Meeting Abstract

P1.92  Jan. 4  Effects of temperature acclimation on oxidative capacities and antioxidant enzymes in selected tissues from killifish, Fundulus heteroclitus GRIM, J.M.*; MILES, D.R.B.; CROCKETT, E.L.; Ohio University; Ohio University; Ohio University

Changes in lipid composition coupled with an expansion of oxidative capacities may leave biological membranes at an elevated risk of lipid peroxidation at low temperatures. These physiological changes could necessitate an enhancement of antioxidant defenses. Our study compares oxidative capacities, responses of enzymatic antioxidants and total antioxidant potential in muscle tissues from killifish, Fundulus heteroclitus acclimated to 5 and 25 °C for 9 days. Oxidative capacities, as indicated by cytochrome c oxidase (CCO) and citrate synthase (CS), and the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were assayed from axial glycolytic muscle and heart ventricles at 15°C. Total antioxidant potential was quantified using the radical cation ABTS assay. Oxidative capacities are generally higher in cold-acclimated fish; activities of CS in glycolytic muscle and CCO in heart are respectively1.6-fold and 2.7-fold higher in 5°C-acclimated animals. Tissues show comparable trends in activities of antioxidant enzymes, with activities generally higher in fish acclimated to 25°C. CAT activities increase with warm acclimation by more than 2-fold and 1.3-fold in heart and glycolytic muscle, respectively. Total antioxidant potentials and activities of SOD are similar in all tissues for 5°C and 25°C-acclimated fish. These data indicate that in spite of an increase in oxidative capacity at cold temperatures, no concomitant increases in activities of antioxidant enzymes or total antioxidant potential are observed. Supported by the Ohio University Research Committee, the Mount Desert Island Biological Laboratory, and the Ohio University Honors Tutorial College.