Terpen-derivate aus Senecio-arten

Investigation of about 50 Senecio species has afforded many new substances, in addition to known compounds. Present in these plants are 23 fura     

Crystallization and preliminary X-ray investigation of a sarcoplasmic calcium-binding protein from amphioxus

Crystals of a sarcoplasmic Ca(2+)-binding protein from the protochordate amphioxus have been grown from solutions of ammonium sulfate. The crystals are orthorhombic, space group C222(1), with unit cell axes a = 59.6(1) A, b = 81.3(1) A and c = 82.4(1) A. There is one molecule in the asymmetric unit. The crystals diffract beyond 2.5 A and show less than 20% decline in diffraction intensities after a three day exposure to X-rays from a laboratory rotating anode source.     

Purification, crystallization and preliminary crystallographic analysis of porcine aldose reductase

Large crystals of porcine aldose reductase have been grown from polyethylene glycol solutions. The crystals are triclinic, space-group P1, with a = 81.3 A, b = 85.9 A, c = 56.6 A, alpha = 102.3 degrees, beta = 103.3 degrees and gamma = 79.0 degrees. The crystals grow within ten days to dimensions of 0.6 mm x 0.4 mm x 0.2 mm and diffract to at least 2.5 A. There are four molecules in the unit cell related by a set of three mutually perpendicular non-crystallographic 2-fold axes.     

Metabolism of very low density lipoproteins--effect of sardine oil.

The effect of feeding fish oil on the metabolism of lipoproteins was studied in rats. Rats were fed diet containing 10% sardine or groundnut oil for 6 weeks. There was a significant decrease in the total cholesterol, phospholipids and triglycerides as well as the amount of the lipids associated with VLDL and LDL in serum in fish oil-fed rats. The synthesis and secretion of lipoproteins particularly apoB containing lipoproteins by primary cultures of hepatocytes from these rats were studied by 14(C)-acetate or 3(H)-leucine labelling. Primary cultures of hepatocytes derived from sardine oil-fed rats showed reduced incorporation of 3(H)-leucine into apoB containing lipoproteins secreted into the medium when compared to those fed groundnut oil, indicating a decreased synthesis and secretion of apoB. This was further confirmed by significantly lower incorporation of 14(C)-radioactivity into total and individual lipids of VLDL secreted into the medium, as well as that associated with different lipids in cell layer. The activity of lipoprotein lipase in adipose tissue and aorta was significantly higher in rats fed sardine oil which may cause an increased clearance of triglyceride-rich lipoproteins from circulation. These results indicate that the fish oil exerts hypolipidemic effect particularly by decreasing the synthesis and secretion of VLDL by liver and possibly by an increased clearance of triglyceride-rich lipoproteins from circulation.     

Glycerol-induced unraveling of the tight helical conformation of Escherichia coli type 1 fimbriae.

Glycerol was found to unravel the helical conformation of Escherichia coli type 1 fimbriae without appreciable depolymerization. The linearized fimbrial polymers have a diameter of 2 nm, react strongly with a monoclonal antibody directed at an inaccessible epitope on native fimbriae, and display greater mannose-binding activity and trypsin sensitivity than native fimbriae. Removal of glycerol by dialysis results in spontaneous reassembly of the linear polymers into structures morphologically, antigenically, and functionally indistinguishable from native fimbriae.     

Evidence for autophosphorylation of hyaluronate binding protein and its enhanced phosphorylation in rat histiocytoma.

This report documents for the first time the in vitro autophosphorylation of purified 68 kDa hyaluronate binding protein in presence of [32P] ATP. The rate of phosphorylation is proportional to the concentration of protein and to the time of incubation up to 5 min. By both phosphoamino acid and western blot analysis with antiphosphotyrosine antibodies, we have confirmed that the phosphorylation occurs at tyrosine residues. Immunoprecipitation with anti HA binding protein antibody shows a 5 fold increase in the phosphorylation in macrophage histiocytoma compared to normal macrophage. Supplementing hyaluronate with hyaluronate binding protein in the medium is further shown to enhance total protein phosphorylation in rat histiocytoma.     

Deuterium NMR investigation of polymorphism in stratum corneum lipids

The intercellular lipid lamellae of stratum corneum constitute the major barrier to percutaneous penetration. Deuterium magnetic resonance and freeze-fracture electron microscopic investigation of hydrated lipid mixtures consisting of ceramides, cholesterol, palmitic acid and cholesteryl sulfate and approximating the stratum corneum intercellular lipid composition, revealed thermally induced polymorphism. The transition temperature of bilayer to hexagonal transition decreased as the ratio of cholesterol to ceramides in these mixtures was lowered. Lipid mixtures in which the stratum corneum ceramides were replaced by synthetic dipalmitoylphosphatidylcholine did not show any polymorphism throughout the temperature range used in the present study. The ability of the ceramide-containing samples to form hexagonal structures establishes a plausible mechanism for the assembly of the stratum corneum intercellular lamellae during the final stages of epidermal differentiation. Also, the bilayer to hexagonal phase transition of these nonpolar lipid mixtures could be used to enhance the penetration of drugs through skin.