Orthogonal microfluidic approaches reveal force-enhanced migration of bacterial populations on surfaces
Host-generated flow is expected to oppose bacterial migration by sweeping cells downstream, yet some bacteria can migrate upstream against the direction of flow. However, it is unclear how the magnitude of shear force influences upstream bacterial migration. Here, we use microfluidics to examine upstream migration of the human pathogen Pseudomonas aeruginosa under host-relevant shear forces…
Microfluidic experiments shed light on the impact of shear forces on the migration patterns of the human pathogen Pseudomonas aeruginosa. Contrary to expectations, increasing shear force was found to actually boost population-level upstream migration. This counterintuitive effect was linked to an uptick in twitching motility speed among single bacterial cells.
Microfluidic tracking showed that force-enhanced migration stemmed from a speedier twitching motility rate. The researchers employed microfluidic-based trigonometry to discover that the increase in speed correlated with the angle between the bacterial cell and the surface it was moving on. At lower shear forces, type IV pilus retraction produced a torque that tilted the cells vertically, restricting forward movement and reducing twitching speed.
In stark contrast, higher shear forces oriented cells horizontally, thereby facilitating faster twitching motion.
These findings provide a comprehensive understanding of how shear forces can boost bacterial motility and upstream migration. The results offer a framework for comprehending how host shear forces could facilitate the spread of bacterial infections.
Written by urgent.news from bioRxiv's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
