FIG. 1.

The five TA systems are not involved in the growth inhibition mediated by amino acid starvation and do not advantage poststress recovery. Individual cultures of the wild-type (WT) (square) and Δ5 (triangle) strains (A and B) and mixed cultures of the wild-type strain and the nalidixic acid-resistant derivative of the Δ5 strain (Δ5 Nal^r) (circle) (C and D) were challenged with SHT (2.5 mg/ml) (see Materials and Methods). The viability of treated (open symbols) and untreated (filled symbols) cells was measured for 120 min upon SHT addition (A and C). After 120 min of starvation, SHT was removed and the viability of individual (B) and mixed (D) cultures was measured for 180 min (until early stationary phase). For each graph, the number of CFU/ml at each time point (tx) was normalized to that at time zero (t₀). The graphs represent the averages from three (A and B) and two (C and D) independent experiments. Similar results were obtained in experiments in which the wild-type Nal^r strain was mixed with the Δ5 strain (data not shown).