Nonhydroxy Fatty Acids Research Articles

Characterization of the binding of Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) to glycosphingolipids, using a solid-phase overlay approach.

Actinomyces naeslundii (ATCC 12104) and Actinomyces viscosus (ATCC 19246) were radiolabeled externally (125I) or metabolically (35S) and analyzed for their ability to bind glycosphingolipids separated on thin layer chromatograms or coated in microtiter wells. Two binding properties were found and characterized in detail. (i) Both bacteria showed binding to lactosylceramide (LacCer) in a fashion similar to bacteria characterized earlier. The activity of free LacCer was dependent on the ceramide structure; species with 2-hydroxy fatty acid and/or a trihydroxy base were positive, while species with nonhydroxy fatty acid and a dihydroxy base were negative binders. Several glycolipids with internal lactose were active but only gangliotriaosylceramide and gangliotetraosylceramide were as active as free LacCer. The binding to these three species was half-maximal at about 200 ng of glycolipid and was not blocked by preincubation of bacteria with free lactose or lactose-bovine serum albumin. (ii) A. naeslundii, unlike A. viscosus, showed a superimposed binding concluded to be to terminal or internal GalNAc beta and equivalent to a lactose-inhibitable specificity previously analyzed by other workers. Terminal Gal beta was not recognized in several glycolipids, although free Gal and lactose were active as soluble inhibitors. The binding was half-maximal at about 10 ng of glycolipid. A glycolipid mixture prepared from a scraping of human buccal epithelium contained an active glycolipid with sites for both binding specificities.

Characterization of the binding of propionibacterium granulosum to glycosphingolipids adsorbed on surfaces. An apparent recognition of lactose which is dependent on the ceramide structure.

The binding properties of a strain of Propionibacterium granulosum derived from human skin was investigated with reference to glycosphingolipids separated on thin layer chromatograms or coated in microtiter wells using externally (125I) and metabolically [( 35S]methionine) labeled bacteria. Binding was found to lactosylceramide (LacCer; Gal beta 1-4Glc beta 1-Cer) but not to glycolipids lacking the lactose sequence (i.e. Glc beta 1-Cer, Gal beta 1-Cer or Gal alpha 1-4Gal beta 1-Cer). In microtiter wells, binding occurred at 50 ng and became half-maximal at the theoretical value for a monomolecular layer of LacCer (i.e. 100-200 ng/well). The bacteria also bound to glycolipids with various substitutions (e.g. GalNAc beta 1-4, Gal beta 1-3GalNAc beta 1-4, Fuc alpha 1-2Gal beta 1-3GalNAc beta 1-4, Gal alpha 1-3, GlcNAc beta 1-3, Gal beta 1-3GlcNAc beta 1-3, Gal beta 1-4GlcNAc beta 1-3, and Gal beta 1-3(Fuc alpha 1-4)GlcNAc beta 1-3) at the Gal of LacCer, although only those species with GalNAc beta 1-4 or Gal beta 1-3GalNAc beta 1-4 were as active as LacCer itself. Glycolipids with other additions (e.g. Gal alpha 1-4 and NeuAc alpha 2-3) were negative. For unsubstituted LacCer, the binding required either a trihydroxy base or 2-hydroxy fatty acid, specifying the epithelial type of ceramide; LacCer composed of a dihydroxy base and nonhydroxy fatty acid was negative. This is interpreted as indicating that the proper presentation of the binding epitope depends on the ceramide structure. The relevance of this to biological membranes has not yet been established. Neither free lactose (up to 20 mg/ml) nor lactose-bovine serum albumin (5 mg/ml) prevented the binding of bacteria to LacCer, two facts that support the solid-phase binding data demonstrating a low affinity binding and the crucial importance of a particular lactose epitope.

Identification of pentahydroxystearic acid-containing taurolipid (taurolipid C) isolated from Tetrahymena thermophila

A pentahydroxystearic acid-containing taurolipid (taurolipid C) was found in cells of Tetrahymena thermophila. The lipid accounted for about 1.2% of the total taurolipids of the cells. The lipid was subjected to mild alkaline and methanolic hydrochloric acid hydrolyses, and the structures of the hydrolyses products were identified by mass and nuclear magnetic resonance spectrometries, as taurine, non-hydroxy fatty acid and 2,3,7,12,13-pentahydroxystearic acd, a novel fatty acid. The NMR spectra of the intact and acetylated lipid showed that the carboxyl group of the pentahydrostearic acid was combined with the amino group of taurine, and the hydroxy group at C-3 was esterified with non-hydroxy fatty acids. From these results, the pentahydroxystearic acid-containing taurolipid (taurolipid C) isolated from T. thermophila was identified as 2-(3-acyloxy-2,7,12,13-tetrahydroxyoctadecanoylamino)ethanesulfonic acid.

Monoclonal antibody to galactosylceramide: discrimination of structural difference in the ceramide moiety

A mouse monoclonal antibody (mAb) was developed against monohexaosylceramide. This mAb differentially reacted on thin-layer chromatograms with 3 types of galactosylceramide (GalCer) obtained from bovine brain. Structural analysis of the 3 glycolipids revealed that they consisted of the same galactose and sphingosine but of apparently different fatty acids. Among the 3 GalCers, the mAb reacted with two GalCers which contained α-hydroxy fatty acids, but not with GalCer composed of nonhydroxy fatty acids. These findings suggest not only that the mAb discriminated the fatty acid composition in the ceramide moiety of GalCer, but also that the ceramide structure defines the immunological epitope as it is known to do for the carbohydrate moiety of glycosphingolipid.

Fatty Acid Analysis of Galactolipids and Ganglioside in the Brains of Four Cases of Nasu‐Hakola Disease

A study was conducted on the fatty acid composition of cerebroside, sulfatide and ganglioside in the brains of 4 cases of Nasu-Hakola disease. The percentage of short carbon chain (C.16-C.18) nonhydroxy fatty acids of sulfatide in the cortex was much higher than that of the control and long-chain (C.24-) fatty acids showed a lower percentage. Sulfatide in the white matter was of the same tendency. The percentage of C.16:0 palmitic acid of ganglioside in the cortex was much larger than that of the control. Referring to the fatty acid composition of lipids in the literature, abnormalities of the fatty acid concentration, namely a high percentage of short-chain fatty acids of sulfatide and ganglioside in the cerebral cortex of the present cases, were confirmed.

Structural and compositional difference in the neutral glycolipids between epithelial and non-epithelial tissue of the mouse small intestine

Five major neutral glycolipids, GL-1-GL-5, were isolated from the the mouse small intestine. Their structures and distribution were determined by permethylation analysis, sequential degradation with exoglycosidases and/or immunohistochemistry. The molar ratio of GL-1, GL-2, GL-3, GL-4 and Gl-5 in the whole small intestine was 1:0.04:0.03:0.42:0.02. The structures of GL-1 and GL-4 present in epithelial cells were reported previously to be glucosyl ceramide and asialo G M1, respectively (Umesaki, Y., Suzuki, A., Kasama, T., Tohyama, K., Mutai, M. and Yamakawa, T. (1981) J. Biochem. 90, 1731–1738). GL-5, also present in the epithelial cells, was fucosyl asialo G M1, and fucose was shown to be linked to terminal galactose of asialo G M1 in the manner of α(1–2) bond. GL-2 and GL-3, present in the residual tissue after scraping the mucosa, were determined to be globoside and Forssman glycolipid, respectively. Both globoside and Forssman glycolipid of the non-epithelial tissue had non-hydroxy fatty acid (C 16–C 24) in combination with sphingosine (C 18) as the ceramide components, in contrast with the ceramide structures of the epithelial glycolipids, which contained α-hydroxy fatty acids in combination with phytosphingosine. Immunohistochemical staining using anti-glycolipid antibodies confirmed the distribution of asialo G M1 and fucosyl asialo G M1, and Forssman glycolipid in the epithelial and non-epithelial tissue, respectively.

Dexamethasone-induced alterations in the glycosphingolipids of rat kidney.

To determine whether glucocorticoids would influence the glycosphingolipid composition of the rat kidney, male albino rats of the Sherman strain were subcutaneously administered dexamethasone (100 micrograms/100 g body wt/day) or diluent for four days. The compositions of ceramide and of acidic and neutral glycosphingolipids of the kidneys of these animals were then examined and compared. The results demonstrated that dexamethasone administration: 1) increased the content of ceramide and of acidic and neutral glycosphingolipids in kidney; 2) increased the relative percentage of globotriaosyl- and globotetraosyl-ceramide, but decreased the relative percentages of glucosylceramide; 3) decreased the relative percentages of GM3 and increased other gangliosides; 4) increased the relative percentages of N-glycolylneuraminic acid in GM3; 5) did not appear to influence significantly the long-chain bases of the major glycosphingolipids; and 6) altered the relative percentages and chain length of the hydroxy and nonhydroxy fatty acids of the major acidic and neutral glycosphingolipids in this tissue. The data show that dexamethasone administration induces quantitative and qualitative changes in the glycosphingolipids of the rat kidney.

Structures of the eight- to nine-sugar glycolipids of human blood group a erythrocytes

Two glycolipid fractions, isolated in 1975 from blood group A 1 erythrocytes and shown on the basis of direct-inlet mass spectrometry to contain eight- and nine-sugar A-type sequences, have been reinvestigated by fast-atom-bombardment mass spectrometry and overlay analysis with selected monoclonal anti-A antibodies. The presence of three separate glycolipids was concluded, consistent with a common paragloboside backbone [β- d-Gal p-(1→4)-β- d-Glc pNAc-(1→3)-β- d-Gal p-(1→4)- d-Glc] and a typical erythrocyte ceramide component (sphingosine, and 22-, 23-, 24-, and 25-carbon nonhydroxy fatty acids). It is proposed that they carry A determinants based on Type 1 [β- d-Gal p-(1→3)-β- d-Glc pNAc], Type 2 [β- d-Gal p-(1→4)-β- d-Glc pNAc], and Type 3 [β- d-Gal p-(1→3)-α- d-Gal pNAc] chains, respectively. The Type 1 (eight sugars) and Type 3 (nine sugars) glycolipids appeared in mixtures of both the native and the acetylated form. The existence of Type 1 glycolipid, which appears to be a genuine erythrocyte glycolipid as concluded from the ceramide composition, had been predicted earlier by other workers.

Isolation and structural characterization of a diacyltaurolipid in cells of Tetrahymena mimbres

A diacyltaurolipid was found in cells of Tetrahymena mimbres (formerly Tetrahymenas pyriformis NT-1). The lipid accounted for about 0.05% of the total lipids of the cells, and was composed of taurine (1 equiv.), 3,7,13-trihydroxystearic acid (1 equiv.) and non-hydroxy fatty acids (2 equiv.). By mild alkaline hydrolysis, non-hydroxy fatty acids (2 equiv.) and 2-(3,7,13-trihydroxyoctadecanoyl)aminoethanesulfonic acid were obtained. For determination of the positions of the ester bonds of the lipid, the free hydroxy group of the intact lipid was converted to a ketone, and the esterified hydroxy groups were acetylated after methanolic hydrochloric acid hydrolysis. By mass and nuclear magnetic resonance spectrometry, the structure of the derivative was identified as methyl 3,7-diacetoxy-13-oxooctadecanoate. From these results, the diacyltaurolipid isolated from T. mimbres was identified as 2-(3,7-diacyloxy-13-hydroxyoctadecanoyl)aminoethanesulfonic acid (7-acyltaurolipid A). This structure suggests that the diacyltaurolipid may be formed by acylation of taurolipid A.

Studies on the binding of bacteria to glycolipids Two species of Propionibacterium apparently recognize separate epitopes on lactose of lactosylceramide

Two species of Propionibacterium were analysed regarding their binding to glycosphingolipids. Bacteria were labeled with 125I and selective interaction with glycolipids on thin-layer chromatograms was revealed by autoradiography. The carbohydrate site in common for active molecular species appeared to be lactose. The two bacteria differed, however, in the overall binding pattern on the chromatogram, probably due to recognition of separate epitopes on lactose. P. freudenreichii bound only to lactosylceramide while P. granulosum also recognized substituted lactosylceramide: Galα1 → 3Galβ1 → 4GlcβCer, GlcNAcβ1 → 3Galβ1 → 4GlcβCer and Galβl → 3GlcNAcβ1 → 3Galβ1 → 4GlcβCer were active, but Galα1 → 4Galβ1 → 4GlcβCer was inactive. Also, there was an interesting dependence on ceramide structure in the case of lactosylceramide. P. freudenreichii bound to lactosylceramide with sphingosine and non-hydroxy fatty acids but not to species with sphingosine and 2-hydroxy fatty acids, phytosphingosine and non-hydroxy fatty acids or phytosphingosine and 2-hydroxy fatty acids. For P. granulosum the situation was reversed. This may be explained by an influence of ceramide structure on the presentation of the two lactose epitopes at the assay surface. These results were supported by curves from the binding of labeled bacteria to glycolipids coated in microtiter wells and in part by binding to glycolipid-coated chicken erythrocytes.

Interdigitated lipid bilayers of long acyl chain species of cerebroside sulfate. A fatty acid spin label study

The metastable phase behavior of semi-synthetic species of cerebroside sulfate (CBS), with hydroxy and non-hydroxy fatty acids from 16 to 26 carbons in length, was compared in Li + and K + using differential scanning calorimetry. The structure of the metastable and various stable phases formed in the presence of these two cations was investigated using a fatty acid spin label, 16-doxylstearate. A number of stable phases with successively higher phase transition temperatures and enthalpies occur in the presence of K + (see the preceding paper). Li + prevents formation of the most stable phases with the highest transition temperatures and enthalpies for all species of CBS. However, it does not prevent a transition from the metastable phase to the first stable phase of the longer chain C24 and C26 species. Furthermore, it allows C24:0h-CBS to undergo a similar transition, in contrast to a high K + concentration, which prevents it. The spin label has anisotropic motion in the metastable gel phase formed by all species of CBS on cooling from the liquid crystalline phase. The spectra resemble those in gel phase phospholipids. The spin label is partially insoluble in the most stable phases formed by all the lipids, including the unsaturated C24:1 species, preventing further elucidation of their structure using the technique. However, the spin label is soluble in the first stable phase formed on cooling by the longer chain C24:0 and C26:0-CBS in Li + and K + and by C24:0h-CBS in Li +, and is motionally restricted in this phase. The motional restriction is similar to that observed in the mixed interdigitated bilayers of asymmetric species of phosphatidylcholine and fully interdigitated bilayers formed by symmetric phospholipids. It strongly suggests that the highly asymmetric long chain species of CBS form a mixed interdigitated bilayer in their first stable gel phases while the metastable phase of these and the shorter chain lipids may be partially interdigitated. The metastable phase of C24:1-CBS is more disordered suggesting that it may not be interdigitated at all. Thus the results suggest that (i) the hydroxy fatty acid inhibits but does not prevent formation of a mixed interdigitated bilayer by long chain species of CBS, (ii) an increase in non-hydroxy fatty acid chain length from 24 to 26 carbons promotes it, and (iii) a cis double bond probably prevents any form of interdigitation. These results may be relevant to the physiological and pathological roles of these structural modifications of CBS.

Influence of structural modifications on the phase behavior of semi-synthetic cerebroside sulfate

Cerebroside sulfate (galactosylceramide I 3-sulfate) containing α-hydroxy lignoceric acid (C24:0h-CBS), nervonic acid (C24:1-CBS), or hexacosanoic acid (C26:0-CBS) was prepared by a semi-synthetic procedure and studied by differential scanning calorimetry. The phase behavior of these species in 2 M KCl was compared to that of shorter chain length hydroxy and non-hydroxy fatty acid species reported earlier. All three of the new lipids undergo metastable phase behavior similar but not identical to the other species. In addition, the metastable phase behavior of all of the non-hydroxy fatty acid species was found to be more complex than previously thought, with several phases of high transition temperatures and enthalpies possible. Fatty acid hydroxylation inhibits the transition from the metastable to some of the more stable phases. It also significantly increases the phase transition temperatures of both the metastable and stable phases indicating that it contributes to the hydrogen bonding network formed between the lipid molecules and helps overcome the lateral repulsive effect of the negatively charged sulfate. The C-15 cis double bond significantly lowers the temperature and enthalpy of the phase transition indicating that it increases the lateral separation of the lipid molecules and decreases the intermolecular hydrogen bonding interactions. However, it does not prevent formation of a more stable phase. By comparing the effect of various structural modifications reported here and earlier it could be concluded that fatty acid chain length has little effect on the phase transition temperature and enthalpy. This suggests that the forces between the lipid molecules may be dominated by head group interactions rather than interactions between the lipid chains. However, fatty acid chain length has a significant effect on the tendency of the hydroxy fatty acid species to form the more stable phase. The ease of formation of the stable phase increases with increase in chain length. Thus an increase in chain length helps overcome the kinetic barrier to stable phase formation presented by hydroxylation of the fatty acid.

Synthesis and Transport of Cerebrosides and Sulfatides in Rat Brain During Development

Synthesis and transport of nonhydroxy fatty acid (NFA)- and hydroxy fatty acid (HFA)-containing ceramides, cerebrosides, and sulfatides were studied in vivo in rat brain during development. After an intracerebral injection of [3H]serine, incorporation into these lipids of microsomal and myelin membranes was analyzed after HPLC. Distribution of amounts and incorporation of radioactivity were also determined in individual molecular species of these lipids. The results showed that HFA-ceramides and long-chain NFA-ceramides have small pool sizes and rapid turnover rates in the microsomal membranes and are preferentially utilized for the synthesis of long-chain (greater than or equal to 20:0) HFA- and NFA-galactocerebrosides of both microsomal and myelin membranes. Glucocerebrosides are not expressed in myelin and their synthesis in microsomal membranes is predominant before the onset of myelination. With development, synthesis and accumulation of HFA-cerebrosides increase over NFA-cerebrosides in both microsomal and myelin membranes. In myelin, incorporation of radioactivity into HFA-cerebrosides is even higher than that expected by transport alone from microsomal membranes and it is possible that part of the HFA-cerebrosides in myelin could be due to de novo synthesis by myelin itself. The amount of NFA- and HFA-sulfatides is about equal, both in myelin and microsomal membranes, and this relative proportion does not change with development. Similar relative rates of incorporation of radioactivity into sulfatides of microsomal and myelin membranes are consistent with the notion that both NFA and HFA sulfatides are synthesized in the microsomal (Golgi) membranes and are transported to myelin.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolation and characterization of major gangliosides from frog liver.

Four major gangliosides isolated from frog liver were characterized by compositional analysis involving GLC and GC-MS, methylation analysis, chromium trioxide oxidation, and enzymatic hydrolysis. The results revealed that the most major ganglioside in the tissue was GM4 containing N-acetylneuraminic acid and the others were GM4 containing N-glycolylneuraminic acid, GD1a, and a fucosyl ganglioside which was tentatively assigned to be alpha-galactosyl alpha-fucosyl GM1. This is the first report describing the presence of GM4 containing N-glycolylneuraminic acid. The fatty acids in both GM4 were mainly alpha-hydroxylated, and those in the fucosyl ganglioside were exclusively nonhydroxy fatty acids. The GD1a contained both nonhydroxy and alpha-hydroxy fatty acids in a ratio of about 3:2. The predominant species were 22:0, 23:0, 24:0, and 24:1 in both species of the fatty acids. The long-chain bases of these four gangliosides consisted of C18-sphingosine and C18-phytosphingosine together with significant amounts of C16 to C19 dihydroxy and trihydroxy bases with iso and anteiso structures.

Occurrence of sulfatide as a major glycosphingolipid in WHHL rabbit serum lipoproteins.

Glycosphingolipids in serum and lipoproteins from Watanabe hereditable hyperlipidemic rabbit (WHHL rabbit), which is an animal model for human familial hypercholesterolemia (FH), were analyzed for the first time in this study. Chylomicrons and very low density, low density, and high density lipoproteins contained sulfatide as a major glycosphingolipid (12 nmol/mumol total phospholipids (PL) in chylomicrons, 19 nmol/mumol PL in VLDL, 18 nmol/mumol PL in LDL, and 14 nmol/mumol PL in HDL) with other minor glycosphingolipids such as glucosylceramide, galactosylceramide, GM3 ganglioside, lactosylceramide, and globotriaosylceramide. The concentration of sulfatide as a major glycosphingolipid in WHHL rabbit serum (121 nmol/ml) was much higher than that in normal rabbit serum (3 nmol/ml). Fatty acids of the sulfatides comprised mainly nonhydroxy fatty acids (C22, 23, and 24) and significant amounts of hydroxy fatty acids (about 10%) whereas long chain bases of the sulfatides comprised mostly (4E)-sphingenine with a significant amount of 4D-hydroxysphinganine (about 10%). Furthermore, sulfatides in the liver and small intestine from normal and WHHL rabbits (where serum lipoproteins are produced) were determined to amount to 260 nmol/g liver in WHHL rabbit, 104 nmol/g liver in control rabbit, 99.6 nmol/g small intestine in WHHL rabbit, and 31.2 nmol/g small intestine in control rabbit. Ceramide portions of the sulfatides in the liver were mainly composed of (4E)-sphingenine and nonhydroxy fatty acids, while those in the small intestine were mainly composed of 4D-hydroxysphinganine and hydroxy fatty acids. These results indicated that the sulfatides of serum lipoproteins were mostly derived from the liver (90% of the total), and that the remaining sulfatides (10% of the total) might be derived from the small intestine. These two sulfatides, which have different ceramide portions, could be useful markers for metabolic and biosynthetic studies of various lipoproteins in WHHL rabbit, and thus would be helpful to further elucidate the relationship between hypercholesterolemia and atherosclerosis in the rabbit.

Determination of ganglioside non-hydroxy fatty acid and long chain base by analysis of perbenzoylated derivatives.

The non-hydroxy fatty acid and long chain base compositions from as little as 2.7 nmol of ganglioside were ascertained from perbenzoylated ganglioside derivatives. Non-hydroxy fatty acids were determined by mild alkaline methanolysis of the derivatives, followed by gas-liquid chromatography (GLC) of the methyl esters. N-acyl and N-benzoyl "gangliosides" that were generated by the methanolysis were hydrolyzed by a standard procedure that utilized aqueous acetonitrile-HCl, followed by high performance liquid chromatography (HPLC) determination of the biphenylcarbonyl derivatives with ultraviolet (UV) detection at 280 nm. A critical aspect of this procedure is a modified workup for the isolation of the biphenylcarbonyl derivatives which eliminates by-products that otherwise interfere with their separation by HPLC, especially when high sensitivity is required.

Globoseries glycosphingolipids of human meconium

Globoside and an extended globoseries glycosphingolipid with a blood group H determinant were isolated from pooled human meconia and structurally characterized by mass spectrometry, proton NMR spectroscopy, and degradational techniques using GC and GC-MS analyses. Both species contained mainly phytosphingosine and hydroxy fatty acids characteristic for human intestinal epithelial cells. With the same techniques also minor amounts of globoside with sphingosine and nonhydroxy fatty acids and a novel globoseries tetraglycosyl ceramide with a terminal N-acetylglucosamine were isolated and structurally characterized.

Biochemical and physicochemical determinations in a premyelin fraction obtained by zonal centrifugation in normal mouse and in dysmyelinating mutants (quaking, shiverer, and myelin-deficient).

Myelin and premyelin material denser than myelin were obtained from quaking (Qk), shiverer (Shi), and myelin-deficient (mld) mutant and control mice, using zonal centrifugation on zonal rotor. On these fractions, we performed biochemical analysis (lipids and fatty acid), and, in parallel, we determined the physical structure of membranes by the spin-label method. The hyperfine splitting constant (2 Tll) was used to determine the order of membranes and their rigidity, and frequency of rotation (Vc) was used to measure fluidity. In control mice, the premyelin material contained a lesser amount of sphingolipids than pure myelin, but the relative proportions between hydroxy- and nonhydroxy-cerebroside and sulfatides were similar in the premyelin material and in pure myelin. The premyelin material contained half the alkanes found in the pure myelin and much less very-long-chain fatty acids. The (2 Tll) was lower in the premyelin material, but the (Vc) was similar in myelin and premyelin material. In mutants, the amount of material recovered in the premyelin fraction was reduced in qk, and increased in both shi and mld. The relative amount of sphingolipids were normal in mld, but not in shi mutants, especially in cerebrosides formed with alpha-hydroxylated fatty acids and sulfatides formed with unsubstituted fatty acids. The absolute amounts of sphingolipids were nearly normal in both shi and mld. In the premyelin fraction from qk mutants, both relative and absolute amounts of sphingolipids were drastically altered. In percentage, cerebrosides and sulfatides formed with nonhydroxyfatty acids were dramatically reduced, and, conversely, cerebrosides and sulfatides formed with hydroxyfatty acids were increased. In terms of absolute amount, only cerebrosides and sulfatides formed with nonhydroxyfatty acids were dramatically reduced. In the premyelin fraction, polyunsaturated fatty acids were increased in shi and mld, but decreased in qk. In this mutant, lignoceric (24:0) and nervonic (24:1) acids were drastically reduced. The amount of alkanes in the premylin material from qk and mld was reduced by 50%. The shi fraction was nearly free of alkanes. The maximal apparent coupling constant (hyperfine splitting constant, 2 Tll) was not affected in the mld and qk mutant, but was reduced in the shi mutant premyelin fraction. The Vc was dramatically increased in the qk, slightly decreased in the shi, and close to control in the mld. This work provides additional data on premyelin material prepared in various neurological mutants using continuous gradients in zonal rotor.(ABSTRACT TRUNCATED AT 400 WORDS)

Glycosphingolipid patterns of fetal and adult small intestinal mucosa in the sheep

The ganglioside and neutral glycosphingolipid composition of fetal and adult sheep small intestinal mucosa were characterized and compared. Mono- and tetrahexosylceramide were the major neutral glycolipids of both fetal and adult tissue. Fetal mucosa, however, possessed a higher content of monohexosylceramide than its adult counterpart. Similarly, G D1a, G M3 and G M2 were found to be the principal gangliosides in fetal and adult tissue. Adult intestinal mucosa possessed significant amounts of G T1a not present in fetal tissue. Analysis of the hydroxy and nonhydroxy fatty acids as well as the long-chain bases of the major glycosphingolipids revealed differences between these lipophilic components of glycolipids in fetal and adult intestinal mucosa. The results, therefore, indicate that both quantitative and qualitative differences in glycosphingolipid composition exist between fetal and adult sheep small intestinal mucosa.

Tetrahydroxystearic acid-containing taurolipid isolated from Tetrahymena thermophila

The second taurine-containing lipid (taurolipid B) was found in cells of Tetrahymena thermophila. The lipid accounted for about 1.4% of the total lipids of the cells. The lipid was subjected to mild alkaline and methanolic hydrochloric acid hydrolyses, and the structures of the hydrolysis products were identified by mass and nuclear magnetic resonance spectrometry, as taurine, 2,3,7,13- tetrahydroxystearic acid and non-hydroxy fatty acids. By spin-decoupling analysis in nuclear magnetic resonance spectrometry, the structure of the taurolipid B was identified as 2-(3-acyloxy-2,7,13-trihydroxyoctadecanoyl)aminoethane-sulfonic acid. This structure shows that taurolipid B is a homologue of the first taurine-containing lipid (taurolipid A).