Meeting Abstract
Since being introduced to the US, the invasive zebra mussel, Dreissena polymorpha, has spread rapidly and caused extensive damage by harming native species, altering water quality, and biofouling hard surfaces. Therefore, there is great interest in understanding their physiology in an attempt to limit, or at least predict, spread to new habitats. A previous experiment in our lab indicated energy imbalances are occurring during acute cold exposure. One possible explanation is that cold temperatures increased oxidative stress and impaired ATP production. While previous studies suggest reactive oxygen species increase in zebra mussels due to elevated metal concentration, high salinity, and pesticides, little is known about the links between temperature and oxidative stress in this species. The aims of this study were to determine (1) whether zebra mussels experience oxidative stress during acute thermal challenges, (2) if this response is greater due to hot or cold temperatures, and (3) if seasonal acclimation affects the response. Mussels were collected in both summer and fall and exposed to either a decrease to 10°C or increase to 30°C and held for 24 hours. Tissue was collected at various timepoints to determine superoxide dismutase (SOD) activity, total antioxidant capacity (TAC), and thiobarbituric acid reactive substances (TBARS). No significant differences were seen in the levels of TBARS. However, SOD activity was higher in fall-acclimated mussels and in mussels exposed to cold temperatures. TAC was also higher in mussels exposed to cold temperatures, suggesting that cold exposure elicits oxidative stress in zebra mussels. Ongoing analysis include quantitative real-time PCR to measure the levels of SOD and catalase as well as western blotting to measure a suite of thermal stress markers.
