Structures and fatty acid compositions of neutral glycosphingolipids of human plasma

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.     

The glycosphingolipid composition and glycosyltransferase activities of the small intestinal mucosa of testosterone-treated rats

Prior studies have demonstrated that sex hormones can influence the glycosphingolipid composition of different organs, including small intestine. However, to date, the effects of testosterone on glycosphingolipids of rat small intestinal mucosa have not been examined. Experiments were conducted to examine the effect of subcutaneous administration of synthetic testosterone (500 micrograms/100 g body wt.) on the gangliosides and neutral glycosphingolipids of rat small intestinal mucosa. Their results demonstrated that testosterone administrations: (i) increased the ganglioside content including hematoside (GM3); (ii) increased the total content of neutral glycosphingolipids, which was due to the increases in glucosylceramide and globotriaosylceramide; (iii) increased the activities of cytidine 5'-monophosphate-N-acetylneuraminic acid: lactosylceramide sialyltransferase, and UDPgalactose: lactosylceramide galactosyltransferase; (iv) increased the percentage of the long chain base phytosphingosine in hematoside, glucosyl-, and globotriaosylceramide; and (v) significantly altered the fatty acid composition of each of these glycosphingolipids. These results demonstrate that administration of testosterone induces alterations in glycosphingolipid composition and glycosyltransferases activities in rat small intestinal mucosa.     

Characterization of neutral sphingolipids from chicken erythrocytes

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.     

Neutral Glycosphingolipids and Ceramide Composition of Ethylnitrosourea-Induced Rat Neural Tumors: Accumulation of Ceramide in Tumors

Abstract: Experimental rat neural tumors in offspring were induced transplacentally by a single injection of a chemical carcinogen, ethylnitrosourea, 20 mg/kg body weight, in the tail vein of the mother. The neutral glycosphingolipid, sulfatide, and ceramide composition of the tumors and the normal tissues from which the tumors originated is described. The content of nonhydroxy fatty acid (NFA) and hydroxy fatty acid (HFA) containing ceramide in all the neural tumors so far examined was significantly increased compared with the corresponding normal neural tissue. Some 8 to 18 mol% of total neutral glycolipids was as ceramide in neurinomas, oligodendrogliomas, and menin-giomas. Lactosylceramide in normal neural tissues was about 1 mol% of the total neutral glycosphingolipids. In various neural tumors lactosylceramide increased up to 8 mol%. NFA- and HFA-containing cerebrosides constitute 94–100% of the neutral glycosphingolipids in normal neural tissues. In various neural tumors the mol percent of cerebrosides was significantly reduced. A high performance liquid chromatographic method was modified to analyze simultaneously ceramides, cerebrosides, and higher neutral glycosphingolipids.     

Dexamethasone-induced alterations in the glycosphingolipids of rat proximal small-intestinal mucosa

Prior studies have demonstrated that glucocorticoids can influence the structure and function of several different organs, including the small intestine. However, to date, the effects of glucocorticoids on the glycosphingolipids of the rat small intestinal mucosa have not been examined. In the present experiments, male albino rats of the Sherman strain were subcutaneously administered dexamethasone (100 micrograms/100 g body wt. per day) or diluent for 4 days, and the ceramide, acidic and neutral glycosphingolipid compositions of the proximal small intestine of these animals were examined and compared. The results of these studies demonstrate that dexamethasone administration: (1) increased the content and relative percentage of hematoside (GM3) in this tissue; (2) increased the percentage of N-glycoylneuraminic acid of hematoside; (3) decreased the percentage of the long-chain base phytosphingosine of hematoside, glucosyl- and globotriaosylceramide; and (4) did not appear to influence significantly the concentration of the neutral glycosphingolipids or ceramide in this tissue. These data, therefore, indicate that dexamethasone administration induces alterations in the glycosphingolipids, particularly hematoside, of rat small-intestinal mucosa.     

The effect of thrombin induced aggregation on human platelet glycosphingolipids

Analyses were made of the glycosphingolipid composition of human platelets before and after treatment with thrombin. Within 10 min after incubation was initiated, there was approximately a two-fold increase in the concentration of hematoside. Concomitantly, the level of lactosylceramide was decreased about three-fold, and there was also a slight diminution in the ceramide levels of these cells. Platelets treated with phenylmethyl-sulfonyl fluoride and thrombin did not exhibit such an effect. These results suggest that lactosylceramide and ceramide are utilized as precursors in the biosynthesis of hematoside and that this conversion accompanies the aggregation of human platelets.     

Lipid composition of PC12 pheochromocytoma cells: characterization of globoside as a major neutral glycolipid

We have studied the lipid composition of PC12 pheochromocytoma cells cultured in the presence and absence of nerve growth factor (NGF). Neutral and acidic lipid fractions were isolated by column chromatography on DEAE-Sephadex and analyzed by high-performance thin-layer chromatography (HPTLC). The total lipid concentration was approximately 220 micrograms/mg of protein, and the concentration of neutral glycolipids was 1.6-1.8 microgram/mg of protein for both NGF-treated and untreated cells. The neutral glycolipid fraction contained a major component, which accounted for approximately 80% of the total and which was characterized as globoside on the basis of HPTLC mobility, carbohydrate analysis, fast atom bombardment mass spectrometry, and mild acid hydrolysis. The major fatty acids of globoside were C16:0 (10%), C18:0 (16%), C22:0 (23%), C24:1 (17%), and C24:0 (24%). C18 sphingenine accounted for almost all of the long-chain bases. The other neutral glycolipids were tentatively identified as glucosylceramide (15%), lactosylceramide (4%), and globotriosylceramide (4.5%). The concentration of ganglioside sialic acid was approximately 0.34 and 0.18 microgram/mg of protein for cells grown in the presence and absence of NGF, respectively. Although there was an increase in ganglioside concentration in NGF-treated cells, NGF did not produce any differential effects on the relative proportions of the individual gangliosides. Several of the gangliosides appear to contain fucose, and one of these was tentatively identified as fucosyl-GM1. Brain-type gangliosides of the ganglio series were also detected by an HPTLC-immunostaining method. However, the fatty acid and long chain base compositions of PC12 cell gangliosides (and their TLC mobility) differ from those of brain gangliosides.(ABSTRACT TRUNCATED AT 250 WORDS)     

Lipid composition of subcellular particles of human blood platelets

Human platelets can be fractionated into three main subcellular components: granules, membranes, and a soluble fraction. In this study we determined the phospholipid and neutral lipid content of the granules and membranes. Quantitative relationships between lipids and protein were examined. The fatty acid and aldehyde composition of individual phospholipids and neutral lipids was also determined. Whole platelets had a lower lipid to protein ratio than did the subcellular particles, but the basic lipid composition of the granules, membranes, and platelets was similar. The phospholipid composition of platelets and subcellular fractions was found to differ only in that granules had a lower percentage of lecithin. Each of the phospholipid classes displayed a distinctive fatty acid pattern which was the same in all fractions and in whole platelets. The major neutral lipid was free cholesterol. Cholesteryl esters, triglycerides, and free fatty acids were minor components. The molar ratio of cholesterol to phospholipid in the platelet membranes was lower than that of brain myelin and erythrocyte ghosts. Some differences in fatty acid composition of the neutral lipids of platelet fractions were found. A special lipid composition or constituent that would correlate with platelet function has not been found.     

Structural analysis of neutral glycosphingolipids from Ascaris suum adults (Nematoda: Ascaridida)

The neutral glycosphingolipid fraction from adults of the pig parasitic nematode, Ascaris suum, was resolved into four components on thin-layer chromatography. The high-performance liquid chromatography-isolated components were structurally analysed by: methylation analysis; exoglycosidase cleavage; gas-liquid chromatography/mass spectrometry; liquid secondary-ion mass spectrometry; and, in particular, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Their chemical structures were determined as: Glc(β1-1)ceramide, Man(β1-4)Glc(β1-1)ceramide, GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide and Gal(α1-3)GalNAc(β1-4)GlcNAc(β1-3)Man(β1-4)Glc(β1-1)ceramide; and were characterized as belonging to the arthro-series of protostomial glycosphingolipids. No glycosphingolipid component corresponding to ceramide tetrasaccharide was detected during these analyses. The ceramide composition of the parent glycosphingolipids was dominated by the 2-(R)-hydroxy C24:0 fatty acid, cerebronic acid, and C17 sphingoid-bases: 15-methylhexadecasphing-4-enine and 15-methylhexadecaphinganine in approximately equal proportions. The component ceramide monohexoside was characterized by an additional 15-methylhexadecaphytosphingosine. Abbreviations: CDH, ceramide dihexoside; Cer, ceramide; CMH, ceramide monohexoside; CPH, ceramide pentahexoside; CTH, ceramide trihexoside; CTetH, ceramide tetrahexoside; Hex, hexose; HexNAc, N-acetylhexosamine; HPTLC, high-performance thin-layer chromatography; LSIMS, liquid secondary-ion mass spectrometry; MALDI-TOF-MS, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; N-, Nz- and A-glyco(sphingo)lipids, neutral, neutralzwitterionic and acidic glyco(sphingo)lipids, respectively This revised version was published online in November 2006 with corrections to the Cover Date.     

Studies on the asymmetric arrangement of membrane-lipid-enveloped virions as a model system.

Lipids of BHK 21 cells (baby hamster kidney) grown in tissue culture were labelled with radioactive fatty acids. The enveloped vesicular stomatitis virus was propagated in this host cell type. The virions were purified by density gradient centrifugation. Neuraminidase treatment of the intact virions led to a complete transformation of hematoside [N-acetylneuraminosyl(alpha2-3)lactosyl(beta1-1)ceramide] into lactosylceramide, with identical labelling of the ceramide portion in hematoside of the untreated virions and the lactosylceramide of the neuraminidase-treated particles. The morphology of the virions appeared unchanged in electron micrographs, but the neuraminic-acid-free virions had a strong tendency to aggregate. The results of these studies are evidence that gangliosides are integrated exclusively into the outer lamella of the lipid bilayer in the viral envelope. It is also evident that the viral envelope is a suitable model for studies on membrane asymmetry.     

Characterization of neutral sphingolipids and gangliosides from chicken liver

The neutral sphingolipids and gangliosides were isolated from 62- and 63-day-old chicken livers and characterized. The total concentration of neutral sphingolipids was 59 nmol/g of liver, and that of gangliosides was 330 nmol/g of liver. The major neutral sphingolipids were free ceramide, galactosylceramide, glucosylceramide, lactosylceramide, galabiosylceramide, and Forssman glycolipid. Galactosylceramide was the most abundant and free ceramide was the second most abundant. The major gangliosides were sialosylgalactosylceramide (GM4) and sialosyllactosylceramide (GM3), each of which contained only N-acetylneuraminic acid as a sialic acid. Sphingosine (d18:1) was a major long-chain base in all the sphingolipids. Considerable amounts of 2-hydroxy fatty acids were present in free ceramide, galactosylceramide, and GM4.     

Lipid composition of lysosomal multilamellar bodies of male mouse urine

Previous studies from our laboratory have shown that male C57BL/6J mice excrete into the urine multilamellar lysosomal bodies that contain specific neutral glycosphingolipids. These mice excrete approximately 20-30% of their kidney glycolipids each day. The significance and function of this secretion of multilamellar lysosomal organelles is unknown. To characterize these excreted bodies further, we report here their neutral lipid and phospholipid composition. The bodies were collected by differential centrifugation, extracted with chloroform-methanol, and lipids were fractionated into neutral lipids, glycolipids, and phospholipids. The neutral lipids consisted primarily of cholesterol, dolichol, and ubiquinone. The phospholipid fraction consisted primarily of a single molecular species of phosphatidylcholine. This lipid which comprises more than 90% of the total phospholipids was found to contain 16:0 ether and C22:6 n-3 fatty acid as determined by gas-liquid chromatography-mass spectrometry. The glycosphingolipids as reported previously consisted primarily of galabiosylceramides and globotriaosylceramides. This membrane lipid composition is different from any previously reported cellular organelle.     

Glycosphingolipids from rabbit aorta, plasma, and red blood cells: effects of high cholesterol-high fat diets on fatty acid distribution and quantity of glycosphingolipids

Four glycosphingolipids were isolated from rabbit aorta, plasma, and red blood cells. They were identified, by thin-layer chromatography and by quantitative analysis of hexose and fatty acid, as cerebroside, diglycosyl ceramide, triglycosyl ceramide, and globoside. The rabbits had been maintained on a normal diet or on one of three high cholesterol diets for 180 days. The quantities of the glycosphingolipids and their fatty acid distributions were determined, and comparisons were made between the control and experimental animals. Aorta and plasma glycosphingolipids were more affected by the high cholesterol diets than were those from red blood cells. The effects on aorta and plasma glycosphingolipids were similar. The amount of cerebroside was increased in aorta and plasma in all animals in the experimental groups. The amount was also increased in red blood cells in rabbits from two of the experimental groups. The average fatty acid chain length was greater in the lipids from the experimental animals than in those from the control animals for all measured glycosphingolipids from aorta. The average chain length was also greater in cerebrosides from the experimental animals from all three tissues. Probably the most notable differences in the experimental animals were the increased 24:1/24:0 ratios and the increased concentrations of 24:2. These increases occurred in nearly all samples from plasma and aorta, but not in red blood cells. There was also an increase of total unsaturated fatty acids in aorta cerebrosides from the experimental animals. Except for the increase in 24:2, lard generally caused more deviation from normal than did cottonseed oil when the level of cholesterol in the diet was 1%.     

Characterization of major glycolipids in bovine erythrocyte membrane

Several neutral glycolipids and gangliosides were isolated from bovine erythrocyte stroma. Their structures were determined by partial acid hydrolysis, methylation analysis, periodate oxidation and CrO3 oxidation. Two major neutral glycolipids were characterized as lactosylceramide and galactosyl(alpha1--3)galactosyl(beta1--4)N-acetylglucosaminyl(beta1--3)galactosyl(beta1--4)glucosyl(beta1--1)ceramide. Two major gangliosides were N-glycolylneuraminosyl(2--3)galactosyl(beta1--4)glucosyl(beta1--1)ceramide and N-glycolylneuraminosyl(2--3)galactosyl(beta1--4)N-acetylglucosaminyl(beta1--3)galactosyl(beta1--4)glucosyl(beta1--1)ceramide. Minor glycolipids were glucosyl- and galactosylceramide, glucosamine-containing tri- and tetraglycosylceramide, glucosamine-containing disialosylhexaglycosylceramide, and gangliosides containing N-acetylneuraminic acid. The ceramide moiety of each glycolipid contained perdominantly d18:1 sphingosine, and normal fatty acids of C16:0, C22:0, C24:0, and C24:1.     

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.     

Estrogen-induced alterations of the acidic and neutral glycosphingolipids of rat kidney

In order to determine whether female sex hormones could influence the glycosphingolipid composition of the rat kidney, male albino rats of the Sherman strain were subcutaneously administered the synthetic estrogen, ethinylestradiol (5 mg/kg body wt. per day) or vehicle for 5 days, and the ganglioside, ceramide and neutral glycosphingolipid compositions of the kidneys of these animals were analyzed and compared. The results of these experiments demonstrate that estrogen treatment: (1) increased the ceramide, acidic and neutral glycosphingolipid contents of this tissue; (2) decreased the relative percentages of glucosyl- and globotetraosylceramide and hematoside (GM3), but increased the relative percentage of globotriaosylceramide and 'other' gangliosides; (3) increased the relative percentage of N-acetyl- to N-glycolylneuraminic acid in GM3; and (4) altered the long-chain bases of GM3, glucosyl- and globotetraosylceramide in this organ. These data, therefore, demonstrate that estrogen administration induces quantitative and qualitative alterations in the gangliosides, neutral glycosphingolipids and ceramide of the rat kidney. This data as well as a discussion of the possible physiological consequences of these estrogen-induced alterations in kidney glycosphingolipids serve as the basis for this report.     

Phase behavior of stratum corneum lipids in mixed Langmuir-Blodgett monolayers.

The lipids found in the bilayers of the stratum corneum fulfill the vital barrier role of mammalian bodies. The main classes of lipids found in stratum corneum are ceramides, cholesterol, and free fatty acids. For an investigation of their phase behavior, mixed Langmuir-Blodgett monolayers of these lipids were prepared. Atomic force microscopy was used to investigate the structure of the monolayers as a function of the monolayer composition. Three different types of ceramide were used: ceramide extracted from pigskin, a commercially available ceramide with several fatty acid chain lengths, and two synthetic ceramides that have only one fatty acid chain length. In pigskin ceramide-cholesterol mixed monolayers phase separation was observed. This phase separation was also found for the commercially available type III Sigma ceramide-cholesterol mixed monolayers with molar ratios ranging from 1:0.1 to 1:1. These monolayers separated into two phases, one composed of the long fatty acid chain fraction of Sigma ceramide III and the other of the short fatty acid chain fraction of Sigma ceramide III mixed with cholesterol. Mixtures with a higher cholesterol content consisted of only one phase. These observations were confirmed by the results obtained with synthetic ceramides, which have only one fatty acid chain length. The synthetic ceramide with a palmitic acid (16:0) chain mixed with cholesterol, and the synthetic ceramide with a lignoceric acid (24:0) chain did not. Free fatty acids showed a preference to mix with one of these phases, depending on their fatty acid chain lengths. The results of this investigation suggest that the model system used in this study is in good agreement with those of other studies concerning the phase behavior of the stratum corneum lipids. By varying the composition of the monolayers one can study the role of each lipid class in detail.     

Neutral glycosphingolipids in human blood: a precise mass spectrometry analysis with special reference to lipoprotein-associated Shiga toxin receptors

Shiga toxin (Stx)-producing Escherichia coli are the leading cause of hemorrhagic colitis and life-threatening extraintestinal complications in humans. Stx1 and Stx2 are transferred by yet to be delineated mechanisms from the intestine to the circulation where they injure microvascular endothelial cells. The resulting vascular lesions cause renal failure and brain damage. Because lipoproteins are potential carriers of Stx through the circulation, we investigated human lipoprotein-associated neutral glycosphingolipids (GSLs) with emphasis on high (globotriaosylceramide) and low (globotetraosylceramide) affinity Stx-receptors. TLC overlay employing Stx1, Stx2, and anti-GSL antibodies demonstrated preferential distribution of globo-series GSLs to very low- and low-density lipoproteins compared with minor association with high-density lipoproteins. Electrospray ionization quadrupole time-of-flight mass spectrometry portrayed C24:0/C24:1 and C16:0 as the major fatty acid of the ceramide moieties of Stx-receptors carrying nonvarying d18:1 sphingosine. This structural heterogeneity was also found in precursor lactosylceramide, glucosylceramide, and galactosylceramide, the last showing an exceptionally high degree of hydroxylated C24 fatty acids. Our findings provide the basis for exploring the functional role of lipoprotein-associated Stx-receptors in human blood.     

Simultaneous fractionation of four placental neutral glycosphingolipids with a continuous gradient

We describe a method for isolating milligram quantities of the four neutral glycosphingolipids, glucocerebroside, lactosylceramide, traiosylceramide, and globoside, from human placental tissue. This procedure is carried out on a silicic acid column eluted with a continuous chloroform-methanol gradient (19:1 to 4:1); the four glycosphingolipids elute as separate fractions with no need for further separation. The method is simple, rapid, and yields sufficient material to use as analytical standards for several hundred runs. The lipids have been identified by NMR spectroscopy. Placental tissue is freely available in most centers and is an excellent untapped source for these compounds. Given that lactosylceramide is not commercially available and that triaosylceramide (ceramide trihexoside) cannot be obtained in a reliable state, this technique represents an effective solution to this dilemma.     

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.