Acid Resistance in Escherichia coli

Richard, Hope; Foster, John W.

doi:10.1016/s0065-2164(03)01007-4

Cited by 146 publications

(119 citation statements)

References 45 publications

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“…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. In addition, many other genes which express metabolic enzymes, periplasmic proteins and regulators involved in AR in E. coli have also been examined by microarray and proteomic 2D-gel analyses (Blankenhorn et al, 1999;Tucker et al, 2002).…”

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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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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“…T he acidic environment of the mammalian stomach (pH [1][2][3] plays an important role not only in the digestion of food, but also as a potent natural barrier against bacterial infections (1). Some microbes, such as Escherichia coli, have evolved systems to deal with the potentially lethal effects of acid stress.…”

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confidence: 99%

“…Some microbes, such as Escherichia coli, have evolved systems to deal with the potentially lethal effects of acid stress. Response mechanisms that protect the cytosol of E. coli against acid stress include several amino acid decarboxylases which consume protons, thereby raising the intracellular pH (2). In contrast to the well-protected bacterial cytosol, however, the periplasm has a porous outer membrane.…”

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confidence: 99%

Protein refolding by pH-triggered chaperone binding and release

Tapley

Franzmann

Chakraborty

et al. 2009

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

107

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Molecular chaperones are typically either adenosine triphosphate (ATP) dependent or rely heavily on their ATP-dependent chaperone counterparts in order to promote protein folding. This presents a challenge to chaperones that are localized to ATP-deficient cellular compartments. Here we describe a mechanism by which the pHregulated acid stress chaperone HdeA is capable of independently facilitating the refolding of acid-denatured proteins in the bacterial periplasm, which lacks both ATP and ATP-dependent chaperone machines. Our results are consistent with a model in which HdeA stably binds substrates at low pH, thereby preventing their irreversible aggregation. pH neutralization subsequently triggers the slow release of substrate proteins from HdeA, keeping the concentration of aggregation-sensitive intermediates below the threshold where they begin to aggregate. This provides a straightforward and ATP-independent mechanism that allows HdeA to facilitate protein refolding. Unlike previously characterized chaperones, HdeA appears to facilitate protein folding by using a single substrate binding-release cycle. This cycle is entirely regulated by the external environment and is therefore energy-neutral for the bacteria.ATP-independent chaperone | periplasm | protein folding | stress response

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“…In enteric bacteria such as Escherichia coli, the global regulator RpoS is an important component of the acid stress response (29,72). However, other regulators, such as the PhoPQ system and the ferric uptake regulator (Fur) in Salmonella enterica serovar Typhimurium, also play a role (4,6,8,10,30,36).…”

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confidence: 99%

Identification of Campylobacter jejuni Genes Contributing to Acid Adaptation by Transcriptional Profiling and Genome-Wide Mutagenesis

Reid

Pandey

Palyada

et al. 2008

Appl Environ Microbiol

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In order to cause disease, the food-and waterborne pathogen Campylobacter jejuni must face the extreme acidity of the host stomach as well as cope with pH fluctuations in the intestine. In the present study, C. jejuni NCTC 11168 was grown under mildly acidic conditions mimicking those encountered in the intestine. The resulting transcriptional profiles revealed how this bacterium fine-tunes gene expression in response to acid stress. This adaptation involves the differential expression of respiratory pathways, the induction of genes for phosphate transport, and the repression of energy generation and intermediary metabolism genes. We also generated and screened a transposon-based mutant library to identify genes required for wild-type levels of growth under mildly acidic conditions. This screen highlighted the important role played by cell surface components (flagella, the outer membrane, capsular polysaccharides, and lipooligosaccharides) in the acid stress response of C. jejuni. Our data also revealed that a limited correlation exists between genes required for growth under acidic conditions and genes differentially expressed in response to acid. To gain a comprehensive picture of the acid stress response of C. jejuni, we merged transcriptional profiles obtained from acid-adapted cells and cells subjected to acid shock. Genes encoding the transcriptional regulator PerR and putative oxidoreductase subunits Cj0414 and Cj0415 were among the few up-regulated under both acid stress conditions. As a Cj0415 mutant was acid sensitive, it is likely that these genes are crucial to the acid stress response of C. jejuni and consequently are important for host colonization.

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Acid Resistance in Escherichia coli

Cited by 146 publications

References 45 publications

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

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

Protein refolding by pH-triggered chaperone binding and release

Identification of Campylobacter jejuni Genes Contributing to Acid Adaptation by Transcriptional Profiling and Genome-Wide Mutagenesis

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