Streptomyces tenebrarius

Streptomyces tenebrarius). Gentamicin is isolated from Micromonospora purpurea, and it consists of a mixture of approximately equal amounts of three compounds gentamicines C[, C[j, and Cj. Amikacin and netilmicin are semisynthetic drugs. Amikacin is a chemical modification of kanamycin. Netilmicin is a semisynthetic derivative of schizomycin, which is isolated from Micromonospora inyoensis. 

It belongs to family nebramycins, is isolated from Streptomyces tenebrarius. Its antibacterial activity is similar to gentamicin and slightly more active than gentamicin against Pseudomonas aeruginosa and Proteus. 

Apramycin is a broad-spectrum aminocyclitol antibiotic and component of the nebramycin complex, produced by a strain of Streptomyces tenebrarius. Use of this antibiotic is specifically aimed at mass therapy of colibacillosis and salmonellosis in veal calves and swine. It is administered to calves by intramuscular or oral route at a dose of 20-40 mg/kg body weight/day for 5 days, and to swine via the drinking water at a dosage of 7.5-12.5 mg/kg bw/day for 7 days, or via the feed at a rate of 100 mg/kg feed for 28 days. It is further used for treatment of colibacillosis in lambs given orally at a dosage of 10 mg/kg bw/day for 3-5 days, and for treatment of E. coli septicemia in poultry administered in the drinking water at a concentration of 250-500 mg/L for 7 days. In contrast to other aminoglycosides, apramycin is not used in human medicine. 

Kharel MK, Basnet DB, Lee HC, Liou K, Woo JS, Kim BG, Sohng JK. Isolation and characterization of the tobramycin biosynthetic gene cluster from Streptomyces tenebrarius. FEMS Microbiol. Lett. 2004 230 185-190. 

Tobramycin is one component (factor 6) of a mixture produced by fermentation of Streptomyces tenebrarius. Lacking the C-3 hydroxyl group, it is not a substrate for APH(3 )-1 and APH(3 )-II and so has an intrinsically broader spectrum than kanamycin. It is a substrate, however, for adenylation at C-2 by ANT(2 ) and acetylation at C-3 by AAC(3)-I and AAC(3)-II and at C-2 by AAC(2 ) (Fig. 38.26). It is widely used parenterally for difficult infections, especially those by gentamicin-resistant Pseudomonas aeruginosa. It is believed by some clinicians to be less toxic than gentamicin. 

Nebramycins, closely related aminoglycosides produced by Streptomyces tenebrarius, have been separated on a neutral polystyrene-based column, with aqueous sodium hydroxide as eluant and... 

C18H36N4O10 468.503 Prod, by Streptomyces tenebrarius. Cryst. (MeOH). Sol. H2O fairly sol. MeOH poorly sol. butanol, hexane. 

Reviews have appeared on the synthesis of aminoglycoside antibiotics, and on the formation of new aminocyclitol antibiotics by mutants of amino-cyclitol-producing organisms fed with aminocyclohexanol or related subunits. The structures of eight minor components of the nebramycin complex elaborated by Streptomyces tenebrarius have been elucidated besides neamine and related pseudo-disaccharides, the new components are pseudo-trisaccharides related to kanamycin B, and the 3 -hydroxy analogue of the principal component of the complex, apramycin (see Vol. 10, p. 130). ... 

The biosynthesis of the aminoglycoside antibiotics has been reviewed. Apramycin, a broad-spectrum aminoglycoside antibiotic produced by a strain of Streptomyces tenebrarius, has been assigned the structure (361), which contains residues of 4-amino-4-deoxy-D-glucose and an octadiose that exists as a rigid bicyclic system. The structure (361), which was first derived from chemical and spectroscopic evidence, was confirmed by A"-ray crystallographic analysis. 

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