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. 2002 Jul;184(13):3699-703.
doi: 10.1128/JB.184.13.3699-3703.2002.

Toxic waste disposal in Escherichia coli

Robert B Helling  1 , Brian K Janes, Heather Kimball, Timothy Tran, Michael Bundesmann, Pietra Check, Darcy Phelan, Charles Miller
Affiliations

Toxic waste disposal in Escherichia coli

Robert B Helling et al. J Bacteriol. 2002 Jul.

Abstract

About 10% of the nalidixic acid-resistant (Nal(r)) mutants in a transposition-induced library exhibited a growth factor requirement as the result of cysH, icdA, metE, or purB mutation. Resistance in all of these mutants required a functional AcrAB-TolC efflux pump, but the EmrAB-TolC pump played no obvious role. Transcription of acrAB was increased in each type of Nal(r) mutant. In the icdA and purB mutants, each of the known signaling pathways appeared to be used in activating the AcrAB-TolC pump. The metabolites that accumulate upstream of the blocks caused by the mutations are hypothesized to increase the levels of the AcrAB-TolC pump, thereby removing nalidixic acid from the organism.

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Figures

FIG. 1.
FIG. 1.
Structures of nalidixic acid and possible acrAB inducers.
FIG. 2.
FIG. 2.
Role of the AcrAB-TolC efflux pump and its activating pathways in the development of resistance of icdA mutants to nalidixic acid. •, icdA RH1854; ▪, wild-type (RH1854); ▾, ΔacrAB (RBH1855); ○, icdA ΔacrAB (icdA RBH1855). Other strains are derivatives of icdA RBH1854. Additional mutations are marA (▴), rob (▿), soxS (□), mar sox (⋄), and rob sox (▵).
FIG. 3.
FIG. 3.
Increased acrAB transcription in Nalr mutants. β-Galactosidase activity from the acrAB-lacZ fusion in different mutants or after different treatments is expressed relative to that in the wild-type organism. Standard error bars are shown, except for the lactose or nalidixic acid additions, which show the results from single experiments.
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References

    1. Alekshun, M. N., and S. B. Levy. 1999. Alteration of the repressor activity of MarR, the negative regulator of the Escherichia coli marRAB locus, by multiple chemicals in vitro. J. Bacteriol. 181:4669-4672. - PMC - PubMed
    1. Alekshun, M. N., and S. B. Levy. 1999. The mar regulon: multiple resistance to antibiotics and other toxic chemicals. Trends Microbiol. 7:410-413. - PubMed
    1. Alekshun, M. N., S. B. Levy, T. R. Mealy, B. A. Seaton, and J. F. Head. 2001. The crystal structure of MarR, a regulator of multiple antibiotic resistance, at 2.3 A resolution. Nat. Struct. Biol. 8:710-714. - PubMed
    1. Aono, R., N. Tsukagoshi, and M. Yamamoto. 1998. Involvement of outer membrane protein TolC, a possible member of the mar-sox regulon, in maintenance and improvement of organic solvent tolerance of Escherichia coli K-12. J. Bacteriol. 180:938-944. - PMC - PubMed
    1. Ariza, R. R., Z. Li, N. Ringstad, and B. Demple. 1995. Activation of multiple antibiotic resistance and binding of stress-inducible promoters by Escherichia coli Rob protein. J. Bacteriol. 177:1655-1661. - PMC - PubMed

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