NOVEL BIOACTIVE OXAZOLOMYCIN ISOMERS PRODUCED BY STREPTOMYCES-ALBUS-JA3453

Two novel oxazolomycin isomers, oxazolomycins B (2) and C (3), were is olated from the fermentation broth of an oxazolomycin-producing strain , Streptomyces albus JA3453. Both compounds are geometrical isomers of oxazolomycin (1), the configurations of their triene moieties being ( 4'E, 6'E, 8'E) (2) and (4'Z, 6'E, 8'E) (3) while that of oxazolomycin fl) is (4'Z, 6'Z, 8'E), Compounds 2 and 3 exhibited potent inhibitory activity against crown gall formation with the same MIC (0.8 mu g/disk ) as oxazolomycin. Compounds 2 and 3 showed no antibacterial activity against Agrobacterium tumefaciens, in contrast to oxazolomycin which h as specific anti-A. tumefaciens activity.