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Loss of excavate features in Excavata
Pavlátová, Magdaléna ; Čepička, Ivan (advisor) ; Němcová, Yvonne (referee)
Excavata is a supergroup of protists belonging to the Eukaryota domain. It is a very diverse taxon that comprises free-living organisms, commensals, and also parasits of animals and humans. Excavata is divided into two main lineages, Metamonada and Discoba, but from the morphological point of view the group Malawimonadida should belong here as well. The internal relationships as well as the monophyly of excavates have not been satisfactorily elucidated yet. The last common ancestor of excavates, perhaps even of all eukaryotes, had a ventral feeding groove, which was associated with a recurrent flagellum. This organism also possessed certain cytoskeletal structures that supported the ventral groove and vanes on the recurrent flagellum. These features have been preserved in some excavates to this day. However, the ventral groove has been reduced or lost in many lineages during the evolution and these representatives, which I refer to as non-excavate excavates, prevail. The aim of this thesis is to describe the ultrastructure of particular lineages of non-excavate excavates and to compare their cytoskeletal system with the cytoskeleton of typical excavates. The loss of excavate features in these lineages is discussed. Key words: excavate, non-excavate excavate, typical excavate, ultrastructure,...
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