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Modeling microbial cooperation in challenging physical environments


Speaker: Marcus Roper, University of California, Berkeley
Location: 1147 MSB
Start time: Mon, Jan 10 2011, 1:10PM

Although the common conception of microbes is of isolated and individualistic cells, cells can also cooperate to overcome challenges on dispersal, growth or feeding in difficult physical environments. Highlighting two examples, I’ll show how new mathematical models reveal the benefits of inter-cellular cooperation and expose the developmental and stability barriers against cooperation, illuminating the ecology of important pathogens or model organisms. 1. Sclerotinia sclerotiorum is a devastating crop pathogen endemic to more than 40 species of crops across North America. Infections spread across and between fields by the ejection of airborne spores from mature fruiting bodies. The virulence of new infections is remarkable considering that individually ejected spores travel only a few mm before being stopped by air drag. Direct numerical simulations of the coupled dynamics of spores and the surrounding air show that hydrodynamic interactions between spores drive macroscopic winds that greatly enhance spore dispersal. 2. The large cells of filamentous fungi can harbor many different nuclei in a shared cytoplasm. Our experiments show that although having access to multiple genomes enables fungi to succeed in a huge variety of niches, keeping these genomes in stable well-mixed proportions requires constant active mixing of nuclei throughout the colony. Discrete network modeling then reveals the burden that maintaining this mixing places on cell architecture.

Refreshments will be available at 12:45 p.m.