Mechanical limitations of bacterial motility mediated by growing cell chains

Abstract

Many bacterial species are able to expedite colony expansion through active motility of the cells. A unique mode of colony expansion on a substrate surface recently discovered in a pathogenic bacterium Clostridium perfringens, surprisingly, does not depend on motility in single cells. Specifically, daughter cells maintain end-to-end connections after cell division, amounting to long chains of cells that continuously elongate as individual cells grow and divide. In principle, such cell growth-driven motility would accelerate as cell divisions increase the number of cells in a chain, and the tip of a long chain could potentially reach a very high speed.