Biologiya Morya

Dinoflagellates are a large group of protists with diverse morphogenetic forms and nutrition modes (phototrophy, mixotrophy, and heterotrophy). Outbreaks of dinoflagellate growth, known as harmful algal blooms (HABs), can cause deaths of fish, birds, mammals, and other animals, and pose a significant danger to human health due to the consumption of seafood contaminated with phycotoxins. Therefore, identifying the factors that influence the synthesis of phycotoxins is important for predicting possible HAB events. Increased synthesis of phycotoxins by dinoflagellates under laboratory conditions is necessary for their use in biotechnological applications. This review summarizes the literature data on the main physicochemical and biotic factors influencing the synthesis of toxins by marine photosynthetic dinoflagellates, particularly saxitoxin and its derivatives. The primary focus is on the abiotic factors such as concentrations of nitrogen, phosphorus, micronutrients, temperature, illumination, salinity, pH, and carbon dioxide. Several biotic factors are also considered. A significant effect of copepodamides, which are low-molecular-weight compounds synthesized by copepods, on the phycotoxin synthesis is noted. The genetic basis for phycotoxin synthesis is discussed using saxitoxin as an example.

The effect of erythrocyte sizes and protein-lipid, phospholipid, and fatty acid compositions of plasma membranes on the activity of the membrane ecto-ATPase was studied in two cartilaginous (Raja clavata, Dasyatis pastinaca) and eight teleost species (Scorpaena porcus, Uranoscopus scaber, Symphodus tinca, Diplodus annularis, Neogobius melanostomus, Spicara flexuosum, Trachurus mediterraneus, Gaidropsarus mediterraneus) of Black Sea fishes. The relationships between the high ecto-ATPase activity and the erythrocyte sizes were shown for both cartilaginous and teleost fish species. A higher relative protein content was found in membranes of the Black Sea rays, which probably indicates an evolutionary trend of decreasing proportion of the protein component and increasing lipids in teleost fishes. It was determined that fish erythrocytes with high protein content in the membrane have higher ecto-enzymatic activity. Plasma membrane phospholipids of fish erythrocytes are represented by five families: phosphatidylcholine (PC), phosphatidylethanolamine (PEA), phosphatidylserine, monophosphoinositide, and sphingomyelin. The high content of phospholipids and, in particular, PC and PEA in plasma membranes of fish erythrocytes is the basis for the formation of their bilayer matrix. Plasma membranes with a higher content of saturated fatty acids exhibited a higher ecto-ATPase activity, which indicated an important role of the enzyme in the physiology of the cell membrane and the blood flow in general.

The blood cells of common (harbor) seals, Phoca vitulina L. 1758, from the Commander Islands population are characterized in detail for the first time. Data on composition, size and ratio of erythrocytes, leukocytes, and platelets in the peripheral blood of immature and mature seals are given. A micrograph library for all types of peripheral blood cells of harbor seal is presented. The blood cells morphology of this seal generally corresponds to that of other pinniped species; however, neutrophils with Dohle bodies, reactive lymphocytes, and hypersegmented neutrophils were found in blood smears. An increased number of eosinophils (10–25%) were observed in the leukocyte formula of all seals examined. Mature seals had higher numbers of eosinophils (p = 0.04) and large lymphocytes (p = 0.005); immature seals had higher numbers of monocytes (p = 0.04) and Howell–Jolly bodies in erythrocytes (p = 0.03). Microfilariae and nucleated erythrocytes were found in blood smears of two mature seals.

The pea crab Pinnaxodes mutuensis Sakai 1939 was first found in the burrowing bivalve mollusk Panomya nipponica Nomura et Hatai, 1935 in Vladimir Bay near the Sea of Japan continental coast. Symbiotic relationships of this crab with the infaunal mollusks Ruditapes philippinarum (A. Adams et Reeve, 1850), Barnea manilensis (R. A. Philippi, 1847), and Mya japonica J. C. Jay, 1857 from Aniva Bay (southern Sakhalin), as well as with Panomya ampla Dall, 1898 from the coastal waters of Hokkaido, were previously known. Data on the ecology of P. mutuensis are summarized. The role of infaunal mollusks in its symbiotic life style is asumed to be more significant.