Features of the Mechanisms of Antioxidant System Activation in Fresh-Water Amphipoda: II. The Baikal Littoral <i>Eulimnogammarus cyaneus</i> (Dyb.)
The goal of the work is to estimate the mechanisms of activation of the antioxidant system under the oxidative action of endogenous character in the Baikal endemic species Eulimnogammarus cyaneus (Dyb.). The oxidative action was induced by exposing the amphiрoda in the solutions of a laboratory humin-containing preparation. Experiments showed that two different mechanisms of the antioxidant system functioning can be activated in the Baikal amphiрoda of Е. cyaneus species. Depending on the conditions and duration of preliminary acclimatization, a change of the activation mechanism of antioxidant protection or its separate elements is observed. For the organisms with the duration of preliminаry acclimatization within three days, we observed the involvement of a specific mechanism allowing efficient eliminаtion of the formed ROS in the case of low concentrations of humin-containing preparation. This mechanism is characterized by the inhibition of enzymatic activity of peroxidase and glutathione-S-transferase, as well as by a decrease in the level of hydrogen peroxide. In the Baikal amphiрoda kept for a long time in an artificial environment, the oxidant action activates the mechanism of protection similar to that observed previously for the Palaearctic species. This mechanism is characterized by an increase of the enzymatic activity of peroxidase, a decrease of the activity of catalase, and the absence of inhibition of glutathione-S-transferase.