title: Protective roles of katG-homologous genes against extrinsic peroxides in Vibrio parahaemolyticus.
abstract: The marine foodborne enteropathogen, Vibrio parahaemolyticus, has four putative catalase genes. Function of the katG-homologous genes, katG1(VPA0768) and katG2(VPA0453), was examined using gene deletion mutants, and compared with those of the katE-homologous genes, katE1(VPA1418) and katE2(VPA0305). Bacterial growth of ΔkatG1 was significantly delayed in the presence of 200-300 μM H2O2, and such inhibition was enhanced when incubation temperature was lowered from 37°C to 22°C. In the stationary phase, the ΔkatG1 strain was more susceptible to the lethal dosage of H2O2 than the ΔkatE1 strain. The minimum inhibitory concentrations and minimum bactericidal concentrations revealed that ΔkatE1/ΔkatE2 strains were more susceptible to H2O2 than the ΔkatG1/ΔkatG2 strains in exponential phase, while ΔkatG1 was more susceptible than the ΔkatE1/ΔkatE2 strains in the starved culture. This study demonstrated the chief antioxidative role of katG1 in the stationary phase and starved culture of V. parahaemolyticus, while katG1 and katG2 were also responsive to H2O2 and cumene hydroperoxide in the exponential phase.
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China.
authors.forename: Shu-Chuan
authors.initials: SC
authors.lastname: Yu
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China.
authors.forename: Shin-yuan
authors.initials: SY
authors.lastname: Fen
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China.
authors.forename: Cheng-Lun
authors.initials: CL
authors.lastname: Chien
authors.affiliation: Department of Microbiology, Soochow University, Taipei, Taiwan 111, Republic of China wonghc@scu.edu.tw.
authors.forename: Hin-chung
authors.initials: HC
authors.lastname: Wong
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D002374:Catalase / Q000235:genetics*; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D050296:Microbial Viability / Q000187:drug effects / Q000235:genetics; D018384:Oxidative Stress; D010545:Peroxides / Q000494:pharmacology*; D017384:Sequence Deletion; D014736:Vibrio parahaemolyticus / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development
chemical_list: D001426:Bacterial Proteins; D010545:Peroxides; D006861:Hydrogen Peroxide; D002374:Catalase
keywords: KatG; Vibrio parahaemolyticus; catalase; hydrogen peroxide; oxidative stress; starvation; stationary phase