How bacteria count their numbers
Miller and Bassler reviewed quorum sensing: bacteria release autoinducer molecules and change gene activity once a threshold concentration is reached, controlling things like glow, virulence and biofilms.
As reported in: Miller, Bassler (2001). Quorum Sensing in Bacteria. Annual Review of Microbiology. doi:10.1146/annurev.micro.55.1.165
Abstract only