Talmudic Question #77

Both marine phages and predatory protists prey on bacteria. Something has been written about how phages may help bacteria escape protist predation. Click here for an erudite treatment. Is something known about the converse, namely communication between protists and phages? For instance, do protists make compounds that diminish predation by phages, e.g., by making phage-inhibitory substances?

Comments

[belstaff jacket]

I think that is a good remark, but, does it discard the co-evolution of the eukaryote RNA interference with phagues and bacterial transposable elements?

[Alberto Carmona Bayonas]

Mark, I think that is a good remark, but, does it discard the co-evolution of the eukaryote RNA interference with phagues and bacterial transposable elements? In fact, it is a single virus considered. The eukaryote RNA interference system does not either protect us from all our pathogenes... I think the basic toolkit of the RNA interference does not prevent the system to react against interspecies viruses.

In fact, it could be interesting to analyze this hyphotesis in light of the tug of war following the so-called "intron catastrophe".

http://www.biology-direct.com/content/1/1/22

If eukarytes have been exposed to this type of selfish elements for a while, it should be feasible to consider complex scenarios, such as symbiosis based on the shelter of the cytoplasmatic protection.

[Mark O. Martin]

It's interesting to consider this in the context of bacterial-bacterial predation! It's not all about the phages (though they are abundantly cool).

Alberto, I believe that there is some evidence from Wolbachia for phage interacting *within the cytoplasm* of the host cell!

http://www.plospathogens.org/article/info%3Adoi%2F10.1371%2Fjournal.ppat.0020043

[Alberto Carmona Bayonas]

Maybe the bacterial endosymbionts of eukaryotes were trying to protect themselves from phagues. If the endosymbiont proved to be evolutionary useful, the host RNA interference system could evolve to counteract lysogenic viruses and other bacterial transposable elements. In fact, it could make sense to find a microbial society based on syntrophy and "inmmunologial" protection.

[Nathan Myers]

This question seems to suggest that we might be able to tell who owns the phages by looking at who have co-evolved with them for maximum benefit. Or who the phages own...