Comparative analysis of CsCu/ZnSOD defense role by molecular characterization: gene expression-enzyme activity-protein level.

Cu/ZnSOD (copper/zinc superoxide dismutase) primarily scavenges cytosolic reactive oxygen species (ROS) by converting ROS to hydrogen peroxide, which is then converted to water by the catalytic action of catalase, thus playing a pivotal role in the first line of defense mechanism against oxidative stress. In this study, we have reported a complete molecular characterization of cDNA sequence from striped murrel Channa striatus (Cs). Cellular location prediction reveals that CsCu/ZnSOD protein is cytosolic with an accuracy of 90%. Phylogenetic analysis showed that CsCu/ZnSOD belongs to SOD1 group and it shared a common clad with Asian seabass Lates calcarifer and then with other fishes. The highest CsCu/ZnSOD gene expression, SOD enzyme activity and total protein concentration were observed in the liver and its regulation was studied upon fungus (Aphanomyces invadans) and bacterial (Aeromonas hydrophila) challenges. Based on the results obtained from the above analysis, we concluded a correlation of gene expression-enzyme activity-protein concentration. Overall, the findings demonstrated that the CsCu/ZnSOD plays a critical role in the antioxidant system especially in the liver during oxidative stress caused by fungus and bacteria.