Molecular Characterization of the Acid-Inducible<i>asr</i>Gene of<i>Escherichia coli</i>and Its Role in Acid Stress Response

Šeputienė, Vaida; Motiejunas, Domantas; Suziedelis, Kestutis; Tomenius, Henrik; Normark, Staffan; Melefors, Öjar; Sužiedėlienė, Edita

doi:10.1128/jb.185.8.2475-2484.2003

Cited by 74 publications

(70 citation statements)

References 45 publications

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“…One of these genes, asnB (b0674), codes for the glutamine-dependent asparagine synthase that is required for growth under N-limiting conditions (38). The significance of the other gene, asr (b1597), which codes for a periplasmic acid shock protein (42), is not clear. For cells grown on arginine (Fig.…”

Section: Resultsmentioning

confidence: 99%

Sulfur and Nitrogen Limitation in Escherichia coli K-12: Specific Homeostatic Responses

Gyaneshwar¹,

Paliy²,

McAuliffe³

et al. 2005

J Bacteriol

101

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We determined global transcriptional responses of Escherichia coli K-12 to sulfur (S)-or nitrogen (N)-limited growth in adapted batch cultures and cultures subjected to nutrient shifts. Using two limitations helped to distinguish between nutrient-specific changes in mRNA levels and common changes related to the growth rate. Both homeostatic and slow growth responses were amplified upon shifts. This made detection of these responses more reliable and increased the number of genes that were differentially expressed. We analyzed microarray data in several ways: by determining expression changes after use of a statistical normalization algorithm, by hierarchical and k-means clustering, and by visual inspection of aligned genome images. Using these tools, we confirmed known homeostatic responses to global S limitation, which are controlled by the activators CysB and Cbl, and found that S limitation propagated into methionine metabolism, synthesis of FeS clusters, and oxidative stress. In addition, we identified several open reading frames likely to respond specifically to S availability. As predicted from the fact that the ddp operon is activated by NtrC, synthesis of cross-links between diaminopimelate residues in the murein layer was increased under N-limiting conditions, as was the proportion of tripeptides. Both of these effects may allow increased scavenging of N from the dipeptide D-alanine-D-alanine, the substrate of the Ddp system.

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Section: Resultsmentioning

confidence: 99%

Sulfur and Nitrogen Limitation in Escherichia coli K-12: Specific Homeostatic Responses

Gyaneshwar¹,

Paliy²,

McAuliffe³

et al. 2005

J Bacteriol

101

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“…This suggests that another pathway of AR might exist, but the actual inducing conditions remain obscure. A recent report has suggested the existence of one such pathway employing the asr product (24).…”

Section: Figmentioning

confidence: 99%

Characterization of EvgAS-YdeO-GadE Branched Regulatory Circuit Governing Glutamate-Dependent Acid Resistance inEscherichia coli

2004

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Escherichia coli prefers growth in neutral pH environments but can withstand extremely acidic conditions (pH 2) for long periods. Of the four E. coli systems that contribute to acid resistance, one, the glutamatedependent system, is remarkable in its efficacy and regulatory complexity. The resistance mechanism involves the intracellular consumption of protons by the glutamate decarboxylase isozymes GadA and GadB. The antiporter GadC then exports the product, ␥-aminobutyric acid, in exchange for fresh glutamate. A microarray study using overexpressed regulators uncovered evgAS and ydeO as potential regulators of gadE, now known to encode the essential activator of the gadA and gadBC genes. Examination of evgA and ydeO under normal expression conditions revealed that their products do activate gadE expression but only under specific conditions. They were important during exponential growth in acidified minimal medium containing glucose but were unnecessary for gadE expression in stationary-phase cells grown in complex medium. The response regulator EvgA activates gadE directly and indirectly via induction of the AraC-like regulator ydeO. Evidence obtained using gadE-lacZ operon fusions also revealed that GadE was autoinduced. Electrophoretic mobility shift assays indicated that EvgA, YdeO, and GadE bind to different regions upstream of gadE, indicating they all act directly at the gadE promoter. Since GadE controls the expression of numerous genes besides gadA and gadBC, the relevance of these regulatory circuits extends beyond acid resistance.

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“…In addition to these enzymes, multiple global regulators, such as H-NS, CysB, SspA, and HU (1,7,19,34,35), small RNAs (DsrA and GadY) (17,25), topoisomerase I (37), and Asr (33) have been reported to have some roles in AR, either directly or indirectly. Furthermore, some small molecules, such as indole (9) and CO 2 (38), induced AR.…”

mentioning

confidence: 99%

ATP Requirement for Acidic Resistance in Escherichia coli

et al. 2011

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ATP participates in many cellular metabolic processes as a major substrate to supply energy. Many systems for acidic resistance (AR) under extremely acidic conditions have been reported, but the role of ATP has not been examined. To clarify whether or not ATP is necessary for the AR in Escherichia coli, the AR of mutants deficient in genes for ATP biosynthesis was investigated in this study. The deletion of purA or purB, each of which encodes enzymes to produce AMP from inosinate (IMP), markedly decreased the AR. The content of ATP in these mutants decreased rapidly at pH 2.5 compared to that of the wild type. The AR was again decreased significantly by the mutation of adk, which encoded an enzyme to produce ADP from AMP. The DNA damage in the purA and purB mutants was higher than that in the wild type. These results demonstrated that metabolic processes that require ATP participate in survival under extremely acidic conditions, and that one such system is the ATP-dependent DNA repair system.Since the normal human stomach averages pH 2 for approximately 2 h after it becomes empty, to survive in the mammalian host both commensal and pathogenic enteric bacteria have resistance systems to protect themselves against acidic stress (5,32,36).Four acidic resistance (AR) systems that are induced under different conditions have been proposed for Escherichia coli (5). Acidic resistance system 1 (AR1), which is induced in cells grown to stationary phase in a moderately acidic medium, requires the sigma factor RpoS (3, 27) and the cyclic AMP receptor protein CRP (2). The underlying mechanism remains unclear. The other three systems depend on the presence of specific amino acids. The second AR system (AR2) is a glutamate-dependent system that requires two glutamate decarboxylases (GadA and GadB) and a putative glutamate/␥-aminobutyric acid (GABA) antiporter, GadC (3,8,31). AR3 is an arginine-dependent system. It is induced by low pH under anaerobic conditions, and it requires arginine decarboxylase (AdiA) and arginine/agmatine antiporter (AdiC) (6, 10). AR4 is a lysine-dependent system that requires lysine decarboxylase (CadA) and a lysine/cadaverin antiporter (CadB) (22,40).In addition to these enzymes, multiple global regulators, such as H-NS, CysB, SspA, and HU (1,7,19,34,35), small RNAs (DsrA and GadY) (17, 25), topoisomerase I (37), and Asr (33) have been reported to have some roles in AR, either directly or indirectly. Furthermore, some small molecules, such as indole (9) and CO 2 (38), induced AR. These reports have suggested that multiple metabolic processes besides amino acid decarboxylation are required for survival under acidic conditions.The maintenance of energy is required for many metabolic processes, including the biosynthesis of cellular materials, the membrane transport of ions and organic compounds, DNA repair, cell division and cell motility, and the degradation of macromolecules. E. coli has two major energy sources, ATP and the proton-motive force. The latter is generated via the respiratory chain and i...

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Molecular Characterization of the Acid-InducibleasrGene ofEscherichia coliand Its Role in Acid Stress Response

Cited by 74 publications

References 45 publications

Sulfur and Nitrogen Limitation in Escherichia coli K-12: Specific Homeostatic Responses

Sulfur and Nitrogen Limitation in Escherichia coli K-12: Specific Homeostatic Responses

Characterization of EvgAS-YdeO-GadE Branched Regulatory Circuit Governing Glutamate-Dependent Acid Resistance inEscherichia coli

ATP Requirement for Acidic Resistance in Escherichia coli

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