| Summary: | Thesis (M.S.) University of Alaska Fairbanks, 2011 Increases in mitochondrial density during cold acclimation have been documented in many fish species, however the mechanism regulating this process is not understood. The present study sought to characterize metabolic changes in response to cold acclimation and identify how these changes are regulated in oxidative muscle, glycolytic muscle and liver tissue of threespine stickleback, Gasterosteus aculeatus. Fish were warm (20°C) or cold (8°C) acclimated for 9 weeks and harvested during acclimation. Mitochondrial volume density was quantified using transmission electron microscopy and aerobic metabolic capacity assessed by measuring the maximal activity of citrate synthase and cytochrome c oxidase. The molecular mechanism mediating changes in aerobic metabolic capacity were assessed by quantifying transcript levels of aerobic metabolic genes and known regulators of mammalian mitochondrial biogenesis using quantitative real-time PCR. Our results indicate that while the maximal activity of aerobic metabolic enzymes increased in all tissues, mitochondrial biogenesis only occurred in oxidative muscle. Our results also suggest that the time course of metabolic remodeling is tissue specific. Lastly, we identified differences in the magnitude and timing of transcriptional and co-transcriptional activators driving metabolic remodeling between each tissue. These results suggest aerobic metabolic remodeling may be triggered by different stimuli in different tissues. Ahtna Heritage Foundation, Ahtna Corporation, Chitina Native Corporation, Alaska Natives in Science and Engineering Program (ANSEP), Alfred P. Sloan Foundation and the Alaska INBRE program 1. Introduction -- 2. Materials and methods -- 2.1. Animals -- 2.2. Measurements of cell size and ultrastructural characteristics -- 2.3. Enzyme activity -- 2.4. RNA isolation -- 2.5. Gene expression -- 2.6. Analysis of housekeeping genes -- 2.7. Mitochondrial DNA copy number -- 2.8. Statistical analyses -- 2.9. ...
|
|---|