bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of mixtures of stigmasterol, stigmastanol and sitosterol
Authors: Rosenstein Fumiko U. , Kircher Henry W. 
Published: November 2006

AbstractHydrogenation of stigmasterol yields mixtures of the three title sterols. Stigmasterol was clearly separated from the other two by gas liquid chromatography; a standard curve was constructed relating the height of its peak to its concentration in the mixture. The total unsaturation was measured by a dibromopyridine sulfate‐thiosulfate procedure. The unsaturation contributed by previously determined stigmasterol was subtracted from the total to leave that contributed by sitosterol, whose concentration in the mixture was then calculated. The amount of stigmastanol, whose presence was qualitatively determined by thin layer chromatography after bromination of the mixture on the plate, was obtained by difference. When suitable corrections were made, based on analysis of known mixtures, the concentrations of three sterols in hydrogenation mixtures could be calculated.
Autoxidation of polyunsaturated fatty esters on Silica
Authors: Slawson Vida , Adamson Arthur W. , Mead James F. 
Published: November 2006

AbstractThe stability of unsaturated methyl esters of fatty acid adsorbed on silica gel and silicic acid was studied by gas liquid chromatographic estimation of disappearance relative to a saturated internal standard. Variables included silica‐ester ratio, agitation, adsorbent particle size, and degree of unsaturation. Under the conditions of the experiment, destruction of substrate unsaturated ester at 80 C was more a function of time than of unsaturation or initial purity.
Cholestanol and plant sterols in pigeon skin
Authors: Ravi Subbiah M. T. 
Published: November 2006

AbstractCholestanol (4.6%) and plant sterols (0.2%) have been demonstrated, for the first time, in avian skin by argentation and gas liquid chromatography. In contrast to results of previous studies with rat and human skin, cholestanol represented a significant amount in the pigeon. The proportion of campesterol was always higher than that of β‐sitosterol.
Tumor lipids: Comparison of glyceryl ethers of mouse and insect tumors
Authors: Welch Mary F. 
Published: November 2006

AbstractExamination of the lipids of two tumor‐bearing mutant strains of fruit fly reveal that they do not have the elevated content of glyceryl ethers typical of many neoplasms of higher animals. Glyceryl ether diesters were absent, and the amounts of alkyl and alk‐1‐enyl glyceryl ethers of tumorous and normal tissues were similar.
Polyprenols of beef and human pituitary glands
Authors: Carroll K. K. , Vilim A. , Woods M. C. 
Published: November 2006

AbstractAn unknown lipid previously isolated in our laboratory from beef and human pituitaries was shown to have the same structure as dolichol from pig liver. Beef pituitaries contained ca. 130 mg/kg wet tissue, of which ca. 25% was esterified to fatty acids. Human pituitaries contained ca. 1.4 g/kg, mainly as the free alcohol.
Dimorphotheca sinuata lipoxygenase: Formation of 13‐L‐hydroperoxy‐cis‐9,trans‐11‐octadecadienoic acid from linoleic acid
Authors: Gardner H. W. , Christianson D. D. , Kleiman R. 
Published: November 2006

AbstractLipoxygenase (EC 1.13.1.13) from the seed ofDimorphotheca sinuata oxidized linoleic acid to predominantly 13‐L‐hydroperoxy‐cis‐9,trans‐11‐octadecadienoic acid. When the reaction proceeded at pH 6.9, the 13‐hydroperoxide was the only isomer detected; but at pH 5.1, the 13‐isomer was 92% of the total, the remaining 8% being the 9‐hydroperoxide. At both pH's small amounts of hydroxyoctadecadienoic acid accumulated during the reaction. This acid from the pH 6.9 reaction was analyzed as 13‐hydroxy‐cis,trans‐octadecadienoic. The postulate advanced by many workers that dimorphecolic acid, 9‐D‐hydroxy‐trans‐10,trans‐12‐octadecadienoic acid, is biosynthesized via a lipoxygenase product was not proved. Although the product specificity ofD. sinuata lipoxygenase is like that of lipoxygenase type 1 from soybeans, its inactivity at pH 9 demonstrated that it is a novel enzyme.
Regulation of hepatic cholesterol synthesis from mevalonate in suckling and weaned rats
Authors: Shah S. N. 
Published: November 2006

AbstractThe conversion of mevalonic acid into total nonsaponifiable lipids (NSF) and digitonin precipitable sterols (DPS) by 5000 g liver supernatant fractions was compared in suckling and weaned rats. The incorporation of mevalonate into both NSF and DPS was low in fractions from suckling rats and very high in fractions from weaned rats. The results indicate that the activities of one or more of the enzymes catalyzing the conversion of mevalonate into squalene and squalene into cholesterol change after weaning and may act as regulatory step(s) for cholesterol synthesis in the livers of suckling rats. It is suggested that the reduced synthesis of cholesterol in the liver of suckling rats is caused by the cholesterol in the maternal milk, and the rapid rise in cholesterol synthesis after weaning is due in part to the dietary change accompanying weaning, and in part to an increased need for cholesterol by developing liver.
Changes in structure of triglycerides from maturing kernels of corn
Authors: Weber Evelyn J. 
Published: November 2006

AbstractKernels of corn inbred H51 were collected at five intervals after hand pollination. The triglyceride content of the total lipids increased from 8.6% at 10 days after pollination to 78.3% at 60 days. The most active period of triglyceride synthesis occurred from 20 to 45 days after pollination, when the weight of triglycerides per kernel increased from 1.1 to 7.5 mg. Over all the collection periods the percentages of palmitic, linoleic and linolenic acids decreased while oleic acid increased, but from 30 to 60 days after pollination the fatty acid composition of the triglycerides was nearly constant. Stereospecific analysis revealed a general fatty acid pattern for the triglycerides, in which the concentration of the saturated acids was highest in position 1, linoleic acid in 2 and oleic acid in 3. From 20 to 60 days after pollination there was little change in the fatty acid composition at the 1 position, but the largest changes occurred at the 3 position where palmitic and oleic acids decreased 5.1% and 7.3%, respectively, and linoleic acid increased 13.4%. The variations in the molecular species of the triglycerides were determined by silver nitrate thin layer chromatography and were found to be small from 20 to 60 days after pollination, except for an increase in trilinolein from 5.2 to 11.9%. Stereospecific analyses of four major triglycerides species, SMD, M2D, SD2, and MD2, revealed larger changes in fatty acid distribution at individual positions during maturation than were apparent from analyses of the total triglycerides.
Absorption and biliary secretion of intraperitoneally injected 3β‐methoxycholest‐5‐ene‐4‐14C in the rat
Authors: Norcia L. N. 
Published: November 2006

AbstractFollowing ip injection of 1 mg amounts of methoxycholestene‐4‐14C into normal intact rats, the amount of label in the whole liver was measured at different time intervals in different animals. These studies indicated that most of the injected compound was absorbed by or before 12 hr. In bile duct‐cannulated rats the secretion of label from ip injected methoxycholestene‐4‐14C or cholesterol‐4‐14C into bile was usually less during the first 24 hr than during the second 24 hr after injection. Studies on the nature of the labeled compounds in the bile following ip injection of methoxycholestene‐4‐14C indicate that most of the label is present in metabolites, 47% of the label in cholic acid and 31% in chenodeoxycholic acid.
Occurrence of (+)‐erythro‐2,3‐dihydroxyhexacosanoic acid in cerebrin from the yeastSaccharomyces cerevisiae
Authors: Proštenik M. , Kljaic K. , Weinert M. 
Published: November 2006

Abstract(+)‐Erythro‐2,3‐dihydroxyhexacosanoic acid was found in a mixture of cerebrins (ceramides containing sphingosines and phytosphingosines) from the yeastSaccharomyces cerevisiae. The structure was deduced on the basis of elemental analyses, gas liquid chromatography and thin layer chromatography of the appropriate derivatives of the acid and its oxidation products.
α‐Oxidation of 2‐hydroxy tetracosanoate in the rat
Authors: Lippel Kenneth , Mead James F. 
Published: November 2006

AbstractFour hours after oral administration of uniformly tritiated 2‐hydroxy tetracosanoate, most of the dose was recovered in the lipids of the digestive organs and liver of the rat. In contrast to the unchanged substrate detected in the lipids of the stomach tissue, the radioactivity recovered from the cells of the intestine and from the liver was predominatly in saturated fatty acid moieties of complex lipids and the small per cent of recovered hydroxy tetracosanoate was also incorporated into these lipids.
A rapid microozonolysis‐GLC procedure for locating unsaturation in olefinic acids, including trienes and tetraenes
Authors: Kleiman R. , Spencer G. F. , Earle F. R. , Wolff I. A. 
Published: November 2006

AbstractIncreased versatility has been achieved in the identification of unknown olefinic fatty acids by ozonolysis. The method has been applied to purified methyl esters containing up to four double bonds. Aldehydic fragments, obtained from esters by the Stein‐Nicolaides procedure (2), were determined by GLC on two columns of different polarity. Equivalent chain lengths of each fragment on the two columns provide identification. For monoenoic esters the location of the double bond is clearly indicated by the aldehyde and aldehyde‐ester fragments. Dienes are identified by the aldehyde and aldehyde‐ester fragments when the original chain length of the ester is known; the dialdehyde fragment provides confirmatory evidence. Trienes and tetraenes are analyzed by interrupting the ozonolysis at various times, thereby producing unsaturated, as well as saturated, aldehydes and aldehyde‐esters. Unsaturated fragments locate the central or interior double bonds.
GLC analysis ofHeliothis virescens triglycerides at various metamorphic stages
Authors: Wood Randall , Harlow R. D. , Lambremont Edward N. 
Published: November 2006

AbstractThe triglycerides ofHeliothis virescens (F.), the tobacco budworm, reared on a semidefined diet, were examined at different stages of development. The distribution of triglyceride carbon numbers and the composition of triglyceride fatty acids were determined by gas‐liquid chromatographic analysis of intact triglycerides and methyl esters. Triglycerides of carbon number 50 decreased in the unfed adults with age; the decrease corresponded with a decrease in palmitic acid. Linoleic acid and carbon number 50 exhibited fluctuations in concentrations that were correlated with metamorphosis. The observed changes in specific triglyceride carbon numbers with a simultaneous change in specific triglyceride fatty acids indicate a nonrandom fatty acid distribution in the triglycerides of this insect.
Effect of neonatal food restriction and hyperphenylalaninemia on desmosterol to cholesterol (D/C) ratio in developing rat brain
Authors: Shah S. N. 
Published: November 2006

AbstractThe sterol content and the ratio of desmosterol to cholesterol (D/C ratio) in brains of undernourished and hyperphenylalaninemic rats were measured. Neonatal food restriction resulted in a high D/C ratio, but the total sterol content did not change significantly. Phenylalanine treatment had no appreciable effect on the D/C ratio, but the total sterol content was reduced. The results suggest that neonatal food restriction leads to a block at the desmosterol reductase step, while treatment with phenylalanine inhibits sterol synthesis at a step prior to desmosterol.
Effect of biliary obstruction on canine plasma and biliary lipids
Authors: Quarfordt S. H. , Oelschlaeger H. , Krigbaum W. R. , Jakoi L. , Davis R. 
Published: November 2006

AbstractThe common bile duct was obstructed in 17 dogs. Reciprocal changes were noted for the plasma and biliary lipid concentrations of each after obstruction. As the plasma lecithin and free cholesterol concentrations increased, the biliary lipid concentrations declined. After biliary obstruction the reflux of biliary lecithin into the plasma of these animals was demonstrated with both labeled and unlabeled lecithin. The plasma lipid abnormalities seen after acute biliary obstruction were closely simulated by the reflux of lecithin alone from the biliary tree. The isolated reflux of biliary tract taurocholate produced a distinct lowering of plasma phospholipid and cholesterol concentrations, quite different from the plasma lipid alteration noted with acute biliary obstruction. Similar to observations in human obstruction, some of the plasma lipid was in mesophase form after these animals were obstructed.
Volume‐dependent transfer of free fatty acids from ehrlich ascites carcinoma to host tissues
Authors: Mermier Pierre , Baker Nome 
Published: November 2006

AbstractThe recovery of [9.10‐3H] palmitate complexed to mouse serum albumin was studied 5 sec after ip injection into mice bearing Ehrlich ascites carcinomas. Only about 55% of the injected radioactivity remained in the tumor cells, tumor extracellular fluid and peritoneal washings in mice having ca. 5 ml of the ascites tumor (cells plus extracellular fluid). However the recoveries were nearly quantitative from tumors of larger volume (≥8 ml). A model is proposed to account for the volume‐dependent transfer of palmitate from tumor to host in these cancerous mice.
Reduction of atherogenicity of natural fats by small additions of ethyl linoleate in the diet of the rat
Authors: Hutsell T. C. , Quackenbush F. W. 
Published: November 2006

AbstractEthyl linoleate was substituted in part for the 20% of butterfat, hydrogenated coconut oil, lard, or tallow in an atherogenic diet fed to rats throughout a 40‐week experimental period. Aortic degeneration, evidenced by lipid infiltration of the intima, was observed in the control groups but not in the linoleate‐fed groups. Groups that received butterfat or hydrogenated coconut oil showed reduced plasma and hepatic cholesterol levels when fed 2% of ethyl linoleate; groups that received lard or tallow showed no significant change in plasma and hepatic cholesterol levels when fed 2% of ethyl linoleate; and groups that received a fat‐free diet with 2% of ethyl linoleate showed lower plasma and hepatic cholesterol levels and more complete aortic protection than groups that were fed 20% of corn oil or cottonseed oil. The data suggest that, in the cholesterol‐fed rat, the kind and amount of dietary fatty esters may influence aortic condition via some route(s) other than control of plasma and hepatic cholesterol levels.
Regulatory function of pyruvate dehydrogenase and the mitochondrion in lipogenesis
Authors: Mapes J. P. , Harris R. A. 
Published: November 2006

AbstractThe activity of pyruvate dehydrogenase from freshly isolated mitochondria was shown to be dependent upon the nutritional and metabolic state of the animal prior to sacrifice, such that mitochondria from the livers of 48 hr starved, diabetic, or high fat fed rats had lower enzyme activity than normal, chow fed rats. The activity of pyruvate dehydrogenase and the rate of lipogenesis were shown to correlate to a certain extent when a reconstituted, cell free system consisting of 105,000 x g supernatant of rat liver and isolated mitochondria was used. This system was employed so that the role of the mitochondrion and pyruvate dehydrogenase in lipogenesis could be investigated. Dichloroacetate increased the activity of pyruvate dehydrogenase and increased the rate of lipogenesis, suggesting that the activity of pyruvate dehydrogenase is an important factor in determining the rate of lipogenesis in the reconstituted system. It was observed, however, that dichloroacetate was more effective in stimulating the activity of pyruvate dehydrogenase than the rate of lipogenesis when mitochondria from starved animals were used to reconstitute lipogenesis. Furthermore, the cytoplasmic adenosine triphosphate/adenosine diphosphate ratios and phosphorylation potentials (ATP/ADP×Pi) maintained in the reconstituted system by mitochondria isolated from starved animals were found to be significantly lower than those maintained by mitochondria isolated from chow fed animals. It is proposed that the lower “energy pressure” maintained in the reconstituted system by mitochondria isolated from starved animals severely limits lipogenesis at the ATP requiring steps of the process.
Quantitative, multicomponent analysis of fatty acids from cholesteryl esters by chemical ionization reconstructed mass chromatography
Authors: Petty F. , Ragland J. B. , Kuiken L. B. , Sabesin S. M. , Wander J. D. 
Published: November 2006

AbstractReconstructed mass chromatography using methane as a carrier and reagent gas for chemical ionization gas chromatography‐mass spectrometry of the derived methyl esters allows rapid, quantitative microdeterminations of complete cholesteryl ester fatty acid profiles. The sensitivity of this method is consistent with completely specific, multicomponent assay at the picomole level. Introduction of two homologues as internal standards, one into the intact biological specimen and the other after derivatization, provides a measure of the net efficiency of the processes of extraction and derivatization. This procedure may be extended readily to the determination of fatty acid profiles in most biological fluids.
Fat metabolism in higher plants: Metabolism of medium chain fatty acids
Authors: Sodja Ann , Stumpf P. K. 
Published: November 2006

AbstractCell free preparations of avocado mesocarp and spinach leaf tissue rapidly convert lauryl CoA to DL‐3‐hydroxyl lauric acid as well as 2−, and 3‐dodecanoic acids. The conversion does not occur under anaerobic conditions unless a suitable redox carrier such as ferredoxin is present. H218O is incorporated into the 3‐hydroxyl function, but O218 is not. The characteristics of this system are presented and a possible function of this system is proposed.
Reaction of ergosteryl acetate with maleic anhydride and preparation of 5,7‐ergostadien‐3β‐ol
Authors: Kircher H. W. , Rosenstein F. U. 
Published: November 2006

AbstractAn improved, large scale synthesis of the ergosteryl acetate‐maleic anhydride Diels‐Alder adduct and its pyrolysis are described. The complex mixture obtained by reaction of the two constituents was refluxed with methanol to convert the succinic anhydride derivatives, formed by the “ene” reaction, to soluble half esters, leaving the insoluble Diels‐Alder adduct largely unchanged. The latter was hydrogenated and pyrolyzed in vacuo to yield 5,7‐ergostadienyl acetate together with lesser quantities of the acetates of 7,9(11)‐ergostadien‐3β‐ol, 6,8(9)‐ergostadien‐3β‐ol, and 8,14‐ergostadien‐3β‐ol. These components were separated and purified by argentation column chromatography and crystallization.
Effects of structural variation in β‐monoglycerides and other lipids on ordering in synthetic membranes
Authors: Taylor A. R. , Roubal W. T. , Varanasi U. 
Published: November 2006

AbstractStudies of β‐monoglyceride multilayers were carried out using a variety of spin probes. Effects of variables such as chain length, unsaturation, and branching on organization of acyl chains in lipids of model membranes were assessed. In addition, effects of added cholesterol on membrane order were determined. Results indicated that pure β‐monolaurin yields highly ordered films, whereas, unsaturated glycerides such as β‐monoolein, β‐monolinolein, and analogous lecithins yield fluid films. Branched monoglycerides behaved similarly to β‐monoolein, suggesting that branching in acyl chains is an effective substitute for unsaturation in maintaining membrane integrity. Multilayers of β‐monoglycerides exhibited similar properties to those of more complex lipids such as phospholipids. β‐Monoglycerides, by virtue of the presence of a single acyl chain, provided a relatively simple and effective alternative to the use of phospholipids in studies of membrane architecture.
Sterols of the adult and juvenile forms of ivy,Hedera helix L.
Authors: Hillman J. R. , Knights B. A. , McKail R. 
Published: November 2006

AbstractSterols have been isolated from both adult and juvenile ivy in free and esterified form. Stigmasterol or its C‐24 isomer, poriferasterol, is the main component, and lesser amounts of sitosterol, α‐spinasterol, 5α‐stigmast‐7‐en‐3β‐ol, cholesterol, and campesterol also were detected. Flowers and fruits were found to contain a glycoside fraction in which stigmasterol, together with some sitosterol, could be detected.
High levels of pancreatic nonspecific lipase in rattlesnake and leopard shark
Authors: Patton John S. 
Published: November 2006

AbstractHydrolysis of synthetic triglycerides by rattlesnake and leopard shark pancreatic enzymes revealed striking differences in specificity, depending on the presence or absence of sodium taurocholate. Without added sodium taurocholate the classical specificity of pancreatic lipase was expressed. Rattlesnake enzymes, in the presence of sodium taurocholate, attacked the unsaturated oleic acid in the 2‐position of racemic glycerol‐1‐palmitate‐2‐oleate‐3‐stearate nearly twice as fast as either outside saturated fatty acid. In this instance, over 90% of the monoglyceride which accumulated were 1‐monoglyceride. These results are attributed to very high levels of bile salt activated nonspecific lipase. Eight vertebrate species were compared. With the exception of the rattlesnake and leopard shark, the other species (3 elasmobranchs and 3 mammals) all exhibited low levels of non‐specific lipase, e.g. less than 5% hydrolysis of the 2‐position of racemic glycerol‐1‐palmitate‐2‐oleate‐3‐stearate in the presence of sodium taurocholate.
Bile acid metabolism in mammals: IX. Conversion of chenodeoxycholic acid to cholic acid by isolated perfused rat liver
Authors: Yousef I. M. , Fisher M. M. 
Published: November 2006

AbstractCurrent dogma of bile acid synthesis in mammals insits that hydroxylation of the ring structure at C‐12 precedes side chain oxidation, and that chenodeoxycholic acid is not converted to cholic acid under normal conditions. This report concerns the conversion of chenodeoxycholic acid to cholic acid by isolated, perfused rat liver. Results indicate that isolated perfused rat liver has a definite, but limited, capacity for synthesis of cholic acid from chenodeoxycholic acid.
Metabolism of linolenic acid in developing brain: I. Incorporation of radioactivity from 1‐14C linolenic acid into brain fatty acids
Authors: Dhopeshwarkar Govind A. , Subramanian Carole 
Published: November 2006

AbstractTwelve‐thirteen day old rats were given 1‐14C linolenic acid by intraperitoneal injection. Fatty acids were isolated from the brains of animals sacrificed at the end of 8 and 48 hr and 15 and 45 days. Eight hr after the tracer, radioactivity was found neither in 18∶3 nor its endproduct, 22∶6, and palmitate was the most highly radioactive component. At longer intervals, 22∶6 seemed to retain much of the radioactivity, whereas palmitate showed a precipitous decline in radioactivity. Initial oxidation of linolenate and sparing of the linolenate complexed with polar lipids are discussed.