Figure 4. Complementation of ΔMSDGC-1 with MtbDGC and its long term survival.

(A) ΔMSDGC-1 a strain of M. smegmatis was complemented with MtbDGC and its growth was compared with wildtype as well as ΔMSDGC-1. Cultures were grown in MB7H9 medium with 0.02% v/v glucose and 0.05% Tween-80 as carbon source. Aliquots were withdrawn at different time interval after culture reached stationary phase (48 hours of growth) and plated on MB7H9 agar supplemented with Kanamycin containing 2% w/v glucose as carbon source. The colony forming unit were determined and plotted. (B) Level of MtbDGC increases in stationary phase. ΔMSDGC-1 was transformed with MtbDGC and expression was studied in three phases of growth i.e. exponential, early stationary and late stationary phase. The α subunit (RpoA) of RNA polymerase was used as an control because its level remains unchanged in different phases of growth. Whole cell lysates was separated on 10% SDS-PAGE and analyzed by Western blot technique probed with antibody raised against MtbDGC.