Isolation and characterization of a sulfated glyceroglucolipid from alveolar lavage of rabbit.

A major acidic glycolipid of the rabbit alveolar lavage has been isolated and characterized. The isolation procedure involved extraction of lipids, column fractionation on DEAE-Sephadex and silicic acid, and thin-layer chromatography. Chemical analysis of the glycolipid revealed the presence of glucose, fatty acids, glycerol mono-ethers and sulfate. By partial acid and alkaline methanolysis, oxidation with periodate and chromium trioxide, and methylation analysis of the native and desulfated compound, the structure of this glycolipid is proposed to be: SO3H-6Glc alpha 1 leads to 6Glc alpha 1 leads to 6Glc alpha 1 leads to 6Glc alpha 1 leads to 3-1,(3)-O-alkyl-2-0-acylglycerol.     

Glyceroglucolipids of the human saliva

Seven individual glycolipids (I--VII) have been isolated from the lipid extract of human saliva. All glycolipids contained glucose, glyceryl ethers and fatty acids, and differed from each other primarily with respect to the number of glucose residues. In addition, glycolipid V contained also the sulfate ester group. The structures of these glycolipids were identified by partial acid and alkaline hydrolysis, oxidation with periodate and chromium trioxide and methylation studies, as: Glc(alpha1 leads to 3)-diglyceride (glycolipid I), Glc(alpha1 leads to 6)Glc(alpha1 leads to 3)-diglyceride (glycolipids II and III), Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 3)-diglyceride (glycolipid IV), SO3H-6Glc(alpha1 leads to 6)Glc(alpha1 leads to 3)-diglyceride (glycolipid V), Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 3)-diglyceride (glycolipid VI) and Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 6)Glc(alpha1 lead to 6)Glc(alpha1 leads to 6)Glc(alpha1 leads to 3)-diglyceride (glycolipid VII). Diglyceride portion of these compounds consists of 1-O-alkyl-2-O-acyl-glycerol with the docosanoate and glyceryl-monodocosyl being the predominant acyl and alkyl components.     

Characterization and identification of glyceryl ether diesters present in tumor cells

The previously unidentified neutral lipid present in tumor tissues has been isolated from Ehrlich ascites cells and unequivocally identified as a lipid class of glyceryl ether diesters containing various degrees of unsaturation, and ranging in approximate molecular weight from 760 to 990. The glyceryl ether diester fraction was shown to be free from neutral plasmalogens (glyceryl diacyl alk-1'-enyl ethers). The tumor lipid was subjected to saponification, transesterification, and lithium aluminum hydride reduction. The glyceryl monoethers that resulted from deacylation were the 1-isomers ranging in hydrocarbon chain length from C(12) to C(24). The predominant glyceryl ethers were the hexadecyl (49%), octadecyl (21%), and octadecenyl (14%) derivatives. Saturated and mono- and polyunsaturated fatty acids ranging in chain length from C(12) to C(24) carbon atoms were esterified to the glyceryl monoether. Gas-liquid chromatography, thin-layer chromatography, and nuclear magnetic resonance and infrared spectroscopy were used to characterize and identify the intact tumor lipid and its derived products.     

ABH-blood-group antigens and glycolipids of human saliva

The nature of ABH-blood-group antigens in saliva was investigated. Human saliva was examined serologically for ABH-blood-group activity in its native form and after various treatments. The activity of the native form persisted in the delipidated samples, but was entirely lost after alkaline degradation. The lipid portion of saliva was completely inactive in the ABH hemagglutination inhibition system. The same results were obtained when purified glycolipid fraction of saliva was used instead of whole lipid extract. Neither alkaline treatment nor excessive amounts of salivary lipids effected antigenic activity of A-active glycosphingolipids of hog gastric mucosa admixed to saliva samples before alkaline degradation and/or in presence of large amounts of salivary lipids. The isolated glycolipid fractions contained at least eight glycolipids, each of which was composed of glucose, glyceryl ethers and fatty acids and differed from others with respect to number of glucose residues. Sphingosine and sugar residues involved in formation of ABH antigenic determinants were not detected. These findings together with data on stomach secretion [1,2] led us to the conclusion that ABH-blood-group antigens of saliva are exclusively of glycoprotein nature.     

Characterization of two glucuronic acid-containing glycosphingolipids in larvae of the green-bottle fly, Lucilia caesar

Two glucuronic acid-containing glycosphingolipids were purified from larvae of the green-bottle fly, Lucilia caesar by DEAE-Sephadex and Iatrobeads column chromatography. Structures of these acidic glycolipids, glycolipids X and Y, were elucidated by means of sugar analysis, permethylation, enzymatic hydrolysis, negative-ion fast atom bombardment mass spectrometry, and NMR studies. Glycolipid X was determined to have the following structure: GlcA beta 1-3Gal beta 1-3GalNAc alpha 1-4 GalNAc beta 1-4 GlcNAc beta 1-3Man beta 1-4Glc beta 1-1 ceramide. The other acidic glycolipid, glycolipid Y contains a phosphoethanolamine residue linked through the 6-hydroxy group of the N-acetyl-glucosamine unit of glycolipid X. The ceramide moieties were composed of saturated fatty acids (16:0-22:0) and tetradeca- and hexadeca-4-sphingenines. Based on the structural similarity of the ceramide moieties it appears likely that glycolipid X is an intermediate from which glycolipid Y is synthesized by addition of a phosphoethanolamine residue.     

Characterizations of Phospholipids from Paramecium tetraurelia Cells and Cilia*,†

Phospholipids from Paramecium tetraurelia strains 51s and d,95 cultures and isolated cilia were characterized. The following classes of phospholipids were identified in whole cell lipids: the 1-alkyl-2–acylglyceryl and the 1,2–diacylglyceryl forms of phosphonylethanolamine, phosphorylethanolamine. and phosphorylcholine; cardiolipin: ceramide aminoethylphosphonate and 5 other sphingolipids: phosphatidylserine; phosphatidylinositol; and lyso derivatives of the major glycerophospholipids. Cilia lipids were rich in ether lipids, phosphonolipids. and sphingolipids. Net lipid biosynthesis did not occur, as determined by the weight of lipids extracted from culture medium compared with the weight of lipids extracted from culture medium and ciliates after 7 days of growth. Total lipids/cell decreased with culture age. changes in the neutral lipid fraction accounting for the major decrease. Phospholipid class distributions changed with culture age—the glyceryl phosphorylethanolamine and choline content of cells decreased, while the glyceryl ohosphonylethanolamine content remained relatively constant: hence, the ratio of phosphonolipids to total phospholipids increased. All fatty acids observed in total lipids from cells and cilia were also present in the glycerophospholipids. Total lipids from cilia contained a greater percent of polyunsaturated fatty acid than those of whole cells. Whole cells and cilia glyceryl phosphonolipids contained up to 93% eicosatetraenoic plus eicosapentaenoic fatty acids. The enrichment of phosphonolipids in cilia accounted for most of the polyunsaturated fatty acid enrichment observed in cilia total lipids. The fatty acid composition of all major whole cell glycerophospholipid classes changed dramatically with culture age, while only small changes occurred in cilia glycerophospholipid fatty acids.     

Isolation and characterization of a neutral glycosphingolipid from the epimastigote form of Trypanosoma mega

A glycosphingolipid fraction from Trypanosoma mega was isolated after acetylation and was further purified on a silicic acid column. Final purification was by preparative thin-layer chromatography. The carbohydrate components of the glycolipid were fucose and galactose in approximately equimolar amounts. The neutral glycolipid of T. mega has a sphingosine base composition that consists of sphingosine and traces of dihydrosphingosine. Fatty acids forming amide groups with the sphingosine bases were analyzed by gas-liquid chromatography-mass spectrometry and are a mixture of normal and alpha-hydroxy fatty acids. Normal C16:0, C18:0, and 2-hydroxy C18:0 are the predominant fatty acids.     

Interleukin-2 causes an increase in saturated/monounsaturated phosphatidic acid derived from 1,2-diacylglycerol and 1-O-alkyl-2-acylglycerol.

Phosphatidic acid generation through activation of diacylglycerol kinase alpha has been implicated in interleukin-2-dependent T-lymphocyte proliferation. To investigate this lipid signaling in more detail, we characterized the molecular structures of the diradylglycerols and phosphatidic acids in the murine CTLL-2 T-cell line under both basal and stimulated conditions. In resting cells, 1,2-diacylglycerol and 1-O-alkyl-2-acylglycerol subtypes represented 44 and 55% of total diradylglycerol, respectively, and both showed a highly saturated profile containing primarily 16:0 and 18:1 fatty acids. 1-O-Alk-1'-enyl-2-acylglycerol represented 1-2% of total diradylglycerol. Interleukin-2 stimulation did not alter the molecular species profiles, however, it did selectively reduce total 1-O-alkyl-2-acylglycerol by over 50% at 15 min while only causing a 10% drop in 1,2-diacylglycerol. When radiolabeled CTLL-2 cells were challenged with interleukin-2, no change in the cellular content of phosphatidylcholine nor phosphatidylethanolamine was observed thereby ruling out phospholipase C activity as the source of diradylglycerol. In addition, interleukin-2 failed to stimulate de novo synthesis of diradylglycerol. Structural analysis revealed approximately equal amounts of 1,2-diacyl phosphatidic acid and 1-O-alkyl-2-acyl phosphatidic acid under resting conditions, both containing only saturated and monounsaturated fatty acids. After acute (2 and 15 min) interleukin-2 stimulation the total phosphatidic acid mass increased, almost entirely through the formation of 1-O-alkyl-2-acyl species. In vitro assays revealed that both 1,2-diacylglycerol and 1-O-alkyl-2-acylglycerol were substrates for 1,2-diacylglycerol kinase alpha, the major isoform in CTLL-2 cells, and that the lipid kinase activity was almost totally inhibited by R59949. In conclusion, this investigation shows that, in CTLL-2 cells, 1,2-diacylglycerol kinase alpha specifically phosphorylates a pre-existing pool of 1-O-alkyl-2-acylglycerol to form the intracellular messenger 1-O-alkyl-2-acyl phosphatidic acid.     

Lipids of Leishmania promastigotes.

A chromatographic analysis of lipids of cultured promastigotes of Leishmania donovani, L. braziliensis, L. mexicana, L. tropica, L. enriettii, L. hertigi, L. adleri, and L. tarentolae showed that total lipids were 2--15% of dry wt, and neutral and polar lipids were 14--55% and 45--86% of total lipids. Major lipid classes were as follows: sterol ester, triacylglycerol, sterol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylcholine. Predominant fatty acids were 18:2 (n - 6) greater than 18:3 (n - 3) greater than 18:1 (n - 9) greater than 18:0 greater than 22:6 (n - 3) greater than 22:5 (n - 6) greater than 16:0 greater than 14:0 greater than 18:4 (n - 3) greater than 20:3 (n - 3). Some remarkable distributions of fatty acids among the phospholipid fractions were observed, as follows: diphosphatidylglycerol 18--33% 22:6 (n - 3); phosphatidylinositol 31--68% 18:1 (n - 9); phosphatidylcholine 13--41% 18:3 (n - 3). Alk-l-enyldiacyl glycerols, and alk-l-enylacyl and alkylacyl forms of phosphatidylethanolamine and of phosphatidylinositol were found, and their glyceryl ethers and fatty adehydes analyzed. Notable in the phosphatidylethanolamine of some leishmanias was a cyclopropane fatty acid (4--11%), identified as cis-9,10-methylene octadecanoic acid by chromatographic, and by mass and proton resonance spectrometric analyses. The comparative biochemistry of the cyclopropane fatty acid, characteristic of many prokaryotes, and of alpha-linolenic acid, characteristic of photosynthetic plants, are commented upon.     

Isolation and characterization of a novel Forssman active acidic glycosphingolipid with branched isoglobo-, ganglio-, and neolacto-series hybrid sugar chains

Equine kidney and spleen contain a Forssman active glycosphingolipid, and the structure of this glycolipid has been reported to be that of a globopentaosylceramide (GalNAcalpha-1,3GalNAcbeta-1,3Galalpha-1, 4Galbeta-1,4Glcbeta-1,1'Ceramide). We found that equine kidney contains several other anti-Forssman antibody-reactive glycosphingolipids. One of these acidic Forssman active glycosphingolipids was isolated and characterized by means of NMR, mass spectrometry, permethylation studies, and TLC-immunostaining. This glycolipid contains three moles of galactose, one mole of glucose, three moles of N-acetylgalactosamine, one mole of N-acetylglucosamine, and one mole of N-acetylneuraminic acid, and is stained on TLC with anti-Forssman antibodies and anti-GM2 ganglioside antibodies. HOHAHA and ROESY experiments and permethylation studies showed this glycolipid oligosaccharide to be branched at the innermost galactose; one chain has an isoglobo structure with a terminal Forssman disaccharide and the other chain is branched through the linkage of N-acetylglucosaminebeta-1,6 to the inner galactose. The nonreducing end of the GM2 trisaccharide is linked to this glucosamine. The structure of the oligosaccharide of the glycolipid presented here is a novel type, having branched isoglobo-, ganglio-, and neolacto-series oligosaccharides. Mass spectrometric analyses indicated the ceramide moiety of the glycolipid to be composed predominantly of hydroxy fatty acids (C20:0, C22:0, C23:0, C24:0, and C25:0) and hydroxysphinganine. GalNAcalpha-1,3GalNAcbeta-1,3Galalpha-1,3[GalNAcbet a-1, 4(NeuAcalpha-2,3)Galbeta-1,4GlcNAcbeta-1,6]Galbeta+ ++-1,4Glcbeta-1, 1'Ceramide     

Interrelationships among the ethanolamine phosphatides in myelinating rat brain

Abstract— —The ethanolamine phosphatide fraction was isolated from rat brain at 17, 19, and 22 days of age. Analysis by gas-liquid chromatography of the liberated fatty aldehydes and alkyl glyceryl ethers demonstrated a chain length composition quite distinct from that of the fatty acids in the comparable 1(3)-position of the diacyl phosphatides. [1-¹⁴C]-Acetate was administered intraperitoneally to 17-day-old rats. With the exception of the polyunsaturated fatty acids, isotope was readily incorporated into the individual side chains of the 1- and 2-positions of the glycerol moiety. Time studies revealed no readily discernible precursor-product relationships among the linkages in question. Therefore, although the long chain precursors for the alkenyl and alkyl ethers may be related by biosynthetic interconversion, the isotope data are suggestive of independent pathways of biosynthesis for the alkenyl ether, alkyl ether, and ester linkages.     

Isolation and characterization of a monosialosylgangliopentaosyl ceramide from Xenopus laevis oocyte.

A monosialosylgangliopentaosyl ceramide was isolated from Xenopus laevis oocytes. It represented 5.8% of the total acidic glycosphingolipids. From the results of sugar-composition analysis, enzymatic hydrolysis, permethylation analysis, and negative ion fast atom bombardment mass spectrometry, the structure of the ganglioside was determined to be as follows: [sequence: see text] The predominant species of fatty acids were alpha-hydroxy fatty acids, h22:0, h24:0, and h24:1. The long chain bases of this ganglioside consisted mainly of d18:1 sphingosine and phytosphingosine. Other acidic glycolipids were also characterized. The most abundant component of acidic glycolipids was sulfatide, which represented 85.7% of the total acidic glycolipid mixture. GM3, GM2, GM1a, and GD1a were also detected.     

A family of glycoinositol phospholipids from Leishmania major. Isolation, characterization, and antigenicity

The glycolipids of the protozoan Leishmania major strain LRC-L119 belong to a class of glycoinositol phospholipids (GIPL) that show partial structural homology to the phosphatidylinositol-containing glycolipid membrane anchors of several eukaryotic proteins and the lipid moiety of L. major lipophosphoglycan. The GIPLs were the only glycolipids detected and were purified by octyl-Sepharose and thin layer chromatographies. Analysis of the native and dephosphorylated glycolipids (GIPLs 1-6) by gas chromatography-mass spectrometry revealed that the glycan moieties have between 4 and 10 saccharide residues and all contain mannose, galactose, and non-N-acetylated glucosamine. Some of the GIPLs also contain glucose (GIPL-6) and hexose monophosphate residues (GIPL 4-6). The presence of an inositol phospholipid moiety in all the GIPLs is indicated by the identification of 1 myo-inositol monophosphate residue/molecule and their susceptibility to phosphatidylinositol-specific phospholipase C. However, heterogeneity in the lipid moieties is indicated by differences in the compositional analysis and the behavior of the GIPLs on the thin layer chromatography after mild alkali hydrolysis or phospholipase A2 treatment. These results demonstrate that GIPLs 1-4 contain 1-alkyl-2-acylglycerol composed of saturated unbranched alkyl chains with carbon chain lengths of 18-26 and acyl chains of myristate, palmitate and stearate, whereas GIPL-5 and -6 contain lyso-alkylglycerol composed of mainly C24:0 and C26:0 alkyl chains. Analysis of the products of nitrous acid deamination demonstrates that these glycerolipids are present as alkylacylphosphatidylinositol (GIPLs 1-4) and 1-O-alkylglycerophosphoinositol (GIPL-5 and -6), respectively. GIPL-2 and -3 are labeled on the surface of living promastigotes with galactose oxidase/NaB[3H]4. These GIPLs also react with three monoclonal antibodies that recognize the surface of promastigotes and amastigotes of L. major and other Leishmania spp.     

Sphingolipid composition of human platelets

Total lipid extracts from washed trypsinized human platelets were fractionated into neutral lipids, glycosphingolipids, and phospholipids by silicic acid chromatography. The concentrations and chemical structures of the neutral and acidic glycosphingolipids were then studied in detail. On the basis of sugar molar ratios, studies of permethylation products, and the action of stereospecific glycosidases on the lipids, identifications were made of four neutral glycosphingolipids. Lactosylceramide was the most abundant type and accounted for 64% of the total neutral glycolipid mixture. The major fatty acids of the lactosylceramide were 20:0, 22:0, 24:0, and 24:1; the major long-chain base was 4-sphingenine. The platelets were surprisingly rich in a ceramide fraction, which represented 1.3% of the total platelet lipids. It had a different fatty acid composition than the neutral glycosphingolipid and ganglioside fractions. Hematoside was also isolated from the total lipid fraction of platelets; the neuraminic acid component was N-acetylneuraminic acid. Treatment of platelets with trypsin, chymotrypsin, or thrombin increased the yield of hematoside as compared with a control, while the level of ceramides was not changed. It was concluded that the platelets are similar to leukocytes, liver, and spleen in that lactosylceramide and hematoside are the principal neutral and acidic glycosphingolipids. The presence of a relatively high proportion of ceramide in platelets may be a unique characteristic of this cellular fraction of blood.     

The isolation and partial characterization of glycolipids of normal human leucocytes

1. The lipids of purified human leucocytes were extracted with chloroform-methanol and the extract was washed with water. Glycolipids, isolated by Florisil chromatography, were subjected to mild alkaline hydrolysis and the alkali-resistant fraction was fractionated on a silicic acid column. 2. Three classes of glycolipid were separated. The less polar, containing 3.6% of the total glycolipid hexose as galactose, was tentatively identified as ceramide monohexoside. The major glycolipid fraction was characterized as ceramide dihexosides. The more polar glycolipids comprised 1.6% of the total glycolipid hexose as galactose and glucose (in the molar ratio 2:1) and were non-acidic. This class was separated as a mixture containing ninhydrin-positive glycolipids. 3. The ceramide dihexosides taken from two leucocyte preparations accounted for 15.2% and 16.4% by weight of the total lipids. 4. The carbohydrate moiety of the ceramide dihexosides contained galactose and glucose in the molar ratio 2:1. Partial acid hydrolysis and paper chromatography indicated that the hexoses are present as disaccharides, lactose being identified as one of them. 5. Palmitic acid (C(16:0)) and nervonic acid (C(24:1)) were the major fatty acids of this glycolipid. Hydroxy fatty acids were not detected.     

Factors affecting surface expression of glycolipids: influence of lipid environment and ceramide composition on antibody recognition of cerebroside sulfate in liposomes

The reactivity of the acidic glycolipid cerebroside sulfate (CBS) with antibody was studied as a function of its lipid environment in vesicles and of its ceramide composition. The lipid environment was varied by using phosphatidylcholine of varying chain length with cholesterol in a phosphatidylcholine:cholesterol:cerebroside sulfate molar ratio to glycolipid of 1:0.75:0.1. The ceramide structure of CBS was varied by using synthetic forms containing palmitic acid, lignoceric acid, or the corresponding alpha-hydroxy fatty acids. Reactivity with antibody was determined by measuring complement-mediated lysis of the vesicles containing a spin-label marker, tempocholine chloride. The data were analyzed by a theoretical model which gives relative values for the dissociation constant and concentration of antibodies within the antiserum which are able to bind to the glycolipid. If the phosphatidylcholine chain length was increased, increasing the bilayer thickness, only a small population of high-affinity antibodies were able to bind to cerebroside sulfate, suggesting decreased surface exposure of the glycosyl head group. A larger population of lower affinity antibodies were able to bind to it in a shorter chain length phosphatidylcholine environment. However, if the chain length of the cerebroside sulfate was increased, it could be recognized by more antibodies of lower affinity than the short chain length form, suggesting that an increase in chain length of the glycolipid increased surface exposure. Hydroxylation of the fatty acid inhibited antibody binding; only a smaller population of higher affinity antibodies was able to bind to the hydroxy fatty acid forms.(ABSTRACT TRUNCATED AT 250 WORDS)     

Glycolipid components of epimastigote forms of Trypanosoma cruzi

Glycosphingolipids were isolated from a lipid extract of epimastigote forms of Trypanosoma cruzi via Florisil and silicic acid column chromatography. The carbohydrate components of neutral glycolipid consisted of mannose and galactose in a ratio of 1:2. The fatty acids of the glycolipid were analyzed by gas liquid chromatography-mass spectrometry (g.l.c.-m.s.). Normal and 2-hydroxy fatty acids were found. The sphingosine bases were C18 dihydrosphingosine and 17-methyl sphingosine.     

Pyruvylated glycolipids from Mycobacterium smegmatis. Nature and location of the lipid components

The dipyruvylated glycolipid from Mycobacterium smegmatis (Saadat, S., and Ballou, C.E. (1983) J. Biol. Chem. 258, 1813-1818) has been shown to have the following structure in which FA1 is tetra- or hexadecanoic acid and FA2 is 2,4-dimethyl-2-eicosenoic acid. (formula; see text) The fast atom bombardment mass spectrum showed two major ions [M - H]- at m/z 1511 and 1539 (Mr 1512 and 1540) in a ratio of 1.4:1, suggesting that the glycolipid was a mixture of homologs that differed in fatty acid composition by 2 methylene groups. Analysis revealed C14, C16, and C22 fatty acids in ratios of 0.6:0.4:1.0, indicating that 60% of the molecules contained a C14 and C22 fatty acid whereas 40% contained a C16 and C22 fatty acid. The fragmentation pattern showed that a single glucose unit along with the smaller fatty acid could be lost to yield a tetrasaccharide with attached C22 fatty acid, and a second fragmentation yielded a trisaccharide containing 2 pyruvic acids but without attached fatty acid. The C14 and C16 fatty acids were identified as myristic and palmitic acid, whereas the C22 fatty acid was 2,4-dimethyl-2-eicosenoic acid. Precise localization of the fatty acids came from periodate oxidation and methylation analysis.     

Glycolipids and fatty acids of two dog kidney cell lines.

Glycolipid and fatty acid compositions were studied in whole cells and plasma membranes from two dog kidney cell lines (Madin-Darby and SV40-transformed cells) grown in monolayer and suspension cultures. Glycolipids, which account for 5% or less of the total lipids in dog kidney cells, were substantially increased in plasma membranes relative to whole cells. Sialoglycolipids more complex than a Tay-Sachs-like ganglioside were not found in any whole-cell or plasma-membrane preparation of this study. Dog kidney cells transformed by SV40 virus contained primarily a less complex sialoglycolipid, haematoside. Neutral glycolipids comprised 26-43% of the total glycolipid content in Madin-Darby preparations, whereas in transformed cells and membranes neutral glycolipids constituted only 1-22% of the total glycolipid content. Ceramide trihexoside was found in Madin-Darby cultures, but not in transformed cultures. The values for short-chain fatty acids from neutral glycolipids and for saturated fatty acids were generally higher than the values for these fatty acids in calf serum.     

Isolation and Characterization of a Neutral Glycosphingolipid from the Epimastigote Form of Trypanosoma mega1

ABSTRACT. A glycosphingolipid fraction from Trypanosoma mega was isolated after acetylation and was further purified on a silicic acid column. Final purification was by preparative thin-layer chromatography. The carbohydrate components of the glycolipid were fucose and galactose in approximately equimolar amounts. The neutral glycolipid of T. mega has a sphingosine base composition that consists of sphingosine and traces of dihydrosphingosine. Fatty acids forming amide groups with the sphingosine bases were analyzed by gas-liquid chromatography-mass spectrometry and are a mixture of normal and α-hydroxy fatty acids. Normal C_16:0, C_18:0, and 2-hydroxy C_18:0 are the predominant fatty acids.