Two antibiotics isolated from a culture MA-2465 were identified as aureothin and labilomycin, the chemical structures of which had been reported previously. It was also concluded that mycolutein and pulvomycin isolated as antibiotics in 1955 and 1957 respectively are also identical with aureothin and labilomycin. A cursory study of MA-2465 indicates that it is distinctly different from the cult...