FIG 3.

Expression of low levels of mycobactin and carboxymycobactin by the M. tuberculosis ΔhupB mutant strain and their restoration to normal levels upon hupB complementation. M. tuberculosis H37Rv, M. tuberculosis ΔhupB mutant, and M. tuberculosis ΔhupB/pMS101 strains were grown in high (HI, 8 μg Fe ml⁻¹)- and low (LI, 0.02 μg Fe ml⁻¹)-iron media. (A and B) Carboxymycobactin and mycobactin expressed by these organisms harvested after 14 days of growth. (C and D) The time course expression of the two siderophores by M. tuberculosis H37Rv and the mutant strain studied until day 18. The vertical bars represent the standard deviations of the means from three identical experiments.