Архив выпусков

The study of the composition of proteins (proteome) of helminths is necessary for revealing of molecular basis of life of a parasitic organisms and clarifying of biochemical mechanisms underlying «parasite-host» relationships. It is useful for determination of potential targets for the chemotherapy and drug design. The review demonstrates the insights in the proteomic research of helminthes. The major groups of proteins were described, such as structural proteins, carbohydrate metabolism enzymes and proteins of stress response. Comparative studies of proteins at various stages of the life cycle of helminthes reveal proteins with different expression level at larval and sexually mature individuals. Particular attention is drawn for secretory proteins of parasites, called secretome. Proteins of secretome (various proteolytic enzymes, proteins of the detoxification system, etc.) play an important role in parasite's defense against host immunity, feeding and penetration through the host tissue barriers.

An adults and nestlings of herring gulls Larus argentatus were investigated. The indicators of infestation by the trematode Gymnophallus deliciosus (Trematoda: Gymnophalli-idae) were determined. The biochemical parameters in plasma and liver of gulls were measured. The concentration of total protein, albumin, total lipids, triacylglycerols, phospholipids, cholesterol, urea and bilirubin, and the activity of alanine aminotransferase and aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, amylase and cholinesterase were examined in the blood plasma of the infected and uninfected birds. The intensity of lipid peroxidation, the content of total carotenoids and vitamin A were determined in the liver of the infected and uninfected birds. The intensity of infestation of G. deliciosus of the nestlings made 2—78 ind. (19.0 ± ± 5.4 ind.) and the adult gulls from 1 to 53 ind. (17.1 ± 2.5 ind.). The birds that infected by G. deliciosus had the enlarged gall bladder irrespective of age. Analysis of biochemical parameters showed that the invasion of G. deliciosus in the organism of adult herring gulls and nestlings changed in the functioning of the gall bladder and bile ducts (increase of concentration of total bilirubin and activity of amylase and alkaline phosphatase in blood plasma) and disrupted in lipid metabolism (decrease of concentration of total lipids and triacylglycerols). A proteolytic function of the liver cells in adults' gulls, the infected gymnophallidae, reduced (decrease in the content of total protein and albumin). It is established that the invasion of G. deliciosus in the gallbladder herring gulls does not lead to severe disorders of liver function.

For the first time, a parasitological study was conducted of ninespine stickleback Pungitius pungitius, inhabiting the downstreams of the Penzhina River. Eleven species of parasites were found, including five that are specific to these fish: Eimeria gasterostei, Myxobilatus gasterostei, Trichodina tenuidens, Diplostomum pungitii, and Neoechinorhynchus beringianus. In addition to euryhaline and marine species (36.4%), seven freshwater parasites (63.6%) have been registered. Among the parasites myxosporeans were predominating, while monogeneans and cestodes, and also freshwater infusorians were not present. The basis of the diet of ninespine sticklebacks in July is the larvae of chironomids (85%) and imago of diptera (35%), rarely planktonic crustaceans, nematods, diatoms, osracods and larvae of ephemeropterids.

Alimentary activity and mortality of fleas non-infected with Yersinia pestis and ectoparasites with initial contamination level 50 and 100 % at feeding on non-specific host (white mouse) were examined. It was determined that presence of the plague agent in fleas significantly stimulated the activity of its feeding, especially in females. The effect of contamination to fleas' mortality was not found. At the same time, males died more frequently in comparison with females. Complete and partial blocks in ectoparasite groups with different initial infection rate were mainly observed in females; no quantitative differences were revealed. The total part of fleas with Y. pestis biofilms (blocks and «aggregations») per one blood meal depended significantly on the initial infection rate. Some females maintained the plague agent in aggregated form after the third blood meal to the end of the experiment. In flea males the biofilm formation was a dynamic process consisted of the formation, destruction and elution, and also death of the individuals with bacteria.

A comparative analysis of molecular based phylogenies of Platyhelminthes and morphological data is provided. Some widespread mistakes in literature (the confusion of Cercomeromorpha hypothesis by Bychowsky and Cercomorpha hypothesis by Janicki, the inclusion of turbellarians PNUK into the family Genostomatidae, etc) are revealed. Synapomorphies for Neodermata proposed by different authors are critically assessed. The ultrastructure of flame bulbs in Neodermata is shown to be a plesiomorphic character rather than a synapomorphy. The morphological analysis proves that Neodermata evolved from the turbellarians close to the early Neoophora. Only the following synapomorphies of Neodermata do not give rise to doubt: 1) the neodermis; 2) the appearance of ciliated larvae; 3) the collar receptors with dense collar inserted into the membrane at the apical level. Other features may be synapomorphies as well as plesiomorphies as well as homoplasies.

Summary is absent.