Quorum sensing
Japanese: クォーラムセンシング
A mechanism by which microorganisms sense their own cell density and collectively alter gene expression when a threshold is exceeded. Intercellular communication mediated by signal molecules.
Quorum sensing is a mechanism by which microorganisms sense their own density and collectively change behavior when their numbers reach a threshold. 'Quorum' means the minimum number needed for a legislative body to act—a system of 'act when enough allies have gathered.'
Microorganisms secrete signal molecules called autoinducers. As surrounding peers release the same molecules, signal concentration rises with density. When it exceeds a threshold, collective behaviors like biofilm formation or toxin production begin.
Single-celled microorganisms possess the ability to 'count.' This invites us to reconsider microbes not as passive entities but as agents that perceive and make decisions about their environment.
Even within fermented foods, microorganisms may be exchanging signals. Conversations we know nothing about may be taking place inside a miso barrel.