Archive

It has been demonstrated that the critical date and critical photoperiod induced by the morphogenetic diapause of engorged larvae and nymphs of Ixodes persulcatus Schulze, 1930 showed both the latitude and longitude variability. Interspecies variation in ecological responses of larvae and nymphs to the day length were most pronounced in the latitudinal direction. Critical day length constituted 13.5—14.5 h in the southern part of I. persulcatus range (40—43° N) and up to 18—19 h in the northern part of the range (62° N). Longitudinal variation is closely linked to the climate, severity of which increases from West to East. For the first time it has been shown that mass induction of the diapause in nymphs may occur not only in the period of daylight length reduction, but also during the summer solstice, which occurs only in a sharply continental climate of Eastern Siberia. Adaptive advantages of such photoperiodic reaction for tick populations in short summer are discussed. The diapause in ticks occurs in response to environmental factors, such as changes in the photoperiod, and it is a major adaptation by which ticks synchronize their activity with biotic resources.

Features of reproductive structure of adult grouping of the hemipopulation (infrapopulation) of the Cosmocerca ornata (Dujardin, 1845) — the parasite of marsh frogs Pelophylax ridibundus (Pallas, 1771) were studied all-the-year-round including wintering of hosts. In wintering amphibians reproductive structure of the C. ornata hemipopulation is characterized by existence of maturing females and males of nematodes only. Infection of amphibians by nematodes did not occur. Growth, maturing and reproduction of parasites did not occur in wintering frogs. Dying off of part of nematodes was observed during this period. After wintering, during May and June, structure of adult grouping of the C. ornata hemipopulation was represented by last-year and new generations. Longevity of nematode females of spring and summer generations in marsh frogs constituted more than a month. The wintered females of C. ornata lived in amphibians for about 9 months. Authentic influence of water temperature on the process of appearance of the C. ornata in marsh frog population was revealed.

Статья суммирует данные по паразитам усатого гольца по всему ареалу его обитания, основанные на опубликованных данных. Список включает всех одноклеточных и многоклеточных паразитов усатого гольца из различных пресных водоемов (рек, озер, прудов, водохранилищ). В общей сложности у усатого гольца зарегистрировано 109 видов/таксонов паразитов (Kinetoplastidea — 4, Diplomonadea — 1, Coccidea — 2, Microsporea — 1, Myxosporea — 13, Litostomatea — 1, Phyllopharyngea — 2, Oligohymenophorea — 22, Monogenea — 10, Cestoda — 4, Trematoda — 31, Nematoda — 11, Acanthocephala — 5, Crustacea — 1, Bivalvia — 1). Самой многочисленной группой являются трематоды, 18 видов которых представлены метацеркариями.

The analysis of seasonal fish parasites infestation and the assemblage structure and its component communities structure was usually performed in May—October. Nevertheless, the winter season is important in the seasonal dynamics of parasite communities. The main aim of the reserach is to analyse the seasonal dynamics of structure of ruffe parasite community from the river Vychegda during the whole annual cycle. Three stable states of ruffe parasites community were revealed; they corresponded to various seasons: April, October, and January—early February. The first stable state was characterized by high values of diversity, number, and biomass of the parasites. The second one was characterized by the minimum diversity and average values of strength and biomass. The third one was characterized by the average diversity and the minimum strength and biomass of the parasites. In all the stationary states of community the minimum velocity of species structure transformation has been observed. Critical periods in development of the analyzed system corresponded to time of last year parasites dying off and infestation of the host by their new generations. It was shown that the seasonal dynamics of equation of fish parasite communities state and the tension of their mutual relations is adequately reflected by D^'_E index which estimates the difference of magnitudes of Shannon's indexes of domination, calculated from the number and biomass of participating species.

The Amur sleeper Perccottus glenii from the Ingoda River, the Shilka River, the Argun River, and Lake Dalai basins was examined for parasites. 17 species of parasites were reported. Description of metacercariae of Cryptocotyle sp., third-stage juvenile of Ichthyobronema hamulatum, and maritae of Echinochasmus japonicus raised in experiment are presented in the paper. Parasitological data showed that the Amur sleeper populations inhabiting the Shilka River, the Argun River, and Dalai Lake basins have descended from the ancestries which have spread from the lower parts of the Amur River basin (native part of Amur sleeper area). Another genesis was not excluded for the Amur sleeper population from the Ingoda basin, which may originate from specimens introduced from the Baikal region.

The liver fluke Opistorchis felineus (O. felineus) is the causative agent of opisthorchiasis; it causes serious health problems among human populations in the territory of Russia. Our research has focused on the development of diagnostic tools to detect infection caused by the parasite. A full-length sequence encoding 28 kDa glutathione-S-transfe-rase O. felineus was isolated from our cDNA library (Pomaznoy et al., 2013). The open reading frame contained 639 bp encoding 213 amino acids. We estimated potential of recombinant protein 28 kDa glutathione-S-transferase O. felineus (rOF28-GST) for application in immunodiagnosis of the opisthorchiasis. ELISA and western blot analysis showed that serum from patients infected with O. felineus could strongly react with purified rOF28-GST and healthy human sera could not. These results suggest the potential of this recombinant analogue of the 28 kDa glutathione S-transferase from O. felineus to develop the serodiagnostic test for human opisthorchiasis.

Parasites of the family Haemogregarinidae were detected in the Lake Baikal for the first time. They are marked in blood smears of the cottoid fish Leocottus kesslerii. Prevalence of infection was 14.9%.

---