CR dye fluorescence characterization of synthetic curli systems in the PQN4 lab strain (red) and the probiotic Nissle-derived PBP5 strain (green). We assessed 3 inducible curli fiber-producing plasmids, inducing transcription of the csgBACEFG operon by (a) arabinose, (b) IPTG, or (c) ATC. Cells harboring these curli plasmid systems, and controls without plasmids, were assessed after overnight incubation in LB medium with CR dye at a range of inducer concentrations. In each case, each data point shows the mean of 3 separate experiments.