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Title: Low temperature protein metabolism : the energetic costs of living and growing at thermal extremes
Author: Bowgen, A. D.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2007
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To determine if evolution to polar water temperatures has altered the way in which Antarctic marine organisms adapt to changing temperature, protein metabolism, growth and ATP allocation were examined in the Antarctic teleost Harpagifer antarcticus, and compared with data from two temperate teleosts, Lipophrys pholis and Parablennius gattorugine. The energetic cost of protein synthesis in the Antarctic limpet, Nacella concinna, was similar to that measured in other non-polar ectotherms, and unaffected by acclimation temperature. The rate of protein synthesis in H. antarcticus was unaffected by temperature between -1 and +3°C, and was significantly lower than in L. pholis held at the same temperature. Growth rates in H. antarcticus were significantly lower and protein metabolism less efficient than in L. pholis. Tissue specific protein synthesis rates varied in a similar manner to that reported in other studies, while the effects of temperature were again markedly reduced in the Antarctic species when compared with the temperate species. Protein metabolism in the examined Antarctic species is considerably less efficient than in the temperate species, suggesting that slow growth rates reported in Antarctic species may not only be the result of a variable food supply, but also biochemical constraints on growth efficiency. There were significant differences in how temperature affected the oxygen consumption allocated to major hepatocyte energy consuming processes in H. antarcticus and P. gattorugine. The effects of temperature were less pronounced in H. antarcticus, however proton leak increased significantly with falling temperature in H. antarcticus, but not P. gattorugine. Increased proton leak in H.antarcticus at low temperatures may be a mechanism to reduce oxidative damage.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available