[Functional states of the antioxidant enzymatic complex of tissues of Mytilus galloprovincialis Lam. under conditions of oxidative stress].

There are generalized materials on reaction of enzymatic antioxidant (AO) complex of tissues of molluscs of the genus Mytilus to oxidative loading of different intensity. It is shown that with increase of level of oxidative stress, a rise of activity of glutathione peroxidase (GP) and glutathione reductase (GR) is observed, as well as the rate of glutathione (GSH) in tissues also increases. Then the toxic loading is compensated by a rise of activities of enzymes of low affinity to hydroperoxides, specifically of catalase. In the glutathione system, it is possible to identify several relatively steady states: of low, moderate, and highly intensive processes. In several tissues, functioning of the AO system seems to be directed not to rendering harmless, but to generation of reactive oxygen species (O2-, superoxide dismutase), which is likely to be determined by specificity of their running processes (destruction of damaged byssus theads). The molluscan AO complex is characterized by high lability and sensitivity both to physiological states (spawning) and to action of factors of anthropogenic nature (cationic detergents). Reactions of AO complex of the mussel to the natural states and to toxic action are comparable between each other, which is necessary to be taken into account at diagnostics of the aquatic medium.

[Qualitative composition of carotenoids, catalase and superoxide dismutase activities in tissues of bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789)].

By using high-performance liquid chromatography, UV-VIS-spectra and mass spectra (FAB MS) in tissues of bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789) there are identified seven kinds of carotenoids: trans- and cis-pectenolon, alloxanthin, pectenol A, beta-carotene, zeaxanthin, and diatoxanthin. Their quantitative ratio in hepatopancreas, gills, and foot of the animals was determined. There was revealed negative correlation (R2 about 0.9) between content of several carotenoids (trans- and cis-pectenolon, zeaxanthin, alloxanthin, and diatoxanthin) in tissues and activities of antioxidant enzymes (catalase and superoxide dismutase). The presence of competitive relations between these molecular systems is assumed and their underlying causes are discussed.

[Peculiarities of antioxidant defense system organization of the Black Sea mollusks Mytilus].

Antioxidant (AO) system and lipid peroxidation (LP) in tissues of two species of the Black Sea bivalve mollusks Mytilus galloprovincialis and Anadara inaequivalvis were investigated. The activity of superoxide dismutase (SOD, 1.15.1.1), catalase (1.11.1.6), glutathione peroxidase (GP, 1.11.1.9), glutathione reductase (GR, 1.6.4.2), concentrations of reduced glutathione (GSH) and TBA-reactive products were determined in the foot, hepatopancreas and gills of mature mollusks. The characteristics of AO complex and LP products connected with tissue and species specificity of mollusks were found. Hepatopancreas of mussels has been found to have higher values of all characteristics investigated, except GP. The gills and the foot of anadara have been found to be involved in AO defense along with hepatopancreas: maximum activity of GR, catalase and SOD was found in the gills and the highest activity of GP and maximum level of GSH was observed in the foot. Anadara has been shown to have higher antioxidant potential and lower level of oxidative stress because the LP intensity in all tissues examined of the hemoglobin-containing mollusk was twice lower in comparison with the mussel.

[Content of carotenoids and the state of tissue antioxidant enzymatic complex in bivalve mollusc Anadara inaequivalvis Br].

The work studied the content of carotinoids, the state of antioxidant (AO) enzymatic complex, and intensity of lipid peroxidation in tissues (hepatopancreas, gill, foot) of the Black Sea bivalve mollusc Anadara inaequivalvis. Tissues with a high content of the pigment have been established to have had a low activity of the key AO enzymes: superoxide dismutase, catalase, glutathione reductase, and an elevated content of reduced glutathione R2--(0.81-0.97). The recorded intertissue activities reached 1.7-2.9 times (p < or = 0.05-0.01). At increased concentrations (more than 2.5 mg x 100 g(-1) tissue), carotinoids show insignificant prooxidant effect, which is reflected in a rise of glutathione peroxidase activity. The competitive interrelations between these molecular complexes for the same kinds of reactive ocygem species (O2-, OH*, and 1O2) are discussed.

[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.

[State of the system of antioxidant defense in tissues of the black sea turbot during the spawning].

The system of antioxidant (AO) defense and processes of lipid peroxidation (LP) of the Black Sea turbot Psetta (Scophtalmus) maxima maeotica (L., 1758) have been investigated during the spawning season. The activity of glutathione peroxidase (GP), glutathione reductase (GR), catalase and content of reduced glutathione (GSH) and TBA-reactive products have been determined in gonads, gills, liver, red and white muscles of males and females at different stages of gonad's maturity (V and VI stages). The peculiarities of AO complex and LP depended on tissue specificity and sexual distinctions of the turbot have been found. The turbot females at VI stage were found to have the most significant changes. In gonads and liver the level of TBA-reactive products decreased. In gonads the activities of GP and GR decreased, but the level of GSH increased. In gills of these females the activity of GP and the level of GSH increased, while in the red muscles the activity of catalase raised. In white muscles the activity of GR dropped. In the males' tissues of the turbot at VI stage the growth of the activity of GP in gills and GSH content in white muscles have been found. In all tissues of males the decrease of the TBA-reactive products content has been observed.

[State of the antioxidant enzyme complex of tissues of the Black Sea mollusc Mytilus galloprovincialis under conditions of natural oxidative stress].

The state of the antioxidant (AO) system (AOS) and the content of products of lipid peroxidation (LPO) in hepatopancreas, gill, and foot of the Black Sea mollusc Mytilus galloprovincialis Lam. were studied in norm and under conditions of natural oxidative stress (spawning). It has been established that under conditions of spawning, the AO-protection of hepatopancreas cells is predominantly oriented to inactivation of high concentrations of peroxide compounds with participation of glutathione peroxidase and catalase. In the foot tissue, on the contrary, the main role in AO-processes is played by enzymatic inhibition of superoxide anionradical with aid of superoxide dismutase. The highest level of oxidative stress in the spawning state is revealed in the mollusc gill, which is indicated by the maximal increase of the content of TBK-active products.

[Antioxidant enzyme complex of tissues of the bivalve Mytilus galloprovincialis Lam. under normal and oxidative-stress conditions: a review].

The results of studies of tissue specifics of the enzymatic antioxidant complex of the bivalve Mytilus galloprovincialis Lam. are summarized. It is shown that the highest oxidative load is experienced by gills. The antioxidant complex of gills largely depends on environmental conditions than on the mollusk's state, which allows this tissue to be used for ecological diagnostics. A decrease in the content of carotenoids in tissue s suppressed the activities of the key enzymes of antiradical defense-superoxide dismutase (SOD) and catalase-and is accompanied by a decrease in the reduced glutathione (GSH) pool. The state of the antioxidant complex of molluscan tissues under conditions of natural (spawning) and artificial (exposure to a cationic surfactant) oxidative stress was studied.