Polyene antifungal antibiotic produced by Streptomyces rimosus along with oxytetracycline, q.v. Recovered from fermentation broth by extracting the mycelium with butanol. Isoln and antifungal activity: Davisson et al., Antibiot. Chemother. 1, 289 (1951); Seneca et al., ibid. 2, 435 (1952); Davisson et al., US 2963401 (1960 to Pfizer). Partial structure: Cope et al., J. Am. Chem. Soc. 87, 5452 (1965). Structure: L. Falkowski et al., J. Antibiot. 29, 197 (1976); R. Pandey, K. L. Rinehart, ibid. 30, 146 (1977).