Ontogeny of Aerobic Capacity, Lipid Metabolism and Elevated Myoglobin Concentrations in the Skeletal Muscles of Weddell Seals

University Of Texas Southwestern Medical Center, Dallas TX

Investigators

Abstract

0125475 Kanatous This project will address the temporal development of aerobic capacity, lipid metabolism and oxygen stores in the skeletal muscles of young Weddell seals relative to aspects of the cellular environment that are important in the genetic regulation of myoglobin expression during maturation. The study will collaborate with ongoing investigations of the diving and hunting behavior of free-ranging adult and subadult Weddell Seals to investigate adaptations and the genetic control of the ontogeny of enzymatic, ultra-structural, and vascular adaptations for diving that occur in the skeletal muscles of adult Weddell seals. The first objective is to characterize the developmental changes in aerobic capacity, lipid metabolism, fiber type, and myoglobin concentration and distribution using enzymatic, immuno-histochemical and myoglobin assays in newborn, newly weaned, subadult and adult seals. The second objective is to determine the molecular controls for changes in the concentration and distribution of myoglobin in skeletal muscles during maturation. Molecular techniques will be used to determine the differences in mRNA populations in the swimming muscles of the different age classes of Weddell seals. These data will identify the proteins and transcription factors that influence the ontogenetic changes in myoglobin concentration. The results will increase our understanding of both the ontogeny and molecular mechanisms by which young seals acquire the physiological adaptations necessary to become competent divers and marine predators. In addition, this study will advance our knowledge of the molecular regulation of myoglobin in skeletal muscle, which has broader applications for human medicine.