A set of 600 actinomycetes strains which were isolated from marine sediments from various sites in the Pacific and Atlantic Oceans were screened for the production of bioactive secondary metabolites. Marine streptomycete strains were found to be producers of well known chemically diverse antibiotics isolated from terrestrial streptomycetes, as in the case of marine Micromonospora strains. New marine members of the rare genus Verrucosispora seem to be a promising source for novel bioactive secondary metabolites as shown in the case of the abyssomicin producing strain AB-18-032.
A new bicyclic 19-peptide, BI-32169, has been isolated from the culture broth of Streptomyces sp. (DSM 14996). Its structure has been established by amino acid analysis, mass spectrometry, and 2D NMR analysis. BI-32169 consists exclusively of protein amino acids and is cyclized from the side chain of Asp(9) to the N-terminus of Gly(1). One disulfide bond between Cys(6) and Cys(19) forms a bicyclic structure. BI-32169 and its methyl ester derivative showed potent inhibitory activity against the human glucagon receptor (IC(50) 440 and 320 nM, respectively) in a functional cell-based assay.
The structure of the known secondary metabolite β‐rubromycin was corrected, based on spectroscopic and chemical investigations, from o‐quinone 1 to p‐quinone 6. By feeding [U‐13C3]malonic acid to the rubromycin‐producing strain, Streptomyces sp. A1, the polyketide origin of the skeleton was verified, but the identity of the starter unit and the folding mechanism of the polyketide chain are still unclear. From the culture broth of the strain A1, in addition to 6, the co‐metabolites γ‐rubromycin (3), δ‐rubromycin (4) and 3′‐hydroxy‐β‐rubromycin (7) were isolated. Their structures were determined or confirmed by detailed spectroscopic analysis. The rubromycins inhibit HIV‐1 reverse transcriptase (RT) and are cytostatically active against different tumor cell lines.
Five new piperidine alkaloids (1-5), named streptazones A, B(1), B(2), C, and D, were isolated from Streptomyces strains FORM5 and A1. Their structures were established on the basis of detailed MS and NMR analysis. Streptazone A (1) exhibited significant cytotoxic activity against selected human tumor cell lines.
Variation of the culture conditions of Streptomyces sp. strain A1, which produces streptazolin (1), resulted in the isolation of four new co-metabolites: 5-O-(beta-D-xylopyranosyl)streptazolin (3), 9-hydroxystreptazolin (4), 13-hydroxystreptazolin (5), and streptenol E (6). Their structures were established by spectroscopic and chemical methods. The possible biosynthetic relationship between the streptazolins and the streptenols is discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.