In this project, we use acylated homoserine lactones (AHLs), signaling
molecules used for [http://en.wikipedia.org/wiki/Quorum_sensing quorum sensing] in gram negative bacteria.
Senders express LuxI or similar enzymes, which catalyze the production
of AHLs, under the control of a constitutive (Tet) promoter. Each cell
thus generates AHL more or less at a constant rate. AHL can freely
permeate cell membranes and are detected by neighboring cells.
Receivers constitutively express LuxR proteins (or a similar
ortholog), the protein that detects AHL concentrations. When AHLs bind
LuxR proteins, the AHL-LuxR complex activates the Lux promoter. The
threshold [AHL] at which switching occurs is determined by the
affinity of AHL for the particulr LuxR ortholog.
about quorum sensing)