Mycobacterium tuberculosis H37Rv and M. smegmatis were grown at 37°c in 7H9 media supplemented with 10% ADC (Becton Dickinson), 0.2% glycerol and 0.05% Tween 80. For log phase, cells were grown to OD 540 0.2. Roller bottles were used for culturing M. tuberculosis, and shaker flasks for M. smegmatis.