U-56,407, a new antibiotic related to asukamycin: isolation and characterization.

U-56,407, a bright yellow, crystalline antibiotic was isolated from fermentations of Streptomyces hagronensis (strain 360). This antibiotic was extracted from fermentation broths with halogenated hydrocarbons and purified by silica gel chromatography and crystallization. U-56,407 is active in vitro against Gram-positive bacteria but not Gram-negative organisms. It failed to demonstrate in vivo activity in experimentally infected mice. Physical-chemical characterization of U-56,407 supports a molecular formula of C29H32N2O7 and a structure related to the antibiotic asukamycin.