FIG 1.

M. avium subsp. paratuberculosis in vitro “dependence” on mycobactin. (A) ⁵⁵FeCl₃ uptake assay in MAP-cattle (MAPc), MAP-sheep (MAPs), and several other M. avium subspecies. (B) ⁵⁵FeCl₃ uptake assay in MAP-cattle in the presence or absence of exogenous mycobactin J. *, P < 0.05; **, P < 0.01; ***, P < 0.001. (C) MAP-cattle growth assay in the presence or absence of exogenous mycobactin J on 7H10 agar. Tenfold serial dilutions of wild-type M. avium subsp. paratuberculosis K10 grown in 7H9 without mycobactin J supplementation were spotted onto 7H10 with or without mycobactin J. The plates were incubated at 37°C for 6 weeks and then photographed.