Figure 3.

Effect of stress stimuli on M. tuberculosis ppa promoter activity. BCG harbouring pJIN6 (gfp controlled by ppa promoter; hatched bars) or pJIN10 (gfp controlled by sigE promoter; white bars) were grown for 24 hours in 7H9 medium of pH 4.5 or containing either 50 mM 2,2'-dipyridyl, 500 mM NaCl or 5 mM H₂O₂. The fold change in fluorescence represents the fluorescence value of bacteria after 24 hour exposure to stress conditions divided by the fluorescence level of the same bacteria grown in the absence of stress stimuli.