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Species delimitation in lobose amoebae
Foučková, Martina ; Čepička, Ivan (advisor) ; Škaloud, Pavel (referee)
Lobose amoebae - amoebas that create lobopodia - are distributed among the supergroup Amoebozoa, Excavata, Rhizaria and the genus Anaeramoeba (Eukaryota incertae sedis). For their species delimitation (i.e., pinpointing boundaries between particular species), morphological features are used most often, such as the size and shape of the cell, appearance of the hyaloplasm, pseudopodia and subpseudopodia, granuloplasm with cytoplasmatic inclusions, number and size of nuclei, shape of the uroid and cysts if present. The morphological characteristics are easily documented using a light microscope. Ultrastructural features, such as the ultrastructure of nuclei and nucleoli, surface structures, and organelles, are used as well. Nowadays, species are also described and distinguished employing molecular methods, mostly analyses of the SSU rRNA and actin genes, COI barcoding, and ITS sequences, which allow detection of cryptic species. Before the sequencing era, RFLP, RAPD and isozymes methods were also used for delimitation of species. This thesis focuses on particular methods and features used for species delimitation of lobose amoebae on the basis of 125 selected species belonging to Amoebozoa (orders Acanthamoebida, Pellitida, Himatismenida, Dermamoebida, Thecamoebida, Vannellida, Dactylopodida,...
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Evolution of anaerobic Heterolobosea
Pánek, Tomáš ; Čepička, Ivan (advisor) ; Oborník, Miroslav (referee)
Heterolobosea is a group of mainly free-living amoebae, flagellates and amoeboflagellates closely related to Euglenozoa and Jakobida (supergroup Excavata). At least two heterolobosean lineages have reduced their mitochondria and live in low concentrations of oxygen (Psalteriomonadidae and extremely halophilic Pleurostomum). Moreover, some other presumably anaerobic species have been described in aerobic heteroloboseid genera, but their sequence data are still missing. The aim of this study is to recognize the diversity and phylogenetic position of both already described and novel non-hypersaline anaerobic heteroloboseans. We have isolated and cultivated 34 strains of free-living heterolobosean flagellates, amoebae and amoeboflagellates from freshwater, brackish and marine microoxic/anoxic habitats. 33 of these strains constitute a single clade (Psalteriomonadidae). We recognize 2 new genera and 3 new species. Phylogenetic analysis of SSU rDNA showed the genus Percolomonas is polyphyletic. The similar morphology of species formally placed within the genus Percolomonas is probably plesiomorphic. Finally, the marine strain PC4AM is morphologically unique and its morphology can not be compared with other heteroloboseans and eukaryotes. It is probably the most derived heterolobosean. Its cell structure...
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