Differential Effect of Paraquat and Hydrogen Peroxide on the Oxidative Stress Response in<i>Vibrio Cholerae</i>Non O1 26/06

Abstract

Vibrio cholerae non O1 26/06, a non-pathogenic strain, was subjected to treatment by different concentration of paraquat (PQ) and H 2 O 2 .Exposure to PQ for 1 h caused induction of reactive oxygen species (ROS) such as superoxide anion radical ( O 2 ) and H 2 O 2 .At the same time, second stress factor significantly inhibited O 2 production and enhanced the intracellular H 2 O 2 content.The enhanced ROS generation resulted in a significant increase in the levels of oxidatively damaged proteins in comparison to the control variant.Thus, the exposure of V. cholerae cells to PQ and H 2 O 2 promoted oxidative stress.Cell response against this stress includes activation of antioxidant enzyme defence.The treatment with PQ concentrations in the range of 0 -5 mM resulted mainly in activation of SOD, but not noticeably changed CAT activity in V. cholerae non-O1 26/06.In contrast, effect of H 2 O 2 treatment on antioxidant enzyme synthesis in our Vibrio strain was still much more pronounced for CAT than for SOD.Therefore, oxidative stress responses induced by O 2 (generated intracellularly by PQ) and H 2 O 2 demonstrated differential adaptation of Vibrio cells to different toxic agents.