abstract soil contamination with heavy metals is a serious problem in all over the world. soils are contaminated by many different sources of heavy metals. currently different methods are used by researchers for identifying heavy metal contamination. assessing soil metal toxicity with bacterial bioluminescence is one of the new techniques. in this study, different concentrations of zinc and cop...

Copper plays a dual role as a nutrient and a toxin during bacterial infections. While uropathogenic Escherichia coli (UPEC) strains can use the copper-binding metallophore yersiniabactin (Ybt) to resist copper toxicity, Ybt also converts bioavailable copper to Cu(II)-Ybt in low-copper conditions. Although E. coli have long been considered to lack a copper import pathway, we observed Ybt-mediate...

The multicopper oxidase CueO had previously been demonstrated to exhibit phenoloxidase activity and was implicated in intrinsic copper resistance in Escherichia coli. Catecholates can potentially reduce Cu(II) to the prooxidant Cu(I). In this report we provide evidence that CueO protects E. coli cells by oxidizing enterobactin, the catechol iron siderophore of E. coli, in the presence of copper...

Numerous pathogenic microorganisms secrete small molecule chelators called siderophores defined by their ability to bind extracellular ferric iron, making it bioavailable to microbes. Recently, a siderophore produced by uropathogenic Escherichia coli, yersiniabactin, was found to also bind copper ions during human infections. The ability of yersiniabactin to protect E. coli from copper toxicity...

Escherichia coli O157:H7 is a serious pathogen causing haemorrhagic colitis. It has been responsible for several large-scale outbreaks in recent years. E. coli O157:H7 is able to survive in a range of environments, under various conditions. The risk of infection from contaminated surfaces is recognised, especially due to the low infectious dose required. In this study, a high concentration (10(...

The most notable method of infection from Escherichia coli O157 (E. coli O157) is through contaminated food products, usually ground beef. The objective of this study was to evaluate seven cast copper alloys (61 to 95% Cu) for their ability to reduce the viability of E. coli O157, mixed with or without ground beef juice, and to compare these results to those for stainless steel. E. coli O157 (N...

Using a genetic screen we have identified two chromosomal genes, cusRS (ylcA ybcZ), from Escherichia coli K-12 that encode a two-component, signal transduction system that is responsive to copper ions. This regulatory system is required for copper-induced expression of pcoE, a plasmid-borne gene from the E. coli copper resistance operon pco. The closest homologs of CusR and CusS are plasmid-bor...

Three distinct clones from a Salmonella typhimurium genomic library were identified which suppressed the copper-sensitive (Cu(s)) phenotype of cutF mutants of Escherichia coli. One of these clones, pCUTFS2, also increased the copper tolerance of cutA, -C, and -E mutants, as well as that of a lipoprotein diacylglyceryl transferase (lgt) mutant of E. coli. Characterization of pCUTFS2 revealed tha...

A gene (yacK) encoding a putative multicopper oxidase (MCO) was cloned from Escherichia coli, and the expressed enzyme was demonstrated to exhibit phenoloxidase and ferroxidase activities. The purified protein contained six copper atoms per polypeptide chain and displayed optical and electron paramagnetic resonance (EPR) spectra consistent with the presence of type 1, type 2, and type 3 copper ...

This study explores the role of membrane phospholipid peroxidation in the copper alloy mediated contact killing of Bacillus subtilis, a spore-forming gram-positive bacterial species. We found that B. subtilis endospores exhibited significant resistance to copper alloy surface killing but vegetative cells were highly sensitive to copper surface exposure. Cell death and lipid peroxidation occurre...