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Morphological and molecular diversity of endobiotic and free-living trichomonads
Céza, Vít ; Čepička, Ivan (advisor) ; Bardůnek Valigurová, Andrea (referee) ; Fiala, Ivan (referee)
This PhD thesis presents the results of three subprojects focused on the research of so far understudied groups of the phylum Parabasalia. The previous research mostly focused on the parabasalids living in the guts of termites or on demonstrably pathogenic species. Surprisingly, there is only a little information about the impact of an increased contact of non-human primates with humans on the diversity of their intestinal trichomonads. Similarly, free-living trichomonads have been neglected for a long time, although they are likely crucial for understanding the evolution of Parabasalia as a whole. The diversity of the phylum Parabasalia is still poorly understood due to the brief and incomplete descriptions of many species, as well as a lot of missing sequence data. This doctoral project focused on the research of these hitherto understudied research areas. In the first subproject, a complete revision of the genus Hypotrichomonas was carried out, including the descriptions of six new species, some of which were found in previously well studied vertebrate hosts; these species must have been overlooked by the previous authors and the real diversity of intestinal trichomonads is certainly much higher than currently known. Because the most newly described species of Hypotrichomonas are readily...
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Cryptic diversity of free-living trichomonads and their phylogenetic position within Parabasalia
Céza, Vít ; Čepička, Ivan (advisor) ; Hampl, Vladimír (referee)
Trichomonads (Parabasalia) are anaerobic microeukaryotes classified in the supergroup Excavata. Inclusion of parabasalids within Excavata is exclusively based on the molecular- phylogenetic evidence. Over 400 species of parabasalids have been described so far, and the vast majority of them are endobiotic. In contrast, only few species of free-living parabasalids forming four independent lineages have been described (Pseudotrichomonas keilini, Ditrichomonas honigbergii, Monotrichomonas carabina, Honigbergiella sp., Tetratrichomonas undula, and Lacusteria cypriaca). Lacusteria cypriaca is a new species and genus described in our recent paper. In this paper we published the first two sequences of SSU rDNA from Pseudotrichomonas keilini as well. All of these lineages are likely secondarily free-living, and they developed from endobiotic ancestors. In addition to the already published Lacusteria cypriaca and Pseudotrichomonas keilini strains, we have recently obtained seven another isolates of free-living trichomonads (LAGOS2D, E2NT, CK, LAGOS2M, GR8, GOU23 LIVADIAN, and VAV1A1); from all of these isolates we sequenced SSU rDNA and performed phylogenetic analyses. These isolates split into four independent evolutionary lineages, which indicate that free-living parabasalids are more diversed and...
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