We published a new paper (link) showing that the material properties of dead cells impacts microbial social interactions.
How do antagonistic bacteria coexist in crowded biofilms? Most contact killing studies focus on cellular and sub-cellular events over short time scales, showing that the abundance of ‘target’ cells (i.e., cells that are susceptible to attack) can rapidly decrease. These observations reinforce the idea that contact killing is a highly potent antagonistic strategy. Thus, for killer and target cells to coexist, the current assumption is that target cells must possess strain-specific, genetically controlled defense mechanisms. However, we found that physical consequences of cell death prevent further lethal attacks from occurring. Dead cell debris accumulates at the interfaces between killer and target cells, contact a physical barrier. The barrier separates killer and target cells, preventing contact and thus preventing contact killing. Our results indicate that while very effective at reducing the population of competing cells on first contact, contact killing can actually help antagonistic bacteria coexist.