bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dietary regulation of phosphatidic acid synthesis from dihydroxyacetone phosphate and fatty acid by rat liver microsomes
Authors: Rao G. Ananda , Sorrels M. F. , Reiser R. 
Published: November 2006

AbstractPhosphatidic acid synthesis from dihydroxyacetone phosphate and 1‐14C‐palmitate was studied in liver microsomes of rats maintained on a stock diet (5% fat), fasted for three days after being fed the stock diet, or given a high fat diet (15% fat) or a fat free diet for a week after being fed the stock diet. The amounts of phosphatidic acid synthesized per minute per milligram of microsomal protein in rats ingesting a stock diet or a fat free diet were at least twice the levels observed in rats either fasting or maintained on a high fat diet. Following fasting, realimentation with either a fat free or high fat diet returned the microsomal capacity for phosphatidic acid synthesis to approximately the same level, which was higher than that observed in rats maintained on a stock diet. Analogous results were observed when glyceraldehyde 3‐phosphate was used as the glyceride‐glycerol precursor, probably because microsomes convert glyceraldehyde 3‐phosphate to dihydroxy‐acetone phosphate. These studies demonstrate that phosphatidic acid synthesis from dihydroxyacetone phosphate by particulate enzymes is influenced by diet.
The isolation and specificity of alfalfa lipoxygenase
Authors: Chang C. C. , Esselman W. J. , Clagett C. O. 
Published: November 2006

AbstractPartial purification of the lipoxygenase from alfalfa seed was accomplished by fractionation of the protein with (NH4)2SO4, phosphate, heavy metal salts and ultracentrifugation. About 24% of the original activity was recovered. The partially‐purified alfalfa lipoxygenase enzyme was free of hydroperoxide‐decomposing activity and was used to determine the positional specificity of linoleic acid oxidation by alfalfa lipoxygenase. Combined gas liquid chromatography‐mass spectrometry was used to analyze known mixtures of 10‐ and 12‐hydroxystearic acid derivatives and was satisfactory for the quantitative determination of the ratio of each component. This combination was used to analyze mixtures containing position isomers of hydroxy fatty acids without separation of each individual compound by other methods. Hydroperoxides produced from linoleic acid oxidation catalyzed by alfalfa lipoxygenase were converted by sodium borohydride reduction, catalytic hydrogenation and bis(trimethylsilyl)acetamide silylation to their corresponding trimethylsilyl either esters and the positional distribution was studied. The 9‐ and 13‐linoleate hydroperoxides produced by alfalfa lipoxygenase were in equal concentrations (50∶50) whereas the distribution for soybean lipoxygenase was 70% 13‐ and 30% 9‐hydroperoxides.
Studies on the hydrolysis and utilization of long chain acyl CoA thioesters by liver microsomes
Authors: Jezyk Peter F. , Hughes Haywood N. 
Published: November 2006

AbstractAcyl CoA thioester “hydrolase” activity exhibited by liver microsomal preparations using a spectrophotometric assay for released CoA has been shown to be a composite of several enzymatic reactions. Pig liver microsomes form a considerable amount of triacylglycerol from endogenous precursors, with essentially all acyl groups being incorporated into the 1,3 positions. Rat and rabbit liver microsomes form very little triacylglycerol under the same conditions. The true acyl CoA hydrolase activity of pig liver microsomes is relatively insensitive to diisopropylfluorophosphate (DFP), whereas this compound strongly inhibits the rat and rabbit enzymes. The hydrolase remaining in the liver microsomes after DFP treatment is rapidly inactivated when incubated in the presence of substrate.
The inhibitive effects of azasterols on sterol metabolism and growth and development in insects with special reference to the tobacco hornworm
Authors: Svoboda J. A. , Robbins W. E. 
Published: November 2006

AbstractSeveral monoazasterols were found to be potent inhibitors of Δ24‐ and Δ22,24‐ reductase enzyme(s) in the tobacco hornworm,Manduca sexta (Johannson). Certain of these inhibitors also prevented normal larval development and pupation in the hornworm at dietary concentrations in the parts per million range. Comparative studies with several different insects indicated differences between the species with respect to the effects of the azasterols. The relationship of azasterol structure to the inhibitory effect(s) on sterol metabolism and larval development is discussed.
The distribution of sterols in algae
Authors: Patterson Glenn W. 
Published: November 2006

AbstractAvailable analytical techniques are now sufficient for the separation and identification of sterols from complex mixtures in plants. Gas and thin layer chromatography and mass spectroscopy in particular, have been used to resolve some of the confusion concerning the sterol composition of algae. Red algae (Rhodophyta) contain primarily cholesterol, although several species contain large amounts of desmosterol, and one species contains primarily 22‐dehydrocholesterol. Only a few Rhodophyta contain traces of C‐28 and C‐29 sterols. Fucosterol is the dominant sterol of brown algae (Phaeophyta), apparently the major sterol of every species examined. Most Phaeophyta also contain traces of cholesterol and biosynthetic precursors of fucosterol. The sterols of green algae (Chlorophyta) are much more varied and complex than those of other groups of algae. Whereas the Phaeophyta and Rhodophyta contain one primary sterol, many of the Chlorophyta contain a complex mixture of sterols such as occurs in higher plants. The Chlorophyta contain such sterols as chondrillasterol, poriferasterol, 28‐isofucosterol, ergosterol, cholesterol and others. Sterol composition may be of value in the systematics of plants such as the Chlorophyta. Recently (for the first time) complex mixtures of sterols have been isolated in very small amounts in the blue‐green algae (Cyanophyta). Available data on the sterols of other groups of algae are insufficient for making useful comparisons.
Some pathways and mechanisms in lanosterol‐cholesterol conversion in mammalian tissues
Authors: Paoletti R. , Galli G. , Paoletti E. Grossi , Fiecchi A. , Scala A. 
Published: November 2006

AbstractSterol precursors of cholesterol with a double bond in the lateral chain are present in normal human brain and glioblastoma. Biosynthetic experiments with labeled mevalonate show that the unsaturated intermediates are preferentially labeled when compared with the corresponding saturated sterols. The biological role of sterols containing an 8(14) double bond is discussed.
Hepatotoxicity and lipid metabolism‐IV structure and molecular species of hepatic triglyceride in rats treated with carbon tetrachloride
Authors: Sugano Michihiro , Imaizumi Katsumi , Cho Shuji , Wada Masafuto 
Published: November 2006

AbstractEffects of carbon tetrachloride (CCl4) on the positional distribution of fatty acids and on the molecular species of hepatic triglyceride in female rats were studied. Six hours after a dose of CCl4, the percentages of palmitic and oleic acids were increased at the 1 and 2 positions respectively in comparison to the control, while linoleic acid was decreased at the 3‐position. These changes were not remarkable 20 hr after CCl4. CCl4 treatment generally caused increases in less unsaturated species of triglycerides (S2M, SM2 and S2D) and decreases in more unsaturated species (SD2 and more polyunsaturated). These data suggest that CCl4 induces specific alteration in the metabolism of triglycerides in the liver.
Quantitative determination of glycerol, mono‐ and diglycerides by gas liquid chromatography
Authors: Blum Jaime , Koehler Walter R. 
Published: November 2006

AbstractStandard chemical procedures for the determination of glycerol, mono‐ and diglycerides in food products are lengthy, particularly when more than one component has to be determined in the same sample. Gaschromatographic techniques are applicable to these compounds when they are converted into their trimethylsilyl derivatives. A simple, rapid and quantitative gas chromatographic procedure has now been developed which is based on the addition of an internal standard (cholesteryl acetate) to samples which are subsequently silylated. This procedure has been applied to the direct determination of glycerol, mono‐ and diglycerides in emulsifiers, shortenings and other samples.
Cerebrosides of rabbit and pigeon aorta: Isolation and fatty acid distribution
Authors: Tao Robert V. P. , Foote J. Lindsley 
Published: November 2006

AbstractQuantitative determinations have been made on the cerebrosides isolated from aortas of cholesterol‐fed and normal rabbits, and mature and young pigeons. The fatty acid distributions of these cerebrosides were determined. Cerebroside concentration was higher in pigeons than in rabbits and higher in the animals expected to have atherosclerosis. Comparing supposedly atherosclerotic animals to normal animals, the atherosclerotic animals generally had more unsaturated fatty acids and more 18:0 and 18:1 as compared to 16:0 and 16:1. These trends are consistent with fatty acid data from human aorta. Pigeon data were more similar to human data than were the rabbit data.
Fatty acid metabolism inDrosophila melanogaster: II. Metabolic origin of monoenes
Authors: Kiyomoto R. K. , Keith A. D. 
Published: November 2006

AbstractEvidence is presented thatDrosophilalarvae produce monounsaturated fatty acids by two independent pathways. One of these pathways, involving the direct desaturation of long chain precursors, is sensitive to inhibition by linoleate. The other pathway is resistant to linoleate inhibition and probably has tetradecnoate‐Δ5cisand tetradecnoate‐Δ7cisas intermediates in the synthesis of palmitoleate and oleate, respectively. The use of radioactive precursors of varying chain length and labeled at different positions in the carbon chains provided evidence for the isolation and structure of intermediates involved in the linoleate resistant pathway.
Effect of fructose on rat lipids
Authors: Hill P. 
Published: November 2006

AbstractYoung and mature albino rats were fed Purina chow with and without fructose in the drinking water, and the lipid contents in the serum and livers were determined. Fructose elevated the serum triglyceride and caused an accumulation after 24 hr of liver triglyceride in fed but not fasted mature rats. In young male rats, the liver triglyceride was increased initially but was not found after 10 days. Serum phospholipids were increased in young and mature rats; the content and specific activity of the high density (HD)‐lipoproteins being increased in young rats. In vivo incorporation of labeled acetate into liver cholesterol was reduced. Results suggest that fructose or triglyceride metabolism, or both, in rats differ with age.
Inhibition of renal cortical Rb+ transport by phospholipase C and its relationship to (Na++K+)‐adenosine triphosphatase
Authors: Malila Amra , Masoro Edward J. 
Published: November 2006

AbstractTreatment of isolated renal cortical tubules with a low concentration of phospholipase C (one which does not lead to a chemically detectable loss of tubular phospholipid) results in a markedly inhibited Rb+ transport function which is referable to the loss of a phospholipid component of the tubules. This treatment also results in an inhibition of the (Na++K+)‐adenosine triphosphatase enzyme of the tubules. The data are consistent with the concept that it is the loss in (Na++K+)‐adenosine triphosphatase activity which is responsible for phospholipase C‐induced inhibition of Rb+ transport.
Liberation of aldehydes from alk‐1‐enyl glyceryl ethers by acid hydrolysis
Authors: Wood Randall , Healy Kathleen 
Published: November 2006

AbstractLabeled alk‐1‐enyl glyceryl ethers were used in conjunction with thin layer chromatography to study the liberation of aldehydes from alk‐1‐enyl glyceryl ethers by two acid hydrolysis procedures. Both methods gave similar results, but neither liberated the aldehydes quantitatively. Only 75–85% of the alk‐1‐enyl glyceryl ether radioactivity was liberated as free aldehydes. Several nonaldehyde products were detected and one appeared to be a cyclic acetal.
The functioning of the lipids and lipoproteins of sarcotubular membranes in calcium transport
Authors: Masoro E. J. , Yu Byung Pal 
Published: November 2006

AbstractIn the intact muscle cell, an internal tubular membrane system called the sarcoplasmic reticulum (SR) plays an important role in the contraction‐relaxation cycle by controlling the Ca++ of the myoplasm; release of Ca++ from the SR to myoplasm initiates contractile activity and sequestring Ca++ in the SR by means of a transport system causes muscle to relax. Fragments of the SR with a vesicular structure can be isolated from muscle homogenate and these vesicles are able to vigorously transport Ca++ from incubation media into the intravesicular space thus enabling study of Ca++ transport under precisely defined in vitro conditions. A highly purified fraction of SR vesicles called SF1 were prepared from rat muscle by means of density gradient centrifugation procedures. The role of SR lipid in Ca++ transport was studied. SF1 was treated in vitro with either phospholipase A or C or D or polyene antibiotics. The effect of essential fatty acid deficiency, induced in vivo, was also investigated. It was concluded that the only structural feature of SF1‐lipid involved in Ca++ transport and the associated adenosine triphosphatase is the phosphoryl moiety of the phospholipids. Evidence was obtained which inplicated histidine residues of the SF1 protein in this transport function. To study the role of SF1 protein in this process in depth, the membranes were solubilized by a sodium dodecylsulfate system and made free of their lipid components. More than 95% of this protein is soluble in dilute salt solution; of this, more than 90% is composed of a protein fraction which can be isolated by gel filtration (called protein fraction‐2). Protein fraction‐2 contains large molecular aggregates of small polypeptide subunits of identical or nearly identical molecular weight. They contain solely N‐terminal glycine and probably only C‐terminal alanine. The significance of such a high percentage of similar polypeptide subunits in SR is discussed.
Serum lipid transport systems: Recent advances
Authors: Lopez‐S Alfredo 
Published: November 2006

AbstractLipids circulating in the plasma are transported in water soluble form as lipid‐protein complexes. Lipoproteins can be classified according to size, density, electrophoretic mobility and protein composition. The ability of low density lipoproteins and very low density lipoproteins (VLDL) to form complexes with different polyanions has been also used as a method for separation and study of serum lipoproteins. Even within classes of lipoproteins closely related otherwise, the amount of different lipids and their ratios to each other and to protein are variable. Two enzymatic systems seem to be at least partly responsible for the different lipid compositions of serum lipoproteins: lipoprotein lipase and lecithin‐cholesterol acyltransferase (LCAT). LCAT, which seems to be associated with α‐lipoproteins, is responsible for the formation of the bulk of cholesteryl‐esters in human serum. Changes in activity of this enzyme may explain the observed changes with age and disease of serum cholesteryl‐ester fatty acids (CEFA). Differences in CEFA pattern are found between newborn and adult animals, including man. The activity of serum LCAT was observed to increase with age in animals and to decrease markedly in patients with liver cirrhosis. These patients show abnormal serum CEFA patterns and abnormally low proportions of pre‐β‐ (VLDL) and α‐ (high density) lipoproteins.
Studies on the role of phospholipids in the triglyceride cycle: III. Liver and plasma phospholipid exchange in depancreatized dogs
Authors: Olmsted C. A. 
Published: November 2006

AbstractLipid mobilization from the liver to extrahepatic sites of utilization and to adipose tissue for storage and recycling via the triglyceride cycle requires de novo synthesis of liver lecithins. The role of liver phospholipid (PL) synthesis and plasma phospholipid turnover has been studied under a number of conditions which appear to relate liver lipoprotein formation and release to liver PL synthesis and transport. Conditions which enhance nonesterified fatty acid (NEFA) release from adipose tissue or which inhibit liver PL synthesis prompt liver lipid accumulation. Lipid accumulates in the liver principally as triglyceride when any one of a number of factors required for liver lipoprotein comple formation is blocked, such as by ethionine, or when NEFA release to plasma is increased, such as in cold acclimatization. The relationship of liver PL to liver lipid transport is shown also following recovery from these conditions. Recovery from liver triglyceride (TG) accumulation is accompanied by increased PL synthesis, remobilization of liver PL, and increased turnover of plasma phospholipids. The relative specific activity (RSA) of phospholipid phosphorus (SA of plasma to liver PLP) is increased in depancreatized dogs during liver lipid accumulation. Following the initial depression in liver PL synthesis and transport caused by ethionine administration the RSA increased in all animals studied, indicating a remobilization of the accumulated TG. This remobilization of liver lipid occurs to a greater extent in depancreatized dogs than in normal dogs under the same conditions.
The phospholipids of corynebacteria
Authors: Brennan Patrick J. , Lehane Derek P. 
Published: November 2006

AbstractThe phospholipids ofCorynebacterium diphtheriae, Corynebacterium xerosis, Corynebacterium equi andCorynebacterium ovis were examined, largely by chromatographic procedures. In all of these, lipids of the phosphoinositide and mannophosphoinositide type were prominent. In contrast to the mycobacteria, the mannophosphoinositides of the corynebacteria were all dimannophosphoinositides; however, as in mycobacteria, these dimannophosphoinositides apparently occurred in the diacylated and triacylated forms—the tetraacylated component prominent in mycobacteria was absent. Phosphatidylethanolamine and phosphatidylserine were also absent. InCorynebacterium diphtheriae the major single phospholipid corresponded to phosphatidylglycerol: cardiolipin also appeared to be a major lipid. The fatty acids of the corynebacterial phospholipids were distinguished by the presence of branched chain isomers of medium chain length. The importance of phospholipids in the taxonomy of the actinomycetes and related eubacteria is discussed.
Quantitative analysis of the phospholipids of some marine bioluminescent bacteria
Authors: Eberhard Anatol , Rouser George 
Published: November 2006

AbstractQuantitative analyses of the phospholipids of three strains of marine bioluminescent bacteria were carried out after separation by two‐dimensional thin layer chromatography. The phospholipids of all three species consisted of about 75% phosphatidyl ethanolamine, 13% phosphatidyl glycerol and 7% cardiolipin. The composition was only slightly affected by drastic changes in the growth conditions. One of the species contained poly‐β‐hydroxybutyrate. The fatty acids of another species contained principally straight and branched‐chain 16 and 18 carbon fatty acids. No clue as to the nature of the elusive “aldehyde factor” of bacterial bioluminescence was found by analysis of aldehyde deficient mutants, indicating that possibly the factor is not a major phospholipid of these bacteria.
Effects of level and type of dietary fat on incidence of mammary tumors induced in female sprague‐dawley rats by 7,12‐dimethylbenz(α) anthracene
Authors: Carroll K. K. , Khor H. T. 
Published: November 2006

AbstractFemale Sprague‐Dawley rats on semisynthetic diets containing 10% and 20% by weight of corn oil developed more mammary adenocarcinomas after treatment with a single oral dose of 7,12‐dimethylbenz(α)anthracene than similar rats on diets containing only 0.5% or 5% corn oil. Experiments with 10 different fats and oils fed at the 20% level indicated that unsaturated fats enhance the yield of adenocarcinomas more than saturated fats. Fibroadenomas and adenomas were also found in small numbers in all dietary groups but the yield did not seem to be influenced by level or type of dietary fat. The possible relevance of these findings to the incidence of breast cancer in humans is discussed.
The infrared spectra and polymorphism of long chain esters: IV. Some esters from tetradecanol, hexadecanol, octadecanol, eicosanol, docosanol and dodecanoic, tetradecanoic, hexadecanoic, octadecanoic and eicosanoic acid
Authors: Aleby S. , Fischmeister I. , Iyengar B. T. R. 
Published: November 2006

AbstractInfrared spectra and x‐ray diffraction photographs have been recorded for some normal‐chain esters of long chain acids and long chain alcohols. The substances show no polymorphism but two different structure types exist, one with the chains tilting towards the end group planes and one with vertical chains. The IR spectra permit determination of the chain length of the acid methylene chain. The length of the alcohol chain cannot be deduced.
A possible block in the intermediary metabolism of glucose into proteins and lipids in the brains of undernourished rats
Authors: Agrawal H. C. , Fishman M. A. , Prensky A. L. 
Published: November 2006

Abstract[U‐14C] Glucose or [1‐14C] L‐leucine was injected intraperitoneally into 28‐day‐old undernourished rats and control sibs who were killed 6 hr later. Brain proteins and lipids were extracted and the lipids fractionated by silicic acid column chromatography into cholesterol, glycolipids and phospholipids. The specific activity of labeled carbon derived from [U‐14C] glucose in brain proteins was reduced by 25% in undernourished animals when compared to controls. A similar reduction was seen in the specific activity of brain lipids of undernourished animals: 14% for cholesterol, 21% for phospholipids and 35% for glycolipids. When [1‐14C] l‐leucine was used as a direct precursor of brain protein synthesis, the specific activity in the undernourished group was only 5% less than that found for the controls. This was not statistically significant. The results suggest that there may be a block in the intermediary metabolism of glucose in the brains of undernourished rats that reduces the availability of glucose carbon to the precursor pool used for protein and lipid synthesis.
The labeling of brain ethanolamine phosphoglycerides from cytidine diphosphate ethanolamine in vitro
Authors: Porcellati G. , Biasion M. G. , Pirotta M. 
Published: November 2006

AbstractChicken brain microsomes convert14C‐ethanolamine‐labeled cytidine diphosphate ethanolamine (CDPE) to ethanolamine lipids (EPG) at a measurable rate. Mitochondria and particle‐free supernatant fractions are almost inactive. On adding saturating amounts of diacyl glycerol to the microsomes, formation of EPG increases 10‐fold, and is almost totally confined to the diacylsn‐glycero‐3‐phosphorylethanolamine (GPE), whose synthesis increases 20‐fold (from 13.1 to 249 mμmoles/mg protein/hr). The addition of the 1‐alkenyl 2‐acyl glycerol also produces a noticeable increase in the rate of EPG labeling, which is almost exclusively confined to the alkenyl acyl GPE, whose synthesis is stimulated 30‐fold (from 3.1 to 90 mμmoles/mg protein/hr). Synthesis of alkyl acyl GPE from CDPE was not detected in the brain microsomes. Synthesis of EPG from CDPE by chicken brain homogenates has also been examined and results similar to those reported for the brain microsomes were obtained. In addition, small amounts of labeled alkyl acyl GPE are produced from CDPE in the homogenates, but in no case does this synthesis increase on adding various lipid acceptors to the incubation system. Various properties of the phosphorylethanolaminediacyl glycerol phosphotransferase (E.C. 2.7.8.1) of brain microsomes were examined. It is concluded that the enzymic activities which convert CDPE to diacyl GPE and alkenyl acyl GPE, respectively, are similar.