bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface components of chylomicrons from rats fed glyceryl or alkyl esters of fatty acids: Minor components
Authors: Yang L. Y. , Kuksis A. , Myher J. J. , Pang H. 
Published: November 2006

AbstractThe lipid class, fatty acid and molecular species composition of the minor polar surface components of rat lymph chylomicrons were determined during absorption of menhaden oil and corn oil or of the corresponding fatty acid ethyl esters. In addition to the previously reported minor polar lipids (sphingomyelin, phosphatidylserine, phosphatidylinositol, phosphatidic acid and lysophosphatidylcholine), we identified phosphatidylglycerol, dimethyl‐phosphatidylethanolamine, ceramide and cholesteryl sulfate in the chylomicrons from both oil and ester feeding. The dietary fatty acids were found to be incorporated to a variable extent into the different phospholipid classes, the proportions of which remained the same during both types of feeding. No evidence was obtained for the presence of the minor glycerophospholipids characteristic of the lysosomal membranes (e.g., bis‐phosphatidic, lysobisphosphatidic and semilysobis‐phosphatidic acids), although special efforts were made to identify them. These results indicate that the chylomicrons arising from the monoacylglycerol and phosphatidic acid pathways of triacylglycerol biosynthesis become enveloped in closely similar monolayers of phospholipids. Hence, all triacylglycerols may be secreted from the villus cellsvia a common mechanism as suggested by the previously demonstrated convergence (at the 2‐monoacylglycerol stage) of the monoacylglycerol and the phosphatidic acid pathways of mucosal triacylglycerol formation [Yang, Y.L., and Kuksis, A. (1991)J. Lipid Res. 32, 1173–1186].
Effects of dietary saturated fat on erucic acid induced myocardial lipidosis in rats
Authors: Kramer J. K. G. , Sauer F. D. , Wolynetz M. S. , Farnworth E. R. , Johnston K. M. 
Published: November 2006

AbstractMale Sprague‐Dawley rats were fed for one week diets containing 20% by weight fat/oil mixtures with different levels of erucic acid (22∶1n−9) (∼2.5 or 9%) and total saturated fatty acids (∼8 or 35%). Corn oil and high erucic acid rapeseed (HEAR) oil were fed as controls. The same hearts were evaluated histologically using oil red O staining and chemically for cardiac triacylglycerol (TAG) and 22∶1n−9 content in cardiac TAG to compare the three methods for assessing lipid accumulation in rat hearts. Rats fed corn oil showed trace myocardial lipidosis by staining, and a cardiac TAG content of 3.6 mg/g wet weight in the absence of dietary 22∶1n−9. An increase in dietary 22∶1n−9 resulted in significantly increased myocardial lipidosis as assessed histologically and by an accumulation of 22∶1n−9 in heart lipids; there was no increase in cardiac TAG except when HEAR oil was fed. An increase in saturated fatty acids showed no changes in myocardial lipid content assessed histologically, the content of cardiac TAG or the 22∶1n−9 content of TAG at either 2.5 or 9% dietary 22∶1n−9. The histological staining method was more significantly correlated to 22∶1n−9 in cardiac TAG (r=0.49;P<0.001) than to total cardiac TAG (r=0.40;P<0.05). The 22∶1n−9 content was highest in cardiac TAG and free fatty acids. Among the cardiac phospholipids, the highest incorporation was observed into phosphatidylserine, followed by sphingomyelin. With the addition of saturated fat, the fatty acid composition showed decreased accumulation of 22∶1n−9 and increased levels of arachidonic and docosahexaenoic acids in most cardiac phospholipids, despite decreased dietary concentrations of their precursor fatty acids, linoleic and linolenic acids.
Comparison of sulfoquinovosyl diacylglycerol from spinach and the purple bacteriumRhodobacter sphaeroides by fast atom bombardment tandem mass spectrometry
Authors: Gage Douglas A. , Huang Zhi‐Heng , Benning Christoph 
Published: November 2006

AbstractIsolated sulfoquinovosyl‐diacylglycerol (SQD) from spinach and the purple bacteriumRhodobacter sphaeroides provide two sources of very different molecular species of SQD. We were able to demonstrate by fast atom bombardment‐collisionally activated dissociation tandem mass spectrometry in the negative ion mode that the sulfoquinovosyl head group of the plant and bacterial lipids can be characterized by the common fragmentation pattern found in the spectra of both samples. Differences in the acyl functions from the two sources were also identified by this technique. SQD specific fragments are found atm/z 299, 283, 241, 225, 165 and 80 which indicate the presence of the sulfoquinovosyl moiety. The two predominant molecular species found in spinach contain palmitic and linolenic ([M−H]− atm/z 815) or two linolenic acids ([M−H]− atm/z 837) in thesn−1 andsn−2 positions, while the two major species of the bacterial lipid contain palmitic and 18∶1 (vaccenic) cids ([M−H]− atm/z 819) or stearic and 18∶1 (vaccenic) acids, ([M−H]− atm/z 847), respectively.
The fatty acids of the spongeDysidea fragilis from the black sea
Authors: Christie W. W. , Brechany Elizabeth Y. , Stefanov K. , Popov S. 
Published: November 2006

AbstractThe fatty acid composition of the sponge,Dysidea fragilis, from the Black Sea has been determined by analytical gas chromatography, silver ion high‐performance liquid chromatography and gas chromatography/mass spectrometry. More than a hundred different fatty acids were identified, of which many were similar to those in sponges from tropical seas. On the other hand, some of the fatty acids identified have not been found previously in sponges or other marine sources and perhaps are new to science. These include 13‐methyl‐tetradec‐4‐enoic and 14‐methyl‐hexadec‐6‐enoic acids, together with demospongic acids,i.e. 5,9,17‐tetracosatrienoic, 5,9,17‐pentacosatrienoic and 5,9,19‐pentacosatrienoic acids. From the elution behavior on silver nitrate chromatography, all the double bonds were of thecis‐configuration.
Linoleic acid metabolism in the red algaLithothamnion corallioides: Biosynthesis of 11(R)‐hydroxy‐9(Z),12(Z)‐octadecadienoic acid
Authors: Hámberg Mats , Gerwick William H. , Åsen Per Arvid 
Published: November 2006

AbstractIncubation of [1‐14C]linoleic acid with an enzyme preparation obtained from the red algaLithothamnion corallioidesCrouan resulted in the formation of 11‐hydroxy‐9(Z),12(Z)‐octadecadienoic acid as well as smaller amounts of 9‐hydroxy‐10(E),12(Z)‐octadecadienoic acid, 13‐hydroxy‐9(Z),11(E)‐octadecadienoic acid and 11‐keto‐9(Z),12(Z)‐octadecadienoic acid. Steric analysis showed that the 11‐hydroxyoctadecadienoic acid had the (R) configuration. The 9‐ and 13‐hydroxyoctadecadienoic acids were not optically pure, but were due to mixtures of 75% (R) and 25% (S) enantiomers (9‐hydroxyoctadecadienoate), and 24% (R) and 76% (S) enantiomers (13‐hydroxy‐octadecadienoate). 11‐Hydroxyoctadecadienoic acid was unstable at acidic pH. In acidified water, equal parts of 9(R,S)‐hydroxy‐10(E),12(Z)‐octadecadienoate and 13(R,S)‐hydroxy‐9(Z),11(E)‐octadecadienoate, plus smaller amounts of the corresponding (E),(E) isomers were produced. In aprotic solvents, acid treatment resulted in dehydration and in the formation of equal amounts of 8,10,12‐ and 9,11,13‐octadecatrienoates. The enzymatic conversion of linoleic acid into the hydroxyoctadecadienoic acids and the ketooctadecadienoic acid was oxygen‐dependent; however, inhibitor experiments indicated that neither lipoxygenase nor cytochrome P‐450 were involved in the conversion. This conclusion was supported by experiments with18O2 and H218O, which demonstrated that the hydroxyl oxygen of the hydroxy‐octadecadienoic acids and the keto oxygen of the 11‐ketooctadecadienoic acid were derived from water and not from molecular oxygen.
Metabolism of [1‐14C]docosahexaenoate (22∶6n−3), [1‐14C]eicosapentaenoate (20∶5n−3) and [1‐14C]linolenate (18∶3n−3) in brain cells from juvenile turbotScophthalmus maximus
Authors: Tocher Douglas R. , Mourente Gabriel , Sargent John R. 
Published: November 2006

AbstractThe incorporation of [1‐14C]18∶3n−3, (LNA) and [1‐14C]‐22∶6n−3 (DHA), and the metabolismvia the desaturase/elongase pathways of [1‐14C]LNA, and [1‐14C]20∶5n−3 (EPA) were studied in brain cells from newly‐weaned (1‐month‐old) and 4‐month‐old turbot. The rank order of the extent of net incorporation of both LNA and DHA into glycerophospholipids was total diradyl glycerophosphocholines (CPL)> total diradyl glycerophosphoethanolamines (EPL)> phosphatidylserine (PS) and phosphatidylinositol (PI) and was independent of the polyunsaturated fatty acid added, the age of the fish and the time of incubation. However, the rate of incorporation of LNA into total lipid, CPL, EPL and PS was significantly greater than the rate of incorporation of DHA, and there was a significantly greater amount of DHA incorporated into EPL than LNA. There was no significant difference between the amounts of LNA and DHA incorporated into total lipid, CPL, PS and PI. Therefore, little preferential uptake and incorporation of DHA into brain cells was apparent. In 24‐h incubations, on average 1.1% and 8.5% of radioactivity from [1‐14C]LNA and [1‐14C]EPA, respectively, were recovered in the DHA fraction. Therefore, LNA cannot contribute significantly to brain DHA levels in the turbot but EPA can. There were no significant differences between the amounts of radioactivity from either [1‐14C]LNA or [1‐14C]EPA recovered in the individual products/intermediates of the desaturase pathways in brain cells from 30‐day‐old and 120‐day‐old turbot.
Phospholipid fatty acyl distribution of three fungi indicates positional specificity for n‐6vs. n‐3 fatty acids
Authors: Kendrick Andrew , Ratledge Collin 
Published: November 2006

AbstractPhospholipids of the fungiConidobolus nanodes, Entomophthora exitalis andSaprolegnia parasitica were extracted and analyzed. The phospholipid content was the same (2.4%) for the three species and was independent of the total lipid content. Phospholipase A2 degradation of individual phospholipid classes showed an asymmetrical distribution of polyunsaturated fatty acids (PUFA) between the two fatty acyl positions of glycerol. There was a predominance of n‐6 PUFA at position 2 and a predominance of n‐3 PUFA at position 1. WithC. nanodes andE. exitalis, 20∶5n−3 is derived from 18∶3n−3 and is located predominantly at position 1. InS. parasitica 20∶5n−3 is synthesized from 18∶3n−6via 20∶4n−6 and is located predominantly at position 2. It is suggested that the asymmetrical distribution of PUFA between positions 1 and 2 of glycerol Points towards different sites of synthesis of the two classes of PUFA, and that cross‐over between PUFA of the different types is prevented by thesn‐1 orsn‐2 positional specificity of the desaturases.
Nonesterified fatty acids in normal and diabetic rat sciatic nerve
Authors: Chattopadhyay Jyotiprakas , Thompson Ed W. , Schmid Harald H. O. 
Published: November 2006

AbstractAlloxan‐induced diabetes in rats results in elevated levels of nonesterified fatty acids (NEFA) in whole sciatic nerve and its endoneurium. Increases in NEFA levels are more pronounced in whole diabetic nerve (40% over control) than in its endoneurial portion (20–30%). Alterations in the composition of phospholipid fatty acids are observed as well, including an increase in linoleate (18∶2n−6) in endoneurial phosphatidylethanolamine and a decrease in arachidonate (20∶4n−6) in both phosphatidylethanolamine and phosphatidylinositol of diabetic nerve.
Changes in fatty acid composition of plasma and oviduct lipids during sexual maturation of Japanese quail
Authors: Pageaux Jean François , Joulain Catherine , Fayard Jean Michel , Lagarde Michel , Laugier Christian 
Published: November 2006

AbstractThe fatty acid (FA) compositions of plasma and oviduct phospholipids (PL) and triglycerides (TG) were studied throughout the natural sexual development of the Japanese quail. In the oviduct, PL concentration increased rapidly during the period of active oviduct cell proliferation and then remained at a constant level during the phase of cellular hypertrophy. Oviduct and plasma TG concentrations were 2‐ and 10‐fold higher, respectively, in fully developed animals than in immature ones. During natural sexual maturation of the quail, the FA compositions of PL and TG were markedly modified both in plasma and in oviduct. These qualitative changes occurred predominantly during the period of intense cellular proliferation of oviduct cells, and also were observed in immature animals injected with physiological doses of estradiol. In oviduct PL, the proportions of 20∶4n−6 and 22∶4n−6 decreased significantly (from 20 to 10% and 3.5 to 0.7%, respectively) whereas those of 18∶2n−6 increased (from 8.5 to 21%). In contrast, the plasma PL proportions of 20∶4n−6, 22∶4n−6 and 18∶2n−6 were decreased significantly and the percentage of 18∶1n−9 doubled, suggesting that the oviduct is able to utilize certain plasma FA to a greater extent than others. Changes in plasma and oviduct lipid composition occurring in the quail during sexual development may be attributed to estradiol, which stimulates hepatic Δ9 desaturase and inhibits the oviduct Δ6 desaturase. The changes in FA composition observed in oviduct phospholipids are discussed in relation to eicosanoid production and cellular proliferation.
The effect of beta blocking drugs on lipid peroxidation in rat heartin vitro
Authors: Jenkins R. R. , Del Signore C. M. , Sauer P. , Skelly C. 
Published: November 2006

AbstractBeta‐adrenergic receptor blocking drugs include a structurally related class of drugs that are employed clinically to treat a variety of cardiovascular disorders. Since these drugs exert additional nonspecific effects including membrane stabilization, representative samples including atenolol, dilevolol, labetolol, metoprolol and propranolol were studied to determine their influence on lipid peroxidation. Homogenates or liposomes of adult rat hearts were incubated in the presence of various concentrations of propranolol or equivalent concentrations of dilevolol, labetolol, metoprolol or atenolol. Lipid peroxidation was stimulated with 50 μM FeSO4, 5 μMt‐butyl hydroperoxide (homogenates) or 0.2 mM citrate FeSO4 (liposomes) plus O2. Lipid peroxidation, as assessed by both the thiobarbituric acid reaction and chemiluminescence, was reduced in a dose‐dependent manner as the propranolol concentration was increased from 1 to 10 mM. The five beta‐adrenergic receptor blocking drugs reduced lipid peroxidation both in crude homogenates and in liposomes; their effectiveness was related to their lipophilicity. Dilevolol, propranolol, labetolol and metoprolol at a concentration of 20 mM reduced lipid peroxidation by 45%, 37%, 35% and 28%, respectively. The hydrophilic blocker atenolol was ineffective in reducing lipid peroxidation event at elevated concentrations. Lipophilic beta‐blocking drugs apparently are capable of exerting an antioxidant effect in protecting membrane lipids against peroxidation.
Ascorbate and phenolic antioxidant interactions in prevention of liposomal oxidation
Authors: Thomas Craig E. , McLean Larry R. , Parker Roger A. , Ohlweiler David F. 
Published: November 2006

AbstractEfficient prevention of membrane lipid peroxidation by vitamin E (α‐tocopherol) may involve its regeneration by vitamin C (ascorbate). Conceivably, the efficacy of antioxidants designed as therapeutic agents could be enhanced if a similar regeneration were favorable; thus, a model membrane system was developed which allowed assessment of interaction of phenolic antioxidants with ascorbate and ascorbyl‐6‐palmitate. Ascorbate alone (50–200 μM) potentiated oxidation of soybean phosphatidylcholine liposomes by Fe2+/histidine‐Fe3+, an effect which was temporally related to reduction of Fe3+ generated during oxidation. Addition of 200 μM ascorbate to α‐tocopherol‐containing liposomes (0.1 mol%) resulted in marked, synergistic protection. Accordingly, in the presence but not absence of ascorbate, α‐tocopherol levels were maintained relatively constant during Fe2+/histidine‐Fe3+ exposure. Probucol (4,4′‐[(1‐methylethylidine)bis(thio)]bis[2,6‐bis(1,1‐dimethylethyl)]phenol), and antioxidant which prevents oxidation of low density lipoproteins, and its analogues MDL 27,968 (4,4′‐[(1‐methylethylidene)bis(thio)]‐bis[2,6‐dimethyl]phenol) and MDL 28,881 (2,6‐bis(1,1‐dimethylethyl)‐4‐[(3,7,11‐trimethyldodecyl)thio]phenol) prevented oxidation but exhibited no synergy with ascorbate. Ascorbyl‐6‐palmitate itself was an effective antioxidant but did not interact synergistically with any of the phenolic antioxidants. Differential scanning calorimetry revealed significant differences among the antioxidants in their effect on the liquid‐crystalline phase transition of dipalmitoyl phosphatidylcholine (DPPC) liposomes. Both α‐tocopherol and MDL 27,968 significantly reduced the phase transition temperature and the enthalpy of the transition. MDL 28,881 had no effect while probucol was intermediate. The potential for ascorbate or its analogues to interact with phenolic antioxidants to provide a more effective antioxidant system appears to be dictated by structural features and by the location of the antioxidants in the membrane.
The determination of tissue ethanolamine levels by reverse‐phase high‐performance liquid chromatography
Authors: McMaster Christopher R. , Choy Patrick C. 
Published: November 2006

AbstractA rapid and sensitive procedure for the determination of ethanolamine levels in mammalian tissues is reported. Ethanolamine was extracted from the tissue with a chloroform/methanol mixture, followed by phase separation. The aqueous phase was subjected to charcoal chromatography and the lluant was derivatized with phenylisothiocyanate. The amount of phenylthiocarbamyl (PTC) ethanolamine in the tissue extract was determined by reverse‐phase high‐performance liquid chromatography. Quantitation of PTC ethanolamine was linear between 0.1–10 nmol. The pool sizes of ethanolamine in hamster heart, liver and kidney were found to be 1.07, 0.92 and 1.11 μmol/g wet weight, respectively. The sensitivity of the method would allow the determination of ethanolamine in very small tissue samples.
Catalytic deuteration of alkynols and their tetrahydropyranyl ethers
Authors: Rakoff Henry , Rohwedder William K. 
Published: November 2006

AbstractTo ascertain the effect of a replaceable hydrogen on deuterium incorporation, 2‐pentynol, 2‐hexynol, 3‐hexynol, their tetrahydropyranyl (THP) ethers, and the mono‐ and di‐THP ethers of 3‐hexyne‐1,6‐diol were deuterated catalytically with deuterium gas. The differences in percentd4 (using Wilkinson's catalyst,tris(triphenylphosphine)‐chlororhodium) or percentd2 (using Lindlar's catalyst, Pd on CaCO3 poisoned with a lead salt) measured for the alcohols and their THP ethers were, in general, less than 4% with either catalyst. Noticeable exceptions occurred during the deuteration over Wilkinson's catalyst of 2‐pentynol and 2‐hexynol; extensive scatter resulted in a substantial decrease in percentd4. This scatter was not observed with the corresponding THP ethers.
Effect of dietary fish oil on the rate of very low density lipoprotein triacylglycerol formation and on the metabolism of chylomicrons
Authors: Lottenberg Ana Maria P. , Oliveira Helena C. F. , Nakandakare Edna R. , Quintão Eder C. R. 
Published: November 2006

AbstractThe mechanism by which ω3 fatty acids lower plasma triacylglycerol levels was investigated. Rats were fed fish oil, olive oil (10% fat by weight) or a nonpurified diet 4% fat by weight) for 15 days. Lipoprotein lipase was inhibited by intra‐arterial administration of Triton WR 1339 to estimate hepatic triacylglycerol output. Rats fed the olive oil diet showed a higher rate of triacylglycerol formation than rats fed the ω3 fatty acid diet or the low‐fat diet. All three groups showed identical rates of removal from plasma of intraarterially administered artificial chylomicrons that had simultaneously been labeled with cholesteryl [1‐14C]oleate and [9,10(n)‐3H]triolein. Liver radioactivity and total fat content were lowest in rats fed the fish oil diet, indicating that ω3 fatty acids were preferentially metabolized in liver. Chylomicrons obtained from donor rats fed either fish oil containg [14C]cholesterol or olive oil containing [3H]cholesterol were removed at similar rates when infused together intraarterially into recipient animals. A slower formation of plasma very low density lipoprotein triacylglycerols in rats fed fish oil is probably due to a faster rate of oxidation of the fatty acid chains in the liver resulting in decreased plasma triacylglycerol concentrations.
Effect of dietary fats on some membrane‐bound enzyme activities, membrane lipid composition and fatty acid profiles of rat heart sarcolemma
Authors: Vajreswari A. , Narayanareddy K. 
Published: November 2006

AbstractThe effect of various dietary fats on membrane lipid composition, fatty acid profiles and membrane‐bound enzyme activities of rat cardiac sarcolemma was assessed. Four groups of male weanling Charles Foster Young rats were fed diets containing 20% of groundnut, coconut, safflower or mustard oil for 16 weeks. Cardiac sarcolemma was prepared from each group and the activities of Na+,K+‐ATPase, 5′‐nucleotidase, Ca2+‐ATPase and acetylcholinesterase were examined. ATPase activities were similar in all groups except the one fed coconut oil, which had the highest activities. Acetylcholinesterase activity was also similar in all the groups, however, it was significantly higher in the group fed mustard oil. No significant changes were observed among the groups in 5′‐nucleotidase activity, in the cholesterol‐to‐phospholipid molar ratio and in sialic acid content. The coconut, safflower and mustard oil diets significantly increased cholesterol and phospholipid contents and the lipid‐to‐protein ratio of cardiac sarcolemma as compared to feeding the groundnut oil diet. The fatty acid composition of membrane lipids was quite different among the various groups, reflecting the type of dietary fat given. The total unsaturated‐to‐saturated fatty acid ratio was not different among the various groups; however, the levels of some major fatty acids such as palmitic (16∶0), oleic (18∶1) and linoleic (18∶2) acids were significantly different. Cardiac sarcolemma of the group fed safflower oil had the highest polyunsaturated fatty acid content. The results suggest that dietary fats induce changes not only in the fatty acid composition of the component lipids but also in the activities of sarcolemmal enzymes involved in the regulation of cardiac function.
Lipid composition and mitochondrial respiration in warm‐ and cold‐adapted sea bass
Authors: Trigari Gianni , Pirini Maurizio , Ventrella Vittoria , Pagliarani Alessandra , Trombetti Fabiana , Borgatti Anna Rosa 
Published: November 2006

AbstractThe response to cold of liver and heart membrane lipid composition and mitochondrial respiration in reared sea bass (Dicentrarchus labrax L.) was investigated. Fish acclimation was followed during the natural seasonal cycle from August to March. The data on the fatty acid composition of liver and heart polar lipids and on total lipids of liver mitochondria and microsomes did not indicate any increase in unsaturation in response to cold. The enzyme complexes of the liver and heart mitochondrial respiratory chain showed a repeated negative compensation for cold acclimation. The constancy of the break in the Arrhenius plot of liver cytochrome oxidase (EC 1.9.3.1) was consistent with the lack of homeoviscous adaptation of membrane lipids. A thermoadaptive strategy based on the reduction of sea bass metabolic activity is suggested.