Acid stress responses in enterobacteria

Bearson, Shawn M.D.; Bearson, Bradley L.; Foster, John W.

doi:10.1111/j.1574-6968.1997.tb10238.x

Cited by 413 publications

(110 citation statements)

References 37 publications

(42 reference statements)

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“…S3). Amino acid decarboxylase systems are known to protect enteric pathogens from gastric acidity (Bearson et al, 1997;Bhagwat et al, 2005;Foster, 2004). In this context, growth and respiration at low pH in the presence of different amino acid pools mimicking the conditions of phagosomes needs to be examined (Alpuche Aranda et al, 1992;Rathman et al, 1996).…”

Section: Discussionmentioning

confidence: 99%

Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

et al. 2009

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We purified osmoregulated periplasmic glucans (OPGs) from Salmonella enterica serovar Typhimurium and found them to be composed of 100 % glucose with 2-linked glucose as the most abundant residue, with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. The two structural genes for OPG biosynthesis, opgG and opgH, form a bicistronic operon, and insertion of a kanamycin resistance gene cassette into this operon resulted in a strain devoid of OPGs. The opgGH mutant strain was impaired in motility and growth under low osmolarity conditions. The opgGH mutation also resulted in a 2 log increase in the LD 50 in mice compared to the wild-type strain SL1344. Inability to synthesize OPGs had no significant impact on the organism's lipopolysaccharide pattern or its ability to survive antimicrobial peptides-, detergent-, pH-and nutrient-stress conditions. We observed that the opgGH-defective strain respired at a reduced rate under acidic growth conditions (pH 5.0) and had lower ATP levels compared to the wild-type strain. These data indicate that OPGs of S. Typhimurium contribute towards mouse virulence as well as growth and motility under low osmolarity growth conditions.

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Section: Discussionmentioning

confidence: 99%

Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

et al. 2009

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“…Consequently, many food-borne pathogens have developed survival systems that protect against acidic conditions (Bearson et al, 1997;Lin et al, 1995). There are two types of acid survival systems currently described.…”

Section: Introductionmentioning

confidence: 99%

“…However, some bacteria have more effective survival mechanisms known as acid resistance (AR) systems that will protect at pH 2.5 or below. AR systems have been extensively studied in Helicobacter pylori, Salmonella typhimurium and Escherichia coli (Bearson et al, 1997;Lin et al, 1995;Pflock et al, 2006b). E. coli possesses at least three complex cellular systems involved in the regulation of cytoplasmic pH (Foster, 2004;Richard & Foster, 2003), with RpoS (also known as s S ) and CRP (cAMP receptor protein), GadABC and AdiAC (amino acid decarboxylases and cognate antiporters) playing key roles in these systems.…”

Section: Introductionmentioning

confidence: 99%

OmpR positively regulates urease expression to enhance acid survival of Yersinia pseudotuberculosis

Wang

et al. 2009

Microbiology

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Yersinia pseudotuberculosis is an enteric bacterium which must overcome the acidic stress in host organs for successful colonization, but how this bacterium survives in acidic conditions remains largely unknown. In the present study, the importance of OmpR in acid survival of Y. pseudotuberculosis YpIII was confirmed by the fact that mutation of ompR (strain ΔompR) greatly reduced cell survival at pH 4.5 or lower. To characterize the regulatory role of OmpR in this acid survival process, proteomic analysis was carried out to compare YpIII at pH 7.0 and pH 4.5 with ΔompR at pH 7.0, and urease components were revealed to be the main targets for OmpR regulation. Addition of urea to the culture medium also enhanced acid survival of YpIII but not ΔompR and urease activity was significantly induced by acid in YpIII but not in ΔompR. Each of the seven components of the YpIII urease gene cluster was fused to a lacZ reporter and their expression was dramatically decreased in a ΔompR background; this supports the notion that OmpR positively regulates urease expression. Furthermore, gel shift analysis revealed that OmpR binds to the deduced promoter regions of three polycistronic transcriptional units (ureABC, ureEF and ureGD) in the urease cluster, suggesting that the regulation of OmpR to urease components is direct. Taken together, these data strongly suggest that OmpR activates urease expression to enhance acid survival in Y. pseudotuberculosis.

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“…Depending on the species, bacteria can induce several systems to counteract a drop in the internal pH when encountering low pH stress. Among others, these include proton pumps, several decarboxylases (lysine, glutamate, and arginine), the production of urease, arginine deiminase, chaperones (e.g., DnaK and GroELS), and sigma factor (SigB, SigM, and RpoS)-mediated responses (5,6,14,31,67). However, the importance of low-pH stress response systems in weak-acid resistance development remains unclear.…”

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confidence: 99%

Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

et al. 2008

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The weak organic acid sorbic acid is a commonly used food preservative, as it inhibits the growth of bacteria, yeasts, and molds. We have used genome-wide transcriptional profiling of Bacillus subtilis cells during mild sorbic acid stress to reveal the growth-inhibitory activity of this preservative and to identify potential resistance mechanisms. Our analysis demonstrated that sorbic acid-stressed cells induce responses normally seen upon nutrient limitation. This is indicated by the strong derepression of the CcpA, CodY, and Fur regulon and the induction of tricarboxylic acid cycle genes, SigL-and SigH-mediated genes, and the stringent response. Intriguingly, these conditions did not lead to the activation of sporulation, competence, or the general stress response. The fatty acid biosynthesis (fab) genes and BkdR-regulated genes are upregulated, which may indicate plasma membrane remodeling. This was further supported by the reduced sensitivity toward the fab inhibitor cerulenin upon sorbic acid stress. We are the first to present a comprehensive analysis of the transcriptional response of B. subtilis to sorbic acid stress.

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Acid stress responses in enterobacteria

Cited by 413 publications

References 37 publications

Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

OmpR positively regulates urease expression to enhance acid survival of Yersinia pseudotuberculosis

Transcriptome Analysis of Sorbic Acid-Stressed Bacillus subtilis Reveals a Nutrient Limitation Response and Indicates Plasma Membrane Remodeling

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