Bioactive benzopyrone derivatives from new recombinant fusant of marine Streptomyces.

In our searching program for bioactive secondary metabolites from marine Streptomycetes, three microbial benzopyrone derivatives (1-3), 7-methylcoumarin (1) and two flavonoides, rhamnazin (2) and cirsimaritin (3), were obtained during the working up of the ethyl acetate fraction of a marine Streptomyces fusant obtained from protoplast fusion between Streptomyces strains Merv 1996 and Merv 7409. The structures of the three compounds (1-3) were established by nuclear magnetic resonance, mass, UV spectra, and by comparison with literature data. Marine Streptomyces strains were identified based on their phenotypic and chemotypic characteristics as two different bioactive strains of the genus Streptomyces. We described here the fermentation, isolation, as well as the biological activity of these bioactive compounds. The isolated compounds (1-3) are reported here as microbial products for the first time.

The Electrospray Ionization - Mass Spectra of Erythromycin A Obtained from a Marine Streptomyces sp. Mutant.

In our ongoing search for production improvements of bioactive secondary metabolites from marine Streptomyces through the induction of mutations using UV light, out of 145 isolates, mutant 10/14 was able to produce potent antibacterial metabolites other than the parent strain as established by chromatographic analysis. Up-scaling fermentation of mutant 10/14, followed by working up and isolation delivered five metabolites, phenazine, 1-acetyl-beta -carboline, perlolyrin and erythromycin A, along with an oily substance. The latter two compounds were responsible for the antibacterial activity of the strain. In this article, we discuss with the mutation of the marine Streptomyces sp. AH2, bioactivity evaluation, fermentation and isolation of the microbial metabolites. Moreover, we study to first time in detail the 1D and 2D NMR and ESI MS data including ESI MS(2) and MS(3) patterns combined with HRESI MS of erythromycin A.