Hello everyone,
I was involved in a recent study where we found a new form of social motility or swarming-like behavior in the archaeal species Haloferax volcanii. If you are not familiar with the idea of swarming in microbes, it is very interesting and something good to know about!
We usually think about swarming in insects, or similar behaviors in animals like schools of fish, herds of buffalo, etc.. But microbes undergo similar activities as well. One well known example is the soil species Myxococcus xanthus that is able to prey upon nearby colonies of other bacteria. M. xanthus cells form waves or ripples of cells (like wolf-packs) that travel through and lyse cells of the prey species (there are some good videos of this on YouTube).
If you are not familiar with Haloferax volcanii, this is an archaeal species that was first isolated from mud in the Dead Sea in the 1970's. H. volcanii is a halophile, so it lives at high salt concentrations. This is the first time that a collective activity like those seen in M. xanthus (and some other bacteria) has been seen in an archaeon. This is interesting because archaea are more closely related to eukaryotes than they are to bacteria.
The best way to look at the behavior is by looking at the time-lapse movies in the paper:
http://www.biomedcentral.com/1741-7007/12/65
http://www.biomedcentral.com/content/pdf/s12915-014-0065-5.pdf (direct link to PDF)
Though the behavior was observed, we do not yet know if there are any associated functions. Does anyone have any ideas as far as why the cells are coordinating their actions? Maybe it is a type of collective-feeding like in M. xanthus? It seems there is likely a function or ecological role for the swarming behavior, since it is likely an energetically costly activity that involves many genes (controlling chemotaxis, motility, etc.).
