Molecular responses of the bivalve mollusks from the cooling pond as a model for prediction of contemporary environmental challenges

Abstract

To reveal a potential combined effect of pollution and continuos warming towards freshwater organisms, the molecular responses of stress and toxicity were compared du ring two years in the bivalve mollusks Anodonta anatina from the cooling pond of Khmel nytskyi Nuclear Power Plant (Ngroup) and from the ponds in the forestry (Fgroup) and agricultural (A-group) areas. Using Classification and Regression Tree (CART) software on the basis of a set of studied markers, characteristics for the distinguishing of Ngroup were selected. Firstly, it was the constantly elevated level of the vitellogeninlike protein in gonads and hemolymph of male specimens that witness the effect of endocrine dis ruption. The mussels of Ngroup demonstrated on oxidative injury with highest values of the Index of interseasonal variability for oxidized glutathione and metallothioneinrelated thiols among three groups, and constantly high level of apoptotic activity in the digestive gland. Remarkably higher levels of copper and cadmium within the tissues were detected in the N-group reflecting the industrial pollution. These metals were preferentially bound to metalbuffering protein metallothionein. A combination of these characteristics demon strates that stable elevated temperature jointly with industrial pollution caused a partial apoptotic elimination of cells with the nuclear lesions and provoked the exceeding of resistance of stressrelated responses and reproductionrelated functions in the mussels.