Self-trapping of a single bacterium in its own chemoattractant

Physique de la Matière Condensèe, Collège de France - Paris, France

Received: 17 December 2003
Accepted: 12 March 2004

Abstract

Bacteria (e.g., E. coli) are very sensitive to certain chemoattractants (e.g., asparate) which they themselves produce. This leads to chemical instabilities in a uniform population. We discuss here the different case of a single bacterium, following the general scheme of Brenner, Levitov and Budrene. We show that in one and two dimensions (in a capillary or in a thin film) the bacterium can become self-trapped in its cloud of attractant. This should occur if a certain coupling constant g is larger than unity. We then estimate the reduced diffusion of the bacterium in the strong-coupling limit, and find .