1. Electrical spiking in Escherichia coli probed with a fluorescent voltage-indicating protein.
- Author
-
Kralj JM, Hochbaum DR, Douglass AD, and Cohen AE
- Subjects
- Action Potentials, Escherichia coli genetics, Fluorescence, Fluorescent Dyes, Hydrogen-Ion Concentration, Ion Channels metabolism, Ion Transport, Light, Protons, Rhodamines metabolism, Rhodopsin chemistry, Rhodopsin genetics, Rhodopsins, Microbial, Spectrometry, Fluorescence, Stress, Physiological, Escherichia coli physiology, Membrane Potentials, Rhodopsin metabolism
- Abstract
Bacteria have many voltage- and ligand-gated ion channels, and population-level measurements indicate that membrane potential is important for bacterial survival. However, it has not been possible to probe voltage dynamics in an intact bacterium. Here we developed a method to reveal electrical spiking in Escherichia coli. To probe bacterial membrane potential, we engineered a voltage-sensitive fluorescent protein based on green-absorbing proteorhodopsin. Expression of the proteorhodopsin optical proton sensor (PROPS) in E. coli revealed electrical spiking at up to 1 hertz. Spiking was sensitive to chemical and physical perturbations and coincided with rapid efflux of a small-molecule fluorophore, suggesting that bacterial efflux machinery may be electrically regulated.
- Published
- 2011
- Full Text
- View/download PDF