FIG. 3.

Use of the RExBAD approach to study the essential cell division gene ftsL. Overnight cultures of E. coli TG1 and TG1catRExBADftsL grown in LB medium supplemented with 0.2% arabinose were washed in LB medium twice and diluted 1:100 into LB medium or LB medium supplemented with 0.2% glucose or with 0.2% arabinose, and then they were grown at 37°C for 6 h. Optical light microscopy images were captured with a ×40 objective. (Top panels) E. coli TG1. (Bottom panels) E. coli TG1catRExBADftsL. Cell filamentation was observed 4 h after subculturing in LB medium or LB medium supplemented with glucose for strain TG1catRExBADftsL but not for strain TG1. Filamentation led to cell death and lysis after 6 h in LB medium or LB medium supplemented with glucose.