Abstract

Bacteria often live as biofilms—surface-associated communities encased by an extracellular matrix—that are critical for microbial biology and their impacts on us. While we have a thorough understanding of how free floating bacteria use diverse stress responses to adapt to changing environmental conditions, we know surprisingly little about how they coordinate their responses as a collective in biofilms. For this biolunch, I will show you how submerged biofilms respond to quick changes in osmotic pressure. Surprisingly, biofilms quickly shrink or expand their volume in a coordinated fashion, as a response to hyper- or hypo-osmotic shocks, reminiscent of the osmotic stress responses of free floating bacteria. These changes in biofilm volume result in strong fluid flows that can impact other cells in the neighborhood: biofilm fluid flows can attract or repel free-floating bacteria. I will discuss the ecological implications of this unexplored biofilm behavior, and will argue that it is relevant to understand the recently documented self-sustained “growth oscillations” in confined biofilms. Come if you enjoy pretty movies and the wonders of the microbial world.