共查询到20条相似文献,搜索用时 343 毫秒
1.
The acyl and Alk-1-enyl groups of the major phosphoglycerides from ox brain myelin and mouse brain microsomal,mitochondrial and myelin fractions 总被引:1,自引:0,他引:1
The major phosphoglycerides from ox brain myelin and mouse brain microsomal, mitochondrial and myelin fractions were separated
by preparative thin layer chromatography. Alk-1-enyl groups from the alk-1-enyl acyl glycerophosphorylethanolamines were reacted
with 1,3-propanediol to form the 1,3-dioxolane derivatives. Acyl groups were converted to the methyl ester derivatives and
the acyl groups from alk-1-enyl acyl glycerophosphorylethanolamines and diacyl glycerophosphorylethanolamines were also determined
separately. The acyl and alk-1-enyl group compositions of the phosphoglycerides from microsomal and mitochondrial fractions
were quite similar. The ethanolamine and serine phosphoglycerides contained large amounts of 18∶0, 18∶1, 20∶4 and 22∶6 acyl
groups. The choline phosphoglycerides had small amounts of polyunsaturated acyl groups and large amounts of 16∶0, 18∶1 and
18∶0 acyl groups. The mitochondrial cardiolipins contained unusual amounts of several acyl groups including 18∶1, 52%; 18∶2,
6%; and 16.1, 4%. A large portion of the mouse brain 18∶2 is in that fraction. The myelin phosphoglycerides were deficient
in saturated and 22∶6 groups and markedly enriched in 18∶1 and 20∶1 groups when compared with the corresponding microsomal
or mitochondrial phosphoglycerides.
Presented in part at the AOCS Meetings, New York, October 1968 and San Francisco, April 1969. 相似文献
2.
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
3.
The acyl composition of ethanolamine and choline phosphoglycerides from a series of human brain tumors was determined and
compared to that of normal human gray matter. Six glioblastomas, one astrocytoma, one oligodendroglioma, and one meningioma
were analyzed. The total fatty acid composition of ethanolamine phosphoglycerides generally had a higher percentage of 18∶1,
18∶2ω6, and 22∶5ω3 and a lower percentage of 22∶6ω3 than that of normal gray matter. Choline phosphoglycerides from the tumors
also contained a higher than normal percentage of 18∶2ω6. Separate analysis of the acyl groups at the 2 position of the diacyl
and ether-linked components of the phosphoglycerides revealed that the diacyl component of ethanolamine phosphoglyceride from
the tumors had lower than normal amount of 22∶6ω3 and a higher than normal amount of 18∶1 and 18∶2ω6. The acyl composition
of ether-linked ethanolamine phosphoglycerides genearally contained a higher percentage of 20∶4ω6 and a lower percentage of
18∶1 compared to the corresponding fraction from normal gray matter. The astrocytoma analyzed had fatty acid profiles similar
to those of the control with the exception of a greater 18∶2ω6 content. These data demonstrate that the composition of the
acyl moiety at the 2 position of diacyl and ether-linked phosphoglycerides of brain tumors differs from the corresponding
component from normal gray matter and that the ether-linked ethanolamine phosphoglycerides provide an important pool of polyunsaturated
fatty acids from brain tumor phospholipids. 相似文献
4.
An analysis of the phospholipid, cholesterol, and phospholipid fatty acyl composition of isolated plasma membranes of 3T3
and SV3T3 mouse embryo cells has been performed. The results show that the plasma membrane of SV3T3 cells contain relatively
less phosphatidylethanolamine and sphingomyelin and more cholesterol than 3T3 plasma membranes. The fatty acyl composition
of individual phospholipid classes as determined by gas liquid chromatography also showed differences between 3T3 and SV3T3
plasma membranes. The plasma membranes of SV40 transformed 3T3 cells contain: (a) a higher percentage of 18∶1 and less 20∶3
and 20∶4 in phosphatidylethanolamine; (b) a higher percentage of 18∶1 in phosphatidylserine; and (c) a higher percentage of
18∶2 and 20∶4 in phosphatidylinositol. 相似文献
5.
Phospholipid classes were separated from mouse brain lipid extracts by preparative thin-layer chromatography (TLC). Methyl
esters were prepared from the intact phospholipids by direct transesterification at room temperature in the presence of silica
gel by using 0.5m NaOH-methanol in order to prevent interference by aldehydes or derivatives. Dimethyl acetal derivatives of phosphoglyceride
alkenyl ethers (alkenyl moiety with a double bond in 1,2-position relative to oxygen linkage) were prepared, using 5% concentrated
HCl in methanol, followed by preparative TLC for isolation.
The major phospholipids present were ethanolamine phosphoglycerides (EPG) 39.8%, choline phosphoglycerides (CPG) 39.7%, serine
phosphoglycerides (SPG) 15.0%, and sphingomyelin (Sph) 5.4%. One-fifth of the total phospholipids (PL) were in the form of
plasmalogens, mainly EPG. Choline and serine plasmalogens were present in trace quantities. The major aldehyde components
of the plasmalogens were 16∶0, 18∶0, and 18∶1.
The EPG were rich in long-chain poly-unsaturated fatty acids, including 28.8% of 22∶6 and 17.0% of 20∶4, but contained only
7.2% of 16∶0. In contrast, the CPG contained 39.6% of 16∶0, and 31.0% of 18∶1 with a small content of polyunsaturated fatty
acids. The SPG exhibited a still different pattern containing 38.2% of 18∶0, 23.2% of 18∶1, 24.3% of 22∶6, 2.9% of 16∶0, and
3.8% of 20∶4.
Presented in part at the AOCS Meeting, New Orleans, May 1967. 相似文献
6.
The distribution of phospholipids as well as their fatty acid compositions of rat mammary tissues were examined during pregnant,
lactating, and post-weaning periods. There was no apparent change in phospholipids and their acyl groups during the early
and late pregnant periods. However, tissue phospholipid composition was different during pregnant, early, and late lactating
periods. After parturition, there was a marked increase in the proportion of diacyl-glycerophosphorylcholine in the phospholipids
of mammary tissue, but this proportion decreased gradually during lactation. The decrease in diacyl-glycerophosphorylcholine
during lactation was marked by a corresponding increase in diacyl-glycerophosphorylethanolamine. Although the shorter chain
fatty acids of triglycerides were increased during lactation, only a small proportion of these fatty acids was found in the
phosphoglycerides. Marked changes in acyl group composition of individual phospholipids are found during these different physiological
stages. In general, there was a rapid decrease in 20∶4 and an increase in 18∶2 in the major phosphoglycerides during parturition.
The proportion of 20∶4 in the phosphoglycerides remained low throughout the entire lactating period, while that of 18∶2 continued
to increase 2–3 fold. Most of the changes in acyl group of the phosphoglycerides during lactation returned to normal ca. 10
days after weaning. A possible relationship of the variation of phospholipid and acyl group compositions in mammary tissue
to changes in hormonal pattern during different physiological stages is discussed. 相似文献
7.
The content and composition of neutral lipids and phosphoglycerides from full-grown prophase-arrestedBufo arenarum Hensel oocytes and from their ghost preparations were studied. The ghosts obtained are highly enriched in plasma membrane
as suggested by the activity of 5′-nucleotidase, a marker enzyme, and the level of typical membrane components such as sphingomyelin,
phosphatidylserine (PS), phosphatidylinositol (PI), and phosphatidic acid. In whole oocytes, triacylglyceride (TAG) comprises
about 60% of the total lipids followed by phosphatidylcholine (PC), cholesterol, and phosphatidylethanolamine (PE). TAG and
diacylglycerides have a similar unsaturation index. PC and PE account for about 80% of the phosphoglycerides in the whole
oocyte and in their plasma membrane-enriched fractions. Arachidonic acid (20∶4n−6), 18∶0, and 16∶0 make up about 80 mol% of
the total fatty acids in Pl in whole oocytes and ghost fractions. The unsaturation index in PS is higher in intact oocytes
than in ghost preparations, probably owing to the significant amount of 20∶4n−6 which comprises 23 mol% of the total fatty
acids in whole oocytes. The fatty acid profile in phosphatidic acid from whole oocytes is rather different from that in ghosts.
Sphingomyelin contains mainly saturated and monounsaturated fatty acids, 24∶1 being the principal very long chain unsaturated
fatty acid in both oocytes and ghosts. 相似文献
8.
In this study, the 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine content of human platelets was determined. The distribution of arachidonate among the 1,2-diacyl,
1-O-alkyl-2-acyl, and 1-O-alk-l′-enyl-2-acyl classes of choline- and ethanolamine-containing phosphoglycerides was also assessed. The major platelet
phospholipids were choline-containing phosphoglycerides (38%), ethanolamine-containing phosphoglycerides (25%) and sphingomyelin
(18%), with smaller amounts of phosphatidylserine (11%) and phosphatidylinositol (4%). In addition to the diacyl class, the
choline-linked fraction was found to contain both 1-O-alkyl-2-acyl (10%) and 1-O-alk-l′-enyl-2-acyl (9%) species. The ethanolamine-linked fraction, on the other hand, had an elevated level of the 1-O-alk-l′-enyl-2-acyl (60%) species and a small amount of the 1-O-alkyl-2-acyl component (4%). The major fatty acyl residues found in all classes of the choline and ethanolamine phospholipids
were 16∶0, 18∶0, (Δ9), 18∶2(n−6) and 20∶4(n−6). The 1-O-alk-l and 1-O-alk-l′-enyl fraction of the ethanolamine-linked phospholipids also contained substantial amounts of 22∶4(n−6), 22∶5(n−3)
and 22∶6(n−3) acyl chains. Arachidonate comprised 44% of the acyl residues in thesn-2 position of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine. Corresponding values for the diacyl and 1-O-alk-l′-enyl-2-acyl species were 23% and 25%, respectively, based on all 20∶4(n−6) being linked to thesn-2 position of all classes. In the ethanolamine-linked phosphoglycerides, arachidonate constituted 60%, 20% and 68% of the
acyl groups in thesn-2 position of the 1,2-diacyl, 1-O-alkyl-2-acyl and 1-O-alk-l′-enyl-2-acyl classes, respectively. The content of 1-O-alkyl-2-acyl-sn-glycero-3-phosphocholine appears sufficient to support the synthesis of platelet activating factor by a deacylation-reacylation
pathway in platelets. Our findings also demonstrate that human platelets contain a significant amount of 1-O-alkyl-2-arachidonyl-sn-glycero-3-phosphocholine that could possibly serve as a precursor of both platelet activating factor and bioactive arachidonate
metabolites. 相似文献
9.
Analysis of phospholipids in porcine, bovine and rat adipose tissue revealed a relatively high level of plasmalogens (O-alk-1-enyl lipids). About 50% of the ethanolamine phospholipids in the pig and beef samples consisted of alk-1-enylacylglycerophosphorylethanolamine,
and the corresponding value for the rat sample was near 35%. In the ethanolamine and choline phospholipid fractions, theO-alk-1-enyl moieties were almost exclusively 16∶0, 18∶0 and 18∶1, whereas the acyl moieties had chain lengths ranging from
16 to 22 carbon atoms with a high degree of unsaturation. 相似文献
10.
Male guinea pigs fed a vitamin C-deficient diet for 3 weeks had lower concentrations of cholesteryl esters in their adrenals
than did control animals fed the recommended intake of the vitamin. Not all esters were affected to the same degree, and the
fatty acid profiles of the esters from control and deficient guinea pigs differed; there was proportionately more palmitic
and linoleic acids and less docosatetraenoic acid [22∶4 (n−6)] in the deficient guinea pig adrenal esters. [Fatty acids are
designated as X∶Y (n−Z), where X and Y are the numbers of carbon atoms and olefinic bonds in the acid and Z is the number
of carbon atoms after the terminal olefinic bond.] A 100-fold excess of vitamin C in the diet also resulted in lower concentrations
of adrenal cholesteryl esters than did the control diet, but they were not as low as in the deficient animals. Fatty acid
profiles were similar for esters from control and excessively supplemented guinea pigs. Vitamin C deficiency apparently imposes
a long term stress which results in a depletion of adrenal cholesteryl esters, possibly specific esters, to meet the requirements
for glucocorticoid synthesis. 相似文献
11.
Cell-free homogenates of lactating mammary gland of gerbils maintained on a diet of sunflower seed, guinea pig chow and oats
(Diet 1) or a diet of guinea pig chow and oats (Diet 2) and of rats maintained on laboratory chow (Diet 3) were incubated
with14C-labeled acetate, acetyl CoA or malonyl CoA aerobically. A large proportion of the14C from14C-acetate and14C-acetyl CoA incorporated into fatty acids by homogenates from gerbils on Diet 1 was in unsaturated compounds, particularly
in 18-carbon and 20-carbon dienoic acids, compared to preparations from animals on Diets 2 or 3. The two radioactive dienoic
acids were proven to be Δ9,12 18∶2 and Δ11,14 20∶2, and the latter was shown to be a direct elongation product of Δ9,12 18∶2 by the substrate14C-acetyl CoA. In all experiments14C from14C-malonyl CoA was incorporated predominantly into 14∶0 and 16∶0, and very little incorporation occurred into unsaturated fatty
acids in homogenates made either from gerbil or rat. Total fatty acids isolated from homogenates and from milk fat (fat floating
on the centrifuged homogenates) of gerbils on Diet 1 had a higher proportion of 18∶2 than animals on the other two diets,
a reflection of the large dietary intake of linoleic acid by gerbils on Diet 1. Under these conditions the amount of 18∶2
in the mammary gland had a significant effect on the products of the incubation. 相似文献
12.
The fatty acid composition of individual phospholipids in subcellular fractions of sheep platelets and the asymmetrical distribution
of phosphatidylethanolamine (PE) fatty acyl chains across the plasma membrane were examined. The main fatty acids of total
lipid extracts were oleic (18∶1; 32–41%), linoleic (18∶2, 10–17%), stearic (18∶0; 13–15%), palmitic (16∶0; 11–15%) and arachidonic
(20∶4; 8–12%) acids, with a saturated/unsaturated ratio of about 0.4. Each phospholipid class had a distinct fatty acid pattern.
Sphingomyelin (SM) showed the highest degree of saturation (50%), with large proportions of behenic (22∶0), 18∶0 and 16∶0
acids. The main fatty acid in PE, phosphatidylserine (PS) and phosphatidylcholine (PC) was 18∶1n−9. Our findings suggest that
fatty acids are asymmetrically distributed between thecholineversus the non-choline phospholipids, and also between plasma membranes and intracellular membranes. The transbilayer distribution
of PE fatty acids in plasma membranes from non-stimulated sheep platelets was investigated using trinitrobenzenesulfonic acid
(TNBS). A significant degree of asymmetry was found, which is a new observation in a non-polar cell. The PE molecules from
the inner monolayer contained higher amounts of 18∶2 and significantly less 18∶1 and 20∶5 than those found in the outer monolayer,
although no major differences were detected in the transbilayer distribution of total unsaturatedversus saturated PE acyl chains. 相似文献
13.
Plasma phospholipids in several common mammalian species, including cat, cow, dog, goat, guinea pig, horse, pig, rabbit, rat,
and sheep, were analyzed by using chromatographic and spectrophotometric methods. Lipids were extracted from plasma with chloroform-methanol
2∶1 (v/v) and freed of nonlipid material by passage through a Sephadex column. The phospholipids were separated by two-dimensional
thin-layer chromatography (TLC). Spots were identified by spray reagents, also by infrared spectrophotometry. The relative
distribution of the phospholipids was determined by phosphorus analysis on the spot scraped off the TLC plate.
Lecithin, lysolecithin, and sphingomyelin were found in the plasma of all species and accounted for more than 95% of the phospholipids
except in the rodents. Lecithin was without exception the major phospholipid in plasma (56 to 83%). Lysolecithin and sphingomyelin
content varied between 8 and 23% and 6 and 15% respectively. Phosphatidyl ethanolamine and phosphatidyl inositol were the
only noncholine-containing phospholipids detected (detection limits 0.2%) in the plasma of these species. Together these compounds
usually made up less than 5% of the total phospholipid. Rodents were an exception, especially the guinea pig, which had 21.7%
phosphatidyl ethanolamine. 相似文献
14.
The lipid composition of plasma membranes isolated from differentialted and undifferentiated L6 myoblasts has been compared. In general, the plasma membranes of differentiated L6 myoblasts have a higher cholesterol to phospholipid molar ratio than plasma membranes of undifferentiated cells. Differentiated
L6 myoblasts have increased relative amounts of phosphatidylethanolamine and phosphatidylcholine in their plasma membrane and
a decreased relative amount of sphingomyelin when compared with the plasma membranes of undifferentiated myoblasts. In addition,
preliminary results show that differentiated L6 myoblasts plasma membrane phospholipid shows differences in the fatty acyl composition, specifically there appears to be
relatively more 17∶0 and 24∶1 and less 16∶1 and 18∶1 than in plasma membrane phospholipids of undifferentiated L6 myoblasts. These observations indicate that significant changes in plasma membrane lipid composition occur during myoblast
differentiation. The role that changes in lipid composition play in control of cellular differentiation, however, remains
to be elucidated. 相似文献
15.
The long chain bases of sphingomyelin from Morris hepatoma 7777 and host and control livers were analyzed by capillary gas
liquid chromatography. Sphingosine (18∶1) was the major long chain base of control livers (66.5%) and hepatomas (65.6%), but
hepatomas also had a high percentage (9.3 vs 4.4) of the 16∶1 homolog. Host liver had the most unusual long chain base composition,
with ca. equal 16∶1 (24.4%) and 18∶1 (21.4%) and high amounts of 20-carbon bases (9.2% 20∶0 and 15.3% 20∶1). These differences
may be related to the aberrant fatty acid metabolism known to occur in tumor-bearing animals. Such large perturbations in
the long chain base composition of hepatic sphingomyelin are unprecedented and could have a major impact on the properties
of host membranes. 相似文献
16.
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. 相似文献
17.
Lipids from bovine optic nerve were analyzed. The total content of 16.5% by weight included 27.2% nonpolar lipids, 26.1% glycolipids,
and 46.7% phospholipids by weight. Free cholesterol was the major component of the nonpolar lipid fraction. The cerebrosides,
73.5% of total glycolipids, were separated by thin layer chromatography (TLC) into two bands (upper and lower) that were present
in equal proportion. Cerebroside sulfates comprised about 27.5% of total glycolipids. Gangliosides were also detected in the
glycolipid fraction. In order of predominance, choline glycerophospholipids, ethanolamine glycerophospholipids, ethanolamine
plasmalogens, serine glycerophospholipids, sphingomyelins, and inositol glycerophospholipids were the major phospholipids.
Palmitoyl (16∶0), stearoyl (18∶0), and oleoyl (18∶1) groups were the major acyl groups in all neutral and phospholipid classes.
However, ethanolamine glycerophospholipids, serine glycerophospholipids, and inositol glycerophospholipids contained a large
percentage of 22∶6 (docosahexaenoyl) group. The major alk-1-enyl groups of the plasmalogens were 16∶0, 18∶0, and 18∶1. Steroyl
(18∶0), lignoceroyl (24∶0), and nervonoyl (24∶1) were the major acyl groups in all sphingolipids. Lower cerebroside band and
cerebroside sulfates contained large amount of hydroxylignoceroyl (cerebronoyl) and hydroxynervonoyl groups.
This investigation was supported by Grants DE-03191 and 2S06-RR-08037 from the National Institutes of Health, Bethesda, MD. 相似文献
18.
The lipophilic components of choline phosphoglycerides and ethanolamine phosphoglycerides obtained from the salt gland of
herring gull and eider duck and from the rectal gland of spiny dogfish were investigated by means of thin-layer chromatography,
gas chromatography, and gas chromatography-mass spectrometry. All phospholipids analyzed were shown to contain small amounts
of plasmalogens, and mainly C16, C18, and C18∶1 aldehyde was detected. The fatty acids were composed of saturated, unsaturated,
straight chain, and branched chain types, ranging between 14–22 carbon atoms. The lipophilic composition of the rectal gland
phospholipids showed a higher degree of unsaturation and the presence of more branched chain fatty acids than that of the
birds, possibly related to body temperature. 相似文献
19.
Adequate accumulation of polyunsaturated essential fatty acids, in particular docosahexaenoic acid (22∶6n−3), into membrane
phospholipids is critical for optimal fetal brain development. This process is maximal during the period of rapid neurite
outgrowth, neuritogenesis, which precedes the major growth phase, myelination. There is no information about differential
changes during gestation to individual brain phospholipid molecular species which contain 22∶6n−3. Such details of brain development
would be concealed by total fatty acid analysis of isolated phospholipid classes. We have detailed phosphatidylcholine (PC)
and phosphatidylethanolamine (PE) molecular species compositions in developing fetal guinea pig brain. Total brain PC concentration
increased substantially between 40 and 68 (term) d of gestation, corresponding to myelination, while PE increased in a biphasic
manner between 25–35 d, which was coincident with onset of neuritogenesis, and 40–68 d. Fetal brain development was accompanied
by complex changes in the concentration of individual phospholipid molecular species. During early gestation (25–40 d) 22∶6n−3
was enriched in both PC and PEsn−1 16∶0 molecular species. However, between 40 d and term there was no further increase in brain PC 22∶6n−3 content, while
brain PE was significantly enriched in both PE 18∶1/22∶6 and PE18∶0/22∶6. We hypothesize that accumulation of 22∶6n−3 intosn−1 18∶1 and 18∶0 species represents establishment of a 22∶6n−3-containing membrane PE pool which may be turned over more slowly
thansn−1 16∶0 species. Identification of specific changes in membrane phospholipids which are associated with defined events in
brain development may provide a basis for assigning functional roles to individual molecular species. 相似文献
20.
Feeding an oil from Lunaria biennis rich in 22∶1n−9 and 24∶1n−9 to homozygous quaking (qk.qk) mice caused a large increase in the percentage of 24∶1n−9 and corresponding
decreases in the percentage of 24∶0 and 22∶0 in sphingomyelins from liver, erythrocytes, and milk. Brain sphingomyelin from
2-wk-old qk.qk pups born to qk.qk mothers maintained on the Lunaria oil had essentially normal percentage of 24∶1n−9 and 18∶0, in contrast to pups born to mothers maintained on a control oil
rich in 18∶1n−9 whose brain sphingomyelin had a markedly reduced percentage of 24∶1n−9 and an increased percentage of 18∶0.
After 2 wk and up to and beyond weaning, the qk.qk pups from Lunaria-fed mothers weaned on to the Lunaria diet had a markedly decreased percentage of 24∶1n−9 in their brain sphingomyelin, accompanied by an increased percentage
of 18∶0, as compared to heterozygous quaking mice. However, the percentage of 24∶1n−9 in brain sphingomyelin in qk.qk pups
weaned on to the Lunaria diet continued throughout this period (2–8 wk postbirth) to be significantly higher than in qk.qk pups weaned on to the control
diet. We conclude that dietary 24∶1n−9 influences the fatty acid composition of brain sphingomyelin in qk.qk mice, but only
via the mother in pre- or early postnatal animals. We further consider that the dietary effects may be elicited mainly in the
sphingomyelin of nonmyelinated brain cells, and that the nervonic acid in myelin sphingomyelin may be formed mainly by chain
elongation in oligodendrocytes from shorter chain fatty acid precursors. 相似文献