General structure of the ferrichromes, prototypical hy- droxamate type siderophores. All Penicillia that have been investi- gated, and many other fungal species, synthesize this type of sid- erophore. Several bacterial species, including E. coli, maintain a transport system for utilization of ferrichrome as an iron source. For ferrichrome, R 5 R9 5 R0 5 H; R- 5 CH3. Ferrichrome biosynthesis in the basidiomycetous fungus Ustilago maydis is initiated by gene sid 1, the product of which bears sequence homology to the lysine- N6-hydroxylase of E. coli (43).