Abstract

Many animals often display an acute stress response called “fight-or-flight” when they perceive a threat. As the name suggests, the “fight-or-flight” response enables animals to physically fight or run away when faced with danger. In my biolunch, I will argue that bacteria have similar acute stress responses when they face chemical or mechanical stress. In particular, I will argue that biofilm bacteria can use directed motility in their responses to clinical antibiotics as if they are fighting with antibiotic-producing microbes. When exposed to a well-defined and stable gradient of antibiotics, biofilm bacteria actively move up the gradient, and this perplexing behaviour can be recapitulated when they meet an antibiotic-producing species growing in their neighbourhood. But they can also flee if that is the most appropriate strategy to respond to stress. In particular, I will argue that biofilm bacteria use bioluminescence coupled with dispersal as a response to acute changes in fluid flow. While the field of bacterial bioluminescence has been dominated by the paradigms of “quorum sensing” (i.e. density-dependent regulation) and “constant glow”, these ideas emerged from studies that focus on planktonic bacteria only. I will argue that when attached to each other in surface-attached communities, bacteria flash collectively before dispersing, in a way that is not consistent with canonical density-dependent regulation. If you arrive early, you will note this biolunch will start in nonorthodox way. I will introduce you to the book “Genesis and Development of a Scientific Fact” by Ludwik Fleck, where the author challenges the idea that “facts are facts”, and I will briefly discuss how we may benefit from his concerns.