RRC ID 4962
Author Harrison JJ, Tremaroli V, Stan MA, Chan CS, Vacchi-Suzzi C, Heyne BJ, Parsek MR, Ceri H, Turner RJ.
Title Chromosomal antioxidant genes have metal ion-specific roles as determinants of bacterial metal tolerance.
Journal Environ. Microbiol.
Abstract Microbiological metal toxicity involves redox reactions between metal species and cellular molecules, and therefore, we hypothesized that antioxidant systems might be chromosomal determinants affecting the susceptibility of bacteria to metal toxicity. Here, survival was quantified in metal ion-exposed planktonic cultures of several Escherichia coli strains, each bearing a mutation in a gene important for redox homeostasis. This characterized approximately 250 gene-metal combinations and identified that sodA, sodB, gor, trxA, gshA, grxA and marR have distinct roles in safeguarding or sensitizing cells to different toxic metal ions (Cr(2)O(7)(2-), Co(2+), Cu(2+), Ag(+), Zn(2+), AsO(2)(-), SeO(3)(2-) or TeO(3)(2-)). To shed light on these observations, fluorescent sensors for reactive oxygen species (ROS) and reduced thiol (RSH) quantification were used to ascertain that different metal ions exert oxidative toxicity through disparate modes-of-action. These oxidative mechanisms of metal toxicity were categorized as involving ROS and thiol-disulfide chemistry together (AsO(2)(-), SeO(3)(2-)), ROS predominantly (Cu(2+), Cr(2)O(7)(2-)) or thiol-disulfide chemistry predominantly (Ag(+), Co(2+), Zn(2+), TeO(3)(2-)). Corresponding to this, promoter-luxCDABE fusions showed that toxic doses of different metal ions up- or downregulate the transcription of gene sets marking distinct pathways of cellular oxidative stress. Altogether, our findings suggest that different metal ions are lethal to cells through discrete pathways of oxidative biochemistry, and moreover, indicate that chromosomally encoded antioxidant systems may have metal ion-specific physiological roles as determinants of bacterial metal tolerance.
Volume 11(10)
Pages 2491-509
Published 2009-10
DOI 10.1111/j.1462-2920.2009.01973.x
PMID 19555372
MeSH Adaptation, Physiological / genetics* Anions / chemistry Antioxidants / metabolism Bacterial Proteins / genetics Bacterial Proteins / metabolism Cations / chemistry Chromosomes, Bacterial / genetics* Escherichia coli / chemistry Escherichia coli / genetics Escherichia coli / metabolism* Escherichia coli Proteins / genetics Escherichia coli Proteins / metabolism Gene Expression Regulation, Bacterial Genes, Bacterial* Metals / chemistry Metals / metabolism* Oxidation-Reduction Repressor Proteins / genetics Repressor Proteins / metabolism Superoxide Dismutase / genetics Superoxide Dismutase / metabolism Thioredoxins / genetics Thioredoxins / metabolism
IF 5.147
Times Cited 27
Prokaryotes E. coli ME5305(AG1) CV-25(DH5alpha) ME9062(BW25113)