A one kb portion of the rpoS gene from Flexibacter chinensis was isolated by PCR, sequenced and compared to the rpoS gene of a variety of other organisms. The gene was found to be 98% similar to previously sequenced genes. Mutation of the rpoS gene with tri-parental mating produced strain JR101 and the growth rate of the mutant was compared with that of the wild-type. The mutant grew slower, an...

Regulated degradation of RpoS requires RssB and ClpXP protease. Mutations in hns increase both RpoS synthesis and stability, causing a twofold increase in synthesis and almost complete stabilization of RpoS, independent of effects on synthesis and independent of phosphorylation of RssB. This suggests that H-NS regulates an RssB inhibitor or inhibitors.

Co-ordinated regulation of gene expression is required for the transmission and survival of Borrelia burgdorferi in different hosts. The sigma factor RpoS (sigma(S)), as regulated by RpoN (sigma(54)), has been shown to regulate key virulence factors (e.g. OspC) required for these processes. As important, multiple signals (e.g. temperature, pH, cell density, oxygen) have been shown to increase t...

BACKGROUND Since the RpoN-RpoS regulatory network was revealed in the Lyme disease spirochete Borrelia burgdorferi a decade ago, both upstream and downstream of the pathway have been intensively investigated. While significant progress has been made into understanding of how the network is regulated, most notably, discovering a relationship of the network with Rrp2 and BosR, only three crucial ...

RpoS is a bacterial sigma factor of RNA polymerase which is involved in the expression of a large number of genes to facilitate survival under starvation conditions and other stresses. The results of our study demonstrate that the frequency of emergence of base substitution mutants is significantly increased in long-term-starved populations of rpoS-deficient Pseudomonas putida cells. The increa...

Understanding mechanisms of bacterial pathogenesis is critical for infectious disease control and treatment. Infection is a sophisticated process that requires the participation of global regulators to coordinate expression of not only genes coding for virulence factors but also those involved in other physiological processes, such as stress response and metabolic flux, to adapt to host environ...

The vast majority of live attenuated typhoid vaccines are constructed from the Salmonella enterica serovar Typhi strain Ty2, which is devoid of a functioning alternative sigma factor, RpoS, due to the presence of a frameshift mutation. RpoS is a specialized sigma factor that plays an important role in the general stress response of a number of Gram-negative organisms, including Salmonella. Prev...

In a proteomic analysis of rpoS-deficient Vibrio vulnificus versus the wild type, one of the down-regulated proteins in the rpoS mutant strain was identified as a Fur protein, a ferric uptake regulator. The expression of a fur::luxAB fusion was significantly influenced by sigma factor S, the rpoS gene product, and positively regulated by Fur under iron-limited conditions.

Geobacter sulfurreducens RpoS sigma factor was shown to contribute to survival in stationary phase and upon oxygen exposure. Furthermore, a mutation in rpoS decreased the rate of reduction of insoluble Fe(III) but not of soluble forms of iron. This study suggests that RpoS plays a role in regulating metabolism of Geobacter under suboptimal conditions in subsurface environments.

Vibrio cholerae is a facultative intestinal pathogen that lives in aquatic environments, often in association with planktonic species. In the suckling mouse, oral inoculation with V. cholerae leads to intestinal colonization and symptoms of diarrheal disease. Results reported here indicate a role for the alternative sigma factor, RpoS, in intestinal colonization in this model of cholera. We con...