scholarly journals Xyloglucan homeostasis and microtubule dynamics synergistically maintain meristem geometry and robustness of phyllotaxis in Arabidopsis

2019 ◽  
Author(s):  
Feng Zhao ◽  
Wenqian Chen ◽  
Julien Sechet ◽  
Marjolaine Martin ◽  
Simone Bovio ◽  
...  
Keyword(s):  
Cell Wall ◽  
Biochemical Analysis ◽  
Methylation Status ◽  
Active Role ◽  
Cellulose Content ◽  
Wall Stiffness ◽  
Micro Indentation ◽  
Precise Role ◽  
Wall Components

ABSTRACTThe shoot apical meristem (SAM) gives rise to all aerial organs of the plant. The cell walls are supposed to play a central role in this process, translating molecular regulation into dynamic changes of growth rates and directions, although their precise role in morphogenesis during organ formation remains not well understood. Here we investigate the role of xyloglucans (XyGs), which form a major, yet functionally poorly characterized, wall component in the SAM. Using immunolabeling, biochemical analysis, genetic approaches, micro-indentation, laser ablations and live imaging, we show that XyGs are important for meristem shape and phyllotaxis, although no difference in cell wall stiffness could be observed when XyGs are perturbed. Mutations in enzymes required for XyG synthesis also affect other cell wall components such as cellulose content and the pectin methylation status. Interestingly, we show that the control of cortical microtubules dynamics by the severing enzyme KATANIN becomes vital when XyGs are perturbed or absent. This suggests an active role of the cytoskeleton in compensating for altered wall composition.

Corrigendum - The role of wheat non-starch polysaccharides in broiler nutrition

1993 ◽  
Vol 44 (3) ◽  
pp. 405 ◽  
Author(s):  
G Annison
Keyword(s):  
Cell Wall ◽  
Broiler Chickens ◽  
Gut Microflora ◽  
Cell Wall Polysaccharides ◽  
Growth Depression ◽  
Cell Wall Components ◽  
Metabolisable Energy ◽  
Wall Components

It has been well established over a number of years that the apparent metabolisable energy (AME) value of wheat is highly variable. In 1983 and 1987 in Australia two surveys indicated that approximately 25% of wheats have AME values lower than 13 MJ/kg.DM (range 10.4-15.9 MJ/kg.DM). Following recent studies it has been proposed that the soluble non-starch polysaccharide cell-wall components of wheat (mainly arabinoxylan with some G-glucan) have an anti-nitritive activity when wheats are present at high levels in broiler diets and are responsible for the low-AME wheat phenomenon. The main findings supporting this hypothesis are (1) wheat AME values are negatively correlated with soluble non-starch polysaccharide levels, (2) low level addition (30g/kg) of commercially available pur non-starch polysaccharides to broiler diets depresses the AME,of the diets, (3) degradation of the cell wall polysaccharides in situ by addition of glycanases to broiler diets raises AME values, and (4) addition of purified wheat arabinoxylan to broiler diets depresses the AME in a dose-dependant manner. The AME depression is a result of the inhibition of starch, lipid and proteindigestion in the fore-gut. This paper reviews the experiments and the data from the studies and discusses further aspects of the anti-nutritive activity of cereal polysaccharides in broiler diets. The possible role of the gut microflora in the growth depression observed when diets containing high levels of rye, barley and wheat are fed to broiler chickens is also examined.

scholarly journals The role of pro-domains in human growth factors and cytokines

2021 ◽  
Author(s):  
Matthew Ratcliff ◽  
Richard Xu Zhou ◽  
Lutz Jermutus ◽  
Marko Hyvönen
Keyword(s):  
Growth Factors ◽  
Therapeutic Potential ◽  
Human Growth ◽  
Active Role ◽  
Proteolytic Processing ◽  
Protein Families ◽  
Protein Localisation ◽  
Precise Role ◽  
Bioactive Ligand

Many growth factors and cytokines are produced as larger precursors, containing pro-domains, that require proteolytic processing to release the bioactive ligand. These pro-domains can be significantly larger than the mature domains and can play an active role in the regulation of the ligands. Mining the UniProt database, we identified almost one hundred human growth factors and cytokines with pro-domains. These are spread across several unrelated protein families and vary in both their size and composition. The precise role of each pro-domain varies significantly between the protein families. Typically they are critical for controlling bioactivity and protein localisation, and they facilitate diverse mechanisms of activation. Significant gaps in our understanding remain for pro-domain function — particularly their fate once the bioactive ligand has been released. Here we provide an overview of pro-domain roles in human growth factors and cytokines, their processing, regulation and activation, localisation as well as therapeutic potential.

scholarly journals Elucidating The Multifunctional Role of The Cell Wall Components in The Maize Exploitation

2020 ◽  
Author(s):  
Ana López-Malvar ◽  
Rosa Ana Malvar ◽  
Xose Carlos Souto ◽  
Leonardo Dario Gomez ◽  
Rachael Simister ◽  
...  
Keyword(s):  
Cell Wall ◽  
Ethanol Production ◽  
Cell Walls ◽  
Pest Resistance ◽  
Inbred Lines ◽  
Polymer Composition ◽  
Cellulose Content ◽  
Cell Wall Components ◽  
Forage Digestibility ◽  
Wall Components

Abstract Background: Besides the use of maize grain as food and feed, maize stover can be a profitable by-product for cellulosic ethanol production, whereas the whole plant can be used in silage production. However, yield is reduced by pest damages, where stem corn borers are one of the most important factors limiting yield. Overall, cell wall composition is key in determining the quality of maize biomass, as well as pest resistance. This study aims to address the interrelations between cell wall components in diverse maize genotypes, and pest resistance, ethanolic production and forage digestibility. Results: We can highlight the following results: (i) pests resistant inbred lines may show cell walls with low p-coumaric acid and hemicellulose content; (ii) inbred lines showing cell walls with high cellulose content and diferulate cross-linking may present higher performance in ethanol production; (iii) and inbred lines with enhanced digestibility may have cell walls poor in neutral detergent fibre and diferulates, combined with a lignin polymer composition richer in G subunits. Conclusions: Our results evidence that there is no maize cell wall ideotype among the tested for optimal performance in the three areas evaluated, and maize plants should be specifically bred for each particular application.

scholarly journals Mechanistic studies on the biosorption of Pb(II) by Pseudomonas aeruginosa

2018 ◽  
Vol 78 (2) ◽  
pp. 290-300
Author(s):  
S. Vimalnath ◽  
H. Ravishankar ◽  
C. Schwandt ◽  
R. V. Kumar ◽  
S. Subramanian
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Treatment Method ◽  
Enzymatic Treatment ◽  
Intact Cells ◽  
Cell Wall Components ◽  
Before And After ◽  
Pseudo Second Order ◽  
Wall Components

Abstract The biosorption of Pb(II) ions from aqueous solution has been studied using both the intact and thermolyzed cells of Pseudomonas aeruginosa. Further, the role of the major cell wall components, namely DNA, protein, polysaccharide, and lipid, in Pb(II) binding has been assessed using an enzymatic treatment method. The Pb(II) bioremediation capability of P. aeruginosa cells has been investigated by varying the parameters of pH, time of interaction, amount of biomass, and concentration of Pb(II). The complete bioremoval of Pb(II) using intact cells has been achieved for an initial Pb(II) concentration of 12.4 mg L−1 at pH 6.2 and temperature 29 ± 1 °C. The biosorption isotherm follows Langmuirian behavior with a Gibbs free energy of −30.7 kJ mol−1, indicative of chemisorption. The biosorption kinetics is consistent with a pseudo-second-order model. The possible Pb(II) binding mechanisms of P. aeruginosa cells are discussed based on characterization using zeta potential measurements, Fourier transform infra-red spectroscopy, and energy dispersive X-ray spectroscopy. The results confirm that among the major cell wall components studied, polysaccharide shows the highest contribution towards Pb(II) binding, followed by DNA, lipid, and protein. Similar studies using thermolyzed cells show higher Pb(II) uptake compared to the intact cells both before and after enzymatic treatment.

Cell Walls of the Phycobionts Trebouxia and Pseudotrebouxia: Constituents and Their Localization

1984 ◽  
Vol 16 (2) ◽  
pp. 129-144 ◽  
Author(s):  
J. König ◽  
E. Peveling
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Cell Wall Composition ◽  
Recognition Mechanism ◽  
Absorption Spectrophotometry ◽  
Species Specific ◽  
Layer Chromatography ◽  
Polysaccharide Layer ◽  
Wall Components

AbstractThe cell wall composition of several species of the lichen phycobionts Trebouxia and Pseudotrebouxia has been investigated using gas chromatography, thin layer chromatography and infrared absorption spectrophotometry. In addition cell wall components (cellulose, non-cellulosic polysaccharides, sporopollenin, protein) were localized with cytochemical methods at the EM- level. The cell walls of Trebouxia and Pseudotrebouxia consist of several layers. In Trebouxia the inner layer (Si) consists mainly of cellulose, then followed by a non-cellulosic polysaccharide layer (S2), a sporopollenin-layer (S3) and an outer layer consisting again of a non-cellulosic polysaccharide (S4). In addition Trebouxia is surrounded by a sheath (a polysaccharide with species-specific terminal residues). In Pseudotrebouxia the cell wall is similarly constructed compared to Trebouxia, however, the sheath is lacking and the S4 layer contains a polysaccharide with species-specific terminal sugar residues. The role of the different cell wall constituents for the recognition mechanism between the lichen symbionts is discussed.

scholarly journals Expansin-controlled cell wall stiffness regulates root growth in Arabidopsis

2020 ◽  
Author(s):  
Marketa Samalova ◽  
Kareem Elsayad ◽  
Alesia Melnikava ◽  
Alexis Peaucelle ◽  
Evelina Gahurova ◽  
...  
Keyword(s):  
Cell Wall ◽  
Root Growth ◽  
Cell Types ◽  
Root Apical Meristem ◽  
Specific Cell ◽  
Wall Stiffness ◽  
Specific Localization ◽  
Dependent Cell ◽  
Cell Type Specific

ABSTRACTExpansins facilitate cell expansion via mediating pH-dependent cell wall (CW) loosening. However, the role of expansins in the control of biomechanical CW properties in the tissue and organ context remains elusive. We determined hormonal responsiveness and specificity of expression and localization of expansins predicted to be direct targets of cytokinin signalling. We found EXPA1 homogenously distributed throughout the CW of columella/ lateral root cap, while EXPA10 and EXPA14 localized predominantly at the three-cell boundaries of epidermis/cortex in various root zones. Cell type-specific localization of EXPA15 overlaps with higher CW stiffness measured via Brillouin light scattering microscopy. As indicated by both Brillouin frequency shift and AFM-measured Young’s modulus, EXPA1 overexpression upregulated CW stiffness, associated with shortening of the root apical meristem and root growth arrest. We propose that root growth in Arabidopsis requires delicate orchestration of biomechanical CW properties via tight regulation of various expansins’ localization to specific cell types and extracellular domains.

scholarly journals The Role of Soluble Polysaccharides in Tannin-Cell Wall Interactions in Model Solutions and in Wines

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 36 ◽  
Author(s):  
Andrea Osete-Alcaraz ◽  
Ana Belén Bautista-Ortín ◽  
Encarna Gómez-Plaza
Keyword(s):  
Cell Wall ◽  
Alcoholic Fermentation ◽  
Model Solution ◽  
Small Scale ◽  
Color Intensity ◽  
Cell Wall Components ◽  
Interesting Approach ◽  
Wall Components ◽  
Wall Interactions

The interactions between tannins and soluble and insoluble cell wall components are, in part, responsible for the low quantities of tannins found in wines compared with the quantities in grapes. The use of polysaccharides to compete with cell wall components could be an interesting approach for improving the chromatic and sensory characteristics of wines. The effect of two commercial polysaccharides, pectin and mannan, on limiting tannin-cell wall interactions was studied in a model solution, measuring the concentration of tannins and polysaccharides remaining in solution after the different interactions by chromatography. The treatment was also tested in a small-scale vinification. Soluble polysaccharides were added to the must and the wines were evaluated at the end of alcoholic fermentation and after six months in the bottle. In the model solution, the commercial polysaccharides formed soluble complexes with the tannins and limited the interactions with cell wall components, with some differences between skin and seed tannins. In the case of the wines, the treatments resulted in wines with a higher color intensity and phenolic content. Sensory analysis resulted in higher scores for the wines with added polysaccharides, since the complexation of tannins with the polysaccharides increased the roundness and body of the resulting wines.

scholarly journals Beyond Antagonism: The Interaction Between Candida Species and Pseudomonas aeruginosa

2019 ◽  
Vol 5 (2) ◽  
pp. 34 ◽  
Author(s):  
Fourie ◽  
Pohl
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Future Perspectives ◽  
Factors Influencing ◽  
Acid Metabolites ◽  
Opportunistic Pathogenic ◽  
Fatty Acid Metabolites ◽  
Wall Components

There are many examples of the interaction between prokaryotes and eukaryotes. One such example is the polymicrobial colonization/infection by the various opportunistic pathogenic yeasts belonging to the genus Candida and the ubiquitous bacterium, Pseudomonas aeruginosa. Although this interaction has simplistically been characterized as antagonistic to the yeast, this review highlights the complexity of the interaction with various factors influencing both microbes. The first section deals with the interactions in vitro, looking specifically at the role of cell wall components, quorum sensing molecules, phenazines, fatty acid metabolites and competition for iron in the interaction. The second part of this review places all these interactions in the context of various infection or colonization sites, i.e., lungs, wounds, and the gastrointestinal tract. Here we see that the role of the host, as well as the methodology used to establish co-infection, are important factors, influencing the outcome of the disease. Suggested future perspectives for the study of this interaction include determining the influence of newly identified participants of the QS network of P. aeruginosa, oxylipin production by both species, as well as the genetic and phenotypic plasticity of these microbes, on the interaction and outcome of co-infection.

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