Electron dumping: Older than multicellular life

[Patty]

I have just returned from the ASM meeting in Toronto. 10,000 participants (!!) .... mostly infectious disease people but also people like myself who are general micro people.

The most memorable talk was about bacterial nanowires. Under conditions of limited electron acceptor concentration ("low O2"), it turns out that bacteria will build electro-conductive "wires" between each other, looking for a place to dump their electrons.

Many different genera do this across Bacteria.

Cyanobacteria will attach such "wires" to an anode.

Bradyrhizobium will do this when in symbiosis with legume crops.

I expect (but was not told during the talk) that in our intestinal biofilms (low O₂ conditions, huge numbers of bacteria) that such wires will form.... possibly even to human cells. This would mean that our NADH electron carriers (which feed into our electron transport chains in order to make ATP), at least the ones in intestinal tissues, might be charged (accept electrons) off of .... bacterial catalysis of organic matter! This means that when you were young and you had the impression that bacteria were doing the digestion "for you," that you may have been partially right!

This last idea was not presented during the talk, but it would be consistent with everything that was presented, and I expect it is just a matter of time before such a mechanism of inter-kingdom electron transfer is published.

Cool. Beans.

[Orstio]

Cool.  Can you describe how the electron dumping works?  I don't know about how getting rid of electrons helps an organism live -- and Googling for "electron dumping" actually brings up this topic first....