ABSTRACT
Chloroform extracts of M. leprae suspensions--crude, partially purified and purified--were prepared by standard methods. Similar extracts were also prepared from the livers of normal armadillos using the same methods that were used to prepare crude and partially purified M. leprae suspensions. The only chloroform extract that supported the growth of M. paratuberculosis was the one prepared from Percoll gradient-purified M. leprae. Other four extracts not only did not support the growth of mycobactin-dependent M. paratuberculosis, but also inhibited the growth of mycobactin-independent strain of M. paratuberculosis. These results suggest the presence of mycobactin-like substance in M. leprae, and also, the presence of other unknown substance(s) in the crude suspensions of armadillo livers that inhibits the growth of M. paratuberculosis.