Meeting Abstract
For sessile ectotherms, fluctuations in environmental temperature are unavoidable. Yet, these changes can have deleterious effects, often resulting in reduced performance or survival for these species. For the invasive zebra mussel (Dreissena polymorpha), little is known about their thermal physiology on a cellular level. Furthermore, the majority of studies have focused on high temperature stress, even though these animals spend several months each year exposed to cold water temperatures. A recent study showed a significant increase in the activity levels of a stress protein, AMP-activated protein kinase (AMPK) during exposure to cold, but biologically relevant, water temperatures. These results were consistent for animals collected over multiple seasons and for experiments ranging from hours to weeks of cold exposure. Since AMPK activity reflects changes in metabolic processes, these results suggest cold exposure increases energy demands. However, the underlying physiological changes and cellular mechanisms are poorly understood. One possible explanation is that the processes associated with seasonal thermal acclimation, which can involve changes in biochemical reaction rates and gene expression, may be stressful. Another possible explanation is that exposure to cold water temperatures results in cellular damage, therefore increasing the metabolic demands necessary for repair. The aim of this project is to investigate this response further by (a) determining the duration of exposure necessary to elicit an increase in AMPK activity, (b) the duration of increased AMPK activity levels, (c) whether this response results in altered thermal tolerances, and (d) to measure additional cellular and molecular parameters in order to determine whether this response is associated with cellular damage.
