From 2007.igem.org

Reporter cell: this cell is designed to test the concentration of AHL signal. In this cell, LuxR gene under the control of tet promoter could produce LuxR protein which could activite the following Lux pR promoter when binding to certain amount of AHL signal, thus GFP expressed to make this cell green within the view of a fluoresence microscope. The intensity of fluoresence could be measured by a fluoresence spectrophometer to decide the concentration of AHL signal roughly.