Journal Article

Induction of peroxide and superoxide protective enzymes and physiological cross-protection against peroxide killing by a superoxide generator in <i>Vibrio harveyi</i>

Paiboon Vattanaviboon, Warunya Panmanee and Skorn Mongkolsuk

in FEMS Microbiology Letters

Volume 221, issue 1, pages 89-95
Published in print April 2003 |
Published online January 2006 | e-ISSN: 1574-6968 | DOI: http://dx.doi.org/10.1016/S0378-1097(03)00172-1

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Abstract

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 H2O2. 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.

Keywords: Catalase; Menadione; Superoxide dismutase; Superoxide; Oxidative response; Vibrio harveyi

Journal Article.  3838 words.  Illustrated.

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