Cell-Wall Synthesis in Dictyostelium discoideum. I. In Vitro Synthesis from Uridine Diphosphoglucose*

Biochemistry ◽  
1965 ◽  
Vol 4 (10) ◽  
pp. 2021-2027 ◽  
Author(s):  
C. Ward ◽  
B. E. Wright
Keyword(s):  
Cell Wall ◽  
Dictyostelium Discoideum ◽  
Cell Wall Synthesis ◽  
In Vitro Synthesis

scholarly journals A cell wall damage response mediated by a sensor kinase/response regulator pair enables beta-lactam tolerance

2015 ◽  
Vol 113 (2) ◽  
pp. 404-409 ◽  
Author(s):  
Tobias Dörr ◽  
Laura Alvarez ◽  
Fernanda Delgado ◽  
Brigid M. Davis ◽  
Felipe Cava ◽  
...  
Keyword(s):  
Cell Wall ◽  
Response Regulator ◽  
Cell Envelope ◽  
Normal Growth ◽  
Cell Diameter ◽  
Cell Wall Synthesis ◽  
Beta Lactam ◽  
Cell Wall Damage ◽  
A Cell

The bacterial cell wall is critical for maintenance of cell shape and survival. Following exposure to antibiotics that target enzymes required for cell wall synthesis, bacteria typically lyse. Although several cell envelope stress response systems have been well described, there is little knowledge of systems that modulate cell wall synthesis in response to cell wall damage, particularly in Gram-negative bacteria. Here we describe WigK/WigR, a histidine kinase/response regulator pair that enablesVibrio cholerae, the cholera pathogen, to survive exposure to antibiotics targeting cell wall synthesis in vitro and during infection. Unlike wild-typeV. cholerae, mutants lackingwigRfail to recover following exposure to cell-wall–acting antibiotics, and they exhibit a drastically increased cell diameter in the absence of such antibiotics. Conversely, overexpression ofwigRleads to cell slimming. Overexpression of activated WigR also results in increased expression of the full set of cell wall synthesis genes and to elevated cell wall content. WigKR-dependent expression of cell wall synthesis genes is induced by various cell-wall–acting antibiotics as well as by overexpression of an endogenous cell wall hydrolase. Thus, WigKR appears to monitor cell wall integrity and to enhance the capacity for increased cell wall production in response to damage. Taken together, these findings implicate WigKR as a regulator of cell wall synthesis that controls cell wall homeostasis in response to antibiotics and likely during normal growth as well.

Effets d'une plasmolyse prolongée sur les tubes polliniques angiospermiens en culture in vitro : étude ultrastructurale

1988 ◽  
Vol 66 (1) ◽  
pp. 108-115 ◽  
Author(s):  
Jean-Claude Pargney
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Pollen Tubes ◽  
Ultrastructural Changes ◽  
Cell Wall Synthesis ◽  
Culture In Vitro

In angiosperm plants subjected to plasmolysis, pollen tubes may undergo substantial ultrastructural changes accompanied by a gradual deterioration of those processes involved in cell syntheses. However, some tubes quickly regenerate a polysaccharide wall and thus ensure their extension. Others undergo fragmentation of their cytoplasm and a serious breakdown in processes involved in cell wall synthesis. In these extreme cases, the endoplasmic reticulum is the only compartment that is readily discernible.

scholarly journals Staphylococcus aureus Cell Wall Biosynthesis Modulates Bone Invasion and Osteomyelitis Pathogenesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Elysia A. Masters ◽  
Gowrishankar Muthukrishnan ◽  
Lananh Ho ◽  
Ann Lindley Gill ◽  
Karen L. de Mesy Bentley ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Surface Protein ◽  
Implant Loosening ◽  
Penicillin Binding Protein ◽  
Cell Wall Synthesis ◽  
Transmission Electron ◽  
Surface Adhesins

Staphylococcus aureus invasion of the osteocyte lacuno-canalicular network (OLCN) is a novel mechanism of bacterial persistence and immune evasion in chronic osteomyelitis. Previous work highlighted S. aureus cell wall transpeptidase, penicillin binding protein 4 (PBP4), and surface adhesin, S. aureus surface protein C (SasC), as critical factors for bacterial deformation and propagation through nanopores in vitro, representative of the confined canaliculi in vivo. Given these findings, we hypothesized that cell wall synthesis machinery and surface adhesins enable durotaxis- and haptotaxis-guided invasion of the OLCN, respectively. Here, we investigated select S. aureus cell wall synthesis mutants (Δpbp3, Δatl, and ΔmreC) and surface adhesin mutants (ΔclfA and ΔsasC) for nanopore propagation in vitro and osteomyelitis pathogenesis in vivo. In vitro evaluation in the microfluidic silicon membrane-canalicular array (μSiM-CA) showed pbp3, atl, clfA, and sasC deletion reduced nanopore propagation. Using a murine model for implant-associated osteomyelitis, S. aureus cell wall synthesis proteins were found to be key modulators of S. aureus osteomyelitis pathogenesis, while surface adhesins had minimal effects. Specifically, deletion of pbp3 and atl decreased septic implant loosening and S. aureus abscess formation in the medullary cavity, while deletion of surface adhesins showed no significant differences. Further, peri-implant osteolysis, osteoclast activity, and receptor activator of nuclear factor kappa-B ligand (RANKL) production were decreased following pbp3 deletion. Most notably, transmission electron microscopy (TEM) imaging of infected bone showed that pbp3 was the only gene herein associated with decreased submicron invasion of canaliculi in vivo. Together, these results demonstrate that S. aureus cell wall synthesis enzymes are critical for OLCN invasion and osteomyelitis pathogenesis in vivo.

scholarly journals MreB filaments align along greatest principal membrane curvature to orient cell wall synthesis

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Saman Hussain ◽  
Carl N Wivagg ◽  
Piotr Szwedziak ◽  
Felix Wong ◽  
Kaitlin Schaefer ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Radial Direction ◽  
Membrane Curvature ◽  
Biophysical Modeling ◽  
Cell Wall Synthesis ◽  
Peptidoglycan Synthesis ◽  
Stable Maintenance ◽  
Spherical Cells

MreB is essential for rod shape in many bacteria. Membrane-associated MreB filaments move around the rod circumference, helping to insert cell wall in the radial direction to reinforce rod shape. To understand how oriented MreB motion arises, we altered the shape of Bacillus subtilis. MreB motion is isotropic in round cells, and orientation is restored when rod shape is externally imposed. Stationary filaments orient within protoplasts, and purified MreB tubulates liposomes in vitro, orienting within tubes. Together, this demonstrates MreB orients along the greatest principal membrane curvature, a conclusion supported with biophysical modeling. We observed that spherical cells regenerate into rods in a local, self-reinforcing manner: rapidly propagating rods emerge from small bulges, exhibiting oriented MreB motion. We propose that the coupling of MreB filament alignment to shape-reinforcing peptidoglycan synthesis creates a locally-acting, self-organizing mechanism allowing the rapid establishment and stable maintenance of emergent rod shape.

scholarly journals Spatial and temporal localization of cell wall associated pili in Enterococcus faecalis

2021 ◽  
Author(s):  
Pei Yi Choo ◽  
Charles Wang ◽  
Michael VanNieuwenhze ◽  
Kimberly Kline
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Enterococcus Faecalis ◽  
General Rule ◽  
Cell Wall Synthesis ◽  
Lipid Ii ◽  
Growing Cell ◽  
Temporal Localization

Enterococcus faecalis relies upon a number of cell wall-associated proteins for virulence. One virulence factor is the sortase-assembled endocarditis and biofilm associated pilus (Ebp), an important factor for biofilm formation in vitro and in vivo. The current paradigm for sortase-assembled pilus biogenesis in Gram-positive bacteria is that the pilus sortase covalently links pilus monomers prior to recognition, while the housekeeping sortase cleaves at the LPXTG motif within the terminal pilin subunit, and subsequently attaches assembled pilus fiber to the growing cell wall at sites of new cell wall synthesis. While the cell wall anchoring mechanism and polymerization of Ebp is well characterized, less is known about the spatial and temporal deposition of this protein on the cell surface. We followed the distribution of Ebp and peptidoglycan (PG) throughout the E. faecalis cell cycle via immunofluorescence microscopy and fluorescent D-amino acids (FDAA) staining. Surprisingly, cell surface Ebp did not co-localize with newly synthesized PG. Instead, surface-anchored Ebp was localized to the cell hemisphere but never at the septum where new cell wall is deposited. In addition, the older hemisphere of the E. faecalis diplococcus were completely saturated with Ebp, while Ebp appeared as two foci directly adjacent to the nascent septum in the newer hemisphere. A similar localization pattern was observed for another cell wall anchored substrate by sortase A, aggregation substance (AS), suggesting that this may be a general rule for all SrtA substrates in E. faecalis. When cell wall synthesis was inhibited by ramoplanin, an antibiotic that binds and sequesters lipid II cell wall precursors, new Ebp deposition at the cell surface was not disrupted. These data suggest an alternative paradigm for sortase substrate deposition in E. faecalis, in which Ebp are anchored directly onto un-crosslinked cell wall, independent of new PG synthesis.

scholarly journals Analysis of cell wall synthesis and metabolism during early germination of Blumeria graminis f. sp. hordei conidial cells induced in vitro

2019 ◽  
Vol 5 ◽  
pp. 100030 ◽  
Author(s):  
Trang A.T. Pham ◽  
Julian G. Schwerdt ◽  
Neil J. Shirley ◽  
Xiaohui Xing ◽  
Yves S.Y. Hsieh ◽  
...  
Keyword(s):  
Cell Wall ◽  
Blumeria Graminis ◽  
Cell Wall Synthesis ◽  
Early Germination
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