Abstract:The bacterial membrane potential is dynamic and plays important signalling roles. Yet, little is still known about the mechanisms of bacterial membrane potential dynamics regulation –owing in part to lack of appropriate research tools. Optical modulation of bacterial membrane potential could fill this gap and provide a new approach to studying and controlling bacterial physiology and electrical signalling. Here, we show that a membrane-targeted azobenzene (Ziapin2) can be used to photo-modulate the membrane potential in cells of the Gram-positive bacterium Bacillus subtilis. We found that upon exposure to blue-green light, isomerisation of Ziapin2 in the bacteria membrane induces hyperpolarisation. To investigate the origin of this phenomenon, we examined ion-channel-deletion strains and ion channel blockers. We found that in presence of a chloride channel blocker, or in absence of a potassium transporter, the hyperpolarisation response is attenuated. These results reveal that the Ziapin2 isomerisation can induce ion channel opening in the bacterial membrane and suggest that Ziapin2 can be used for studying and controlling bacterial electrical signalling. This new optical tool can contribute to better understand various microbial phenomena, such as biofilm electric signalling and antimicrobial resistance.

Biography: Tailise Souza did her PhD in cell biology and is now a Postdoc in Asally’s laboratory, at School of Life Sciences, University of Warwick. Her current work focus on bioelectricity of microorganisms like the Gram-positive bacteria Bacillus subtilis and the budding yeast Saccharomyces cerevisiae. Bioelectricity is an area of research now listed as a spotlight topic by BBSRC and her work in Asally lab aims to connect it to applications ranging from optical modulation of membrane potential to developing diagnostic tools for proliferative microorganisms. A member of the Policy Advisory Panel of the Biochemical Society, Tailise has also been engaging in increasing awareness of the threat that antimicrobial resistance poses to our society.