Thomas H. Stoudt

Studies on the biosynthesis of cholesterol. VII. Formation of cholesterol precursors by yeast

Abstract The nonsaponifiable material from resting yeast which had been incubated with C14-carboxyl-labeled sodium acetate gives with digitonin a radioactive sterol fraction with a higher count than the purified ergosterol-C14 which can be isolated from the crude sterols by repeated crystallization and acetylation. A zymosterol-C14 fraction was also obtained from the sterols and had a higher count than the ergosterol-C14. From the mother liquors of the digitonides, squalene-C14 was separated in the pentane fraction of a chromatogram on alumina. The eluates obtained with benzene, ether, and methanol were fed like the squalene-C14 to rats. Squalene and the benzene and ether fractions gave cholesterol-C14.

Hydroxylation of progesterone by Bacillus cereus and Bacillus megaterium.

Abstract The introduction of an 11α-hydroxy group into progesterone by two species of Bacillus cereus and of a 15β-hydroxy group into progesterone by Bacillus megaterium has been demonstrated.

Isolation of diosgenin by microbiological hydrolysis of saponin.

Abstract By microbial hydrolysis the saponins in pulverized Dioscorea tuber have been cleaved into the component parts, diosgenin and the sugar moieties. In one case a derivative, Δ 4 -diosgenone, was isolated. Although a wide range of conditions may be used in this conversion, the simplest include a mixed culture fermentation of pulverized fresh or dry tuber slurry aerated by stirring for 3–6 days at room temperature and maintained near pH 4. The yields are comparable to those obtained by acid hydrolysis. Only fungi were found to effect this conversion.

Antigenic subunit of the polypeptide antigenic complex of the Melvin strain of Neisseria gonorrhoeae

Abstract An antigenic subunit of molecular weight 66,000 daltons has been isolated from the antigenic complex of the Melvin strain of Neisseria gonorrhoeae . Incubation of the complex in 8M urea at room temperature for four hours resulted in the dissociation of the subunit from the complex. It was separated from the complex by chromatography of the incubation mixture on a Sepharose 6B column in 50 mM ammonium bicarbonate pH 8.5 without 8M urea and further purified by affinity chromatography. This communication reports on a newly isolated antigenic protein devoid of LPS present in the bacteria.