FIG 2.

Growth of M. tuberculosis H37Rv, M. tuberculosis ΔhupB mutant, and M. tuberculosis ΔhupB/pMS101 strains in high- and low-iron media. The three strains were grown under high-iron (HI; 8 μg Fe ml⁻¹) and low-iron (LI; 0.02 μg Fe ml⁻¹) conditions in Proskauer and Beck medium. Growth was monitored by measuring the absorbance at 600 nm over a period of 21 days. The experiment was repeated thrice, and the figure represents data from one experiment. The double-headed arrow (↔) represents the lag phase seen in the growth of the mutant strain.