Effects of temperature stress on antioxidase activity and malondialdehyde in Pomacea canaliculata.
Temperature is an important environmental factor that affects the distribution of species and causes the physiological stress response of species. After being introduced into China, the invasive species, Pomacea canaliculata has become a serious pest of important agricultural crops as well as a threat to ecosystems in its invaded regions. Effects of temperature on antioxidant enzyme activities and the malondialdehyde (MDA) contents in the hepatopancreas and gill of P. canaliculata were investigated. P. canaliculata were acclimated for two weeks with temperature 25°C. After acclimation, the low and high temperature stress experiments were conducted. The temperature maintaining at 15°C was designated as low-temperature group, 36°C as high-temperature group, and 25°C as control group, with three replicates for each group. All data were analyzed and compared with one-way ANOVA and Duncan using SPSS 22.0. The results showed that the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and the malondialdehyde contents in the hepatopancreas and gill of P. canaliculata changed similarly, both increased first and then decreased under low or high temperature stress (Fig.1-8). In groups of 15°C and 36°C, CAT activity in gill and SOD activity in hepatopancreas were significant higher than in the control group after 6 h (P<0.05) and at the highest level at 48 h (P<0.01, Fig. 2, 3). The activity of GSH-Px in gill and hepatopancreas increased at 12 h and reached the highest level in both low and high temperature groups at 24 h (Fig. 5, 6). MDA contents in gill and hepatopancreas of P. canaliculata were at the highest in the group of 15°C at 24 h and group of 36°C at 12 h, respectively (Fig. 7, 8). There were no significant differences of SOD, CAT, GSH-Px activities and MDA contents between temperature treatment groups and 25°C control group at 72 h (P>0.05). Furthermore, gills appeared more sensitive to defense oxidative damages than hepatopancreas. The results suggest that temperature stimulation can activate antioxidant enzymes activities in the hepatopancreas and gill of P. canaliculata, and eliminate reactive oxygen species (ROS) induced by low and high temperature stress.