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16-Deethylindanomycin (A83094A) is a novel pyrrole-ether antibiotic produced by a strain of Streptomyces setonii. The antibiotic, which is structurally similar to indanomycin (X-14547A), is active in vitro against Gram-positive bacteria as well as coccidia. During the process of screening actinomycetes for novel antimicrobial substances, a new strain of Streptomyces setonii, isolated from a sample of soil collected in the state of Montana, U.S.A., was found to produce a new antibiotic. The active compound, which remained associated with the producing biomass, was isolated and found to be structurally similar to the pyrrole-ether X-14547A (indanomycin)1'25. This paper describes the taxonomyand fermentation studies on the producing organism as well as the isolation and characterization of A83094A(the structure shown in Fig. 1).

A new memberof the spiroketal-containing macrolide class of fermentation-derived natural products was isolated from mycelial extracts of Streptomyces diastatochromogenes. The principal component, A82548A,was shown to possess a 22-memberedmacrolide ring system onto which wasincorporated both a spiroketal and a hemiketal moiety. Relative stereochemistry was established by single crystal X-ray diffraction studies. Absolute stereochemistry was determined via hydrolysis of the amino sugar glycosidically linked to the aglycone, which was identified as L-kedarosamine. The overall three-dimensional structure is closely related to that of the macrolides cytovaricin, rutamycin, and ossamycin.

A novel group of antibiotics, comprising microbiologically-active structurallyrelated factors A25822A, B, D, H, L, M and N, produced by culturing Geotrichum flavo-brunneum NRRL 3862 under submerged aerobic fermentation conditions was isolated by extraction. The individual factors were separated and purified by chromatography and crystallization. The major factor, A25822B, a 15-aza-24-methylene-D-homocholestadiene is a white crystalline compound, C28H45NO. The antibiotics are highly active against fungi and marginally active against bacteria.A mixture of broad spectrum antifungal antibiotics was detected in the crude fermentation broth of the fungi Geotrichum flavo-brunneum NRRL 3862. The novel antibiotic complex was isolated by extraction of the whole fermentation broth or mycelium, and the structurallyrelated factors A25822A1), B, D, H, L, M and N were separated and purified by chromatographic techniques and fractional crystallization. The complex, consisting of one major and six minor components, was highly active against a broad spectrum of pathogenic fungi, including Candida species and Trichophyton species.A25822B, biologically the most active component, was inhibitory in a range of <0.0312 -5.0 mcg/ml. The complex was also active against several gram-positive and gram-negative bacteria". IsolationGeotrichum flavo-brunneum was grown under submerged aerobic fermentation conditions on a casein corn steep agar medium for 7 days. Approximately 10 °o of the antibiotic synthesized was released into the fermentation broth while the remaining 90 % was retained by the cells2).The fermentation broth was filtered and the active principles extracted from the cells by multiple methanol extractions. The extracts were combined, concentrated to an aqueous phase and extracted with ethyl acetate at pH 10. The ethyl acetate extract was concentrated to an oily residue. The crude antibiotic complex was a brown, viscous oil which was soluble in most organic solvents, insoluble in water, and stable in solutions over a pH range of at least pH 3 to pH 10, at room temperature. The crude oil was dissolved in diethyl ether and the active compounds extracted with 0.2 N sulfuric acid solutions. The active components were re-extracted from the aqueous phase at pH 10 with n-hexane and ethyl acetate. A25822B, the most abundant of the factors, was recovered from the n-hexane extract by