Cloning and heterologous expression of blasticidin S biosynthetic genes from Streptomyces griseochromogenes.

Two small chromosomal DNA fragments (2.6 and 4.8 kb) from the blasticidin S producer Streptomyces griseochromogenes were cloned in the high copy number vector pIJ702 and shown to confer increased resistance to blasticidin S upon S. lividans TK24. These fragments were used to screen a library of S. griseochromogenes DNA prepared in the cosmid shuttle vector pOJ446. Cosmids containing DNA inserts of at least 23 kb were identified which hybridized to one or the other resistance fragment, but not to both. Transformation of S. lividans TK24 with several cosmids hybridizing with the 4.8 kb resistance fragment resulted in clones that produced cytosylglucuronic acid, the first intermediate of the blasticidin S biosynthetic pathway, and other blasticidin-related metabolites. A strain of S. lividans TK24 harboring both the 4.8 kb-hybridizing cosmid and the 2.6 kb resistance fragment cloned in pIJ702 produced 12.5 times as much demethylblasticidin S as the transformant harboring the cosmid alone.

New cyanocyclines from a cyanide-treated broth of Streptomyces lusitanus.

Organic extracts of Streptomyces lusitanus, the producer of the anticancer antibiotic naphthyridinomycin [1], were found to contain two additional compounds active in an antibiotic screen. As with 1, these reacted with NaCN added at the end of the fermentation. One of the addition products has been named cyanocycline B [3] and is derived from N-desmethylnaphthyridinomycin [4], while the other has been named cyanocycline C [5], and is derived from the hydroquinone 6 of 1. Cyanocycline C is unstable and was characterized after conversion to the dimethyl derivative with CH2N2 in the presence of TFA. The implications of these metabolites for the biosynthesis of 1 are discussed. A third new antibiotic, cyanocycline D [8] was isolated from the cyanide-treated broth and proved to be an artifact in which the oxazolidine ring had been opened by cyanide. The potential relevance of the formation of 8 to the reaction of 1 with DNA is also discussed.

New products related to kinamycin from Streptomyces murayamaensis. I. Taxonomy, production, isolation and biological properties.

Six new products of Streptomyces murayamaensis sp. nov. Hata et Ohtani, the producer of the kinamycins, were isolated by silica gel column chromatography. The antibacterial activities of the new products, as well as that of dehydrorabelomycin and murayaquinone, previously isolated products of the same organism, were compared to the kinamycins. Three of the products had antibacterial activities similar to the kinamycins, while two others had activity only against Gram-positive bacteria. Dehydrorabelomycin and one other metabolite had no detectable antibacterial activity. The organism was found to be capable of aerial mycelium formation, with sporophores branched at regular intervals bearing square-ended spores with smooth surfaces. The culture contains L,L-diaminopimelic acid in the cell wall (Type I), is highly resistant to lysozyme, and lecithinase- and melanin-positive, suggesting a relationship with the genus Streptoverticillium and the lavendulae group of the genus Streptomyces.

Utilization by Saccharomyces cerevisiae of 5'-methylthioadenosine as a source of both purine and methionine.

Cells of the yeast Saccharomyces cerevisiae are normally impermeable to the purine nucleosides adenosine and 5'-deoxy-5'-methylthioadenosine (MTA), a product of polyamine biosynthesis. cordycepin-sensitive, adenosine-utilizing strains of S. cerevisiae were able to use MTA to fulfill an auxotrophic requirement for purine. Cordycepin-sensitive strains carrying a met5 mutation were also able to use MTA as a source of methionine. These MTA-utilizing strains of S. cerevisiae should be useful for metabolic studies of the fate of MTA.