FIG 4.

Dose dependent transcriptional activities of iron reporter M. bovis BCG strains treated with (A) “actives” SA23 and SA72 as well as (B) “inactives” SA33 and SA34. Three independent biological replicates were carried out for each experiment. Trends were consistent across these determinations. Representative results from one biological replicate (from two technical replicates) are shown. The data shown are mean values with the SDs depicted as error bars. Dots and bars have the same meanings as in Fig. 3. Panel A shows that the “actives” SA23 and SA72 neither induced nor suppressed the iron regulator gene (ideR) in either medium but induced the iron acquisition gene mbtB (iron-depleted minimal medium > iron-supplemented minimal medium) and suppressed the iron storage gene bfrB (iron-supplemented minimal medium > iron-depleted minimal medium). Panel B shows that the “inactives” SA33 and SA34 did not affect the transcriptional activities of ideR, mbtB, or bfrB in either medium. The recombinant strains retained dose-dependent viabilities in both media.