Showing papers in "Lipids in 1982"
TL;DR: In vitro experiments using [1,3-14C] MA showed that MA is metabolized primarily in the mitochondria via reactions involving O2 utilization and14CO2 production, and 14C-Acetate appeared to be the major accumulating metabolite in rat liver mitochondrial preparations following a 120-min incubation with14C-MA.
Abstract: The metabolism of malonaldehyde (MA) was investigated in vivo using male Wistar rats and in vitro using rat liver mitochondria. Twelve hr after intubation with [1,3-14C] MA, 60–70%, 5–15% and 9–17% of administered radioactivity was recovered in expired CO2, feces and urine, respectively. In rats intubated with [1,2-14C] acetate, the corresponding values were 68–82%, 1–2% and 2–3%.14CO2 evolution was initially slower after14C-MA administration than after14C-acetate administration and more radioactivity was excreted in the feces and urine. In vitro experiments using [1,3-14C] MA showed that MA is metabolized primarily in the mitochondria via reactions involving O2 utilization and14CO2 production. The apparent Km and Vmax were 0.5 mM and 9.3 nmol/min/mg protein for O2 uptake, respectively, and 2.0 mM and 2.4 nmol/min/mg protein for14CO2 production. Addition of malonic acid to mitochondrial incubates at concentrations inhibitory to succinate dehydrogenase did not affect MA-induced O2 uptake but enhanced14CO2 production from14C-MA.14C-Acetate appeared to be the major accumulating metabolite in rat liver mitochondrial preparations following a 120-min incubation with14C-MA. A probable biochemical route for MA metabolism involves oxidation of MA by mitochondrial aldehyde dehydrogenase followed by decarboxylation to produce CO2 and acetate.
189 citations
TL;DR: Competitive inhibition studies with various scavengers of hydroxyl radicals or singlet oxygen and the absence of significant reaction enhancement by D2O indicated that neither of these reactive oxygen species was a major mediator in the Cu++-H2O2 oxidative system.
Abstract: Cu++ was uniquely capable of catalyzing the peroxidation of rat erythrocyte membrane lipid in the presence of 10 mM H2O2, whereas several other transition metal ions were without significant effect. In contrast, peroxidation of soybean phospholipid liposomes could be catalyzed with decreasing efficiency by Co++, Cu++, Pb++, or Cr+++ also in the presence of H2O2. The effect of imidazole on Cu++-catalyzed lipid peroxidation was stimulatory in liposomes and inhibitory in membrane preparations, whereas EDTA, histidine, citrate and alanine inhibited peroxidation in both systems. EDTA could stop the peroxidation after initiation, but catalase could not, indicating that Cu++ alone was necessary for the propagation of the chain reaction. Competitive inhibition studies with various scavengers of hydroxyl radicals or singlet oxygen and the absence of significant reaction enhancement by D2O indicated that neither of these reactive oxygen species was a major mediator in the Cu++-H2O2 oxidative system. A copper-oxygen complex may be directly involved in the initiation of peroxidation. Normal erythrocyte membranes and phospholipid liposomes also differ in their sensitivities toward external oxidative stress. In the absence of H2O2, Cu++ (0.2 mM) was capable of catalyzing lipid peroxidation in liposomes, aged erythrocyte membranes and membranes from vitamin-E-deficient rats; however, freshly prepared membranes from control rats and liposomes containing α-tocopherol required H2O2 greater than 2 mM for the catalytic effect of Cu++ to be observed.
140 citations
TL;DR: Studies of photosensitized oxidation of methyl linoleate show that the greater relative concentration of 9- and 13-hydroperoxides than 10- and 12-hydraulic peroxides is characteristic of singlet oxygenation and not due to either simultaneous autoxidation or type 1 photosenitized oxidation.
Abstract: Studies of photosensitized oxidation of methyl linoleate show that the greater relative concentration of 9- and 13-hydroperoxides than 10- and 12-hydroperoxides is characteristic of singlet oxygenation and not due to either simultaneous autoxidation or type 1 photosensitized oxidation. Cyclization of the internal 10- and 12-hydroperoxides accounts for their lower relative concentrations. Secondary products separated by silicic acid and high pressure liquid chromatography were characterized spectrally (IR, UV,1H-NMR,13C-NMR, GC-MS). Major secondary products included diastereomeric pairs of 13-hydroperoxy-10,12-epidioxy-trans-8-octadecenote (I and III) and 9-hydroperoxy-10,12-epidioxy-trans-13-octadecenoate (II and IV); minor secondary products included hydroperoxy oxy genated and epoxy esters. Thermal decomposition of the hydroperoxy cyclic peroxides produced hexanal and methyl 10-oxo-8-decenoate as major volatiles from I and III and methyl 9-oxo-nonanoate and 2-heptenal from II and IV. Hydroperoxy cyclic peroxides may be important sources of volatile decomposition products of photooxidized fats.
121 citations
TL;DR: Open-tubular gas chromatographic analysis of fatty acids in the lipids from the seeds of 20 species of Gymnospermae showed that they all contained nonmethylene-interrupted polyenoic (NMIP) acids as minor components and palmitic, oleic, linoleic and α-linolenic acids as major components.
Abstract: Open-tubular gas chromatographic analysis of fatty acids in the lipids from the seeds of 20 species of Gymnospermae showed that they all contained nonmethylene-interrupted polyenoic (NMIP) acids as minor components and palmitic, oleic, linoleic and α-linolenic acids as major components. The NMIP acids have an additional 5,6-ethylenic bond in ordinary plant unsaturated fatty acids and the following C2 elongation acids:cis-5,cis-9-octadecadienoic acid (5,9–18∶2) (I); 5,9,12–18∶3 (II); 5,9,12,15–18∶4, 5,11–20∶2, 5,11,14–20∶3 (III); and 5,11,14,17–20∶4 (IV). The main NMIP acids found in neutral lipids are I in two species ofTaxus, II in seven species of Pinaceae, III in two species of Podocarpaceae,Torreya nucifera, Cycas revoluta, andGinkgo biloba, and III and IV in each of three species of Taxodiaceae, and Cupressaceae. The polar lipids constitute the minor fraction of seed lipids in general. The content and composition of NMIP acids in these lipids differe considerably from those in neutral lipids. Analysis of the partial cleavage products of triacylglycerols showed that the NMIP acids distribute mainly in the 1,3-position.
115 citations
TL;DR: The antioxidant activities of 4 tocopherols, tocol, and a water-soluble model analog of α-tocopherol were compared and oxidation was catalyzed by Fe2+-ascorbate to determine the mechanism of possible antioxidant effect of the compounds used.
Abstract: The antioxidant activities of 4 tocopherols, tocol, and a water-soluble model analog of α-tocopherol were compared. Egg lecithin liposomes were used and oxidation was catalyzed by Fe2+-ascorbate. The activities decreased in the order α->β->γ->δ-tocopherol>tocol, in agreement with their potencies in vivo. The water-soluble analog was the least effective. Activity depended on the molar ratio of antioxidant to unsaturated lipid, with one molecule each of the α-, β-, γ-, δ-tocopherol and tocol capable of protecting, respectively, 220, 120, 100, 30 and 20 molecules of polyunsaturated fatty acid. The mechanism of possible antioxidant effect of the compounds used is discussed.
113 citations
TL;DR: It is shown that there is ample precursor present for the synthesis of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet activatin factor) by a deacylation-reacylation pathway.
Abstract: This study was undertaken to determine if rabbit neutrophils contain sufficient ether-linked precursor for the synthesis of 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet activatin factor) by a deacylation-reacylation pathway. The phospholipids from rabbit peritoneal polymorphonuclear neutrophils were purified and quantitated, and the choline-containing and ethanolamine-containing phosphoglycerides were analyzed for ether lipid content. Choline-containing phosphoglycerides (37%), ethanolamine-containing phosphoglycerides (30%), and sphingomyelin (28%) were the predominant phospholipid classes, with smaller amounts of phosphatidylserine (5%) and phosphatidylinositol (<1%). The choline-linked fraction contained high amounts of 1-O-alkyl-2-acyl-(46%) and 1,2-diacyl-sn-glycero-3-phosphocholine (54%), with a trace of the 1-O-alk-1′-enyl-2-acyl species. The ethanolamine-linked fraction contained high amounts of 1-O-alk-1′-enyl-2-acyl-(63%) and 1,2-diacyl-sn-glycero-3-phosphoethanolamine (34%), and a low quantity of the 1-O-alkyl-2-acyl species (3%). The predominant 1-O-alkyl ether chains found in thesn-1 position of the choline-linked fraction were 16∶0 (35%), 18∶0 (14%), 18∶1 (26%), 20∶0 (16%), and 22∶0 (9%). The major 1-O-alk-1′-enyl ether chains found in thesn-1 position of the ethanolamine-linked fraction were 14∶0 (13%), 16∶0 (44%), 18∶0 (27%), 18∶1 (12%) and 18∶2 (3%). The major acyl groups in thesn-1 position of 1,2-diacyl-sn-glycero-3-phosphocholine and 1,2-diacyl-sn-glycero-3-phosphoethanolamine were 16∶0, 18∶0 and 18∶1. The most abundant acyl group in thesn-2 position of all classes of choline- and ethanolamine-linked phosphoglycerides was 18⩺2. Although this work does not define the biosynthetic pathway for platelet activating factor, it does show that there is ample precursor present to support its synthesis by a deacylation-reacylation pathway.
110 citations
TL;DR: Fatty acid analysis of liver and spleen ethanolamine glycerophosphatide revealed that, as the level of 18∶3ω3 in the diet increased, the elongated, desaturated metabolites of the ω6 series decreased and the �ω3 series increased, leading to depression in the amount of the precursor of the 2-series prostaglandins (PG).
Abstract: Semipurified diets containing ratios of alpha-linolenic acid (18:3 omega 3) to linoleic acid (18:2 omega 6) of 1/32, 1/7, 1/1, and 35/1 in the form of corn oil, soybean oil, soybean/linseed oil mix and linseed oil were fed to rats for 2 months The first 3 diets were fed to another group of rats for 4 months and to a group through the second generation Fatty acid analysis of liver and spleen ethanolamine glycerophosphatide revealed that, as the level of 18:3 omega 3 in the diet increased, the elongated, desaturated metabolites of the omega 6 series decreased and the omega 3 series increased Noteworthy was the depression in the amount of the precursor of the 2-series prostaglandins (PG) as the omega 3 levels increased Synthesis of PG by liver of rats fed 2 or 4 months markedly decreased, but at 2 months in thymus and spleen, it showed a trend toward decreasing only Brain slices showed no decrease in PGF2 alpha synthesis after 4 months, but did decrease significantly after feeding the diets to the second generation Synthesis of PGE2 by spleen homogenate from the second generation also significantly decreased The replacement of omega 6 series fatty acids by omega 3 series is explained by the effective competition of 18:3 omega 3 over 18:2 omega 6 for the delta 6 desaturase Depressions in PG synthesis by high dietary 18:3 omega 3 is explained by the competitive inhibition of the PG synthetase complex by 20:5 omega 3 as well as by the decreased levels of 20:4 omega 6
100 citations
TL;DR: In this paper, complex mixtures of wax esters, steryl esters and triacylglycerols were analyzed using combined high resolution gas chromatography and electron impact and chemical ionization quadrupole mass spectrometry.
Abstract: Complex mixtures of wax esters, steryl esters and triacylglycerols isolated from representative biological and geochemical samples have been analyzed using combined high resolution gas chromatography and electron impact and chemical ionization quadrupole mass spectrometry. These low volatility neutral lipids containing up to 65 carbons were chromatographed intact on 15–20 m high-temperature (upper limit: 370 C) persilylated SE-52 and SE-30 glass capillary columns. Discrimination effects due to adsorptive losses and degradation were minimized using a nonvaporizing on-column injector and a direct all-glass capillary connection (370 C) to the quadrupole mass spectrometer. Structural information regarding the fatty acid and alcohol moieties was found to be maximal for methane-CI spectra in the case of wax and steryl esters, whereas EI spectra were most useful in interpreting triacylglycerol structures. Principal features of the EI and CI fragmentation patterns are discussed. The molecular composition of complex mixtures of these lipids is reconstructed for selected samples.
93 citations
TL;DR: The use of a cholesteryl ether marker is demonstrated in the assay of phospholipid transfer protein activity and in assessing phospholIPid vesicle-cell interactions.
Abstract: Radiolabeled hexadecyl cholesteryl ether can serve as an effective marker for liposomes in a variety of studies. This paper demonstrates the use of a cholesteryl ether marker in the assay of phospholipid transfer protein activity and in assessing phospholipid vesicle-cell interactions. The cholesteryl ether has the advantages of ease of synthesis, metabolic inertness, lipid solubility and nonexchangeability.
85 citations
TL;DR: It is suggested that they may be produced de novo by a route involving nor-isoprenoid pyrophosphates and nor-squalene as intermediates, rather than as bacterial degradation products of brassicasterol (or related sterols) as previously suggested in the literature.
Abstract: The major 4α-monomethyl sterol of the dinoflagellateGymnodinium simplex was identified as (24S)-4α,24- dimethylcholestan-3β-ol. The major 4-demethyl sterols were characterized as (24R)-24-methylcholesta-5,22-dien-3β-ol (brassicasterol) and 27-nor-(24R)-24-methylcholesta-5,22-dien-3β-ol. The latter sterol has the opposite configuration at C-24 to that assigned to occelasterol, which has the same basic structure and has previously been reported as a constituent of the sterols of a marine worm. 24-Nor-cholesta-5,22-dien-3β-ol was also identified along with several other trace sterols. The co-occurrence of 27-nor-(24R)-cholesta-5,22-dien-3β-ol together with 24-nor-cholesta-5,22-dien-3β-ol and brassicasterol provides new evidence for the biosynthetic origins of the two former nor-sterols. It is suggested that they may be produced de novo by a route involving nor-isoprenoid pyrophosphates and nor-squalene as intermediates, rather than as bacterial degradation products of brassicasterol (or related sterols) as previously suggested in the literature.
83 citations
TL;DR: Eicosatrienoic acids were the most effective inhibitors of cell proliferation in each fatty acid family and 20∶3(n-9) was the most potent eicosalic acid.
Abstract: Primary cultures of smooth muscle cells were established from the medial layer of guinea pig aorta. Cells at passage level 4 were treated with different series of fatty acids belonging to the n-9, n-6 and n-3 families. Lipid peroxidation was measured by the thiobarbituric acid assay and prostaglandin biosynthesis was measured by the radioimmunoassay of PGE and 6-keto-PGF1α. Cell proliferation was estimated from the total cell number of cultures seeded at low density. 18∶1(n-9) did not form lipid peroxides and this fatty acid stimulated cell proliferation. All fatty acids which generated lipid peroxides inhibited cell proliferation, but inhibition was correlated with the degree of lipid peroxidation only in the n-9 fatty acid family. 22∶4(n-6) and 22∶6(n-3) inhibited prostaglandin biosynthesis. 18∶2(n-6), 18∶2(n-9), 18∶3(n-3), 20∶2(n-9), 20∶3(n-3) and 20∶5(n-3) had no effect on prostaglandin biosynthesis. 18∶3(n-6), 20∶3(n-6) and 20∶4(n-6) generated prostaglandins. 20∶3(n-9) generated metabolites with prostaglandin immunoreactivity. The inhibition of cell proliferation did not correlate with enhanced or inhibited prostaglandin synthesis. The inhibition of cell proliferation was related to the structures of the different polyunsaturated fatty acid families decreasing in the order n-9>n-6>n-3. Eicosatrienoic acids were the most effective inhibitors of cell proliferation in each fatty acid family and 20∶3(n-9) was the most potent eicosatrienoic acid. These data show that specific as yet unrecognized products of fatty acid metabolism are responsible for the inhibition of cell proliferation.
TL;DR: Fatty acid profiles of polar lipids and triacylglycerols were determined for 6 tissues of the hardshell clam (Mercenaria mercenaria), namely, mantle, gill, mouth, foot, digestive tract/gonadal tissue and adductor muscle.
Abstract: Fatty acid profiles of polar lipids and triacylglycerols were determined for 6 tissues of the hardshell clam (Mercenaria mercenaria), namely, mantle, gill, mouth, foot, digestive tract/gonadal tissue and adductor muscle. The largest concentrations of nonmethylene-interrupted dienoic (NMID) fatty acids were found in the gill, mantle, and foot. Structural analyses were undertaken to determine the double bond configurations of the various NMID isomers. The major 22C NMID species were Δ7,13- and Δ7,15-docosadienoic acid. The major 20C NMID species were Δ7,11- and Δ7,13-eicosadienoic acid and Δ5,11-eicosadienoic acid.
TL;DR: The fatty acyl components of the phospholipids from the spongePetrosia ficiformis consisted predominantly of branched, especially iso and anteiso acids, which are the hitherto unknown Z,Z-25-methyl-5,9-hexacosadienoic and Z, Z-24- methyl-5-9- hexacosatrienoic acids.
Abstract: The fatty acyl components of the phospholipids from the spongePetrosia ficiformis consisted predominantly of branched, especially iso and anteiso acids. The two major components of the complex mixture are the hitherto unknown Z,Z-25-methyl-5,9-hexacosadienoic and Z,Z-24-methyl-5,9-hexacosadienoic acids. Other unknown acids are: 7,13,16-docosatrienoic acid, 15-methyldocosanoic acid, 15-methyltricosanoic acid and 24-methyl-5,9-pentacosadienoic acid. Short branched-chain fatty acids, presumably of bacterial origin, are considered to be the possible bioprecursors of these novel phospholipid constituents. The major phospholipids were PE, PC, PG, PS and PI. The distribution of fatty acids among the phospholipid classes was also studied.
TL;DR: The data suggest that zinc deficiency may be one of the important factors in the causation of polyunsaturated fatty acid deficiency, which in turn, may induce serum hypertriglyceridemia.
Abstract: The effects of zinc deficiency and testosterone on fatty acid composition of plasma lipids and microsomes of liver, intestine and testes were studied. The activities of fatty acid desaturase (delta 6 and delta 5) in rat liver and testes were also measured. A significant decrease in the level of arachidonic acid was observed in plasma of normal rats fed the zinc-deficient diet. Castration significantly decreased arachidonic acid but increased 20:3 fatty acid, which is negligible in normal rats. Testosterone and zinc administration restored arachidonic acid to normal values. Zinc deficiency does not significantly change the fatty acid profile in liver, but castration decreased both arachidonic and 22:6 fatty acid. Intestinal mucosal microsomes showed that the predominant fatty acid in this tissue, palmitic acid, is independent of zinc status, whereas polyunsaturated fatty acids 18:2 and 20:4 were decreased by zinc-deficient diet or castration. Zinc deficiency sharply decreased 22:5 fatty acid and to some extent, other polyunsaturated fatty acids in testis microsomes. These changes in fatty acids are in agreement with increased delta 9 desaturation and decreased delta 5 desaturase activity. In testes, both delta 6 and delta 5 desaturase activities are decreased in zinc deficiency. It appears that zinc influences the conversion of linoleic to arachidonic acid, whereas testosterone influences delta 6 desaturase activity. The data suggest that zinc deficiency may be one of the important factors in the causation of polyunsaturated fatty acid deficiency, which, in turn, may induce serum hypertriglyceridemia.
TL;DR: Agreement was excellent between observed and predicted composition for echidna, koala, Tammar wallaby, guinea pig and pig milk, and agreement was reasonable for dog, cat, horse and cow milk.
Abstract: Milk triglycerides from the echidna, koala, Tammar wallaby, guinea pig, dog, cat, Weddell seal, horse, pig and cow were subjected to fatty acid and stereospecific analysis to determine the positional distribution of the fatty acids in the triglycerides. The samples presented a wide range of fatty acids, most of which varied in content among species. The compositions of the acids at the 3 positions also varied among species, reflecting the content of these acids in the triglycerides. However, there was a general similarity in fatty acid positional distribution patterns for all the species with the exception of the echidna. The echidna exhibited a completely different fatty acid positional distribution pattern. The saturated acids were preferentialy esterified at the sn-1-position whereas the unsaturated acids were selectively esterified at the sn-2-position. The triglyceride carbon number distribution of milk from the above species (with the exception of the Weddell seal) was determined by gas liquid chromatography and compared to that predicted by the 1-random-2-random-3-random fatty acid distribution hypothesis. Agreement was excellent between observed and predicted composition for echidna, koala, Tammar wallaby, guinea pig and pig milk, and agreement was reasonable for dog, cat, horse and cow milk. Results are discussed in relation to biochemical mechanisms.
TL;DR: In this paper, photosensitized-oxidized linolenate was separated by polar phase HPLC and characterized by thin layer and gas liquid chromatography and by ultraviolet, infrared, nuclear magnetic resonance and mass spectrometry.
Abstract: Previous studies of secondary oxidation products by high-pressure liquid chromatography (HPLC) of autoxidized methyl oleate, linoleate and linolenate and photosensitized-oxidized linoleate are extended to photosensitized-oxidized linolenate. Photosensitized-oxidized linolenate was fractionated by silicic acid chromatography with diethyl ether/hexane mixtures. Selected silicic acid chromatographic fractions were separated by polar phase HPLC and characterized by thin layer and gas liquid chromatography and by ultraviolet, infrared, nuclear magnetic resonance and mass spectrometry. Secondary products from the photosensitized oxidation mixtures (containing 8.2 to 29.0% monohydroperoxides) included keto- and epoxy-dienes (0.4–1.6%), hydroperoxy epidioxides (0.8–4.9%), hydroperoxy bicyclic monoenes (0.1–0.3%), dihydroperoxides (1.0–5.6%), and hydroperoxy bisepidioxides (0.7–1.6%). Some of these secondary products are new and unique to photosensitized oxidation. Cyclization of the 10-, 12-, 13- and 15-hydroperoxides of linolenate would account for their lower relative concentration than that found for the 9- and 16-hydroperoxides. Dihydroperoxides may be derived from monohydroperoxides by singlet oxygenation or free radical oxidation. The hydroperoxy bis-epidioxides may be formed by further serial cyclization of the hydroperoxy epidioxides from 10- and 15-monohydroperoxides. Dihydroperoxides, hydroperoxy epidioxides and hydroperoxy bis-epidioxides are suggested as important flavor precursors in oxidized fats.
TL;DR: Inclusion of garlic powder in the atherogenic diet enhanced the percentage of HDL whereas no change was observed in HDL cholesterol levels, and on a cholesterol-containing diet, high density lipoproteins (HDL) and HDL-cholesterol levels were decreased.
Abstract: The hypocholesteremic activity of garlic was tested by incorporation freeze-dried garlic powder at 0.5, 1.0, 2.0 and 3.0% levels in an atherogenic diet fed to rats. It was observed that 0.5 and 1.0% levels were not effective whereas the other 2 levels were. The group fed 2.0% garlic powder had much lower serum cholesterol level than the one fed 3%. The increased levels of low density lipoproteins (LDL) and LDL-cholesterol in rats fed the atherogenic diet were partly reversed in rats receiving a supplement of 2% garlic powder. On a cholesterol-containing diet, high density lipoprotein (HDL) and HDL-cholesterol levels were decreased. Inclusion of garlic powder in the atherogenic diet enhanced the percentage of HDL whereas no change was observed in HDL cholesterol levels. Commercial garlic pearls (equivalent to 0.15% garlic powder in the diet) produced a significant decrease in serum and liver cholesterol levels in rats fed the atherogenic diet. On the other hand, asafoetida at 1.5% level failed to reduce the serum cholesterol levels in the cholesterol-fed rats.
TL;DR: The biosynthesis of essential (n−6) fatty acids was depressed by the TRANS supplement in EFA- deficient as well as in non-EFA-deficient animals.
Abstract: Studies are reported on the effects of dietarytrans fatty acids on the 6- and 9-acyl desaturase activities in the liver microsomes of rats fed essential fatty acid (EFA)-deficient and non-FFA-deficient diets. In experiment I, weanling male rats were fed a semisynthetic diet with either 10% safflower oil (SAF) or 10% hydrogenated coconut oil (HCO). At the age of one year, half of the dietary fat was replaced by a supplement containing elaidate, linolelaidate andcis,trans-trans,cis-18∶2 (TRANS) for 12 weeks. In experiment II, male rats which were kept from weaning on a 10% SAF diet for one year received one of the following fat supplements for a 12-week period: 10% HCO, 9% HCO+1% TRANS, or 5% HCO+5% TRANS. Feeding TRANS depressed the 6-desaturase activity in the liver microsomes, especially in the EFA-deficient rats (HCO+TRANS group of experiment I). Unlike the 6-deaturase activity, the 9-desaturase activity was not inhibited by the dietarytrans fatty acids and was significantly stimulated in the non-EFA-deficient rats (SAF+TRANS group of experiment I and HCO+TRANS groups of experiment II). This was evidenced by incubation reactions and by comparisons of fatty acid consumptions and microsomal fatty acid levels, showing extra biosynthesis of 16∶1 and 18∶1 when TRANS was fed. The biosynthesis of essential (n−6) fatty acids was depressed by the TRANS supplement in EFA-deficient as well as in non-EFA-deficient animals.
TL;DR: In this paper, the structure of cerebrosides and ceramides was investigated from immature and mature soybeans, and structures of the constituents were investigated, and possible metabolic relations of plant sphingolipids based on composition were discussed.
Abstract: Ceramides and cerebrosides were isolated from immature and mature soybeans, and structures of the constituents were investigated. As component fatty acids, normal, 2-hydroxy and 2,3-dihydroxy acids were found in ceramides, whereas only normal and 2-hydroxy acids were identified in cerebrosides. The principal fatty acid component was 2-hydroxylignoceric acid in ceramides, and 2-hydroxypalmitic acid in cerebrosides. Sphingoids in ceramides consisted mainly of trihydroxy bases, with 4-hydroxy-trans-8-sphingenine being predominant. In contrast, cerebrosides contained mainly dihydroxy bases, the principal constituent beingtrans-4,trans-8-sphingadienine. The only sugar in cerebrosides was glucose. The constituents of the two sphingolipids were similar to each other in immature and mature seeds. Possible metabolic relations of plant sphingolipids, based on composition, are discussed.
TL;DR: It appeared that the substances formed from the reaction of LOOH with BSA were crosslinked polymers as evidenced by column chromatography and polyacrylamide gel electrophoresis and their fluorescent intensities correlated well with the thiobarbituric acid (TBA) test.
Abstract: The fluorescent substances produced by the reaction of linoleic acid hydroperoxides (LOOH) with ca. 20 different amino acids and bovine serum albumin (BSA) were studied. Only the amino acids, lysine, glycine, arginine, histidine and phenylalanine, gave products with strong fluorescent properties. Products of lysine had a fluorescence intensity of ca. 10 times those of glycine and 100 times those of phenylalanine. The N-acylation of amino acids greatly reduced the fluorescence of the products of the reaction except lysine and arginine. The fluorescence of the products of the reaction of LOOH with N-acetyl BSA was only ca. 25% of the control BSA under the same conditions. It appeared that the substances formed from the reaction of LOOH with BSA were crosslinked polymers as evidenced by column chromatography and polyacrylamide gel electrophoresis. These products were insoluble in common organic solvents and their fluorescent intensities correlated well with the thiobarbituric acid (TBA) test. These observations appear to be highly important in the formation of lipofuscin substances, particularly those associated with the aging pigments which accumulate during aging in mammalian tissues.
TL;DR: A combination of vitamin E deficiency and NO2 exposure resulted in the greatest increases in lung and liver microsomal lipid peroxidation with the largest relative increases occurring in lung microsomes.
Abstract: Rat lung and liver microsomes were used to examine the effects of dietary vitamin E deficiency on membrane lipid peroxidation. Microsomes from vitamin-E-deficient rats displayed increased lipid peroxidation in comparison to microsomes from vitamin-E-supplemented controls. The extent of lipid peroxidation, as determined by measurement of thiobarbituric acid reacting materials, was enhanced by addition of reduced iron and ascorbate (or NADPH). Rats fed a vitamin-E-supplemented diet and exposed to 3 ppm NO2 for 7 days did not exhibit increases in microsomal lipid peroxidation compared to air-breathing controls. However, increases were found in microsomes prepared from rats fed a vitamin-E-deficient diet and exposed to NO2. Lung microsomes from vitamin-E-fed rats contained almost 10 times as much vitamin E as liver microsomes when expressed in terms of polyunsaturated fatty acid content. The extent of lipid peroxidation was, in turn, considerably less in lung than in liver microsomes. Lipid peroxidation in lung microsomes from vitamin-E-deficient rats was comparable to liver microsomes from vitamin-E-supplemented rats as was the content of vitamin E in these respective microsomal samples. A combination of vitamin E deficiency and NO2 exposure resulted in the greatest increases in lung and liver microsomal lipid peroxidation with the largest relative increases occurring in lung microsomes. An inverse relationship was found between the extent of lipid peroxidation and vitamin E content. Most of the peroxidation in lung microsomes appeared to proceed nonenzymatically whereas peroxidation in liver was largely enzymatic. Vitamin E appears to be assimilated by the lung during oxidant inhalation, but with dietary vitamin E deprivation, the margin for protection in lung may be less than in liver.
TL;DR: The purified human milk lipoprotein lipase showed a preferential stereospecific lipolysis of thesn-1-position of the triacylglycerol molecule.
Abstract: The fatty acid specificity of purified human milk lipoprotein lipase was studied using the C18 to C54 (total acyl carbon number) saturated and the C54 mono-, di- and triunsaturated monoacid triacylglycerols. Kinetic determinations indicated that the medium-chain triacylglycerols were better substrates than long- or very short-chain saturated triacylglycerols. The unsaturated triacylglycerols were hydrolyzed at rates comparable to that of tricaprylin with triolein having the highest rate of hydrolysis of the unsaturated species tested. The enzyme attacked the primary ester bond much more readily than the secondary ester bond. The purified human milk lipoprotein lipase showed a preferential stereospecific lipolysis of thesn-1-position of the triacylglycerol molecule.
TL;DR: Most of the individual positional isomers of monounsaturated fatty acids of varying chain length could be separated and determined in the glass capillary GC step with the exception of those isomers containing the double bond in a relatively high ω-position.
Abstract: Positional and geometrical isomers of monounsaturated long chain fatty acids were analyzed by the combination of high performance liquid chromatography (HPLC) and glass capillary gas chromatography (GC). A preparative group separation ofcis andtrans isomers of the monounsaturated fatty acid methyl esters was achieved according to chain length by reversed-phase HPLC, and using a highly sensitive interference refractive index detector. After collection of the different fractions containingcis andtrans forms of the monounsaturated fatty acid methyl esters, the fractions were analyzed for their content of positional isomers using glass capillary GC with Silar-5 CP as stationary phase. The preparative step in the HPLC was also used analytically for the determination of the ratio between thecis andtrans monounsaturated fatty acids. A comparison was made between the results obtained with the HPLC technique and the results of a GLC technique with a packed OV-275 column. There was a good correlation between the 2 techniques with a tendency to highertrans values with the HPLC technique (4%). It was shown with reference substances that 18∶1ω6-cis to ω11-cis and 18∶1ω5-trans to ω12-trans, the most common monounsaturated fatty acid isomers in partially hydrogenated vegetable oils, could be almost quantitatively recovered in the HPLC step. Most of the individual positional isomers of monounsaturated fatty acids of varying chain length could be separated and determined in the glass capillary GC step with the exception of those isomers containing the double bond in a relatively high ω-position. The relative standard deviation of the technique as determined with reference substances was better than 4%. The described technique was applied to the analysis of the isomeric monounsaturated fatty acid content in partially hydrogenated vegetable and marine oils, and about 5 samples a day could be executed.
TL;DR: The rate of oxidation and the ratio ofcis,trans/trans,trans hydroperoxides were dependent on solvent and increased with an increase in dielectric constant of solvent, and a mechanism of methyl linoleate oxidation consistent with these results is discussed.
Abstract: The effects of oxygen pressure, substrate concentration and solvent on the rate and products of oxidation of methyl linoleate were studied at 50 C with azobisisobutyronitrile as a radical initiator. The absolute and quantitative numbers for oxygen uptake, substrate disappearance, and formation of conjugated diene and hydroperoxides were measured. Under the present conditions, 4 conjugated diene hydroperoxides, 13-hydroperoxy-9-cis, 11-trans-(2a), 13-hydroperoxy-9-trans, 11-trans-(3a), 9-hydroperoxy-10-trans, 12-cis-(4a), and 9-hydroperoxy-10-trans, 12-trans-(5a) octadecadienoic acid methyl esters, were formed almost quantitatively. The rate of oxidation decreased with decreasing oxygen pressure. However, the ratio ofcis,trans totrans,trans hydroperoxides, (2a+4a)/(3a+5a), was independent of oxygen pressure, and this ratio increased with increasing methyl linoleate concentration, as found recently by Porter. Further, the rate of oxidation and the ratio ofcis,trans/trans,trans hydroperoxides were dependent on solvent and increased with an increase in dielectric constant of solvent. A mechanism of methyl linoleate oxidation consistent with these results is discussed.
TL;DR: In this system, the yield oftrans, trans hydroperoxides was much greater than that ofcis,trans isomers at all stages of autoxidation, and both trihydroxyoctadecenoate and hydroxyepoxyoctade cenoate were produced in substantial quantities.
Abstract: Autoxidation of pure soybean phosphatidylcholine liposomes at 40 C was found to proceed without an observed induction period, but otherwise, the rates of disappearance of the linoleic acid (70% of total) and linolenic acid (6% of total) followed typical autocatalytic kinetics. Incorporation of 0.05 mol % of tocopherol into the liposomes produced an induction period of about 7 hr under the condition used for the incubation. The products formed from the autoxidation of pure soybean phosphatidylcholine liposomes were mostly 9- and 13-hydroperoxyoctadecadienoates (isolated as hydroxy esters). The yield of hydroperoxides with cis,trans configuration was about the same as those with trans,trans configuration throughout incubation period. After extensive autoxidation, a large quantity of trihydroxyoctadecenoate was also produced. When a large quantity of dipalmitoyl phosphatidylcholine was incorporated into soybean phosphatidylcholine liposomes, the rate of autoxidation decreased and was found to conform to apparent first-order kinetics. In this system, the yield of trans,trans hydroperoxides was much greater than that of cis,trans isomers at all stages of autoxidation. Late in the autoxidation of the mixed liposomes, both trihydroxyoctadecenoate and hydroxyepoxyoctadecenoate were produced in substantial quantities.
TL;DR: In this paper, the oxidation products of cholesterol oxidized by different dioxygen species, hydroxyl radical, or triatomic species ozone variously implicated in biological oxidtions are compared.
Abstract: The oxidation products of cholesterol oxidized by different dioxygen species, hydroxyl radical, or triatomic species ozone variously implicated in biological oxidtions are compared. Some products are unique to the oxygen species involved, whereas others, such as the isomeric cholesterol 5,6-epoxides, are formed broadly by many oxygen species. The resolution of the isomeric cholesterol 5,6-epoxides by capillary column gas chromatography on SE-30 or SE-54 has been achieved.
TL;DR: The procedure described is efficient and most versatile, and it lends itself to the preparation of a wide range of choline phospholipids containing a glycerol, diol, or long-chain alkyl backbone and bearing various aliphatic functions.
Abstract: Choline phospholipids can be conveniently synthesized by reaction of a lipophilic alcohol, such as diacylglycerol, with 2-bromoethyl dichlorophosphate followed by nucleophilic displacement of the bromine with trimethylamine. We found that the low yields often encountered in the initial phosphorylation step are particularly due to exchange of both chlorines for alkoxy functions (triester formation) and to chlorination of the alcohol by 2-bromoethyl dichlorophosphate. However, these drawbacks can be overcome by proper choice of the reaction medium and by optimizing other reaction conditions. The procedure described is efficient and most versatile, and it lends itself to the preparation of a wide range of choline phospholipids containing a glycerol, diol, or long-chain alkyl backbone and bearing various aliphatic functions. Proton and carbon-13 nuclear magnetic resonance spectroscopy proved useful in establishing the homogeneity and structures of the synthetic intermediates and byproducts and of the choline phospholipids synthesized.
TL;DR: Six species of phytoplankton,Pseudoisochrysis paradoxa, Isochrysis galbana, MonochRYsis lutheri, Platymonas suecica, Thalassiosira fluviatilis and aChaetoceros species, were cultured in the laboratory and their sterol contents analyzed utilizing digitonin precipitation, thin layer and gas chromatography and gas Chromatography-mass spectrometry.
Abstract: Six species of phytoplankton,Pseudoisochrysis paradoxa, Isochrysis galbana, Monochrysis lutheri, Platymonas suecica, Thalassiosira fluviatilis and aChaetoceros species, were cultured in the laboratory and their sterol contents analyzed utilizing digitonin precipitation, thin layer and gas chromatography and gas chromatography-mass spectrometry. A total of 7 sterols were found in phytoplankton. The occurrence of these sterols, cholest-5-en-3β-ol, cholest-5,22-dien-3β-ol, 24-methylcholesta-5,24(28)-dien-3β-ol, 24-methylcholest-5-en-3β-ol, 24-methylcholesta-5,22-dien-3β-ol, 24-ethylcholest-5-en-3β-ol and 24-ethylcholest-5,22-dien-3β-ol, differed significantly among the various phytoplankton species. Cultures ofP. paradoxa biosynthesized both of the sterols found in this species when incubated in the presence of14C- or3H-mevalonic acid for 0.5–9 days. These sterols were cholesterol and 24-methylcholesta-5,22-dien-3β-ol. Since 5 of the sterols found in the phytoplankton commonly occur in mollusks which feed on phytoplankton, it is likely that at least some of the tissue sterols in mollusks are of dietary origin.
TL;DR: The lingual lipase in gastric aspirates from premature infants was found to be partially stereospecific forsn-3 esters of synthetic enantiometric triacylglycerols containing 18∶1 and 16∶0.
Abstract: The lingual lipase in gastric aspirates from premature infants was found to be partially stereospecific forsn-3 esters of synthetic enantiometric triacylglycerols containing 18∶1 and 16∶0 Thesn-3 ester was hydrolyzed about 4 times faster than the acid at thesn-1 position with no difference in rates between 18∶1 and 16∶0 Thesn-2 was also hydrolyzed to some extent
TL;DR: Cholesteryl stearate, oleate, linoleate and arachidonate were oxidized in solid form (at 100 C) and in a water dispersion (in the presence of potassium stearates, pH 7.5, 80 C) as discussed by the authors.
Abstract: Cholesteryl stearate, oleate, linoleate, linolenate and arachidonate were oxidized in solid form (at 100 C) and in a water dispersion (in the presence of potassium stearate, pH 7.5, 80 C). The unsaponifiable fraction was analyzed by capillary gas liquid chromatography. In the solid state, the oxidation rates of esterified cholesterol were high for stearate and oleate, low for the polyunsaturated esters and very low for free cholesterol. In water dispersion, the rates were reversed, e.g., free cholesterol oxidized more quickly than its stearic and oleic acid esters. The fatty chains in 18∶0 and 18∶1 inhibited the autoxidation of cholesterol. Hydroxylation of the cholesterol side chain only occurred during solid-state autoxidation as previously observed by others. The 20- and 25-hydroxycholesterols were never detected in the products of micellar reactions, regardless of which surfactant was used for micelle formation.