Showing papers in "Lipids in 1985"
TL;DR: The separation of non phosphorus lipids and phospholipids of rat heart using Sep-pack Silica cartridges is described and a complete partition ofNon phosphorus Lipids andospholipid is obtained.
Abstract: The separation of non phosphorus lipids and phospholipids of rat heart using Sep-pack Silica cartridges is described. No cartridge preparation is necessary before utilization. The separation of lipid extracts is very fast. A complete partition of non phosphorus lipids and phospholipid is obtained.
576 citations
TL;DR: The efficiency of the new method has been confirmed for human plasma, red blood cells and rat liver homogenate by the comparison of the yields of vitamin E, O-acyl lipid and cholesterol with the yields obtained following conventional extraction procedures.
Abstract: A new, general method for lipid extraction and measurement of vitamin E/total lipid ratios in tissue and cell samples has been developed. The new extraction procedure use a combination of sodium dodecylsulfate, ethanol andn-heptane, and is mild, clean, convenient, efficient and rapid (≤5 min). The efficiency of the new method has been confirmed for human plasma, red blood cells and rat liver homogenate by the comparison of the yields of vitamin E, O-acyl lipid and cholesterol with the yields obtained following conventional extraction procedures. Extraction efficiency also has been confirmed for multilamenllar vesicles composed of known quantities of vitamin E, egg lecithin and cholesterol.
364 citations
TL;DR: In this paper, the authors performed the thiobarbituric acid (TBA) reaction of several aldehydes and oxidized lipids in glacial acetic acid, and all the samples were freely soluble in the solvent used.
Abstract: Thiobarbituric acid (TBA) reaction of several aldehydes and oxidized lipids in glacial acetic acid was performed. All the samples were freely soluble in the solvent used. Saturated aldehydes produced a stable yellow pigment with an absorption maximum at 455 nm, a red pigment derived from malonaldehyde at 532 nm, and an orange pigment due to dienals at 495 nm. The absorbance maximum was 7–9 per μmol for saturated aldehydes, 27.5 per μmol for malonaldehyde and about 2 per μmol for dienals. Autoxidation of unoxidized lipids increased progressively in glacial acetic acid. When the TBA test was performed under nitrogen, autoxidation of unoxidized lipids was inhibited completely. While saturated aldehydes produced no yellow pigment under nitrogen, oxidized lipids produced a considerable amount of stable yellow pigment. The value for absorbance at 455 nm as a function of autoxidation time paralleled those of peroxide values. The absorbance of most oxidized lipids at 455 nm was higher than at 532 nm. Yellow pigment formation in the TBA test under nitrogen could not be ascribed to free saturated aldehydes but rather to unspecified closely related substances. The stable yellow pigment was found to be an excellent indicator of lipid oxidation.
141 citations
TL;DR: The conservation of high levels of PUFA in lipids during embryogenesis and early larval development reflects the importance of these fatty acids during development.
Abstract: The fatty acid compositions of total polar and total neutral lipids of Atlantic herring eggs and larvae were determined immediately before fertilization, after fertilization and at various times during subsequent embryonic and early larval development. Within 3 hr after fertilization the percentage of total PUFA in neutral lipid decreased from 33% to 20%, with a reciprocal increase in monoenes. Thereafter the percentage of PUFA in the neutral lipids increased progressively, attaining the original level in ripe eggs by the time of yolk sac absorption. During the larval stages the percentage of PUFA continued to increase in the neutral lipid, reaching almost 44% of the total by day 32 after fertilization, although it was reduced to 32% by day 36. The percentage of monoenes in the neutral lipid displayed a progressive decrease during the whole period of development from 3 hr after fertilization. Throughout all the developmental periods the fatty acid composition of total polar lipids remained essentially constant. The polar lipids of the yolk sac displayed virtually the same fatty acid composition as the larval bodies, but the neutral lipids of the yolk sac were low in PUFA compared to the larval bodies. The results are discussed with reference to changes in lipid class composition during development. The conservation of high levels of PUFA in lipids during embryogenesis and early larval development reflects the importance of these fatty acids during development.
135 citations
TL;DR: The lipid class compositions of Atlantic herring eggs and larvae were determined immediately before fertilization, after fertilization and at various times during subsequent embryonic and early larval development, finding that the total lipid content decreased gradually during embryogenesis and in particular during larvalDevelopment.
Abstract: The lipid class compositions of Atlantic herring eggs and larvae were determined immediately before fertilization, after fertilization and at various times during subsequent embryonic and early larval development. Total lipid constituted 15% of the dry wt of ripe eggs, 70% of the total lipid being polar lipid with phosphatidylcholine (PC) accounting for almost 90% of the polar lipid. In general, the total lipid content decreased gradually during embryogenesis and in particular during larval development. Within 3 hr after fertilization the relative percentage of neutral lipid decreased slightly. This was followed by a general decrease in polar lipid which, by the stage of yolk sac absorption, was reduced to 52% of the total lipid. The decreased percentage of polar lipid was due entirely to a decrease in PC, which was reduced to 66% of the polar lipids at the stage of yolk sac absorption. The accompanying increase in the percentage of neutral lipids was mainly due to increased percentages of triacylglycerols (TAG) up to yolk sac absorption and cholesterol esters in the larval stages. During the first 4 days after hatching, phospholipids and to a lesser extent cholesterol were preferentially depleted in the yolk sacs, which also had higher levels of free fatty acids. The results are discussed in relation to possible roles of different lipids during embryonic and early larval development.
122 citations
TL;DR: Levels of triacylglycerol decreased markedly during development, but there were few changes in fatty acid composition, indicating a non-selective utilization of fatty acids.
Abstract: Lipid class and fatty acid analyses were carried out on developing salmon eggs at four clearly defined pre-feeding stages, namely, fertilization, eyed egg stage (50 days), hatching (yolk sac fry, 98 days) and swim up fry (138 days).
109 citations
TL;DR: These SM properties might contribute to the organism's resistance to digestion in the hydrolytic environs of both its insect vector and mammalian hosts.
Abstract: Constituent lipids of surface membranes (SM) isolated fromLeishmania donovani promastigotes were analyzed and compared with those obtained from whole cells and an isolated kinetoplast-mitochondrion fraction (KM). On a dry weight basis, the total extractable lipids constituted ≈47%, 12% and 24% of the SM, cells and KM, respectively. The total lipids of SM, cells and KM all were composed of ≈70% phospholipids (PL), 20–25% neutral lipids and 5–10% glycolipids. Sterols and diglycerides composed 60% and 30%, respectively, of the various neutral lipid fractions. Several mannose- and galactose-containing glycolipids were fractionated but not identified. The glycolipid fractions from cells and SM had demonstrable antigenic activities with rabbit anti-SM sera. Striking quantitative differences were apparent between the PL profiles of the 3 cellular components examined. The PL of SM, whole cells and KM, respectively, were composed of: 15%, 51% and 24% phosphatidylcholine; 37%, 13% and 11% phosphatidylethanolamine (PE); 18%, 10% and 14% phosphatidylinositol; 10%, 1% and 4% phosphatidylserine and traces of cardiolipin, phosphatidylglycerol and phosphatidic acid. An unknown PL containing sphingosine, choline and vicinal hydroxyl groups but no free amino moieties made up ≈19% of the PL of SM and whole cells, but it constituted ≈27% of the PL of KM. The PL side chain constituents of whole cells and SM were composed mainly of longchain fatty acids (C18–20). Further, over 50% of the PE of SM was in the alkyl and alK-1-enyl ether forms. These SM properties might contribute to the organism's resistance to digestion in the hydrolytic environs of both its insect vector and mammalian hosts.
106 citations
TL;DR: In this paper, secondary autoxidation products (SP) of linoleic acid were administered to a group of 5 rats, and excretions of radioactive substances in feces, urine and respiration were measured and compared with excretion from rats fed linolenic acid and its hydroperoxides.
Abstract: Incorporation of secondary autoxidation products (SP) of linoleic acid into the rat body was investigated. Radioactive SP was administered orally to a group of 5 rats, and excretions of radioactive substances in feces, urine and respiration were measured and compared with excretions from rats fed linoleic acid and its hydroperoxides. The SP-fed group excreted 45% and the other groups about 10% of the administered radioactivity through feces. Urinary excretion accounted for 52% of activity ingested in the SP group and less than 30% in the other groups. The 14CO2 produced in each group was about 25% of the ingested activity. Incorporation of the radioactive substances of SP into tissues and organs was measured periodically after administration of a single dose. The radioactive substances accumulated in the liver between 12-24 hr after administration and accounted for 2.6% of the total amount given, the highest level of all tissues and organs. This accumulation led to an elevation of serum transaminase activities, an increase in hepatic lipid peroxide, as determined by thiobarbituric acid test, and a slight hypertrophy of liver (1.5-fold). Therefore, absorbed SP appeared to contribute to the deleterious condition of the liver.
99 citations
TL;DR: In this paper, four diets which differed in fatty acid composition were provided for five months each to a group of 24 healthy nun volunteers, each of which contained 54% carbohydrates, 16% proteins and 30% lipids One third of the lipid part remained unchanged during the whole study, and two-thirds were modified during each period.
Abstract: Four diets which differed in fatty acid composition were provided for five months each to a group of 24 healthy nun volunteers The diets contained 54% carbohydrates, 16% proteins and 30% lipids One-third of the lipid part remained unchanged during the whole study, and two-thirds were modified during each period For this latter portion, one of the following dietary fats was used: sunflower oil, peanut oil, low erucic acid rapeseed (LEAR) oil or milk fats This procedure allowed an evaluation of the effects of various amounts of dietary linoleic acid (C18:2 omega 6) and alpha-linolenic acid (C18:3 omega 3) on the serum level of their metabolites A diet providing a large amount of linoleic acid (14% of the total caloric intake) resulted in low levels of dihomo-gamma-linolenic acid (C20:3 omega 6) and arachidonic acid (C20:4 omega 6) in serum phospholipids and cholesteryl esters A diet providing a small amount of linoleic acid (06% to 13% of the total caloric intake) induced high levels of omega 6 fatty acid derivatives Intermediate serum levels of C20:3 omega 6 and C20:4 omega 6 were found with a linoleic acid supply of about 65% of the total caloric intake Serum levels of omega 6 metabolites were not different after two diets providing a similar supply of C18:2 omega 6 (45% to 65% of the total caloric intake), although in one of them the supply of C18:3 omega 3 was higher (15% for LEAR oil versus 013% for peanut oil)(ABSTRACT TRUNCATED AT 250 WORDS)
97 citations
TL;DR: The results of gas chromatography mass spectrometry revealed that hydroxy fatty acid components of the hydroxy derivatives were derived from isomeric hydroperoxides of oleic acid, linoleic Acid, arachidonic acid and docosahexanoic acid.
Abstract: A convenient method for the preparation of hydroperoxy and hydroxy derivatives of phosphatidylcholine (PC) and phosphatidylethanolamine (PE) is described. PC and PE obtained from rat liver were oxidized with singlet oxygen by using methylene blue as the photosensitizer, and their hydroperoxides were isolated with the aid of reverse phase liquid chromatography. The hydroxy derivatives were obtained by reducing the hydroperoxides with sodium borohydride. The results of gas chromatography mass spectrometry revealed that hydroxy fatty acid components of the hydroxy derivatives were derived from isomeric hydroperoxides of oleic acid, linoleic acid, arachidonic acid and docosahexanoic acid. Normal phase high performance liquid chromatography did not separate the hydroperoxy and hydroxy derivatives from the respective unoxidized phospholipids, although unoxidized PC and PE were separated from each other. However, the hydroperoxy and hydroxy derivatives could be distinguished from unoxidized phospholipid species on reversed phase thin layer chromatography.
89 citations
TL;DR: In this paper, a two-step development procedure with partial scanning after the first development resolves seawater lipids into seven classes is described, and the low concentration in seawater of some of these classes necessitates calibration close to the detection limit of the FID.
Abstract: A two-step development procedure with partial scanning after the first development resolves seawater lipids into seven classes. The low concentration in seawater of some of these classes necessitates calibration close to the detection limit of the flame ionization detector (FID). From 0.2 to 5.0 μg the FID response usually is curvilinear, necessitating multilevel calibration. Interrod precision was poor for most of this range, and this prompted an investigation of factors affecting FID responses.
TL;DR: Activated metmyoglobin by H2O2 initiates oxidation of microsomal unsaturated fatty acids, β-carotene and methional but not formate and lipid peroxidation was not inhibited by catalase.
Abstract: Activated metmyoglobin (MetMb) by H2O2 initiates oxidation of microsomal unsaturated fatty acids, beta-carotene and methional but not formate. Lipid peroxidation by activated MetMb was not inhibited by catalase. The activated species which initiates lipid peroxidation appears to be a porphyrin cation radical, PFeIV=O, and not a hydroxyl radical.
TL;DR: A rapid, sensitive and convenient fluorescent assay was developed to screen for lipase activity with several advantages: nmoles 4 MU/ml/hr are measured allowing the detection of very low lipolytic activity; multiple samples may be simultaneously assayed, and only a brief incubation period is required.
Abstract: A rapid, sensitive and convenient fluorescent assay was developed to screen for lipase activity. The non-fluorescent substrate, 4-methylumbelliferyl butyrate (4-MUB), solubilized in either liposomal dispersions or bile salt/lecithin mixed micelles, is hydrolyzed to butyric acid and the highly fluorescent compound, 4-methylumbelliferone (4-MU). Assays are run at 37 C for 10 min, terminated, and the changes in fluorescence quantitated with a Turner III fluorometer. Both lingual and pancreatic lipases exhibit activity against this artificial substrate. The assay has several advantages: nmoles 4 MU/ml/hr are measured allowing the detection of very low lipolytic activity; multiple samples may be simultaneously assayed, and only a brief incubation period is required.
Abstract: The13C NMR spectrum of the carbonyl carbons of the acyl groups of triacylglycerols of palm oil has been shown to give the composition of saturated, oleic and linoleic acyl groups at the 1,3-positions and at the 2-position of the glycerol moiety. Except for the lack of differentiation of the saturated fatty acids, the13C NMR technique provides the same information as the tedious enzymatic hydrolysis cum fatty acid analysis. The carbonyl carbon of the linolenic acyl group (18∶3,[cis, cis, cis]-9, 12, 15) has a chemical shift which is only 0.005 ppm to low frequency of that of the linoleic acyl group (18∶2,[cis, cis]-9, 12), so that the two resonances may not be distinguishable (or resolved) even at a high magnetic field.
TL;DR: Two types of triesters comprising approximately 1% of total steer meibomian lipids have been isolated but incompletely characterized and gave fatty acids, α-hydroxy fatty acids and α,ω-diols in what appears to be a complex mixture of several triesters.
Abstract: Three groups of diesters have been isolated and identified in the lipids of steer meibomian glands. The first group, designated as alpha Type I, with the abbreviated formula FA-alpha OHFA-FAlc, consisted of alpha-hydroxy fatty acids esterified to fatty acids and fatty alcohols in the approximate molar ratio 1:1:1. The second group, designated as omega Type I-St, with the abbreviated formula FA-omega OHFA-St, consisted of omega-hydroxy fatty acids esterified to fatty acids and sterols in the approximate molar ratio 1:1:1. The third group, designated as alpha, omega Type II, with the abbreviated formula FA-alpha, omega diol-FA, consisted of alpha, omega-diols esterified to 2 moles of fatty acids. The sum of the different diesters comprised about 9% of total steer meibomian lipids. Capillary GLC of the fatty acids of alpha Type I diesters showed the fatty acids to be a family with a two-cluster profile, one at C12 to C20 and the other at C21 to C31, with anteiso chains predominating. Fatty acids from omega Type I-St and alpha, omega Type II diesters gave mainly a one-cluster profile in the short chain region with prominent anteiso and C18:1 peaks. Fatty alcohols of alpha Type I diesters were mainly long chain, C23 to C30, with anteiso chains predominating, while the alpha-hydroxy fatty acids were short chain C13 to C18 acids with C16 predominating. The sterols in diesters omega Type I-St were cholesterol (approximately 60%), delta 7 cholestenol (approximately 35%) and an unidentified compound (approximately 5%) with a GLC retention time slightly longer than delta 7 cholestenol on SE-30 phase. The omega-hydroxy fatty acids and alpha, omega-diols both were of exceedingly long chain lengths, C29-C38, and showed similar GLC profiles. Two types of triesters comprising approximately 1% of total steer meibomian lipids have been isolated but incompletely characterized. In terms of molar ratios, one group of triesters gave fatty acids:omega-hydroxy fatty acids:alpha-hydroxy fatty acids:sterols + fatty alcohols as approximately 1:1:1:1. The other contained fatty acids, alpha-hydroxy fatty acids and alpha, omega-diols in what appears to be a complex mixture of several triesters. Diesters omega Type I and alpha, omega Type II also were found in human meibum. Hitherto these two diesters have not been found in any animal tissue.
TL;DR: Properties of a heat labile, nondialyzable cytosolic factor which prevents lipid peroxidation in membranous organelles are described, and it appears to be a potent and ubiquitous system for stabilizing cell membranes against oxidative damage.
Abstract: Properties of a heat labile, nondialyzable cytosolic factor which prevents lipid peroxidation in membranous organelles are described. The factor is present in liver and other animal tissues, and its capacity to inhibit lipid peroxidation in membranes subjected to oxidative stress is greatly potentiated by glutathione (GSH), although GSH by itself has no inhibitory effect on lipid peroxidation. The data obtained thus far indicate that one or more sulfhydryl groups associated with the factor is required for the inhibition. The mechanism by which lipid peroxidation is inhibited must involve prevention of initiation of peroxidation in the membranes, presumably by a process requiring one or more sulfhydryl groups associated with the heat labile factor. The latter appears to be protected by GSH while the factor is exerting its inhibitory effect on lipid peroxidation. The factor is not one of the known GSH-dependent enzymes, and appears to be a potent and ubiquitous system for stabilizing cell membranes against oxidative damage.
TL;DR: The present method will facilitate synthesis of isomerically pure diradylph phospholipids by providing homogeneous lysophospholipid precursors and help simplify the quantitative analysis of unsaturated lysphospholIPid species.
Abstract: A reverse-phase high performance liquid chromatography (HPLC) method was developed which resolved isomers of lysophosphatidylcholine (LPC) differing in the location of the aliphatic chain (sn-1 or sn-2 position) and the position (delta 6 or delta 9) or geometric configuration (cis or trans) of the olefin group in monounsaturated species. LPC isomers containing an acyl substituent at the sn-2 position eluted before their 1-acyl-sn-glycero-3-phosphocholine (1-acyl LPC) counterparts. The retention times of both the sn-1 and sn-2 isomers of monounsaturated species increased in the order delta 9-cis less than delta 9-trans less than delta 6-cis. The integrated ultraviolet absorbance (203 nm) in binary mixtures of the delta 9-cis and delta 6-cis 2-acyl lysophospholipid isomers correlated with the lipid phosphorus content of corresponding column eluates (r = 0.994). Thus, the present method will facilitate synthesis of isomerically pure diradylphospholipids by providing homogeneous lysophospholipid precursors and help simplify the quantitative analysis of unsaturated lysophospholipid species.
TL;DR: The temporal correlation between the early burst of PtdIns(4,5)P2 and Ins(1,4, 5)P3 formation and the transient increase in intracellular free calcium known to occur in the fertilized egg suggest that the production of PTDIns( 4,5]P 2 and ultimately Ins( 1,4-5) P3 may be associated with calcium mobilization within the egg.
Abstract: Fertilization of the sea urchin egg results in a transient decline in the amount of phosphatidylinositol (PI) to a level equal to about 50% of that present in the unfertilized egg. This response begins as early as 15 seconds after insemination. The level of PI reaches a minimum at 30 seconds post-insemination, and returns to the original value between 2 and 5 min later. Pulse labelling studies with 32PO4 and [3H]-inositol showed that the incorporation of these two isotopes into 1-(3-sn-phosphatidyl)-L-myo-inositol 4,5-biphosphate [PtdIns(4,5)P2] increased as much as 50% within one minute after insemination. This suggests that at least part of the reduction in PI levels represents the phosphorylation of PI to form PtdIns(4,5)P2. We also found that the production of [3H]-labelled 1D-myoinositol 1,4,5 triphosphate [Ins(1,4,5)P3] present in the trichloroacetic acid (TCA) soluble fraction of eggs increased over five-fold during the first 10 min post insemination. The temporal correlation between the early burst of PtdIns(4,5)P2 and Ins(1,4,5)P3 formation and the transient increase in intracellular free calcium known to occur in the fertilized egg suggest that the production of PtdIns(4,5)P2 and ultimately Ins(1,4,5)P3 may be associated with calcium mobilization within the egg.
TL;DR: It is suggested that lysolecithin absorption results in a rapid supersaturation with cholesterol leading to cholesterol absorption, and with larger micells some factor other than micellar size and cholesterol content of the micelles is important.
Abstract: The aim of our study was to define the mechanism by which cholesterol uptake is inhibited by lecithin but not by lysolecithin. The work compared the cholesterol uptake by everted rat jejunal sacs from bile salt-lecithin-cholesterol or bile salt-lysolecithin-cholesterol micelles. The micellar size and the cholesterol saturation were measured. The size or molecular weight increases when the lecithin concentration rises, and the cholesterol uptake decreases and leads to zero when the micelles contain more than 30% lecithin. The size of bile salt-lysolecithin-cholesterol micelles is smaller than that of lecithin micelles in comparable molar ratios. Consistent with this result is the fact that, for a given phospholipid concentration, cholesterol uptake is greater in the presence of lysolecithin than in the presence of lecithin. The diffusion rate of the micelles through the unstirred water layer decreases when micellar size increases. However, the comparison of uptakes from lecithin or lysolecithin micelles similar in size and in cholesterol saturation showed that the cholesterol uptake is still lower for lecithin micelles. This shows that with larger micelles some factor other than micellar size and cholesterol content of the micelles is important. We observe that lysolecithin absorption is 15-fold greater than lecithin absorption. We suggest that lysolecithin absorption results in a rapid supersaturation with cholesterol leading to cholesterol absorption.
TL;DR: Tissue fatty acid analyses support the hypothesis that the decrease is due in part to depression of arachidonate and accumulation of eicosatrienoate, and evidence for the obvious mechanism that alterations in precursor fatty acid composition are a possible explanation is fragmentary and inconsistent.
Abstract: Essential fatty acid deficiency consistently depresses eicosanoid (prostaglandin E2, F2, and I2 and thromboxane) biosynthesis independent of sampling protocols. Tissue fatty acid analyses support the hypothesis that the decrease is due in part to depression of arachidonate and accumulation of eicosatrienoate (n−9). Research on the alteration of eicosanoid biosynthesis by dietary linoleate supplementation is reviewed extensively. Responses of whole blood, lung, liver and heart eicosanoid synthesis to feeding eight concentrations of dietary linoleate between 0 and 27 energy percent are reported. It is concluded that stimulation, depression and no change in eicosanoid production could be equally well documented as a response to linoleate supplementation. Evidence for the obvious mechanism that alterations in precursor fatty acid composition are a possible explanation is fragmentary and inconsistent. The appropriate sampling techniques appear not to be established at this time and most likely are species, gender and tissue specific.
TL;DR: In this paper, the authors studied three stages of development of oil palm (E. guineensis) fruits and found that the mesocarp contained very little oil and incorporated acetate into polar lipids.
Abstract: Oil palm (E. guineensis) fruits at three stages of development were studied. At week 12–13 after anthesis, the endosperm had started accumulating oil and tissue slices incorporated [1-14C] acetate into fatty acids which resembled those found in the mature endosperm. The mesocarp contained very little oil and incorporated acetate into polar lipids. At week 16–17, the mesocarp started to accumulate oil; this was reflected in the [14C] lipid products from acetate incubation. At or just prior to this stage, an increase in the endogenous linoleic and linolenic acid content and the increase in fruit size indicated cellular growth in the mesocarp tissue. At week 20–21 the fruit was ripe, and both endosperm and mesocarp tissues were filled with storage oil. [14C] Fatty acids synthesized from acetate by mesocarp slices at this stage were the same as the endogenous storage fatty acids in bothE. guineensis andE. oleifera. A very weak fatty acid synthesizing activity was seen in the mature endosperm, but the products had no relationship to the storage lipid.
TL;DR: In this paper, a gradient elution reversed phase HPLC system with a mass detector was investigated for the separation of triglycerides, and a gradient based on a ternary eluent mixture was suggested.
Abstract: A gradient elution reversed phase HPLC system with a mass detector was investigated for the separation of triglycerides. A gradient based on a ternary eluent mixture is suggested. The detector was investigated in terms of linearity, reproducibility and relative response. The separation of soybean oil and some other natural triglyceride mixtures is demonstrated.
TL;DR: The results presented here suggest certain degrees of dissimilarity between the first (C18∶1→C20∶ 1→C22∵1) and second elongation systems.
Abstract: In the presence of NADPH and malonyl-CoA, the cell-free extract of developingBrassica juncea seeds catalyzes the elongation of14C-oleoyl-CoA to radioactive C20∶1 and C22∶1. The elongation of C18∶1 to C20∶1 shows no marked preference for NADPH or NADH. On the other hand, the elongation of C20∶1 to C22∶1 exhibits a pronounced preference for NADPH. Moreover, the latter elongation system (C20∶1→C22∶1) is more sensitive to inhibition by trichloroacetate and sodium metabisulfite. Inclusion of polyvinylpolypyrrolidone in the grinding buffer for preparation of the cell-free extract enhances the elongation activity by 5–6 fold.14C-Stearoyl-CoA, but not14C-palmitoyl-CoA, also is elongated by this system. The results presented here suggest certain degrees of dissimilarity between the first (C18∶1→C20∶1) and second elongation (C20∶1→C22∶1) systems.
TL;DR: The predominant 4-desmethylsterols from the leaves of 13 species in eight genera of the family Chenopodiaceae are 24α-ethylsterols, and the saturated side chain analogues predominate with more than 70% of the 24-ethylcholesta-7,24(28)Z-dien-3β-ol in eight species.
Abstract: The predominant 4-desmethylsterols from the leaves of 13 species in eight genera of the family Chenopodiaceae are 24α-ethylsterols. In four species,Chenopodium ambrosioides L.,C. rubrum L.,Salicornia europaea L. andS. bigelovii Torr., the C-22(23) double bond is introduced into more than 70% of the 24α-ethylsterols producing spinasterol (24α-ethylcholesta-7,22E-dien-3β-ol) in the first two species and mixtures of spinasterol and stigmasterol (24α-ethylcholesta-5,22E-dien-3β-ol) in the latter species. The saturated side chain analogues predominate with more than 70% of the 24α-ethylsterols in eight species.Salsola kali L.,Suaeda linearis (Ell.) Moq.,Kochia scoparia (L.) Roth., andBassia hirsute (L.) Aschers. synthesize sitosterol (24α-ethylcholest-5-en-3β-ol), andAtriplex arenaria Nutt.,C. album L.,C. urbicum L. andC. leptophyllum Nutt. possess mixtures of sitosterol and 22-dihydrospinasterol (24α-ethylcholest-7-en-3β-ol). Sitostanol (24α-ethyl-5α-cholestan-3β-ol) was isolated fromSuaeda linearis as an 18% component of the total 4-desmethylsterol and in lesser amounts from four other species. In all species synthesizing 24-ethyl-Δ5-sterols, a 24ξ-methylcholest-5-en-3β-ol was also present at 1.0–20% of the total 4-desmethylsterol. Avenasterol [24-ethylcholesta-7,24(28)Z-dien-3β-ol], isofucosterol [24-ethylcholesta-5,24(28)Z-dien-3β-ol), cholesterol (cholest-5-en-3β-ol) and 24ξ-methyl-5α-cholestan-3β-ol also were isolated from several species. Species in the family Chenopodiaceae and the type genusChenopodium may be categorized into one of three groups based on sterol biosynthesis: the Δ7-sterol producers; the Δ5-sterol producers, and those producing mixtures of both Δ7- and Δ5-sterols in relatively fixed percentage compositions.
TL;DR: A semisynthetic diet fed to growing male rats resulted in a selective alteration of the production of vascular eicosanoids compared to the values found in rats fed a diet containing a fresh mixture of polyunsaturated oils.
Abstract: A semisynthetic diet containing adequate amounts of vitamin E and 10% (w/w) of a mixture of polyunsaturated oils subjected to heating and characterized by elevated indexes of thermal alteration (polar component, dimer triglyceride, altered triglyceride contents and reduced α-tocopherol levels) was fed to growing male rats for a period of eight weeks. It resulted in a selective alteration of the production of vascular eicosanoids (elevation of platelet thromboxane formation and decrease of vascular prostacyclin release) compared to the values found in rats fed a diet containing a fresh mixture of polyunsaturated oils. Major nutritional parameters, plasma lipids and the fatty acid profiles of plasma, liver and heart lipids were not different in the two groups of animals. Supplementation of an excess vitamin E (300 mg/kg) to the diet containing heated fat neutralized the adverse effects of heated fat on vascular eicosanoid production.
TL;DR: The observed levels of desaturation in the yolk sac membrane are capable of making a conbryonic liver, the requirement for which does not appear to be satisfied by the yolks, but with the approach of hatching the role is taken over by the embryonic tissues.
Abstract: An investigation has been made to correlate the activities of the Δ9- and Δ6-long chain fatty acid desaturation systems with the increased levels of oleic and arachidonic acids in the liver relative to the yolk sac membrane of the chick embryo during the last week of development. The membrane exhibited high levels of both stearic and linoleic acid desaturation in the early stages of yolk lipid mobilization, the activities of both enzyme systems decreasing with the approach of hatching. Stearic acid desaturation in the liver also decreased with the approach of hatching, but linoleic acid desaturation increased. The observed levels of desaturation in the yolk sac membrane are capable of making a conbryonic liver, the requirement for which does not appear to be satisfied by the yolk lipids. With the approach of hatching and the functional regression of the yolk sac membrane, the role is taken over by the embryonic tissues.
TL;DR: Steryl esters, phytyl esters and triacylglycerols of a naturally occurring freshwater dinoflagellate,Peridinium lomnickii, were identified using capillary gas chromatography-mass spectrometry (GC-MS) comparison with authentic compounds.
Abstract: Steryl esters, phytyl esters and triacylglycerols of a naturally occurring freshwater dinoflagellate,Peridinium lomnickii, were identified using capillary gas chromatography-mass spectrometry (GC-MS). Steryl esters differing in degree of unsaturation were separated, prior to analysis, by argentation thin layer chromatography. 5α(H)-Cholestanol was more dominant, relative to 4α-methylstanols, in steryl esters than in the free sterols, but the same sterol moieties occurred in both fractions. Monoenoic fatty acids were enriched in the steryl esters relative to the free fatty acids. Major acyl groups in steryl esters were 16∶0 or 20∶1, with smaller amounts of 14∶0 and 18∶1. In triacylglycerols the acyl moieties were 14∶0, 16∶0, 18∶1, 16∶1 and 12∶0, in order of decreasing abundance. Phytyl esters, previously inferred to occur in a marine dinoflagellate only by analysis of transesterified products, were identified by GC-MS comparison with authentic compounds. Direct analysis of these esterified lipids has not been reported for freshwater phytoplankton. The 4α-methylstanyl esters, 5α(H)-cholestan-3β-yl esters and phytyl esters occurring inP. lomnickii are further features in common with marine dinoflagellates, additional to the 4α-methylsterols reported previously.
TL;DR: Results indicate that RI detection is very useful in the nmole range for the quantitative analysis among the molecular species containing disaturated species.
Abstract: A high-performance liquid chromatographic (HPLC) separation of diacylglycerol acetates to quantitatite disaturated species of lung phosphatidylcholine (PC) was studied. The diacylglycerol acetates were applied on a reversed phase column, eluted by an isocratic solvent, acetonitrile/isopropanol/water (35:15:1, v/v/v) at a flow rate of 1 ml/min, and detected by differential refractometry (RI). This isocratic HPLC method was useful to separate disaturated species from the others of lung PC.
TL;DR: The phospholipids of the sponge Polymastia gleneni contain saturated long chain (C22–30)-acetoxy fatty acids and their structures were assigned based on chromatographic and spectrometric data as well as comparison with a synthetic sample.
Abstract: The phospholipids of the spongePolymastia gleneni contain saturated long chain (C22–30)-acetoxy fatty acids. Their structures were assigned based on chromatographic and spectrometric data as well as comparison with a synthetic sample. The use of capillary gas chromatography combined with chemical ionization and electron impact mass spectrometry was instrumental in the eludication of structures, since only a very small amount of crude lipids was available.
TL;DR: It is concluded that platelet lipoxygenation of eicosaenoic acids appears peroxide-dependent, especially for apparent poor substrates like EPA, which might be relevant in respect to 12-HPETE, which is the main hydroperoxy derivative to be produced during platelet activation.
Abstract: Human platelet lipoxygenase activity toward several eicosaenoic acids was measured in intact cells as well as in subcellular fractions (cytosol and membranes). In whole platelets, the lipoxygenation of eicosaenoic acids was enhanced greatly by high concentrations of aspirin, which partially inhibit the peroxidase activity associated with the pathway. The lipoxygenation also was increased by arachidonic acid (AA) or its lipoxygenase product, 12-hydroxyperoxy-eicosatetraenoic acid (12-HPETE). Similarly, prostanoid precursors, dihomogammalinolenic (DHLA) and eicosapentaenoic (EPA) acids also were better converted by cyclooxygenase in the presence of AA or 12-HPETE. Among the eicosaenoic acids tested, EPA oxygenation was affected most.