The Proteomic Response of Northern Elephant Seal ( Mirounga Angustirostris ) Pups to Physiological Stress During Development

• Main Author: Voisinet, Melissa P
• Format: Text
• Language: unknown
• Published: DigitalCommons@CalPoly 2019
• Subjects: Keywords: Marine Mammal; Pinnipedia; Post-weaning; Development; Energy Metabolism; Water Conservation; Diving; Cellular and Molecular Physiology; Elephant Seal; Elephant Seals
• Online Access: https://digitalcommons.calpoly.edu/theses/2536; https://doi.org/10.15368/theses.2019.136; https://digitalcommons.calpoly.edu/context/theses/article/3481/viewcontent/Voisinet_Thesis.pdf

Background: Northern elephant seals transition from terrestrial nursing pups to pelagic foraging juveniles in a short period of just 8-12 weeks. During the post-weaning period, pups rely solely on the energy reserves gained during nursing for their caloric demands and water supply. The prolonged absence of food after weaning is the first of many fasts for which the seals have evolved adaptations such as decreased urine production and increased blubber reserves. The stressors experienced from learning to dive for the first time are also stressors that they will experience frequently as an adult and for which they have evolved adaptations. The purpose of this study was to understand the tissue-specific molecular fasting- and diving- induced adaptive responses of pups during this critical transition. Methods: To investigate these adaptive responses to fasting and diving, we collected skeletal muscle and (inner and outer) adipose tissue from early-fasting (< 1 week post-weaning) and late-fasting (8 weeks post-weaning) pups. We analyzed the samples with mass-spectrometry-based proteomics using two-dimensional gel electrophoresis. Proteomics is an invaluable tool for analyzing marine mammal physiology, as it provides a large, unbiased data set of proteins that offer a comprehensive set of mechanisms involved with the cellular processes being studied. Proteomics has only been used as analytical tool for marine mammal biology in two other studies, and it can be used as a tool leading to the discovery of novel, unanticipated results. Results and Discussion: Because muscles are utilized during locomotion, we expected the proteome of skeletal muscle to highlight important physiological changes as the pups learn to dive. Inner adipose is more metabolically active than outer adipose, so we anticipated it would show important changes in metabolism throughout their fast. Outer adipose was useful to detect changes in the proteome due to thermoregulation, as it experiences the most drastic change in temperature and pressure ...