Meeting Abstract
Northern elephant seals (Mirounga angustirostris) have several key physiological adaptations allowing them to develop from a terrestrial nursing pup to a juvenile able to dive and forage independently in the water. During the approximately 8-week time period between the weaning of the pup and their departure to sea, juvenile seals rely solely on the energy reserves they gained during nursing for all caloric and water demands. While adult elephant seals fast during molting, mating, and lactation, pups fast while undergoing a major transition from a terrestrial to an aquatic lifestyle. The purpose of this study was to understand the fasting-induced adaptive responses of pre- and post-weaning M. angustirostris pups using a proteomics approach. We collected tissue from skeletal muscle and the inner and outer adipose layers of both pre- and post- weaning pups (n = 20). After performing first and second dimension gel electrophoresis, we then analyzed the samples using mass-spectrometry-based proteomics. Our initial analysis identified proteins which provide reducing equivalents for biosynthesis or the scavenging of reactive oxygen species (NADP isocitrate dehydrogenase), and proteins related to oxidative stress (Cu-Zn superoxide dismutase) and the cytoskeleton (gelsolin). Through ongoing analysis, we expect to identify significant increases in proteins related to metabolism (transition to beta-oxidation pathways) and oxidative stress (antioxidant proteins), and decreases in cytoskeletal proteins that aid in the development of diving ability in post-weaning pups. This study will provide important information about the adaptive capacity of marine mammals at a critical developmental stage.
