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Diversity of anaerobic ciliates
Nováková, Ludmila ; Čepička, Ivan (advisor) ; Kostka, Martin (referee)
Ciliates (Ciliata) are single-celled eukaryotic organisms belonging to the large group Alveolata. Ciliates are classified to eleven classes. Anaerobic/microaerophilic representatives belong to classes Armophorea, Litostomatea, Plagiopylea, Oligohymenophorea, and Prostomatea. The mitochondrion of the anaerobic ciliates has been tranformed to hydrogenosome. The anaerobic ciliates are characteristic for the presence of methanogenic symbionts in the cytoplasm near hydrogenosomes. Anaerobic flagellates are free-living or they live as commensals, mutualists or parasites in the digestive tract of animals including humans. The true diversity of anaerobic ciliates is still not fully understood. The reason is that only sequences of described ciliate species are usually included into phylogenetic analyses. However, many environmental sequences representing considerable part of known molecular diversity of ciliates have been published as well. The aim of this work was to obtain and analyze sequence data of anaerobic free-living ciliates. We have determined SSU rDNA sequences of 32 different freshwater and marine strains of ciliates. Phylogenetic analyses showed that the strains belonged mostly to the classes Armophorea, Plagiopylea and Oligohymenophorea. The strain LIVADIAN belonged, together with genera...
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Diversity and phylogeny of Archamoebae
Zadrobílková, Eliška ; Čepička, Ivan (advisor) ; Kostka, Martin (referee) ; Bardůnek Valigurová, Andrea (referee)
Members of the group Archamoebae are free-living or endobiotic amoeboid flagellates and amoebae. They live in anoxic or microoxic habitats, and their mitochondria have been reduced. They were originally thought to lack mitochondria and represent one of the earliest eukaryotes. However, this hypothesis has been refuted, and now it is evident that the Archamoebae belongs to the lineage Conosa within the supergroup Amoebozoa, together with aerobic slime molds (Macromycetozoa) and variosean amoebae and flagellates. Relatively simple microtubular cytoskeleton is a characteristic feature of Archamoebae. It consists of a single basal body from which a flagellum arises, lateral root, and microtubular cone. Cytoskeleton of aflagellated genera has been completely reduced. About 350 species names of Archamoebae have been created so far. However, most descriptions were based on inadequate morphological features. The identity of numerous species is uncertain, and many of them are likely synonymous. Another problem is a small amount of available molecular data. During our project, we have substantially improved the dataset of DNA sequences of archamoebae. On the basis of molecular and morphological data, we described 13 new species. We showed that genus Rhizomastix belongs to Archamoebae and displays a new type...
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Diversity and phylogeny of Archamoebae
Zadrobílková, Eliška ; Čepička, Ivan (advisor) ; Kostka, Martin (referee) ; Valigurová, Andrea (referee)
Members of the group Archamoebae are free-living or endobiotic amoeboid flagellates and amoebae. They live in anoxic or microoxic habitats, and their mitochondria have been reduced. They were originally thought to lack mitochondria and represent one of the earliest eukaryotes. However, this hypothesis has been refuted, and now it is evident that the Archamoebae belongs to the lineage Conosa within the supergroup Amoebozoa, together with aerobic slime molds (Macromycetozoa) and variosean amoebae and flagellates. Relatively simple microtubular cytoskeleton is a characteristic feature of Archamoebae. It consists of a single basal body from which a flagellum arises, lateral root, and microtubular cone. Cytoskeleton of aflagellated genera has been completely reduced. About 350 species names of Archamoebae have been created so far. However, most descriptions were based on inadequate morphological features. The identity of numerous species is uncertain, and many of them are likely synonymous. Another problem is a small amount of available molecular data. During our project, we have substantially improved the dataset of DNA sequences of archamoebae. On the basis of molecular and morphological data, we described 13 new species. We showed that genus Rhizomastix belongs to Archamoebae and displays a new type...
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Diversity of the genus Monocercomonoides
Vlasáková, Jitka ; Hampl, Vladimír (advisor) ; Kostka, Martin (referee)
Oxymonads (Excavata, Preaxostyla) are a group of anaerobic endobiotic flagellates living primarily in guts of xylophagous insects (cockroaches and termites). Some representatives of the genus Monocercomonoides belonging to the morphologically simplest family Polymastigidae have been described also from the guts of vertebrates. Oxymonads are a group of protist in which mitochondrion has not been proven yet. In this work, we have sequenced gene fo SSU rRNA of two strains of Monocercomonoides and performed phylogenetic analysis of oxymonads. Five selected strains Monocercomonoides isolated from different hosts and distantly related on the phylogenetic tree were studied by using light (DIC and protargol staining) and transmission electron microscopy. The aim was to find differences between these strains. We have focused primarily on the morphology of the nucleus, appearance of the endoplasmic reticulum and structure of the fibre R1. We were able to distinguish the strains by the position of karyosome (central and parietal) and the number of microtubules in the R1 fibre (6-12) and we assume that they represent separate species. The phylogenetic position and appearance of the strains NAU3 were so different that it may represent a new genus. Mitochondria or double-membrane bounded organelles have not been...
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Diversity of free-living diplomonads
Rmoutilová, Eva ; Čepička, Ivan (advisor) ; Kostka, Martin (referee)
Order Diplomonadida belongs to the supergroup Excavata and comprises both free-living and endobiotic protists. Until recently, research on diplomonads was focused mainly on endobiotic representatives, particularly the parasite Giardia intestinalis, which has been the object of interest of many studies. Diplomonads are anaerobic protists that lack aerobic mitochondria. Instead, they possess reduced mitochodnrial derivates - hydrogenosomes or mitosomes. According to the morphology, the diplomonads are divided into unizoic (single karyomastigont) and diplozoic ones (doubled karyomastigont). Evolution of the cell morphology of diplomonads still remains unclear, and a thorough study focused on free- living diplomonads can help to elucidate this problem. Besides, the diplomonads are interesting because many secondarily free-living representatives of this group exist. This study is focused on the phylogeny a morphology of free-living diplomonads. We determined 65 new SSU rDNA sequences, mainly from free-living diplomands. Phylogenetic analyses showed genera Trepomonas and Hexamita as well as unizoic diplomonads non- monophyletic. Also, several diplomonad lineages containing both free-living and endobiotic species were recovered. We conducted a detailed study of morphology of two genera, Trepomonas and...
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Diversity of anaerobic ciliates
Nováková, Ludmila ; Čepička, Ivan (advisor) ; Kostka, Martin (referee)
Ciliates (Ciliata) are single-celled eukaryotic organisms belonging to the large group Alveolata. Ciliates are classified to eleven classes. Anaerobic/microaerophilic representatives belong to classes Armophorea, Litostomatea, Plagiopylea, Oligohymenophorea, and Prostomatea. The mitochondrion of the anaerobic ciliates has been tranformed to hydrogenosome. The anaerobic ciliates are characteristic for the presence of methanogenic symbionts in the cytoplasm near hydrogenosomes. Anaerobic flagellates are free-living or they live as commensals, mutualists or parasites in the digestive tract of animals including humans. The true diversity of anaerobic ciliates is still not fully understood. The reason is that only sequences of described ciliate species are usually included into phylogenetic analyses. However, many environmental sequences representing considerable part of known molecular diversity of ciliates have been published as well. The aim of this work was to obtain and analyze sequence data of anaerobic free-living ciliates. We have determined SSU rDNA sequences of 32 different freshwater and marine strains of ciliates. Phylogenetic analyses showed that the strains belonged mostly to the classes Armophorea, Plagiopylea and Oligohymenophorea. The strain LIVADIAN belonged, together with genera...
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Diversity of the genus Blastocystis (Stramenopiles)
Lorencová, Markéta ; Čepička, Ivan (advisor) ; Kostka, Martin (referee)
Although the genus Blastocystis is only little known, it has recently attracted much attention of protistologists and parasitologists. Similarly to the related opalines and proteromonads, Blastocystis is anaerobic and lives endobiotically in intestines of many animals. On the other hand, members of the genus have completely lost flagella. Therefore, the phylogenetic position of Blastocystis had been puzzling for a long time. B. hominis is one of the most common intestinal parasites of humans and has been found also in a wide variety of animals. It is highly prevalent not only in the developing nations, but also in the developed countries. Its enormous genetic diversity, pathogenic and zoonotic potential (B. hominis is often associated with irritable bowel syndrome) make from B. hominis an important emerging pathogen.
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Evolution of Retortamonadida (Eukaryota: Excavata: Fornicata)
Smejkalová, Pavla ; Kostka, Martin (referee) ; Čepička, Ivan (advisor)
Retortamonads (Retortamonadida; genera Chilomastix and Retortamonas) are a small group of protists comprising intestinal commensals of both vertebrates and invertebrates and one free-living species of the genus Chilomastix. Molecular phylogenetic studies showed that retortamonads are closely related to diplomonads, Carpediemonas, Dysnectes, Hicanonectes, Kipferlia and two undescribed lineages of free-living Carpediemonas-like organisms, together forming the monophyletic excavate group Fornicata. For a long time Retortamonadida have been assumed to be a monophyletic group. However, first molecular phylogenetic study including sequence data from both Retortamonas and Chilomastix suggested that Retortamonadida are paraphyletic and that diplomonads branch within Retortamonadida. Retortamonads still remain poorly studied protist group and their phylogeny is unclear. We sequenced and analysed SSU rDNA of ten Retortamonas and four Chilomastix SSU rDNA sequences. In addition, we sequenced SSU rDNA of an undescribed enteromonad lineage. The phylogenetic tree of Fornicata was largely unresolved and the phylogenetic position of the genus Chilomastix remained unclear. On the other hand, the genus Retortamonas and diplomonads formed a robust clade. Retortamonas sequences split into three host-specific lineages. The...
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