Collective gradient sensing by swimming bacteria without clustering

Abstract

We demonstrate that bacterial cells enhance the taxis performance by collective migration originating from the cellular alignment interaction without apparent clustering. We confineSalmonellacells in a shallow channel and evaluate the thermotaxis response to local heating and diffusion. By combining cell tracking analysis and numerical simulation based on simple modeling, we show that the alignment interaction suppresses orientation fluctuation, strengthens migration bias, and also prevents the dispersion of accumulated population. The results show a prominent example of how a collective motion of active matter implements a biological function.