Microbial growth promotion studies of exochelin MN and analogues thereof.

The ability of exochelin MN and three synthetic analogues to promote the growth of various strains of mycobacteria and Gram-negative bacteria was investigated. The results indicated that growth promotion ability of these compounds depends either on ligand exchange with mycobactin or on the exochelin permease. Despite stronger iron complexing capacity, the structural analogues showed weaker growth promotion ability than exochelin MN, which further supported our hypothesis of pH-dependent iron(III)-release of exochelin MN.