Accumulation, functional and antioxidant responses to acute exposure to Di(2-ethylhexyl)phthalate (DEHP) in Mytilus galloprovincialis.

Mussels were exposed to di-(2-ethylhexyl) phthalate (DEHP) (0.4 mg L-1 and 4.0 mg L-1) for 24 h and 48 h and its effect on hemocyte cellular composition and spontaneous reactive oxygen production (ROS) levels in hemocytes were evaluated. Exposure to DEHP induced a loss in spontaneous ROS production levels in hemocytes and decreased agranulocyte number in hemolymph. DEHP was found to accumulate in hepatopancreas of mussels and this process was associated with an increase of catalase (CAT) activity after 24 h incubation. At the end of the experimental period (48 h) CAT activity recovered up to control levels. Superoxide dismutase (SOD) activity in hepatopancreas increased following 48 h exposure to DEHP. The results indicated that DEHP could affect hemocyte immune properties, and also cause non-specific general stress-response of the antioxidant complex, which, in turn, was not associated with pronounced oxidative stress.

Functional changes in hemocytes and antioxidant activity in gills of the ark clam Anadara kagoshimensis (Bivalvia: Arcidae) induced by salinity fluctuations.

This study describes the analysis of antioxidant enzymatic activities (catalase and superoxide dismutase) in gills and functional state of hemocytes (osmotic stability, mitochondrial membrane potential) of ark clams (Anadara kagoshimensis) from the Black Sea basin exposed to salinity stress. For this, the effects of 48 h periods of exposure to low (8 ‰, 14 ‰) and high (35 ‰, 45 ‰) salinity were assessed. Our results showed that ark clams, A. kagoshimensis, possessed pronounced tolerance to hypersalinity stress and are sensitive to a short-time hyposalinity treatment. Salinity 35 ‰ inhibited production of reactive oxygen species (ROS) by hemocytes and did not affect their levels of mitochondrial membrane potential. Acclimation to 45 ‰ salinity caused significant increase in mitochondrial membrane potential accompanied with recovery of intracellular ROS levels up to controls levels. Acclimation to low salinity (8 ‰) induced an increase in both ROS and mitochondrial membrane potential levels in hemocytes. Catalase and superoxide dismutase activity in gills decreased following acclimation to low (8 ‰) and high (35 ‰) salinity. Exposure to the highest salinity levels (45 ‰) led to a decrease of superoxide dismutase activity levels, but did not influence the levels of catalase activity. Acclimation to low and high salinity was not accompanied with changes in osmotic fragility of hemocytes despite osmotic fragility curve according to changes in hemolymph osmolarity. Based upon these results, we postulate the involvement of cellular osmoregulatory mechanisms in the adaptation of the ark clam to short-term fluctuations of environmental salinity.

Erythrocyte profile of circulating blood of Neogobius melanostomus (Pallas, 1814) under conditions of experimental hypothermia.

The influence of hypothermia on erythrocyte profile of thermophile teleost species round goby, Neogobius melanostomus (Pallas, 1814), has been studied. Fish were acclimated to temperature 1-2оС, 15-16оС and 19-20оС (control group) and held at given conditions for 5 days. The number of red blood cell precursors (pronormoblasts, basophilic and polychromatophilic normoblasts) in circulating blood has been estimated. Also, the number of abnormal erythrocytes, i.e. cells with micronuclei, nuclei invaginations, red blood cell shades, dacryocytes and cells undergoing amitosis has been determined on smears. The number of immature erythrocytes increased more than two times (p < 0,001) at 1-2оС. The number of low-differentiated precursors, pronormoblasts and early basophilic normoblasts, increased for the most part. The number of abnormal erythrocytes did not change substantially, The changes in cellular blood composition were accompanied with the increase of plasma lactate concentration, indicating hypoxic state of fish. The results of the present work indicate that hematopoietic tissue remains sensitive to controlling factors at hypothermia, such as hypoxia, and may enhance proliferation and differentiation of erythroid cells.

Morphologic, cytometric and functional characterisation of Anadara kagoshimensis hemocytes.

Circulating hemocytes of ark clam, Anadara kagoshimensis, were investigated using light microscopy and flow cytometry. Hemolymph contained 3 morphotype of cells, amebocytes, erythrocytes and intermediate type cells, which formed two distinct subpopulations on flow cytometric dot plots. Large cells (intermediate morphotype and erythrocytes) amounted 85.6 ± 2.8% total cells in hemolymph. Erythrocytes were hemoglobin-containing cells with up to 40 granules presented in the cytoplasm. All hemocyte types, observed in the ark clam hemolymph demonstrated equal capacity to spontaneous production of reactive oxygen species.

[FUNCTIONAL STATE OF SCORPION FISH SCORPAENA PORCUS L. NUCLEATED ERYTHROCYTES UNDER DOSED HYPOXIA].

Hypoxia is a wide spread phenomena throughout the world's aquatic systems. This paper investigates the functional state of scorpion fish red blood cells under acute hypoxia between 0.57-8.17 mg O2/l (in vitro) by assessing of the fluorescence of Rhodamine 123 (R123) and Fluorescein diacetate (FDA). Acute hypoxia induced a significant increase in the fluorescence of both fluorochromes (R123 - 12-60, FDA - 30-184%). This reaction is based on a probable decrease in erythrocyte membrane permeability. The reduction of functional ionic channels in red blood cells delays FDA in the cytoplasm and lowers the energy costs required for transmembrane cationic gradient maintenance, which reflects an intensification of R123 fluorescence.