Griseochromogenes

There are two commercial fungicides, the antibiotics blasticidin S and kasugamycin, that act via the inhibition of protein biosynthesis (Figure 4.19). Blasticidin S is a fermentation product obtained from cultures of Streptomyces griseochromogenes, and has specific activity in the control of P. oryzae, similar to kasugamycin, a secondary metabolite of S. kasugaensis. However, much of the earlier work on mode of action was carried out using another antibiotic, cycloheximide. 

Blasticidin S. Blasticidin S is the first successful agricultural antibiotic developed in Japan. It was isolated from the culture filtrates of Streptomyces griseochromogenes by Takeuchi et al. (7), and the potent curative effect of blasticidin S on rice blast was found by Misato et al. (8) Thereafter the benzyl-aminobenzene sulfonate of blasticidin S was reported to be least phytotoxic to the host plant without reducing antifungal activity against Pyricularia oryzae, the pathogen of rice blast (9), and... 

Six novel, cytosine nucleosides were isolated from the fermentation broth of S. griseochromogenes, which produces blasticidin S (55, see Scheme 22). The structural relationship between these nucleosides and cytosinine, the nucleoside moiety of blasticidin S, was investigated.87 One of these compounds was identified as l-(/3-D-glucopyrano-syluronic acid)cytosine (53). The presence of 53 was taken as evidence... 

Blasticidin S is an antibiotic of pyrimidine type, discovered in 19SS in the metabolites of Streptomyces griseochromogenes Fu i imgpetal., 1955). Blastiddin S, soluble in water, appears in the form of white needles. Its structure was eluddated by Yonehara and Otake (1966) S-[4-[3-amino-5-[(amino-imino-mcthyl)-methyl-amino]-1 -oxopentylj-amino]-1 -[4-amino-2-oxo-1 (2H)-pyrimidinyl]-1,2,3,4-tetrade-oxy- -D-er/7rohex-2-ene pyranuronic acid (9). 

Blasticidin S (327) is an antifungal agent used against rice blast disease in Japan. It was isolated in 1958 from Streptomyces griseochromogenes [411] and the structure and absolute stereochemistry were elucidated by chemical means [412-415] and confirmed by X-ray spectroscopy [416,417]. The biosynthesis has also been determined [418,419]. 

C15H24, Mr 204.36, oil, a sesquiterpene hydrocarbon of the triquinane type from cultures of Streptomyces griseochromogenes and S. UC 5319. It is the first isolable biosynthetic intermediate in the pathway from farnesyl pyrophosphate to the antibiotically active pentalenolactones. ... 

The final stages in the biosynthesis of the peptidyl-nucleoside antifungal agent blasticidin S, produced by Streptomyces griseochromogenes, have been eluci-... 

Blasticidins pyrimidine antibiotics synthesized by Streptomyces griseochromogenes (see Nucleoside antibiotics). They inhibit the growth of fungi, e.g. the rice fungus, Piricularia oryzae, and a few bacteria. The antibiotic effect is due to suppression of polypeptide chain elongation during protein biosynthesis. 

Blasticidin S Streptomyces griseochromogenes Cytosine 4-Deoxy-4-amino-2,3-hexen-uronic acid Cytidine, Aqrl-tRNA... 

Tautomycetin Immunosuppressive TauI/TmcR Streptomyces griseochromogenes C5 tautomycetin oxygenation [155,803]... 

Leucylblastieidin S, 8 (Table 1), had been reported to accumulate when fermentations of S. griseochromogenes were kept below pH 4.0. When washed cells were presented with 8, it disappeared and blasticidin S appeared in a time-dependent manner (16). However, it was subsequently shown that washed mycelia produced a measurable amount of 1, even without the addition of 8 (59). Although it is prc ble that 8 can be converted to 1, it may be the result of a nonspecific leucylaminopeptidase (80). 

CGA synthase is specific for UDP-glucuronic acid and for either cytosine or 5-aib-stituted cytosines neither uracil nor adenine were competent acceptors. The relative rates of cytosine derivatives as acceptors in the CGA synthase reaction are given in Tabic 7 (Guo J and Gould SJ, unpublished results). The suitability of 5-fluorocytosine, 10, as a substrate readily explains the production of 5-fluoroblasticidin S, 11, when 10 was fed to S. griseochromogenes (22). The formation of 5-hydroxyCGA from 5-hydroxycytosine (83,84) may be relevant to mildiomycin biosynthesis (85) (see Section HI.D). 

The detection of pentopyranone, 28, in cultures of S. griseocfiromogenes grown in the presence of arginine hydroxamate and cytosine provided a source for this apparent precursor to pentopyranines C and D. Pentopyranone was tested as an oxidoreductase substrate with cell-free extracts of S. griseochromogenes. NAD and NADP were each tested with this extract, but only the former was found to be a competent coenzyme, and... 

CnH28N806 440.458 Nucleoside antibiotic. Isol. from Strepto-myces griseochromogenes. Shows moderate antibiotic activity. Sol. H2O. 

C16H24N8O5 408.416 From Streptomyces griseochromogenes IF013413. Active against rice blast. Sol. 

C23H37N9O6 535.602 Prod, by Nocardioides albus and Strepto-myces griseochromogenes. Phytotoxin. Shows acaricidal, insecticidal and antiinflammatory props. Needles (H2O). Sol. H2O fairly sol. MeOH, DMSO poorly sol. CHCI3, hexane. 

C17H25FN8O5 440.433 Prod, by Streptomyces griseochromogenes IF013413 in presence of fluorocytosine. Antimicrobial agent. Powder. Sol. H2O poorly sol. butanol, hexane. 

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