Modeling E. coli tumbles by rotational diffusion. Implications for chemotaxis.

ABSTRACT: The bacterium Escherichia coli in suspension in a liquid medium swims by a succession of runs and tumbles, effectively describing a random walk. The tumbles randomize incompletely, i.e. with a directional persistence, the orientation taken by the bacterium. Here, we model these tumbles by an active rotational diffusion process characterized by a diffusion coefficient and a diffusion time. In homogeneous media, this description accounts well for the experimental reorientations. In shallow gradients of nutrients, tumbles are still described by a unique rotational diffusion coefficient. Together with an increase in the run length, these tumbles significantly contribute to the net chemotactic drift via a modulation of their duration as a function of the direction of the preceding run. Finally,

SUBMITTER: Saragosti J 

PROVIDER: S-EPMC3329434 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature