FIGURE 3.

RpoB mutation H526D is associated with altered cell wall permeability and resistance to cell wall stress following nutrient starvation. Intracellular accumulation of ethidium bromide 2 μg/ml (A) and Nile red 0.125 μM (B) by the 14-day-nutrient-starved Mtb RpoB H526D mutant and its parental strain were measured by fluorescence spectroscopy. The values at each time point are normalized to the baseline fluorescence value and to bacterial density. RFI, relative fluorescence intensity. (C) Susceptibility of 14-day-nutrient-starved RpoB H526D mutant and parental strain to incubation with 0.05% sodium dodecyl sulfate (SDS) for 6 h. Percent survival represents the number of surviving bacteria after challenge divided by the number of bacteria prior to incubation. ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001.