Meeting Abstract

P1.136  Friday, Jan. 4  Thermal acclimation of locomotor performance in the Eastern Newt. MINEO, P.M.*; SCHAEFFER, P.J.; Miami University ; Miami University mineopm@muohio.edu

Biochemical acclimation to temperature is evident in some amphibians; for example, previous studies demonstrated biochemical acclimation of oxidative enzymes in muscle of the Eastern Newt (Notophthalmus viridescens). However, the degree to which this response is associated with locomotor performance is uncertain. Our goal is to determine how the acclimation of these metabolic enzymes is correlated with the thermal sensitivity of locomotor performance. We measured the burst-swimming speed and the endurance capacity of warm (25°C) and cold (5°C) acclimated newts at 5°C, 10°C, 15°C, 20°C, 25°C and 30°C. The thermal sensitivity of burst swimming speed differed between cold acclimated and warm acclimated newts such that cold acclimated newts swam faster than warm acclimated newts at the lower assay temperatures (5°C-20°C). The thermal sensitivity of endurance capacity was also different between warm and cold acclimated newts. Cold acclimated newts performed better at the lower temperatures (5°C-15°C), whereas the warm acclimated newts performed better at higher temperatures (25°C-30°C). The activities of creatine kinase, lactate dehydrogenase, citrate synthase, and cytochrome c oxidase in muscle extracted from these animals was measured across the same temperature range as the locomotor tests to determine if thermal sensitivity of enzyme function is matched with the thermal sensitivity of burst and endurance locomotion, as well as whether phenotypic flexibility of enzyme function is associated with phenotypic flexibility of locomotor performance.