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1.
Ether lipid content and fatty acid distribution in rabbit polymorphonuclear neutrophil phospholipids
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. 相似文献
2.
Minimal deviation hepatoma 7288 C cells were cultured on media containing 25% serum to the confluent stage. The growth media was replaced with serumfree media containing 1-14C-palmitate, and incubations were continued for 0.75, 1.5, 3, 6, 12, and 24 hr. The distribution of radioactivity among the major neutral lipids and phosphoglycerides was determined for cells and culture media. Radioactivity in individual fatty acids of cellular triglyceride, phosphatidylcholine, and phosphatidylethanolamine also was determined. After 24 hr, more than 95% of the administered radioactivity was recovered in neutral and phosphoglycerides, indicating that only a small amount of the fatty acid was oxidized. At any time period examined, over 80% of the incorporated radioactivity was found in triglyceride, phosphatidylcholine, and phosphatidylethanolamine. Incorporation of the label into cellular triglyceride and phosphatidylcholine plateaued at 12 hr, whereas incorporation of radioactivity into phosphatidylethanolamine still was increasing at 24 hr. In contrast, during the entire incubation period the relative distribution of14C among esterified lipid classes in the culture media remained constant. Elongation of palmitic acid to stearic acid and its subsequent desaturation to oleic acid suggests that these cells possess an active elongation and monoenoic desaturation system. Labeled glycerol ether diesters were not detected in the cells or culture media. Positional distribution of the14C label in the triglyceride and phosphatidylcholine suggests that minimal deviation hepatoma cells do not exhibit diglyceride selectivity in the biosynthesis of these two lipid classes. 相似文献
3.
Hsiang Ju Lin M. S. F. Lie Ken Jie Clara Lai Hing Lee Daniel Hong Seng Lee 《Lipids》1977,12(7):620-625
A comparison of human adult and fetal adrenals with respect to their levels of glyceryl ether lipids and other lipid components
is reported. Fetal glands contained significantly lower levels of alk-1-enyl phosphoglycerides and of cholesterol. Neutral
glyceryl ether diesters, and ethanolamine and choline phosphoglycerides were isolated from adult adrenal tissue. The composition
of theO-alkyl glycerol groups in these lipid fractions was obtained by means of gas chromatography of the trimethylsilyl ethers and
diacetyl derivatives;O-alk-1-enyl glycerols were analyzed as their diacetates. About one-half of the alkyl and alk-1-enyl glycerol moieties present
in glyceryl ether diesters contained hydrocarbon side chains with 20, 22, or 24 carbon atoms. Long hydrocarbon chains (C19–24) were also found in theO-alkyl glycerol moieties present in the total lipids of fetal adrenals. 相似文献
4.
Long chain alcohols were detected in developing rat brain at ages ranging from 5 to 40 days. They were at their highest level
of 0.0109% of the total lipids at the age of 10 days and decreased to 0.0036% at the age of 40 days. They consisted mainly
of hexadecanol, octadecanol, octadecenol, eicosanol, docosanol, and tetracosanol. The fact that substantial amounts of fatty
alcohols having more than 20 carbon atoms were present in myelinating rat brain indicated a chain length specificity in their
utilization for0-alkyl and0-alk-1-enyl glycerolipid biosynthesis. 相似文献
5.
Edward N. Lambremont 《Lipids》1972,7(8):528-533
When14C-labeled acetate, fatty acids or fatty alcohols were injected into or fed to the tobacco budworm, acyl, alkyl and alk-1-enyl
moieties of the phospholipids incorporated radioactivity. Fatty acids were the principal precursor in acyl bond formation
and fatty alcohols in the synthesis of alkyl and alk-1-enyl glyceryl ethers. Detailed analysis of the etherlinked phosphoglycerides
revealed that most of the radioactivity was in the ethanolamine phosphoglycerides, and very little14C was found in the choline phosphoglycerides. In experiments of a short duration, the alkyl glyceryl ethers incorporated more
radioactivity than the alk-1-enyl glyceryl ethers. The reverse was found with long term experiments, when the alk-1-enyl ethers
had higher radioactivity. In addition to demonstrating the synthesis of ether-linked ethanolamine phosphoglycerides, the data
suggested that fatty alcohols and acids were interconverted by insects and that the alk-1-enyl ethers were derived from the
alkyl ethers.
Presented at the AOCS Meeting, Houston, May 1971.
The following abbreviations and terminology will be used: PE, PC, PI and PS for the generic terms ethanolamine, choline, inositol
and serine phosphoglycerides, respectfully. Alkyl glyceryl ether for 1-alkyl-2-acyl-sn-glycerol-3-phosphoryl-, and alk-1-enyl glyceryl ether for 1-alk-1′-enyl-2-acyl-sn-glycerol-3-phosphoryl-(commonly called plasmalogen). These are adapted from the tentative rules published inJ. Lipid Res. 8:522–528 (1967). 相似文献
6.
Specific differences between the acyl composition of lipids on the helminthParatenuisentis ambiguus and its host eel, as shown previously, prompted us to study the lipid metabolism in this intestinal fish parasite. Adults
and larvae ofP. ambiguus were fed various lipid precursors, e.g., fatty acids, long-chain alcohols and 1-O-alkylglycerols, which may occur as common nutrients of intestinal parasites. Incorporation of [1-14C]palmitic acid into neutral and polar lipids was found to be similar under aerobic and near-anaerobic conditions. In adult
parasites maintained in culture medium supplemented with glucose, [1-14C]palmitic acid was incorporated mainly into triacylglycerols and phosphatidylcholines, whereas [1-14C]oleic acid was incorporated preferentially into triacylglycerols. In fasted adults, as well as in larvae, [1-14C]oleic acid was mainly transferred to phosphatidylcholines. Lipolytic activity was detected in adult parasites that had been
incubated with radioactive trioleoylglycerol. [1-14C]Hexadecan-1-ol was oxidized inP. ambiguus at a high rate to labeled palmitic acid, which was incorporated into various lipid classes ofP. ambiguus. Small but significant proportions of radioactivity from hexadecan-1-ol were incorporated into ether glycerolipids of the
parasite. A more direct precursor in ether glycerolipid metabolism, i.e.,rac-1-O-[1′-14C] hexadecylglycerol, was incorporated into alkyl and 1′-alkenyl moieties of choline and etha-nolamine etherglycerophospholipids
ofP. ambiguus in high yield. High proportions of labeled diacylglycerols, triacylglycerols and steryl esters were detected in surface lipids
as well as lipid extracts of the culture media after incubation ofP. ambiguus with [1-14C]palmitic or [1-14C]oleic acids. The results suggest that palmitic acid and oleic acid are incorporated into neutral and polar lipids ofP. ambiguus maintained in glucose medium quite differently with oleic acid showing a strong preference for triacylglycerols. However,
the incorporation of palmitic acid in glucose-fed parasites was similar to that of oleic acid in fasted parasites, as well
as in larvae. This may be explained by partial fatty acid depletion in fasted worms and rapid cell division in larvae, respectively. 相似文献
7.
A mixture ofcis-9-[1-14C] octadecenol and [1-14C] docosanol was injected into the brains of 19-day-old rats, and incorporation of radioactivity into brain lipids was determined
after 3, 12, and 24 hr. Both alcohols were metabolized by the brain but at different rates; each was oxidized to the corresponding
fatty acid, but oleic acid was more radily incorporated into polar lipids. Substantial amounts of radioactivity were incorporated
into 18∶1 alkyl and alk-1-enyl moieties of the ethanolamine phosphoglycerides and into 18∶1 alkyl moieties of the choline
phosphoglycerides. Even after the disappearance of the 18∶1 alcohol from the substrate mixture (12 hr), the 22∶0 alcohol was
not used to any measurable extent for alkyl and alk-1-enyl glycerol formation. 相似文献
8.
Suspension cultures of soybean cells incorporated [1-14C] acetate very rapidly into the fatty acid moieties of phospholipids and glycolipids when incubated at 26 C for up to 22
hr. The most rapidly labeled lipid was 3-sn-phosphatidylcholine, which contained 58% of the total fatty acid radioactivity after 16 min; more than 75% of this label
was found to be in the oleic acid of the phosphatidylcholine. After longer periods of incubation, the proportion of14C label decreased exponentially in phosphatidylcholine and increased markedly in an unidentified phospholipid (tentatively,bis-phosphatidic acid), di- and triacylglycerols, and glycolipids. The proportion of radioactivity in oleic acid also decreased
exponentially, accompanied by increases in linoleic acid first and then in linolenic acid. Most of the labeled linolenic acid
at 22 hr was found in the unidentified phospholipid, di- and triacylglycerols, and the glycolipid fraction.
Contribution no. 537, Ottawa Research Station, Agriculture Canada. A preliminary report was presented at the 20th International
Conference on the Biochemistry of Lipids at Aberdeen, Scotland, September 1977. 相似文献
9.
Placental transport of 9-trans [1-14C] octadecenoic (elaidic) and 9-trans,12-trans [1-14C] octadecadienoic (linoelaidic) acids was demonstrated in rats. On the 18th day of gestation, a14C-labeled albumin complex of elaidic or linoelaidic acid was injected into the jugular vein of pregnant rats. For comparison,
9-cis [1-14C] octadecenoic (oleic) or 9-cis,12-cis [1-14C] octadecadienoic (linoleic) acid also was injected into the maternal circulation of rats. All animals were sacrificed 1
hr following injection. Lipid composition and distribution of label were determined in maternal plasma, placental and fetal
tissues. Differences in specific activities of plasma, placental and fetal total lipids indicated a decreasing concentration
gradient for bothcis andtrans isomers of octadecenoic and octadecadienoic acids. Distribution of radioactivity in various lipid components was determined
by thin layer chromatography. Irrespective of the label, the highest percentage of total radioactivity was carried by triglycerides
(TG) in maternal plasma (∼60–80%), and was incorporated mainly in phospholipids (PL) of fetal tissues (∼50–60%). A nearly
equal distribution of the label was found between PL and TG of placental lipids (∼40%). Radioactivity of fatty acid methyl
esters (FAME) determined by radiogas liquid chromatography indicated that after injection of linoelaidate, radioactivity of
maternal plasma, placental and fetal tissue FAME was associated only witht,t-18∶2. Following injection of elaidate, all the radioactivity in placental FAME was associated witht-18∶1; however, in fetal tissues, the label was distributed between 16∶0 andt-18∶1. These findings suggest that, in contrast to linoelaidic acid, rat fetal tissues can metabolize elaidic acid via β oxidation
to form acetyl CoA and palmitic acid. 相似文献
10.
Phospholipids and sterols constituted 70 and 20%, respectively, of the total lipids of the gills of two crabs,Cancer antennarius andPortunus xantusi. Phosphatidylcholine (46–55% of the total phospholipid phosphorous) and phosphatidylethanolamine (24–25%) were the principal
phospholipids present. In both species 1′-alkenyl glycerols were present in about 20% of the phospholipid molecules but were
not detected in the neutral gill lipids. The total ether phospholipids ofC. antennarius gills contained 62% 1-(1′-alkenyl) groups, with the remainder probably being 1-alkyl moieties. Total gill plasmalogen contents
were in the range of 163–184 μmol/g lipid, 82–87% of which was in the phosphatidylethanolamine fraction in both crab species. 相似文献
11.
Differences in the positional incorporation of 9-trans[1-14C] octadecenoic (elaidic) and 9-trans,12-trans[1-14C] octadecadienoic (linoelaidic) acids in fetal lecithin of rats were demonstrated. On the 20th day of gestation, a14C-labeled albumin complex of elaidic or linoelaidic acid was injected into the jugular vein of pregnant rats. For comparative
purposes, 9-cis[1-14C] octadecenoic (oleic) or 9-cis,12-cis[1-14C] octadecadienoic (linoleic acid) was injected into the maternal circulation of rats. Animals were killed 6 hr later. Distribution
of label in total lipids and phospholipids (PL) of fetal tissue was measured by TLC. Irrespective of the label, the highest
percentage of total radioactivity was associated with PL-59 to 67%. Within PL, the major portion of radioactivity was found
in choline phosphoglycerides (CPG)-53 to 67%, and in ethanolamine phosphoglycerides (EPG)-18 to 33%. While linoelaidic acid
was predominantly esterified in the 2-position of CPG, elaidic acid was nearly equally distributed between positions 1 and
2 of lecithin. Distribution of radioactivity within fatty acid methyl esters (FAME) of CPG measured by radio-GLC suggested
that oleic and possibly linoleic acids may be converted to nervonic and arachidonic acid, respectively, in the rat by the
20th day of gestation. Following injection of elaidate, radioactivity of FAME was distributed between palmitate and elaidic
acid indicating that rat fetal tissue may metabolize elaidic acid via β-oxidation. In contrast, following injection of linoelaidate,
radioactivity of FAME was primarily associated withtt-18∶2, suggesting little biotransformation to other fatty acids by fetal tissues. 相似文献
12.
The existence of ether-linked phospholipids, including 1-O-alk-1′-enyl-2-acyl and 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholines and ethanolamines in bonitoEuthynnus pelamis (Linnaeus) white muscle, was investigated by gas chromatography and gas chromatography-mass spectrometry. Chemical ionization
(iso-butane) mass spectrometry of trimethylsilyl ethers derived from the corresponding ether-linked glycerophospholipids proved
effective not only for determining molecular weights but also for structural identification based on the ions [M−R]+, [M−RO]+ and [M+1]+. 1-O-Alk-1′-enyl-2-acyl-sn-glycero-3-phosphocholine and ethanolamine accounted for 3.0–6.0% and 3.6–7.6% of the total glycerophospholipids, respectively.
1-O-Alkyl-2-acyl-sn-glycero-3-phosphocholine and ethanolamine were also determined for one fish and accounted for 1.4% and 0.6% of the total
glycerophospholipids, respectively. The predominant long chains in thesn-1 position of the glycerol moieties were 16∶0, 18∶0 and 18∶1 in the case of the alkenylacyl and alkylacyl components. Fatty
acid distribution of individual glycerophospholipids was also determined. 相似文献
13.
Samuel J. Friedberg 《Lipids》1976,11(8):587-593
Previous studies have shown that ingested fatty alcohols are absorbed as fatty acids and fatty acid esters, particularly triglycerides.
The present study was carried out to determine whether fatty alcohols are also transported as 0-alkyl glyceryl ethers, alk-1-enyl
glyceryl ethers, and as wax esters. Oxidation of fatty alcohols to other lipids was assessed by using a mixture of [1-3H] hexadecanol and [1-14C] hexadecanol of predetermined ratio. The results indicate that the absorption of fatty alcohol, and of its transport forms,
parallels the absorption of labeled fatty acids. Six to 25% of plasma radioactivity was present as 1-0-alkyl diacylglyceryl
ethers with a smaller proportion of ether lipids in the phospholipid fraction. In addition, 4–13% of the ingested hexadecanol
appeared in the plasma as a material having the chromatographic properties of wax ester. Fatty alcohols were not detected
in the plasma as alk-1-enyl lipids. 相似文献
14.
Minimal deviation hepatoma 7288C cells (HTC) were incubated in serum-supplemented and serum-free Swim’s 77 medium in the presence
of D-[1-14C] glucose for 1, 2, 4, 8, 12 and 24 hr. Glucose oxidation to CO2, incorporation into total cell mass, and incorporation into cell and medium lipids were determined. The percentage distribution
of total cell lipid radioactivity in individual neutral and polar lipid classes was followed as a function of time. Degradation
studies of individual lipid classes were performed to ascertain the percentage of radioactivity in acyl and glycerol moieties.
The percentage of D-[1-14C] glucose oxidized to14CO2, incorporated into cell matter and cell lipids was elevated in cells incubated in serum-free medium as opposed to serum-supplemented
medium. The percentage distribution of total cell lipid radioactivity into individual neutral lipid classes from both serum-free
and serum-supplemented cultures was as follows: sterols > triglycerides > free fatty acids > sterol esters. The percentage
distribution of total cell lipid radioactivity into individual polar lipid classes of serum-supplemented cultures was as follows:
phosphatidylcholine > phosphatidylinositol > sphingomyelin > phosphatidylethanolamine > phosphatidylserine. The distribution
of glucose radiolabel into individual polar lipid classes of serum-free HTC cells was different from their serum-supplemented
counterparts: sphingomyelin > phosphatidylcholine > phosphatidylinositol > phosphatidylethanolamine > phosphatidylserine.
Glycerol from glyceride classes contained a higher percentage of radioactivity than the acyl moieties, with this percentage
significantly elevated in serum-free cultures. The data indicate that, although glucose is a substrate for HTC cell lipids,
other precursors present in the culture system also contribute to the lipid constituency of this hepatoma cell line. 相似文献
15.
Radioactively labeled triacylglycerols, 1,3-dioleoyl-2-[1-14C]-palmitoylglycerol and 1,3-[9,10-3H]-dioleoyl-2-palmitoylglycerol, were incubated with dogfish (Squalus acanthias) serum for periods of up to 10.0 hr. Changes in the positional distributions of carbon-14 and tritium within the triacylglycerols in 5.0 hr and 10.0 hr indicate that intermolecular and intramolecular shifts occur among the fatty acids. In addition, a maximum of 8.3% of the carbon-14 and 5.9% of the tritium was incorporated into 1-alkyl-2,3-diacylglycerols; essentially all of this incorporated radioactivity was associated with the acyl chains in the 1.5 and 5.0 hr incubations. In the 10.0 hr incubations, however, 25% of the tritium incorporated into the 1-alkyl-2,3-diacylglycerols was associated with the 0-alkyl chains. Radioactivity was not incorporated significantly into free fatty acids in the 1.5 and 5.0 hr incubations. These results indicate that acyl transfer reactions take place among molecular species of triacylglycerols, as well as between triacylglycerols and 1-alkyl-2,3-diacylglycerols. In the latter case, the conversions appear to be operative in the virtual absence of net biosynthesis. 相似文献
16.
Rac-[1-14C]-palmitylglycerol (chimyl alcohol), rac-[1-14C]-palmityl-2,3-dioleoylglycerol, and rac-palmityl-2,3-[9, 10-3H]-dioleoylglycerol were incubated with dogfish (Squalus acanthias) serum for periods of up to 15.0 hr. The ether bond of the carbon 14 labeled chimyl alcohol was cleaved readily, and radioactivity
was incorporated into free fatty acids and the acyl chains of the major glycerolipids of the serum. In sharp contrast, the
ether bond of the corresponding dioleoyl derivative remained virtually intact. However, the tritium from the acyl chains was
incorporated into glycerolipids via intermolecular rearrangements of fatty acids. The findings are consistent with previous
findings with rat liver microsomes showing that the ether linkages of alkylglycerolipids are resistant to oxidative cleavage
when acyl groups are present on the glycerol moiety. However, substantial differences may exist between the conditions required
for oxidative cleavage of the ether linkage of alkylglycerols in mammals and primative fish.
National Marine Fisheries Service, NOAA, U.S. Department of Commerce. 相似文献
17.
Guinea pig alveolar macrophages were labeled by incubation with either arachidonate or linoleate. Arachidonate labeled phosphatidylcholine
(PC), phosphatidylethanolamine (PE) and triglycerides (TG) equally well, with each lipid containing about 30% of total cellular
radioactivity. In comparison to arachidonate, linoleate was recovered significantly less in PE (7%) and more in TG (47%).
To investigate whether redistributions of acyl chains among lipid classes took place, the macrophages were incubated with
1-acyl-2-[1-14C]arachidonoyl PC or 1-acyl-2-[1-14C]linoleoyl PC. After harvesting, the cells incubated with 1-acyl-2-[1-14C]linoleoyl PC contained 86% of the recovered cellular radioactivity in PC, with only small amounts of label being transferred
to PE and TG (3 and 6%, respectively). More extensive redistributions were observed with arachidonate-labeled PC. In this
case, only 60% of cellular radioactivity was still associated with PC, while 22 and 12%, respectively, had been transferred
to PE and TG. Arachidonate transfer from PC to PE was unaffected by an excess of free arachidonate which inhibited this transfer
to TG for over 90%, indicating that different mechanisms or arachidonoyl CoA pools were involved in the transfer of arachidonate
from PC to PE and TG. Cells prelabeled with 1-acyl-2-[1-14C]arachidonoyl PC released14C-label into the medium upon further incubation. This release was slightly stimulated by zymosan and threefold higher in the
presence of the Ca2+-ionophore A23187. Labeling of macrophages with intact phospholipid molecules appears to be a suitable method for studying acyl chain redistribution
and release reactions. 相似文献
18.
The in vivo incorporation of 1-14C-palmitic acid and 1-0-[8,9-3H] hexadecyl glycerol (chimyl alcohol) by plasmodia of the slime mold,Physarum polycephalum has been studied.14C-palmitate rapidly enters ester and alkyl ether side chains of phospholipids, but alk-1-enyl side chains are labeled more
slowly.3H-chimyl alcohol is incorporated into the alkyl ether phospholipids, which appear to undergo enzymatic desaturation, producing
plasmalogens. The feasibility ofPhysarum as the source of a cell-free enzyme system for plasmalogen synthesis is discussed. 相似文献
19.
Summary Poly[1,1-bis(4-biphenyl)silabutane] (II) has been prepared by the anionic ring opening polymerization of 1,1-bis(4-biphenyl)silacyclobutane. II shows mesomorphic behavior by DSC. The13C NMR T1 relaxation times have been measured. These are found to be smaller than those of poly(1,1-dimethylsilabutane)by an order of magnitude. This may result from interaction of the highly rigid biphenyl side chain moieties. The thermal stability of II is higher than that for other 1,1-disubstituted polysilabutanes. 相似文献
20.
Suspension cultures of cocoa bean tissue readily incorporated exogenous acetate into lipids. The distribution of radioactivity
from acetate in individual lipid classes after 48 hr was 20, 5, 1, 15, 25, and 35% in triglycerides, diglycerides, free fatty
acids, sterol esters, sterols and polar lipids, respectively. The labeled acetate was rapidly incorporated into various fatty
acids within 2 hr. The [1-14C] saturated fatty acids declined slightly after 4 hr, whereas [1-14C] oleate declined significantly after 2 hr. There was a concomitant increase in [1-14C] linoleate. The radioactivity associated with linolenate was relatively high up to 4 hr, declined by 24 hr, and then increased
again. The kinetics of fatty acid labeling suggested that biosynthesis of linolenic acid in cocoa bean suspension culture
may occur via the desaturation of linoleic acid and the chain elongation of dodecatrienoic acid. The patterns of fatty acid
radiolabeling following incubation of cells with [1-14C] laurate was consistent with this mechanism. 相似文献