Induction of peroxide and superoxide protective enzymes and physiological cross-protection against peroxide killing by a superoxide generator in Vibrio harveyi.
Vibrio harveyi is a causative agent of destructive luminous vibriosis in farmed black tiger prawn (Penaeus monodon). V. harveyi peroxide and superoxide stress responses toward elevated levels of a superoxide generated by menadione were investigated. Exposure of V. harveyi to sub-lethal concentrations of menadione induced high expression of genes in both the OxyR regulon (e.g., a monofunctional catalase or KatA and an alkyl hydroperoxide reductase subunit C or AhpC), and the SoxRS regulon (e.g., a superoxide dismutase (SOD) and a glucose-6-phosphate dehydrogenase). V. harveyi expressed two detectable, differentially regulated SOD isozymes, [Mn]-SOD and [Fe]-SOD. [Fe]-SOD was expressed constitutively throughout the growth phase while [Mn]-SOD was expressed at the stationary phase and could be induced by a superoxide generator. Physiologically, pre-treatment of V. harveyi with menadione induced cross-protection against subsequent exposure to killing concentrations of H(2)O(2). This induced cross-protection required newly synthesized proteins. However, the treatment did not induce significant protection against exposures to killing concentrations of menadione itself or cross-protect against an organic hydroperoxide (tert-butyl hydroperoxide). Unexpectedly, growing V. harveyi in high-salinity media induced protection against menadione killing. This protection was independent of SOD induction. Stationary-phase cells were more resistant to menadione killing than exponential-phase cells. The induction of oxidative stress protective enzymes and stress-altered physiological responses could play a role in the survival of this bacterium in the host marine crustaceans.
Vattanaviboon
Paiboon
P
Laboratory of Biotechnology, Chulabhorn Research Institute, Lak Si, Bangkok 10210, Thailand. paiboon@tubtim.cri.or.th
Panmanee
Warunya
W
Mongkolsuk
Skorn
S
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005954:Glucosephosphate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D018869:Heat-Shock Response; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010544:Peroxidases / Q000235:genetics / Q000378:metabolism; D010545:Peroxides / Q000378:metabolism / Q000494:pharmacology; D054464:Peroxiredoxins; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014733:Vibrio / Q000187:drug effects* / Q000201:enzymology* / Q000254:growth & development / Q000502:physiology; D024483:Vitamin K 3 / Q000494:pharmacology
D001426:Bacterial Proteins; D010545:Peroxides; D014157:Transcription Factors; D013481:Superoxides; C070724:SoxR protein, Bacteria; D024483:Vitamin K 3; D005954:Glucosephosphate Dehydrogenase; D010544:Peroxidases; D054464:Peroxiredoxins; D002374:Catalase; D013482:Superoxide Dismutase