scholarly journals Phycomyces: irregular growth patterns in stage IVb sporangiophores.

1981 ◽  
Vol 77 (1) ◽  
pp. 65-75 ◽  
Author(s):  
R I Gamow ◽  
B Böttger
Keyword(s):  
Growth Rate ◽  
Cell Wall ◽  
Measurement Error ◽  
Molecular Mechanism ◽  
Growth Response ◽  
Light Stimulus ◽  
Growth Patterns ◽  
Cell Wall Synthesis ◽  
Stage Ivb ◽  
Irregular Growth

Net rotation and net elongation of a stage IVb Phycomyces growing zone were simultaneously measured minute by minute with a photographic apparatus coupled with a rotating stage. A direct correlation between a growth response and a twist response after either a light stimulus or a house stimulus was found. There were significant irregularities in growth rate in both the elongation and rotation that were not a result of measurement error; these irregularities were poorly, if at all, correlated. We believe that these fluctuations reflect the underlying molecular mechanism of cell wall synthesis.

Susceptibility of clinical isolates of Staphylococcus aureus to killing by oxacillin

1975 ◽  
Vol 21 (11) ◽  
pp. 1692-1697 ◽  
Author(s):  
Gary K. Best ◽  
Ann V. Koval ◽  
Norma H. Best
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Rate ◽  
Cell Wall ◽  
Minimal Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Bactericidal Effect ◽  
Clinical Isolates ◽  
Cell Wall Synthesis ◽  
Abnormal Growth ◽  
Killing Action

Sixty clinical isolates of Staphylococcus aureus have been screened for their relative susceptibility to the killing action of oxacillin. Only one of these strains was found to be exceptionally resistant to the bactericidal effect of this and other β-lactam antibiotics. This ability to survive oxacillin inhibition of cell wall synthesis has been called "tolerance." The characteristics of the tolerant organism, which has been designated the Evans strain, in comparison with other isolates of S. aureus indicate that this form of resistance is not apparent from the minimal inhibitory concentration, is not related to an abnormal growth rate, and can be enhanced by treatment with N-methyl-N′-nitro-N-nitrosoguanidine.

The temporal correlation of changes in apoplast pH and growth rate in maize coleoptile segments

1998 ◽  
Vol 25 (1) ◽  
pp. 21 ◽  
Author(s):  
W. S. Peters ◽  
H. Lüthen ◽  
M. Böttger ◽  
H. Felle
Keyword(s):  
Growth Rate ◽  
Cell Wall ◽  
Growth Response ◽  
Temporal Correlation ◽  
Extracellular Acidification ◽  
Spontaneous Growth ◽  
Maize Coleoptile ◽  
Shoot Tissue ◽  
Apoplast Ph ◽  
Growing Shoot

Auxin induces extracellular acidification in growing shoot tissue. The causal relationship between this process and auxin-mediated growth is debated, partly because of contradicting previous reports on the temporal correlation of auxin-induced apoplast pH-drops and growth bursts. We have simultaneously measured both parameters on the background of spontaneously occurring endogenous changes in growth rate and apoplast pH in maize coleoptile segments. Our data demonstrate good temporal correlation, during both the ‘Spontaneous Growth Response’ and the response to exogenous auxin, which is transient under the conditions chosen due to rapid auxin metabolism. We suggest that cell wall pH and growth rate are co-regulated in this organ, and that contradictions in the literature might be due to technical difficulties.

scholarly journals Unipolar peptidoglycan synthesis in the Rhizobiales requires an essential class A penicillin-binding protein

2021 ◽  
Author(s):  
Michelle A Williams ◽  
Alena Aliashkevich ◽  
Elizaveta Krol ◽  
Erkin Kuru ◽  
Jacob M Bouchier ◽  
...  
Keyword(s):  
Cell Wall ◽  
Binding Protein ◽  
Compositional Analysis ◽  
Growth Patterns ◽  
Penicillin Binding Protein ◽  
Cell Wall Synthesis ◽  
Alternative Mode ◽  
Single Class ◽  
Class A ◽  
Peptidoglycan Synthesis

Members of the Rhizobiales are polarly-growing bacteria that lack homologs of the canonical rod complex. To investigate the mechanisms underlying polar cell wall synthesis, we systematically probed the function of cell wall synthesis enzymes in the plant-pathogen Agrobacterium tumefaciens. The development of fluorescent D-amino acid dipeptide (FDAAD) probes, which are incorporated into peptidoglycan by penicillin-binding proteins in A. tumefaciens, enabled us to monitor changes in growth patterns in the mutants. Use of these fluorescent cell wall probes and peptidoglycan compositional analysis convincingly demonstrate that a single class A penicillin-binding protein is essential for polar peptidoglycan synthesis. Furthermore, we find evidence of an alternative mode of cell wall synthesis that likely requires LD-transpeptidase activity. Genetic analysis and cell wall targeting antibiotics reveal that the mechanism of unipolar growth is conserved in Sinorhizobium and Brucella. This work provides insights into unipolar peptidoglycan biosynthesis employed by the Rhizobiales during cell elongation.

scholarly journals The Effect of Hydroxylysine on Cell Wall Synthesis and Cell Stability in Streptococcus faecalis

1962 ◽  
Vol 237 (4) ◽  
pp. 1198-1202
Author(s):  
W. Grady Smith ◽  
Mary Newman ◽  
Franklin R. Leach ◽  
L.M. Henderson
Keyword(s):  
Cell Wall ◽  
Cell Wall Synthesis ◽  
Streptococcus Faecalis ◽  
Cell Stability

scholarly journals Direct Interaction of Polar Scaffolding Protein Wag31 with Nucleoid-Associated Protein Rv3852 Regulates Its Polar Localization

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1558
Author(s):  
Rajni Garg ◽  
Chinmay Anand ◽  
Sohini Ganguly ◽  
Sandhya Rao ◽  
Rinkee Verma ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Envelope ◽  
Transmembrane Helix ◽  
Ectopic Expression ◽  
Direct Interaction ◽  
Fine Tuning ◽  
Scaffolding Protein ◽  
Physical Interaction ◽  
Cell Wall Synthesis ◽  
Interaction Approach

Rv3852 is a unique nucleoid-associated protein (NAP) found exclusively in Mycobacterium tuberculosis (Mtb) and closely related species. Although annotated as H-NS, we showed previously that it is very different from H-NS in its properties and is distinct from other NAPs, anchoring to cell membrane by virtue of possessing a C-terminal transmembrane helix. Here, we investigated the role of Rv3852 in Mtb in organizing architecture or synthesis machinery of cell wall by protein–protein interaction approach. We demonstrated a direct physical interaction of Rv3852 with Wag31, an important cell shape and cell wall integrity determinant essential in Mtb. Wag31 localizes to the cell poles and possibly acts as a scaffold for cell wall synthesis proteins, resulting in polar cell growth in Mtb. Ectopic expression of Rv3852 in M. smegmatis resulted in its interaction with Wag31 orthologue DivIVAMsm. Binding of the NAP to Wag31 appears to be necessary for fine-tuning Wag31 localization to the cell poles, enabling complex cell wall synthesis in Mtb. In Rv3852 knockout background, Wag31 is mislocalized resulting in disturbed nascent peptidoglycan synthesis, suggesting that the NAP acts as a driver for localization of Wag31 to the cell poles. While this novel association between these two proteins presents one of the mechanisms to structure the elaborate multi-layered cell envelope of Mtb, it also exemplifies a new function for a NAP in mycobacteria.

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