Temperature compensation in oxidative stress and biotransformation enzyme activities in Mytilus galloprovincialis exposed to cypermethrin.

Abstract

In ectothermic organisms, as the mussel Mytilus galloprovincialis, temperature is recognized as a pervasive factor affecting structures and functions at all levels of biological organization especially at individual level or lower biological organization that has a directly influence the body temperature and cause alterations in biochemical, cellular and physiological rates. Metabolic enzyme activities are strongly affected by temperature; generally reaction rates are slower at low temperatures (Arrhenius equation). Ectotherm animals can respond, on both short-term and evolutionary time scales, to chronic temperature changes by quantitative and/or qualitative adjustments in enzyme activity. Thermal acclimation of metabolism include changes in the concentration of enzymes (quantitative strategy), maintaining the enzyme's affinity for substrate and turnover rates as temperature changes (modulation strategy), or the induction of enzymes with different kinetic properties (qualitative strategy) such as an allozyme with a lower energy of activation. In order to evaluate biochemical temperature compensation in catalase and GST activities in mussel tissues, mussels were kept at three temperatures (17ºC, 22ºC and27 °C) and two cypermethrin concentrations during 96h following a factorial design. Two widely used biomarkers of pollution Catalase (CAT) and Glutathione S-transferase (GST) were determined. Activities of each sample were measured and compared at two different conditions: at a selected common temperature of 20ºC for all them and at the acclimation temperature (17ºC, 22ºC an d27 °C). Total temperature compensation was found in catalase activity. D. Ortiz is recipient of a fellowship from PhD (Becas Chile) for Advanced Human Capital formation pertaining the Ministry of Education of Chile (CONICYT) and funded by the Government of Chile. Keywords: physiological compensation, oxidative biomarkers, Mytilus.