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Microparasites of worldwide mullets

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The present review is focus on parasitic organisms, previously considered as protozoans. Viral, prokaryotic and fungal parasites caused diseases and disorders of worldwide mullets were also observed. Most of the known viruses associated with a high mortality of mullets were detected in Mugil cephalus. Prokaryotic microparasites were registered in M. cephalus, Moolgarda cunnesiu, Liza ramada and Mugil liza. Fungal pathogens were associated with representatives of the genera Aphanomyces, Achlya, Phialemonium, Ichthyophonus. Ichthyophonus sp. can be considered as a potential threat for marine fish aquaculture, especially in culture conditions. A new hyperparasitic microsporidium like organism was recorded in myxozoan Myxobolus parvus infecting grey mullet Liza haematocheilus in the Russian coastal zone of the Sea of Japan. The protozoan representatives of the phyla Dinoflagellata, Euglenozoa, Ciliophora and Apicomplexa were reviewed and analyzed. The review of myxosporean parasites from grey mullets includes 64 species belonging to 13 genera and 9 families infecting 16 fish species.
The microsporidium Nosema pontogammari Ovcharenko and Kurandina, 1987 was detected in the muscles of Pontogammarus robustoides collected in the stream of South Baltic Coastal Zone (sample site N 54°16', E 19°25') The parasite infects the cytoplasm of the muscle cells. The presence of remarkable intracytoplasmic vacuoles was noted inside of some parasite cells. Transmission electron microscopy showed that these intracytoplasmic vacuoles contained numerous microorganisms identified as rickettsialike prokaryotic cells. Groups of pleiomorphic in shape bacilliform and rounded cells were enveloped in electron-dense cover 20-30 nm wide. The prokaryotic cells wali was constructed out of triple layered coat of different electron density. The cytoplasm of infected cells was degenerated with weakly developed endoplasmic reticulum and undeveloped organelles. The obtained data demonstrate pathogenic nature of host-parasite relationship between endosymbiotic rickettsia-like organism and microsporidia.
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Meandry systematyki mikrosporydiow

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Meanders of systematics of Microsporidia. Taxonomical questions of Microsporidia, its systematic position and evolutionary relationship with other Eukaryota are discussed. Utilizations of modern methods of investigations of microsporidians cause new taxonomical troubles. At the present time it is difficult to create a clear hypothesis concerning the phylogeny and evolution of Microsporidia. Most likely they are representatives of a new kingdom of Eukaryota. Existing problems will not be dissolved until new detailed data concerning the new and common species are obtained.
212 freshwater fishes, belonging to 7 species, were examined for the presence of trypanosomes. The fishes were coming from breeding ponds in Gołysz (Silesia). The blood smears were fixed with methyl alcohol and stained with Giemsa method. Trypanosoma carassii MITROPHANOW, 1883 was found in blood of roach Rutilus rutilus (L.) (in 4 out of 19 examined specimens) and tench Tinca tinca (L.) (in 2 examined fishes). In trypanosomes from blood of both species of host there was observed a considerable variety of forms and size of body. Morphological description is completed with morphometrical values in the Tab. 2. Our own morphological description and morphometrical values have been compared with those of other authors. The authors of this paper agree with the opinion of LOM and DYKOVA (1992) that Trypanosoma tincae LAVERAN et MESNIL, 1904 is the synonym of Trypanosoma carassii.
Ultrastructural data of the sporulation stages of the microsporidium Gurleya orchestiae, infecting the muscles of talitrid amphipods Orchestia sp. (Crustacea, Amphipoda), are presented. The developmental stages of the parasite have isolated nuclei. Sporogonial reproduction is by rosette-like budding. Sporophorous vesicles contain 4, seldom 8 spores. The episporontal space contains granules and tubules. Spores are of oval shape, monokaryotic with lamellate bipartite polaroplast, double-layered exospore and isofilar polar filament, turned into 8-9 coils.
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