Figure 2.

VqmA exhibits activity in the absence of its cognate AI, and the LasR QS receptor does not. Shown is normalized reporter activity from E. coli harboring the VqmA/PvqmR-lux or the LasR/PlasB-lux system. Left, E. coli carrying one plasmid with PvqmR-lux and a second plasmid with pBAD-vqmA. The strain represented by the bar designated Control lacks the pBAD-vqmA plasmid. Right, E. coli carrying one plasmid with PlasB-lux and a second plasmid with pBAD-lasR. The strain represented by the bar designated Control lacks the pBAD-lasR plasmid. All strains were grown in the presence of 0.075% arabinose and in the absence or presence of the designated AI (20 μm DPO or 1 μm 3OC₁₂-HSL). AIs were added to the control strains. Data are represented as mean ± S.D. (error bars) with n = 3 biological replicates. AU, arbitrary units.