Search

The effect of short-term hypoxia (40 h) on the state of the antioxidant complex was studied in the Black Sea cockle Cerastoderma glaucum (Bruguiere, 1789) (Bivalvia: Cardiidae) with a high tolerance to oxidative stress. The activities of glutathione peroxidase (GP), glutathione reductase (GR), superoxide dismutase (SOD) and catalase, the level of TBA-reactive products and reduced glutathione (GSH) were studied in the hepatopancreas, gills, and foot of the mollusk. Tissue specificity of antioxidant complex reactions was revealed under hypoxia conditions. SOD activity dropped under hypoxia in all studied tissues. The greatest increase in TBA-reactive products and in the glutathione level was recorded in the gills. The GP and catalase activities increased significantly in the hepatopancreas and foot. In general, these reactions reflect a rather high adaptability of the mollusk to short-term hypoxia.

Bivalve molluscs are widespread in coastal environments, where they are subjected to a wide range of environmental fluctuations, which can represent a significant impact to their antioxidant status...

Aim. Study of a group of biochemical parameters of the hepatopancreas and gills of the Black Sea mussel Mytilus galloprovincialis Lam. and the functional indicator of cardiac system adaptivity of mussels from Sevastopol bays with different levels of recreational and anthropogenic impact.Methods. Mussels were collected from four Sevastopol water areas (Kruglaya Bay, Kazachya Bay, Matyushenko Bay and Cape Khrustalnii) in autumn 2018. The bioindication methods used were based on application of functional (cardiac system adaptability) and biochemical indicators (antioxidant enzymes activity [AEA], aminotransferases, the alkaline phosphatase [AP], and products of the lipid peroxidation [LPO] and protein oxidation [PO]) of mussel tissues. The hydrochemical parameters of the investigated areas were determined.Results. The anthropogenic impact on a complex of biochemical indicators of mussels at the sampling sites was shown. At the same time, low values of mussel heart rate (HR) recovery time (Trec) (less than 60 min.) in all sampling sites demonstrated the efficiency of biochemical changes in mussels and the possible use of all tested bays as recreational areas.Conclusion. Results of the present research allow the characterization of the ecological status of these Sevastopol sea water areas and to make recommendations about their rational use. Matyushenko and Kazachya Bays are most suitable for beach recreation and recreational fishery. Kazachya Bay also has favourable conditions for the development of water sports. Kruglaya Bay and Cape Khrustalnii are less ecologically safe and require a series of actions to improve water quality.

Studying the diversity of energy production pathways is important for understanding the evolutionary relationships between metabolic pathways and their biochemical precursors. The lactate/malate dehydrogenase (LDH/MDH) superfamily has been a model system for structural and functional evolution for a long time. Recently, the type-2 family of LDH/MDH (or LDH2/MDH2 oxidoreductase) has been identified. The LDH2/MDH2 oxidoreductase family is now known to have functionally more diverse enzymes than the LDH/MDH superfamily. In channel catfish, the gene encoding the LDH2/MDH2 oxidoreductase has been found (and was provisionally termed AqE). Homologs of this enzyme are predominantly present in organisms living in an aquatic environment. In this work, we studied the AqE gene distribution among non-tetrapod vertebrates. It was found that the AqE gene is present in the genomes of bony and cartilaginous fish and in the genomes of hagfishes and lampreys. In addition, it has been confirmed that in representatives of Cypriniformes, the AqE gene has been lost. AqE in representatives of Salmoniformes underwent significant deletions, which most likely led to its pseudogenization. In most orders of non-Tetrapoda vertebrates, the AqE gene remains highly conserved, suggesting that the AqE gene in aquatic vertebrates is an essential gene and undergoes rigorous selection. The AqE gene has the highest sequence similarity with the archaeal ComC gene that encodes sulfolactate dehydrogenase (SLDH). Based on the similarity of substrates, the enzyme encoded by the AqE gene is likely involved in the malate–aspartate shuttle mechanism or the biosynthesis of the energy coenzyme M equivalent.

The antioxidant glutathione system (AGS) and lipid peroxidation (LP) level in tissues of the Black Sea cockle Cerastoderma glaucum (Bruguiere, 1789) have been investigated and compared with those of other Black Sea bivalve mollusks with high resistance to oxidative stress (OS), namely, mussel Mytilus galloprovincialis (Lamarck, 1819) and anadara Anadara kagoshimensis (Tokunaga, 1906). The activity of glutathione peroxidase (GP) and glutathione reductase (GR) and the level of reduced glutathione (GSH) and LP products are measured in the hepatopancreas, gills, and foot of the mollusks. The parameters of AGS in C. glaucum are found to have tissue specificity. The hepatopancreas has the highest GP activity, 1.7–4.2 times higher than in the gills and foot of the mollusk. The gills have the lowest GSH level (by a factor of 2.1–2.3 times lower) and the highest GR activity (3.1–5.8 times higher) when compared to other tissues. In the cockle foot, the level of GSH is close to that in hepatopancreas and the activity of GP and GR is by a factor of 1.7–4.2 lower than in other tissues. In all studied tissues of C. glaucum, the LP level is significantly lower, i.e., by a factor of 3.2–16.3, when compared with that in mussel and anadara.

We studied the specific features of the joint activity of the enzyme and low-molecular weight parts of the antioxidant (AO) complex in the tissues of two species of the Black Sea bivalve mollusks with different resistance to oxidative stress: a native species, the Mediterranean mussel Mytilus galloprovincialis Lam., and an invader, the ark clam Anadara kagoshimensis (Tokunaga, 1906). In the hepatopancreas and the gills and foot of mollusks, the activity of glutathione peroxidase (GP), glutathione reductase (GR), superoxide dismutase (SOD), catalase, and the level of reduced glutathione (GSH), as well as the contents of glucose, amino acids, and products that react with thiobarbituric acid (TBA-reactive products), have been analyzed. The enzyme part had a leading role in AO defense in the tissues of the Mediterranean mussel. This is indicated by higher activities of GP (hepatopancreas, gills) and SOD (hepatopancreas, foot) but a smaller content of GSH (gills, foot) as compared with ark clam. In ark clam tissues, the role of low-molecular weight part is significant, which is confirmed by the higher GSH level (gills, foot) in combination with the higher activity of GP (foot) and SOD and catalase (gills) than that observed in the Mediterranean mussel. Unlike the mussel, ark clam tissues showed a more effective joint activity of SOD, catalase, and glutathione system, which resulted in a significantly lower content of LPO products than that found in all of the studied Mediterraneanmussel tissues. These features of the joint activity of the enzyme and low-molecular weight parts of the AO complex of the Mediterranean mussel and ark clam largely determine the difference in the resistance to oxidative stress in the mollusks of these species. The results confirm the prevailing idea of the ark clam as one of the most competitive invaders as compared with native species; it has successfully mastered new biotopes in the Azov-Black Sea basin and has become an important component of benthic communities.

The contents of amino acids and glucose, the activity of alanin aminotransferase (ALT), aspartate aminotransferase (AST), and the AO enzymes superoxide dismutase (SOD), catalase, glutathione peroxidase (GP), and glutathione reductase (GR), as well as the level of reduced glutathione (GSH) and TBA-reactive products, were investigated in the hepatopancreas, gills, and the foot of Black Sea bivalve mollusks: the blood cockle Anadara kagoshimensis (Tokunaga, 1906) (Bivalvia: Arcidae) and the mussel Mytilus galloprovincialis (Lamarck, 1819) (Bivalvia: Mytilidae) with their different tolerances to oxidative stress. Higher contents of glucose in the hepatopancreas and the foot and amino acids in the foot and a higher activity of AST in the gills were found in the mussel, which is relatively tolerant to hypoxia. Compared to blood cockle, mussels showed a higher GP and GR activity in hepatopancreas, GP activity in gills, and SOD activity in hepatopancreas and foot against the background of a higher content of TBA-reactive products in all studied tissues. A high content of amino acids was determined in the hepatopancreas and the gills of the blood cockle, which had a high tolerance to low oxygen. The activity of the ALT and AST enzymes in the foot and the activity of the ALT enzyme in the gills were higher in the blood cockle tissues than in the mussel tissues. This can be connected with more intensive processes of deamination and re-amination of amino acids in the cockle than in the mussel. The blood cockle had higher GP activity and GSH content in the foot and higher activity of SOD, catalase, and GR, as well the GSH level in the gills with a lower content of TBA products. The revealed peculiarities of the AO complex reflect adaptations of the mollusks to the oxygen regime in their habitat on the basis of specific peculiarities of their carbohydrate–protein metabolism.

Bivalve mollusks are frequently subjected to fluctuations of dissolved oxygen concentration in the environment which can represent a significant threat to bivalve antioxidant status. In this work the effects of hypoxia on hemocyte reactive oxygen species (ROS) production and level of mitochondrial potential as well as the activity and expression level of catalase (CAT) and superoxide dismutase (SOD) in gills of Crassostrea gigas were investigated after 24 h and 72 h exposure. 24 h hypoxia promoted an increase of mitochondrial membrane potential in agranulocytes and induced ROS accumulation in granulocytes. 72 h exposure substantially decreased hemocyte mitochondrial potential and intracellular ROS level in all hemocyte types. No significant changes in the activity of CAT in gills were observed following both 24 h and 72 h exposure periods compared to control. SOD activity in gills decreased after 72 h exposure to hypoxia but did not change under 24 h hypoxia. Significant up-regulation of SOD gene and no changes in expression level of CAT were observed in all experimental groups. The results indicate an overall shift in antioxidant status in gills and hemocytes of the Pacific oyster that may act as compensatory mechanisms to maintain redox homeostasis after a short-term (24 h) exposure and represent the occurrence of oxidative stress conditions at the end of 72 h hypoxia.

The morphology and immunological phenotype of plastic-adherent cells from human colostrum were studied in an in vitro short-term culture (6–7 days) using antibodies to CD3, CD31, CD34, CD45, CD68, vimentin, and osteocalcin. In 20% of the analyzed cultural flasks, nearly equal proportion of fibroblast-like cells and rounded cells was observed. In the 80% of the flasks, cells of regular shape were detected with the presence of single fibroblasts. The diameter of flattened cells ranged from 10 to 100 μm. All plastic-adherent cells did not express CD3 and showed weak binding (w) to the antibodies against CD31, CD34, and CD45. At the same time, we identified adherent cells that readily bound the antibodies against CD68, vimentin, and osteocalcin. According to the literature data, the CD68 + CD3–CD31wCD34wCD45w immunological phenotype of the majority of the adherent cells from the colostrum allows them to be classified as monocytes/macrophages. High expression of stromal antigens—vimentin and osteocalcin—in 40–45% of the adherent cells in the culturing medium lacking any osteogenic supplements (β-glycerophosphate, ascorbic acid, and dexamethason) implies the presence of osteoblasts in the colostrum, which differentiate from mesenchymal stem cells under the action of humoral factors contained in breast milk.

Parameters of the antioxidant system as well as carbohydrate, protein, and energy metabolisms in the tissues of an invader species, the bivalve mollusk Anadara kagoshimensis, are compared. Tissue specificity of the examined parameters is demonstrated. Along with the hepatopancreas and gills, the foot of anadara is shown to be an important metabolic organ with a high metabolism and an antioxidant defense. The content of low molecular weight biological antioxidants and antioxidant enzyme activities are specifically balanced in the examined mollusk tissues. The behavioral, physiological, and biochemical features that have provided successful invasion of this mollusk in the Black Sea–Azov basin are discussed.

Combined effect of two stress factors (decreasing of salinity and presence of potassium dichromate in the medium) on adaptive capacity of benthic alga Attheya ussurensis is investigated. The salinity decreasing to 20 ‰ combined with 0.01 mg/L of K 2 Cr 2 O 7 in the medium didn’t cause any change of the cells growth in number, as compared with uncontaminated environment (32 ‰, control), or changes in their morphology. The same salinity decreasing with K 2 Cr 2 O 7 concentration 0.10 mg/L caused a lowering of the cells growth to 86 % of the control value by the end of experiment that was accompanied by minor morphological abnormalities, as cells elongation in pervalvar axis direction and granulation of chloroplasts. In the second seeding, there was no change of the cells growth again under the low concentration of K 2 Cr 2 O 7 and their adaptation to the concentration 0.10 mg/L was observed: in the end of experiment the cells number had no significant difference from the control one. The salinity decreasing to 16 ‰ with the toxicant concentration 0.01 mg/L caused a lowering of the cells growth in the 4 th day that persisted until the end of experiment and some insignificant changes of their morphology. The same salinity decreasing with the toxicant concentration 0.10 mg/L caused a significant drop of the cells number with strong negative morphological changes; moreover, the alga wasn’t able to adapt to this combined stress after re-seeding.

The level of reduced glutathione (GSH) and activity of glutathione-coupled antioxidative enzymes, glutathione peroxidase and glutathione reductase, as well as the level of glucose, carbamide and amino acids were studied in the hepatopancreas, gills and foot of the Black Sea mollusk Anadara kagoshimensis. A highest level of GSH and highest activity of glutathione peroxidase were detected in the foot indicative of an active antioxidative role glutathione plays both within the enzyme and independently. The levels of glucose, amino acids and carbamide were highest in the hepatopancreas and gills and lowest in the foot. A possible involvement and role of these low molecular weight antioxidants in the defense of mollusk tissues from free radical oxidation and in the adaptation to hypoxic habitat is considered.

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.

Using high performance liquid chromatography, UV-VIS spectra and mass-spectra (FAB MS), 7 carotenoid species were identified in tissues of the bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789): trans- and cis-pectenolon, alloxanthin, pectenol A, β-carotene, zeaxanthin, and diatoxanthin. Their quantitative ratio in hepatopancreas, gills and foot of animals were determined. A negative correlation (R 2 is about 0.9) was revealed between tissues content of a series of carotenoids (trans- and cis-pectenolon, zeaxanthin, alloxanthin, and diatoxanthin) and activity of antioxidant enzymes (catalase and superoxide dismutase). The existence of competitive interrelations between these molecular systems is proposed and underlying causes are discussed.

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.

The peculiarities in distribution of lipid peroxidation (LPO) products, glutathione (GSH) level, and antioxidant enzymes-glutathione peroxidase (GP) and glutathione reductase (GR)—were studied in tissues of Black Sea bivalve molluscs, Anadata inaequivalvis Br. (anadara) and Mytilus galloprovincialis Lam. (mussel, black morph), as well as their comparative characteristics were presented. The differences were established in organization of the glutathione anti-oxidant system and the LPO intensity in tissues of these mollusc species. In all anadara tissues the intensity of LPO processes was lower than that in Mytilus galloprovincialis. The GP activity in hepatopancreas and gills of mussels was significantly higher than that of anadara. On the contrary, in the foot the GP activity and GSH content in anadara considerably exceeded those in mussel. The revealed differences might reflect the peculiarities in functioning of the glutathione complex and the ratio of its activity with LPO level in tissues of anadara and mussel, as well as be of interest for understanding mechanisms of mollusc adaptation to their habitat conditions.

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 anion radical 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 TBA (thiobarbituric acid)-active products.

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.