Figure 2. Nanocompartments protect Mtb from oxidative stress in acidic environments.

(A) OD₆₀₀ measurements of wild-type and DyP::Tn Mtb grown in 7H9 medium following exposure to H₂O₂ for 96 hr. Values reported are normalized to the untreated controls. CFU enumeration of wild-type and Mtb nanocompartment mutants grown in (B) standard 7H9 medium (pH 6.5) and (C–F) acidified 7H9 medium (pH 4.5) following exposure to oxidative stress (2.5 mM H₂O₂) for 72 hr. (G) Fluorescence emissions of wild-type and Δoperon Mtb expressing mrx1-roGFP exposed to 5 mM H₂O₂ at pH 4.5 in 7H9 medium for 60 min. Data are reported as a ratio of fluorescence emissions following excitation at 490 nm and 390 nm. Figures are representative of at least two (E, F) or three (A–D, G) independent experiments. p-Values were determined using unpaired t-test. *p<0.05, **p<0.01.