Single-cell bacterial electrophysiology reveals mechanisms of stress-induced damage

TL;DR

This study introduces a novel method combining mathematical modeling and single-cell voltmeter techniques to measure and analyze bacterial membrane potential and stress responses in real-time.

Contribution

It develops a new quantitative framework for bacterial electrophysiology using an electric circuit analogy and a single-cell voltmeter, revealing mechanisms of stress-induced membrane damage.

Findings

Butanol acts as an ionophore disrupting membrane potential

Short-wavelength light causes membrane damage in bacteria

The method enables real-time, non-invasive measurement of bacterial PMF

Abstract

Electrochemical gradient of protons, or proton motive force (PMF), is at the basis of bacterial energetics. It powers vital cellular processes and defines the physiological state of the cell. Here we use an electric circuit analogy of an Escherichia coli cell to mathematically describe the relationship between bacterial PMF, electric properties of the cell membrane and catabolism. We combine the analogy with the use of bacterial flagellar motor as a single-cell "voltmeter" to measure cellular PMF in varied and dynamic external environments, for example, under different stresses. We find that butanol acts as an ionophore, and functionally characterise membrane damage caused by the light of shorter wavelengths. Our approach coalesces non-invasive and fast single-cell voltmeter with a well-defined mathematical framework to enable quantitative bacterial electrophysiology.