Figure 3.
β-Galactosidase assay in liquid media. (A) M. smegmatis MS82 was pre-grown in Middlebrook 7H9 containing 50 ng/ml ATc, and diluted into fresh media containing different ATc concentrations. Every 24 h and for 3 days, one aliquot of each culture was used to measure β-galactosidase activity and one aliquot was diluted into fresh medium containing the same amount of ATc as before. Black bars: 24 h; gray bar: 48 h; white bars: 72 h. (B) TB38.2 was pre-grown in Middlebrook 7H9 containing 200 ng/ml ATc, and diluted into fresh media containing different ATc concentrations. Every 48 h and for 6 days, one aliquot of each culture was used to measure β-galactosidase activity and one aliquot was diluted into fresh medium containing the same amount of ATc as before. Black bars: 48 h; grey bar: 96 h; white bars: 144 h. Values are indicated as percentages of maximal activity.