title: Identification of the free and conjugated sterol in a non-photosynthetic diatom,Nitzschia alba, as 24-methylene cholesterol.
abstract: Previous studies on the sterol fraction of the nonphotosynthetic marine diatom,Nitszchia alba, indicated the major sterol to be either brassicasterol (24R-methylcholesta-5,22-dien-3β-ol) or 22-dehydrocampesterol (24S-methylcholesta-5,22-dien-3β-ol) on the basis only of gas chromatographymass spectral analysis. The present studies using nuclear magnetic resonance, infrared, and gas chromatography-mass spectrometry on the free and bound sterol fractions isolated by preparative thin layer chromatography showed the presence in both fractions of a single sterol, with spectral and chromatographic properties identical with those reported for 24-methylenecholesterol (ergosta-5,24(28)-dien-3β-ol). This sterol may be the precursor of 24-methyl sterols found in diatoms. The bound sterol fraction was found to consist of a single compound identified as 24-methylenecholesterol sulfate. No sterol esters or sterol glycosides were detected.
authors: Department of Biochemistry, University of Ottawa, K1N 6N5, Ottawa, Canada.
authors: M
authors: M
authors: Kates
authors: Department of Biochemistry, University of Ottawa, K1N 6N5, Ottawa, Canada.
authors: P
authors: P
authors: Tremblay
authors: Department of Biochemistry, University of Ottawa, K1N 6N5, Ottawa, Canada.
authors: R
authors: R
authors: Anderson
authors: Scripps Institution of Oceanography, University of California, San Diego, 92093, La Jolla, California.
authors: B E
authors: BE
authors: Volcani