The influence of growth phase and ionic environment on the dissociation of Escherichia coli ribosomes by p-chloromercuribenzoate

1968 ◽  
Vol 46 (8) ◽  
pp. 905-910 ◽  
Author(s):  
A. T. Matheson ◽  
Jerry Hsueh-Ching Wang
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Growth Phase ◽  
Sulfhydryl Groups ◽  
Ionic Environment ◽  
Presence And Absence ◽  
Escherichia Coli B

The effect of p-chloromercuribenzoate (PCMB) on the structure of polysomes and ribosomes isolated from early log phase and stationary phase cells of Escherichia coli B has been studied in the presence and absence of K+. At 0° no breakdown of polysomes was observed in the presence of 0.5 mM PCMB. The 100S dimer, however, both at 0° and 25°, was readily dissociated under all conditions tested. The dissociation of 70S particles was much more sluggish and was most apparent in ribosomes isolated from early log phase cells in buffer containing K+. These results indicate that the sulfhydryl groups involved in 100S dissociation are more accessible to PCMB than those involved in the dissociation of 70S particles.

scholarly journals Nucleoids Dynamic in Escherichia coli: A Growth Phase Dependent Process

1970 ◽  
Vol 23 (2) ◽  
pp. 81-88 ◽  
Author(s):  
Ali Azam Talukder ◽  
M Anwar Hossain ◽  
Mamoru Yamada ◽  
Akira Ishihama
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Gene Silencing ◽  
Cell Survival ◽  
Growth Phase ◽  
Genomic Dna ◽  
Bacterial Dna ◽  
Escherichia Coli Cells ◽  
Dna Organization ◽  
Nucleoid Proteins

Bacterial DNA compacts in nucleoid bodies. The organization of nucleoid body depends on the association of genomic DNA with a numbers of histone-like proteins. The relax nucleoids organization in rapidly growing Escherichia coli cells associate with six major proteins, Fis, HU, Hfq, H-NS, StpA and IHF, but at stationary phase the nucleoids further tightly pack with Dps. The final steps of compact nucleoids formation occurs with association of MukBEF complex - a bacterial condensin. The change of nucleoid proteins composition in stationary phase accompanies compact DNA organization and genes silencing. Thus, compact nucleoid organization and gene silencing may be crucial for cell survival in stationary phase.Keywords: Escherichia coli, Nucleoid body, Nucleoid proteins, Nucleoid compaction, CondensinDOI: http://dx.doi.org/10.3329/bjm.v23i2.867 Bangladesh J Microbiol, Volume 23, Number 2, December 2006, pp 81-88

scholarly journals Global Role for ClpP-Containing Proteases in Stationary-Phase Adaptation of Escherichia coli

2003 ◽  
Vol 185 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Dieter Weichart ◽  
Nadine Querfurth ◽  
Mathias Dreger ◽  
Regine Hengge-Aronis
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Growth Phase ◽  
Proteome Analysis ◽  
Resting Cells ◽  
Wild Type ◽  
Late Stationary Phase ◽  
E Coli ◽  
In The Wild ◽  
Dps Protein

ABSTRACT To elucidate the involvement of proteolysis in the regulation of stationary-phase adaptation, the clpA, clpX, and clpP protease mutants of Escherichia coli were subjected to proteome analysis during growth and during carbon starvation. For most of the growth-phase-regulated proteins detected on our gels, the clpA, clpX, or clpP mutant failed to mount the growth-phase regulation found in the wild type. For example, in the clpP and clpA mutant cultures, the Dps protein, the WrbA protein, and the periplasmic lysine-arginine-ornithine binding protein ArgT did not display the induction typical for late-stationary-phase wild-type cells. On the other hand, in the protease mutants, a number of proteins accumulated to a higher degree than in the wild type, especially in late stationary phase. The proteins affected in this manner include the LeuA, TrxB, GdhA, GlnA, and MetK proteins and alkyl hydroperoxide reductase (AhpC). These proteins may be directly degraded by ClpAP or ClpXP, respectively, or their expression could be modulated by a protease-dependent mechanism. From our data we conclude that the levels of most major growth-phase-regulated proteins in E. coli are at some point controlled by the activity of at least one of the ClpP, ClpA, and ClpX proteins. Cultures of the strains lacking functional ClpP or ClpX also displayed a more rapid loss of viability during extended stationary phase than the wild type. Therefore, regulation by proteolysis seems to be more important, especially in resting cells, than previously suspected.

scholarly journals Identification of Conserved, RpoS-Dependent Stationary-Phase Genes of Escherichia coli

1998 ◽  
Vol 180 (23) ◽  
pp. 6283-6291 ◽  
Author(s):  
Herb E. Schellhorn ◽  
Jonathon P. Audia ◽  
Linda I. C. Wei ◽  
Lily Chang
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Growth Phase ◽  
Regulatory Mechanisms ◽  
Alternative Sigma Factor ◽  
Gram Negative Bacteria ◽  
Gene Fusions ◽  
Free Living ◽  
Cellular Resistance ◽  
Regulated Functions

ABSTRACT During entry into stationary phase, many free-living, gram-negative bacteria express genes that impart cellular resistance to environmental stresses, such as oxidative stress and osmotic stress. Many genes that are required for stationary-phase adaptation are controlled by RpoS, a conserved alternative sigma factor, whose expression is, in turn, controlled by many factors. To better understand the numbers and types of genes dependent upon RpoS, we employed a genetic screen to isolate more than 100 independent RpoS-dependent gene fusions from a bank of several thousand mutants harboring random, independent promoter-lacZ operon fusion mutations. Dependence on RpoS varied from 2-fold to over 100-fold. The expression of all fusion mutations was normal in an rpoS/rpoS +merodiploid (rpoS background transformed with anrpoS-containing plasmid). Surprisingly, the expression of many RpoS-dependent genes was growth phase dependent, albeit at lower levels, even in an rpoS background, suggesting that other growth-phase-dependent regulatory mechanisms, in addition to RpoS, may control postexponential gene expression. These results are consistent with the idea that many growth-phase-regulated functions inEscherichia coli do not require RpoS for expression. The identities of the 10 most highly RpoS-dependent fusions identified in this study were determined by DNA sequence analysis. Three of the mutations mapped to otsA, katE,ecnB, and osmY—genes that have been previously shown by others to be highly RpoS dependent. The six remaining highly-RpoS-dependent fusion mutations were located in other genes, namely, gabP, yhiUV, o371,o381, f186, and o215.

scholarly journals Growth Phase-Coupled Alterations in Cell Structure and Function of Escherichia coli

2003 ◽  
Vol 185 (4) ◽  
pp. 1338-1345 ◽  
Author(s):  
Hideki Makinoshima ◽  
Shin-Ichi Aizawa ◽  
Hideo Hayashi ◽  
Takeyoshi Miki ◽  
Akiko Nishimura ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Stationary Phase ◽  
Cell Density ◽  
Growth Phase ◽  
Cell Structure ◽  
Volume Ratio ◽  
Density Increase ◽  
Electron Microscopic ◽  
Thin Sections ◽  
E Coli

ABSTRACT Escherichia coli cultures can be fractionated into more than 20 cell populations, each having a different bouyant density and apparently representing a specific stage of cell differentiation from exponential growth to stationary phase (H. Makinoshima, A. Nishimura, and A. Ishihama, Mol. Microbiol. 43:269-279, 2002). The density increase was found to be impaired at an early step for a mutant E. coli with the disrupted rpoS gene, which encodes the RNA polymerase RpoS (sigma-S) for stationary-phase gene transcription. This finding suggests that RpoS is need for the entire process of cell density increase. In the absence of RpoF sigma factor, the flagella are not formed as observed by electron microscopy, but the growth phase-coupled density increase takes place as in wild-type E. coli, confirming that the alteration in cell density is not directly correlated with the presence or absence of flagella. In the stationary-phase cells, accumulation of electron-dense areas was observed by electron microscopic observation of bacterial thin sections. By chemical determination, the increase in glycogen (or polysaccharides) was suggested to be one component, which contributes to the increase in weight-to-volume ratio of stationary-phase E. coli cells.

scholarly journals The Stationary-Phase Sigma Factor σS Is Responsible for the Resistance of Escherichia coli Stationary-Phase Cells to mazEF-Mediated Cell Death

2009 ◽  
Vol 191 (9) ◽  
pp. 3177-3182 ◽  
Author(s):  
Ilana Kolodkin-Gal ◽  
Hanna Engelberg-Kulka
Keyword(s):  
Escherichia Coli ◽  
Cell Death ◽  
Stationary Phase ◽  
Growth Phase ◽  
Sigma Factor ◽  
Stationary Growth Phase ◽  
Cellular Growth ◽  
Oxygen Species ◽  
Stationary Growth ◽  
Gene Encoding

ABSTRACT Escherichia coli mazEF is a toxin-antitoxin gene module that mediates cell death during exponential-phase cellular growth through either reactive oxygen species (ROS)-dependent or ROS-independent pathways. Here, we found that the stationary-phase sigma factor σS was responsible for the resistance to mazEF-mediated cell death during stationary growth phase. Deletion of rpoS, the gene encoding σS from the bacterial chromosome, permitted mazEF-mediated cell death during stationary growth phase.

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