The Stationary Phase of the Bacterial Life Cycle

Kolter, Roberto; Siegele, Deborah A.; Tormo, Antonio

doi:10.1146/annurev.mi.47.100193.004231

Cited by 748 publications

(436 citation statements)

References 42 publications

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“…The rpoS-mediated activation of transcription from P1 showed cell density dependence (Fig. 2 A and C), occurring in mid-logarithmic phase rather than in stationary phase (26). Activation of transcription from the SdiAdependent P2 promoter also showed cell density dependence ( Fig.…”

Section: Resultsmentioning

confidence: 81%

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Control of cell division in Escherichia coli: regulation of transcription of ftsQA involves both rpoS and SdiA-mediated autoinduction.

Sitnikov

Schineller

Baldwin

1996

Proc. Natl. Acad. Sci. U.S.A.

151

155

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The conditioning of culture medium by the production of growth-regulatory substances is a wellestablished phenomenon with eukaryotic cells. It has recently been shown that many prokaryotes are also capable of modulating growth, and in some cases sensing cell density, by production of extracellular signaling molecules, thereby allowing single celled prokaryotes to function in some respects as multicellular organisms. As Escherichia coli shifts from exponential growth to stationary growth, many changes occur, including cell division leading to formation of short minicells and expression of numerous genes not expressed in exponential phase. An understanding of the coordination between the morphological changes associated with cell division and the physiological and metabolic changes is of fundamental importance to understanding regulation of the prokaryotic cell cycle. The ftsQA genes, which encode functions required for cell division in E. coli, are regulated by promoters Pi and P2, located upstream of the ftsQ gene. The P1 promoter is rpoSstimulated and the second, P2, is regulated by a member of the LuxR subfamily of transcriptional activators, SdiA, exhibiting features characteristic of an autoinduction (quorum sensing) mechanism. The activity of SdiA is potentiated by N-acylhomoserine lactones, which are the autoinducers of luciferase synthesis in luminous marine bacteria as well as of pathogenesis functions in several pathogenic bacteria. A compound(s) produced by E. coli itself during growth in Luria Broth stimulates transcription from P2 in an SdiA-dependent process. Another substance(s) enhances transcription of rpoS and (perhaps indirectly) offtsQA via promoter P1. It appears that this bimodal control mechanism may comprise a fail-safe system, such that transcription of the ftsQA genes may be properly regulated under a variety of different environmental and physiological conditions.

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Section: Resultsmentioning

confidence: 81%

“…Further§To whom reprint requests should be addressed at the t address. more, we demonstrate that transcription from the second ftsQA promoter is dependent on a functional rpoS gene, the product of which is a o-factor involved in regulation of genes expressed in the stationary phase (26).…”

mentioning

confidence: 66%

Control of cell division in Escherichia coli: regulation of transcription of ftsQA involves both rpoS and SdiA-mediated autoinduction.

Sitnikov

Schineller

Baldwin

1996

Proc. Natl. Acad. Sci. U.S.A.

151

155

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“…During the stress induced by sudden starvation, maintenance of an appropriate translation elongation rate seems particularly important because the protein synthesis capacity is low and the need for synthesis of proteins with functions that can help the cell overcome the starvation period is high. 94,95 In this case, the overall translation elongation rate must be limited mainly by the concentration of the particular ternary complex that contains tRNA charged with the amino acid starved for. Degradation of the unemployed tRNAs could therefore increase the accuracy of protein translation without negatively affecting the translation elongation rate, thus optimising the quality of the protein products.…”

Section: Why Degrade Trna?mentioning

confidence: 99%

Transfer RNA instability as a stress response inEscherichia coli: Rapid dynamics of the tRNA pool as a function of demand

2018

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Production of the translation apparatus of E. coli is carefully matched to the demand for protein synthesis posed by a given growth condition. For example, the fraction of RNA polymerases that transcribe rRNA and tRNA drops from 80% during rapid growth to 24% within minutes of a sudden amino acid starvation. We recently reported in Nucleic Acids Research that the tRNA pool is more dynamically regulated than previously thought. In addition to the regulation at the level of synthesis, we found that tRNAs are subject to demand-based regulation at the level of their degradation. In this point-of-view article we address the question of why this phenomenon has not previously been described. We also present data that expands on the mechanism of tRNA degradation, and we discuss the possible implications of tRNA instability for the ability of E. coli to cope with stresses that affect the translation process.

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“…In starved E. coli, condensation of the DNA into a nucleoid is correlated with the production of large amounts of histone-like proteins, and bacteria become more resistant to stresses (for a review, see ref. 9). Spermine and spermidine, for example, protect DNA from single-strand breaks produced by singlet molecular oxygen (10).…”

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confidence: 99%

5-Methylcytosine is not a mutation hot spot in nondividing Escherichia coli

Lieb¹,

Rehmat²

1997

Proc. Natl. Acad. Sci. U.S.A.

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Spontaneous deamination of 5-methylcytosine (5meC) causes hot spots of C⅐G 3 T⅐A mutations in Escherichia coli and in human cells. In E. coli, the resulting T⅐G mispairs can be corrected to C⅐G by very short patch (VSP) repair, which requires the product of gene vsr. Mutation hot spots in genes of replicating vsr ؉ bacteria are attributable to low Vsr activity. To determine the rate of deamination of 5meC and the efficiency of VSP repair in nondividing bacteria, we used kanamycin-sensitive (Kan S ) lysogens containing a kan ؊ prophage. Deamination of a 5meC in the kan ؊ gene resulted in mutation to kanamycin resistance (Kan R ). Lysogens containing a single kan ؊ prophage per bacterial genome were grown in synthetic medium with limiting amino acids and stored at 15؇C or 37؇C. In the absence of VSP repair, Kan R mutants accumulated at the rate of approximately 1.3 ؋ 10 ؊7 per bacterium per day at 37؇C. This is similar to the 5meC 3 T mutation rate reported for DNA in solution. In vsr ؉ bacteria, the Kan R accumulation rate was 3 ؋ 10 ؊9 per bacterium per day, which is not significantly higher than the rate observed when the target cytosine was unmethylated. The increase in Kan R mutants was barely detectable in vsr ؉ cultures stored at 15؇C for 4 months. It is likely that mutation hot spots at 5meC in rapidly dividing cells are attributable to insufficient time for T⅐G correction in the interval between deamination of 5meC and subsequent DNA replication. DNA synthesis occurred in bacteria starved for amino acids and this synthesis was not highly mutagenic.

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The Stationary Phase of the Bacterial Life Cycle

Cited by 748 publications

References 42 publications

Control of cell division in Escherichia coli: regulation of transcription of ftsQA involves both rpoS and SdiA-mediated autoinduction.

Control of cell division in Escherichia coli: regulation of transcription of ftsQA involves both rpoS and SdiA-mediated autoinduction.

Transfer RNA instability as a stress response inEscherichia coli: Rapid dynamics of the tRNA pool as a function of demand

5-Methylcytosine is not a mutation hot spot in nondividing Escherichia coli

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