THE CHARACTERISTICS OF MOLECULAR PROCESS OF BIOTRANSFORMATION IN HEPATOPANCREAS AND GILLS ADULT PUBESCENCE SAMPLE OF RIVER DREYSSENA (DREYSSENA POLYMORPHA) UNDER ENVIRONMENTAL POLLUTION
Introduction: during the recent decades in physiological justification of xenobiotic toxicology the terrestrial animals were used as a main object in physiological justification of xenobiotic toxicology while aquatic organisms remained neglected while the mollusks which due to their attached lifestyle, filtration-based feeding type, widespread, massive scale, availability of sampling are a comfortable object for biological survey. The aim of the research was to determine formation mechanisms of response to petroleum products in hepatopancreas and gills of zebra mussel mature species and to evaluate validity of oxidative stress parameters at biological threat of industrial contaminants of aquatic environment. Methods and materials: the experiments involved adult mature Dreyssena polymorpha river bivalve mollusk living in water reservoirs challenged with xenobiotics. During 28 days the water with the experimental mollusks was contaminated with oil residuals in constant concentration of 50 mg\l. In aquariums 1\4 of water was changed twice a week. The biological material was produced by homogenization of hepatopancreas and gills. The investigation results: a reliable (P<0.05) increase of ultimate products from lipid peroxidation and enzymatic activity of antioxidant defense (catalase, enzymes superoxide dismutase (SOD), glutathione reductase, glutathione S-transferase, glutathione peroxidase) in a response to intoxication were determined. Differences oxidative stress parameters in hepatopancreas and gills of river bivalve experimental and control mollusks. A comparative analysis of antioxidant system enzymatic activity in experimental and control mollusks showed that an increase in activity of enzymes providing lower level of oxygen response compounds: catalase, enzymes superoxide dismutase, glutathione reductase in tissues of bivalve mollusks living in the environment contaminated with oil residuals are accompanied by reduced activity of glutathione S-transferase - an enzyme catalyzing utilization of inflow exogenous aromatic compounds. Conclusion: the obtained results evidence the oxidation-reduction imbalance adequately reflects the processes of biotransformation in adult mature bivalve mollusks and a higher sensitivity of hepatopacreas cells to the effect of organic xenobiotics than that of the gills. The activity of antioxidant enzymes and a level of ultimate products from lipid peroxidation - one of the oxidative stress parameters - in tissues of adult mature species of river zebra mussle indicate that the peroxide processes peculiar to oxidative stress are sharply induced in the environment polluted with organic contaminants. These parameters show a high efficacy for bioindication and biomonitoring of mollusks performance at water bioresources pollution with organic pollutants.