New tylosin analogs produced by mutants of Streptomyces fradiae.

New macrolide antibiotics produced by mutants from Streptomyces fradiae NRRL 2702.

The mycarose-biosynthetic genes of Streptomyces fradiae, producer of tylosin.

The tylCK region of the Streptomyces fradiae genome was sequenced, revealing an incomplete set of five tylC genes encoding all-but-one of the enzymes involved in the biosynthesis of mycarose. The latter is a 6-deoxyhexose sugar required during production of the macrolide antibiotic, tylosin. The missing mycarose-biosynthetic gene, tylCVI, was found about 50 kb distant from its functional partne...

enhancement of tylosin production in streptomyces fradiae by mutation

in order to increase tylosin production by streptomyces fradiae, two mutagens, i. e. uv and ems (ethylmethanesulfonate) were used. death curves were plotted for these mutagens. optimum condition for obtaining mutants by uv radiation was determined by using a uv source lamp at a distance of 20 cm for 40-60 seconds. when ems was used at 4% (w/v) concentration, the best mutants were isolated after...

The tylosin producer, Streptomyces fradiae, contains a second valine dehydrogenase.

A second NAD-dependent valine dehydrogenase (VDH) of Streptomyces fradiae was detected and purified to homogeneity by affinity chromatography on Reactive-Blue 2 Sepharose followed by gel filtration and Mono Q fast protein liquid chromatography. The relative molecular masses of the native enzyme and its subunits were determined to be 80,000 and 41,000, respectively, indicating that the enzyme is...

Metabolic regulation in tylosin-producing Streptomyces fradiae: phosphate control of tylosin biosynthesis.

The effects of increased concentration of inorganic phosphate on the biosynthesis of tylosin, the level of the intracellular adenylates, the energy charge, and the activities of enzymes involved in the synthesis of tylonolide precursors were studied in Streptomyces fradiae NRRL 2702. No metabolic response was observed when elevated levels of inorganic phosphate were added in idiophase. Increase...