ISOLATION, PROPERTIES AND TAXONOMIC RELEVANCE OF LIPID-SOLUBLE, IRON-BINDING COMPOUNDS (NOCOBACTINS) FROM NOCARDIA

Representative strains of the genus Nocardia, when grown on Fe-deficient media, produce intracellular lipid-soluble, Fe-binding compounds known as nocobactins. Strains representing the rhodochrous taxon fail to form such compounds. The formation of the nocobactins is completely repressed in bacteria grown on Fe-sufficient media. Procedures for purifying the nocobactins are described. From their various properties UV and visible spectra of the ferri- and desferri-materials, mobility upon TLC, and dissociation patterns in HCl), they can be distinguished from the mycobactins (related compounds from mycobacteria) and divided into 3 main classes. The classes correspond to the 3 well-described species of the genus Nocardia: N. asteroides, N. brasiliensis and N. caviae. The correlation of the nocobactin data with previous results of conventional numerical taxonomy is high. Two strains of N. asteroides did not produce nocobactins of the group type.