Dissipative Shocks behind Bacteria Gliding

TL;DR

This paper develops a comprehensive nonlinear mechanical model to explain bacteria gliding motility, focusing on dissipative shocks at slime filament contact points, and finds that gliding and slime ejection velocities must be equal.

Contribution

It provides the first full nonlinear mechanical theory for bacteria gliding involving dissipative shocks at filament contact points.

Findings

Gliding velocity equals slime ejection velocity.

Dissipative shocks are essential in the propulsion mechanism.

The model aligns with observed bacteria behavior.

Abstract

Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.