CFUs of mixes of strains in CAA and BSA at 0 and 48 hours

Population sizes of each of the strains (wildtype WT, lasB mutants DLB and lasR mutants DLR) were quantified in monoculture and in coculture at different ratios of WT to mutant (9:1, 1:1 or 1:9). Experiments were conducted in two growth media: CAA (casamino acids + M9), which all strains could take up and BSA (casamino acids + M9 + BSA, which could only be digested using elastase). To distinguish the strains in cocultures, fluorescently-labelled strains (YFP or DsRed) were used and mixed in all possible combinations to test for labelling effects. We quantified population sizes by plating out dilution series and counting colony-forming units. These are listed in the file for t=0h and t=48h. This shows how the ratio of the strains and the total population size change throughout the experiment. These data were used to generate Fig. 1B, 2B and 3.