scholarly journals Effect of maize internode lignification on in vitro cell-wall polysaccharide degradability

1995 ◽  
Vol 44 (Suppl. 1) ◽  
pp. 34-34
Author(s):  
HG Jung ◽  
TA Morrison ◽  
DR Buxton
Keyword(s):  
Cell Wall ◽  
Cell Wall Polysaccharide

scholarly journals Direct evidence for a new mode of plant defense against insects via a novel polygalacturonase-inhibiting protein expression strategy

2020 ◽  
Vol 295 (33) ◽  
pp. 11833-11844
Author(s):  
Wiebke Haeger ◽  
Jana Henning ◽  
David G. Heckel ◽  
Yannick Pauchet ◽  
Roy Kirsch
Keyword(s):  
Cell Wall ◽  
Plant Defense ◽  
Plant Cell Wall ◽  
Direct Evidence ◽  
Larval Growth ◽  
Gene Families ◽  
Preliminary Evidence ◽  
Cell Wall Polysaccharide ◽  
In Planta

Plant cell wall–associated polygalacturonase-inhibiting proteins (PGIPs) are widely distributed in the plant kingdom. They play a crucial role in plant defense against phytopathogens by inhibiting microbial polygalacturonases (PGs). PGs hydrolyze the cell wall polysaccharide pectin and are among the first enzymes to be secreted during plant infection. Recent studies demonstrated that herbivorous insects express their own PG multi-gene families, raising the question whether PGIPs also inhibit insect PGs and protect plants from herbivores. Preliminary evidence suggested that PGIPs may negatively influence larval growth of the leaf beetle Phaedon cochleariae (Coleoptera: Chrysomelidae) and identified BrPGIP3 from Chinese cabbage (Brassica rapa ssp. pekinensis) as a candidate. PGIPs are predominantly studied in planta because their heterologous expression in microbial systems is problematic and instability and aggregation of recombinant PGIPs has complicated in vitro inhibition assays. To minimize aggregate formation, we heterologously expressed BrPGIP3 fused to a glycosylphosphatidylinositol (GPI) membrane anchor, immobilizing it on the extracellular surface of insect cells. We demonstrated that BrPGIP3_GPI inhibited several P. cochleariae PGs in vitro, providing the first direct evidence of an interaction between a plant PGIP and an animal PG. Thus, plant PGIPs not only confer resistance against phytopathogens, but may also aid in defense against herbivorous beetles.

scholarly journals A mixed-linkage (1,3;1,4)-β-D-glucan specific hydrolase mediates dark-triggered degradation of this plant cell wall polysaccharide

2021 ◽  
Author(s):  
Florian J Kraemer ◽  
China Lunde ◽  
Moritz Koch ◽  
Benjamin M Kuhn ◽  
Clemens Ruehl ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Cell ◽  
Large Scale ◽  
Plant Cell Wall ◽  
Causative Mutation ◽  
Grass Species ◽  
Calorie Intake ◽  
Cell Wall Polysaccharide ◽  
Transcript Accumulation

Abstract The presence of mixed-linkage (1,3;1,4)-β-D-glucan (MLG) in plant cell walls is a key feature of grass species such as cereals, the main source of calorie intake for humans and cattle. Accumulation of this polysaccharide involves the coordinated regulation of biosynthetic and metabolic machineries. While several components of the MLG biosynthesis machinery have been identified in diverse plant species, degradation of MLG is poorly understood. In this study, we performed a large-scale forward genetic screen for maize (Zea mays) mutants with altered cell wall polysaccharide structural properties. As a result, we identified a maize mutant with increased MLG content in several tissues, including adult leaves and senesced organs, where only trace amounts of MLG are usually detected. The causative mutation was found in the GRMZM2G137535 gene, encoding a GH17 licheninase as demonstrated by an in vitro activity assay of the heterologously expressed protein. In addition, maize plants overexpressing GRMZM2G137535 exhibit a 90% reduction in MLG content, indicating that the protein is not only required, but its expression is sufficient to degrade MLG. Accordingly, the mutant was named MLG hydrolase 1 (mlgh1). mlgh1 plants show increased saccharification yields upon enzymatic digestion. Stacking mlgh1 with lignin-deficient mutations results in synergistic increases in saccharification. Time profiling experiments indicate that wall MLG content is modulated during day/night cycles, inversely associated with MLGH1 transcript accumulation. This cycling is absent in the mlgh1 mutant, suggesting that the mechanism involved requires MLG degradation, which may in turn regulate MLGH1 gene expression.

Partial disintegration of vegetable cell wall during cooking improves vitamin K1 (Phylloquinone) bioaccessibility in in vitro digestion

2021 ◽  
pp. 1-12
Author(s):  
Wichien Sriwichai ◽  
Myriam Collin ◽  
Sylvie Avallone
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Principal Component ◽  
In Vitro Digestion ◽  
Leafy Vegetables ◽  
Cell Wall Polysaccharide ◽  
Water Spinach ◽  
Brassica Alboglabra ◽  
Ipomoea Aquatic

Abstract. Vegetables rich in vitamin K consumption could prevent bleeding and maintain bone status. The aims of the present work were to investigate i) the effect of household cooking (i.e., boiling for 5 min at 100 °C in distilled water and stir-frying for 3 min at 180 °C in hot canola oil) on phylloquinone bioaccessibility of five rich phylloquinone leafy vegetables, namely Water spinach (Ipomoea aquatic Forssk), Amaranth (Amaranthus blitum subsp. oleraceus L.), Chinese broccoli (Brassica alboglabra), Pak choi (Brassica rapa L.) and Drumstick (Moringa oleifera Lam.), and ii) the structural changes of these leaves before and after in vitro gastro-intestinal digestion. All the experiments were realized in triplicate for each vegetable. The amounts of phylloquinone in leafy vegetables were noticeable in almost all species and ranged from 94 to 182 μg/100 g DM. Their cell wall polysaccharide contents greatly varied from 4.3 to 8.4 g for 100 g. The content in bioaccessible phylloquinone was low in raw leaves (<25 μg/100 g DM) as well as its bioaccessibility (<15%). Leaf pectin content impaired phylloquinone bioaccessibility using principal component analysis. Boiling and stir-frying significantly improved the bioaccessibility of phylloquinone in leaves by a factor of three to twelve and two to seven respectively (p<0.05). These variations were associated with changes in leaf structure. Palisade and spongy cells appeared ruptured and disorganized after stir-frying. Given the estimated bioaccessibility of phylloquinones, the consumption of 500 g of cooked wet leaves per day would cover phylloquinone needs of an individual adult average body weight.

Isolation of pectin-enriched products from red beet (Beta vulgaris L. var. conditiva) wastes: composition and functional properties

2011 ◽  
Vol 17 (6) ◽  
pp. 517-527 ◽  
Author(s):  
E.N. Fissore ◽  
N.M.A. Ponce ◽  
L. Matkovic ◽  
C.A. Stortz ◽  
A.M. Rojas ◽  
...  
Keyword(s):  
Cell Wall ◽  
Beta Vulgaris ◽  
Extraction Process ◽  
Physiological Effect ◽  
Cell Wall Polysaccharide ◽  
Citrate Buffer ◽  
Red Beet ◽  
Cross Links ◽  
By Products

The present work was dedicated to the development of an extraction process for red beet ( Beta vulgaris L. var. conditiva) by-products that preserves the high molecular weight of the macromolecules with the primary aim of waste upgrading. Our study concerns the extraction of pectin-enriched products with potential thickening properties for their usage in food formulation, as well as with some healthy physiological effect, by using citrate buffer (pH = 5.2) either alone or with enzymes (hemicellulase or cellulase) active on cell wall polysaccharide networks. Considering that red beet tissue contains ferulic acid, which cross-links pectin macromolecules through arabinose residues to anchor them into the cell wall, an alkaline pretreatment was also evaluated in order to perform polysaccharide hydrolysis in the cell wall network to accomplish higher renderings. Chemical composition and yield, as well as the in vitro glucose retention exerted by the isolated fiber products were finally analyzed.

scholarly journals Protection against Pneumococcal Colonization and Fatal Pneumonia by a Trivalent Conjugate of a Fusion Protein with the Cell Wall Polysaccharide

2009 ◽  
Vol 77 (5) ◽  
pp. 2076-2083 ◽  
Author(s):  
Ying-Jie Lu ◽  
Sophie Forte ◽  
Claudette M. Thompson ◽  
Porter W. Anderson ◽  
Richard Malley
Keyword(s):  
Cell Wall ◽  
Fusion Protein ◽  
Serum Antibody ◽  
Cell Wall Polysaccharide ◽  
Interleukin 17A ◽  
Antibody Titers ◽  
Pneumococcal Colonization ◽  
Common Antigens ◽  
Subcutaneous Immunization

ABSTRACT Cell wall polysaccharide (CWPS), pneumolysin, and surface adhesin A (PsaA) are antigens common to virtually all serotypes of Streptococcus pneumoniae (pneumococcus), and all have been studied separately for use in protection. Previously we showed that protection against nasopharyngeal (NP) colonization by intranasal vaccination of mice with killed pneumococci is mediated by TH17 cells and correlates with interleukin-17A (IL-17A) expression by T cells in vitro; we have also shown that CWPS and other species-common antigens protect against colonization by a similar mechanism. Here we made a fusion protein of PsaA with the pneumolysin nontoxic derivative PdT and then coupled CWPS to the fusion protein, aiming to enhance immune responses to all three antigens. When given intranasally with cholera toxin adjuvant, the fusion conjugate induced higher serum antibody titers and greater priming for IL-17A responses than an equimolar mixture of the three antigens. The conjugate administered intranasally protected mice against experimental NP colonization by a strain of serotype 6B, while mice immunized with the mixture or with bivalent conjugates were not protected. Subcutaneous immunization with the conjugate and alum adjuvant likewise induced higher antibody titers than the mixture, primed for IL-17A responses, and reduced colonization. The conjugate, but not the antigen mixture, fully protected mice from fatal pneumonia caused by a highly virulent serotype 3 strain. Thus, a covalent construct of three antigens common to all serotypes exhibits protection with both mucosal and systemic administration.

scholarly journals Distinct Pathways Carry Out α and β Galactosylation of Secondary Cell Wall Polysaccharide in Bacillus anthracis

2020 ◽  
Vol 202 (15) ◽  
Author(s):  
Alice Chateau ◽  
So Young Oh ◽  
Anastasia Tomatsidou ◽  
Inka Brockhausen ◽  
Olaf Schneewind ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Anthracis ◽  
Secondary Cell Wall ◽  
Turgor Pressure ◽  
Cell Wall Polysaccharide ◽  
Bacterial Cells ◽  
Content Type ◽  
Repeat Units ◽  
Undecaprenyl Phosphate

ABSTRACT Bacillus anthracis, the causative agent of anthrax disease, elaborates a secondary cell wall polysaccharide (SCWP) that is required for the retention of surface layer (S-layer) and S-layer homology (SLH) domain proteins. Genetic disruption of the SCWP biosynthetic pathway impairs growth and cell division. B. anthracis SCWP is comprised of trisaccharide repeats composed of one ManNAc and two GlcNAc residues with O-3–α-Gal and O-4–β-Gal substitutions. UDP-Gal, synthesized by GalE1, is the substrate of galactosyltransferases that modify the SCWP repeat. Here, we show that the gtsE gene, which encodes a predicted glycosyltransferase with a GT-A fold, is required for O-4–β-Gal modification of trisaccharide repeats. We identify a DXD motif critical for GtsE activity. Three distinct genes, gtsA, gtsB, and gtsC, are required for O-3–α-Gal modification of trisaccharide repeats. Based on the similarity with other three-component glycosyltransferase systems, we propose that GtsA transfers Gal from cytosolic UDP-Gal to undecaprenyl phosphate (C55-P), GtsB flips the C55-P-Gal intermediate to the trans side of the membrane, and GtsC transfers Gal onto trisaccharide repeats. The deletion of galE1 does not affect growth in vitro, suggesting that galactosyl modifications are dispensable for the function of SCWP. The deletion of gtsA, gtsB, or gtsC leads to a loss of viability, yet gtsA and gtsC can be deleted in strains lacking galE1 or gtsE. We propose that the loss of viability is caused by the accumulation of undecaprenol-bound precursors and present an updated model for SCWP assembly in B. anthracis to account for the galactosylation of repeat units. IMPORTANCE Peptidoglycan is a conserved extracellular macromolecule that protects bacterial cells from turgor pressure. Peptidoglycan of Gram-positive bacteria serves as a scaffold for the attachment of polymers that provide defined bacterial interactions with their environment. One such polymer, B. anthracis SCWP, is pyruvylated at its distal end to serve as a receptor for secreted proteins bearing the S-layer homology domain. Repeat units of SCWP carry three galactoses in B. anthracis. Glycosylation is a recurring theme in nature and often represents a means to mask or alter conserved molecular signatures from intruders such as bacteriophages. Several glycosyltransferase families have been described based on bioinformatics prediction, but few have been studied. Here, we describe the glycosyltransferases that mediate the galactosylation of B. anthracis SCWP.

scholarly journals Galactosylation of the Secondary Cell Wall Polysaccharide ofBacillus anthracisand Its Contribution to Anthrax Pathogenesis

2017 ◽  
Vol 200 (5) ◽  
Author(s):  
Alice Chateau ◽  
Justin Mark Lunderberg ◽  
So Young Oh ◽  
Teresa Abshire ◽  
Arthur Friedlander ◽  
...  
Keyword(s):  
Cell Wall ◽  
Glutamic Acid ◽  
Bacillus Anthracis ◽  
Secondary Cell Wall ◽  
Cell Wall Polysaccharide ◽  
Wild Type ◽  
Content Type ◽  
Bacterial Inoculum ◽  
Associated Proteins

ABSTRACTBacillus anthracis, the causative agent of anthrax disease, elaborates a secondary cell wall polysaccharide (SCWP) that is essential for bacterial growth and cell division.B. anthracisSCWP is comprised of trisaccharide repeats with the structure, [→4)-β-ManNAc-(1→4)-β-GlcNAc(O3-α-Gal)-(1→6)-α-GlcNAc(O3-α-Gal,O4-β-Gal)-(1→]6-12. The genes whose products promote the galactosylation ofB. anthracisSCWP are not yet known. We show here that the expression ofgalE1, encoding a UDP-glucose 4-epimerase necessary for the synthesis of UDP-galactose, is required forB. anthracisSCWP galactosylation. ThegalE1mutant assembles surface (S) layer and S layer-associated proteins that associate with ketal-pyruvylated SCWP via their S layer homology domains similarly to wild-typeB. anthracis, but the mutant displays a defect in γ-phage murein hydrolase binding to SCWP. Furthermore, deletion ofgalE1diminishes the capsulation ofB. anthraciswith poly-d-γ-glutamic acid (PDGA) and causes a reduction in bacterial virulence. These data suggest that SCWP galactosylation is required for the physiologic assembly of theB. anthraciscell wall envelope and for the pathogenesis of anthrax disease.IMPORTANCEUnlike virulentBacillus anthracisisolates,B. anthracisstrain CDC684 synthesizes secondary cell wall polysaccharide (SCWP) trisaccharide repeats without galactosyl modification, exhibits diminished growthin vitroin broth cultures, and is severely attenuated in an animal model of anthrax. To examine whether SCWP galactosylation is a requirement for anthrax disease, we generated variants ofB. anthracisstrains Sterne 34F2 and Ames lacking UDP-glucose 4-epimerase by mutating the genesgalE1andgalE2. We identifiedgalE1as necessary for SCWP galactosylation. Deletion ofgalE1decreased the poly-d-γ-glutamic acid (PDGA) capsulation of the vegetative form ofB. anthracisand increased the bacterial inoculum required to produce lethal disease in mice, indicating that SCWP galactosylation is indeed a determinant of anthrax disease.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

In vitro assembly of 2-D crystals from partially purified EA1 protein secreted by Bacillus anthracis strain Delta Sterne-1

1994 ◽  
Vol 52 ◽  
pp. 276-277
Author(s):  
Mary Beth Downs ◽  
Wilson Ribot ◽  
Joseph W. Farchaus
Keyword(s):  
Cell Wall ◽  
Molecular Sieves ◽  
Cell Envelope ◽  
Single Species ◽  
Supporting Cell ◽  
Surface Layers ◽  
Rabbit Igg ◽  
In Vitro Assembly ◽  
Covalently Linked

Many bacteria possess surface layers (S-layers) that consist of a two-dimensional protein lattice external to the cell envelope. These S-layer arrays are usually composed of a single species of protein or glycoprotein and are not covalently linked to the underlying cell wall. When removed from the cell, S-layer proteins often reassemble into a lattice identical to that found on the cell, even without supporting cell wall fragments. S-layers exist at the interface between the cell and its environment and probably serve as molecular sieves that exclude destructive macromolecules while allowing passage of small nutrients and secreted proteins. Some S-layers are refractory to ingestion by macrophages and, generally, bacteria are more virulent when S-layers are present.When grown in rich medium under aerobic conditions, B. anthracis strain Delta Sterne-1 secretes large amounts of a proteinaceous extractable antigen 1 (EA1) into the growth medium. Immunocytochemistry with rabbit polyclonal anti-EAl antibody made against the secreted protein and gold-conjugated goat anti-rabbit IgG showed that EAI was localized at the cell surface (fig 1), which suggests its role as an S-layer protein.

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