Speaker: Prof. Joceline Lega
From: Department of Mathematics, University of Arizona, Tucson
Date/Room/Time: Wednesday, December 1, 2004 / 117 Hayes-Healey Hall/ 5:15-6:15 PM

Tea begins at 3:30 PM in Room 257 of Hurley Hall

Title: A hydrodynamic model for the growth of bacterial colonies

Abstract:
Bacterial colonies growing on soft agar often display complex branched structures and collective motions involving many cells. I will present a model which consists of reaction-diffusion equations coupled to a hydrodynamic equation for the velocity field of the bacteria-water mixture, which captures such complex behaviors. I will show numerical results which illustrate how complex collective motions within a colony may destabilize its boundary and lead to the formation of branches. I will also present phase diagrams, which classify colony morphology as a function of the initial amount of nutrients on the plate and of the wetness of the agar. This work is joint with Thierry Passot (Observatoire de la Cote d'Azur, France).