Fig. 6

Population A growth modulates Population C activity dependent on initial co-culture composition, AI-1 addition, and environment. Population A (E. coli PH04 pZE-phzAG-ptsH-DsRed) and Population B (E. coli PH04 pZE-phzMS) were co-cultured together at initial inoculation ratios as indicated on the x-axis and with nanomolar AI-1 concentrations as indicated in the legend. After overnight growth, 20 µL of the PYO producing co-culture (~ 1.5 OD₆₀₀) was added to a culture of ~ 0.2 OD₆₀₀ Population C (PH04 pCT10-pET-eGFP) with 200 µL final volume in fresh media. The tri-strain culture was then incubated for 4 h, and then measured for DsRed and eGFP fluorescence. A, B Raw DsRed fluorescence of the tri-strain co-culture at 4 h, indicating Population A composition in culture. C, D Average eGFP fluorescence fold over background of tri-strain co-culture, indicating Population C activity. E, F Average eGFP divided by average DsRed, indicating relative Population C activity per Population A. Error bars indicate s.d. of triplicates