Reporter assays of PLux-Lacltandem GFP. The results show the changes in the fluorescence intensities of the cultures with pSB-GFP, Placq-GFP, or PLuxR-LacItandem-GFP dependent on the input of 1 mM IPTG and 4.5 nM AHL. Cells were cultured for 8 hours after the induction. In the culture with PLuxR-LacItandem-GFP, the GFP expression was turned on in the presence of both 1 mM IPTG and 4.5 nM AHL. When neither of the inducers was added, GFP expression was turned off. In the presence of the both inducers, culture with PLuxR-Lacltandem-GFP showed 5.7-fold higher fluorescence intensity than that in the absence of the both inducers. The culture with pSB-GFP, which does not express GFP, was used as a negative control. The culture with Placq-GFP, which constitutively expresses GFP, was used as a positive control. The assays were performed in triplicate. Error bars indicate the standard deviation.