Isolation and purification of canadaphore, a siderophore produced by Helminthosporium carbonum

A new siderophore was isolated and purified from the spent growth medium of the fungus Helminthosporium carbonum by solvent extraction and reverse phase high pressure liquid chromatography. This new molecule has been assigned the name Canadaphore. Canadaphore was detected in culture filtrates after 15 days of growth and production was maximal after growth of H. carbonum to maximal stationary phase in modified Fries basal medium. Production of Canadaphore was completely suppressed when the organism was grown in medium supplemented with iron. Mass spectral analysis yielded a molecular mass of 680 Daltons for the iron-Canadaphore complex and 627 Daltons for the iron-free molecule. Spectroscopic analysis indicates that Canadaphore is a siderophore of the hydroxamate type.