material. Here, we describe a method focused on the use of FTIR in combination with principal component analysis (PCA) to characterize the composition of the plant cell wall. This method has been successfully used to study complex enzyme saccharification processes like rumen digestion to identify recalcitrant moieties in low-quality forage which resist rumen digestion (Badhan et al., BioMed Res Int 2015: 562952, 2015), as well as to characterize cell wall mutant lines or transgenic lines expressing exogenous hydrolases (Badhan et al., Biotechnol Biofuels 7:1-15, 2014; Roach et al., Plant Physiol 156:1351-1363, 2011). The FTIR method described here facilitates high-throughput identification of the major compositional differences across a large set of samples in a low cost and nondestructive manner.

Innate signaling by mycobacterial cell wall components and relevance for development of adjuvants for subunit vaccines.

PubMed

Tima, Hermann Giresse; Huygen, Kris; Romano, Marta

2016-11-01

Pathogen recognition receptors (PRRs) recognize pathogen-associated molecular patterns, triggering the induction of inflammatory innate responses and contributing to the development of specific adaptive immune responses. Novel adjuvants have been developed based on agonists of PRRs. Areas covered: Lipid pathogen-associated molecular patterns (PAMPs) present in the cell wall of mycobacteria are revised, with emphasis on agonists of C-type lectin receptors, signaling pathways, and preclinical data supporting their use as novel adjuvants inducing cell-mediated immune responses. Their potential use as lipid antigens in novel tuberculosis subunit vaccines is also discussed. Expert commentary: Few adjuvants are licensed for human use and mainly favour antibody-mediated protective immunity. Use of lipid PAMPs that trigger cell-mediated immune responses could lead to the development of adjuvants for vaccines against intracellular pathogens and cancer.

From microgravity to osmotic conditions: mechanical integration of plant cells in response to stress

NASA Astrophysics Data System (ADS)

Wojtaszek, Przemyslaw; Kasprowicz, Anna; Michalak, Michal; Janczara, Renata; Volkmann, Dieter; Baluska, Frantisek

Chemical reactions and interactions between molecules are commonly thought of as being at the basis of Life. Research of recent years, however, is more and more evidently indicating that physical forces are profoundly affecting the functioning of life at all levels of its organiza-tion. To detect and to respond to such forces, plant cells need to be integrated mechanically. Cell walls are the outermost functional zone of plant cells. They surround the individual cells, and also form a part of the apoplast. In cell suspensions, cell walls are embedded in the cul-ture medium which can be considered as a superapoplast. Through physical and chemical interactions they provide a basis for the structural and functional cell wall-plasma membrane-cytoskeleton (WMC) continuum spanning the whole cell. Here, the working of WMC contin-uum, and the participation of signalling molecules, like NO, would be presented in the context of plant responses to stress. In addition, the effects of the changing composition of WMC continuum will be considered, with particular attention paid to the modifications of the WMC components. Plant cells are normally adapted to changing osmotic conditions, resulting from variable wa-ter availability. The appearance of the osmotic stress activates adaptory mechanisms. If the strength of osmotic stress grows relatively slowly over longer period of time, the cells are able to adapt to conditions that are lethal to non-adapted cells. During stepwise adaptation of tobacco BY-2 suspension cells to the presence of various osmotically active agents, cells diverged into independent, osmoticum type-specific lines. In response to ionic agents (NaCl, KCl), the adhe-sive properties were increased and randomly dividing cells formed clumps, while cells adapted to nonionic osmotica (mannitol, sorbitol, PEG) revealed ordered pattern of precisely positioned cell divisions, resulting in the formation of long cell files. Changes in the growth patterns were accompanied by the alterations in the composition of wall proteins and polysaccharides. With respect to the cytoskeleton, in cells exposed to short-term osmotic stress significant rearrange-ments were observed. Surprisingly, the analyses of microfilaments and microtubules in adapted and in non-adapted, normal BY-2 cells, revealed no significant changes. It seems that upon prolonged exposure to osmotic stress conditions selective and adaptive alterations in wall com-position were occurring. Walls of cells grown in the presence of ionic agents were homogenous, while longitudinal walls and cross-walls in cells adapted to nonionic agents were significantly different. This might affect the anchorage of the cytoskeleton in the walls and modify the func-tioning of the whole WMC continuum. In this way, cell's mechanical balance restoration will be ensured and, in consequence, cells will be able to resist osmotic pressure and divide under severe stress conditions. In plants, cross-walls within cell files of axial organs exhibit specific properties that allow them to act as domains of contact and intense intercellular communica-tion, and the sites of the anchorage of cytoskeleton. As a further consequence, also cell-to-cell interactions would be affected. MM and RJ are students of biotechnology at Adam Mickiewicz University. The data coming from the authors' lab come from research supported by the DAAD scholarship to AK, and Alexander von Humboldt Research Fellowship and Polish Ministry of Science and Higher Edu-cation grants PBZ-KBN-110/P04/2004, N N303 294434, N N301 164435, and N N303 360735 to PW.

The Ser/Thr Protein Kinase Protein-Protein Interaction Map of M. tuberculosis.

PubMed

Wu, Fan-Lin; Liu, Yin; Jiang, He-Wei; Luan, Yi-Zhao; Zhang, Hai-Nan; He, Xiang; Xu, Zhao-Wei; Hou, Jing-Li; Ji, Li-Yun; Xie, Zhi; Czajkowsky, Daniel M; Yan, Wei; Deng, Jiao-Yu; Bi, Li-Jun; Zhang, Xian-En; Tao, Sheng-Ce

2017-08-01

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, the leading cause of death among all infectious diseases. There are 11 eukaryotic-like serine/threonine protein kinases (STPKs) in Mtb, which are thought to play pivotal roles in cell growth, signal transduction and pathogenesis. However, their underlying mechanisms of action remain largely uncharacterized. In this study, using a Mtb proteome microarray, we have globally identified the binding proteins in Mtb for all of the STPKs, and constructed the first STPK protein interaction (KPI) map that includes 492 binding proteins and 1,027 interactions. Bioinformatics analysis showed that the interacting proteins reflect diverse functions, including roles in two-component system, transcription, protein degradation, and cell wall integrity. Functional investigations confirmed that PknG regulates cell wall integrity through key components of peptidoglycan (PG) biosynthesis, e.g. MurC. The global STPK-KPIs network constructed here is expected to serve as a rich resource for understanding the key signaling pathways in Mtb, thus facilitating drug development and effective control of Mtb. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Interference of the Histone Deacetylase Inhibits Pollen Germination and Pollen Tube Growth in Picea wilsonii Mast

PubMed Central

Zhou, Junhui; Li, Xiaojuan

2015-01-01

Histone deacetylase (HDAC) is a crucial component in the regulation of gene expression in various cellular processes in animal and plant cells. HDAC has been reported to play a role in embryogenesis. However, the effect of HDAC on androgamete development remains unclear, especially in gymnosperms. In this study, we used the HDAC inhibitors trichostatin A (TSA) and sodium butyrate (NaB) to examine the role of HDAC in Picea wilsonii pollen germination and pollen tube elongation. Measurements of the tip-focused Ca2+ gradient revealed that TSA and NaB influenced this gradient. Immunofluorescence showed that actin filaments were disrupted into disorganized fragments. As a result, the vesicle trafficking was disturbed, as determined by FM4-64 labeling. Moreover, the distribution of pectins and callose in cell walls was significantly altered in response to TSA and NaB. Our results suggest that HDAC affects pollen germination and polarized pollen tube growth in Picea wilsonii by affecting the intracellular Ca2+ concentration gradient, actin organization patterns, vesicle trafficking, as well as the deposition and configuration of cell wall components. PMID:26710276

Glycogen phosphorylase in Acanthamoeba spp.: determining the role of the enzyme during the encystment process using RNA interference.

PubMed

Lorenzo-Morales, Jacob; Kliescikova, Jarmila; Martinez-Carretero, Enrique; De Pablos, Luis Miguel; Profotova, Bronislava; Nohynkova, Eva; Osuna, Antonio; Valladares, Basilio

2008-03-01

Acanthamoeba infections are difficult to treat due to often late diagnosis and the lack of effective and specific therapeutic agents. The most important reason for unsuccessful therapy seems to be the existence of a double-wall cyst stage that is highly resistant to the available treatments, causing reinfections. The major components of the Acanthamoeba cyst wall are acid-resistant proteins and cellulose. The latter has been reported to be the major component of the inner cyst wall. It has been demonstrated previously that glycogen is the main source of free glucose for the synthesis of cellulose in Acanthamoeba, partly as glycogen levels fall during the encystment process. In other lower eukaryotes (e.g., Dictyostelium discoideum), glycogen phosphorylase has been reported to be the main tool used for glycogen breakdown in order to maintain the free glucose levels during the encystment process. Therefore, it was hypothesized that the regulation of the key processes involved in the Acanthamoeba encystment may be similar to the previously reported regulation mechanisms in other lower eukaryotes. The catalytic domain of the glycogen phosphorylase was silenced using RNA interference methods, and the effect of this phenomenon was assessed by light and electron microscopy analyses, calcofluor staining, expression zymogram assays, and Northern and Western blot analyses of both small interfering RNA-treated and control cells. The present report establishes the role of glycogen phosphorylase during the encystment process of Acanthamoeba. Moreover, the obtained results demonstrate that the enzyme is required for cyst wall assembly, mainly for the formation of the cell wall inner layer.

Glycogen Phosphorylase in Acanthamoeba spp.: Determining the Role of the Enzyme during the Encystment Process Using RNA Interference▿

PubMed Central

Lorenzo-Morales, Jacob; Kliescikova, Jarmila; Martinez-Carretero, Enrique; De Pablos, Luis Miguel; Profotova, Bronislava; Nohynkova, Eva; Osuna, Antonio; Valladares, Basilio

2008-01-01

Acanthamoeba infections are difficult to treat due to often late diagnosis and the lack of effective and specific therapeutic agents. The most important reason for unsuccessful therapy seems to be the existence of a double-wall cyst stage that is highly resistant to the available treatments, causing reinfections. The major components of the Acanthamoeba cyst wall are acid-resistant proteins and cellulose. The latter has been reported to be the major component of the inner cyst wall. It has been demonstrated previously that glycogen is the main source of free glucose for the synthesis of cellulose in Acanthamoeba, partly as glycogen levels fall during the encystment process. In other lower eukaryotes (e.g., Dictyostelium discoideum), glycogen phosphorylase has been reported to be the main tool used for glycogen breakdown in order to maintain the free glucose levels during the encystment process. Therefore, it was hypothesized that the regulation of the key processes involved in the Acanthamoeba encystment may be similar to the previously reported regulation mechanisms in other lower eukaryotes. The catalytic domain of the glycogen phosphorylase was silenced using RNA interference methods, and the effect of this phenomenon was assessed by light and electron microscopy analyses, calcofluor staining, expression zymogram assays, and Northern and Western blot analyses of both small interfering RNA-treated and control cells. The present report establishes the role of glycogen phosphorylase during the encystment process of Acanthamoeba. Moreover, the obtained results demonstrate that the enzyme is required for cyst wall assembly, mainly for the formation of the cell wall inner layer. PMID:18223117

Role of polysaccharides in food, digestion, and health

PubMed Central

Lovegrove, A.; Edwards, C. H.; De Noni, I.; Patel, H.; El, S. N.; Grassby, T.; Zielke, C.; Ulmius, M.; Nilsson, L.; Butterworth, P. J.; Ellis, P. R; Shewry, P. R.

2017-01-01

ABSTRACT Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets. PMID:25921546

Role of polysaccharides in food, digestion, and health.

PubMed

Lovegrove, A; Edwards, C H; De Noni, I; Patel, H; El, S N; Grassby, T; Zielke, C; Ulmius, M; Nilsson, L; Butterworth, P J; Ellis, P R; Shewry, P R

2017-01-22

Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets.

The cell shape proteins MreB and MreC control cell morphogenesis by positioning cell wall synthetic complexes.

PubMed

Divakaruni, Arun V; Baida, Cyril; White, Courtney L; Gober, James W

2007-10-01

MreB, the bacterial actin homologue, is thought to function in spatially co-ordinating cell morphogenesis in conjunction with MreC, a protein that wraps around the outside of the cell within the periplasmic space. In Caulobacter crescentus, MreC physically associates with penicillin-binding proteins (PBPs) which catalyse the insertion of intracellularly synthesized precursors into the peptidoglycan cell wall. Here we show that MreC is required for the spatial organization of components of the peptidoglycan-synthesizing holoenzyme in the periplasm and MreB directs the localization of a peptidoglycan precursor synthesis protein in the cytosol. Additionally, fluorescent vancomycin (Van-FL) labelling revealed that the bacterial cytoskeletal proteins MreB and FtsZ, as well as MreC and RodA, were required for peptidoglycan synthetic activity. MreB and FtsZ were found to be required for morphogenesis of the polar stalk. FtsZ was required for a cell cycle-regulated burst of peptidoglycan synthesis early in the cell cycle resulting in the synthesis of cross-band structures, whereas MreB was required for lengthening of the stalk. Thus, the bacterial cytoskeleton and cell shape-determining proteins such as MreC, function in concert to orchestrate the localization of cell wall synthetic complexes resulting in spatially co-ordinated and efficient peptidoglycan synthetic activity.

Mechanistic understanding of cellular level of water in plant-based food material

NASA Astrophysics Data System (ADS)

Khan, Md. Imran H.; Kumar, C.; Karim, M. A.

2017-06-01

Understanding of water distribution in plant-based food material is crucial for developing an accurate heat and mass transfer drying model. Generally, in plant-based food tissue, water is distributed in three different spaces namely, intercellular water, intracellular water, and cell wall water. For hygroscopic material, these three types of water transport should be considered for actual understanding of heat and mass transfer during drying. However, there is limited study dedicated to the investigation of the moisture distribution in a different cellular environment in the plant-based food material. Therefore, the aim of the present study was to investigate the proportion of intercellular water, intracellular water, and cell wall water inside the plant-based food material. During this study, experiments were performed for two different plant-based food tissues namely, eggplant and potato tissue using 1H-NMR-T2 relaxometry. Various types of water component were calculated by using multicomponent fits of the T2 relaxation curves. The experimental result showed that in potato tissue 80-82% water exist in intracellular space; 10-13% water in intercellular space and only 4-6% water exist in the cell wall space. In eggplant tissue, 90-93% water in intracellular space, 4-6% water exists in intercellular space and the remaining percentage of water is recognized as cell wall water. The investigated results quantify different types of water in plant-based food tissue. The highest proportion of water exists in intracellular spaces. Therefore, it is necessary to include different transport mechanism for intracellular, intercellular and cell wall water during modelling of heat and mass transfer during drying.

Evidence that family 35 carbohydrate binding modules display conserved specificity but divergent function

PubMed Central

Montanier, Cedric; van Bueren, Alicia Lammerts; Dumon, Claire; Flint, James E.; Correia, Marcia A.; Prates, Jose A.; Firbank, Susan J.; Lewis, Richard J.; Grondin, Gilles G.; Ghinet, Mariana G.; Gloster, Tracey M.; Herve, Cecile; Knox, J. Paul; Talbot, Brian G.; Turkenburg, Johan P.; Kerovuo, Janne; Brzezinski, Ryszard; Fontes, Carlos M. G. A.; Davies, Gideon J.; Boraston, Alisdair B.; Gilbert, Harry J.

2009-01-01

Enzymes that hydrolyze complex carbohydrates play important roles in numerous biological processes that result in the maintenance of marine and terrestrial life. These enzymes often contain noncatalytic carbohydrate binding modules (CBMs) that have important substrate-targeting functions. In general, there is a tight correlation between the ligands recognized by bacterial CBMs and the substrate specificity of the appended catalytic modules. Through high-resolution structural studies, we demonstrate that the architecture of the ligand binding sites of 4 distinct family 35 CBMs (CBM35s), appended to 3 plant cell wall hydrolases and the exo-β-d-glucosaminidase CsxA, which contributes to the detoxification and metabolism of an antibacterial fungal polysaccharide, is highly conserved and imparts specificity for glucuronic acid and/or Δ4,5-anhydrogalaturonic acid (Δ4,5-GalA). Δ4,5-GalA is released from pectin by the action of pectate lyases and as such acts as a signature molecule for plant cell wall degradation. Thus, the CBM35s appended to the 3 plant cell wall hydrolases, rather than targeting the substrates of the cognate catalytic modules, direct their appended enzymes to regions of the plant that are being actively degraded. Significantly, the CBM35 component of CsxA anchors the enzyme to the bacterial cell wall via its capacity to bind uronic acid sugars. This latter observation reveals an unusual mechanism for bacterial cell wall enzyme attachment. This report shows that the biological role of CBM35s is not dictated solely by their carbohydrate specificities but also by the context of their target ligands. PMID:19218457

Comparative transcriptomics indicate changes in cell wall organization and stress response in seedlings during spaceflight.

PubMed

Johnson, Christina M; Subramanian, Aswati; Pattathil, Sivakumar; Correll, Melanie J; Kiss, John Z

2017-08-21

Plants will play an important role in the future of space exploration as part of bioregenerative life support. Thus, it is important to understand the effects of microgravity and spaceflight on gene expression in plant development. We analyzed the transcriptome of Arabidopsis thaliana using the Biological Research in Canisters (BRIC) hardware during Space Shuttle mission STS-131. The bioinformatics methods used included RMA (robust multi-array average), MAS5 (Microarray Suite 5.0), and PLIER (probe logarithmic intensity error estimation). Glycome profiling was used to analyze cell wall composition in the samples. In addition, our results were compared to those of two other groups using the same hardware on the same mission (BRIC-16). In our BRIC-16 experiments, we noted expression changes in genes involved in hypoxia and heat shock responses, DNA repair, and cell wall structure between spaceflight samples compared to the ground controls. In addition, glycome profiling supported our expression analyses in that there was a difference in cell wall components between ground control and spaceflight-grown plants. Comparing our studies to those of the other BRIC-16 experiments demonstrated that, even with the same hardware and similar biological materials, differences in results in gene expression were found among these spaceflight experiments. A common theme from our BRIC-16 space experiments and those of the other two groups was the downregulation of water stress response genes in spaceflight. In addition, all three studies found differential regulation of genes associated with cell wall remodeling and stress responses between spaceflight-grown and ground control plants. © 2017 Botanical Society of America.

Effect of arabinogalactan proteins from the root caps of pea and Brassica napus on Aphanomyces euteiches zoospore chemotaxis and germination.

PubMed

Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

2012-08-01

Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions.

Effect of Arabinogalactan Proteins from the Root Caps of Pea and Brassica napus on Aphanomyces euteiches Zoospore Chemotaxis and Germination12[C][W

PubMed Central

Cannesan, Marc Antoine; Durand, Caroline; Burel, Carole; Gangneux, Christophe; Lerouge, Patrice; Ishii, Tadashi; Laval, Karine; Follet-Gueye, Marie-Laure; Driouich, Azeddine; Vicré-Gibouin, Maïté

2012-01-01

Root tips of many plant species release a number of border, or border-like, cells that are thought to play a major role in the protection of root meristem. However, little is currently known on the structure and function of the cell wall components of such root cells. Here, we investigate the sugar composition of the cell wall of the root cap in two species: pea (Pisum sativum), which makes border cells, and Brassica napus, which makes border-like cells. We find that the cell walls are highly enriched in arabinose and galactose, two major residues of arabinogalactan proteins. We confirm the presence of arabinogalactan protein epitopes on root cap cell walls using immunofluorescence microscopy. We then focused on these proteoglycans by analyzing their carbohydrate moieties, linkages, and electrophoretic characteristics. The data reveal (1) significant structural differences between B. napus and pea root cap arabinogalactan proteins and (2) a cross-link between these proteoglycans and pectic polysaccharides. Finally, we assessed the impact of root cap arabinogalactan proteins on the behavior of zoospores of Aphanomyces euteiches, an oomycetous pathogen of pea roots. We find that although the arabinogalactan proteins of both species induce encystment and prevent germination, the effects of both species are similar. However, the arabinogalactan protein fraction from pea attracts zoospores far more effectively than that from B. napus. This suggests that root arabinogalactan proteins are involved in the control of early infection of roots and highlights a novel role for these proteoglycans in root-microbe interactions. PMID:22645070

Gravity resistance, another graviresponse in plants - role of microtubule-membrane-cell wall continuum

NASA Astrophysics Data System (ADS)

Hoson, T.; Saito, Y.; Usui, S.; Soga, K.; Wakabayashi, K.

Resistance to the gravitational force has been a serious problem for plants to survive on land, after they first went ashore more than 400 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. The hypothesis was further supported by space experiments during the Space Shuttle STS-95 mission. 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-hydroxy-3-methylglutaryl-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.

Comprehensive QTL mapping survey dissects the complex fruit texture physiology in apple (Malus x domestica Borkh.).

PubMed

Longhi, Sara; Moretto, Marco; Viola, Roberto; Velasco, Riccardo; Costa, Fabrizio

2012-02-01

Fruit ripening is a complex physiological process in plants whereby cell wall programmed changes occur mainly to promote seed dispersal. Cell wall modification also directly regulates the textural properties, a fundamental aspect of fruit quality. In this study, two full-sib populations of apple, with 'Fuji' as the common maternal parent, crossed with 'Delearly' and 'Pink Lady', were used to understand the control of fruit texture by QTL mapping and in silico gene mining. Texture was dissected with a novel high resolution phenomics strategy, simultaneously profiling both mechanical and acoustic fruit texture components. In 'Fuji × Delearly' nine linkage groups were associated with QTLs accounting from 15.6% to 49% of the total variance, and a highly significant QTL cluster for both textural components was mapped on chromosome 10 and co-located with Md-PG1, a polygalacturonase gene that, in apple, is known to be involved in cell wall metabolism processes. In addition, other candidate genes related to Md-NOR and Md-RIN transcription factors, Md-Pel (pectate lyase), and Md-ACS1 were mapped within statistical intervals. In 'Fuji × Pink Lady', a smaller set of linkage groups associated with the QTLs identified for fruit texture (15.9-34.6% variance) was observed. The analysis of the phenotypic variance over a two-dimensional PCA plot highlighted a transgressive segregation for this progeny, revealing two QTL sets distinctively related to both mechanical and acoustic texture components. The mining of the apple genome allowed the discovery of the gene inventory underlying each QTL, and functional profile assessment unravelled specific gene expression patterns of these candidate genes.

Nuclear reactor spacer grid and ductless core component

DOEpatents

Christiansen, David W.; Karnesky, Richard A.

1989-01-01

The invention relates to a nuclear reactor spacer grid member for use in a liquid cooled nuclear reactor and to a ductless core component employing a plurality of these spacer grid members. The spacer grid member is of the egg-shell type and is constructed so that the walls of the cell members of the grid member are formed of a single thickness of metal to avoid tolerance problems. Within each cell member is a hydraulic spring which laterally constrains the nuclear material bearing rod which passes through each cell member against a hardstop in response to coolant flow through the cell member. This hydraulic spring is also suitable for use in a water cooled nuclear reactor. A core component constructed of, among other components, a plurality of these spacer grid members, avoids the use of a full length duct by providing spacer sleeves about the sodium tubes passing through the spacer grid members at locations between the grid members, thereby maintaining a predetermined space between adjacent grid members.

Method and apparatus using an active ionic liquid for algae biofuel harvest and extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.

The invention relates to use of an active ionic liquid to dissolve algae cell walls. The ionic liquid is used to, in an energy efficient manner, dissolve and/or lyse an algae cell walls, which releases algae constituents used in the creation of energy, fuel, and/or cosmetic components. The ionic liquids include ionic salts having multiple charge centers, low, very low, and ultra low melting point ionic liquids, and combinations of ionic liquids. An algae treatment system is described, which processes wet algae in a lysing reactor, separates out algae constituent products, and optionally recovers the ionic liquid in an energymore » efficient manner.« less

In vitro decomposition of Sphagnum by some microfungi resembles white rot of wood.

PubMed

Rice, Adrianne V; Tsuneda, Akihiko; Currah, Randolph S

2006-06-01

The abilities of some ascomycetes (Myxotrichaceae) from a Sphagnum bog in Alberta to degrade cellulose, phenolics, and Sphagnum tissue were compared with those of two basidiomycetes. Most Myxotrichaceae degraded cellulose and tannic acid, and removed cell-wall components simultaneously from Sphagnum tissues, whereas the basidiomycetes degraded cellulose and insoluble phenolics, and preferentially removed the polyphenolic matrix from Sphagnum cell walls. Mass losses from Sphagnum varied from up to 50% for some ascomycetes to a maximum of 35% for the basidiomycetes. The decomposition of Sphagnum by the Myxotrichaceae was analogous to the white rot of wood and indicates that these fungi have the potential to cause significant mineralization of carbon in bogs.

Identification of a novel gene cluster in the upstream region of the S-layer gene sbpA involved in cell wall metabolism of Lysinibacillus sphaericus CCM 2177 and characterization of the recombinantly produced autolysin and pyruvyl transferase.

PubMed

Pleschberger, Magdalena; Hildner, Florian; Rünzler, Dominik; Gelbmann, Nicola; Mayer, Harald F; Sleytr, Uwe B; Egelseer, Eva M

2013-05-01

The S-layer protein SbpA of Lysinibacillus sphaericus CCM 2177 assembles into a square (p4) lattice structure and recognizes a pyruvylated secondary cell wall polymer (SCWP) as the proper anchoring structure to the rigid cell wall layer. Sequencing of 8,004 bp in the 5'-upstream region of the S-layer gene sbpA led to five ORFs-encoding proteins involved in cell wall metabolism. After cloning and heterologous expression of ORF1 and ORF5 in Escherichia coli, the recombinant autolysin rAbpA and the recombinant pyruvyl transferase rCsaB were isolated, purified, and correct folding was confirmed by circular dichroism. Although rAbpA encoded by ORF1 showed amidase activity, it could attack whole cells of Ly. sphaericus CCM 2177 only after complete extraction of the S-layer lattice. Despite the presence of three S-layer-homology motifs on the N-terminal part, rAbpA did not show detectable affinity to peptidoglycan-containing sacculi, nor to isolated SCWP. As the molecular mass of the autolysin lies above the molecular exclusion limit of the S-layer, AbpA is obviously trapped within the rigid cell wall layer by the isoporous protein lattice. Immunogold-labeling of ultrathin-sectioned whole cells of Ly. sphaericus CCM 2177 with a polyclonal rabbit antiserum raised against rCsaB encoded by ORF5, and cell fractionation experiments demonstrated that the pyruvyl transferase was located in the cytoplasm, but not associated with cell envelope components including the plasma membrane. In enzymatic assays, rCsaB clearly showed pyruvyl transferase activity. By using RT-PCR, specific transcripts for each ORF could be detected. Cotranscription could be confirmed for ORF2 and ORF3.

Inhibition of fucosylation of cell wall components by 2-fluoro 2-deoxy-L-fucose induces defects in root cell elongation.

PubMed

Dumont, Marie; Lehner, Arnaud; Bardor, Muriel; Burel, Carole; Vauzeilles, Boris; Lerouxel, Olivier; Anderson, Charles T; Mollet, Jean-Claude; Lerouge, Patrice

2015-12-01

Screening of commercially available fluoro monosaccharides as putative growth inhibitors in Arabidopsis thaliana revealed that 2-fluoro 2-l-fucose (2F-Fuc) reduces root growth at micromolar concentrations. The inability of 2F-Fuc to affect an Atfkgp mutant that is defective in the fucose salvage pathway indicates that 2F-Fuc must be converted to its cognate GDP nucleotide sugar in order to inhibit root growth. Chemical analysis of cell wall polysaccharides and glycoproteins demonstrated that fucosylation of xyloglucans and of N-linked glycans is fully inhibited by 10 μm 2F-Fuc in Arabidopsis seedling roots, but genetic evidence indicates that these alterations are not responsible for the inhibition of root development by 2F-Fuc. Inhibition of fucosylation of cell wall polysaccharides also affected pectic rhamnogalacturonan-II (RG-II). At low concentrations, 2F-Fuc induced a decrease in RG-II dimerization. Both RG-II dimerization and root growth were partially restored in 2F-Fuc-treated seedlings by addition of boric acid, suggesting that the growth phenotype caused by 2F-Fuc was due to a deficiency of RG-II dimerization. Closer investigation of the 2F-Fuc-induced growth phenotype demonstrated that cell division is not affected by 2F-Fuc treatments. In contrast, the inhibitor suppressed elongation of root cells and promoted the emergence of adventitious roots. This study further emphasizes the importance of RG-II in cell elongation and the utility of glycosyltransferase inhibitors as new tools for studying the functions of cell wall polysaccharides in plant development. Moreover, supplementation experiments with borate suggest that the function of boron in plants might not be restricted to RG-II cross-linking, but that it might also be a signal molecule in the cell wall integrity-sensing mechanism. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Direct Determination of Hydroxymethyl Conformations of Plant Cell Wall Cellulose Using 1H Polarization Transfer Solid-State NMR.

PubMed

Phyo, Pyae; Wang, Tuo; Yang, Yu; O'Neill, Hugh; Hong, Mei

2018-05-14

In contrast to the well-studied crystalline cellulose of microbial and animal origins, cellulose in plant cell walls is disordered due to its interactions with matrix polysaccharides. Plant cell wall (PCW) is an undisputed source of sustainable global energy; therefore, it is important to determine the molecular structure of PCW cellulose. The most reactive component of cellulose is the exocyclic hydroxymethyl group: when it adopts the tg conformation, it stabilizes intrachain and interchain hydrogen bonding, while gt and gg conformations destabilize the hydrogen-bonding network. So far, information about the hydroxymethyl conformation in cellulose has been exclusively obtained from 13 C chemical shifts of monosaccharides and oligosaccharides, which do not reflect the environment of cellulose in plant cell walls. Here, we use solid-state Nuclear Magnetic Resonance (ssNMR) spectroscopy to measure the hydroxymethyl torsion angle of cellulose in two model plants, by detecting distance-dependent polarization transfer between H4 and H6 protons in 2D 13 C- 13 C correlation spectra. We show that the interior crystalline portion of cellulose microfibrils in Brachypodium and Arabidopsis cell walls exhibits H4-H6 polarization transfer curves that are indicative of a tg conformation, whereas surface cellulose chains exhibit slower H4-H6 polarization transfer that is best fit to the gt conformation. Joint constraints by the H4-H6 polarization transfer curves and 13 C chemical shifts indicate that it is unlikely for interior cellulose to have a significant population of the gt and gg conformation mixed with the tg conformation, while surface cellulose may adopt a small percentage of the gg conformation. These results provide new constraints to the structure and matrix interactions of cellulose in plant cell walls, and represent the first direct determination of a torsion angle in an important noncrystalline carbohydrate polymer.

The Conserved Hypothetical Protein Rv0574c Is Required for Cell Wall Integrity, Stress Tolerance, and Virulence of Mycobacterium tuberculosis

PubMed Central

Garg, Rajni; Tripathi, Deeksha; Kant, Sashi; Chandra, Harish; Bhatnagar, Rakesh

2014-01-01

The virulence of Mycobacterium tuberculosis is intimately related to its distinctive cell wall. The biological significance of poly-α-l-glutamine (PLG), a component in the cell wall of virulent mycobacteria, has not been explored adequately. The focus of this study is to investigate the role of a locus, Rv0574c, coding for a polyglutamate synthase-like protein, in the synthesis of poly-α-l-glutamine in the context of mycobacterial virulence. Evaluation of Rv0574c gene expression in M. tuberculosis demonstrated its growth-phase-linked induction with concomitant accumulation of poly-α-l-glutamine in the cell wall. Rv0574c was activated under conditions prevalent in the tubercular granuloma, e.g., hypoxia, nitric oxide, and CO2. For functional characterization, we produced a deletion mutant of the Rv0574c gene by allelic exchange. The mutant produced smaller amounts of poly-α-l-glutamine in the cell wall than did the wild-type bacterium. Additionally, the increased sensitivity of the mutant to antitubercular drugs, SDS, lysozyme, and mechanical stress was accompanied by a drastic reduction in the ability to form biofilm. Growth of the ΔRv0574c strain was normal under in vitro conditions but was retarded in THP-1 macrophages and in the lungs and spleen of BALB/c mice. This was in agreement with histopathology of the lungs showing slow growth and less severe pathology than that of the wild-type strain. In summary, this study demonstrates that the protein encoded by the Rv0574c locus, by virtue of modulating PLG content in the cell wall, helps in maintaining cellular integrity in a hostile host environment. Also, its involvement in protecting the pathogen from host-generated lethal factors contributes to the infectious biology of M. tuberculosis. PMID:25312955

Identification of Cell Wall Synthesis Regulatory Genes Controlling Biomass Characteristics and Yield in Rice (Oryza Sativa)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Zhaohua PEng; Ronald, Palmela; Wang, Guo-Liang

This project aims to identify the regulatory genes of rice cell wall synthesis pathways using a cell wall removal and regeneration system. We completed the gene expression profiling studies following the time course from cell wall removal to cell wall regeneration in rice suspension cells. We also completed, total proteome, nuclear subproteome and histone modification studies following the course from cell wall removal and cell wall regeneration process. A large number of differentially expressed regulatory genes and proteins were identified. Meanwhile, we generated RNAi and over-expression transgenic rice for 45 genes with at least 10 independent transgenic lines for eachmore » gene. In addition, we ordered T-DNA and transposon insertion mutants for 60 genes from Korea, Japan, and France and characterized the mutants. Overall, we have mutants and transgenic lines for over 90 genes, exceeded our proposed goal of generating mutants for 50 genes. Interesting Discoveries a) Cell wall re-synthesis in protoplasts may involve a novel cell wall synthesis mechanism. The synthesis of the primary cell wall is initiated in late cytokinesis with further modification during cell expansion. Phragmoplast plays an essential role in cell wall synthesis. It services as a scaffold for building the cell plate and formation of a new cell wall. Only one phragmoplast and one new cell wall is produced for each dividing cell. When the cell wall was removed enzymatically, we found that cell wall re-synthesis started from multiple locations simultaneously, suggesting that a novel mechanism is involved in cell wall re-synthesis. This observation raised many interesting questions, such as how the starting sites of cell wall synthesis are determined, whether phragmoplast and cell plate like structures are involved in cell wall re-synthesis, and more importantly whether the same set of enzymes and apparatus are used in cell wall re-synthesis as during cytokinesis. Given that many known cell wall synthesis pathway genes are induced by removal of cell wall, some cell wall synthesis apparatus must be shared in both cases. The cell wall re-synthesis mechanism may have broad application because our preliminary assay indicates that the cell wall characteristics are highly different from those produced during cytokinesis. A thorough understanding on the regulation of cell wall re-synthesis may lead to improvement of cell wall characteristics. b) Removal of cell wall results in chromatin decondensation Another interesting observation was that removal of cell wall was associated with substantial chromatin change. Our DNA DAPI stain, chromatin MNase digestion, histone modification proteomics, protein differential expression analysis, and DNA oligo array studies all supported that substantial chromatin change was associated with removal of cell wall treatment. It is still under investigation if the chromatin change is associated with activation of cell wall synthesis genes, in which chromatin remodeling is required. Another possibility is that the cell wall is required for stabilizing the chromatin structure in plant cells. Given that spindle fiber is directly connected with both chromatin structure and cell wall synthesis, it is possible that there is an intrinsic connection between cell wall and chromatin.« less

Proteomic changes in chicken plasma induced by Salmonella typhimurium lipopolysaccharides

USDA-ARS?s Scientific Manuscript database

Lipopolysaccharides (LPS) are cell wall components of gram-negative bacteria that cause inflammation and sickness through genetic and proteomic activation. The objective of our study was to identify the proteomic changes in plasma associated with inflammation induced by LPS treatment. Five-week-old ...

Evaluation Of Airborne Endotoxin Concentrations Associated With Management Of Crop Grown On Applied Biosolids

EPA Science Inventory

Public health concerns have been expressed regarding inhalation exposure associated with the application of biosolids on cropland, which is due to the potential aerosolization of microorganisms, cell wall products, volatile chemicals, and nuisance odors. Endotoxin is a component...

Integrated -Omics: A Powerful Approach to Understanding the Heterogeneous Lignification of Fibre Crops

PubMed Central

Gea, Guerriero; Kjell, Sergeant; Jean-François, Hausman

2013-01-01

Lignin and cellulose represent the two main components of plant secondary walls and the most abundant polymers on Earth. Quantitatively one of the principal products of the phenylpropanoid pathway, lignin confers high mechanical strength and hydrophobicity to plant walls, thus enabling erect growth and high-pressure water transport in the vessels. Lignin is characterized by a high natural heterogeneity in its composition and abundance in plant secondary cell walls, even in the different tissues of the same plant. A typical example is the stem of fibre crops, which shows a lignified core enveloped by a cellulosic, lignin-poor cortex. Despite the great value of fibre crops for humanity, however, still little is known on the mechanisms controlling their cell wall biogenesis, and particularly, what regulates their spatially-defined lignification pattern. Given the chemical complexity and the heterogeneous composition of fibre crops’ secondary walls, only the use of multidisciplinary approaches can convey an integrated picture and provide exhaustive information covering different levels of biological complexity. The present review highlights the importance of combining high throughput -omics approaches to get a complete understanding of the factors regulating the lignification heterogeneity typical of fibre crops. PMID:23708098

A cryogenic high pressure cell for inelastic neutron scattering measurements of quantum fluids and solids.

PubMed

Carmichael, J R; Diallo, S O

2013-01-01

We present our new development of a high pressure cell for inelastic neutron scattering measurements of helium at ultra-low temperatures. The cell has a large sample volume of ~140 cm(3) and a working pressure of ~7 MPa, with a relatively thin wall-thickness (1.1 mm)--thanks to the high yield strength aluminum used in the design. Two variants of this cell have been developed. The first cell is permanently joined components using electron-beam welding and explosion welding, methods that have little or no impact on the global heat treatment of the cell. The second cell discussed has modular and interchangeable components, which includes a capacitance pressure gauge, that can be sealed using the traditional indium wire technique. The performance of the cells have been tested in recent measurements on superfluid liquid helium near the solidification line.

A cryogenic high pressure cell for inelastic neutron scattering measurements of quantum fluids and solids

NASA Astrophysics Data System (ADS)

Carmichael, J. R.; Diallo, S. O.

2013-01-01

We present our new development of a high pressure cell for inelastic neutron scattering measurements of helium at ultra-low temperatures. The cell has a large sample volume of ˜140 cm3 and a working pressure of ˜7 MPa, with a relatively thin wall-thickness (1.1 mm)—thanks to the high yield strength aluminum used in the design. Two variants of this cell have been developed. The first cell is permanently joined components using electron-beam welding and explosion welding, methods that have little or no impact on the global heat treatment of the cell. The second cell discussed has modular and interchangeable components, which includes a capacitance pressure gauge, that can be sealed using the traditional indium wire technique. The performance of the cells have been tested in recent measurements on superfluid liquid helium near the solidification line.

Expression of the high-affinity choline transporter CHT1 in rat and human arteries.

PubMed

Lips, Katrin S; Pfeil, Uwe; Reiners, Katja; Rimasch, Christoph; Kuchelmeister, Klaus; Braun-Dullaeus, Ruediger C; Haberberger, Rainer V; Schmidt, Rupert; Kummer, Wolfgang

2003-12-01

The arterial vascular wall contains a non-neuronal intrinsic cholinergic system. The rate-limiting step in acetylcholine (ACh) synthesis is choline uptake. A high-affinity choline transporter, CHT1, has recently been cloned from neural tissue and has been identified in epithelial cholinergic cells. Here we investigated its presence in rat and human arteries and in primary cell cultures of rat vascular cells (endothelial cells, smooth muscle cells, fibroblasts). CHT1-mRNA was detected in the arterial wall and in all isolated cell types by RT-PCR using five different CHT1-specific primer pairs. Antisera raised against amino acids 29-40 of the rat sequence labeled a single band (50 kD) in Western blots of rat aorta, and an additional higher molecular weight band appeared in the hippocampus. Immunohistochemistry demonstrated CHT1 immunoreactivity in endothelial and smooth muscle cells in situ and in all cultured cell types. A high-affinity [3H]-choline uptake mechanism sharing characteristics with neuronal high-affinity choline uptake, i.e., sensitivity to hemicholinium-3 and dependence on sodium, was demonstrated in rat thoracic aortic segments by microimager autoradiography. Expression of the high-affinity choline transporter CHT1 is a novel component of the intrinsic non-neuronal cholinergic system of the arterial vascular wall, predominantly in the intimal and medial layers.

Architecture of dermatophyte cell Walls: Electron microscopic and biochemical analysis

NASA Technical Reports Server (NTRS)

Nozawa, Y.; Kitajima, Y.

1984-01-01

A review with 83 references on the cell wall structure of dermatophytes is presented. Topics discussed include separation and preparation of cell walls; microstructure of cell walls by electron microscopy; chemical composition of cell walls; structural model of cell walls; and morphological structure of cell walls.

Arabidopsis Regenerating Protoplast: A Powerful Model System for Combining the Proteomics of Cell Wall Proteins and the Visualization of Cell Wall Dynamics

PubMed Central

Yokoyama, Ryusuke; Kuki, Hiroaki; Kuroha, Takeshi; Nishitani, Kazuhiko

2016-01-01

The development of a range of sub-proteomic approaches to the plant cell wall has identified many of the cell wall proteins. However, it remains difficult to elucidate the precise biological role of each protein and the cell wall dynamics driven by their actions. The plant protoplast provides an excellent means not only for characterizing cell wall proteins, but also for visualizing the dynamics of cell wall regeneration, during which cell wall proteins are secreted. It therefore offers a unique opportunity to investigate the de novo construction process of the cell wall. This review deals with sub-proteomic approaches to the plant cell wall through the use of protoplasts, a methodology that will provide the basis for further exploration of cell wall proteins and cell wall dynamics. PMID:28248244

A Cotton Annexin Affects Fiber Elongation and Secondary Cell Wall Biosynthesis Associated with Ca2+ Influx, ROS Homeostasis, and Actin Filament Reorganization1

PubMed Central

Zhang, Feng; Jin, Xuanxiang; Wang, Like; Li, Shufen; Wu, Shuang; Cheng, Chaoze; Zhang, Tianzhen

2016-01-01

Annexins play pivotal roles in a variety of cellular processes as well as in fiber development; however, the functional mechanisms of their activities are unclear. Here, an annexin gene that is preferentially expressed in fibers, GhFAnnxA, was found to be significantly associated with various cotton (Gossypium hirsutum) fiber traits. Transgenic analysis demonstrated that GhFAnnxA affected cotton fiber elongation and was involved in secondary cell wall (SCW) biosynthesis. Functional studies demonstrated that GhFAnnxA may act as a Ca2+ conductance regulator and that reactive oxygen species (ROS) produced by Rbohs in a Ca2+-dependent manner may determine fiber elongation caused by elevated intracellular turgor and cell wall loosening. However, excessive hydrogen peroxide (H2O2) inhibited cotton fiber elongation in vitro. We speculate that a positive feedback loop involving ROS and Ca2+ is regulated by GhCDPK1 and regulates fiber cell elongation. Furthermore, the convergence of actin filaments is altered by their interaction with GhFAnnxA, and this also may contribute to fiber elongation. Moreover, GhFAnnxA may affect SCW biosynthesis through changes in cell wall components caused by an increase in H2O2 levels. These results not only provide new insights into the signaling pathways of GhFAnnxA in fiber development but also clarify the role of ROS in fiber development. PMID:27255486

Infrared nanospectroscopy reveals the chemical nature of pit membranes in water-conducting cells of the plant xylem.

PubMed

Pereira, Luciano; Flores-Borges, Denisele; Bittencourt, Paulo; Mayer, Juliana; Kiyota, Eduardo; Araújo, Pedro; Jansen, Steven; Freitas, Raul; Oliveira, Rafael; Mazzafera, Paulo

2018-06-05

In the xylem of angiosperm plants, microscopic pits through the secondary cell walls connect the water-conducting vessels. Cellulosic meshes originated from primary walls and middle lamella between adjacent vessels, called pit membrane, separates one conduit from another. The intricate structure of the nano-sized pores in pit membranes enables the passage of water under negative pressure without hydraulic failure due to obstruction by gas bubbles (i.e., embolism) under normal conditions or mild drought stress. Since the chemical composition of pit membranes affects embolism formation and bubble behavior, we directly measured pit membrane composition in Populus nigra wood. Here, we characterized the chemical composition of cell wall structures by synchrotron infrared nanospectroscopy and atomic force microscopy-infrared nanospectroscopy with high spatial resolution. Characteristic peaks of cellulose, phenolic compounds, and proteins were found in the intervessel pit membrane of P. nigra wood. In addition, vessel to parenchyma pit membranes and developing cell walls of the vascular cambium showed clear signals of cellulose, proteins, and pectin. We did not find a distinct peak of lignin and other compounds in these structures. Our investigation of the complex chemical composition of intervessel pit membranes furthers our understanding of the flow of water and bubbles between neighboring conduits. The advances presented here pave the way for further label-free studies related to the nano-chemistry of plant cell components. {copyright, serif} 2018 American Society of Plant Biologists. All rights reserved.

Modifications to the composition of the hyphal outer layer of Aspergillus fumigatus modulates HUVEC proteins related to inflammatory and stress responses.

PubMed

Neves, Gabriela Westerlund Peixoto; Curty, Nathália de Andrade; Kubitschek-Barreira, Paula Helena; Fontaine, Thierry; Souza, Gustavo Henrique Martins Ferreira; Cunha, Marcel Lyra; Goldman, Gustavo H; Beauvais, Anne; Latgé, Jean-Paul; Lopes-Bezerra, Leila M

2017-01-16

Aspergillus fumigatus, the main etiologic agent causing invasive aspergillosis, can induce an inflammatory response and a prothrombotic phenotype upon contact with human umbilical vein endothelial cells (HUVECs). However, the fungal molecules involved in this endothelial response remain unknown. A. fumigatus hyphae produce an extracellular matrix composed of galactomannan, galactosaminogalactan and α-(1,3)-glucan. In this study, we investigated the consequences of UGM1 gene deletion in A. fumigatus, which produces a mutant with increased galactosaminogalactan production. The ∆ugm1 mutant exhibited an HUVEC-hyperadhesive phenotype and induced increased endothelial TNF-α secretion and tissue factor mRNA overexpression in this "semi-professional" immune host cell. Using a shotgun proteomics approach, we show that the A. fumigatus ∆ugm1 strain can modulate the levels of proteins in important endothelial pathways related to the inflammatory response mediated by TNF-α and to stress response pathways. Furthermore, a purified galactosaminogalactan fraction was also able to induce TNF-α secretion and the coincident HUVEC pathways regulated by the ∆ugm1 mutant, which overexpresses this component, as demonstrated by fluorescence microscopy. This work contributes new data regarding endothelial mechanisms in response to A. fumigatus infection. Invasive aspergillosis is the main opportunistic fungal infection described in neutropenic hematologic patients. One important clinical aspect of this invasive fungal infection is vascular thrombosis, which could be related, at least in part, to the activation of endothelial cells, as shown in previous reports from our group. It is known that direct contact between the A. fumigatus hyphal cell wall and the HUVEC cell surface is necessary to induce an endothelial prothrombotic phenotype and secretion of pro-inflammatory cytokines, though the cell surface components of this angioinvasive fungus that trigger this endothelial response are unknown. The present work employs a discovery-driven proteomics approach to reveal the role of one important cell wall polysaccharide of A. fumigatus, galactosaminogalactan, in the HUVEC interaction and the consequent mechanisms of endothelial activation. This is the first report of the overall panel of proteins related to the HUVEC response to a specific and purified cell wall component of the angioinvasive fungus A. fumigatus. Copyright © 2016 Elsevier B.V. All rights reserved.

Lignin Down-regulation of Zea mays via dsRNAi and Klason Lignin Analysis

PubMed Central

Park, Sang-Hyuck; Ong, Rebecca Garlock; Mei, Chuansheng; Sticklen, Mariam

2014-01-01

To facilitate the use of lignocellulosic biomass as an alternative bioenergy resource, during biological conversion processes, a pretreatment step is needed to open up the structure of the plant cell wall, increasing the accessibility of the cell wall carbohydrates. Lignin, a polyphenolic material present in many cell wall types, is known to be a significant hindrance to enzyme access. Reduction in lignin content to a level that does not interfere with the structural integrity and defense system of the plant might be a valuable step to reduce the costs of bioethanol production. In this study, we have genetically down-regulated one of the lignin biosynthesis-related genes, cinnamoyl-CoA reductase (ZmCCR1) via a double stranded RNA interference technique. The ZmCCR1_RNAi construct was integrated into the maize genome using the particle bombardment method. Transgenic maize plants grew normally as compared to the wild-type control plants without interfering with biomass growth or defense mechanisms, with the exception of displaying of brown-coloration in transgenic plants leaf mid-ribs, husks, and stems. The microscopic analyses, in conjunction with the histological assay, revealed that the leaf sclerenchyma fibers were thinned but the structure and size of other major vascular system components was not altered. The lignin content in the transgenic maize was reduced by 7-8.7%, the crystalline cellulose content was increased in response to lignin reduction, and hemicelluloses remained unchanged. The analyses may indicate that carbon flow might have been shifted from lignin biosynthesis to cellulose biosynthesis. This article delineates the procedures used to down-regulate the lignin content in maize via RNAi technology, and the cell wall compositional analyses used to verify the effect of the modifications on the cell wall structure. PMID:25080235

Lignin down-regulation of Zea mays via dsRNAi and klason lignin analysis.

PubMed

Park, Sang-Hyuck; Ong, Rebecca Garlock; Mei, Chuansheng; Sticklen, Mariam

2014-07-23

To facilitate the use of lignocellulosic biomass as an alternative bioenergy resource, during biological conversion processes, a pretreatment step is needed to open up the structure of the plant cell wall, increasing the accessibility of the cell wall carbohydrates. Lignin, a polyphenolic material present in many cell wall types, is known to be a significant hindrance to enzyme access. Reduction in lignin content to a level that does not interfere with the structural integrity and defense system of the plant might be a valuable step to reduce the costs of bioethanol production. In this study, we have genetically down-regulated one of the lignin biosynthesis-related genes, cinnamoyl-CoA reductase (ZmCCR1) via a double stranded RNA interference technique. The ZmCCR1_RNAi construct was integrated into the maize genome using the particle bombardment method. Transgenic maize plants grew normally as compared to the wild-type control plants without interfering with biomass growth or defense mechanisms, with the exception of displaying of brown-coloration in transgenic plants leaf mid-ribs, husks, and stems. The microscopic analyses, in conjunction with the histological assay, revealed that the leaf sclerenchyma fibers were thinned but the structure and size of other major vascular system components was not altered. The lignin content in the transgenic maize was reduced by 7-8.7%, the crystalline cellulose content was increased in response to lignin reduction, and hemicelluloses remained unchanged. The analyses may indicate that carbon flow might have been shifted from lignin biosynthesis to cellulose biosynthesis. This article delineates the procedures used to down-regulate the lignin content in maize via RNAi technology, and the cell wall compositional analyses used to verify the effect of the modifications on the cell wall structure.

Disruption of cellulose synthesis by 2,6-dichlorobenzonitrile affects the structure of the cytoskeleton and cell wall construction in Arabidopsis.

PubMed

Peng, L; Zhang, L; Cheng, X; Fan, L-S; Hao, H-Q

2013-03-01

Cellulose is the major component of plant cell walls and is an important source of industrial raw material. Although cellulose biosynthesis is one of the most important biochemical processes in plant biology, the regulatory mechanisms of cellulose synthesis are still unclear. Here, we report that 2,6-dichlorobenzonitrile (DCB), an inhibitor of cellulose synthesis, inhibits Arabidopsis root development in a dose- and time-dependent manner. When treated with DCB, the plant cell wall showed altered cellulose distribution and intensity, as shown by calcofluor white and S4B staining. Moreover, pectin deposition was reduced in the presence of DCB when immunostained with the monoclonal antibody JIM5, which was raised against pectin epitopes. This result was confirmed using Fourier transform infrared (FTIR) analysis. Confocal microscopy revealed that the organisation of the microtubule cytoskeleton was significantly disrupted in the presence of low concentrations of DCB, whereas the actin cytoskeleton only showed changes with the application of high DCB concentrations. In addition, the subcellular dynamics of Golgi bodies labelled with N-ST-YFP and TGN labelled with VHA-a1-GFP were both partially blocked by DCB. Transmission electron microscopy indicated that the cell wall structure was affected by DCB, as were the Golgi bodies. Scanning electron microscopy showed changes in the organisation of cellulose microfibrils. These results suggest that the inhibition of cellulose synthesis by DCB not only induced changes in the chemical composition of the root cell wall and cytoskeleton structure, but also changed the distribution of cellulose microfibrils, implying that cellulose plays an important role in root development in Arabidopsis. © 2012 German Botanical Society and The Royal Botanical Society of the Netherlands.

Isolation and Proteomic Characterization of the Arabidopsis Golgi Defines Functional and Novel Components Involved in Plant Cell Wall Biosynthesis1[W][OA

PubMed Central

Parsons, Harriet T.; Christiansen, Katy; Knierim, Bernhard; Carroll, Andrew; Ito, Jun; Batth, Tanveer S.; Smith-Moritz, Andreia M.; Morrison, Stephanie; McInerney, Peter; Hadi, Masood Z.; Auer, Manfred; Mukhopadhyay, Aindrila; Petzold, Christopher J.; Scheller, Henrik V.; Loqué, Dominique; Heazlewood, Joshua L.

2012-01-01

The plant Golgi plays a pivotal role in the biosynthesis of cell wall matrix polysaccharides, protein glycosylation, and vesicle trafficking. Golgi-localized proteins have become prospective targets for reengineering cell wall biosynthetic pathways for the efficient production of biofuels from plant cell walls. However, proteomic characterization of the Golgi has so far been limited, owing to the technical challenges inherent in Golgi purification. In this study, a combination of density centrifugation and surface charge separation techniques have allowed the reproducible isolation of Golgi membranes from Arabidopsis (Arabidopsis thaliana) at sufficiently high purity levels for in-depth proteomic analysis. Quantitative proteomic analysis, immunoblotting, enzyme activity assays, and electron microscopy all confirm high purity levels. A composition analysis indicated that approximately 19% of proteins were likely derived from contaminating compartments and ribosomes. The localization of 13 newly assigned proteins to the Golgi using transient fluorescent markers further validated the proteome. A collection of 371 proteins consistently identified in all replicates has been proposed to represent the Golgi proteome, marking an appreciable advancement in numbers of Golgi-localized proteins. A significant proportion of proteins likely involved in matrix polysaccharide biosynthesis were identified. The potential within this proteome for advances in understanding Golgi processes has been demonstrated by the identification and functional characterization of the first plant Golgi-resident nucleoside diphosphatase, using a yeast complementation assay. Overall, these data show key proteins involved in primary cell wall synthesis and include a mixture of well-characterized and unknown proteins whose biological roles and importance as targets for future research can now be realized. PMID:22430844

Deglycosylation systematically improves N-glycoprotein identification in liquid chromatography-tandem mass spectrometry proteomics for analysis of cell wall stress responses in Saccharomyces cerevisiae lacking Alg3p.

PubMed

Bailey, Ulla-Maja; Schulz, Benjamin L

2013-04-01

Post-translational modification of proteins with glycosylation is of key importance in many biological systems in eukaryotes, influencing fundamental biological processes and regulating protein function. Changes in glycosylation are therefore of interest in understanding these processes and are also useful as clinical biomarkers of disease. The presence of glycosylation can also inhibit protease digestion and lower the quality and confidence of protein identification by mass spectrometry. While deglycosylation can improve the efficiency of subsequent protease digest and increase protein coverage, this step is often excluded from proteomic workflows. Here, we performed a systematic analysis that showed that deglycosylation with peptide-N-glycosidase F (PNGase F) prior to protease digestion with AspN or trypsin improved the quality of identification of the yeast cell wall proteome. The improvement in the confidence of identification of glycoproteins following PNGase F deglycosylation correlated with a higher density of glycosylation sites. Optimal identification across the proteome was achieved with PNGase F deglycosylation and complementary proteolysis with either AspN or trypsin. We used this combination of deglycosylation and complementary protease digest to identify changes in the yeast cell wall proteome caused by lack of the Alg3p protein, a key component of the biosynthetic pathway of protein N-glycosylation. The cell wall of yeast lacking Alg3p showed specifically increased levels of Cis3p, a protein important for cell wall integrity. Our results showed that deglycosylation prior to protease digestion improved the quality of proteomic analyses even if protein glycosylation is not of direct relevance to the study at hand. Copyright © 2013 Elsevier B.V. All rights reserved.

Phylogeny in Defining Model Plants for Lignocellulosic Ethanol Production: A Comparative Study of Brachypodium distachyon, Wheat, Maize, and Miscanthus x giganteus Leaf and Stem Biomass

PubMed Central

Meineke, Till; Manisseri, Chithra; Voigt, Christian A.

2014-01-01

The production of ethanol from pretreated plant biomass during fermentation is a strategy to mitigate climate change by substituting fossil fuels. However, biomass conversion is mainly limited by the recalcitrant nature of the plant cell wall. To overcome recalcitrance, the optimization of the plant cell wall for subsequent processing is a promising approach. Based on their phylogenetic proximity to existing and emerging energy crops, model plants have been proposed to study bioenergy-related cell wall biochemistry. One example is Brachypodium distachyon, which has been considered as a general model plant for cell wall analysis in grasses. To test whether relative phylogenetic proximity would be sufficient to qualify as a model plant not only for cell wall composition but also for the complete process leading to bioethanol production, we compared the processing of leaf and stem biomass from the C3 grasses B. distachyon and Triticum aestivum (wheat) with the C4 grasses Zea mays (maize) and Miscanthus x giganteus, a perennial energy crop. Lambda scanning with a confocal laser-scanning microscope allowed a rapid qualitative analysis of biomass saccharification. A maximum of 108–117 mg ethanol·g−1 dry biomass was yielded from thermo-chemically and enzymatically pretreated stem biomass of the tested plant species. Principal component analysis revealed that a relatively strong correlation between similarities in lignocellulosic ethanol production and phylogenetic relation was only given for stem and leaf biomass of the two tested C4 grasses. Our results suggest that suitability of B. distachyon as a model plant for biomass conversion of energy crops has to be specifically tested based on applied processing parameters and biomass tissue type. PMID:25133818

Evaluation of Antifungal Activity and Mechanism of Action of Citral against Candida albicans.

PubMed

Leite, Maria Clerya Alvino; Bezerra, André Parente de Brito; de Sousa, Janiere Pereira; Guerra, Felipe Queiroga Sarmento; Lima, Edeltrudes de Oliveira

2014-01-01

Candida albicans is a yeast that commensally inhabits the human body and can cause opportunistic or pathogenic infections. Objective. To investigate the antifungal activity of citral against C. albicans. Methodology. The minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) were determined by the broth microdilution techniques. We also investigated possible citral action on cell walls (0.8 M sorbitol), cell membranes (citral to ergosterol binding), the time-kill curve, and biological activity on the yeast's morphology. Results. The MIC and MFC of citral were, respectively, 64 µg/mL and 256 µg/mL. Involvement with the cell wall and ergosterol binding were excluded as possible mechanisms of action. In the morphological interference assay, it was observed that the product inhibited pseudohyphae and chlamydoconidia formation. The MIC and the MFC of citral required only 4 hours of exposure to effectively kill 99.9% of the inoculum. Conclusion. Citral showed in vitro antifungal potential against strains of C. albicans. Citral's mechanism of action does not involve the cell wall or ergosterol, and further study is needed to completely describe its effects before being used in the future as a component of new antifungals.

Protonema of the moss Funaria hygrometrica can function as a lead (Pb) adsorbent

PubMed Central

Itouga, Misao; Hayatsu, Manabu; Sato, Mayuko; Tsuboi, Yuuri; Kato, Yukari; Toyooka, Kiminori; Suzuki, Suechika; Nakatsuka, Seiji; Kawakami, Satoshi; Kikuchi, Jun

2017-01-01

Water contamination by heavy metals from industrial activities is a serious environmental concern. To mitigate heavy metal toxicity and to recover heavy metals for recycling, biomaterials used in phytoremediation and bio-sorbent filtration have recently drawn renewed attention. The filamentous protonemal cells of the moss Funaria hygrometrica can hyperaccumulate lead (Pb) up to 74% of their dry weight when exposed to solutions containing divalent Pb. Energy-dispersive X-ray spectroscopy revealed that Pb is localized to the cell walls, endoplasmic reticulum-like membrane structures, and chloroplast thylakoids, suggesting that multiple Pb retention mechanisms are operating in living F. hygrometrica. The main Pb-accumulating compartment was the cell wall, and prepared cell-wall fractions could also adsorb Pb. Nuclear magnetic resonance analysis showed that polysaccharides composed of polygalacturonic acid and cellulose probably serve as the most effective Pb-binding components. The adsorption abilities were retained throughout a wide range of pH values, and bound Pb was not desorbed under conditions of high ionic strength. In addition, the moss is highly tolerant to Pb. These results suggest that the moss F. hygrometrica could be a useful tool for the mitigation of Pb-toxicity in wastewater. PMID:29261745

Turnover of microbial groups and cell components in soil: 13C analysis of cellular biomarkers

NASA Astrophysics Data System (ADS)

Gunina, Anna; Dippold, Michaela; Glaser, Bruno; Kuzyakov, Yakov

2017-01-01

Microorganisms regulate the carbon (C) cycle in soil, controlling the utilization and recycling of organic substances. To reveal the contribution of particular microbial groups to C utilization and turnover within the microbial cells, the fate of 13C-labelled glucose was studied under field conditions. Glucose-derived 13C was traced in cytosol, amino sugars and phospholipid fatty acid (PLFA) pools at intervals of 3, 10 and 50 days after glucose addition into the soil. 13C enrichment in PLFAs ( ˜ 1.5 % of PLFA C at day 3) was an order of magnitude greater than in cytosol, showing the importance of cell membranes for initial C utilization. The 13C enrichment in amino sugars of living microorganisms at day 3 accounted for 0.57 % of total C pool; as a result, we infer that the replacement of C in cell wall components is 3 times slower than that of cell membranes. The C turnover time in the cytosol (150 days) was 3 times longer than in PLFAs (47 days). Consequently, even though the cytosol pool has the fastest processing rates compared to other cellular compartments, intensive recycling of components here leads to a long C turnover time. Both PLFA and amino-sugar profiles indicated that bacteria dominated in glucose utilization. 13C enrichment decreased with time for bacterial cell membrane components, but it remained constant or even increased for filamentous microorganisms. 13C enrichment of muramic acid was the 3.5 times greater than for galactosamine, showing a more rapid turnover of bacterial cell wall components compared to fungal. Thus, bacteria utilize a greater proportion of low-molecular-weight organic substances, whereas filamentous microorganisms are responsible for further C transformations. Thus, tracing 13C in cellular compounds with contrasting turnover rates elucidated the role of microbial groups and their cellular compartments in C utilization and recycling in soil. The results also reflect that microbial C turnover is not restricted to the death or growth of new cells. Indeed, even within living cells, highly polymeric cell compounds are constantly replaced and renewed. This is especially important for assessing C fluxes in soil and the contribution of C from microbial residues to soil organic matter.

Characterization of the Sclerotinia sclerotiorum cell wall proteome.

PubMed

Liu, Longzhou; Free, Stephen J

2016-08-01

We used a proteomic analysis to identify cell wall proteins released from Sclerotinia sclerotiorum hyphal and sclerotial cell walls via a trifluoromethanesulfonic acid (TFMS) digestion. Cell walls from hyphae grown in Vogel's glucose medium (a synthetic medium lacking plant materials), from hyphae grown in potato dextrose broth and from sclerotia produced on potato dextrose agar were used in the analysis. Under the conditions used, TFMS digests the glycosidic linkages in the cell walls to release intact cell wall proteins. The analysis identified 24 glycosylphosphatidylinositol (GPI)-anchored cell wall proteins and 30 non-GPI-anchored cell wall proteins. We found that the cell walls contained an array of cell wall biosynthetic enzymes similar to those found in the cell walls of other fungi. When comparing the proteins in hyphal cell walls grown in potato dextrose broth with those in hyphal cell walls grown in the absence of plant material, it was found that a core group of cell wall biosynthetic proteins and some proteins associated with pathogenicity (secreted cellulases, pectin lyases, glucosidases and proteases) were expressed in both types of hyphae. The hyphae grown in potato dextrose broth contained a number of additional proteins (laccases, oxalate decarboxylase, peroxidase, polysaccharide deacetylase and several proteins unique to Sclerotinia and Botrytis) that might facilitate growth on a plant host. A comparison of the proteins in the sclerotial cell wall with the proteins in the hyphal cell wall demonstrated that sclerotia formation is not marked by a major shift in the composition of cell wall protein. We found that the S. sclerotiorum cell walls contained 11 cell wall proteins that were encoded only in Sclerotinia and Botrytis genomes. © 2015 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.

Mimicking the Humidity Response of the Plant Cell Wall by Using Two-Dimensional Systems: The Critical Role of Amorphous and Crystalline Polysaccharides.

PubMed

Niinivaara, Elina; Faustini, Marco; Tammelin, Tekla; Kontturi, Eero

2016-03-01

Of the composite materials occurring in nature, the plant cell wall is among the most intricate, consisting of a complex arrangement of semicrystalline cellulose microfibrils in a dissipative matrix of lignin and hemicelluloses. Here, a biomimetic, two-dimensional cellulose system of the cell wall structure is introduced where cellulose nanocrystals compose the crystalline portion and regenerated amorphous cellulose composes the dissipative matrix. Spectroscopic ellipsometry and QCM-D are used to study the water vapor uptake of several two-layer systems. Quantitative analysis shows that the vapor-induced swelling of these ultrathin films can be controlled by varying ratios of the chemically identical ordered and unordered cellulose components. Intriguingly, increasing the share of crystalline cellulose appeared to increase the vapor uptake but only in cases for which the interfacial area between the crystalline and amorphous area was relatively large and the thickness of an amorphous overlayer was relatively small. The results show that a biomimetic approach may occasionally provide answers as to why certain native structures exist.

Combining FT-IR spectroscopy and multivariate analysis for qualitative and quantitative analysis of the cell wall composition changes during apples development.

PubMed

Szymanska-Chargot, M; Chylinska, M; Kruk, B; Zdunek, A

2015-01-22

The aim of this work was to quantitatively and qualitatively determine the composition of the cell wall material from apples during development by means of Fourier transform infrared (FT-IR) spectroscopy. The FT-IR region of 1500-800 cm(-1), containing characteristic bands for galacturonic acid, hemicellulose and cellulose, was examined using principal component analysis (PCA), k-means clustering and partial least squares (PLS). The samples were differentiated by development stage and cultivar using PCA and k-means clustering. PLS calibration models for galacturonic acid, hemicellulose and cellulose content from FT-IR spectra were developed and validated with the reference data. PLS models were tested using the root-mean-square errors of cross-validation for contents of galacturonic acid, hemicellulose and cellulose which was 8.30 mg/g, 4.08% and 1.74%, respectively. It was proven that FT-IR spectroscopy combined with chemometric methods has potential for fast and reliable determination of the main constituents of fruit cell walls. Copyright © 2014 Elsevier Ltd. All rights reserved.

Syncytia in plants: cell fusion in endosperm-placental syncytium formation in Utricularia (Lentibulariaceae).

PubMed

Płachno, Bartosz J; Swiątek, Piotr

2011-04-01

The syncytium formed by Utricularia is extremely unusual and perhaps unique among angiosperm syncytia. All typical plant syncytia (articulated laticifers, amoeboid tapetum, the nucellar plasmodium of river weeds) are formed only by fusion of sporophytic cells which possess the same genetic material, unlike Utricularia in which the syncytium possesses nuclei from two different sources: cells of maternal sporophytic nutritive tissue and endosperm haustorium (both maternal and paternal genetic material). How is this kind of syncytium formed and organized and is it similar to other plant syncytial structures? We used light and electron microscopy to reconstruct the step-by-step development of the Utricularia syncytia. The syncytia of Utricularia developed through heterotypic cell fusion involving the digestion of the cell wall, and finally, heterokaryotic multinucleate structures were formed, which possessed different-sized nuclei that were not regularly arranged in the cytoplasm. We showed that these syncytia were characterized by hypertrophy of nuclei, abundant endoplasmic reticulum and organelles, and the occurrence of wall ingrowths. All these characters testify to high activity and may confirm the nutritive and transport functions of the syncytium for the developing embryo. In Utricularia, the formation of the syncytium provides an economical way to redistribute cell components and release nutrients from the digested cell walls, which can now be used for the embryo, and finally to create a large surface for the exchange of nutrients between the placenta and endosperm.

The impact of multi-walled carbon nanotubes (MWCNTs) on macrophages: contribution of MWCNT characteristics.

PubMed

Li, Yinghe; Cao, Jimin

2018-05-22

Multi-walled carbon nanotubes (MWCNTs) have wide application prospects but also exhibit notable biotoxicity that is tightly associated with macrophages. Macrophages simultaneously act as initiators and defenders in MWCNT-induced organ lesions, and targeting macrophages with MWCNTs may be a potential immunotherapy and oncotherapy approach. This review focuses on the impacts of MWCNTs on macrophages and further discusses the influence of MWCNT characteristics on their bioactivity. Based on existing studies, MWCNTs stimulate macrophage migration, induce secretion of various cytokines and activate inflammatory pathways in macrophages, especially NLRP3-mediated IL-1β production. This inflammatory state, together with the oxidative stress and cell membrane lesions induced by MWCNTs, contributes to decreased phagocytic ability and cell viability, which finally results in cell apoptosis and necrosis. A series of intracellular and systemic components, such as toll-like receptor, high-mobility group box 1, Rho-associated kinases, scavenger receptor and complement components, may be involved in the above-mentioned cell-MWCNT interactions. The characteristics of MWCNTs can influence their bioactivity in macrophages both mechanically and chemically. The size (length and/or diameter), functionalization, purification and even the experimental method can affect the influence of MWCNTs on macrophages, and a better understanding of these MWCNT characteristics may benefit utilization of this nanomaterial in associated nanomedical applications.

Chemical Composition, Antibacterial Properties and Mechanism of Action of Essential Oil from Clove Buds against Staphylococcus aureus.

PubMed

Xu, Jian-Guo; Liu, Ting; Hu, Qing-Ping; Cao, Xin-Ming

2016-09-08

The essential oil of clove has a wide range of pharmacological and biological activities and is widely used in the medicine, fragrance and flavoring industries. In this work, 22 components of the essential oil obtained from clove buds were identified. Eugenol was the major component (76.23%). The essential oil exhibited strong antibacterial activity against Staphylococcus aureus ATCC 25923 with a minimum inhibitory concentration (MIC) of 0.625 mg/mL, and the antibacterial effects depended on its concentration and action time. Kill-time assays also confirmed the essential oil had a significant effect on the growth rate of surviving S. aureus. We hypothesized that the essential oil may interact with the cell wall and membrane first. On the one hand it destroys cell wall and membranes, next causing the losses of vital intracellular materials, which finally result in the bacterial death. Besides, essential oil penetrates to the cytoplasmic membrane or enters inside the cell after destruction of cell structure, and then inhibits the normal synthesis of DNA and proteins that are required for bacterial growth. These results suggested that the effects of the clove essential oil on the growth inhibition of S. aureus may be at the molecular level rather than only physical damage.

Cell wall mannoprotein of Candida albicans induces cell cycle alternation and inhibits apoptosis of HaCaT cells via NF-κB signal pathway.

PubMed

Han, Yang; Jiang, Hang-Hang; Zhang, Yu-Jing; Hao, Xing-Jia; Sun, Yu-Zhe; Qi, Rui-Qun; Chen, Hong-Duo; Gao, Xing-Hua

2017-10-01

Candida albicans (C. albicans) is a commensal organism in human and a well-known dimorphic opportunistic pathogenic fungus. Though plenty of researches on the pathogenesis of C. albicans have been performed, the mechanism is not fully understood. The cell wall components of C. albicans have been documented to play important roles in its pathogenic processes. To further study the infectious mechanism of C. albicans, we investigated the potential functional role of its cell wall mannoprotein in cell cycle and apoptosis of HaCaT cells. We found that mannoprotein could promote the transition of cell cycle from G1/G0 to S phase, in which Cyclin D1, CDK4 and p-Rb, the major regulators of the cell cycle progression, showed significant upregulation, and CDKN1A (cyclin dependent kinase inhibitor 1A (p21)) showed significant downregulation. Mannoprotein also could inhibit apoptosis of HaCaT cells, which was well associated with increased expression of BCL2 (Bcl-2). Moreover, mannoprotein could increase the phosphorylation levels of RELA (p65) and NFKBIA (IκBα), as the key factors of NF-κB signal pathway in HaCaT cells, suggesting the activation of NF-κB signal pathway. Additionally, a NF-κB specific inhibitor, PDTC, could rescue the effect of mannoprotein on cell cycle and apoptosis of HaCaT cells, which suggested that mannoprotein could activate NF-κB signal pathway to mediate cell cycle alternation and inhibit apoptosis. Copyright © 2017. Published by Elsevier Ltd.

The Role of Auxin in Cell Wall Expansion

PubMed Central

2018-01-01

Plant cells are surrounded by cell walls, which are dynamic structures displaying a strictly regulated balance between rigidity and flexibility. Walls are fairly rigid to provide support and protection, but also extensible, to allow cell growth, which is triggered by a high intracellular turgor pressure. Wall properties regulate the differential growth of the cell, resulting in a diversity of cell sizes and shapes. The plant hormone auxin is well known to stimulate cell elongation via increasing wall extensibility. Auxin participates in the regulation of cell wall properties by inducing wall loosening. Here, we review what is known on cell wall property regulation by auxin. We focus particularly on the auxin role during cell expansion linked directly to cell wall modifications. We also analyze downstream targets of transcriptional auxin signaling, which are related to the cell wall and could be linked to acid growth and the action of wall-loosening proteins. All together, this update elucidates the connection between hormonal signaling and cell wall synthesis and deposition. PMID:29565829

The Role of Auxin in Cell Wall Expansion.

PubMed

Majda, Mateusz; Robert, Stéphanie

2018-03-22

Plant cells are surrounded by cell walls, which are dynamic structures displaying a strictly regulated balance between rigidity and flexibility. Walls are fairly rigid to provide support and protection, but also extensible, to allow cell growth, which is triggered by a high intracellular turgor pressure. Wall properties regulate the differential growth of the cell, resulting in a diversity of cell sizes and shapes. The plant hormone auxin is well known to stimulate cell elongation via increasing wall extensibility. Auxin participates in the regulation of cell wall properties by inducing wall loosening. Here, we review what is known on cell wall property regulation by auxin. We focus particularly on the auxin role during cell expansion linked directly to cell wall modifications. We also analyze downstream targets of transcriptional auxin signaling, which are related to the cell wall and could be linked to acid growth and the action of wall-loosening proteins. All together, this update elucidates the connection between hormonal signaling and cell wall synthesis and deposition.

Honeycomb-Fin Heat Sink

NASA Technical Reports Server (NTRS)

Rippel, Wally E.

1989-01-01

Improved finned heat sink for electronic components more lightweight, inexpensive, and efficient. Designed for use with forced air, easily scaled up to dissipate power up to few hundred watts. Fins are internal walls of aluminum honeycomb structure. Cell structure gives strength to thin aluminum foil. Length of channels chosen for thermodynamic efficency; columns of cells combined in any reasonable number because flowing air distributed to all. Heat sink cools nearly as effectively at ends as near its center, no matter how many columns of cells combined.

Experimental investigation of internal short circuits in lithium-ion batteries

NASA Astrophysics Data System (ADS)

Poramapojana, Poowanart

With outstanding performance of Lithium-ion batteries, they have been widely used in many applications. For hybrid electric vehicles and electric vehicles, customer concerns of battery safety have been raised as a number of car accidents were reported. To evaluate safety performance of these batteries, a nail penetration test is used to simulate and induce internal short circuits instantaneously. Efforts to explain failure mechanisms of the penetration using electrochemical-thermal coupled models have been proposed. However, there is no experimental validation because researchers lack of a diagnostic tool to acquire important cell characteristics at a shorting location, such as shorting current and temperature. In this present work, diagnostic nails have been developed to acquire nail center temperatures and shorting current flow through the nails during nail penetration tests. Two types of cylindrical wall structures are used to construct the nails: a double-layered stainless steel wall and a composite cylindrical wall. An inner hollow cylinder functions as a sensor holder where two wires and one thermocouple are installed. To study experimental reproducibility and repeatability of experimental results, two nail penetration tests are conducted using two diagnostic nails with the double-layered wall. Experimental data shows that the shorting resistance at the initial stage is a critical parameter to obtain repeatable results. The average shorting current for both tests is approximately 40 C-rate. The fluctuation of the shorting current is due to random sparks and fire caused loose contacts between the nail and the cell components. Moreover, comparative experimental results between the two wall structures reveal that the wall structure does not affect the cell characteristics and Ohmic heat generation of the nail. The wall structure effects to current measurements inside the nail. With the composite wall, the actual current redistribution into the inner wall is found to be a sinusoidal waveform.

Superresolution Imaging of Dynamic MreB Filaments in B. subtilis—A Multiple-Motor-Driven Transport?

PubMed Central

Olshausen, Philipp v.; Defeu Soufo, Hervé Joël; Wicker, Kai; Heintzmann, Rainer; Graumann, Peter L.; Rohrbach, Alexander

2013-01-01

The cytoskeletal protein MreB is an essential component of the bacterial cell-shape generation system. Using a superresolution variant of total internal reflection microscopy with structured illumination, as well as three-dimensional stacks of deconvolved epifluorescence microscopy, we found that inside living Bacillus subtilis cells, MreB forms filamentous structures of variable lengths, typically not longer than 1 μm. These filaments move along their orientation and mainly perpendicular to the long bacterial axis, revealing a maximal velocity at an intermediate length and a decreasing velocity with increasing filament length. Filaments move along straight trajectories but can reverse or alter their direction of propagation. Based on our measurements, we provide a mechanistic model that is consistent with all observations. In this model, MreB filaments mechanically couple several motors that putatively synthesize the cell wall, whereas the filaments’ traces mirror the trajectories of the motors. On the basis of our mechanistic model, we developed a mathematical model that can explain the nonlinear velocity length dependence. We deduce that the coupling of cell wall synthesis motors determines the MreB filament transport velocity, and the filament mechanically controls a concerted synthesis of parallel peptidoglycan strands to improve cell wall stability. PMID:24010660

Superresolution imaging of dynamic MreB filaments in B. subtilis--a multiple-motor-driven transport?

PubMed

Olshausen, Philipp V; Defeu Soufo, Hervé Joël; Wicker, Kai; Heintzmann, Rainer; Graumann, Peter L; Rohrbach, Alexander

2013-09-03

The cytoskeletal protein MreB is an essential component of the bacterial cell-shape generation system. Using a superresolution variant of total internal reflection microscopy with structured illumination, as well as three-dimensional stacks of deconvolved epifluorescence microscopy, we found that inside living Bacillus subtilis cells, MreB forms filamentous structures of variable lengths, typically not longer than 1 μm. These filaments move along their orientation and mainly perpendicular to the long bacterial axis, revealing a maximal velocity at an intermediate length and a decreasing velocity with increasing filament length. Filaments move along straight trajectories but can reverse or alter their direction of propagation. Based on our measurements, we provide a mechanistic model that is consistent with all observations. In this model, MreB filaments mechanically couple several motors that putatively synthesize the cell wall, whereas the filaments' traces mirror the trajectories of the motors. On the basis of our mechanistic model, we developed a mathematical model that can explain the nonlinear velocity length dependence. We deduce that the coupling of cell wall synthesis motors determines the MreB filament transport velocity, and the filament mechanically controls a concerted synthesis of parallel peptidoglycan strands to improve cell wall stability. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Antimicrobial Peptides Targeting Gram-Positive Bacteria

PubMed Central

Malanovic, Nermina; Lohner, Karl

2016-01-01

Antimicrobial peptides (AMPs) have remarkably different structures as well as biological activity profiles, whereupon most of these peptides are supposed to kill bacteria via membrane damage. In order to understand their molecular mechanism and target cell specificity for Gram-positive bacteria, it is essential to consider the architecture of their cell envelopes. Before AMPs can interact with the cytoplasmic membrane of Gram-positive bacteria, they have to traverse the cell wall composed of wall- and lipoteichoic acids and peptidoglycan. While interaction of AMPs with peptidoglycan might rather facilitate penetration, interaction with anionic teichoic acids may act as either a trap for AMPs or a ladder for a route to the cytoplasmic membrane. Interaction with the cytoplasmic membrane frequently leads to lipid segregation affecting membrane domain organization, which affects membrane permeability, inhibits cell division processes or leads to delocalization of essential peripheral membrane proteins. Further, precursors of cell wall components, especially the highly conserved lipid II, are directly targeted by AMPs. Thereby, the peptides do not inhibit peptidoglycan synthesis via binding to proteins like common antibiotics, but form a complex with the precursor molecule, which in addition can promote pore formation and membrane disruption. Thus, the multifaceted mode of actions will make AMPs superior to antibiotics that act only on one specific target. PMID:27657092

Rumen bacteria: interaction with particulate dietary components and response to dietary variation.

PubMed

Cheng, K J; Akin, D E; Costerton, J W

1977-02-01

The bovine rumen resembles many other ecosystems in that its component bacterial cells are universally surrounded and protected by extracellular structures. The most common form of these structures is a fibrous carbohydrate slime that extends away from the cell and may mediate the attachment of the bacterium to a surface. This attachment is relatively specific and it may occur at the surface of the rumen epithelium or on the cell walls of a specific tissue within the plant-derived food of the animal. The production of the extracellular slime is under nutritional control and slime may be overproduced when soluble carbohydrates are available in high concentration. This overproduction results in cell-cell adhesion among the rumen bacteria with the eventual formation of slime-enclosed microcolonies and, in extreme cases, the generation of sufficient viscosity to cause feedlot bloat.

Yeast pro- and paraprobiotics have the capability to bind pathogenic bacteria associated with animal disease

USDA-ARS?s Scientific Manuscript database

Live yeast probiotics and yeast cell wall components (paraprobiotics) may serve as an alternative to the use of antibiotics in prevention and treatment of infections caused by pathogenic bacteria. Probiotics and paraprobiotics can bind directly to pathogens, which limits binding of the pathogens to ...

Vitamins E and C - effects on matrix components in the vascular system

USDA-ARS?s Scientific Manuscript database

The connective tissue in the vascular system, consisting mainly of vascular smooth muscle cells (VSMC) and the interstitial extracellular matrix (ECM), plays important roles in the maintenance of an intact vascular wall as well as in the repair of atherosclerotic lesions during disease development. ...

Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism

USDA-ARS?s Scientific Manuscript database

The architecture of the human distal gut microbiota (microbiota) is sculpted by the complex carbohydrates delivered in the diet. Yeasts, which are among the earliest domesticated microorganisms and have been a component of the human diet for at least 7000 years, possess an elaborate cell wall alpha-...

Molecular analysis of the Candida albicans homolog of Saccharomyces cerevisiae MNN9, required for glycosylation of cell wall mannoproteins.

PubMed

Southard, S B; Specht, C A; Mishra, C; Chen-Weiner, J; Robbins, P W

1999-12-01

The fungal cell wall has generated interest as a potential target for developing antifungal drugs, and the genes encoding glucan and chitin in fungal pathogens have been studied to this end. Mannoproteins, the third major component of the cell wall, contain mannose in either O- or N-glycosidic linkages. Here we describe the molecular analysis of the Candida albicans homolog of Saccharomyces cerevisiae MNN9, a gene required for the synthesis of N-linked outer-chain mannan in yeast, and the phenotypes associated with its disruption. CaMNN9 has significant homology with S. cerevisiae MNN9, including a putative N-terminal transmembrane domain, and represents a member of a similar gene family in Candida. CaMNN9 resides on chromosome 3 and is expressed at similar levels in both yeast and hyphal cells. Disruption of both copies of CaMNN9 leads to phenotypic effects characteristic of cell wall defects including poor growth in liquid media and on solid media, formation of aggregates in liquid culture, osmotic sensitivity, aberrant hyphal formation, and increased sensitivity to lysis after treatment with beta-1,3-glucanase. Like all members of the S. cerevisiae MNN9 gene family the Camnn9Delta strain is resistant to sodium orthovanadate and sensitive to hygromycin B. Analysis of cell wall-associated carbohydrates showed the Camnn9Delta strain to contain half the amount of mannan present in cell walls derived from the wild-type parent strain. Reverse transcription-PCR and Northern analysis of the expression of MNN9 gene family members CaVAN1 and CaANP1 in the Camnn9Delta strain showed that transcription of those genes is not affected in the absence of CaMNN9 transcription. Our results suggest that, while the role MNN9 plays in glycosylation in both Candida and Saccharomyces is conserved, loss of MNN9 function in C. albicans leads to phenotypes that are inconsistent with the pathogenicity of the organism and thus identify CaMnn9p as a potential drug target.