Morphology-dependent motility of bacteria in porous media: The Long and Short of it

Abstract

Microbial activity in the natural world relies on migration through disordered three-dimensional porous media. Bacterial communities display a wide variety of cell morphologies, yet little is known about how cells with these diverse shapes migrate differently through the porous space. This study builds on recent work proposing a hopping-and-trapping pattern of motility constrained by pore geometry, in contrast to the previous assumptions of run-and-tumble motility carried over from studies in bulk liquid. We find length-dependent swimming patterns with discrete regimes of motility, in agreement with the phase duality of the hopping-and-trapping theory. As cell length increases, the given confinement becomes more of an obstacle to navigation through the pore space, and both translational and rotational freedom decrease accordingly. The reptation of semi-rigid bodies in directed paths bears a remarkable similarity to dynamics of living active polymer systems. This work therefore contributes to realistic principles for predicting cellular migration in natural and nature-like environments.