Figure 2.

Screening of Tn-insertion mutant strains, derived from the (p)ppGpp⁰ strain, which recovered viability under antibiotic treatment. A, Tn-insertion mutants, derived from the (p)ppGpp⁰ mutant, that survived in the presence of a lethal concentration of tetracycline (50 μg/ml) were selected. Tetracycline was treated three times every 4 h to the entire recruited culture. B, a genetic map of the acnB gene (VC0604) in V. cholerae. Arrowheads indicate the positions of Tn insertions. C–H, bacterial viability of acnB-deletion mutants under tetracycline (C and F), erythromycin (D and G), and chloramphenicol (E and H) treatments. Aliquots of each culture were resuspended in several concentrations of antibiotic-containing LB broth, sampled at 4 h post-inoculation, and serially diluted for cfu counting.