Table 2. Mce3R Regulon Is Required for Azasteroid 4a Activity^a.

^aThe data shown are representative of at least two independent biological replicates and were performed in technical triplicate.

^bWith cholesterol or glycerol as a carbon source, the indicated strain of Mtb in 7H9 medium was incubated with 20 μM 4a or DMSO control and INH at various concentrations (2-fold dilutions) for 14 days at 37 °C.

^cWith glycerol as a carbon source, the indicated species of mycobacteria in 7H9 medium was incubated with 20 μM 4a or DMSO control and INH or BDQ at various concentrations (2-fold dilutions) for 4–7 days at 37 °C.

^dThe drug concentration at which no growth occurred was recorded as the drug MIC. MIC values are shown in Table S1B. The ratio of the drug MIC in the presence of 4a to the MIC of INH or BDQ alone was determined. Ratios of 0.0625–0.125 are indicated with green shading and reflect potentiation. Ratios of >0.125 and ≤0.5 are indicated with orange shading and reflect low potentiation due to low activity of INH against M. marinum. Ratios >0.5 are indicated with red shading and reflect no change in MIC.