ICOP 2017 in Prague: Getting Around

This summer we are organizing the 15th International Congress of Protistology in Prague, Czech Republic. For more information please visit the congress web page, join the Facebook event, or follow the International Society of Protistologists and particularly the #ICOP17 hashtag on Twitter. Here I made two simple maps which might help you to plan your stay in Prague. For official information on public transport in Prague as well as for finding a particular connection you can use the public transport company page. Please, feel free to contact me with any (nonofficial =) ) questions about Prague or the congress.

map

Arginine deiminase pathway enzymes: evolutionary history in metamonads and other eukaryotes

Background

Multiple prokaryotic lineages use the arginine deiminase (ADI) pathway for anaerobic energy production by arginine degradation. The distribution of this pathway among eukaryotes has been thought to be very limited, with only two specialized groups living in low oxygen environments (Parabasalia and Diplomonadida) known to possess the complete set of all three enzymes. We have performed an extensive survey of available sequence data in order to map the distribution of these enzymes among eukaryotes and to reconstruct their phylogenies.

Arginine deiminase pathway enzymes: evolutionary history in metamonads and other eukaryotes

Arginine deiminase pathway enzymes: evolutionary history in metamonads and other eukaryotes. Graphical Abstract.

Result

We have found genes for the complete pathway in almost all examined representatives of Metamonada, the anaerobic protist group that includes parabasalids and diplomonads. Phylogenetic analyses indicate the presence of the complete pathway in the last common ancestor of metamonads and heterologous transformation experiments suggest its cytosolic localization in the metamonad ancestor. Outside Metamonada, the complete pathway occurs rarely, nevertheless, it was found in representatives of most major eukaryotic clades.

Conclusions

Phylogenetic relationships of complete pathways are consistent with the presence of the Archaea-derived ADI pathway in the last common ancestor of all eukaryotes, although other evolutionary scenarios remain possible. The presence of the incomplete set of enzymes is relatively common among eukaryotes and it may be related to the fact that these enzymes are involved in other cellular processes, such as the ornithine-urea cycle. Single protein phylogenies suggest that the evolutionary history of all three enzymes has been shaped by frequent gene losses and horizontal transfers, which may sometimes be connected with their diverse roles in cellular metabolism.

Continue reading (open access) here.