Jiri Vavra

Molecular phylogeny and evolution of mosquito parasitic microsporidia (Microsporidia: Amblyosporidae)

Abstract Amblyospora species and other aquatic Microsporidia were isolated from mosquitoes, black flies, and copepods and the small subunit ribosomal RNA gene was sequenced. Comparative phylogenetic analysis showed a correspondence between the mosquito host genera and their Amblyospora parasite species. There is a clade of Amblyospora species that infect the Culex host group and a clade of Amblyospora that infect the Aedes/Ochlerotatus group of mosquitoes. Parathelohania species, which infect Anopheles mosquitoes, may be the sister group to the Amblyospora in the same way that the Anopheles mosquitoes are thought to be the sister group to the Culex and Aedes mosquitoes. In addition, by sequence analysis of small subunit rDNA from spores, we identified the alternate copepod host for four species of Amblyospora. Amblyospora species are specific for their primary (mosquito) host and each of these mosquito species serves as host for only one Amblyospora species. On the other hand, a single species of copepod can serve as an intermediate host to several Amblyospora species and some Amblyospora species may be found in more than one copepod host. Intrapredatorus barri, a species within a monotypic genus with Amblyospora-like characteristics, falls well within the Amblyospora clade. The genera Edhazardia and Culicospora, which do not have functional meiospores and do not require an intermediate host, but which do have a lanceolate spore type which is ultrastructurally very similar to the Amblyospora spore type found in the copepod, cluster among the Amblyospora species. In the future, the genus Amblyospora may be redefined to include species without obligate intermediate hosts. Hazardia, Berwaldia, Larssonia, Trichotuzetia, and Gurleya are members of a sister group to the Amblyospora clades infecting mosquitoes, and may be representatives of a large group of aquatic parasites.

Vairimorpha disparis n. comb. (Microsporidia: Burenellidae): a redescription and taxonomic revision of Thelohania disparis Timofejeva 1956, a microsporidian parasite of the gypsy moth Lymantria dispar (L.) (Lepidoptera: Lymantriidae).

ABSTRACT. Investigation of pathogens of populations of the gypsy moth, Lymantria dispar (L.) in Central and Eastern Europe revealed the existence of a microsporidium (Fungi: Microsporidia) of the genus Vairimorpha. The parasite produced three spore morphotypes. Internally infective spores are formed in the gut and adjacent muscle and connective tissue; single diplokaryotic spores and monokaryotic spores grouped by eight in sporophorous vesicles develop in the fat body tissues. The small subunit rDNA gene sequences of various isolates of the Vairimorpha microsporidia, obtained from L. dispar in various habitats in the investigated region, revealed their mutual identity. In phylogenetic analyses, the organism clustered with other L. dispar microsporidia that form only diplokaryotic spores in the sporogony cycle. The octospores of certain microsporidia infecting Lepidoptera that were previously described as Thelohania spp., have recently been shown to be one of the several spore morphotypes produced by species in the genus Vairimorpha. Because the description and drawings of a parasite described as Thelohania disparis by Timofejeva fit the characteristics of Vairimorpha, and all octospore‐producing microsporidia collected from L. dispar since 1985 are genetically identical Vairimorpha species, it is believed that the parasite characterized here is identical to T. disparis Timofejeva 1956, and is herein redescribed, characterized, and transferred to the genus Vairimorpha as the new combination Vairimorpha disparis n. comb.

Molecular Phylogenetic Relatedness of Frenkelia spp. (Protozoa, Apicomplexa) to Sarcocystis falcatula Stiles 1893: Is the Genus Sarcocystis Paraphyletic?

ABSTRACT The coccidians Frenkelia microti and F. glareoli (Apicomplexa: Sarcocystidae) form tissue cysts in the brain of small rodents (intermediate hosts) while oocysts are formed in the intestine of final hosts, buzzards of the genus Buteo. The inclusion of the small subunit ribosomal RNA gene sequences (SSU rRNA) of both Frenkelia species into the SSU rRNA trees of other, tissue cyst‐forming coccidia strongly supports paraphyly of the genus Sarcocystis. Frenkelia spp. exhibit close relatedness to Sarcocystis falcatula Stiles 1893, a bird‐opossum parasite, recognized under its junior synonym S. neurona Dubey et al. 1991, as the causative agent of equine protozoan myeloencephalitis on the American continent. As the definition of the genus Frenkelia is based on a plesiomorphic character (affinity to the neural tissue) of supposedly low phylogenetic value, the synonymization of the genus Frenkelia with Sarcocystis is proposed. This renders the genus Sarcocystis monophyletic.

Ultrastructural study and description of Ordospora colligata gen. et sp. nov. (microspora, ordosporidae fam. nov.), a new microsporidian parasite of Daphnia magna (Crustacea, Cladocera)

Summary The new microsporidium Ordospora colligata gen. et sp. n. is described with emphasis on the ultrastructural characteristics. The parasite, which is superficially similar to Glugoides intestinalis (Chatton, 1907), invades the gut epithelium of Daphnia magna, where the complete development takes place in a host cell-derived parasitophorous vacuole. Merogonial and sporogonial stages occur together in the vacuole, with presporal stages at the periphery, mature spores aggregated in the centre. All life cycle stages have isolated nuclei. Merogonial plasmodia are initially rounded, later elongated, and they give rise to four merozoites. The bouts of merogony are unknown. The sporont produces two sporoblast mother cells, which often remain coupled. Each cell generates a chain of four sporoblasts. Sporophorous vesicles are not produced. Mature spores are pyriform with a pointed anterior pole and with an obliquely positioned posterior vacuole. Unfixed spores measure 1.33–2.29 × 2.32–3.69 urn. The exospore is uniform, about 11 nm thick. The polar filament is isofilar, 82–85 nm wide, making 5–6 coils in the posterior half of the spore. The polaroplast is uniform, composed of about 28 nm, wide lamellar components, where the lamellae are folded around each other. The discrimination from other microsporidian species and the systematic position are briefly discussed. A new family, Ordosporidae, is established and Endoreticulatus durforti Martinez et al., 1993 is transferred to Ordospora.