Laboratory of Evolutionary Protistology
The Laboratory of Evolutionary Protistology (LEP) was established in 2000 as a joint project of the Institute of Parasitology and Faculty of Biological Sciences, University of South Bohemia. The laboratory is designed to study molecular evolution of single celled eukaryotes, mainly those that have been involved in the process of secondary endosymbiosis. LEP is supported by grants covering particular projects (see section Other).
McQuaid J.B., Kustka A.B.,
Horák A., Mccrow J., Karas B.J., Zheng H., Kindeberg T., Andersson A.J., Barbeau K.A., Allen A. (2018) Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms Nature
Lukeš J. (2015) The Organellar Genomes of Chromera and Vitrella, the Phototrophic Relatives of Apicomplexan Parasites Annual review of microbiology
Documents to download:
Woo Y., Ansari H., Otto T.D., Klinger C.,
Kolísko M., Michálek J., Saxena A., Shanmugam D., Tayyrov A., Veluchamy A., Ali S., Bernal A., Del C., Cihlář J.,
Flegontov P., Gornik S.,
Janouškovec J., Katris N., Mast F., Miranda-Saavedra D., Mourier T., Naeem R., Nair M., Panigrahi A., Rawlings N., Regelado E., Ramaprasad A., Samad N.,
Tomčala A., Wilkes J., Neafsey D., Doerig C., Bowler C., Keeling P., Roos D., Dacks J., Templeton T., Waller R.,
Oborník M., Pain A. (2015) "Chromerid genomes reveal the evolutionary path from photosynthetic algae to obligate intracellular parasites " eLife
Documents to download:
Allen A., Dupont C.,
Horák A., Nunes-Nesi A., Mccrow J., Zheng H., Johnson D., Hu H., Fernie A., Bowler C. (2011) Evolution and metabolic significance of the urea cycle in photosynthetic diatoms. Nature
Kořený L., Sobotka R.,
Janouškovec J., Keeling P.,
Oborník M. (2011) Tetrapyrrole synthesis of photosynthetic chromerids is likely homologous to the unusual pathway of apicomplexan parasites. Plant Cell
Current research projects
Evolution of parasitism in apicomplexan parasites (Sporozoa; Apicomplexa)
We are getting more interested in the evolution of parasitism in Apicomplexa. We recently published a novel hypothesis about the evolution of obligate parasitism in Apicomplexa from the photoparasitic ancestor (Oborník 2020). We suppose that the phototrophic ancestor of apicomplexan parasites had already combined phototrophy and parasitism, as the chromerid alga Chromera velia likely does. It appeared that C. velia invades coral larvae and causes the death of a substantial portion of the larval population. The photoparasitic lifestyle of the chromerid is allowed by the translucency of the larvae making thus photosynthesis possible. We suppose the photoparasite acquires nitrogen preferably from the host because it can fix the organic carbon by its own photosynthesis.
Chromerids Chromera velia and Vitrella brassicaformis, alveolate algae isolated from Australian stony corals, are the main objects of our scientific interest (Moore & Oborník et al., 2008; Oborník et al., 2012). These algae are believed to represent the closest known phototrophic relatives to apicomplexan parasites (Moore & Oborník et al., 2008; Oborník et al., 2009; Janouškovec et al., 2010; Woo et al, 2015). We have so far studied chromerid ultrastructure, morphology, life cycles (Oborník et al., 2011, 2012), plastid genomes of both algae (Janouškovec et al., 2010) as well as their mitochondrial genomes (Flegontov et al., 2015). We have participated on the sequencing of nuclear genomes of chromerids as well (Woo et al., 2015). We suppose to continue with this research in the future.
It is well known that eustigmatophytes lack chlorophyll c in their photosynthetic complexes, although it is a pigment hallmark of algae with secondary red plastids. The same pigment deficiency we found in chromerid algae Chromera velia and Vitrella brassicaformis (Moore & Oborník et al., 2008; Oborník et al., 2012). In frame of sequencing of the plastid genome of Trachydiscus minutus, a new star on the biotechnology sky of production of polyunsatrurated fatty acids, we tested a hypothesis concerning tertiary origin of chromerid plastid. When the similar (C. velia) or even identical (V. brassicaformis) pigment composition in chromerids and eustigmatophytes is taken into account, it is likely and phylogenetics analyses support this idea that chromerid plastid is derived from eustigmatophyte through a tertiary endosymbiosis (Ševčíková et al., 2015).
Synthesis of tetrapyrroles
Tetrapyrroles heme and chlorophyll are essential for life on Earth. We are interested in evolution of the heme biosynthetic pathway, particularly in origins of involved enzymes and their intracellular localizations. We focus mainly on algae that have passed through a process of secondary endosymbiosis, such as chromerids, dinoflagellates, diatoms and cryptophytes, and at the end also apicomplexan parasites. We showed that phototrophic alga C. velia produces 5-aminolevulinate similarly to apicomplexan parasites from glycine and succinyl CoA in the mitochondrion. All other eukaryotic phototrophs synthesize this precursor from tRNA-GLU in the plastid, where the entire pathway is located. We study heme pathway also in other organisms such as Vitrella brassicaformis, Bigelowiella natans, Paulinella chromatophora, Glenodinium foliaceum and others.