The role of mitochondria in mediating or moderating disturbances in oxidative metabolism

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My research program is focused on investigating metabolism to better understand how environmental stressors can impact wild fish with a focus on mitochondrial processes. To achieve this aim, my work follows 3 main themes that separate along differing levels of biological organization; from 1) in vitro development of mechanistic linkages among mitochondrial processes to 2) laboratory experiments linking whole animal responses with mitochondrial function and 3) examination of wild fish from the Experimental Lakes Area (IISD-ELA). ******Theme 1 will focus on mitochondrial control of hydrogen peroxide levels. Mitochondria are often blamed as a primary source of reactive oxygen species (ROS), the overproduction of which can lead to oxidative stress. This theme will use isolated mitochondria as the primary study system starting with representative endotherms (rodents) and then expanding to include representative ectotherms to evaluate if my lab's current model of mitochondria as regulators of ROS may have broad phylogenetic and physiological relevance. ******Theme 2 will evaluate the relationship between cellular oxidative metabolism and individual variation in responses to thermal challenge. This will combine hypotheses linking oxidative stress with elevated growth, mitochondrial efficiency and metabolic rate and the detrimental impacts of heat challenge. The study will involve fish of the genus Salvelinus (for example brook and lake trout), which are native to well-oxygenated, cold waters and may be particularly prone to the negative impacts of warming. Under conditions of thermal challenge, growth dynamics of individual fish will be evaluated to test if larger individuals have a lower tolerance to heat challenge. Metabolic and physiological performance will be evaluated as well and used to validate markers for application in Theme 3.******Theme 3 will test for non-lethal means of monitoring metabolic limitation or disruption in wild fishes. This theme will examine how local ecosystem and environmental features impact wild fish metabolism. Lake Trout populate several small lakes in the IISD-ELA that are not interconnected, creating isolated populations. However, the lake environments vary substantial across the ELA, particularly due to fluctuation in temperature and oxygen availability. Using the methodology developed form themes 1 and 2, this theme will integrate metabolic data from the whole animal, mitochondrial function assays (validated in Theme 2) and the molecular level (oxidative stress) to determine if metabolic disruption correlates with these alterations in life-history traits in wild fish. ******The proposed program would contribute to the training of at least 10 highly qualified personnel from the PhD to undergraduate level. These trainees will develop skills ranging from biochemical analysis to the design and implementation of field-based physiological experiments. **