September 17, 2010 § 1 Comment
So this week seems to be turning out to be cooperation week. We talked about cooperative behavior of the proteins that make up the cytoskeleton on Monday, cooperation in breeding behavior in birds on Wednesday, and now it’s time to talk about cooperative behavior in bacteria. If only I’d planned it in advance. Ah well; can’t have everything.
You know, of course, that in the wild bacteria do not typically live in monocultures: different varieties of bacteria both compete and collaborate, and the complex interactions that result are not easy to study. A number of labs have been working on developing well-defined synthetic communities to ask questions about how communities evolve. The Silver lab has now taken a rather different approach (Wintermute and Silver 2010, Emergent cooperation in microbial metabolism. Molecular Systems Biology 6: 407 PMID: 20823845), by exploring the interactions among 46 different metabolically impaired strains of E. coli and rationalizing the results in terms of a flux-balance-analysis model of interacting strains.
What interested Wintermute and Silver was the fact that bacterial communities can perform all kinds of important metabolic tricks that individual species can’t manage. This is not hard to understand, or at least to imagine that you understand: one species finds an efficient way to produce rare metabolite A, another species develops an efficient way to produce rare metabolite B, when you mix the two together they both have the advantages of a supply of both A and B, but they’ve effectively halved the cost of production (making all those enzymes) by sharing. But is that really how it works?