bluuebunny/crossref_metadata_2025_split huggingface dataset:
The interaction of prostaglandin E1 with serum lipoproteins possible role in cholesterol homeostasis
Authors: Bergelson Lev D. 
Published: November 2006

AbstractProstaglandin (PG) E1 significantly stimulates the rate of cholesterol esterification in plasma. This effect could be attributed to an enhancement by PGE1 of the interlipoprotein transfer of phosphatidylcholine and cholesteryl esters,i.e., the substrate and product of lecithin‐cholesterol acyltransferase (LCAT). The enhancement effect appears to be due to a rearrangement of the lipoprotein surface induced by specific interaction of PGE1 with some apolipoproteins, although the binding capacity of serum lipoproteins for PGE1 was found to be rather weak. To explain these findings, an hypothetical non‐equilibrium model was put forward. The purpose of the present article is to summarize available data on the PGE1‐lipoprotein interaction.
Properties of an acid cholesteryl ester hydrolase inhibitor from rat serum
Authors: Tanaka Mitsuo , Iio Toshihiro , Tabata Toshikazu 
Published: November 2006

AbstractThe inhibitory effect of a protein isolated from rat serum on lysosomal acid cholesteryl ester hydrolase (acid CEH; EC.3.1.1.13) activity was studied. An inhibitor was purified from rat serum following ultracentrifugation and heat treatment using column chromatography on Sephacryl S‐200 and ultrafiltration. The purified inhibitor appeared as a single protein band in sodium dodecyl sulfate (SDS)‐polyacrylamide gel electrophoresis. The molecular weight of the inhibitor was 28,000 Daltons as judged by gel filtration on Sephacryl S‐200 and SDS‐polyacrylamide gel electrophoresis. The purified inhibitor was shown to be apolipoprotein A‐I (apo A‐I), the major apolipoprotein of high‐density lipoprotein (HDL), using immunoprecipitation with rat anti‐apo A‐I immunoglobulin (Ig)G. Inhibition of acid CEH activity by apo A‐I was dependent on the concentration of apo A‐I. The values of Vmax obtained were similar with or without apo A‐I. Apo A‐I of various other mammalian species, including human, bovine and rabbit, also inhibited acid CEH activity. Other apolipoproteins, such as apo A‐II and apo B, also showed inhibiting activity. On the other hand, apo A‐I had no effect on the activity of other enzymes found in lysosomes, such as cathepsin D, β‐glucuronidase and acid phosphatase. The results suggest that apolipoproteins may play a role in the regulation of hydrolysis of cholesteryl esters in lipoproteins, that have been transferred to the liver, and that the inhibition of acid CEH activity by apo A‐I may be a characteristic of the lipid‐binding protein or be due to changes of the lipid/water interface.
Effects of high α‐linolenate and linoleate diets on erythrocyte deformability and hematological indices in rats
Authors: Sakai Keiko , Okuyama Harumi , Kon Kazunori , Maeda Nobuji , Sekiya Misuzu , Shiga Takeshi , Reitz Ronald C. 
Published: November 2006

AbstractRats were fed either a high α‐linolenate diet or a high linoleate diet from weaning to 4 mon of age. Soybean oil was used as a control. Phospholipid compositions of erythrocytes from the three dietary groups were not significantly different. However, the difference in the α‐linolenate (18∶3n−3)/linoleate (18∶2n−6) ratio of the diets was reflected in the n−3/n−6 ratios of the 20 and 22 carbon highly unsaturated fatty acids except for docosahexaenoic acid (22∶6n−3) in the phospholipids. Despite the significant differences in the fatty acid compositions of phospholipids, no measurable differences were detectable in erythrocyte deformability, whole blood viscosity and hematological indices of the three dietary groups. These results indicate that the beneficial effects of the high α‐linolenate diet, as compared with the high linoleate diet, are exerted without significant changes in these parameters.
Reduced adipose 18∶3ω3 with weight loss by very low calorie dieting
Authors: Phinney Stephen D. , Tang Anna B. , Johnson Susan B. , Holman Ralph T. 
Published: November 2006

AbstractThe human undergoing rapid and sustained weight loss by very low calorie dieting (VLCD) derives the majority of daily energy needs from adipose fatty acids. To evaluate the rates of metabolic utilization of individual fatty acids in humans, two groups of adult women outpatients were studied during major weight loss by VLCD. The diets used were either food or formula, providing the recommended dietary allowance for minerals and vitamins, with fat contents of 2–20 g/d. Group 1 consisted of 10 subjects [initial body mass index (BMI) 32.7, 157% of ideal body weight (IBW)] with a mean loss of 17.7 kg in 3–5 months. Group 2 consisted of 14 subjects (initial BMI 36.7, 167% of IBW) with a mean loss of 25.6 kg in 4–5 months. Adipose tissue biopsies were obtained by needle aspiration from Group 1 before and after weight loss and from Group 2 before, at the midpoint, and after weight loss. With weight loss in Group 1, the adipose tissue content of 18∶1ω9, 18∶2ω6, and 20∶4ω6 did not change, but 18∶3ω3 fell (0.67 to 0.56 wt%, p<0.0001) as did 20∶5ω3 (0.08 to 0.05, p<0.01). Adipose tissue 22∶6ω3 rose from 0.03 to 0.07 (p<0.01). In Group 2, only 18∶3ω3 showed a change, falling from 0.71 to 0.69 to 0.59 wt% across weight loss (p=0.03 by analysis of variance). We conclude that the major fatty acids are oxidized in proportion to their composition in adipose triglyceride. The significant reduction in the concentration of 18∶3ω3 during weight loss is unique among fatty acids. Its accelerated removal from adipose tissue indicates either a preferential step in β‐oxidation or a defined need during supplemented fasting which exceeds its rate of provision from adipose stores.
Squalene in grapefruit wax as a possible natural protectant against chilling injury
Authors: Nordby Harold E. , McDonald Roy E. 
Published: November 2006

AbstractThe influence of temperature conditioning on stored grapefruit against chilling injury (CI) as related to the fruit's neutral lipids in the peel was investigated. Squalene, a highly unsaturated C30 isoprene hydrocarbon, was found to be present in the epicuticular wax of grapefruit. The optimal temperature for biosynthesis of squalene in grapefruit was 15°C; this is also the temperature reported previously as the optimum temperature for conditioning grapefruit against chilling injury. Control and temperature‐conditioned grapefruit were stored monthly over three seasons from 1986 to 1989. Fruits were rated for chilling injury and the levels of squalene were determined. An inverse relationship found between CI and squalene level suggested that squalene may protect grapefruit from CI.
Influence of dietary fish oil on the relative synthesis of triacylglycerol and phospholipids in rat liverin vivo
Authors: Yeo Young K. , Holub Bruce J. 
Published: November 2006

AbstractThe influence of dietary fish oil containing n−3 polyunsaturated fatty acids on the biosynthesis of triacylglycerol relative to total individual phospholipids was studied in rat liverin vivo. The dietary lipid (10% by weight of diet) was either sunflower oil enriched in linoleic acid (SO group) or MaxEPA fish oil/sunflower oil, 9∶1 by weight (FO group) enriched in eicosapentaenoic acid (EPA, 20∶5n−3) plus docosahexaenoic acid (DHA, 22∶6n−3). After a 3‐week feeding period, the triacylglycerol content (in μmmol/g liver) was 44% lower in the FO group relative to the SO animals. Thein vivo incorporation of [3H]glycerol into individual hepatic lipids resulted in triacyl‐glycerol/total phospholipid radioactivity ratios of 2.1 and 0.9 for the SO and FO groups, respectively. These results indicate an inhibitory effect of dietary EPA/DHA on triacylglycerol relative to phospholipid synthesis from intermediary 1,2‐diacylglycerol in rat liverin vivo. This metabolic alteration was accompanied by a substantially lower amount (in μmol/g liver) of arachidonic acid and higher levels of EPA plus DHA in the triacylglycerol, choline glycerophospholipid (CGP), and ethanolamine glycerophospholipid (EGP) of the FO group. A moderately higher labelling of the EGP from [3H]glycerol was observed in the FO as compared to the SO group (as evidenced by CGP/EGP radioactivity ratios of 1.3∶1 and 1.8∶1, respectively). The present study providesin vivo evidence for a dampening effect of dietary fish oil on the synthesis of liver triacylglycerol relative to phospholipid and a moderate alteration ofde novo synthesis of individual phospholipids.
Influence of dietary fatty acid composition on cholesterol synthesis and esterification in hamsters
Authors: Jones Peter J. H. , Ridgen Julie E. , Benson Alexander P. 
Published: November 2006

AbstractTo investigate the effects of dietary fat quality on synthesis and esterification of cholesterol, Syrian hamsters were fed diets containing corn, olive, coconut or menhaden oils (10% w/w) with added cholesterol (0.1% w/w). After 3 weeks, animals were sacrificed 90 min following IP injection of3H2O. Synthesis of free cholesterol and movement of free cholesterol into ester pools were measured from3H‐uptade rate in liver and duodenum. Plasma total cholesterol and triglycerides levels were highest in coconut oil‐fed animals, whereas hepatic total cholesterol and ester levels were elevated in olive oil‐fed animals, as compared with all other groups. No diet‐related differences were seen in duodenal cholesterol or total fatty acid content. In duodenum, uptake of3H per g tissue into cholesterol was greater compared with liver; however, within each tissue,3H‐uptake into cholesterol was similar across groups. Notably,3H‐uptake into cholesterol ester in liver was highest in menhaden oil‐fed animals. These data suggest that menhaden fish oil consumption results in enhanced movement of newly synthesized cholesterol into ester as compared with other fat types.
Synthesis of ω9‐tetracosynoic and ω9‐octacosynoic acids as entries into tritiated metabolic precursors ofcis‐9‐tricosene andcis‐9‐heptacosene in the housefly
Authors: George Pomonis J. , Hakk Heldur 
Published: November 2006

AbstractThe syntheses of 15‐tetracosynoic acid (ω9‐tetracosynoic acid) and 19‐octacosynoic acid (ω9‐octacosynoic acid) are described. These alkynoic acids are to be tritiated to the corresponding alkenoic acids, which will be used as metabolic precursors of housefly pheromone components. The final step in each synthesis involved the coupling of 1‐decyne to the lithio‐salt of the appropriate ω‐bromoacid. Homologation of dibromoalkanes was accomplished with triphasic catalytic displacement of bromide by cyanide ion. Oxidation of a bromo‐alcohol to a bromoacid was performed in benzene with KMnO4 and 18‐crown‐6 ether.
Effects of dietary n−3 and n−6 polyunsaturated fatty acids on macrophage phospholipid classes and subclasses
Authors: Chapkin Robert S. , Carmichael Suzan L. 
Published: November 2006

AbstractThis study examined the effects of n−3 and n−6 polyunsaturated fatty acid alimentation on murine peritoneal macrophage phospholipids. Mice were fed complete diets supplemented with either corn oil predominantly containing 18∶2n−6, borage oil containing 18∶2n−6 and 18∶3n−6, fish/corn oil mixture containing 18∶2n−6, 20∶5n−3 and 22∶6n−3, or fish/borage oil mixture containing 18∶2n−6, 18∶3n−6, 20∶5n−3 and 22∶6n−3. After two weeks, the fatty acid levels of glycerophosphoserines (GPS), glycerophosphoinositols (GPI), sphingomyelin (SPH), and of the glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE) phospholipid subclasses were determined. We found that mouse peritoneal macrophage GPC contain primarily 1‐0‐alkyl‐2‐acyl (range for the dietary groups, 24.6–30.5 mol %) and 1,2‐diacyl (63.2–67.2 mol %), and that GPE contains 1‐O‐alk‐1‐enyl‐2‐acyl (40.9–47.4 mol. %) and 1,2‐diacyl (44.2–51.2 mol %) subclasses. In general, fish oil feeding increased macrophage 20∶5n−3, 22∶5n−3 and 22∶6n−3 levels while simultaneously reducing 20∶4n−6 in GPS, GPI, GPE and GPC subclasses except for 1‐O‐alk‐1′‐enyl‐2‐acyl GPC. Administration of 18∶3n−6 rich diets (borage and fish/borage mixture) resulted in the accumulation of 20∶3n−6 (2‐carbon elongation product of 18∶3n−6) in most phospholipids. In general, the novel combination of dietary 18∶3n−6 and n−3 PUFA produced the highest 20∶3n−6/20∶4n−6 phospholipid fatty acid ratios. This study demonstrates that marked differences in the responses of macrophage phospholipid classes and subclasses exist following dietary manipulation. The reduction of 20∶4n−6, while simultaneously increasing 30∶3n−6 and n−3 PUFA levels, may be important in relation to the putative beneficial effects of 20∶3n−6 and fish oil on macrophage eicosanoid and platelet activating factor (PAF) biosynthesis.
Identification of naturally occurringtrans, trans Δ5,9 fatty acids from the spongePlakortis halichondroides
Authors: Carballeira Néstor M. , Shalabi Fathi 
Published: November 2006

AbstractThe firsttrans fatty acids from a sponge have been isolated fromPlakortis halichondroides. The sponge was shown to contain theiso acids (5E,9E)‐19‐methyl‐5,9‐eicosadienoic, (5E,9E)‐20‐methyl‐5,9‐heneicosadienoic and (5E,9E)‐21‐methyl‐5,9‐docosadienoic acid, as well as theanteiso acids (5E,9E)‐19‐methyl‐5,9‐heneicosadienoic and (5E,9E)‐20‐methyl‐5,9‐docosadienoic acid together with the straight chain (5E,9E)‐5,9‐docosadienoic acid. The acids were shown by gas chromatography, Fourier transform infrared and13C nuclear magnetic resonance to contain thetrans configuration. An eicosadienoic acid, namely (6E,14E)‐6,14‐eicosadienoic acid, and 12‐methyl‐5‐octadecenoic acid were also identified in a sponge for the first time. The fatty acids were shown to be the principal constituents of phosphatidylethanolamine and phosphatidylcholine. No sterols were found in the sponge. The results presented in this work should be helpful in taxonomy of Homoscleromorpha.
Purification and specificity of lipases fromGeotrichum candidum
Authors: Baillargeon Mary Welch 
Published: November 2006

AbstractA crude, commercialGeotrichum candidum lipase (EC 3.1.1.3) preparation (Amano GC‐20) was purified by hydrophobic interaction chromatography on Octyl Sepharose. The purified enzyme is a microheterogeneous glycoprotein containing isozymes varying in molecular weight, pI and specificity. It consists of 64, 62 and 59 kDa species as determined by denaturing polyacrylamide gel electrophoresis. Five isozymes (pI 4.40, 4.47, 4.58, 4.67 and 4.72) are detected by isoelectric focusing using both silver and activity stains. Chromatofocusing was used to separate the isozymes according to pI. Although all the isozymes are specific for oleatevs stearate esters, one isozyme (pI 4.72) is also specific for oleatevs palmitate. The number of isozymes is reduced to two (pI 4.67 and 4.72) after carbohydrate removal using endoglycosidase F/N‐glycosidase. These isozymes may be products of two lipase genes.
Formation of 8,15‐dihydroxy eicosatetraenoic acidvia 15‐ and 12‐lipoxygenases in fish gill
Authors: German J. B. , Berger Ralf 
Published: November 2006

AbstractMetabolites of arachidonic acid are important regulators of biological function in a variety of mammalian tissues. We have demonstrated similar lipoxygenase enzyme activities in fish gills and mammalian lungs suggesting that their metabolites may have matching functions. Fish gills were investigated for their ability to generate dioxygenated metabolites of polyunsaturated fatty acids. Fatty acids, including arachidonic acid, were incubated with crude tissue homogenates and polar metabolites were extracted, derivatized and analyzed by high performance liquid chromatography, gas chromatography and mass spectrometry. The major dihydroxy metabolite of arachidonic acid was characterized as 8(LR), 15(LS)‐dihydroxyeicosatetraenoic acid. This product was formed by the sequential action of the 15‐ and 12‐lipoxygenases in the tissue. The formation of the dihydroxyeicosatetraenoic acid by crude tissue homogenates was significantly enhanced by the addition of 1 mM reduced glutathione. The metabolism of other polyunsaturated fatty acids, including eicosapentaenoic acid and docosahexaenoic acid, to dihydroxy acids was consistent with their relative ability to serve as substrates for the initial 15‐lipoxygenase reaction.
The metabolism of 20‐ and 22‐carbon unsaturated acids in rat heart and myocytes as mediated by feeding fish oil
Authors: Mohammed B. Selma , Hagve Tor‐Arne , Sprecher Howard 
Published: November 2006

AbstractWhen rats were fed 5% corn oil, the heart phospholipids contained large amounts of 22‐carbon (n−6) acids. When half of the corn oil was replaced with fish oil, the reduced level of arachidonate and 22‐carbon (n−6) acids in phospholipids was accompanied by increases in the levels of 22‐carbon (n−3) acids while only small amounts of 20∶5(n−3) were acylated. Heart myocytes readily took up and acylated [1‐14C]‐labeled 20∶4(n−6), 20∶5(n−3) and 22∶6(n−3) into phospholipids. The uptake and acylation of 20∶4(n−6) was greater than for 20∶5(n−3) but the intracellular labeling profiles were similar. Uptake and acylation of 22∶6(n−3) was somewhat lower. In addition the intracellular labeling profile differed in that more 22∶6(n−3) was incorporated into the ethanolamine‐containing phospholipids than when 20∶4(n−6) or 20∶5(n−3) were the substrates. Neither 20∶4(n−6) nor 20∶5(n−3) was chain elongated. When [3‐14C]‐labeled 22∶4(n−6) and 22∶5(n−3) were the substrates, it was not possible to detect radioactive 22∶5(n−6) or 22∶6(n−3). Both [3‐14]‐labeled substrates were acylated into phospholipids and retroconverted with the subsequent esterification of radioactive 20∶4(n−6) and 20∶5(n−3) into triglycerides and phospholipids. These studies show that cardiomyocytes lack the ability to make 22‐carbon acids from 20‐carbon precursors but they retroconvert 22‐carbon acids to 20‐carbon acids. The high levels of 22‐carbon polyunsaturated acids in total heart lipids thus cannot be attributed to the synthetic capacities of cardiomyocytes.
Separation of 20∶4n−6 and 20∶4n−7 by capillary gas‐liquid chromatography
Authors: Wolff Robert L. , Sebedio Jean‐Louis , Grandgirard Andre 
Published: November 2006

AbstractThe use of a capillary column coated with 100% cyanopropyl polysiloxane (CPTMSil 88) allows the separation of several fatty acids associated with fat deficiency. Starting with liver mitochondrial phospholipids of weanling rats fed a fat‐free diet, an unusual fatty acid was isolated, along with 20∶4n−6, by thin‐layer chromatography on AgNO3‐impregnated silica gel plates. After partial hydrazine reduction of these acids, the resulting monoenes were isolated and subjected to ozonolysis in BF3/methanol. The resulting monomethyl and dimethyl esters were identified by gas chromatography/mass spectrometry. Our data indicate that the unusual component corresponds to 20∶4n−7. Based on published biochemical and analytical studies and on our own chromatographic retention data, some of the other unusual fatty acids were tentatively identified as 18∶2n−7, 20∶2n−7 and 20∶3n−7. The CPTMSil 88 column appears to be a simple and useful tool for the separation of fatty acids of the palmitoleate series.
The effect of bleomycin on the uptake and incorporation of [14C] choline into phospholipids in hamster lung tissue slices
Authors: Hollinger Mannfred A. , Giri Shri N. 
Published: November 2006

AbstractIntratracheal administration of the anticancer drug bleomycin to hamsters produced an increase in the uptake and incorporation of [14C] choline into phospholipids of lung slicesin vitro. The stimulatory effect is opposite to the results obtained previously using [14C] acetate and would appear to occur distal to cytidine diphosphocholine. Although alternate explanations are possible, the results are consistent with morphological evidence, published by others, indicating an increase in lung phospholipid following bleomycin treatment, and illustrate the significance of precursor selection when evaluating the effects of xenobiotics on phospholipid synthesis.
Phosphatidylcholine as substrate for human pancreatic phospholipase A2. Importance of the physical state of the substrate
Authors: Borgström Bengt 
Published: November 2006

AbstractThe long‐chain phosphatidylcholine/sodium cholate aqueous system as substrate for human pancreatic phospholipase A2 (PLA2) was investigated. At a constant phosphatidylcholine (PC) concentration of 8 mM, the enzyme activity increased with a decrease in cholate (C) concentration up to a PC/C ratio of approximately 0.8 and then rather abruptly decreased to lower values at a ratio above 1.5. At ratios between 0.8 and 1.5, an increasing lag phase in the PLA2 activity was seen, indicating a progressive decrease in substrate availability to the enzyme. Reaction mixtures with a PC/C ratio of up to 0.67 were optically clear solutions composed of mixed bile salt/PC micelles of increasing mixed micellar aggregate size. Ratios between 0.67 and 1.5 were characterized by an increase in turbidity (at 330 and 450 nm) due to increasing formation of vesicles or liposomes. Above a PC/C ratio of 1.5, a sharp increase in turbidity was seen due to increasing formation of bilayer structures other than vesicles. Pure vesicles obtained by dialysis of mixed micellar solutions were not hydrolyzed by the enzyme. Addition of bile salts reversed the inhibition which was accompanied by a decrease in turbidity. Phosphatidylcholine was preferred as substrate for human PLA2 when present in large mixed disc‐like bile salt micelles. Vesicular or other types of lamellar liquid‐crystalline phases of long‐chain phosphatidylcholine did not serve as substrate for PLA2.
Purification and properties of an extracellular lipase fromPythium ultimum
Authors: Mozaffar Zahid , Weete John D. 
Published: November 2006

AbstractAn extracellular triacylglycerol lipase (EC 3.1.1.3) fromPythium ultimum strain No. 144 was purified by ammonium sulfate precipitation, and by diethylaminoethyl Sepharose CL‐6B and Sephacryl S−200 chromatography. The purified enzyme preparation showed a prominent polypeptide band in polyacrylamide gel electrophoresis, associated with esterase activity according to activity staining. Molecular weight of the protein was estimated at 270 kD using gel filtration on Sephacryl S−200, and 68 kD by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis indicating that the enzyme may be a tetramer. The optimum pH and temperature for activity of the enzyme were 8.0 and 30°C, respectively. Activity was reduced by Co2+, Fe2+, Sn2+ and Mn2+ and stimulated by Ca2+, Mg2+, Na+, K+ and surfactants such as taurocholic acid, Triton X−100,n‐octyl glucoside,n‐dodecyl‐β‐D‐maltoside, 3‐[(3‐cholamidopropyl) dimethylammonio]‐1‐propanesulfonate(CHAPS), and 3‐[‐cholamidopropyl)dimethylammonio]‐2‐hydroxy‐1‐propanesulfonate. The apparent maximum specific activity was 42 μmole/min/mg in the absence of CHAPS and 77 μmole/min/mg in its presence. The reaction rate was progressively higher with increasing number of double bonds in the substrate, and the enzyme showed a preference for triacylglycerols containing fatty acids having thecis double bond configuration.