scholarly journals Synthesis of non-hydroxy-galactosylceramides and galactosyldiglycerides by hydroxy-ceramide galactosyltransferase

1996 ◽  
Vol 317 (2) ◽  
pp. 589-597 ◽  
Author(s):  
Petra van der BIJL ◽  
Ger J. STROUS ◽  
Matthijs LOPES-CARDOZO ◽  
Jane THOMAS-OATES ◽  
Gerrit van MEER
Keyword(s):  
Fatty Acids ◽  
Endoplasmic Reticulum ◽  
Fatty Acid ◽  
Hydroxy Fatty Acid ◽  
Fast Atom Bombardment ◽  
Chinese Hamster ◽  
Mass Spectrometric ◽  
Collision Induced Dissociation ◽  
Spectrometric Analysis ◽  
Transfected Cells

Galactosylceramide (GalCer) is the major glycolipid in brain. In order to characterize the activity of brain UDPgalactose: ceramide galactosyltransferase (CGalT), it has been stably expressed in CGalT-negative Chinese hamster ovary (CHO) cells. After fractionation of transfected cells, CHO-CGT, on sucrose gradients, the activity resides at the density of endoplasmic reticulum and not of Golgi. A lipid chromatogram from CHO-CGT cells revealed two new iodine-staining spots identified as GalCer, since they comigrate with GalCer standards, can be metabolically labelled with [3H]galactose, are recognized by anti-GalCer antibodies, and are resistant to alkaline hydrolysis. A third [3H]galactose lipid was identified as galactosyldiglyceride. In the homogenate CGalT displays a 25-fold preference for hydroxy fatty acid-containing ceramides. Remarkably, endogenous GalCer of transfected cells contains exclusively non-hydroxy fatty acids: fast atom bombardment and collision-induced dissociation mass spectrometric analysis revealed mainly C16:0 in the lower GalCer band on TLC and mainly C22:0 and C24:0 in the upper band. Our results suggest that CGalT galactosylates both hydroxy- and non-hydroxy fatty acid-containing ceramides and diglycerides, depending on their local availability. Thus, CGalT alone may be responsible for the synthesis of hydroxy- and non-hydroxy-GalCer, and galactosyldiglyceride in myelin.

scholarly journals Improved Method for Gas Chromatographic–Mass Spectrometric Analysis of 1-13C-labeled Long-Chain Fatty Acids in Plasma Samples

2002 ◽  
Vol 48 (6) ◽  
pp. 906-912 ◽  
Author(s):  
José M Hernández-Pérez ◽  
Eduard Cabré ◽  
Lourdes Fluvià ◽  
Ágata Motos ◽  
Cruz Pastor ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Fatty Acid ◽  
Isotopic Ratio ◽  
Internal Standard ◽  
Mass Spectrometric ◽  
Spectrometric Analysis ◽  
Calibration Curves ◽  
Long Chain ◽  
Chromatographic Mass

Abstract Background: Gas chromatographic–mass spectrometric (GC/MS) tracking of stable-isotope-labeled substrates is useful in metabolic studies. However, GC/MS analysis of long-chain fatty acid methyl esters yields results that mostly depend on their concentration in the system. We describe a protocol aimed to obviate this and other drawbacks in plasma [1-13C]palmitic and [1-13C]oleic acid measurements. Methods: Lipoproteins were separated by sequential ultracentrifugation. Free or esterified heptadecanoic acid was used as internal standard. Fatty acids were derivatized to trimethylsilyl (TMS) esters. GC separation was in isothermal mode at 210 °C for 27 min. For both TMS-palmitate and TMS-oleate, M and [M + 1] signals were simultaneously acquired with a dual acquisition program in single-ion monitoring mode. Calibration mixtures containing increasing amounts of labeled fatty acids were prepared gravimetrically to construct calibration curves for isotopic enrichment. Likewise, five calibration curves (for increasing concentrations) were constructed for each fatty acid; this allowed selection of the most appropriate curve for the concentration in a plasma sample. Results: Oleic acid-TMS ester was clearly separated from that of its stereoisomer, elaidic acid. Within a 10-fold concentration range, the isotopic ratio was independent on the amount of the analyte in the sample, with a maximum uncertainty of 0.34% in terms of molar percent excess. In addition, the within- and between-day imprecision (CV) of the method was <1%. Conclusion: Results obtained with this method are independent of concentration and sufficiently precise for tracking 1-13C-labeled palmitic and oleic acids in biological samples

scholarly journals Endoplasmic Reticulum-Located PDAT1-2 from Castor Bean Enhances Hydroxy Fatty Acid Accumulation in Transgenic Plants

2011 ◽  
Vol 52 (6) ◽  
pp. 983-993 ◽  
Author(s):  
Hyun Uk Kim ◽  
Kyeong-Ryeol Lee ◽  
Young Sam Go ◽  
Jin Hee Jung ◽  
Mi-Chung Suh ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Fatty Acid ◽  
Transgenic Plants ◽  
Castor Bean ◽  
Hydroxy Fatty Acid ◽  
Fatty Acid Accumulation ◽  
Acid Accumulation

scholarly journals Lipid metabolism. Evidence of a δ-oxidation pathway for saturated fatty acids

1969 ◽  
Vol 111 (4) ◽  
pp. 395-399 ◽  
Author(s):  
P. S. Dimick ◽  
N. J. Walker ◽  
Stuart Patton
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Hydroxy Fatty Acid ◽  
Saturated Fatty Acids ◽  
Radioactive Tracer ◽  
Hydroxy Fatty Acids ◽  
Lactating Goats ◽  
Total Milk ◽  
Milk Lipids ◽  
Active Intermediates

1. Specific radioactivities of milk triglyceride fatty acids and γ- and δ-hydroxy fatty acids were measured after the intramammary infusion of [1−14C]acetate, δ-hydroxy[1−14C]laurate and [1−14C]laurate as their sodium salts into fed lactating goats. 2. Net incorporations of the radioactive tracer into the total milk lipids were comparable, being 16, 17 and 21% of the label infused respectively. 3. The specific radioactivities of the C4–C8 fatty acids after [1−14C]acetate infusion were lower than those of the C10–C14 fatty acids. 4. After δ-hydroxy[1−14C]laurate administration the milk triglyceride fatty acids were labelled and their specific radioactivities were characterized by decreasing values with increasing chain length of the fatty acids, implicating C4 unit incorporation. 5. The γ- and δ-hydroxy fatty acids isolated after [1−14C]laurate infusion were highly labelled and the milk triglyceride fatty acids, other than laurate, exhibited a labelling pattern similar to that of the fatty acids derived from the radioactive δ-hydroxy fatty acid. 6. Evidence is presented for the existence of saturated fatty acid δ-oxidation in the mammary gland, in which the γ- and δ-hydroxy fatty acids are active intermediates.

scholarly journals The role of lipid components of the diet in the regulation of the fatty acid composition of the rat liver endoplasmic reticulum and lipid peroxidation

1978 ◽  
Vol 174 (2) ◽  
pp. 585-593 ◽  
Author(s):  
Catherine T. Hammer ◽  
Eric D. Wills
Keyword(s):  
Lipid Peroxidation ◽  
Fatty Acids ◽  
Endoplasmic Reticulum ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acids ◽  
Acid Composition ◽  
Corn Oil ◽  
Lipid Peroxide

The fatty acid compositions of the lipids and the lipid peroxide concentrations and rates of lipid peroxidation were determined in suspensions of liver endoplasmic reticulum isolated from rats fed on synthetic diets in which the fatty acid composition had been varied but the remaining constituents (protein, carbohydrate, vitamins and minerals) kept constant. Stock diet and synthetic diets containing no fat, 10% corn oil, herring oil, coconut oil or lard were used. The fatty acid composition of the liver endoplasmic reticulum lipid was markedly dependent on the fatty acid composition of the dietary lipid. Feeding a herring-oil diet caused incorporation of 8.7% eicosapentaenoic acid (C20:5) and 17% docosahexaenoic acid (C22:6), but only 5.1% linoleic acid (C18:2) and 6.4% arachidonic acid (C20:4), feeding a corn-oil diet caused incorporation of 25.1% C18:2, 17.8% C20:4 and 2.5% C22:6 fatty acids, and feeding a lard diet caused incorporation of 10.3% C18:2, 13.5% C20:4 and 4.3% C22:6 fatty acids into the liver endoplasmic-reticulum lipids. Phenobarbitone injection (100mg/kg) decreased the incorporation of C20:4 and C22:6 fatty acids into the liver endoplasmic reticulum of rats fed on a lard, corn-oil or herring-oil diet. Microsomal lipid peroxide concentrations and rates of peroxidation in the presence of ascorbate depended on the nature and quantity of the polyunsaturated fatty acids in the diet. The lipid peroxide content was 1.82±0.30nmol of malonaldehyde/mg of protein and the rate of peroxidation was 0.60±0.08nmol of malonaldehyde/min per mg of protein after feeding a fat-free diet, and the values were increased to 20.80nmol of malonaldehyde/mg of protein and 3.73nmol of malonaldehyde/min per mg of protein after feeding a 10% herring-oil diet in which polyunsaturated fatty acids formed 24% of the total fatty acids. Addition of α-tocopherol to the diets (120mg/kg of diet) caused a very large decrease in the lipid peroxide concentration and rate of lipid peroxidation in the endoplasmic reticulum, but addition of the synthetic anti-oxidant 2,6-di-t-butyl-4-methylphenol to the diet (100mg/kg of diet) was ineffective. Treatment of the animals with phenobarbitone (1mg/ml of drinking water) caused a sharp fall in the rate of lipid peroxidation. It is concluded that the polyunsaturated fatty acid composition of the diet regulates the fatty acid composition of the liver endoplasmic reticulum, and this in turn is an important factor controlling the rate and extent of lipid peroxidation in vitro and possibly in vivo.

Gas chromatographic/mass spectrometric analysis of fatty acids found in aquatic algae

1988 ◽  
Vol 16 (1-12) ◽  
pp. 477-480 ◽  
Author(s):  
M. Cojocaru ◽  
M. Shlosberg ◽  
Z. Dubinsky ◽  
A. Finkel
Keyword(s):  
Fatty Acids ◽  
Mass Spectrometric ◽  
Mass Spectrometric Analysis ◽  
Spectrometric Analysis ◽  
Chromatographic Mass
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