Cholera is a waterborne diarrheal disease caused by Vibrio cholerae strains of serogroups O1 and O139. Expression of the general stress response regulator RpoS and formation of biofilm communities enhance the capacity of V. cholerae to persist in aquatic environments. The transition of V. cholerae between free-swimming (planktonic) and biofilm life-styles is regulated by the second messenger cy...

The yjbEFGH operon is implicated in the production of an exopolysaccharide of an unknown function and is induced by osmotic stress and negatively regulated by the general stress response sigma factor RpoS. Despite the obvious importance of RpoS, negative selection for rpoS has been reported to take place in starved cultures, suggesting an adaptive occurrence allowing the overexpression of RpoD-...

The homolog of the chromosomally encoded stationary-phase sigma factor RpoS in Borrelia burgdorferi was inactivated using gyrB(r) as a selectable marker. Two-dimensional nonequilibrium pH gradient electrophoresis of stationary-phase cell lysates identified at least 11 differences between the protein profiles of the rpoS mutant and wild-type organisms. Wild-type B. burgdorferi had a growth phase...

The bgl promoter is silent in wild-type Escherichia coli under standard laboratory conditions, and as a result, cells exhibit a beta-glucoside-negative (Bgl-) phenotype. Silencing is brought about by negative elements that flank the promoter and include DNA structural elements and sequences that interact with the nucleoid-associated protein H-NS. Mutations that confer a Bgl+ phenotype arise spo...

The rpoS-encoded sS subunit of RNA polymerase regulates the expression of stationary phase and stress response genes in Escherichia coli. Recent study of our DNA microarray analysis suggested that the rpoS expression is aŠected by multiple two-component systems. In this study, we identiˆed two-component-system mutants in which the rpoS expression increased. The regulatory manner of the systems ...

The rpoS gene encodes the sigma factor which was identified in several gram-negative bacteria as a central regulator during stationary phase. rpoS gene regulation is known to respond to cell density, showing higher expression in stationary phase. For Pseudomonas aeruginosa, it has been demonstrated that the cell-density-dependent regulation response known as quorum sensing interacts with this r...

The bacterial sigma factor RpoS is strongly induced under a variety of stress conditions and during growth into stationary phase. Here, we used rpoS-lac fusions in Escherichia coli to investigate control acting at the level of RpoS synthesis, which is especially evident when cells approach stationary phase in rich medium. Previous work has shown that the small molecule ppGpp is required for nor...

The master regulator of stationary phase in Escherichia coli, RpoS, responds to carbon availability through changes in stability, but the individual steps in the pathway are unknown. Here we systematically block key steps of glycolysis and the citric acid cycle and monitor the effect on RpoS degradation in vivo. Nutrient upshifts trigger RpoS degradation independently of protein synthesis by ac...

The ability of Escherichia coli to survive stress during growth in different environments is, in large part, dependent on rpoS and the genes that comprise the rpoS regulon. E. coli BJ4 and an isogenic BJ4 rpoS mutant were used to examine the influence of the rpoS gene on E. coli colonization of the streptomycin-treated mouse large intestine. Colonization experiments in which the wild-type E. co...

RpoS, the master sigma factor during stationary phase and under a variety of stress conditions, is regulated at multiple levels, including regulated degradation. Degradation is dependent upon ClpXP and the RssB adaptor protein. H-NS, a nucleoid-associated protein, affects the regulated degradation of RpoS; in the absence of H-NS, RpoS is stable. The mechanisms involved in this regulation were n...