UC Davis

Temperature stress will continue to be a major challenge for all organisms over the next century. Ectotherms in estuarine habitats are particularly susceptible to changes in temperature. Given genetic differences among populations, it is important to understand the variation in molecular changes during acclimation to and recovery from various types of temperature challenge. Threespine sticklebacks (Gasterosteus aculeatus) represent an ideal model organism to examine such questions given their phenotypic diversity and distribution throughout coastal and inland waterways of the northern hemisphere. This dissertation utilized metabolic assays in the gill and white muscle tissue, body indices and measurements, thermal tolerances, and bottom-up proteomic analysis of the liver to investigate the molecular impacts of both acute and chronic temperature stress on first generation, lab-reared progeny from two Northern California threespine stickleback populations. Both temperature and population dependent differences were apparent throughout the experiments, demonstrating unique signatures and functional variation in response to various types of temperature challenge. Analyses of individual protein abundance changes highlighted key regulatory proteins such as HSP40-B1b in acute temperature stress, while functional enrichment analyses provided insight on broader, network-level changes. This work shows that advances in proteomics can help elucidate important bioindicators, proteomic signatures, strategies, and mechanism used to overcome environmental challenge, and ultimately how molecular phenotypes contribute to evolutionary processes.