[THE SYSTEM OF XENOBIOTICS BIOTRANSFORMATION OF HELMINTHS. RESEMBLANCE AND DIFFERENSES FROM SIMILAR HOST SYSTEMS (REWEW)].

The three phases system xenobiotic biotransformation in cells as prokaryotes as eukaryotes was formed during the process of evolution. Clear and managed function of all three links of this system guarantee the survival of living organisms at alteration of chemical component of environment. Oxidation, reduction or hydrolysis of xenobiotics realize in phase I by insertion or opening reactive and hydrophilic groups in structure of drug molecule. In phase II xenobiotics or their metabolites from phase I conjugate with endogenic compounds, main of there are glutathione, glucuronic acid, amino acids and sulphates. Active transport of substrata, metabolites and conjugates through cell lipid membranes special transport proteins carry out (phase III). The system of xenobiotics biotransformation of helminths has essential differences from the same of vertebrate hosts. In particular, parasites do not reveal the activity of prime oxidases of phase I, such as CYP or FMO, in spite of the genes of these enzymes in DNA. As this phenomenon displays mainly in adult helminths, living in guts of vertebrates, then the hypothesis was formulated that this effect is related with adaptation to conditions of strong deficiency of oxygen, arise in a process of evolution (Kotze et al., 2006). Literature data testify the existence in helminths of unique forms of enzymes of phase II, the investigation of which present doubtless interest in relation with possible role in adaptation to parasitic mode of life. Notwithstanding that many of helminths GST in greater or lesser degree similar with enzymes of M, P, S and О classes of other organisms, nevertheless they have essential structural differences as compared with enzymes of hosts that makes perspective the search of specific anthelminthics vaccines. Transport of xenobiotics is now considered phase III of biotransformation. It was shown that proteins of this phase (ATP binding cassette transporters (ABC ) of parasites) play a key role in efflux of lipophilic xenobiotics, hydrophilic metabolites and conjugates and take part in forming of anthelminthics resistance. Some of these transporters, such as P-glycoprotein (Pgp), are important for drug resistance of helminths. In particular, a correlation between the level of expression of Pgp and resistance of S. mansoni and F. hepatica to widely used anthelminthics as praziquantel and triclabendazol exist.

[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.