scholarly journals Mutations in a single signaling pathway allow growth on a different solvent than water

2019 ◽  
Author(s):  
Caroline Kampmeyer ◽  
Jens V. Johansen ◽  
Christian Holmberg ◽  
Magnus Karlson ◽  
Sarah K. Gersing ◽  
...  
Keyword(s):  
Cell Wall ◽  
Morphological Changes ◽  
Biological Effects ◽  
Control Cell ◽  
Wall Material ◽  
Cell Integrity ◽  
Prolonged Incubation ◽  
Altered Glucose ◽  
Wide Range ◽  
The Impact

AbstractSince life is completely dependent on water, it is difficult to gauge the impact of solvent change. To analyze the role of water as a solvent in biology, we replaced water with heavy water (D2O), and investigated the biological effects by a wide range of techniques, using the fission yeast Schizosaccharomyces pombe as model organism. We show that high concentrations of D2O lead to altered glucose metabolism, growth retardation, and inhibition of meiosis. However, mitosis and overall cell viability were only slightly affected. After prolonged incubation in D2O, cells displayed gross morphological changes, thickened cell walls as well as aberrant septa and cytoskeletal organization. RNA sequencing revealed that D2O causes a strong downregulation of most tRNAs and triggers activation of the general stress response pathway. Genetic screens identified several D2O sensitive mutants, while mutants compromised in the cell integrity pathway, including the protein kinase genes pmk1, mkh1, pek1 and pck2, that control cell wall biogenesis, were more tolerant to D2O. We speculate that D2O affects the phospholipid membrane or cell wall glycans causing an activation of the cell integrity pathway. In conclusion, the effects of solvent replacement are pleiotropic but the D2O-triggered activation of the cell integrity pathway and subsequent increased deposition of cell wall material and septation problems appear most critical for the cell growth defects.

The impact of chemical structure on polyphenol bioaccessibility, as a function of processing, cell wall material and pH: A model system

2021 ◽  
Vol 289 ◽  
pp. 110304 ◽  
Author(s):  
Eden Eran Nagar ◽  
Liora Berenshtein ◽  
Inbal Hanuka Katz ◽  
Uri Lesmes ◽  
Zoya Okun ◽  
...  
Keyword(s):  
Cell Wall ◽  
Chemical Structure ◽  
Model System ◽  
Wall Material ◽  
Cell Wall Material ◽  
The Impact

scholarly journals (472) Yeast Expressed Tomato β-Galactosidases 1, 4, and 5 Have Activity against Synthetic and Plant-derived Cell Wall Substrates

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1092B-1092 ◽  
Author(s):  
Megumi Ishimaru ◽  
David L. Smith ◽  
Kenneth C. Gross
Keyword(s):  
Cell Wall ◽  
Tomato Fruit ◽  
Wall Material ◽  
Wall Structure ◽  
Fruit Softening ◽  
Pectic Polysaccharides ◽  
Wide Range ◽  
Fruit Pericarp ◽  
Galactosyl Residues

Fruit softening occurs by several mechanisms, including modifications of cell wall structure by wall degrading enzymes. The most prominent change in tomato fruit pericarp wall composition is the loss of galactosyl residues throughout development and especially during ripening. In order to understand the role of galactosyl turnover in fruit softening, we successfully produced three recombinant tomato β-galactosidase/exo-galactanase (TBG) fusion proteins in yeast. TBG1, 4 and 5 enzyme properties and substrate specificities were assessed. Optimum pH of TBG1, 4 and 5 was 5.0, 4.0, and 4.5 and optimum temperature was 40∼50, 40, and 40 °C, respectively. The K ms for TBG1, 4 and 5 were 7.99, 0.09, and 2.42 mm, respectively, using p-nitrophenyl-β-D-galactopyranoside as substrate. Using synthetic and plant-derived substrates, TBG1 and 5 released galactosyl residues from 1 → 4 linkages. TBG4 released galactosyl residues from a wide range of plant-derived oligosaccharides and polysaccharides. Using tomato fruit cell wall material, TBG1, TBG4 and TBG5 released galactosyl residues from a variety of fruit stages and cell wall fractions. TBG4 released the most galactosyl residues from the ASP fraction and especially the ASP fraction from fruit at the turning stage. Interestingly, even though walls from Turning fruit stage contain less total galactosyl residues than at the Mature Green stage, TBG4 released 3–4 fold more galactose from the CSP and ASP fractions from Turning fruit. These results suggest that changes in structure of wall pectic polysaccharides leading up to the Turning stage may cause the wall to become more susceptible to hydrolysis by the TBG4 product.

Ultrastructural changes in the myxamoebae of Physarum polycephalum in response to a microcyst-inducing concentration of mannitol

1984 ◽  
Vol 62 (2) ◽  
pp. 272-280 ◽  
Author(s):  
Lynda M. Williams ◽  
Jean-G. Lafontaine
Keyword(s):  
Cell Wall ◽  
Osmotic Potential ◽  
Physarum Polycephalum ◽  
Morphological Changes ◽  
Ruthenium Red ◽  
Ultrastructural Changes ◽  
Wall Material ◽  
Cell Wall Material ◽  
Cell Coat ◽  
Ruthenium Red Staining

The response of axenically cultured Physarum polycephalum myxamoebae to a microcyst-inducing concentration of mannitol (0.5 M) has been studied for both log-phase and maximum-concentration cultures. Results indicate that mannitol alone is not sufficient to induce encystment; a population effect is also necessary. Myxamoebae may continue to divide in the presence of mannitol if this effect is absent. Early ultrastructural changes have been noted indicating that the primary mode of action of mannitol is via the change in osmotic potential of the medium. Nuclear and cytoplasmic ultrastructural changes during the encystment process are documented. Recovery of log-phase cells to undergo mitosis involves definite morphological changes, which are also described. Ruthenium red staining was utilised to emphasize changes in the cell coat and indicate possible sites of accumulation of cell wall material.

scholarly journals Cell wall material strain hardening on dynamic responses of closed-cell foams

2017 ◽  
Vol 24 (6) ◽  
pp. 883-892 ◽  
Author(s):  
Jianjun Zhang ◽  
Zhihua Wang ◽  
Longmao Zhao
Keyword(s):  
Cell Wall ◽  
Energy Dissipation ◽  
Strain Hardening ◽  
Deformation Mode ◽  
Dynamic Responses ◽  
Wall Material ◽  
Cell Wall Material ◽  
Plastic Energy ◽  
Closed Cell ◽  
The Impact

AbstractThe paper focuses on the effects of the cell wall material strain hardening on the mechanical behavior of closed-cell foams subjected to the constant velocity loading. Three-dimensional Voronoi models were established to present the closed-cell foams, and the simulations were performed by employing Ls-dyna 971. The investigation found that the cell wall strain hardening could postpone the onset of the localized collapse bands and retard deformation mode transformation. Strain hardening convergence phenomenon was observed in the closed-cell foams; increasing the impact velocity could weaken the effect of the material strain hardening. The crushing stress at both impact and stationary sides were analyzed in detail. The material strain hardening could always enhance the plastic energy dissipation. Furthermore, the strain hardening convergence was also observed in the plateau stress at the impact side and plastic energy dissipation but not in the densification strain and the plateau at the stationary side.

scholarly journals Impact of LytR-CpsA-Psr Proteins on Cell Wall Biosynthesis in Corynebacterium glutamicum

2016 ◽  
Vol 198 (22) ◽  
pp. 3045-3059 ◽  
Author(s):  
Meike Baumgart ◽  
Karin Schubert ◽  
Marc Bramkamp ◽  
Julia Frunzke
Keyword(s):  
Cell Wall ◽  
Mycobacterium Tuberculosis ◽  
Corynebacterium Glutamicum ◽  
Morphological Changes ◽  
Cell Wall Biosynthesis ◽  
Special Focus ◽  
Content Type ◽  
Cell Wall Biogenesis ◽  
Exact Function ◽  
The Impact

ABSTRACT Proteins of the LCP (LytR, CpsA, Psr) family have been shown to inherit important roles in bacterial cell wall biosynthesis. However, their exact function in the formation of the complex cell wall structures of the Corynebacteriales , including the prominent pathogens Mycobacterium tuberculosis and Corynebacterium diphtheriae , remains unclear. Here, we analyzed the role of the LCP proteins LcpA and LcpB of Corynebacterium glutamicum , both of which localize at regions of nascent cell wall biosynthesis. A strain lacking lcpB did not show any growth-related or morphological phenotype under the tested conditions. In contrast, conditional silencing of the essential lcpA gene resulted in severe growth defects and drastic morphological changes. Compared to the wild-type cell wall, the cell wall of this mutant contained significantly less mycolic acids and a reduced amount of arabinogalactan. In particular, rhamnose, a specific sugar component of the linker that connects arabinogalactan and peptidoglycan, was decreased. Complementation studies of the lcpA -silencing strain with several mutated and truncated LcpA variants suggested that both periplasmic domains are essential for function whereas the cytoplasmic N-terminal part is dispensable. Successful complementation experiments with proteins of M. tuberculosis and C. diphtheriae revealed a conserved function of LCP proteins in these species. Finally, pyrophosphatase activity of LcpA was shown in an in vitro assay. Taken together, our results suggest that LCP proteins are responsible for the transfer of arabinogalactan onto peptidoglycan in actinobacterial species and support a crucial function of a so-far-uncharacterized C-terminal domain (LytR_C domain) which is frequently found at the C terminus of the LCP domain in this prokaryotic phylum. IMPORTANCE About one-third of the world's population is infected with Mycobacterium tuberculosis , and multiple-antibiotic resistance provokes the demand for novel antibiotics. The special cell wall architecture of Corynebacteriales is critical for treatments because it is either a direct target or a barrier that the drug has to cross. Here, we present the analysis of LcpA and LcpB of the closely related Corynebacterium glutamicum , the first of which is an essential protein involved in cell wall biogenesis. Our work provides a comprehensive characterization of the impact of LCP proteins on cell wall biogenesis in this medically and biotechnologically important class of bacteria. Special focus is set on the two periplasmic LcpA domains and their contributions to physiological function.

Binding of heterocyclic amines by lactic acid bacteria from miso, a fermented Japanese food

1998 ◽  
Vol 44 (2) ◽  
pp. 109-115 ◽  
Author(s):  
Rajam Rajendran ◽  
Yoshiyuki Ohta
Keyword(s):  
Cell Wall ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Binding Activity ◽  
Fermented Food ◽  
Heterocyclic Amines ◽  
Wall Material ◽  
Bromocresol Purple ◽  
Bacterial Cells ◽  
The Impact

Miso, a widely used Japanese fermented food was analysed for its lactic acid bacterial count on bromocresol purple agar. The binding of eight different foodborne carcinogenic heterocyclic amines to 25 bacterial isolates from miso were investigated. The heterocyclic amines used were 3-amino-1,4-dimethyl[5H]pyrido(4,3-b)indole (Trp-P-1), 3-amino-1-methyl[5H]pyrido(4,3-b)indole (Trp-P-2), 2-amino-6-methyldipyrido(1,2-a:3'2'-d)imidazole (Glu-P-1), 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), 2-amino-dimethylimidazo(4,5f)quinoline (IQ), 2-amino-3,4-dimethylimidazo(4,5-f) quinoline (MeIQ), 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx), and 2-amino-3-methyl-9H-pyrido(2,3)indole (MeAαC). The lyophilized cells of all of the isolates exhibited high binding activity towards Trp-P-1, Trp-P-2, MeAαC, and PhIP, while Glu-P-1 and IQ were not effectively bound. Of the isolates tested, the strongest and weakest binders were identified as Pediococcus acidilactici 1 and 2, respectively. Lyophilized cell wall fractions, heat-treated cells, and the cytoplasmic contents of P. acidilactici 1 and 2 were analysed for their ability to bind to different mutagens. Pure cell wall and peptidoglycan showed greater binding activity than the bacterial cells. Cytoplasmic content also showed some binding, but it was much less effective. The impact of enzymes (amylase, protease, cellulase, chitinase, muraminase, and peptidase) and acetylation of Trp-P-1 and IQ on the binding action of bacteria and cell wall material were also analysed to understand the possible processes involved in the binding of lactic acid bacteria to carcinogenic heterocyclic amines.Key words: mutagen, heterocyclic amines, lactic acid bacteria, binding, miso.

scholarly journals Understanding Changes in Tomato Cell Walls in Roots and Fruits: The Contribution of Arbuscular Mycorrhizal Colonization

2019 ◽  
Vol 20 (2) ◽  
pp. 415 ◽  
Author(s):  
Matteo Chialva ◽  
Jonatan U. Fangel ◽  
Mara Novero ◽  
Inès Zouari ◽  
Alessandra Salvioli di Fossalunga ◽  
...  
Keyword(s):  
Cell Wall ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Cell Wall Composition ◽  
Mycorrhizal Colonization ◽  
Mineral Nutrient ◽  
Wall Material ◽  
Systemic Level ◽  
Am Symbiosis ◽  
The Impact

Modifications in cell wall composition, which can be accompanied by changes in its structure, were already reported during plant interactions with other organisms, such as the mycorrhizal fungi. Arbuscular mycorrhizal (AM) fungi are among the most widespread soil organisms that colonize the roots of land plants, where they facilitate mineral nutrient uptake from the soil in exchange for plant-assimilated carbon. In AM symbiosis, the host plasma membrane invaginates and proliferates around all the developing intracellular fungal structures, and cell wall material is laid down between this membrane and the fungal cell surface. In addition, to improve host nutrition and tolerance/resistance to environmental stresses, AM symbiosis was shown to modulate fruit features. In this study, Comprehensive Microarray Polymer Profiling (CoMMP) technique was used to verify the impact of the AM symbiosis on the tomato cell wall composition both at local (root) and systemic level (fruit). Multivariate data analyses were performed on the obtained datasets looking for the effects of fertilization, inoculation with AM fungi, and the fruit ripening stage. Results allowed for the discernment of cell wall component modifications that were correlated with mycorrhizal colonization, showing a different tomato response to AM colonization and high fertilization, both at the root and the systemic level.

scholarly journals USP9X Is Required to Maintain Cell Survival in Response to High-LET Radiation

2021 ◽  
Vol 11 ◽  
Author(s):  
Catherine M. Nickson ◽  
Maria Rita Fabbrizi ◽  
Rachel J. Carter ◽  
Jonathan R. Hughes ◽  
Andrzej Kacperek ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Survival ◽  
Cell Biology ◽  
Cellular Response ◽  
Biological Effects ◽  
Control Cell ◽  
X Rays ◽  
High Let Radiation ◽  
High Let ◽  
The Impact

Ionizing radiation (IR) principally acts through induction of DNA damage that promotes cell death, although the biological effects of IR are more broad ranging. In fact, the impact of IR of higher-linear energy transfer (LET) on cell biology is generally not well understood. Critically, therefore, the cellular enzymes and mechanisms responsible for enhancing cell survival following high-LET IR are unclear. To this effect, we have recently performed siRNA screening to identify deubiquitylating enzymes that control cell survival specifically in response to high-LET α-particles and protons, in comparison to low-LET X-rays and protons. From this screening, we have now thoroughly validated that depletion of the ubiquitin-specific protease 9X (USP9X) in HeLa and oropharyngeal squamous cell carcinoma (UMSCC74A) cells using small interfering RNA (siRNA), leads to significantly decreased survival of cells after high-LET radiation. We consequently investigated the mechanism through which this occurs, and demonstrate that an absence of USP9X has no impact on DNA damage repair post-irradiation nor on apoptosis, autophagy, or senescence. We discovered that USP9X is required to stabilize key proteins (CEP55 and CEP131) involved in centrosome and cilia formation and plays an important role in controlling pericentrin-rich foci, particularly in response to high-LET protons. This was also confirmed directly by demonstrating that depletion of CEP55/CEP131 led to both enhanced radiosensitivity of cells to high-LET protons and amplification of pericentrin-rich foci. Our evidence supports the importance of USP9X in maintaining centrosome function and biogenesis and which is crucial particularly in the cellular response to high-LET radiation.

scholarly journals Procyanidin—Cell Wall Interactions within Apple Matrices Decrease the Metabolization of Procyanidins by the Human Gut Microbiota and the Anti-Inflammatory Effect of the Resulting Microbial Metabolome In Vitro

Nutrients ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 664 ◽  
Author(s):  
Carine Le Bourvellec ◽  
Priscilla Bagano Vilas Boas ◽  
Pascale Lepercq ◽  
Sophie Comtet-Marre ◽  
Pauline Auffret ◽  
...  
Keyword(s):  
Cell Wall ◽  
Gut Microbiota ◽  
Biological Effects ◽  
Bioactive Metabolites ◽  
Cell Wall Polysaccharides ◽  
Covalent Bonds ◽  
The Matrix ◽  
Anti Inflammatory ◽  
The Impact

B-type oligomeric procyanidins in apples constitute an important source of polyphenols in the human diet. Their role in health is not known, although it is suggested that they generate beneficial bioactive compounds upon metabolization by the gut microbiota. During apple processing, procyanidins interact with cell-wall polysaccharides and form stable complexes. These interactions need to be taken into consideration in order to better assess the biological effects of fruit constituents. Our objectives were to evaluate the impact of these interactions on the microbial metabolization of cell walls and procyanidins, and to investigate the potential anti-inflammatory activity of the resulting metabolome, in addition to analyzing the taxonomical changes which the microbiota undergo. In vitro fermentation of three model apple matrices with microbiota from 4 healthy donors showed that the binding of procyanidins to cell-wall polysaccharides, whether covalently or non-covalently, substantially reduced procyanidin degradation. Although cell wall-unbound procyanidins negatively affected carbohydrate fermentation, they generated more hydroxyphenylvaleric acid than bound procyanidins, and increased the abundance of Adlercreutzia and Gordonibacter genera. The best results in terms of production of anti-inflammatory bioactive metabolites were observed from the apple matrix with no bonds between procyanidins and cell wall polysaccharides, although the matrix with non-covalent bonds was not far behind.

scholarly journals Paws, pads and plants: the enhanced elasticity of cell-filled load-bearing structures

2015 ◽  
Vol 471 (2178) ◽  
pp. 20150107 ◽  
Author(s):  
L. Angela Mihai ◽  
Khulud Alayyash ◽  
Alain Goriely
Keyword(s):  
Cell Wall ◽  
Elastic Modulus ◽  
Cell Walls ◽  
Large Strain ◽  
Strain Energy Function ◽  
Material Design ◽  
Wall Material ◽  
Solid Core ◽  
Internal Cell ◽  
Wide Range

Paws, fat pads and plants share a remarkable structure made up of closed cells with elastic cell walls capable of supporting large loads and deformations. A key challenge is to understand how the function of these structures is enhanced by their geometric and material design. To do so, we compare different elastic models operating in large strain deformation when the cells are empty or filled with an incompressible liquid or solid core. We demonstrate theoretically, for three different cell geometries, that the elastic modulus in a direction associated with the change of curvature in the cell wall (i) is greater when the cell is filled; (ii) increases as the internal cell pressure increases; and (iii) increases also as the thickness of the cell wall increases or when the wall is multi-layer. As these results do not depend on the choice of the strain-energy function describing the cell-wall material, they are valid for a wide range of structures made from different elastic materials. For multiple cells deforming together due to external forces, the increase in elastic modulus of the cell walls under increasing core pressure is found numerically throughout the structure.

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