共查询到20条相似文献,搜索用时 15 毫秒
1.
Developmental changes of the lipidic part of the neutral glycosphingolipids of the rat stomach 总被引:2,自引:0,他引:2
Neutral glycolipids were purified from the glandular part of the stomach of rats of different ages from 20 days of gestation to 60 days after birth. The two major glycolipids were identified as glucosylceramide and isogloboside. Free ceramide was also detected. The concentrations of these sphingolipids remained almost stable with development. Monohexosylceramide contained 55 and 68% of 2-hydroxylated fatty acids at 20 and 22 days of gestation, respectively, and 82% in the adult. Its three major bases, C18-sphingenine, C18- and C20-4D-hydroxysphinganine were characterized by gas-liquid chromatography and mass spectrometry of their N-acetyl-O-trimethylsilyl derivatives. The occurrence of the bases changed with development. C18-sphingenine contributed for 26% of the bases at birth and 65% in the adult. Conversely, C18-4D-hydroxysphinganine contributed for 35% of the bases at birth and 9% in the adult. The ceramide part of isogloboside consisted of nonhydroxylated fatty acids and mainly C18-sphingenine throughout development. The percentage of long-chain fatty acids was higher in older animals. These results stressed the specificity of the lipidic part of the rat gastric glycolipids and their specific evolution during the development. 相似文献
2.
Neutral glycosphingolipids were isolated from the colon of rats between birth and adulthood. The glycolipid concentration was stable during this period. Epithelial cells of the adult colon contained three times more glycolipids than the whole organ. The distribution pattern underwent only minor modifications during development. Free ceramide contributed for 23-27% of the total neutral sphingolipids at all ages. In 6-day-old rats, it was constituted of nonhydroxylated fatty acids linked to C18-sphingenine (57.3% of the bases), C18- and C20-4D-hydroxysphinganine (24.2 and 14.0% of the bases, respectively). This composition was essentially maintained during development. Glucosylceramide was the major glycolipid at all ages (40-50% of the total neutral sphingolipid content). At birth, 40% of its fatty acids were 2-hydroxylated and 93% of the bases were C18-4D-hydroxysphinganine. In adult epithelial cells, 75% of the fatty acids were 2-hydroxylated and C18- and C20-4D-hydroxysphinganine contributed for 66 and 25% of the bases, respectively. A transient increase of the contribution of nonhydroxylated fatty acids and C18-sphingenine was observed during the first week of life. C20-4D-hydroxysphinganine, which was characterized by gas-liquid chromatography of its aldehydes after periodate oxidation and of its N-acetyl O-trimethylsilyl derivatives, appeared after birth and reached 20% of the bases after two weeks. These findings are another example of the specificity of the lipidic part of glucosylceramide during the ontogenic differentiation. 相似文献
3.
M E Breimer 《Journal of lipid research》1975,16(3):189-194
Sphingomyelins were isolated from mucosal layers of bovine rennet stomach, duodenum, jejunoileum, and colon ascendens. The ceramides obtained after phospholipase degradation were characterized by thin-layer chromatography, mass spectrometry, and gas-liquid chromatography. The main ceramide group from all regions consisted of dihydroxy long-chain bases and normal fatty acids. Sphingosine was the predominant base in all these fractions, and only in rennet stomach were smaller amounts of the C17 and C20 homologs present. Normal saturated C16, C18, C22, and C24 fatty acids were most abundant. In rennet stomach there was in addition a ceramide group having dihydroxy long-chain bases in combination with hydroxy fatty acids. Sphingosine was the predominant long-chain base and the fatty acids were 2-hydroxy C16, C22, C23, and C24. From jejunoileum three minor ceramide fractions were isolated; these consisted of phytosphingosine and normal fatty acids C22-C24), sphingosine and 2-hydroxy fatty acids (C16-C24), and phytosphingosine and 2-hydroxy fatty acids (C22-C24), respectively. No branched paraffin chains were found in significant amounts. Sphingomyelins with trihydroxy long-chain bases and 2-hydroxy fatty acids found in jejunoileum were also detected in bovine kidney and have not been demonstrated before. These sphingomyelins from both kidney and jejunoileum showed a preferential combination of trihydroxy bases and fatty acids with very long chains (C22-C24). 相似文献
4.
A series of fluorescent N-acylsphingosines: synthesis, physical properties, and studies in cultured cells 总被引:15,自引:0,他引:15
We have previously shown that when cultured fibroblasts are briefly incubated at 2 degrees C with a fluorescent (NBD) analogue of ceramide, N-[N-(7-nitro-2,1,3-benzoxadiazol-4-yl)-epsilon-aminohexanoyl]-D-e rythro- sphingosine, fluorescent labeling of the mitochondria, endoplasmic reticulum, and nuclear envelope occurs. During further incubation at 37 degrees C, the Golgi apparatus and later the plasma membrane become intensely fluorescent. Concomitantly, the fluorescent ceramide is metabolized to fluorescent analogues of sphingomyelin and glucosylceramide [Lipsky, N. G., & Pagano, R. E. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 2608-2612]. In the present study we synthesized fluorescent N-acylsphingosine analogues using various long-chain bases (D-erythro-sphingosine, L-erythro-sphingosine, D-threo-sphingosine, L-threo-sphingosine, D-erythro-dihydrosphingosine, L-threo-dihydrosphingosine, phytosphingosine, and 3-ketosphingosine) and fluorescent fatty acids (epsilon-NBD-aminohexanoic acid; D- or L-alpha-OH-epsilon-NBD-aminohexanoic acid; D- or L-alpha-NBD-aminohexanoic acid). Using previously described resonance energy transfer assays, we examined the rates of spontaneous transfer of these compounds between liposomes and their ability to undergo transbilayer movement. The fluorescent N-acylsphingosine analogues had half-times for spontaneous transfer of 0.3-4.0 min at 25 degrees C, and all were capable of transbilayer movement in lipid vesicles. The metabolism and intracellular distribution of analogues in cultured fibroblasts were also studied. While most of the fluorescent N-acylsphingosines were significantly metabolized to the corresponding sphingomyelin analogues, metabolism to glucosylceramide was strongly dependent on the long-chain base and the stereochemistry of the fluorescent fatty acid moiety.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
The neutral sphingolipids from chicken erythrocytes were characterized. The total concentration of neutral sphingolipids was found to be 480 nmol/g of dry stroma. They were isolated and purified by droplet counter-current chromatography, Iatrobeads column chromatography, and preparative thin-layer chromatography. The major neutral sphingolipids were free ceramide, ceramide monohexoside, ceramide dihexoside, and ceramide pentahexoside, which represented 43%, 23.5%, 10.0%, and 3.6% of the long chain bases, respectively. Thus, free ceramide was the most abundant neutral sphingolipid in chicken erythrocytes. Ceramide monohexoside was composed of more galactosylceramide than glucosylceramide. Galabiosylceramide was found in the ceramide dihexoside fraction together with lactosylceramide. Ceramide pentahexoside was a Forssman glycolipid. There were two groups of neutral sphingolipids; one had mainly C16 fatty acid and the other had C22 and C24 fatty acids. In both groups sphingosine (d18:1) was predominant as a long chain base. 2-Hydroxy-C16 fatty acid was a major component of one of the ceramide monohexosides. 相似文献
6.
Sphingolipids in bean leaves (Phaseolus vulgaris) 总被引:1,自引:0,他引:1
Phytoglycolipid has been isolated for the first time from plant leaves (Phaseolus vulgaris). The purified product (almost identical with the phytoglycolipid isolated from flax seed) was a ceramide attached through phosphate diester linkage to an oligosaccharide, which consisted of the usual trisaccharide unit (inositol, hexuronic acid, hexosamine) to which were attached mannose, galactose, and arabinose. The major fatty acids were the saturated 2-hydroxy C(22), C(24), and C(26) acids; the major long-chain bases were dehydrophytosphingosine (d-ribo-1,3,4-trihydroxy-2-amino-8-trans-octadecene) (53%) and phytosphingosine (d-ribo-1,3,4-trihydroxy-2-amino-octadecane) (32%). A ceramide and a cerebroside were also isolated. In the ceramide the major fatty acids and the major long-chain bases were the same as in the phytoglycolipid. In the cerebroside, the fatty acid composition was similar to that in the ceramide and phytoglycolipid, but the long-chain bases consisted of dehydrophytosphingosine and phytosphingosine (7:1) with a substantial amount of unidentified long-chain base. The sugar component was glucose. 相似文献
7.
Sphingomyelin from the guinea pig Harderian gland was isolated and characterized. The purified sphingomyelin gave a broad spot on thin-layer chromatography. The fatty acid composition of the whole sphingomyelin was 71% nonhydroxy acids and 29% 2-hydroxy acids. Methyl-branched fatty acids were only 2% of the total acids. The long-chain bases were composed of straight-chain sphingenines (50%) and sphinganines (6%). Methyl-branched long-chain bases were 44% of the bases. The sphingomyelin was further separated into four fractions (I, II, III, IV) by high-performance liquid chromatography. The ratio of fractions I, II, III, and IV was approximately 2:5:2:1, respectively. The fatty acids of fractions I and II consisted of nonhydroxy acids and those of fractions III and IV were 2-hydroxy acids. The long-chain bases of fractions I and III were sphinganines including 10-, 9-, and 8-methylsphinganines and anteiso-sphinganines. These methyl-branched bases occupied about 70% of the total sphinganines. The long-chain bases of fractions II and IV consisted of sphingenines. The methyl-branched unsaturated bases were only 30% of the total sphingenines, all in the anteiso-form. Thus, the sphingomyelin obtained from guinea pig Harderian gland had complex compositions of fatty acids and long-chain bases, and half the number of long-chain bases had methyl branches. The methyl-branched fatty acids were only a minor component. These characteristics are similar to those of cerebrosides isolated from the same source. 相似文献
8.
1. Two sphingophosphonolipids were isolated from the lipids of the ciliated protozoan, Tetrahymena pyriformis WH-14. They were ceramide N-methyl-2-aminoethylphosphonate (CMAEP) and ceramide 2-aminoethylphosphonate (CAEP), in yields of 0.05 mg/g and 1.74 mg/g dry cells, respectively. 2. Two chromatographically distinguishable CAEP species were found, a slow-moving major component and a minor component which moved faster; the slow-moving one contained primarily hydroxy fatty acids, while in the other one nonhydroxy fatty acids were predominant. However, their long-chain base constituents were similar. 3. The major fatty acids of CAEP were 2-hydroxy acids with carbon numbers of 16 to 19, which were almost exclusively iso-types. The fatty acids of CMAEP consisted mainly of palmitic, iso-octadecanoic, and 2-hydroxy iso-heptadecanoic acids. 4. The long-chain bases were dominated by C16, C17, and C19 iso-4-sphingenine homologs. 相似文献
9.
Candida lipolytica yeast was grown batchwise on two different carbon sources, glucose and n-hexadecane. Free ceramides were quantitatively isolated from sphingolipid fractions of total lipids by a combination of column
chromatography and preparative thin-layer chromatography. Their composition, after acid methanolysis, was analysed by gas-liquid
chromatography. The ceramide content accounted for 2.6% of the total cell lipids in hexadecane-grown cells, which was 1.5
times higher than in glucose-grown cells. The fatty acid composition of ceramides was characterized by the predominance of
fatty acids shorter than 20 carbon atoms and by high concentrations of fatty acids with 16 carbon atoms after growth on both
carbon sources. The dominant fatty acid was hydroxylated 16:0 in the glucose-grown cells and 16:0 in the hexadecane-grown
cells. The striking finding was the low degree of fatty acid hydroxylation and relatively high proportion of odd-numbered
fatty acids in ceramide of the n-hexadecane-grown cells. The ceramides contained an unusual long-chain base composition. In hexadecane-grown cells more than
60% of the long-chain bases were C19 phytosphingosine. In glucose-grown cells more than one-half of the total long-chain bases were tetrahydroxy bases, 4,5-dihydroxysphinganine
and 4,5-dihydroxyeicosasphinganine.
Received: 20 April 1998 / Received revision: 10 July 1998 / Accepted: 29 July 1998 相似文献
10.
Glycolipids were purified from the total lipid extract of the testis or milt of a kind of puffer (Fugu rubripes rubripes) by adsorption column chromatography using silicic acid and magnesium silicate and by preparative silica gel TLC. The glycolipids were identified as glucosylceramide (116 mug/g wet tissue) and galactosylceramide 26.7 mug/g). Seminolipid, a sulfagalactolipid specific to mammalian testis was not detected, but the presence of a small amount of sulfatide (15.2 mug/g) was demonstrated. The long-chain bases of both cerebrosides were mainly C18-sphingenine, but in sulfatide, C20-sphingenine was more abundant than C18-sphingenine. In both cerebrosides and sulfatide, the fatty acid compositions were similar, with nervonic acid as the predominant component. Two species of gangliosides were also obtained and were identified as N-acetylgalactosaminyl(1 leads to 4)[N-acetylneuraminyl(2 leads to 3)]galactosyl(1leads to 4)glucosylceramide (59.8 mug/g) and N-acetylneuraminyl(2 leads to 3)galactosyl(1 leads to 4)N-acetylglucosaminyl(1 leads to 3)galactosyl(1 leads to 4)glucosylceramide (45.0 mug/g). The long-chain bases of the two gangliosides consisted of C18-spingenine and C20-sphingenine, and the major fatty acids were palmitic and stearic acids. 相似文献
11.
Watanabe M Miyagi A Nagano M Kawai-Yamada M Imai H 《Bioscience, biotechnology, and biochemistry》2011,75(5):877-881
Rumex obtusifolius L., a member of Polygonaceae, is one of the world's worst weeds. We characterized the glucosylceramide molecular species in leaves of R. obtusifolius by liquid chromatography/tandem mass spectrometry. 4,8-Sphingadienines were principally paired with 2-hydroxy palmitic acids. In contrast, 4-hydroxy-8-sphingenines were chiefly attached to 2-hydroxy fatty acids with 22 to 26 carbon-chain length. A unique characteristic of the 2-hydroxy fatty acid composition of R. obtusifolius was the high content of n-9 monoenoic 2-hydroxy fatty acids with 22 and 24 carbon-chain length. The levels of the Z and E stereoisomers of the 8-unsaturated long-chain bases were reliably distinguished from those in other plant families in ten species of Polygonaceae. 相似文献
12.
J Ko?cielak W Ma?liński J Zieleński E Zdebska T Brudzyński H Miller-Podraza B Cedergren 《Biochimica et biophysica acta》1978,530(3):385-393
Major neutral glycosphingolipids were isolated from human plasma and their structures and fatty acid compositions studied. The four neutral glycosphingolipids of plasma were characterized as Glc beta(1 leads to 1)ceramide, Gal beta(1 leads to 1)- ceramide, Gal beta(1 leads to 4) Glc beta (1 leads to 1)ceramide, Gal alpha(1 leads to 4) Gal beta(1 leads to 4) Glc beta(1 leads to 1)ceramide and GalNAc beta(1 leads to 3) Gal (1 leads to 4) Gal (1 leads to 4) Glc beta(1 leads to 1)-ceramide. The glycosphingolipids contained mostly short chain fatty acids of which most prominent was C16. Erythrocyte glucosylceramide and lactosylceramide exhibited similar fatty acid compositions as their plasma counterparts. Triglycosylceramide and globoside of erythrocytes contained almost exclusively long-chain fatty acids. In lactosylceramide obtained from "p" erythrocytes, an accumulation of long-chain fatty acids was found; this accumulation was not observed, however, in lactosylceramide isolated from "p" plasma. It was concluded that plasma and erythrocyte glycosphingolipids are synthesized at separate sites where short- and long-chain fatty acids, respectively, are available. Plasma and erythrocyte glucosylceramide, and probably a fraction of lactosylceramide, exchange between plasma and erythrocyte pools. The latter conclusion is discussed in the light of the relative roles of carbohydrate and lipid moieties of the glycosphingolipids in maintaining their association with erythrocyte membranes. 相似文献
13.
A novel fucose-containing neutral glycosphingolipid (GL-5) was purified from the eggs of the sea urchin, Hemicentrotus pulcherrimus. The chemical structure was determined to be Fuc alpha 1-3GalNAc beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-4Glc beta 1-1Cer by methylation analysis, partial acid hydrolysis, fast atom bombardment mass spectrometry, and proton nuclear magnetic resonance spectroscopy. The unique characteristics of GL-5 are that: the reducing terminal disaccharide portion is not Gal beta 1-4Glc but GlcNAc beta 1-4Glc; it includes a GalNAc beta 1-4GlcNAc sequence and a Fuc-GalNAc linkage; the defucosylated core is a novel trisaccharide chain; and the sugar structure is one of the smallest ever characterized for a difucosylated glycolipid. The major fatty acids were 22:1 and 22h:1, and about 30% of the total acids was 2-hydroxylated. All the long-chain bases were phytosphingosines, of which about 90% was n-t18:0. The similarity of the ceramide moiety to that of glucosylceramide from the same eggs [Kubo, H. et al. (1992) J. Biochem. 111, 726-731] suggests a close biosynthetic relationship between GL-5 and the glucosylceramide. 相似文献
14.
Isolation of a novel sphingoglycolipid containing glucuronic acid and 2-hydroxy fatty acid from Flavobacterium devorans ATCC 10829 总被引:2,自引:0,他引:2
A new acidic sphingoglycolipid has been isolated from a Gram-negative, glucose-non-fermentative (obligatory aerobic) bacterium, Flavobacterium devorans ATCC 10829, by thin-layer chromatography on silica gel after mild alkaline hydrolysis of the cellular lipids. Chemical degradation studies, thin-layer chromatographic behavior, IR and mass-spectrometric analysis of the original and reduced glycolipid with LiA1H4 revealed that the lipid contained glucuronic acid, long-chain bases, and fatty acids in a molar ratio of approximately 1:1:1. The major long-chain bases were identified by gas chromatography-mass spectrometry as dihydrosphingosine (d-18 :0) and longer homologues, while the N-acyl group was exclusively 2-hydroxy myristic acid. The most probable structure of this glycolipid appeared to be a ceramide glucuronic acid (N-acyl dihydrosphingosine 1-glucuronic acid). 相似文献
15.
Long-chain bases were liberated from a crude mixture of sphingolipids from whole tissue of the fresh-water bivalve C. sandai, and conversion of the bases into N-acetyl-0-trimethylsily derivatives was accomplished. The derivatized bases were analyzed by combined gas-liquid chromatography and mass spectrometry. A portion of the sphingolipids was subjected to catalytic hydrogenation from whch saturated long-chain bases (sphinganines) were obtained. The saturated bases were oxidized with lead tetra-acetate and the aldehydes produced were analyzed by gas-liquid chromatography. The aldehydes were further oxidized to acids with silver oxide, the resulting fatty acids methylated and also analyzed by gas-liquid chromatography. By these analyses, altogether five long-chain bases were identified, consisting of hexadeca-4-sphingenine (15%), heptadeca-4-sphingenine (2%), iso-octadeca-4-sphingenine (13%), octadeca-4-sphingenine (39%) and anteiso-noadeca-4-sphingenine (31%). So far no branches have been found in shellfish spingolipid long-chain bases. 相似文献
16.
Each of the 12 genes involved in the synthesis of glucosylceramide was overexpressed in cells of Kluyveromyces lactis to construct a strain accumulating a high quantity of glucosylceramide. Glucosylceramide was doubled by the KlLAC1 gene, which encodes ceramide synthase, and not by 11 other genes, including the KlLAG1 gene, a homologue of KlLAC1 . Disruption of the KlLAC1 gene reduced the content below the detection level. Heterologous expression of the KlLAC1 gene in the cells of Saccharomyces cerevisiae caused the accumulation of ceramide, composed of C18 fatty acid. The KlLAC1 protein preferred long-chain (C18 ) fatty acids to very-long-chain (C26 ) fatty acids for condensation with sphingoid bases and seemed to supply a ceramide moiety as the substrate for the formation of glucosylceramide. When the amino acid sequences of ceramide synthase derived from eight yeast species were compared, LAC1 proteins from five species producing glucosylceramide were clearly discriminated from those of the other three species and all LAG1 proteins. The LAC1 protein of K. lactis is the enzyme that plays a crucial role in the synthesis of glucosylceramide. 相似文献
17.
Serum sphingomyelins were analyzed by argentation chromatography of the corresponding ceramide diacetates. Six subfractions were obtained. Three of them contained 4-sphingenines in combination with saturated, trans-, or cis-monoenoic fatty acids; the remaining three contained sphingadienine, also in combination with saturated, trans-, or cis-monoenoic fatty acids. Palmitic acid was the principal fatty acid combined with 4-sphingenines, while nervonic acid was the principal fatty acid combined with sphingadienine. About 4% of the total fatty acids of sphingomyelin were trans-monoenoic. They were comprised of many positional isomers of straight-chain C(22-24) compounds. The cis-monoenoic acids made up 33% of the total acids and consisted of almost pure nervonic acid. The rest of the acids were saturated. The 4-sphingenines contained small amounts of iso-C(18) and anteiso-C(19) compounds in addition to the straight-chain C(16-18) bases. 相似文献
18.
《Biochimica et Biophysica Acta (BBA)/Lipids and Lipid Metabolism》1984,792(2):214-226
d,l-α-Fluoropalmitic acid was synthesized by tosylation of methyI-d,l-α-hydroxypalmitate, and displacement of the tosylated function by tetrabutylammonium fluoride in acetonitrile. Uptake and utilization of the compound by cultured Balb/c 3T3 cells were studied after presentation of the fluoro fatty acid analogue complexed with bovine serum albumin. A concentration of 0.28 mM had very little effect on cell growth over several days of incubation, and cell morphology was unchanged. Chromatographie and mass spectrometric analyses at 6 and 12 h of incubation showed that d,l-α-fluoropalmitic acid was taken up by the cells and incorporated without modification as a fatty acyl moiety into select lipids. Significant levels of the compound were found at 12 h in phosphatidylcholine (1.6%) and sphingomyelin (0.6%) fatty acids, but not in those of other phospholipids or neutral lipids. d,l-α-Fluoropalmitic acid represented a significant percentage of the fatty acids of neutral glycosphingolipids (1.4%) and ceramides (0.8%) by 12 h. The fluoro fatty acid was not incorporated into long-chain sphingolipid bases, and mass spectrometry failed to reveal additional carbon-2 fluorine-substituted compounds in cellular lipids. Cellular levels of triacylglycerols and phosphatidylcholine remained essentially unchanged, or were slightly increased, while amounts of ceramide and gangliosides were decreased. Comparison of labeled palmitate incorporation into sphingolipid bases and fatty acids of sphingomyelin suggested inhibition of sphingosine synthesis by the fluoro fatty acid. d,l-α-Fluoropalmitic acid inhibited the formation of palmitoyl-CoA by Balb/c 3T3 long-chain acyl-CoA synthetase in vitro. The results support involvement of CoA thiol ester-independent steps in modification of membrane lipids. 相似文献
19.
Sphingolipid metabolism in Bacteroideaceae. 总被引:6,自引:0,他引:6
W Stoffel K Dittmar R Wilmes 《Hoppe-Seyler's Zeitschrift für physiologische Chemie》1975,356(6):715-725
The lipid composition of the anaerobic Bacteroides thetaiotaomikron has been analyzed. Sphingomyelin, ceramide phosphinicoethanolamine, free even-numbered and branched chain sphingosine bases and ceramide represented about 50% of the total lipid extract. The main ester phospholipid was phosphatidylethanolamine. The alkali-stable sphingophospholipids were predominantly N-acylated with 3-hydroxypalmitic acid, whereas the ester phospholipids are preferentially substituted with normal even and odd-numbered and branched-chain fatty acids. When Bacteroides was grown in a medium supplemented with labelled palmitic acid, this fatty acid was utilized for acylation reactions and to a large extent for the de novo synthesis of sphinganine. This long-chain base was incorporated into the sphingolipids and was also present in free form. The 3-hydroxypalmitic acid present in sphingolipids is not derived from palmitic acid, since labelled palmitate did not serve as a precursor. Free sphinganine added to the culture medium was also utilized efficiently for the biosynthesis of the sphingolipids by growing Bacteroides cultures. The 3H/14C ratio in sphingomyelin and ceramide phosphinicoethanolamine is the same, when [1-14C]palmitic acid and [3-3H]sphinganine serve as precursors. Sphingomyelin, which is usually only present in higher animals, is synthesized de novo in this Bacteroides strain. 相似文献
20.
Structural investigations and biological activity of inositol sphingophospholipids from Phytophthora capsici 总被引:1,自引:0,他引:1
O Lhomme M Bruneteau C E Costello P Mas P M Molot A Dell P R Tiller G Michel 《European journal of biochemistry》1990,191(1):203-209
Inositol sphingophospholipids that protect pepper (Capsicum annuum c.v. Yolo Wonder) against pathogen have been isolated by chromatographic methods from the mycelium of Phytophthora capsici. The structure of the major compound was determined by chemical methods and mass spectrometry. Phosphodiester bond cleavage of the phospholipid by mild alkaline hydrolysis liberated a ceramide which contained a C16-sphingosine. This long-chain base was identified by gas chromatography and mass spectrometry of its trimethylsilyl derivative. One of the amide-linked fatty acids was found to be 4-hydroxy-2 docosenoic acid. Fast-atom-bombardment mass spectrometry and fast-atom-bombardment collison-induced tandem mass spectrometry were used to characterize the ceramide as N(4-hydroxy-2-docosenoyl)C16-sphingosine. These sphingolipids have a protective effect on cotyledons of young peppers against necrotic lesions induced by the pathogen P. capsici. 相似文献