Fatty Acids Distribution in Seston, Tissues, and Faecal Pellets of Blue Mussels Mytilus edulis L.

The n-3 polyenoic fatty acids (phytoplankton origin) dominate in the fatty acid composition of seston, which is a food source for bivalves; this indicates the predominance of diatoms in the seston composition. The distribution of the main classes of lipids and their fatty acids in the tissues of blue mussels depends on the mollusk body size. As the body size of the mollusk increases, the ratio of membrane lipids decreases, and high-energy saturated and monounsaturated fatty acids accumulate in storage lipids. The bulk of the n-3 polyenoic acids consumed by mollusks in seston (i.e., their food) accumulates in the tissues of mollusks and is used for their metabolism, whereas the long-chain saturated fatty acids, oleic acid and the n-6 polyenoic acids, are excreted with faecal pellets.

[BIOCHEMICAL RESPONSE OF BLUE MUSSELS MYTILUS EDULIS L. FROM THE WHITE SEA TO RAPID TEMPERATURE CHANGES].

The effect of a rapid temperature change on the biochemical status of blue mussels Mytilus edulis L. from the White Sea was studied under conditions of aquarium experiment. It is shown that modifications of the composition of reserve and structural lipids and their fatty acids, of the activity of lysosomal enzymes (ß-glucosidases, cathepsins B and D), of calcium-dependent proteases of cytocol (calpains) and of the enzyme of the second phase of biotransformation of xenobiotics - glutathione-S-transferase, reflect an unspecific compensatory reaction of bivalves to stress action of environmental factors and indicate reconstruction of blue mussel metabolism as early as within first hours of temperature change. The initial high level of glutathione-S-transferase activity in control blue mussels as well as an increase of glutathione concentration in the course of experiment may facilitate successful exit of mussels from the state of reduced metabolism.

Effect of seawater desalination and oil pollution on the lipid composition of blue mussels Mytilus edulis L. from the White Sea.

A study on the effect oil pollution under normal and reduced salinity had on blue mussels Mytilus edulis L. from the White Sea in an aquarium-based experiment and in the natural habitat revealed a change in gill total lipids as a compensatory response. The cholesterol concentration and the cholesterol/phospholipids ratio in gills were found to reflect the impact of the environmental factors (oil pollution and desalination), and evidence adaptive changes in the cell membrane structure. An elevated content of storage lipids (chiefly triacylglycerols) in the mussels in the aquarium experiment indicates, first of all, the uptake and accumulation of oil products in gill cells under both normal and reduced seawater salinity, while high triacylglycerols level in gill littoral mussels from 'control' biotope in the Gulf of Kandalaksha is primarily associated with the mussel׳s pre-spawning period.

[Correlation of intracellular Ca(2+)-dependent proteinase activity and the content of membrane lipid components in mussel, Mytilus edulis, under heavy metal accumulation].

Correlation of calpain activity level and some membrane lipid component contents in organs of mussels, Mytilus edulis L., was shown in aquarial experiment on the study of mussel response reactions on the exposure of different levels of copper and cadmium. The correlation observed possibly could be explained by the effector role of membrane lipid components (arachidonic acid, phosphatidylinositol) on Ca(2+)-channels. Thus, the correlation between tissue lipid composition and protein functional activity was demonstrated with intracellular Ca2+ level as a key member.

[Modulatory role of lipids and their fatty acids in adaptation of the White Sea mussels Mytilus edulis L. to environmental salinity changes].

Role of lipids and fatty acids (FA) in littorial and sublittorial White Sea mussels Mytilus edulis L. was studied at various stages of reproductive in the phenotypic adaptation (acclimation) to changes of the sea water salinity. The obtained data indicate differences in the mussel lipid and fatty acid spectra, which are connected both with their location (littoral and sublittoral) and with the spawning period stage (3b--release of gametes and 3c--resorption of residual sex products). Lipids and FA of both mussel groups respond to the salinity changes to the greater degree at the 3b than at the 3c stage. In the littorial mussels at the stages 3b and 3c there were revealed differently directed changes in the content of membrane lipid--cholesterol--and in the cholesterol : phospholipids ratio. In the sublittorial mussels that are less adapted to extreme action of abiotic factors, more significant changes were found in the lipid and FA compositions.