Fig. 3.

Decay of luciferase activity over time after removal of ComS* from the growth medium. The SPH130 strain was grown either in the presence of 2 μM ComS* (circles) or in the absence of ComS* (triangles). Bacterial growth is indicated by open symbols, whereas luminescence is indicated by filled symbols. After shifting the cells at time zero from a medium containing 2 μM ComS* to a ComS*-free medium, it took about 70 min before the luciferase activity started to decline (▴). In the parallel culture grown in the presence of ComS*, the luciferase activity started to decline as the culture approached stationary phase (●).