Stress-Based Identification and Classification of Antibacterial Agents: Second-Generation
            <i>Escherichia coli</i>
            Reporter Strains and Optimization of Detection

Shapiro, Elyse; Baneyx, François

doi:10.1128/aac.46.8.2490-2497.2002

Cited by 75 publications

(51 citation statements)

References 39 publications

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“…These results agree with our observation that the expression of G. stearothermophilus V genes protects E. coli against the toxic effects of hydrogen peroxide and diamide. This protective effect was further observed in transformed E. coli reporter strains ADA110 and ADA310 (30), which exhibited important reductions of ␤-galactosidase activity when exposed to K 2 TeO 3 . The levels of ␤-galactosidase in these E. coli ADA strains expressing Geobacillus genes were indistinguishable from those of controls grown in the absence of tellurite (Fig.…”

Section: Resultsmentioning

confidence: 71%

“…E. coli ADA strains induce the expression of the ␤-galactosidase gene when exposed to different stress conditions (30). These strains carry single-copy fusion genes consisting of the lacZ reporter gene fused to the promoter regions of the highly inducible cytoplasmic small heat shock proteins IbpA and IbpB (ADA110), the major cold shock protein CspA (ADA310), the P3 promoter of the rpoH gene (activated upon periplasmic protein misfolding) (ADA410), or the SOS-inducible sulA promoter (ADA510) (30).…”

Section: Resultsmentioning

confidence: 99%

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Cysteine Metabolism-Related Genes and Bacterial Resistance to Potassium Tellurite

Fuentes

Castro

et al. 2007

J Bacteriol

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Tellurite exerts a deleterious effect on a number of small molecules containing sulfur moieties that have a recognized role in cellular oxidative stress. Because cysteine is involved in the biosynthesis of glutathione and other sulfur-containing compounds, we investigated the expression of Geobacillus stearothermophilus V cysteinerelated genes cobA, cysK, and iscS and Escherichia coli cysteine regulon genes under conditions that included the addition of K 2 TeO 3 to the culture medium. Results showed that cell tolerance to tellurite correlates with the expression level of the cysteine metabolic genes and that these genes are up-regulated when tellurite is present in the growth medium.Sulfur is an essential element that is required for the biosynthesis of proteins, enzyme cofactors, and other important biomolecules. In bacteria, this element can be assimilated into sulfur-containing amino acids through enzymatic fixation from inorganic sources, such as sulfate and/or thiosulfate (15, 38). Although tellurium shares several chemical properties with sulfur, no biological function for Te is known to date. Conversely, some tellurium compounds, like the oxyanion tellurite (TeO 3 2Ϫ ), are extremely toxic for most forms of life, especially microorganisms (34).It has been proposed that K 2 TeO 3 toxicity could be due to the oxidation of cellular thiols such as glutathione (37) or the generation of superoxide radical during tellurite reduction, which would cause a redox imbalance resulting in intracellular oxidative stress (5,23,26,33,34,36).Maintenance of cell redox balance is one of the most important processes involving molecules synthesized from reduced sulfur taken from the environment. Glutathione (GSH) is one of the major nonprotein thiols in living organisms, including humans, yeast, and bacteria (6, 10). GSH has been involved in resistance to osmotic and oxidative stress as well as in Escherichia coli resistance to the toxic effects of electrophiles like methylglyoxal (6,11,31). A protective effect of GSH against oxidative stress has also been described for Lactococcus lactis and Rhodobacter capsulatus (17,18).Three genes involved in tellurite resistance have been described previously for the thermotolerant gram-positive rod Geobacillus stearothermophilus V (27, 33, 41). The genes that are involved in the metabolism of cysteine are cysK, iscS, and cobA, and they encode a cysteine synthase (CysK), a cysteine desulfurase (IscS), and a uroporphyrinogen-III C-methyltransferase (SUMT), respectively. CysK catalyzes the last step of inorganic sulfur fixation into L-cysteine, while SUMT is involved in the biosynthesis of siroheme, an essential sulfite reductase cofactor that participates in the inorganic assimilation of sulfur (15). We recently demonstrated that cobA and ubiE genes from G. stearothermophilus V confer increased tolerance to oxyanions of selenium and tellurium when expressed in E. coli (1, 32). Finally, IscS, which yields sulfur and L-alanine from L-cysteine, has been shown to be involved, along with IscA ...

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Section: Resultsmentioning

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Cysteine Metabolism-Related Genes and Bacterial Resistance to Potassium Tellurite

Fuentes

Castro

et al. 2007

J Bacteriol

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“…Activation of oxidative stress-inducible promoters by potassium tellurite supports this assumption. Recent results from our laboratory have shown that tellurite-mediated induction of the ibpA gene promoter, a gene related with oxidative response (39,40), is blocked by yqhD overexpression. Similar findings were not observed with other stress-responsive promoters not related to oxidative stress as cspA, p3RpoH, and sulA.…”

Section: Figure 3 Oxidized Proteins In E Coli a Sds-page Showing mentioning

confidence: 98%

Escherichia coli YqhD Exhibits Aldehyde Reductase Activity and Protects from the Harmful Effect of Lipid Peroxidation-derived Aldehydes

Pérez¹,

Arenas²,

Pradenas³

et al. 2008

Journal of Biological Chemistry

154

135

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Evidence that Escherichia coli YqhD is involved in bacterial response to compounds that generate membrane lipid peroxidation is presented. Overexpression of yqhD results in increased resistance to the reactive oxygen species-generating compounds hydrogen peroxide, paraquat, chromate, and potassium tellurite. Increased tolerance was also observed for the lipid peroxidation-derived aldehydes butanaldehyde, propanaldehyde, acrolein, and malondialdehyde and the membrane-peroxidizing compound tert-butylhydroperoxide. Expression of yqhD was also associated with changes in the concentration of intracellular peroxides and cytoplasmic protein carbonyl content and with a reduction in intracellular acrolein levels. When compared with the wild type strain, an yqhD mutant exhibited a sensitive phenotype to all these compounds and also augmented levels of thiobarbituric acid-reactive substances, which may indicate an increased level of lipid peroxidation. Purified YqhD catalyzes the in vitro reduction of acetaldehyde, malondialdehyde, propanaldehyde, butanaldehyde, and acrolein in a NADPH-dependent reaction. Finally, yqhD transcription was induced in cells that had been exposed to conditions favoring lipid peroxidation. Taken together these results indicate that this enzyme may have a physiological function by protecting the cell against the toxic effect of aldehydes derived from lipid oxidation. We speculate that in Escherichia coli YqhD is part of a glutathione-independent, NADPH-dependent response mechanism to lipid peroxidation.

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“…Because of their sensitivity to SOS system-inducing conditions (24), lon mutants usually present an increased sensitivity to quinolones (23,38). The spontaneous lon1::IS186 mutant AB1899 has been reported to present increased resistance to multiple antibiotics compared to its parental strain, AB1157 (Table 3) (32).…”

Section: Vol 188 2006 New Mutations Conferring a Mar Phenotype 4417mentioning

confidence: 99%

Role for Tandem Duplication and Lon Protease in AcrAB-TolC- Dependent Multiple Antibiotic Resistance (Mar) in an Escherichia coli Mutant without Mutations in marRAB or acrRAB

Nicoloff¹,

Perreten²,

McMurry³

et al. 2006

J Bacteriol

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A spontaneous mutant (M113) of Escherichia coli AG100 with an unstable multiple antibiotic resistance (Mar) phenotype was isolated in the presence of tetracycline. Two mutations were found: an insertion in the promoter of lon (lon3::IS186) that occurred first and a subsequent large tandem duplication, dupIS186, bearing the genes acrAB and extending from the lon3::IS186 to another IS186 present 149 kb away from lon. The decreased amount of Lon protease increased the amount of MarA by stabilization of the basal quantities of MarA produced, which in turn increased the amount of multidrug effux pump AcrAB-TolC. However, in a mutant carrying only a lon mutation, the overproduced pump mediated little, if any, increased multidrug resistance, indicating that the Lon protease was required for the function of the pump. This requirement was only partial since resistance was mediated when amounts of AcrAB in a lon mutant were further increased by a second mutation. In M113, amplification of acrAB on the duplication led to increased amounts of AcrAB and multidrug resistance. Spontaneous gene duplication represents a new mechanism for mediating multidrug resistance in E. coli through AcrAB-TolC.Emergence of antibiotic resistance among bacteria can be achieved by horizontal acquisition of resistance genes or by mutations of chromosomal loci. In the environment, most of the interactions between bacteria and antibacterial agents probably occur at low concentrations of drugs that favor the selection of chromosomal mutations which mediate low-level drug resistance.In Escherichia coli, the marRAB operon codes for two transcriptional regulators: MarR represses the transcription of the operon, whereas MarA positively regulates marRAB (8,19). In the presence of various inducers, some of which (such as 2,4-dinitrophenol [DNP] and sodium salicylate) directly interact with and inactivate MarR (1, 37), overexpression of marRAB occurs. Once produced, MarA can increase or decrease (directly or indirectly) the transcription of 60 to 80 genes of the mar regulon (6, 33), resulting in decreased amounts of OmpF porin and increased amounts of the AcrAB-TolC multidrug efflux pump. Reduction in membrane permeability and increase in drug export lead to resistance to multiple antibiotics and other antimicrobial compounds such as dyes, detergents, organic solvents, and oxidative stress agents (2,26,31,44), referred to as the multiple antibiotic resistance (Mar) phenotype. Overexpression of SoxS and Rob proteins also leads to increased antibiotic resistance by up-regulating marRAB and a set of genes that resembles the mar regulon (3,7,15,25,33).All mutations conferring a spontaneous Mar phenotype heretofore have been found within the marRAB, soxRS, and acrRAB loci among laboratory (8,16,25) and clinical (18, 30, 42, 43) isolates of E. coli.We now describe an overproduction of MarA and a multidrug resistance phenotype resulting from novel mutations found in a spontaneous E. coli mutant selected in the presence of a low concentration of tetracycline. MAT...

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Stress-Based Identification and Classification of Antibacterial Agents: Second-Generation Escherichia coli Reporter Strains and Optimization of Detection

Cited by 75 publications

References 39 publications

Cysteine Metabolism-Related Genes and Bacterial Resistance to Potassium Tellurite

Cysteine Metabolism-Related Genes and Bacterial Resistance to Potassium Tellurite

Escherichia coli YqhD Exhibits Aldehyde Reductase Activity and Protects from the Harmful Effect of Lipid Peroxidation-derived Aldehydes

Role for Tandem Duplication and Lon Protease in AcrAB-TolC- Dependent Multiple Antibiotic Resistance (Mar) in an Escherichia coli Mutant without Mutations in marRAB or acrRAB

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