Colicin release in LB and M9-glucose. Representative microscopy images and induction-lysis curves of cells growing in LB (A,C) and M9-glucose (B,D) expressing E2crimson under control of the colicin E2 promoter (shown in red) and having constitutive yfp expression (green). Panel (C) shows induction-lysis curves of three cells labeled in image t1 of (A). E2crimson first rises, 2–3 hours after induction cells show a sharp drop in fluorescence indicating a lysis event. A faint red signal shows the remainder of the cell body after lysis. E2crimson time-traces in M9-glucose (D) of the cells labelled in (B) show that induced cells do not lyse and remain intact for periods longer than 12 hours.