Showing papers in "Lipids in 1984"
TL;DR: Requirements for high levels of (n−3) PUFA in the embryonic and early larval development stages of marine fish are suggested as is a special role for the 20∶4(n−6) in PI.
Abstract: Lipid class analyses and fatty acid analyses of neutral and polar lipids were carried out on ripe roes of herring, cod, haddock, whiting, saithe, sand eel and capelin. Total lipid was 10-26% of roe dry weight. The species with the highest total lipid, sand eel and capelin, also had the highest percentage of neutral lipid in total lipid, 77% and 49% respectively. In the other species, phospholipids accounted for 62-77% of roe total lipid. Both the neutral lipids, and especially the phospholipids, of all species were very unsaturated because of high concentrations of (n-3) polyunsaturated fatty acids (PUFA), frequently amounting to 50% of the total egg lipid. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) had similar fatty acid compositions in all species, with an average ratio (n-3)/(n-6) of ca. 20∶1. Phosphatidylinositol (PI) consistently had high concentrations of 18∶0 and 20∶4 (n-6) with an average ratio of (n-3)/(n-6) of 1.8∶1. Requirements for high levels of (n-3) PUFA in the embryonic and early larval development stages of marine fish are suggested as is a special role for the 20∶4(n-6) in PI.
329 citations
TL;DR: The complete structure of the red crystalline 2∶1 adduct from thiobarbituric acid and malondialdehyde has been unambiguously determined by FTIR and high-field 1H and 13C NMR studies as discussed by the authors.
Abstract: The complete structure of the red crystalline 2∶1 adduct from thiobarbituric acid and malondialdehyde has been unambiguously determined by FTIR and high-field1H and13C NMR studies.
210 citations
TL;DR: Analysis of the oyster fatty acids showed that oysters were able to incorporate some of the dietary14C label into long-chain fatty acids not supplied in the diet, e.g., C20 and C22 mono- and polyunsaturated fatty acids, and particularly 20∶5ω3.
Abstract: Tetraselmis suecica andDunaliella tertiolecta were grown for 24 hr in the presence of14C sodium bicarbonate and then fed separately to batches of juvenile oysters,Crassostrea gigas, for 3 days.D. tertiolecta contained fatty acids no longer than C18; 22∶6ω3 was absent inT. suecica. Analysis of the oyster fatty acids by radio gas chromatography (GC) showed that oysters were able to incorporate some of the dietary14C label into long-chain fatty acids not supplied in the diet, e.g., C20 and C22 mono- and polyunsaturated fatty acids, and particularly 20∶5ω3. However, the low14C incorporation into fatty acids longer or more unsaturated than those supplied in the diet suggests that elongation and desaturation activity in young oysters is not sufficient to sustain optimum growth.
158 citations
TL;DR: The results indicate that MDA excretion can serve as an indicator of the extent of lipid peroxidation in the diet and, under conditions which preclude a dietary effect, as an index of lipidper oxidation in vivo.
Abstract: Although malondialdehyde (MDA) is extensively metabolized to CO2, small amounts are nevertheless excreted in an acid-hydrolyzable form in rat urine. In this study, urinary MDA was evaluated as an indicator of lipid peroxidation in the diet and in the tissues. MDA was released from its bound form(s) in urine by acid treatment and determined as the TBA-MA derivative by HPLC. MDA excretion by the rat was found to be responsive to oral administration of the Na enol salt and to peroxidation of dietary lipids. Urinary MDA also increased in response to the increased lipid peroxidation in vivo produced by vitamin E deficiency and by administration of iron nitrilotriacetate. Chronic feeding of a diet containing cod liver oil led to increases in MDA excretion which were not completely eliminated by fasting or feeding a peroxide-free diet, indicating that there was increased lipid peroxidation in vivo. MDA excretion was not responsive to Se deficiency or CCl4 administration. DPPD, a biologically active antioxidant, but not BHA, a non-biologically active antioxidant, prevented the increase in MDA excretion in vitamin E deficient animals. The results indicate that MDA excretion can serve as an indicator of the extent of lipid peroxidation in the diet and, under conditions which preclude a dietary effect, as an index of lipid peroxidation in vivo.
145 citations
TL;DR: Results suggest a close relationship of the observed fatty acid changes in individual platelet phospholipids to the altered hematological parameters and platelet-vessel wall interactions produced by cod-liver oil supplementation.
Abstract: The effect of supplementation with cod-liver oil containing eicosapentaenoic acid (EPA), 20∶5ω3, on bleeding times, thrombin-induced platelet aggregation, platelet protein, platelet cholesterol, and the level and fatty acid composition of individual phospholipids in the platelets of human subjects was determined. Measurement of these parameters was conducted before the subjects received the supplement (day 0), after they received the supplement for 14 days (day 14), and 14 days after the supplement was terminated (day 28) so as to monitor recovery. The mean bleeding times exhibited a marked increase (by 81%) with supplementation and returned to near basal (day 0) values within 14 days after the supplement was terminated. Cod-liver oil supplementation significantly reduced thrombin-induced platelet aggregation with a partial recovery being exhibited by day 28. The content of phospholipid, cholesterol and protein (μg/109 platelets) was not significantly different (P>0.05) when isolated from the subjects at day 0, 14 and 28, as neither were the composition of individual phospholipids [phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI) and sphingomyelin (SPH)] given as % of total phospholipid. However, the fatty acid compositions of all platelet phospholipids were altered significantly by the fish oil supplement. In PC, EPA rose from 0.3 to 2.9% of total fatty acids and docosahexaenoate from 0.7 to 1.8% concomitant with a drop in arachidonate (from 14.1 to 9.6%) and linoleate (from 10.2 to 7.9%); these levels approached basal levels 14 days after supplementation was terminated. The highest percentage of EPA with supplementation was found in PE (4.3%), while the arachidonate fell from 38.8 to 30.5%, with low percentages of EPA occurring in PS (0.7%) and PI (0.5%). The level of 24∶1 in SPH increased significantly (from 17.8 to 24.8) with supplementation and reverted to basal values by day 28. These results suggest a close relationship of the observed fatty acid changes in individual platelet phospholipids to the altered hematological parameters and platelet-vessel wall interactions produced by cod-liver oil supplementation.
140 citations
TL;DR: The total lipid content of fruit seeds of the Ribes family ranges by weight from 18.3% in goose-berries (Ribes uva crispa) to 30.5% in black currants (ribes nigrum) as discussed by the authors.
Abstract: The total lipid content of fruit seeds of the Ribes family ranges by weight from 18.3% in goose-berries (Ribes uva crispa) to 30.5% in black currants (Ribes nigrum). Isolation procedures and analytical methods (gas chromatography, mass spectrometry, high performance thin layer chromatography and stereospecific analysis) demonstrate that the oils from Ribes seeds contain up to 19% by weight of gamma-linolenic acid (gamma-LA, C18:3, n-6) in black currant oil. This last Ribes species thus constitutes one of the richest natural sources in gamma-LA yet described. These oils appear promising for critically ill patients who seem unable to convert linoleic acid into subsequent EFA fractions.
113 citations
TL;DR: Triiodothyronine-induced alteration of the lipid pattern in rat-liver mitochondria and microsomes and in mitochondria from the same animals, a meaningful linoleic acid decrease with a similar arachidonic acid increase has been found.
Abstract: Triiodothyronine-induced alteration of the lipid pattern in rat-liver mitochondria and microsomes has been investigated. In mitochondria, a 25% total cholesterol decrease and a 14% phospholipid increase have been detected. In these hyperthyroid rat liver organelles, a strong decrease in the total cholesterol/phospholipid molar ratio occurs. On the contrary, in microsomes from the same animals, a decrease of about 23% has been measured for both total cholesterol and phospholipids; hence, in this fraction, the total cholesterol/phospholipid molar ratio is unaffected by hyperthyroidism. The liver mitochondrial phospholipid composition, unlike the microsomal composition, is altered significantly in hyperthyroid rats; a 7.4% phosphatidylcholine decrease is accompanied by a similar additive percentage increase of both phosphatidylethanolamine and cardiolipin. In regard to total phospholipid fatty acid composition in liver microsomes from hyperthyroid rats, no variation has been observed compared with the control rats, whereas in mitochondria from the same animals, a meaningful linoleic acid decrease with a similar arachidonic acid increase has been found. In addition to fatty acid alteration, the separated mitochondrial phospholipid classes also exhibit some increase in stearic acid. Among phospholipids, cardiolipin changes the most of the esterified fatty acids in hyperthyroid rat liver. In this compound, a strong increase in the percentage of both palmitic and stearic acid and a 32.4% decrease of linoleic acid have been found.
112 citations
TL;DR: It is concluded that thetrans-18∶1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.
Abstract: Four groups of rats were fed diets containing 15% (w/w) high-oleic safflower oil (SFO, rich incis-18∶1 acids), a mixture of 80% partially hydrogenated soybean oil plus 20% corn oil (H+CO, rich intrans-18∶1 acids), lard (L, rich in saturated fatty acids) and corn oil (Co, rich in 18∶2ω6). Fatty acid composition of liver microsomes and activities of the Δ5, Δ6 and Δ9 desaturases were determined. Microsomal Δ6 desaturase activity and arachidonic acid were lower in the H+CO group compared with SFO of L. No difference was found in the Δ5 or Δ6 desaturase activity of CO and SFO groups. Thus, the oleic-acid level of the SFO diet had no effect on the metabolism of 18∶2ω6. Fluorescent polarization studies, usingtrans-parinaric acid as a probe, showed no differences between the physical states of phospholipid vesicles made from lipids isolated from each group. We concluded that thetrans-18∶1 acids in partially hydrogenated soybean oil have a more inhibitory effect than saturated acids on EFA metabolism, even in the presence of adequate amounts of essential fatty acid.
108 citations
TL;DR: In groups given thermally oxidized oils relative liver weight, relative kidney weight, thiobarbituric acid-reactive substances in the liver and reduced glutathione content were increased significantly in proportion to the degree of deterioration of the oil, compared with the group given fresh oil.
Abstract: Thermally oxidized rapeseed oils (4 levels of deterioration; used by a manufacturer of fried fish paste in a conventional manner) were fed to rats at a practical level of concentration. Rats were fed a diet ad libitum for 13 weeks that contained 15% of a test oil. The effects of the diet on several biochemical criteria related to peroxidative alterations were investigated.
102 citations
TL;DR: 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.
Abstract: Indirect 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 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.
97 citations
TL;DR: It looks unlikely that malonaldehyde is the only product of lipid oxidation that produces fluorescent components in lipofuscin complex because fluorescence of the compounds was greatly affected in acidic medium and little influenced in alkaline medium or by the metal chelator.
Abstract: We investigated fluorescence properties of 1,4-dihydropyridine-3,5-dicarbaldehydes and their formation in mild reaction of primary amines and malonaldehyde, in order to clarify the role of malonaldehyde in the formation of fluorescent components of lipofuscin. The compounds exhibited fluorescence with excitation maxima at 375-405 nm and emission maxima at 435-465 nm, which was similar to those of lipofuscin and the fluorescent substances derived from the reaction of oxidized fatty acids with primary amines. Fluorescence of the compounds was greatly affected in acidic medium and little influenced in alkaline medium or by the metal chelator. The compounds lost fluorescence by treatment with sodium borohydride. They were inert to thiobarbituric acid reaction. Some of the fluorescence properties of the compounds were different from those of lipofuscin and the related fluorescent substances. Mild reaction of methylamine with pure malonaldehyde gave a single fluorescent compound, 1,4-dimethyl-1,4-dihydropyridine-3,5-dicarbaldehyde (Ia), and the reaction with the acid hydrolysate of tetramethoxypropane gave Ia and 1-methyl-4-(dimethoxyethyl)-1,4-dihydropyridine-3,5-dicarbaldehyde (IIa), the latter being produced from the impurity in the hydrolysate. These reactions produced a non-fluorescent Schiff base, a 1∶1-adduct of methylamine and malonaldehyde (IIIa), as a major product. It looks unlikely that malonaldehyde is the only product of lipid oxidation that produces fluorescent components in lipofuscin complex.
TL;DR: Treatment of isomeric methyl linoleate hydroperoxides with a Lewis acid, BF3, in anhydrous ether led to a carbon-to-oxygen rearrangement that caused cleavage into shorter-chain aldehydes, which resembled the one catalyzed by the plant enzyme, hydroperoxide lyase.
Abstract: Treatment of isomeric methyl linoleate hydroperoxides with a Lewis acid, BF3, in anhydrous ether led to a carbon-to-oxygen rearrangement that caused cleavage into shorter-chain aldehydes. Methyl (9Z,11E)-13-hydroperoxy-9,11-octadecadienoate afforded mainly hexanal and methyl (E)-12-oxo-10-dodecenoate, whereas methyl (10E,12Z)-9-hydroperoxy-10,12-octadecadienoate cleaved into 2-nonenal and methyl 9-oxononanoate. The 2 aldehydes obtained from each hydroperoxide isomer were uncharacteristic of the complex volatile profile usually obtained by β-scission of oxy radicals derived from homolysis of the hydroperoxide group. Rather, the reaction resembled the one catalyzed by the plant enzyme, hydroperoxide lyase.
TL;DR: Male rats were fed on a fat-free diet for 8 weeks and then switched to diets containing 10% hydrogenated coconut oil (HCO), safflower oil (SFO) or evening primrose oil (EPO), suggesting that conversion of linoleic acid to 18∶3n−6 and possibly to further metabolites may be important for the cholesterol-lowering effect of polyunsaturates.
Abstract: Male rats were fed on a fat-free diet for 8 weeks and then switched to diets containing 10% hydrogenated coconut oil (HCO), safflower oil (SFO) or evening primrose oil (EPO). Half of each group was also given 1% of cholesterol in the diet. After 5 further weeks, plasma, red cell and liver fatty acids were measured in the various lipid fractions. Plasma and liver cholesterol also were estimated. In almost all fractions and on all three diets, feeding cholesterol led to accumulation of the substrates of desaturation reactions and to deficits of the products of these reactions. The results were consistent with inhibition of delta-6, delta-5 and delta-4 desaturation of n-6 essential fatty acids. Since the diets were deficient in n-3 fatty acids, levels were very low but were also consistent with inhibition of desaturation. In contrast, cholesterol had relatively less consistent effects on 20:3n-9, suggesting that desaturation of n-9 fatty acids was less inhibited. Plasma cholesterol levels rose sharply in the HCO and SFO groups but not at all in the EPO group. EPO contains the product of delta-6-desaturation, 18:3n-6, suggesting that conversion of linoleic acid to 18:3n-6 and possibly to further metabolites may be important for the cholesterol-lowering effect of polyunsaturates.
TL;DR: The data suggest that arachidonate release and prostacyclin synthesis are dependent on influx of extracellular calcium and subsequent activation of a Ca2+-dependent phospholipase by a calmodulin-mediated mechanism.
Abstract: Both bradykinin (EC50=8 ng/ml) and the ionophore A23187 (EC50=3×10−7 M) potently stimulated arachidonate release and prostaglandin synthesis in porcine aortic endothelial cells. The response to each was completely dependent on extracellular Ca2+ (EC50=3×10−7 M); no role for intracellular Ca2+ was noted. The rapid Ca2+ influx prompted by either activator was consistent with the time course for arachidonate release. Whereas the arachidonate released in response to bradykinin was trasient, that released in response to A23187 was more prolonged, and paralleled a continued influx of Ca2+. Ca2+ entry elicited by bradykinin was mediated by channels which could not be blocked by verapamil. When Mn2+ was substituted for Ca2+, no stimulation of prostacyclin synthesis was seen in response to A23187; however, the bradykinin response was unaffected. The mechanism of these effects was studied using doses of bradykinin or A23187 which resulted in increases in Ca2+ influx and prostacyclin synthesis of similar magnitude for each agonist. Under these conditions, trifluoperazine blocked elevated prostacyclin synthesis (ID50=5–6×10−6 M for each agonist). Trifluoperazine sulfoxide, however, was much less active. Pimozide inhibited bradykinin-stimulated prostacyclin synthesis at low doses (ID50=3×10−6 M). Trifluoperazine was much less effective against high doses of A23187 (4×10−6 M). These data suggest that arachidonate release and prostacyclin synthesis are dependent on influx of extracellular calcium and subsequent activation of a Ca2+-dependent phospholipase by a calmodulin-mediated mechanism.
TL;DR: The lipid classes, fatty acids of total and individual lipids and sterols of Antarctic krill (Euphausia superba Dana) from two areas of the Antarctic Ocean were analyzed by thin layer chromatography (TLC) and gas liquid chromatography/mass spectrometry (GLC/MS) as discussed by the authors.
Abstract: The lipid classes, fatty acids of total and individual lipids and sterols of Antarctic krill (Euphausia superba Dana) from two areas of the Antarctic Ocean were analyzed by thin layer chromatography (TLC), gas liquid chromatography (GLC) and gas liquid chromatography/mass spectrometry (GLC/MS). Basic differences in the lipid composition of krill from the Scotia Sea (caught in Dec. 1977) and krill from the Gerlache Strait (caught in Mar. 1981) were not observed. The main lipid classes found were: phosphatidylcholine (PC) (33–36%), phosphatidylethanolamine (PE) (5–6%), triacylglycerol (TG) (33–40%), free fatty acids (FFA) (8–16%) and sterols (1.4–1.7%). Wax esters and sterol esters were present only in traces. More than 50 fatty acids could be identified using GLC/MS, the major ones being 14∶0, 16∶0, 16∶1(n−7), 18∶1(n−9), 18∶1(n−7), 20∶5(n−3) and 22∶6(n−3). Phytanic acid was found in a concentration of 3% of total fatty acids. Short, medium-chain and hydroxy fatty acids (C≤10) were not detectable. The sterol fraction consisted of cholesterol, desmosterol and 22-dehydrocholesterol.
TL;DR: The failure to significantly alter membrane lipid saturation/unsaturation in the tissues examined would suggest that a homeostatic mechanism is operative in biological membranes and may act to buffer membranes from the effects of changes in the nature of the dietary lipid intake.
Abstract: Diets in which both the lipid content and composition (polyunsaturated to saturated fatty acid ratio) were varied were fed to rats for 20 weeks, and the effects on the tissue lipid profiles were determined. The fatty acid profile of the plasma lipids, and the phospholipid fatty acids of the mitochondrial and microsomal fractions of liver, heart, kidney and brain, as well as erythrocyte membranes were determined. Despite large differences in the level and type of lipid present in the experimental diets and in the proportion of saturated fatty acids in the plasma lipids in response to the various diets, there was little effect on the proportion of saturated to unsaturated fatty acids in the phospholipids of the various membranes examined. The major effect of altering the dietary level of polyunsaturated to saturated fatty acids was on the ratio of the omega 6/omega 3 series of unsaturated fatty acids in the membrane lipids. This change occurred in all tissues except the brain, in which only a small response to altered dietary lipid intake was observed. The omega 6/omega 3 ratio was elevated upon feeding a diet rich in omega 6 polyunsaturated fatty acids, but decreased when a diet rich in saturated fatty acids was fed. The failure to significantly alter membrane lipid saturation/unsaturation in the tissues examined would suggest that a homeostatic mechanism is operative in biological membranes and may act to buffer membranes from the effects of changes in the nature of the dietary lipid intake.
TL;DR: Skin fatty acids in diabetic rats showed an increase in the proportion of arachidonic acid and a reduction in theportion of linoleic acid and the fatty acid desaturating activity in diabetes may be regulated differently in different tissues.
Abstract: Tissue phospholipid fatty acid compositions in streptozotocin-induced diabetic rats were studied. The major changes in liver, plasma, erythrocyte and heart were increased proportions of linoleic and dihomo-γ-linolenic acids and a decreased proportion of aracchidonic acid. The latter was not significantly changed in phospholipids of kidney, adrenal gland and testis. Skin fatty acids in diabetic rats showed an increase in the proportion of arachidonic acid and a reduction in the proportion of linoleic acid. The fatty acid desaturating activity in diabetes may be regulated differently in different tissues.
TL;DR: In this paper, the genesis of volatile lipid oxidation products, thermal homolytic and acid heterolytic decomposition processes were compared, and no dialdehydes were identified under their thermal decomposition conditions.
Abstract: To elucidate the genesis of volatile lipid oxidation products, thermal homolytic and acid heterolytic decomposition processes were compared. Secondary oxidation products were decomposed thermally (200 C), and the volatiles formed were identified by capillary gas chromatography-mass spectrometry (GC-MS). Oxidation products also were decomposed in the presence of HCl-methanol, and the resulting dimethyl acetals were identified by GC-MS. The volatile thermal decomposition products were those expected by homolytic β-scission on both sides of the hydroperoxide group. No dialdehydes were identified under our thermal decomposition conditions. In contrast, the acetals formed by acid decomposition were those expected by selective heterolytic scission between the hydroperoxide group and the allylic double bond. Dialdehydes identified from acid decomposition of cyclic peroxides and dihydroperoxides included malonaldehyde and 2,4-hexadienedial.
TL;DR: In this article, essential fatty acids were estimated in plasma, red blood cells and liver total phospholipids in rats, mice, hamsters, guinea pigs, rabbits and humans.
Abstract: Essential fatty acids were estimated in plasma, red blood cells and liver total phospholipids in rats, mice, hamsters, guinea pigs, rabbits and humans. There were large species differences, suggesting that different species levels should be borne in mind when choosing an animal for a particular study. The 2 species most susceptible to atheroma, the guinea pig and the rabbit, had very high levels of linoleic acid and low levels of linoleic acid metabolites. n−3 fatty acid levels were low in guinea pigs and rabbits and the ratio of n−3 to n−6 fatty acids also was low in the rat. Mice and hamsters had the highest n−3 levels, suggesting they may be the best species to use for studies on the roles of n−3 essential fatty acids. Mice and hamsters and, in some respect rats, were closest to humans in their fatty acid patterns.
TL;DR: In this paper, synthetic mixtures of C40 to C47 sterol esters in groups of 7 esters were effectively separated and analyzed by capillary gas chromatography-mass spectrometry.
Abstract: Synthetic mixtures of C40 to C47 sterol esters in groups of 7 esters were effectively separated and analyzed by capillary gas chromatography-mass spectrometry. Ammonia chemical ionization of all 20 sterol esters analyzed at a source block temperature of 120 C yielded (M+NH4)+ and (M+H-RCO2H)+ ions of high abundance or as base peak, thereby indirectly indicating the molecular weights of the ester and the sterol and acid moieties. Ammonia CI spectra of all esters containing a Δ5-sterol moiety exhibited in addition to the above 2 ions an M+NH4-RCO2 H fragment. At a source block temperature of 150 C, M+H-RCO2 H fragment was the base peak for all esters, and there was little or no indication of an (M+NH4)+ adduct ion. Protonated molecules were not observed for any esters analyzed by methane or isobutane CI. Molecular ions of 3–14% intensity were obtained for only 3 of the esters analyzed by electron impact; they contained a Δ7-bond in the sterol nucleus, and the acid moiety was either saturated normal or branched chain or contained a single double bond. The base peak was a function of both the acid and sterol moieties of the sterol ester. The esters containing both saturated straight chain acid and saturated sterol moieties exhibited a base peak at m/z 215. The Δ5-sterol esters with saturated branched or straight chain acid moieties exhibited base peaks at M-RCO2 H. Other ions also were of diagnostic value.
TL;DR: The unique ether-linked phospholipid was identified only in an amniotic fluid obtained from women during labor, and its alkyl side chain was composed exclusively of octadecyl residue.
Abstract: Evidence is presented for the existence of platelet-activating factor (PAF) in human amniotic fluid during labor by gas-liquid chromatographic (GLC) and mass-spectrometric (MS) analysis. The unique ether-linked phospholipid was identified only in an amniotic fluid obtained from women during labor, and its alkyl side chain was composed exclusively of octadecyl residue.
TL;DR: The fatty acid composition of oyster larvae at various stages, as well as of the algal diet, were determined by gas liquid chromatography (GC) as discussed by the authors, which showed that 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.
Abstract: The 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.
TL;DR: The data show that MDA is not generated in the cells by a lipoxygenase pathway and that 15-HPETE and cooxidation are not involved in MDA formation, and support the hypothesis that cell proliferation is controlled in part by general peroxidation reactions rather than the specificPeroxidation reaction involved in prostanoid synthesis.
Abstract: Primary cultures of smooth muscle cells were established from the medial layer of guinea pig aorta. Confluent cells at passage level 4-6 were challenged with arachidonic acid and treated with a number of antioxidants and inhibitors of specific lipid peroxidation pathways. Lipid peroxidation was measured by the thiobarbituric acid test for malondialdehyde (MDA) and the isolation of hydroperoxy fatty acids (HPETE) by high performance liquid chromatography (HPLC). Prostanoids were measured by radioimmunoassay and the separation of labeled compounds by HPLC. MDA, 6-keto-PGF1 alpha, and PGE2 were formed when cells were challenged with arachidonic acid and these cells synthesized small amounts of one HPETE isomer, 15-HPETE. The HPETE isomers characteristic of the lipoxygenase pathway, 12-HPETE and 5-HPETE, were not detected. Furthermore, the lipoxygenase inhibitors, eicosatetraynoic acid (ETYA) and 6,7-dihydroxycoumarin (Esculetin), did not block MDA formation. These data show that MDA is not generated in the cells by a lipoxygenase pathway. The cyclooxygenase inhibitors, indomethacin and ETYA, did not block MDA formation but these agents blocked the formation of 15-HPETE. These data show both that 15-HPETE is generated by a cooxidation pathway and that 15-HPETE and cooxidation are not involved in MDA formation. Three inhibitors of cytochrome P450 linked lipid peroxidation, 2-amino-3-ethoxycarbonyl-6-benzyl-4, 5,6,7-tetrahydrothieno-[2,3-C]-pyridine (Tinoridine), 3-methyl-1,2-di-3-pyridyl-1-propanone (Metyrapone) and phenobarbital, did not block MDA formation. These data support earlier studies that indicated that MDA is not generated by a P450 pathway. Cells contained a bound precursor that decomposed to MDA when cells were treated with Fe3+. The cells exhibited autofluorescence and concentric lamellae in lipid droplets that are characteristic of ceroid-lipofuscin. These observations are consistent with lipid peroxidation through increased peroxisomal activity leading to the generation of MDA and the accumulation of ceroid-lipofuscin. The natural antioxidants, vitamin E and vitamin E quinone (EQ), and the synthetic antioxidants, butylated hydroxytoluene and nordihydroguaiaretic acid (NDGA), alpha-naphthol (alpha-N) and propyl gallate (PrGa), all blocked MDA formation in confluent smooth muscle cells, showing that these antioxidants did not function solely as specific inhibitors of lipoxygenase, cooxidation or P450 pathways. Cell proliferation was measured in cells challenged with arachidonic acid and treated with antioxidants and other inhibitors. The least cytotoxic and most potent antioxidant, EQ, blocked MDA formation in confluent cells and promoted grow
TL;DR: A 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.
Abstract: A 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.
TL;DR: The data demonstrated that chloroplasts were a subcellular site for triacylglycerol biosynthesis in spinach leaves, and associated primarily with gradient fractions containing oil bodies and intact chloroplASTs.
Abstract: The 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.
TL;DR: 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.
Abstract: The 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.
TL;DR: Two epimers of methyl (12S,13S)-(E)-12,13-epoxy-9-hydroperoxy-10-octadecenoate were isolated after esterification of a mixture of fatty acids obtained from decomposition of (13S,9Z,11E)-13-hexanal hexanal, 9, 11,11-decdecadecadienoic acid by an Fe++-cysteine catalyst as mentioned in this paper.
Abstract: Two epimers of methyl (12S,13S)-(E)-12,13-epoxy-9-hydroperoxy-10-octadecenoate were isolated after esterification of a mixture of fatty acids obtained from decomposition of (13S)-(9Z,11E)-13-hydroperoxy-9,11-octadecadienoic acid by an Fe++-cysteine catalyst. These epimeric epoxyhydro-peroxyoctadecenoates were decomposed by heat (210 C) in the injection port of a gas chromatograph, and the cleavage fragments were subsequently separated by gas chromatography (GC) and identified by mass spectrometry (MS). Among the scission products obtained, the most prominent in the GC peak profile were methyl octanoate and methyl 9-oxononanoate. Other peaks were identified as pentane, 1-pentanol, hexanal, 2-heptanone, 2-pentylfuran, methyl heptanoate, 2-octenal, 4,5-epoxy-2-decenal, methyl 8-(2-furyl)-octanoate, 11-oxo-9-undecenoate and methyl 13-oxo-9,11-tridecadienoate. In addition, 3,4-epoxynonanal, methyl 8-oxooctanoate, 3-hydroxy-2-pentyl-2,3-dihydrofuran and methyl 10-oxodecanoate were tentatively identified. Except for the furan compounds, the formation of the fragmentation products could be explained by conventional free-radical scission mechanisms.
TL;DR: The results revealed that iso-octane and cyclohexane are superior to the other solvents examined for enzymatic fat splitting in organic solvent systems.
Abstract: The effect of organic solvents on the stability and catalytic activity of the microbial lipase fromCandida rugosa for hydrolysis of triglyceride (fat splitting) has been examined. The solvents examined were 5 hydrocarbons (n-hexane, n-heptane, n-octane, iso-octane and cyclohexane) and 3 ethers (diethyl-ether, diisopropylether and di-n-butylether). The results revealed that iso-octane and cyclohexane are superior to the other solvents examined for enzymatic fat splitting in organic solvent systems.
TL;DR: In this article, a human erythrocyte membrane was irradiated with near ultraviolet (UV) light in the presence of a photosensitizer, hematoporphyrin, but no production of 2-thiobarbituric acid-reactive materials (malonaldehyde and its precursors) was detected.
Abstract: Lipid hydroperoxide was generated in human erythrocyte membranes by irradiation with near ultraviolet (UV) light in the presence of a photosensitizer, hematoporphyrin, but no production of 2-thiobarbituric acid-reactive materials (malonaldehyde and its precursors) was detected. Incubation of the irradiated membranes with CuSO4 led to increased levels of hydroperoxide and formation of malonaldehyde. Hydroperoxides were essential for initiating the Cu(II)-catalyzed peroxidation as no significant activity was observed with nonirradiated membranes and Cu(II) unless an organic peroxide, either t-butyl hydroperoxide or cumene hydroperoxide, was added. Catalytic activity was also found with Fe(II), but not with other metal ions tested. The peroxidation catalyzed with Cu(II) was partially inhibited by several singlet oxygen quenchers but was not affected by superoxide dismutase, catalase or OH radical scavengers. The possible involvement of singlet oxygen in the Cu(II)-catalyzed peroxidation reaction was further supported by a 3-fold enhancement of malonaldehyde production in D2O.
TL;DR: The findings show that, although stored (n−3) PUFA were not exhausted after a 6-month dietary deficiency, the incorporation of essential fatty acids (EFA) into vitellogenin during the early stages of oogenesis was low, suggesting changes in egg composition that may influence hatching.
Abstract: During the 6 months of vitellogenesis, 3-year-old female trout (Salmo gairdneri) were fed either an enriched (E) or an (n−3) polyunsaturated fatty acid (PUFA)-deficient (D) diet; serum vitellogenin (VG) and lipoproteins (d<1.21 g/ml) were analyzed at the third month of vitellogenesis (September) and at ovulation (December). The serum content of high density lipoproteins (HDL), the major protein class, maintained a mean value of 1500 mg/dl at both stages and with both diets. On the contrary, very low density lipoproteins (VLDL) were 90% higher during vitellogenesis than at spawning time, whereas excess vitellogenin circulated at this period (6580 mg/dl serum with diet E). The diet deficient in (n−3) lowered serum vitellogenin content by 16% in September and by 26% in December. The degree of (n−3) PUFA incorporation moderately decreased in low density lipoproteins (LDL) and in HDL with the (n−3)-deficient diet. The effect was more pronounced for 20∶5. On the other hand, essential 22∶6 was incorporated into vitellogenin at the same rate in September as in December with diet E (23% and 25%, respectively), whereas after a 3-month deficiency, the percentage fell to 12%; this percentage rose again to 19% at spawning time. These findings show that, although stored (n−3) PUFA were not exhausted after a 6-month dietary deficiency, the incorporation of essential fatty acids (EFA) into vitellogenin during the early stages of oogenesis was low, suggesting changes in egg composition that may influence hatching.