Special guest to discuss biology of hibernation

Nipissing’s Masters of Environmental Science Studies and the Department of Biology and Chemistry proudly present Dr. Jim Staples from Western University to campus for a special presentation titled, Fast in, S l o w  o u t:  Patterns and Mechanisms of Mitochondrial Metabolic Suppression in Hibernation, on March 22 at 1 p.m. in room R308.For most mammals, winter presents an energetic challenge; they must generate metabolic heat at high rates in order to maintain high body temperatures. This high rate of metabolism requires large quantities of food, but food is usually scarce in winter. Some small mammals avoid this challenge by adopting the strategy of hibernation wherein metabolic rate is decreased by >90% and body temperature falls close to freezing. Succinate oxidation by mitochondria isolated from liver and skeletal of hibernating ground squirrels is downregulated by 70% and 35%, respectively, when compared with summer control animals. Upon arousal from a bout of torpor this mitochondrial metabolic suppression is reversed, but only gradually. However during entrance into torpor succinate oxidation is maximally suppressed rapidly, before body temperature falls from 37oC to 30oC. This “fast in, slow out” pattern suggests a temperature-sensitive mechanism for acutely altering mitochondrial metabolism. Neither membrane remodeling nor metabolite inhibition of succinate dehydrogenase can fully account for this pattern. We hypothesize that post-translational modification of mitochondrial proteins, perhaps by phosphorylation or acetylation allows for rapid and reversible suppression of mitochondrial metabolism. Indeed our preliminary data show differential phosphorylation of some mitochondrial proteins, but the significance of these results requires further clarification.
This event is free of charge and all are welcome. Refreshments will be served.