Figure 1.
Effects of (p)ppGpp on viability of V. cholerae strains against clinically used antibiotics. A, detection of (p)ppGpp accumulation pattern in wildtype N16961 by TLC. Wildtype N16961 was divided into two groups and grown in LB supplemented with or without SHX in the presence of [32P]orthophosphate for 2 h. Cellular extracts were prepared and analyzed in TLC. ΔrelAΔspoT, (p)ppGpp0, and ΔdksA mutants were also grown with [32P]orthophosphate and processed for the TLC assay. B–J, bacterial viabilities under various clinically used antibiotics were measured in each growth condition. Wildtype N16961 and various (p)ppGpp-associated mutant strains were inoculated in LB and aerobically grown to each growth stage. Aliquots of each culture were resuspended in several concentrations of antibiotic-containing LB broth, sampled at 4 h post-inoculation, and 10-fold serially diluted to assess the number of cfu.