Figure 2.

Induction of individual lysogens following irradiation with 20 J/m². (A) Snapshots of cells harboring the pR-GFP (top panels) and pR′-tR′-GFP (bottom panels) reporter plasmids undergoing induction taken at the times shown after irradiation. Some cells lyse and disappear from the field of view. Cell silhouettes were determined from dark-field microscopy images. (B) Fluorescence profiles of pR-GFP (blue) and pR′-tR′-GFP (red) of individual cells including those viewed in the top and bottom panels in (A), respectively, as a function of time. The sharp drop in every profile is due to lysis. (C) pR (blue) and pR′-tR′ (red) promoter activity profiles of individual cells derived from the fluorescence data in (B) as a function of time.