Expression of the ς ^B -Dependent General Stress Regulon Confers Multiple Stress Resistance in Bacillus subtilis

Abstract

The alternative sigma factor ςB of Bacillus subtilis is required for the induction of approximately 100 genes after the imposition of a whole range of stresses and energy limitation. In this study, we investigated the impact of a null mutation in sigB on the stress and starvation survival ofB. subtilis. sigB mutants which failed to induce the regulon following stress displayed an at least 50- to 100-fold decrease in survival of severe heat (54°C) or ethanol (9%) shock, salt (10%) stress, and acid (pH 4.3) stress, as well as freezing and desiccation, compared to the wild type. Preloading cells with ςB-dependent general stress proteins prior to growth-inhibiting stress conferred considerable protection against heat and salt. Exhaustion of glucose or phosphate induced the ςB response, but surprisingly, ςB did not seem to be required for starvation survival. Starved wild-type cells exhibited about 10-fold greater resistance to salt stress than exponentially growing cells. The data argue that the expression of ςB-dependent genes provides nonsporulated B. subtilis cells with a nonspecific multiple stress resistance that may be relevant for stress survival in the natural ecosystem.

Role of the alternative sigma factor σBonStaphylococcus aureusresistance to stresses of relevance to food preservation

“…In that regard, the most extensively studied species are Bacillus subtilis and Listeria monocytogenes (Völker et al 1999;Ferreira et al 2003;Wemekamp-Kamphuis et al 2004;Höper et al 2005). At least 100 r B -dependent stress proteins have been identified in B. subtilis, conferring protection against a variety of environmental stresses including heat, high osmolarity, high ethanol concentration, high and low pH, oxidizing agents, growth and survival under low temperatures, among others (Völker et al 1999;Höper et al 2005). Partial overlap between the r B -controlled stress responses of B. subtilis and L. monocytogenes has been demonstrated (Price 2000).…”

A connection between stress and development in the multicellular prokaryote Streptomyces coelicolor A3(2)

“…The hyphae forming these distinctivè tissues' may be subject to different environmental and metabolic stress conditions. In the unicellular bacterium, Bacillus subtilis, diverse stresses, such as heat shock, salt stress and ethanol, induce a common set of proteins, called the general stress proteins (GSPs; Hecker et al, 1996;Hecker and Vo È lker, 1998;Vo È lker et al, 1999;Price, 2000). In this organism, the general stress response is controlled by s B (Price, 2000), and the vast majority of GSP genes (.…”

“…In this organism, the general stress response is controlled by s B (Price, 2000), and the vast majority of GSP genes (. 100; Hecker et al, 1996;Vo È lker et al, 1999) are induced from s B -dependent promoters. In addition to these non-specific GSPs, each stress induces a set of specific proteins that may confer specific protection.…”

Resilience to oxidative and nitrosative stress is mediated by the stressosome, RsbP and SigB inBacillus subtilis.

“…Some sigma factors are dedicated to specific stressors, but the general stress sigma factor, SigB is responsible for the adaptation to the widest type of environmental conditions and therefore is an important protein during priming (4). Environmental conditions include high and low temperature, alkaline and acidic environments, osmotic stress and changes in carbon sources, ATP levels and oxidative stress (5-8). The activation of SigB leads to the differential expression of 196 genes with diverse biochemical functions giving cells resistance to multiple stresses, an important aspect of priming (9).…”