bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of cyclopropene fatty acids on the lipid composition of the Morris hepatoma 7288C
Authors: Zoeller Raphael A. , Wood Randall 
Published: November 2006

AbstractFatty acids ofSterculia foetida were added to the medium used to maintain the Morris hepatoma 7288C in culture. The effect of this supplement on the lipid composition was examined. Overall, monoene levels were decreased with 18∶1 levels reduced by 40%. Saturated fatty acid levels were increased, with stearate (18∶0) levels 220% of control values. No effect occurred on the level of polyunsaturates (18∶2, 20∶4, 22∶5, 22∶6). These changes in fatty acid makeup were observed in both neutral and phospholipid fractions, and all lipid classes were affected. Triglycerides were most affected with a 66% decrease in 18∶1. There appeared to be little specificity of effect in the phospholipids with 18∶1 levels decreased 40–60% in all classes. All classes were therefore dependent on an endogenous supply of 18∶1. Examination of the distribution of geometrical isomers of 18∶1 reveals that in all lipid classes, except diphosphatidylglycerol (DPG), the ratio of Δ11 to Δ9 isomer decreased toward the isomeric distribution displayed by total medium lipids. In DPG, although 18∶1 levels were lowered, the isomeric distribution increased. DPG, synthesized and found in the mitochondria, may use a separate pool of 18∶1 during synthesis. Cyclopropene fatty acids (sterculic and malvalic) were incorporated into both neutral and phospholipid fractions with preferential incorporation into triglycerides. Cyclopropene fatty acids were not selectively incorporated into any phospholipid species. Sphingomyelin did not incorporate cyclopropene fatty acids, indicating that a different class of acyltransferase is used in the formation of this phospholipid class.
Side‐chain structural requirements for sterol‐induced regulation ofPhytophthora cactorum physiology
Authors: Nes W. David , Stafford Allan E. 
Published: November 2006

AbstractThe influence of cholesterol. (E)‐17(20)‐dehydrocholesterol, sitosterol, (Z)‐17(20)‐dehydrocholesterol and 20‐isocholesterol on growth and sexual morphogenesis inPhytophthora cactorum has been examined. Optimal growth‐response and production of oospores occurred with the 3 former sterols, which posseesed “right‐handed” side chains (C22trans‐oriented to C13). Abnormal hyphae and aborted oospores were evident in mycelia cultured with sterols having side chains with “left‐handed” structures, i.e., 20‐isocholesterol and (Z)‐17(20)‐dehydrocholesterol. The induction of the sexual cycle lacked a selectivity for stereochemistry in the side chain. The results are interpreted to imply that fungal recognition of the sterol molecule in the reproductive phase of the life cycle is of 2 types: one involves discrimination of stereochemical features of the sterol side chain (oospore production); in the other, no functional significance can be attributed to conformation or configuration of side chain moieties (sexual structure induction). Growth response to dietary sterol seeems to fall into the former category.
Determination of the composition of mixed micelles of bile salts by kinetic dialysis
Authors: Lake M. , Organisciak D. T. 
Published: November 2006

AbstractA kinetic dialysis method for determining the critical micelle concentration and the composition of mixed micelles has been adapted to study a binary system of bile acids. Using kinetic dialysis, the critical micelle concentrations of taurocholate, deoxycholate and taurodeoxycholate were determined. Monomer analysis was performed by colorimetric and radioactive tracer techniques on aliquots of the dialysates. Similarly, the composition of mixed micelles made from various molar fractions of deoxycholate and taurocholate containing tritium and14C tracers were determined by this method. The results suggest that, for these bile acids, mixed micelle composition is largely predicted by the molar composition of the binary system. Kinetic dialysis has proven to be a rapid procedure and to yield results that agree with critical micelle concentration values previously reported.
Behavior of sugar derivatives in procedure for ganglioside isolation
Authors: Yates Allan J. , Warner Jean K. 
Published: November 2006

AbstractA common method of studying ganglioside metabolism is to measure the amounts of radioactivity incorporated into ganglioside from a radiolabeled precursor. This requires that radioactive nonganglioside material be completely removed from the ganglioside fraction. Nucleotide sugars and aminosugars comprise an important source of such contaminants. Therefore, we have studied their behaviors in several procedures currently employed to isolate gangliosides. Over 50% of the radioactivity associated with several nucleotide sugars added to a brain homogenate is extracted with chloroform/methanol (2∶1, v/v), and most of this is recovered in the upper phase of a Folch partition. Dialysis against water removes almost all of the free aminosugar but only 70% of nucleotide sugar. Treatment with alkaline phosphatase, phosphodiesterase and alkaline methanol followed by dialysis removes almost all of the nucleotide diphosphate sugars but only 88% of cytidine 5′‐monophosphate sialic acid (CMP‐NeuAc). Nucleotide sugars cannot be separated from gangliosides by Unisil or latrobead chromatography, but nucleotide diphosphate sugars and gangliosides are resolved with Sephadex LH‐20 chromatography following treatment with phosphodiesterase and alkaline phosphatase. CMP‐NeuAc was not satisfactorily separated from gangliosides using any of the procedures.
Increased lysolecithin acyltransferase activity in the plasma of type II hyperlipoproteinenic patients
Authors: Subbaiah Papasani V. , Ogilvie James T. 
Published: November 2006

AbstractLecithin‐cholesterol acyltransferase (LCAT) in human plasma has been shown to acylate lysolecethin to lecithin in presence of low density lipoprotein (LDL). To determine the physological importance of LDL in activating lysolecithin acyltransferase (LAT) activity, we assayed the LAT activity in 18 hypercholesterolemic (Type II) patients and 15 control subjects. The enzyme activity was about 60% higher in the patients compared with the controls. On the other hand, the LCAT activity, measured by 2 different procedures, as well as enzyme mass, determined by radioimmuno assay, were comparable in the controls and hypercholesterolemics. The LAT activity was highly correlated with LDL levels in the plasma, but the LCAT activity and the enzyme mass had no correlation with the LDL levels. These results show that the plasma LDL is the rate‐limiting activator of the enzyme, and pathological conditions, resulting in higher LDL levels, also cause higher LAT activities.
Cholesterol binding capacity of fiber from tropical fruits and vegetables
Authors: Lund Eric D. 
Published: November 2006

AbstractThe cholesterol binding capacity of 28 fiber samples from a variety of the more common tropical fruits and vegetables was determined. The binding capacity of cholestyramine, cellulose, lignin, guar gum and citrus pectin were also determined. Capacities were evaluated by an in vitro method that simulates the effect of the human digestive system on fiber using a series of enzymatic treatments before the binding was determined. Binding values varied from 3% for a soluble fraction of cassava to 84% for cholestyramine. Values for most fruit and vegetable fiber samples were less than or ca. equal to cellulose or lignin (20% and 16%, respectively). Apart from cholestyramine, sweet potato was the most effective binder (30%). Citrus pectin, at 8%, was a relatively poor binder. The capacity of guar gum (17%) was slightly less than cellulose. These data do not support the conclusion from in vivo studies that the hypocholesteremic effects observed for citrus pectin and guar gum are the result of the direct binding of cholesterol or bile acids in the large intestine.
Pathways of acetyl CoA production for lipogenesis from acetoacetate, β‐hydroxybutyrate, pyruvate and glucose in neonatal rat lung
Authors: Sheehan Patricia M. , Yeh Yu‐Yan 
Published: November 2006

AbstractThe rate of fatty acid synthesis from acetoacetate (AcAc) is 2–3 times greater than from glucose in developing rat lung. To determine the reason for this difference, we investigated the pathways of lipogenesis from [3‐14C] AcAc, [3‐14C]β‐hydroxybutyrate (βOHB), [U‐14C] glucose or [2‐14C] pyruvate in minced lung tissue of 3‐ to 4‐day‐old rats. The addition of (−)hydroxycitrate, an inhibitor of ATP‐citrate lyase, inhibited fatty acid synthesis from glucose, pyruvate, and βOHB by 88%, 70% and 60%, respectively, but had no effect on that from AcAc. Benzene 1,2,3‐tricarboxylate, an inhibitor of tricarboxylate translocase, inhibited fatty acid synthesis from all substrates by at least 50%. Incubation with aminooxyacetate, an inhibitor of aspartate aminotransferase, has no effect on lipid synthesis from glucose, pyruvate or AcAc, but increased lipid synthesis from βOHB. Results indicate that for lipid synthesis in the neonatal lung, acetyl CoA from AcAc is derived predominantly from a cytoplasmic pathway involving AcAcCoA synthetase and AcAcCoA thiolase, whereas citrate is the major route of acetyl group transfer from glucose. Lipogenesis from βOHB involves both the cytoplasmic and citrate pathways.
Effects of different levels of dietarytrans‐octadecenoate on steroid metabolism in rats
Authors: Watanabe Midori , Cho Young‐J. , Ide Takashi , Sugano Michihiro 
Published: November 2006

AbstractRats were fed semipurified diets containing olive oil or partially hydrogenated corn oil at the 5 or 20% level for ca. 30 days. These fat diets contained the same amount of octadecenoate but differed in the geometry with respect to each fat level. Contents oft‐18∶1 were 26% and 41% of total fatty acids, respectively. The linoleic acid content was also made equivalent (3.8 energy %). After feeding on cholesterol‐free diets, rats ontrans fat, compared to those oncis fat, showed: (a) no changes in serum cholesterol and apolipoprotein levels, (b) no effects on the bile flow and concentrations of biliary cholesterol or bile acids, (c) a trend toward increased fecal excretion of neutral and acidic steroids, (d) a lesser extent of transformation of cholesterol to coprostanol in the gut, and (e) no changes in the composition of biliary and fecal bile acids. Observations (c) and (d) were more marked with a hightrans fat regimen. These observations, except for serum apolipoproteins and fecal steroid excretion, were practically reproducible even when rats were fed cholesterol‐enriched diets.
Subcellular localization of triacylglycerol synthesis in spinach leaves
Authors: Martin B. A. , Wilson R. F. 
Published: November 2006

AbstractThe subcellular location of diacylglycerol acyltransferase (EC 2.3.1.20) in spinach leaves (Spinacia oleracea L. cv. Longstanding Bloomsdale) was determined after sucrose‐gradient centrifugation of tissue homogenates. Enzyme activity was associated primarily with gradient fractions containing oil bodies and intact chloroplasts. Gradient fractions enriched with the endoplasmic reticulum contained insignificant levels of diacylglycerol acyltransferase activity. On the basis of chlorophyll, diacylglycerol acyltransferase activity in crude homogenates was not significantly different from that in intact chloroplasts after Percoll density‐gradient centrifugation. Among membrane fractions isolated from hypotonically treated chloroplasts, envelopes contained the greatest diacylglycerol acyltransferase and galactosyltransferase activity. These data demonstrated that chloroplasts were a subcellular site for triacylglycerol biosynthesis in spinach leaves.
Effect of antioxidants on lipid peroxidation in iron‐loaded rats
Authors: Dillard Cora J. , Downey Jeanne E. , Tappel Al. L. 
Published: November 2006

AbstractIndirect evidence has suggested that lipid peroxidation is associated with iron overload in vivo. As a measure of lipid peroxidation, pentane expired in the breath of rats loaded with an accumulated dose of either 100 mg or 186–200 mg of iron injected intraperitoneally as iron dextran was measured over a 7 to 8 week period, and the effect on pentane production of feeding antioxidant‐supplemented diets was determined. By the seventh week of feeding the diets, rats fed 0.3% L‐ascorbic acid produced 17% less (P=0.03) pentane than did rats fed the basal antioxidant‐deficient diet, whereas rats fed 0.004% dl‐α‐tocopherol acetate produced 92% less (P<0.001). After being fed the basal diet for 7 weeks, iron‐loaded rats produced 76±9 pmol pentane/100 g body wt/min. When synthetic antioxidants were added to the diet at a concentration of 0.25%, the order of effectiveness in decreasing pentane production after 1 week was: N,N′‐diphenyl‐p‐phenylenediamine > ethoxyquin > butylated hydroxyanisole > butylated hydroxytoluene > propyl gallate ∼ no antioxidant. After removal of either ethoxyquin or N,N′‐diphenyl‐p‐phenylenediamine from the diets for 1 week, pentane production increased to a high level. The total amount of lipid soluble fluorophores in individual spleens of rats fed N,N′‐diphenyl‐p‐phenylenediamine, ethoxyquin, dl‐α‐tocopherol acetate, ascorbic acid and no antioxidant were correlated significantly with the corresponding total integrated amount of pentane produced by the individual rats over the 7 to 8 week period. This study has provided some of the most direct evidence to date that lipid peroxidation is associated with iron overload in vivo.
Analysis of triglyceride species by high‐performance liquid chromatography via a flame lonization detector
Authors: Phillips F. C. , Erdahl W. L. , Nadenicek J. D. , Nutter L. J. , Schmit J. A. , Privett O. S. 
Published: November 2006

AbstractThe analysis of triglyceride species by high performance liquid chromatography (HPLC) with a flame ionization detector (FID) and reversed‐phase chromatography using chemically bonded octadecyl silane (ODS) Zorbax columns and gradient or isocratic solvent elution with methylene chloride/acetonitrile is described. Triglycerides containing acyl groups of critical pairs,trans and positional isomers, as well as mixtures of even and odd chain lengths are separated. Identification of triglycerides is made on the basis of retention times compared with equivalent and theoretical carbon numbers, and comparison with chromatograms of reference triglyceride mixtures. The methodology is demonstrated by fractionizing the triglycerides of olive oil under different chromatographic conditions using single and coupled conventional 250×4.6 mm columns and a short 80×6.2 mm column for fast separations.
Polyunsaturated fatty acids and neutral lipids in developing larvae of the oyster,Crassostrea virginica
Authors: Chu Fu‐Lin E. , Webb Kenneth L. 
Published: November 2006

AbstractThe fatty acid composition of oyster larvae at various stages, as well as of the algal diet, were determined by gas liquid chromatography (GC). Saturated fatty acids are the major fatty acid components in all larval stages and account for 34–62%, 30–35% and 35–81% of the neutral, polar and total lipids of algal‐fed larvae respectively. Weight percentage of saturated fatty acid in “starved” larvae was consistently higher (63–81%) during the whole period. The total polyunsaturated fatty acids were higher in the polar lipids than in the neutral lipids. The concentration of the ω3 fatty acids also was comparatively higher in the polar lipids than in the neutral lipids. In the total and neutral lipid fractions, the weight percentage of polyunsaturated and ω3 fatty acids was higher in the eyed than in the pre‐eyed (pediveliger) larvae. Eicosapentaenoic acid (20∶5ω3) and 22∶6ω3 were not detected in lipids of “starved” and young larvae. There was an accumulation of 20∶5ω3, 22∶6ω3, and total ω3 fatty acids in the older larvae. Lipid classes were separated by thin layer chromatography (TLC). There was no qualitative change in lipid composition during larval development, but a marked increased of triacylglycerol in larvae up to the stage of maturation in algae‐fed larvae.
Inhibition of fatty acid synthesis in isolated adipocytes by 5‐(tetradecyloxy)‐2‐furoic acid
Authors: Halvorson David L. , McCune Sylvia A. 
Published: November 2006

AbstractThe compound 5‐(tetradecyloxy)‐2‐furoic acid (TOFA), a hypolipidemic agent, inhibits fatty acid synthesis, lactate and pyruvate accumulation and CO2 release in isolated at adipocytes. TOFA stimulates the accumulation of citrate. ATP levels are not lowered by TOFA. In comparison with the natural fatty acid, oleate, TOFA exhibited a much greater inhibitory effect on lipogenesis. TOFyl‐CoA formation within intact adipocytes was demonstrated. Although not inhibited by TOFA, acetyl‐CoA carboxylase is inhibited by TOFyl‐CoA. It is proposed that many of the metabolic effects of TOFA in isolated adipocytes can be explained by TOFyl‐CoA inhibition of acetyl‐CoA carboxylase. TOFA inhibits glycolysis as a secondary event with the primary event of inhibition of fatty acid synthesis causing an accumulation of citrate which is an inhibitor of phosphofructokinase.
Quantitative analysis of triglyceride species of vegetable oils by high performance liquid chromatography via a flame lonization detector
Authors: Phillips F. C. , Erdahl W. L. , Schmit J. A. , Privett O. S. 
Published: November 2006

AbstractA method for the quantitative analysis of triglyceride species composition of vegetable oils by reversed‐phase high performance liquid chromatography (RP‐HPLC) via a flame ionization detector (FID) is described. Triglycerides are separated into molecular species via Zorbax chemically bonded octadecylsilane (ODS) columns using gradient elution with methylene chloride in acetonitrile. Identification of species is made by matching the retention times of the peaks in the chromatogram with the order of elution of all of the species that could be present in the sample on the basis of a random distribution of the fatty acids and comparision of experimental and calculated theoretical carbon numbers (TCN). Quantitative analysis is based on a direct proportionality of peak areas. Differences in the response of individual species were small and did not dictate the use of response factors. The method is applied to cocoa butter before and after randomization, soybean oil and pure olive oil.
Heterogeneous labeling of adipocytes during in vivo‐in vitro incubation of epididymal fat pads of aging mice with [1‐14C] palmitate
Authors: Hill V. , Baker N. 
Published: November 2006

AbstractWe have hypothesized that the in vivo‐in vitro technique of Stein and Stein for studying free fatty acid incorporation into adipose tissue triglycerides and phospholipids may introduce artifacts due to diffusion barriers such as collagenous membranes, especially in fat pads of old animals. By using this technique in young and old mice and peeling the external cells, either physically or by collagenase treatment, we were able to show that the outer adipocytes are preferentially labeled. However, this pattern of heterogenous labeling occurred in fat pads of both young (10–14 weeks) and old (80 weeks) mice. Fat pads are known to develop thicker, collagenous outer membranes during aging. Therefore, it seems likely to us that the marked decrease in free fatty acid esterification in fat pads of old mice, using the in vivo‐in vitro method that we have described previously and confirmed here, could have been due to greater diffusion barriers in the tissues of the older mice.
Hypolipidemic effects of clofibrate and selected chroman analogs in fasted rats: II. High sucrose‐fed animals
Authors: Mukhopadhyay A. , Patel S. T. , O'Brien M. , Kokrady S. S. , Newman H. A. I. , Witiak D. T. , Lanese R. R. , Rice J. C. , Feller D. R. 
Published: November 2006

AbstractThe hypolipidemic properties of ethyl 6‐chlorochroman‐2‐carboxylate (II), 6‐phenylchroman‐2‐carboxylate (III) and 6‐cyclohexylchroman‐2‐carboxylate (IV) were compared to clofibrate (I) in sucrose‐fed fasted male Sprague‐Dawley rats. All compounds were administered at doses of 0.2 and 0.4 mmol/kg, orally, twice daily for 7 consecutive days. In this model, II was a more effective hypocholesterolemic drug than clofibrate, whereas III and IV were inactive. Chlorochroman II, like clofibrate, decreased serum α‐lipoprotein cholesterol and pre‐β‐lipoprotein triglyceride concentrations and concomitantly increased serum β‐lipoprotein triglyceride concentrations. In clofibrate‐treated rats, serum free cholesterol concentrations increased concurrent with a reduction in serum lecithin: cholesterol acyltransferase activity, but no such correlation was observed for II. Only II lowered liver cholesterol levels and increased liver triglyceride levels. No consistent inhibition of liver microsomal 3‐hydroxy‐3‐methylglutaryl‐CoA reductase activity was observed with these analogs. The observed changes in triglyceride and cholesterol concentrations among serum lipoproteins were of a greater magnitude after chlorochroman II and clofibrate administration to sucrose‐fed rats than in our previous studies using chow‐fed fasted rats. These data suggest that chloro‐substitution at the 6‐position of the phenylchroman ring is important for hypolipidemic activity of these cyclic clofibrate analogs.
Reversed‐phase thin layer chromatography of some common sterols
Authors: Domnas Aristotle J. , Warner Steven A. , Johnson Susan L. 
Published: November 2006

AbstractThe chromatographic mobilities of 17 sterols and squalene on reversed‐phase thin layer plates with four nonaqueous solvent systems is described. A degree of separation adequate to identify several of the sterols was obtained. It was possible to separate the pairs: cholestanol, epicholestanol; coprostanol, epicoprostanol; 5β‐cholestan‐3α and 3β‐ol and lanosterol, dihydrolanosterol.
Fatty acid composition ofIxiolaena brevicompta F. Muell. Seed Oil
Authors: Ford Glenn L. , Whitfield Frank B. , Walker Keith H. 
Published: November 2006

AbstractThe seeds ofIxiolaena brevicompta F. Muell. (family Compositae) contained an oil (12%) in which the major fatty acids present are palmitic (7%), stearic (5%), oleic (8%), linoleic (51%) and crepenynic ical and physical methods. The bioactivity of crepenynic acid is discussed with respect to extensive mortalities of sheep grazing on mature seededI. brevicompta.