Long range electrochemical signals attract bacteria to biofilms indiscriminately
Another fascinating paper from Gürol Süel and a team of researchers in the US
A new paper in Cell shows evidence for interspecies communication using ionic signals. A Bacillus subtilis biofilm was able to attract motile Pseudomonas aeruginosa cells.
This pioneering group of researchers again raises exciting questions about community dynamics within biofilms as well as drawing comparisons nerve cell signalling as they did in their previous work covered by Elisabeth Bik and myself in the npj Biofilms and Microbiomes Community.
Bacteria are clearly not as simple as we thought!
The paper has already attracted a lot of attention, Helen Blackwell talked to Ed Yong from The Atlantic.
“This is amazing work that reshapes how we think about bacterial interactions and biofilm formation,” says Helen Blackwell, from the University of Wisconsin-Madison, who was not involved in the study. “It shows us a simple and generic way for many different bacteria to interact thorough electrical signals.”
The implications of this work are very exciting. Süel and his team show this working between B. subtilis and Ps. aeruginosa but imagine which other species communicate to one another via electrical signals? Time will tell, but I'm guessing it will be a lot more.
- • Electrical signaling within biofilms attracts distant motile cells
- • Attraction is caused by membrane-potential-dependent modulation of tumbling frequency
- • Electrical signaling is generic, resulting in species-independent attraction
- • Attraction leads to incorporation of diverse species into a pre-existing biofilm
Bacteria residing within biofilm communities can coordinate their behavior through cell-to-cell signaling. However, it remains unclear if these signals can also influence the behavior of distant cells that are not part of the community. Using a microfluidic approach, we find that potassium ion channel-mediated electrical signaling generated by a Bacillus subtilis biofilm can attract distant cells. Integration of experiments and mathematical modeling indicates that extracellular potassium emitted from the biofilm alters the membrane potential of distant cells, thereby directing their motility. This electrically mediated attraction appears to be a generic mechanism that enables cross-species interactions, as Pseudomonas aeruginosa cells also become attracted to the electrical signal released by the B. subtilis biofilm. Cells within a biofilm community can thus not only coordinate their own behavior but also influence the behavior of diverse bacteria at a distance through long-range electrical signaling.
Keywords: biofilm; electrical signaling; motility; multispecies; membrane potential; ion channel; bacterial communities; long-range signaling; tumbling frequency; single cell trajectories