title: The roles of peroxide protective regulons in protecting Xanthomonas campestris pv. campestris from sodium hypochlorite stress.
abstract: The exposure of Xanthomonas campestris pv. campestris to sublethal concentrations of a sodium hypochlorite (NaOCl) solution induced the expression of genes that encode peroxide scavenging enzymes within the OxyR and OhrR regulons. Sensitivity testing in various X. campestris mutants indicated that oxyR, katA, katG, ahpC, and ohr contributed to protection against NaOCl killing. The pretreatment of X. campestris cultures with oxidants, such as hydrogen peroxide (H2O2), t-butyl hydroperoxide, and the superoxide generator menadione, protected the bacteria from lethal concentrations of NaOCl in an OxyR-dependent manner. Treating the bacteria with a low concentration of NaOCl resulted in the adaptive protection from NaOCl killing and also provided cross-protection from H2O2 killing. Taken together, the results suggest that the toxicity of NaOCl is partially mediated by the generation of peroxides and other reactive oxygen species that are removed by primary peroxide scavenging enzymes, such as catalases and AhpC, as a part of an overall strategy that protects the bacteria from the lethal effects of NaOCl.
authors.affiliation: Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand.
authors.forename: Nisanart
authors.initials: N
authors.lastname: Charoenlap
authors.forename: Phornphan
authors.initials: P
authors.lastname: Sornchuer
authors.forename: Anong
authors.initials: A
authors.lastname: Piwkam
authors.forename: Kriangsuk
authors.initials: K
authors.lastname: Srijaruskul
authors.forename: Skorn
authors.initials: S
authors.lastname: Mongkolsuk
authors.forename: Paiboon
authors.initials: P
authors.lastname: Vattanaviboon
mesh_terms: D002374:Catalase / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology; D010545:Peroxides / Q000378:metabolism*; D018085:Regulon; D012973:Sodium Hypochlorite / Q000494:pharmacology*; D016959:Xanthomonas campestris / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism
chemical_list: D010545:Peroxides; D006861:Hydrogen Peroxide; D012973:Sodium Hypochlorite; D002374:Catalase
keywords: AhpC; OxyR; Xanthomonas; catalase–peroxidase; catalase–peroxydase; hypochlorite; katA; katG