Rifamycin R, a novel metabolite from a mutant of Nocardia mediterranea.

Rifamycin Z, a novel ansamycin from a mutant of Nocardia mediterranea.

Ansamycin biogenesis: studies on a novel rifamycin isolated from a mutant strain of Nocardia mediterranei.

A novel ansamycin, rifamycin W, was isolated from a mutant strain of Nocardia mediterranei. The metabolic origin of rifamycin W was studied by (13)C nuclear magnetic resonance spectroscopy. Examination of the proton-decoupled pulse and Fourier transform (13)C spectra of rifamycin W biogenetically enriched with [1-(13)C]-, [2-(13)C]-, and [3-(13)C]propionate and with [1-(13)C]acetate has reveale...

An Australian isolate of Nocardia mediterranea producing rifamycin SV.

Since its first announcement by P. Sensi et at. in 19591}, the rifamycin complex has been extensively studied by a number of workers2). The type culture Nocardia mediterranea (Margalith et Beretta) Thiemann et at. 1969*, then known as Streptomyces mediterranei^ was isolated from a soil sample collected in France. Sugawara et al.l) culturing an isolate (4107 A2) from a Japanese soil sample, repo...

Thiazorifamycins. III. Biosynthesis of rifamycins P, Q and verde, novel metabolites from a mutant of Nocardia mediterranea.

The thiazorifamycins are derived from rifamycin S and cysteine; rifamycins P and Verde are formed by chemical reactions, while rifamycin Q synthesis involves obligatory enzymatic assistance. All antibiotics come from a common six-member precursor lacking C-1 of cysteine; the thiazin-2-one ring of rifamycin Verde retains both C-2 and C-3 of cysteine, while the thiazole ring of rifamycins P and Q...

Rifamycin G, a further product of Nocardia mediterranei metabolism.

RIFAMYCIN G, A FURTHER PRODUCT OF NOCARDIA MEDITERRANEI METABOLISM GIANCARLO LANCINI and GIUSEPPE SARTORI Gruppo Lepetit S.p.A., Research Laboratories, 20158 Milano, Italy (Received for publication January 16, 1976) Several natural rifamycins have been isolated in addition to the products of Nocardia mediterranei fermentation originally described by SENSI and coworkers.1) These include rifamyci...