Unusual adaptive, cross protection responses and growth phase resistance against peroxide killing in a bacterial shrimp pathogen, Vibrio harveyi

Abstract

Oxidant induced protection against peroxide killing was investigated in a prawn bacterial pathogen, Vibrio harveyi. Exposure to 250 μM H2O2induced adaptive protection against subsequent exposure to killing concentrations of H2O2. In addition, 200 μM t-butyl hydroperoxide (tBOOH) induced cross protection to H2O2killing. On the other hand, peroxide pretreatment did not induce protection against tBOOH killing. Peroxide induced adaptive and cross protection responses required new protein synthesis and were abolished by addition of a protein synthesis inhibitor. Pretreatments of V. harveyi with 250 μM H2O2and 200 μM tBOOH induced an increase in peroxide scavenging enzymes, catalase and alkyl hydroperoxide reductase subunit C. In addition, stationary phase cells of V. harveyi were more resistant to H2O2and iodoacetamide killing but highly susceptible to tBOOH killing compared to exponential phase cells. Many aspects of the oxidative stress response of V. harveyi are different from those of other bacteria and these factors may be important for bacterial survival in the environment and during interactions with host shrimp. © 2001 Published by Eslevier Science B.V. on behalf of the Federation of European Microbiological Societies.