Figure 4
“lux box 2” is required for repression of ainSR promoter-reporter by LuxR-3OC6-HSL. Fluorescence of cells harboring P ainS -gfp reporter pHK12 grown in SWTO to OD595 ~2.5. Strains with luxR ES114 or no luxR harboring P ainS -gfp reporter plasmids pHK156 (with lux box 1) or pHK12 (both lux boxes) were grown with 50 nM 3OC6-HSL (white bars) or no addition (grey bars). Strains harboring these reporters lack AHL synthases (∆luxI ∆ainS) and feedback regulation of luxR (litR::ermR Pcon -luxR). Bars indicate standard error (n = 3), and asterisk indicates a significant difference in reporter activity upon addition of 50 nM 3OC6-HSL (P < 0.05).
