[ELEMENTS OF THE LOW MOLECULAR WEIGHT CHAIN OF ANTIOXIDANT DEFENSE IN TISSUES OF THE BLACK SEA MOLLUSC ANADARA KAGOSHIMENSIS BRUGÙIERE].

The content of reduced glutathione (GSH) and the activity of the coupled with it antioxidant enzymes - glutathione peroxidase and glutathione reductase as well the level of glucose, carbamide and amino acids were investigated in the hepatopancreas, gills and foot of the Black, Sea mollusk Anadara kagoshimensis. The highest content of GSH and the highest activity of glutathione peroxidase were found in mollusk foot, evidencing the active antioxidant role of glutathione played both within composition of this enzyme and independently. The maximal content of glucose, amino acids and carbamide was in the hepatopancreas and gills and the minimal - in the anadara's foot. The possible involvement and role of these low molecular weight antioxidants in the defense of mollusk tissues against action of free radical oxidation and in providing adaptation reactions of anadara in hypoxic habitats are considered. Key words: antioxidant complex, glutathione, glucose, carbamide, amino acids, anadara Anadara kagoshimensis, Black Sea.

[The activity of transaminases in the tissues of the Black-Sea mollusk Mytilus galloprovincialis].

The activities of aspartate aminotransferase (AST, E. C. 2.6.1.1) and alanine aminotransferase (ALT, E. C. 2.6.1.2) were studied in the tissues of the bivalve mollusks differing in shell color. Shell color patterns were assessed by photographing and computer processing in Adobe Photoshop CS-3. The activity of transaminases was determined by the Reitman-Frankel procedure. Four color groups of mollusks were singled out: black, intermediate, dark- and light brown. The AST and ALT activities were found to increase as shells lose color probably reflecting different tolerance of mollusks to habitats with different concentration of oxygen. The ALT distribution pattern differs appreciably in the foot of M. galloprovincialis where the highest values were found in the black-colored mussels, evidently due to the change of the predominant enzyme function. In this tissue, the reaction of transamination replenishes the pool of free amino acids required for the synthesis of byssus threads.

[Peculiarities of organization of tissue metabolism in molluscs with different tolerance to external hypoxia].

Oxygen consumption, content of several carbohydrate metabolites, and activities of their coupled enzymes were studied in bivalve molluscs with different tolerance to oxygen deficit: Mytilus galloprovincialis Lam. (black morpha) and Anadara inaequivalvis Br. It has been shown that under conditions of external normoxia the anadara resistance to hypoxia preserves anaerobic orientation of metabolism. Its tissues are distinguished by high activities of malate and lactate dehydrogenases with the decreased content of glucose and the increased level of lactate. In several organs the succinate thiokinase and fumarate reductase reactions are realized, which is indicated by elevated activities of the alanine and aspartate aminotransferases. The anaerobic orientation of protein metabolism is added by a high pool of free aminoacids and the elevated urea content in the molluscs tissues. The total orientation of metabolism in the anadara tissues rules out a significant lactate accumulation and determines low requirements of its organism in oxygen.

[Tissue specificity of metabolism in bivalve mollusc Anadara inaequivalvis Br. under conditions of experimental anoxia].

Peculiarities of the course of metabolic processes in tissues of the bivalve mollusc Anadara inaequivalvis Br. were studied under conditions of experimental anoxia. In the absence of oxygen, in gill and foot the protein catabolism processes were found to be enhanced; this led to a decrease of the protein content and to an increase of the free amino acid and urea levels. Predominantly hydrolyzed were low molecular peptides, which was indicated by a decrease of the cathepsin D activity on the background of a rise of the gamma-glutamyltranspeptidase activity. Anoxia was accompanied by enhancement of the succinate thiokinase and fumarate reductase reactions controlled by alanine and aspartate aminotransferases. They prevented accumulation of toxic lactate in tissues and allowed obtaining an additional macroerg resource. Metabolic processes in the mollusc hepatopancreas were oriented to production of amino acids.