FIG 7.

(A) Growth kinetics of M. tuberculosis coaAKD strain. A growth kinetics study was performed to assess the time required to achieve a bactericidal effect in the absence of inducer P₁. The M. tuberculosis coaAKD strain was grown with 10 ng/ml of P₁ until an A₆₀₀ of ∼0.2 was reached. Harvested and washed cells were used to inoculate cultures supplemented with 0, 10, or 25 ng/ml of P₁. Culture growth was monitored by plating for survivors on plates containing P₁. The data are a representation of the results of two such experiments. (B) Effect of P₁ concentration on MtPanK expression in the M. tuberculosis coaAKD strain. Protein samples prepared from day 6 postexposure to P₁ of the growth kinetics study were used for Western blot analyses. Two micrograms of total protein from the lysates were loaded per lane, blotted, and probed with anti-MtPanK antibody (top panel) or MtSigA antibody (bottom panel). 0P₁, 10P₁, and 25P₁ represent the P₁ concentrations (in ng/ml) used in the growth kinetics study. Rv data represent a sample from the M. tuberculosis H37Rv control. Std data represent His₍₆₎-PanK in the top panel and His₍₆₎-SigA in the bottom panel. (C) In vivo phenotype of M. tuberculosis coaAKD strain. Mice were infected by the intravenous (i.v.) route with the M. tuberculosis H37Rv strain and M. tuberculosis coaAKD strain with 3 mice per time point. The course of infection was monitored over 150 days postinfection in the absence of P₁ supplementation. Bacterial loads in lungs and spleen were measured by plating organ homogenates for CFU on 7H10 plates for the control strain and 7H10 plates supplemented with 50 ng/ml of P₁ for the conditional-expression strain.