HEMATOLOGICAL PARAMETERS AND PARASITE FAUNA OF AMUR SLEEPER PERCCOTTUS GLENII IN A SINGLE-SPECIES ICHTHYOCENOSIS OF A SMALL URBAN RESVOIR

The article presents the results of hematological and parasitological studies of Amur sleeper Perccottus glenii of a small reservoir of artificial origin located in the vicinity of Perm. In this reservoir, Amur sleep-er is the only representative of the ichthyofauna. The collection of material was carried out in the spring-summer period of 2019. A total of 55 specimens of Amur sleeper were studied (30 specimens on May 8 and 25 specimens on July 12). Significant differences were found in the majority of quantitative indicators of fish blood cells in the spring and summer periods: in summer, the number of hematopoietic cells is higher (except for lymphocytes and monocytes), and in general, the content of mature leukocytes in the blood microliter in summer is lower. The parasite fauna of Amur sleeper in the studied reservoir is ex-tremely impoverished and is represented by the infusoria Trichodina nigra, cestode Nippotaenia mogurndae and nematodes, the latter were not recorded in Amur sleeper in this reservoir previously. The relationship between hematological parameters and the extent of parasite invasion was revealed: in more infected fish the number of immature erythrocytes, protoleukocytes, as well as neutrophils and eosinophils is significantly higher. The large numbers of Amur sleeper in the studied reservoir, the absence of devel-opmental anomalies in all the studied specimens, and the low proportion of fish with blood cell patholo-gies indicate the relative well-being of the studied part of the Amur sleeper population.

Parasitic infections of two invasive fish species, the Caucasian dwarf goby and the Amur sleeper, in Hungary

In recent years and decades, two new fish species, the Caucasian dwarf goby (Knipowitschia caucasica) and the Amur sleeper (Perccottus glenii) have become members of the Hungarian fish fauna. In a 14-month study on the parasite fauna of these species, the authors detected 11 parasite species in the Caucasian dwarf goby and 17 species in the Amur sleeper. All parasites found in dwarf goby belong to species commonly occurring also in native Hungarian fishes, but three species (Goussia obstinata, Gyrodactylus perccotti and Nippotaenia mogurndae) collected from the Amur sleeper are introduced species new for the Hungarian fauna.

Telomere analysis of platyhelminths and acanthocephalans by FISH and Southern hybridization

We examined the composition of telomeres in chromosomes of parasitic worms, representatives of the flatworm groups Monogenea and Cestoda (Platyhelminthes), and thorny-headed worms (Syndermata: Acanthocephala) by fluorescence in situ hybridization (FISH) with different telomeric repeat probes. Our results show that the (TTAGGG)n sequence, supposed to be the ancestral telomeric repeat motif of Metazoa, is conserved in Monogenea ( Paradiplozoon homoion ) and Cestoda ( Caryophyllaeus laticeps , Caryophyllaeides fennica , and Nippotaenia mogurndae ) but not in Acanthocephala ( Pomphorhynchus laevis and Pomphorhynchus tereticollis ). In the Pomphorhynchus species, no hybridization signals were obtained with the “nematode” (TTAGGC)n, “arthropod” (TTAGG)n, and bdelloid (TGTGGG)n telomeric probes using FISH with their chromosomes and Southern hybridization with P. laevis DNA. Therefore, we suggest that parasitic Acanthocephala have evolved yet unknown telomeric repeat motifs or different mechanisms of telomere maintenance.