bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence for diplasmalogen as the major component of rabbit sperm phosphatidylethanolamine
Authors: Touchstone Joseph C. , Alvarez Juan G. , Levin Sidney S. , Storey Bayard T. 
Published: November 2006

AbstractThe question of whether diplasmalogens [1,2‐di(O‐1′‐alkenyl) phosphatidyl derivatives] make up part of the plasmalogen component of cell phospholipids was examined using rabbit epididymal spermatozoa. These cells are readily obtained as a highly homogeneous suspension and long have been known to have high plasmalogen content. Phospholipids were determined by thin layer chromatography (TLC) with CuSO4 staining. Plasmalogens were determined by hydrolysis of the phospholipids with TCA/HCl, followed by TLC and CuSO4 staining. Ethanolamine derivatives were determined by ninhydrin. The phosphatidylethanolamine (PE) content of these cells was 29±2 μg/108 cells, 90% of which was assayed as diplasmalogen and 10% as diacyl PE. No monoplasmalogen could be detected. The presence of diplasmalogen as the major component of PE was given further support from infrared and proton nuclear magnetic resonance (1H‐NMR) spectroscopy, which showed the presence of O‐1′‐alkenyl substituents but near absence of O‐acyl substituents. The phosphatidylcholine (PC) content of the cells was 104±5 μ/108 cells, of which 50% was monoplasmalogen with the 1′‐alkenyl group on the 2 position of the glycerol moiety. No diplasmalogen was found in PC. The other phospholipids in rabbit sperm were phosphatidylglycerol (PG), cardiolipin (CL), sphingomyelin (SP) and lysophosphatidylcholine (LPC). Phosphatidylserine (PS) and phosphatidylinositol (PI) were present at the limits of detectability of the TLC method. None of these phospholipids contained plasmalogen. The PE component of rabbit sperm phospholipids appears to differ from that of the other cells in having the previously unreported diplasmalogen as its major constituent.
Purification of the human anionic polypeptide fraction of the apo‐bile lipoprotein complex by zonal ultracentrifugation
Authors: Martigne M. , Domingo N. , Lafont H. , Nalbone G. , Hauton J. C. 
Published: November 2006

AbstractThe two main proteic constituents of the human Apo‐bile lipoprotein complex (BLC), i.e., the anionic polypeptide fraction (APF) and the IgA fragments, were separated by preparative zonal ultracentrifugation using a sucrose gradient containing 1.5 mM glycodesoxycholate. The purification of the APF was verified by sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis and immunology, and its amino acid composition then was determined. This procedure was used to obtain a polyclonal antiserum directed solely against the APF.
Effect of very long chain fatty acids on peroxisomal β‐oxidation in primary rat hepatocyte cultures
Authors: Christiansen Erling N. , Gray Tim J. B. , Lake Brian G. 
Published: November 2006

AbstractPrevious studies have demonstrated that certain high fat diets can induce peroxisomal fatty acid β‐oxidation in rodent liver and that this may be due to their content oftrans 22∶1 fatty acids. In this study we have examined the effects ofcis andtrans 22∶1 fatty acids (erucic and brassidic) and oleic acid (18∶1) on palmitoyl‐CoA oxidation, carnitine acetyltransferase and carnitine palmitoyltransferase activities in primary rat hepatocyte cultures. Brassidic and erucic acid and, to a lesser extent, oleic acid were cytotoxic to rat hepatocytes. However, at a concentration of 0.1 mM, brassidic acid produced small increases in palmitoyl‐CoA oxidation and carnitine acetyltransferase activities in hepatocytes cultured 70 hr. Treatment of cells with 0.1 and 0.3 mM of either erucic or oleic acid had no effect on any of the enzymes measured.
Effect of dietary cholesterol protected against ruminal hydrogenation on the plasma cholesterol and liver of sheep
Authors: Ashes J. R. , Cook L. J. , Sidhu G. S. 
Published: November 2006

AbstractDietary supplements containing cholesterol or sunflower oil were prepared to protect them against degradation in the rumen. On feeding daily supplements containing 1–2 g protected cholesterol and/or 100g protected sunflower oil to sheep, along with a basal ration of crushed oat grain and lucerne chaff, a rise in the plasma cholesterol was observed when compared with control animals. Livers from sheep fed protected cholesterol were enlarged, friable and cirrhotic in appearance and contained large deposits of esterified and free cholesterol, while livers from animals fed protected sunflower oil alone contained much less cholesterol. Octadecenoates constituted the major fatty acids in cholesterol esters, which, in animals fed protected sunflower oil, were mainly polyunsaturated. The factors involved in the deposition of liver lipid at very low dietary cholesterol concentrations (0.11–22%) in sheep compared with monogastric animals are discussed.
Influence of acute injection of chloroquine on the biliary secretion of lipids and lysosomal enzyme on rats
Authors: Lafont H. , Chanussot F. , Dupuy C. , Lechene P. , Lairon D. , Charbonnier‐Augeire M. , Chabert C. , Portugal H. , Pauli A. M. , Hauton J. C. 
Published: November 2006

AbstractPhospholipids and cholesterol combine with a protein fraction (IgA and an acid polypeptide) in bile to form the bile lipoprotein complex.We wished to determine whether lysosomes participated only in IgA secretion or if their secretory role also involved the lipid components of the bile complex. This aspect was studied with a single acute injection of chloroquine, a lysosomotropic drug. The results show that a nonnegligible quantity of IgA travels through the lysosomes. In addition, phospholipid and cholesterol levels undergo a significant (P<0.05) decrease 1 hr after injection before increasing to normal levels. In contrast to the total inhibition of protein secretion (β‐glucuronidase, acid phosphatase), a transitory decrease of the secretion of bile lipids takes place that suggest secretory mechanisms involving organelles other than lysosomes.
The composition of cardiac phospholipids in rats fed different lipid supplements
Authors: Charnock J. S. , Abeywardena M. Y. , McMurchie E. J. , Russell G. R. 
Published: November 2006

AbstractChanges in dietary lipid intake are known to alter the fatty acid composition of cardiac muscle of various animals. Because changes in cardiac muscle membrane structure and function may be involved in the pathogenesis of arrythmia and ischemia, we have examined the effects of dietary lipid supplements on the phospholipid distribution and fatty acid composition of rat atria and ventricle following 20 weeks feeding of diets supplemented with either 12% sunflower‐seed oil or sheep fat.Neither lipid supplement produced significant changes in the proportions of cholesterol, total phospholipids or phosphatidylcholine, phosphatidylethanolamine or diphosphatidylglycerol,—the phospholipid classes that together account for more than 90% of the total phospholipids of rat cardiac muscle. Significant changes were found in the profiles of the unsaturated fatty acids of all 3 phospholipid components of both atria and ventricle. Although similar, the changes between these tissues were not identical. However, in general, feeding a linoleic acid‐rich sunflower seed oil supplement resulted in an increase in the ω‐6 family of fatty acids, whereas feeding the relatively linoleic acid‐poor sheep fat supplement decreased the level of ω‐6 fatty acids but increased the levels of the ω‐3 family, resulting in major shifts in the proportions of these families of acids. In particular, the ratio of arachidonic acid: docosahexaenoic acid (20∶4, ω‐6/22∶6, ω‐3), which is higher in all phospholipids of atria than ventricle, is increased by feeding linoleic acid, primarily by increasing the level of arachidonic acid in the muscle membranes. As dosahexaenoic acid does not occur in the diet, the increase in this acid which occurs after feeding animal fat, presumably arises from increased conversion of the small amounts of linolenic acid in all diets when the amount of linoleic acid present is reduced.
Lipid composition and protoplast‐forming capicity ofStreptomyces antibioticus
Authors: Zuñeda M. C. , Guillenea J. J. , Dominguez J. B. , Prado A. , Goñi F. M. 
Published: November 2006

AbstractThe lipid and fatty acid composition of a strain ofStreptomyces antibioticus has been studied as a function of culture age and glycine concentration in the growth medium. Under all conditions, the main polar lipids were phosphatidylethanolamine, cardiolipin and phosphomannoinositides in order of decreasing abundance; no ornithinolipids were detected. Acylglucoses and menaquinones were found among the nonpolar lipids. The main fatty acids present were anteiso 15∶0 and anteiso 17∶0. The lipid composition of the cells varied with the age of the culture, but no uniform pattern of variation was found in the cultures grown on different amounts of glycine. Among the cells harvested at the end of the exponential phase of growth, those grown on 2% glycine give the highest yield of protoplast formation. These cells were found to contain low amounts of nonpolar lipids and of phosphatidylethanolamine, and high proportions of anteiso fatty acids. We propose that the membrane bilayer of these cells, because of its peculiar lipid composition, is particularly stable and fluid. As a consequence, the yield and stability of derived protoplasts should be increased.
Steroids from aquatic organisms: V. Main sterols of the fresh water snail,Biomphalaria tenagophila
Authors: Seldes Alicia M. , Gros Eduardo G. 
Published: November 2006

AbstractThe free sterols of the snail,Biomphalaria tenagophila, were isolated and characterized by means of gas chromatography and gas chromatography‐mass spectrometry techniques. The mixture contains the common steroids found in freshwater molluscs, principally cholesterol. The presence of cholesta‐5,7‐dien‐3β‐ol is without precedent in freshwater organisms. The occurrence of 7‐oxo‐cholesterol in freshwater snails, but not bivalves, from the same freshwater source, would indicate a difference in the physiology of such snails and bivalves.
Brown adipose tissue triacylglycerol fatty acids of obese and lean mice: In situ and in transplants
Authors: Roberts Jennifer L. , Ashwell Margaret , Enser Michael 
Published: November 2006

AbstractThe triacylglcyerols of white adipose tissue (WAT) from animals with high rates of lipogenesis, such as obese hyperglycemic mice or hypothalamically lesioned rats, contain high proportions of palmitoleic acid (16∶1) and low proportions of linoleic acid (18∶2). These differences appear to result from dilution of dietary 18∶2 by synthesized fatty acids, particularly 16∶1. To test this we have investigated the triacylglycerol fatty acid composition of brown and white adipose tissue of lean and obese mice, as brown adipose tissue (BAT) has a higher lipogenic rate than WAT and lipogenesis is faster in obese than in lean mice. Between three and eight weeks of age the proportions of fatty acids in the tissues changed, with a marked fall in milk‐derived lauric and myristic acids. From 8 to 16 weeks they were more stable and the proportions of 16∶1 and 18∶2 in the different tissues were as expected, with the highest and lowest proportions, respectively, in BAT from obese mice. When BAT from obese mice was transplanted under the kidney capsule of lean mice, or vice versa, for one month, the fatty acid composition of the grafts changed toward that of the host BAT. The proportions of 18∶2 and, to a lesser extent, 16∶1 were slightly higher in the grafts than in the hosts but since this also occurred in lean‐to‐lean and obese‐to‐obese grafts it was probably a transplantation artifact. Overall, the results confirm than the physiological environment, rather than the source of the adipose tissue, is the major determinant of its fatty acid composition.
Desaturation and chain elongation of essential fatty acids in isolated liver cells from rat and rainbow trout
Authors: Hagve Tor‐Arne , Christophersen Bjørn O. , Dannevig Birgit H. 
Published: November 2006

AbstractIsolated hepatocytes from rainbow trout and rat were incubated with14C‐labeled linoleic acid, linolenic acid, dihomogammalinolenic acid or eicosapentaenoic acid. The most striking difference in the desaturase activity was the lower level of Δ5 desaturase in trout than in rat. No Δ4 desaturation of 22∶4(n−6) to 22∶5(n−6) was observed in either of the two species, while the conversion of 22∶5(n−3) to 22∶6(n−3) was significant in both groups and highest in rainbow trout. The chain‐elongating activity was remarkably similar in the two species, except for the “dead‐end” elongation which was distinctly more important in fish.
Properties of diacylglycerol kinase purified from bovine brain
Authors: Lin C‐H. , Bishop H. , Strickland K. P. 
Published: November 2006

AbstractA nearly homogeneous but somewhat unstable diacylglycerol kinase (ca. MW 72,000 daltons) was purified from bovine brain by modification of the procedure of Kanoh et al. (Kanoh, H., Kondoh, H., and Ono, T. [1983]J. Biol. Chem. 258, 1767–1774). The purification consisted of four steps (brain cytosol isolation and successive chromatography on DEAE‐cellulose, Sephadex G‐25 for desalting and ATP‐agarose) carried out in buffers stabilized with EDTA, ATP and dithiothreitol (DTT). Specific activities, determined within 4 hr of purification, ranged from 908–1857 nmol ATP incorporated/min/mg protein, with the variation reflecting the instability. Optimal activities required deoxycholate (0.1%), one of the phosphoglycerides [phosphatidylcholine (PC), phosphatidylethanolamine (PE) or phosphatidylserine (PS)] (0.025–0.25 mM), ATP (5 mM, apparent Km=0.57 mM), 1,2‐dioleoyl‐rac‐glycerol (5 mM, apparent Km=1 mM) and Mg2+ (10 mM, apparent Km=2.2 mM). Phosphatidylinositol (PI) was slightly less effective than PC, PE or PS and noninhibitory in combination with PC, PE or PS. Relative to PC phosphatidic acid (PA) (52%), sphingomyelin (48%), lyso‐PC (1.5%) and lyso‐PI (28.6%) were less effective activators. The sulfhydryl reagents,p‐chloromercuribenzoic acid (PCMB) (1.0 mM),N‐ethylmaleimide (NEM) (1.0 and 2.0 mM) and 5,5′‐dithiobis‐(2‐nitrobenzoic acid) (DTNB) (1.0 mM), showed strong inhibition of activity which was prevented by 0.5 mM DTT. In contrast to other reports, this purified enzyme showed no monoacylglycerol kinase activity. Comparison of diacylglycerols of varying fatty acid composition indicated that the enzyme showed a preference for substrates with at least one unsaturated fatty acid, particularly in the 2‐position. With saturated fatty acids the order of preference was C10 and C12>C14>C16>C18. Such a pattern indicates that the enzyme shows little selectivity that favors the generation of particular molecular species of PA.
Dexamethasone blocks arachidonate biosynthesis in isolated hepatocytes and cultured hepatoma cells
Authors: Marra Carlos A. , de Alaniz Maria J. T. , Brenner Rodolfo R. 
Published: November 2006

AbstractThe effect of dexamethasone on the incorporation and conversion of [1‐14C]eicosa‐8,11,14‐trienoic acid to arachidonic acid in isolated hepatocytes and in hepatoma tissue culture (HTC) cells was studied. In both kinds of cells, no changes in the exogenous acid incorporation were found when the hormone was added to the incubation media at 0.1 or 0.2 mM concentration, while the biosynthesis of arachidonic acid was significantly depressed. The effect on the biosynthesis was faster in isolated normal liver cells (60 min) than in tumoral cells (120 min) and reached an inhibition of ca. 50% after 3 hr of treatment. The addition of cycloheximide (10−6 M) also caused a marked decrease in the biosynthesis of this polyun‐saturated fatty acid, but when dexamethasone was added to the media simultaneously with cycloheximide, a synergistic action was not observed. The results obtained show that protein synthesis would be involved in the modulation of the biosynthesis of arachidonic acid by glucocorticoids. The changes in the Δ5 desaturation of labeled 20∶3ω6 to arachidonic acid correlated with changes in the fatty acid composition in isolated cells.
Effects of pre‐ and postweaning undernutrition on polyphosphoinositide pools in rat kidney
Authors: Ananth Uma S. , Ramakrishnan C. V. , Hauser George 
Published: November 2006

AbstractThe effects of undernutrition on polyphosphoinositide levels in rat kidneys removed and frozen immediately after animal death or 10 min later were determined. Weanling (21‐day‐old) rats of dams fed a 5 or 22% protein diet and litters fed either normal or protein‐deficient diets for an additional six wk were used. Nutritional deprivation lowered phosphatidylinositol‐4‐phosphate (PtdIns4P) preferentially (35–40%) but but preserved phosphatidylinositol‐4,5‐bisphosphate (PtdIns4,5P2) at weaning. This effect was not completely reversed in animals nutritionally rehabilitated after weaning. Postweaning protein deficiency did not reduce the levels of these lipids. Postmortem loss was the same for all five groups, minimal for PtdIns4P and about one‐third for PtdIns4,5P2.
Practical liquid chromatographic separation of the phenols in technical cashew nutshell liquid fromAnacardium occidentale
Authors: Sood Suresh K. , Tyman John H. P. , Durrani Aziz , Johnson Robert A. 
Published: November 2006

AbstractThe practical separation of cardanol from technical cashew nutshell liquid or its distillate has been effected by liquid chromatography on Silica Gel H 60 (TLC type) with solute/absorbent in the range 1∶5–1∶6. Concentrates of the monoene, diene and triene constituents of cardanol have been prepared by argentation liquid chromatography on Silica Gel H 60 with dry incorporation of 15% silver nitrate. The present use of pressurized columns was made prior to the advent of flash chromatography.
Simultaneous analysis of low plasma levels of deuterium‐labeled saturated and unsaturated fatty acids ast‐butyldimethylsilyl esters
Authors: Parsons H. , Emken E. M. , Marai L. , Kuksis A. 
Published: November 2006

AbstractA sensitive and accurate method for detection and quantitation of deuterated fatty acids in the presence of large amounts of unlabeled fatty acids is described using mass fragmentography in combination with the preparation of tertiarybutyldimethylsilyl esters (t‐BDMS). The method has been applied to determination of deuterated stearic, oleic, elaidic and linoleic acids in human plasma lipoproteins following duodenal perfusion with a micellar mixture of acids. Over a concentration range of 10–1000 ng/ml, the average coefficient of variation for the linoleate was 3% and for the oleate (elaidate) ester was 2%.
The hydrolysis of very low density lipoproteins and chylomicrons of intestinal origin by lipoprotein lipase in ruminants
Authors: Christie William W. , Noble Raymond C. , Clegg Roger A. 
Published: November 2006

AbstractThe hydrolysis by lipoprotein lipase of a very low density lipoprotein/chylomicron fraction, obtained from the intestinal lymph of sheep, has been studied in vitro. Rapid hydrolysis of triacylglycerols, with an accumulation of free fatty acids, was observed. After an initial lag period, phosphatidylcholine also was hydrolyzed. No specificity for particular fatty acids in the triacylglycerols (or phosphatidylcholines) was observed.
A specific detector for nitrogen and halogen compounds in TLC on coated quartz rods
Authors: Patterson P. L. 
Published: November 2006

AbstractA new detector has been developed for use with the Iatroscan TH‐10 TLC/FID instrument‐a “solid‐phase” chromatographic system (SPC). This new detection system contains a unique stage of detection that is called a flame thermionic ionization detector or FTID. The FTID evolved from a similar device that recently has been used in gas chromatography. The basic concept of an FTID is that organic sample compounds are first decomposed by combustion in an H2‐air flame. The FTID does not sense any of the ionization produced directly in the flame but, instead, re‐ionizes the combustion products by means of a unique thermionic transducer placed in the downstream effluent of the flame. The thermionic transducer ionizes specifically only those combustion products which are acidic or electronegative in chemical activity. In particular, organic samples containing nitrogen (N) or halogen atoms combust to products which are especially well detected with high sensitivity. Hence, the FTID adds to the Iatroscan a state‐of‐the‐art detection stage which produces large signals for nitrogen and halogen compounds and negligible signals for hydrocarbon compounds.
Improved sample application methods for the Iatroscan
Authors: Read H. 
Published: November 2006

AbstractA new method of sample application has been developed for Chromarods to give improved interrod and interrun repeatability. A rotary method using a small rig has been constructed to hold and rotate the rod as the sample is applied. Improved interrod repeatability of 0.5–0.7% standard deviation compared to 1.3–3.3% standard deviation using the Iatroscan recommended method has been achieved.
Calibration of the Iatroscan‐Chromarod system for marine lipid class analyses
Authors: Parrish C. C. , Ackman R. G. 
Published: November 2006

AbstractA two‐step development procedure with partial scanning after the first development resolves seawater lipids into seven classes. The low concentration in seawater of some of these classes necessitates calibration close to the detection limit of the flame ionization detector (FID). From 0.2 to 5.0 μg the FID response usually is curvilinear, necessitating multilevel calibration. Interrod precision was poor for most of this range, and this prompted an investigation of factors affecting FID responses.Peak areas were found to depend on the distribution of lipid material on the Chromarod. Also investigated were the effects of temperature, humidity, acid cleaning and double developments. All of these factors had some effect of Rf values, on absolute FID responses and on reproducibility, but they were not the major cause of variability in the Iatroscan‐Chromarod system. Similarly, double developments improve peak shape and response, but results in only a small increase in precision for some compounds. The differences among the FID responses obtained from 10 rods within a set imply that the normalization of FID responses to that of an internal standard, or the use of intrarod rather than interrod data, should result in an increase in reproducibility. Neither of these approaches was found to improve the precision for all lipid classes. An understanding of both interrod and intrarod variability, and the use of calibration curves, is essential for accurate determination of the lipid classes of 1 liter of seawater.
Quantitative class separation of coal liquids using thin‐layer chromatography with flame lonization detection
Authors: Selucky M. L. 
Published: November 2006

AbstractThe paper illustrates the use of TLC/FID for the separation of heavy distillates and is a summary of work done by our group over the last few years and published in detail elsewhere. For those who are unfamiliar with fossil fuel analysis, the basic terms and methods are explained with emphasis on the merits and disadvantages of TLC/FID as compared to column and solubility separations. Also, problems with the determination of concentration/response dependence and with absolute detector calibration are outlined.