2002-2003 Science Planning Summary

Biology & Medicine

Dr. Polly Penhale
Program Manager

BO-018-O

NSF/OPP 01-25475
Station: McMurdo Station
RPSC POC: Curt LaBombard
Research Site(s): Sea ice camp

Ontogeny of aerobic capacity, lipid metabolism, and elevated myoglobin concentrations in the skeletal muscles of Weddell seals
Dr. Shane B. Kanatous
University of Texas
Internal Medicine
shane.kanatous@utsoujtwestern.edu
Dr. Randall Davis
Texas A & M University
Dept. of Marine Biology

Deploying Team Members: Shane B Kanatous . Rebecca Watson
Research Objectives: What is the temporal development of aerobic capacity, lipid metabolism, and oxygen stores in the skeletal muscles of young Weddell seals, and which aspects of the cellular environment are important in the genetic regulation of myoglobin expression during maturation? This group will address this broad question during a 2-year study that will collaborate with Randall Davisí ongoing study (BO-017) of the diving and hunting behavior of free-ranging adult and subadult Weddell seals. Results from the previous collaboration characterized the enzymatic, ultrastructural, and vascular adaptations for diving that occur in the skeletal muscles of adult Weddell seals. This study builds on those results to investigate the ontogeny of these adaptations and the genetic control of their development.

The first objective is to characterize the ontogenetic changes in aerobic capacity, lipid metabolism, fiber type, and myoglobin concentration and distribution using enzymatic, immunohistochemical, 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. Through subtractive hybridization and subsequent analysis, researchers will determine the differences in mRNA populations in the swimming muscles of the different age classes of Weddell seals. These techniques will allow researchers to identify the proteins and transcription factors that influence 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 they need 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. The collaboration with research on the diving and hunting behavior of Weddell seals will enhance the results of both studies, minimize the number of adult animals handled, share personnel, and reduce the need for additional logistical support.


Field Season Overview:
Sharing a field camp with Randall Davis' group (BO-017-O), project team members will travel on snowmobiles and tracked vehicles to nautral cracks in the sea ice. Using a purse-seine net they will capture adult male and non-pregnant female Weddell seals and transport them to the field camp.