Figure 4.

Schematic illustration of dual selection of genetic circuits. (A) OFF→ON selection. A mixture of E. coli JW1226 harboring selector plasmid pCI-hsvtk and Plasmid-B, -C, or -D was plated on an ‘OFF selection plate’ containing AHL. The colonies were pooled and re-plated on an ‘ON selection plate’ without AHL. (B) ON→OFF selection. The same cell mixture was first grown on ON selection plates in the absence of AHL, followed by growth on an OFF selection plate containing AHL. The bar graphs represent the abundance ratios of Plasmid-B, -C and -D found in the media taken from each selection step.