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Undergraduate Research Project Management System

Anaerobic and Aerobic Enzyme Activity in Harp and Hooded Seal Cardiac Tissue

Status Complete
Seeking Researchers No
Start Date 09/01/2008
End Date 06/30/2009
Funding Source Alaska Heart Institute Fellowships
Funding Amount
Community Partner
Related Course
Last Updated 09/25/2010 01:04AM
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Faculty
  Jennifer Burns

Student Researchers
  Nicolette Skomp

Abstract

Marine mammal physiology has been well-studied in order to understand the adaptations that allow these animals to perform at intense levels in the absence of freely available oxygen. Bradycardia, vasoconstriction, and enhanced regulation of metabolic pathways are known to assist in prolonging oxygen availability during foraging and diving activities. However, the extent to which these mechanisms are utilized varies between skeletal and cardiac tissue. For example, while myoglobin (Mb), an oxygen storage protein is elevated in all marine mammal muscle tissues, it exists at higher levels in skeletal muscle than in cardiac tissue (Bishop, ongoing AHI funded research). This is likely in response to vasoconstriction during dives, in which skeletal muscle blood supply is drastically reduced in order to maintain constant perfusion of the heart and brain. Similarly, while it is known that seals are able to sustain aerobic metabolism during deep and long dives, the levels of aerobic and anaerobic enzymes that allow such activity are much better studied in skeletal tissue as compared to cardiac tissue. Here too, differences might exist. Skeletal tissue will likely employ anaerobic respiratory pathways as the oxygenation in peripheral tissue decreases, while cardiac tissue will continue to experience constant oxygen levels, and therefore will require higher levels of aerobic enzymes. Finally, studies have shown significant differences in metabolic capacities throughout marine mammal life span. In general, there are considerable increases in metabolic sophistication with age: for example, we have previously documented that Mb levels and acid buffering capabilities are markedly lower in seal pups in comparison to adults. Lower physiological capacity in pups likely reflects neonates' low level of muscle development, which can be attributed to their young age and their low activity levels. By measuring enzyme activity in neonate cardiac tissue, we can get a better idea of the timeline of muscular metabolic development. The specific aims of this study are to measure enzymatic activity in cardiac tissue of pup and adult harp and hooded seals and compare results to that determined for skeletal muscle for the same animals. We will also compare results across species and age classes.

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