Figure 2.

Demonstration of selective media and experimental setup. (A) Growth curves for monoculture QS⁺ (R) and QS^– (S) strains grown in QSM + 0.1% adenosine (selfish QS-selective medium). (B) Growth curves for R and S in QSM + 0.1% CAA + 1% BSA (group-beneficial QS-selective medium). In both QS-selective media, monoculture R grew substantially better than monoculture S. (C) Schematic of the competition studies performed herein. A QSI-resistant mimic (PAO1::mini-Tn7-GFP-Gm^R) and a QSI-sensitive mimic (ΔlasR, ΔrhlR, Tc^R) were mixed and grown in QS-selective media. Initial and final ratios of resistant/sensitive bacteria were calculated by counting colony forming units (CFUs) of resistant mimics on gentamicin-containing plates and CFUs of sensitive mimics on tetracycline-containing plates. Gm^R = gentamicin resistant; Tc^R = tetracycline resistant.