,
9 tweets,
2 min read
Read on Twitter
Loki decloacked! biorxiv.org/content/early/… The amount of work described in manuscript represents a monumental effort, of which the importance cannot be understated! A thread. 
Obtaining stable Loki co-culture is the result of a 12-year (!!!) effort. This work shows that Loki is an aminoacid-fermenting hydrogen-producing heterotroph. Observed symbiotic interaction is compatible with recent syntrophic model for eukaryogenesis. nature.com/articles/s4156…
Doubling time of Loki was 14–25 days. Let that sink in for a moment....
The COMPLETE Loki genome confirms that it closely matches with Loki MAGs that were previously published by several labs. Hence, eukaryotic-like genes ("ESPs") NOT the result of binning contamination as suggested by some.
Loki cells are relatively small (~0,5 um), and produce unique, membrane-based protrusions of unknown function, possibly involved in sustaining syntrophic interactions, or cell attachment. Small cell size is in line with previous report from Knittel et al aem.asm.org/content/71/1/4…
Loki cells seemingly lack intracellular features, suggesting that Loki ESPs such as actin, profilin and gelsolin homologs are involved in membrane remodelling (e.g. formation of protrusions). Important to note that Loki lacks ESPs such as TRAPP, Sec23/24 & coatamer homologs.
The phylogenetic support for Loki+eukaryotes reported in this manuscript is in line with recent reports from several labs (including my own group), but needs to be carefully assessed with regard to more robust phylogenetic methods and better taxonomic sampling.
This work opens the door to cultivation efforts of other Asgard archaea. Characterisation of common and specific features of Asgards, especially of those closer related to eukaryotes, will be paramount for refinement of eukaryogenesis models.
A 12-year effort... Doubling time of 14-25 days... hopefully there are other Asgard lineages that turn out to be more tractable with regard to cultivation!
