Speaker
Description
We use dynamical self-consistent field-theory simulations of interacting, self-propelled rods to study the fascinating time-dependent, inhomogeneous structures observed during the growth of a colony of twitching Pseudomonas aeruginosa bacteria confined at the interface between a glass substrate and agar. These collective patterns in colony growth are relevant to early-stage biofilm formation, to the spread of infection, and to our understanding of the surface-motility mechanism of these bacteria. Our focus is on colony fingers, which are long-lived, compact, dense domains of aligned bacteria which form at, and grow out from, the leading edge of the growing bacteria colony. We investigate how the strength of the self-propulsion and the density of bacteria affect the shape and speed of the fingers, as well as the degree of bacteria alignment within the fingers. In the presence of self-propulsion, a perturbation of an initially flat colony edge will evolve into a long finger. By introducing a random spatial variation of the glass-agar adhesion strength into the simulation, we produce finger structures and dynamics similar to what is seen in experiment.
