Expression of promoter:: luxCDABE fusions for OHL responsive genes identified by K56-I2 Tn 5 -OT182 mutagenesis. The promoter fusions in pMS402 were introduced into strains K56-2 (●), K56-dI2 with no OHL (▼), K56-dI2 with 25 nM OHL (▲) and K56-R2 (■). Strains were grown in triplicate in 96 well microtitre plates for 24 hours. Luminescence and optical density were measured at various timepoints and the activity of the promoter was calculated as CPM/O.D. A. pCPI301 (cepI), B. pAID301 (aidA), C. pAYL301(acyltransferase), and D. pHMV301(phuR).