Meeting Abstract

55.2  Saturday, Jan. 5  Risky Fats and Antioxidant Arsenals in Cold- and Warm-Bodied Fishes CROCKETT, E.L.; Ohio University crockett@ohiou.edu

Fishes living at cold body temperatures are rich in biological membranes that are fortified with polyunsaturated fatty acids (PUFA). PUFA are particularly susceptible to lipid peroxidation, a process initiated by reactive oxygen species (ROS) and propagated by oxidized lipids. Lipid peroxidation can damage the structure and integrity of biological membranes, and compromise the function of membrane-associated proteins. Although fishes at warmer temperatures do not contain as much lipid, or PUFA, they are confronted by higher rates of ROS production and lipid peroxidation. In our work with intracellular membranes from both temperate and Antarctic fishes, it is becoming apparent that phospholipid composition alone does not predict the inherent susceptibility of biological membranes to lipid peroxidation. Total antioxidant capacities, levels of low molecular weight antioxidants, and potential oxidants contribute to the protection against, or promotion of, oxidative injury. Activities of enzymatic antioxidants, including the family of glutathione peroxidases, are not altered with temperature acclimation. Levels of products of lipid peroxidation (e.g., phospholipid hydroperoxides) are a function of lipid quantity, more so than compositional quality. Taken together, our studies indicate that despite higher lipid contents, the risks of lipid peroxidation at low temperature are not greater than those faced by animals at warm temperatures. Fishes at cold and warm temperatures appear to require different arsenals to provide sufficient protection against lipid peroxidation. Supported by NSF IOS 0842624, ANT 0741301 and ANT 1043576.