Figure 3. . Expression of the Mycobacterium tuberculosis rpf genes rpfA–E upon resuscitation from nutrient starvation, as measured by RT-qPCR.

(A) Expression of rpf genes of Mtb strains grown to OD_{600 nm}= 0.2 after resuscitation in 7H9 broth relative to that of corresponding NS cultures; (B) Expression of rpf genes of Mtb strains grown to OD_600nm = 0.4 after resuscitation in 7H9 broth relative to that of corresponding NS culture.

RNA was purified from Mtb strains following 11 days of nutrient starvation and after resuscitation in supplemented 7H9 broth at two time points (OD_{600 nm} = 0.2 and OD_{600 nm} = 0.4), and RT-qPCR was performed after cDNA synthesis. After normalization to sigA, ΔΔC_T was calculated using the difference in C_T value (ΔC_T) of each rpf gene upon resuscitation relative to that during nutrient starvation. The fold change in rpf gene expression in the rpoB mutant and the control strains was calculated by 2∧-ΔΔC_T.

*p < 0.05; **p < 0.05; ***p < 0.001. C_T: Cycle threshold; OD: Optical density.