Three new studies have wide implications for cholesterol homeostasis, identifying a novel mechanism by which a sterol-sensing domain functions in the regulated activation of sterol regulatory element binding proteins.

The first total synthesis of ergosta-5,8-dien-3β-ol, an uncommon sterol previously isolated from an alga and several microorganisms, has been developed. For the first time, a full set of spectroscopic data of this sterol is presented.

GOTTLIEB, D., R. J. KNAUS, and S. G. WOOD. 1978. Differences in the Sterol synthesizing pathways of sterol-producing and non-sterol-producing fungi. Phytopathology 68: I 168-1169. The mycelia of several sterol-producing and non-sterolsqualene was detected in the non-sterol-producing fungi. The producing fungi were analyzed for the presence of squalene, block in the synthesis of ergosterol by th...

To study exogenous sterol metabolism during the suppression or stimulation of cholesterol biosynthesis induced by treatments for hyperlipidemia, we determined plasma plant sterol concentrations before and after administration of an HMG-CoA reductase inhibitor, pravastatin, and compared these with changes in these plasma sterol levels by the bile-sequestrating resin, cholestyramine. The effects ...

Sterols and sphingolipids are limited to eukaryotic cells, and their interaction has been proposed to favor formation of lipid microdomains. Although there is abundant biophysical evidence demonstrating their interaction in simple systems, convincing evidence is lacking to show that they function together in cells. Using lipid analysis by mass spectrometry and a genetic approach on mutants in s...

precursors, including lanosterol, into poriferasterol (III) by Ochromonas malhamensis has been demonstrated (Hall et al., 1969; Lenton et al., 1971). Since a cell-free extract of peas can alkylate lanosterol, cycloartenol or desmosterol but not 24,25-dihydrolanosterol (I) or cholesterol (11), it has been suggested that sterols without a A24-bond cannot be alkylated (Russell et al., 1967). Howev...

OBJECTIVE Hypercholesterolemia is a major risk factor for coronary artery disease. Therapeutic lifestyle changes include dietary modifications such as inclusion of phytosterols, which effectively lowers low-density lipoprotein (LDL) cholesterol in margarines and other fats. Their effectiveness in nonfat moieties is not yet established. The aim of this study was to examine if phytosterols alter ...

Sterol 14alpha-demethylase encoded by CYP51 is a mixed-function oxidase involved in sterol synthesis in eukaryotic organisms. Completion of the Mycobacterium tuberculosis genome project revealed that a protein having homology to mammalian 14alpha-demethylases might be present in this bacterium. Using genomic DNA from mycobacterial strain H(37)Rv, we have established unambiguously that the CYP51...

In flowering plants, the developing embryo consists of growing populations of cells whose fates are determined in a position-dependent manner to form the adult organism. Mutations in the FACKEL (FK) gene affect body organization of the Arabidopsis seedling. We report that FK is required for cell division and expansion and is involved in proper organization of the embryo. We isolated FK by posit...

OBJECTIVE Macrophage expression of both apolipoprotein E (apoE) and ABCA1 have been shown to modulate lipid efflux from these cells and to play an important atheroprotective role in vivo. We evaluated the relationship between apoE and ABCA1 for regulating cellular sterol efflux. METHODS AND RESULTS ApoE-mediated, but ABCA1-independent, lipid efflux was demonstrated in 3 model systems. First, ...