High concentrations of dissolved oxygen influence the composition of low molecular weight natural compounds in Lake Baikal endemic amphipods

Abstract

Lake Baikal provides a unique opportunity to study oxyphilic organisms in the focus of their adaptive abilities, and antioxidant potential. The purpose of this study was to estimate the changes in metabolic profiles and reactions of antioxidant capacities in Baikal endemic amphipods to the stress of high oxygen content. As a result of our study we have found that a high level of oxygen in the environment leads to the activation of a specific adaptive response in endemic organisms, which are naturally resistant to short-term increased concentrations of oxygen. Exposing animals to high oxygen concentrations causes both activation, i.e., use, and concurrently apparent inhibition of the synthesis of some low molecular weight natural compounds (whose specific nature is yet to be determined) in these endemic amphipods. This could be explained by the animals’ response to oxidative stress and stress-induced synthesis of natural compounds as adaptation mechanisms. At the same time, the reactions of elimination of some natural products found in metabolic profiles can be explained by the specific reduction of target metabolites or molecules neutralizing oxygen radicals and decreasing their content during exposition to current stress conditions. We also noted species-specific, stress-dependent changes in the antioxidant capacity of amphipods. Thus, the newly described mechanisms of stress resistance and newly found molecules in these endemic crustaceans can become a basis for development of new potential natural products, e.g., drugs, the action of which should be aimed at elimination or at least reduction of oxidative stress in organisms and its undesired consequences.