Cerebroside Research Articles

Lipid Changes during Heat Treatment of Apple Fruit

Postharvest heat treatment of apples maintains fruit firmness and reduces decay during storage. Four days at 38C are beneficial, but 1 or 2 days are detrimental. The cellular basis of these effects may involve changes in cell wall and membrane lipid metabolism. Lipids from hypodermal tissue of `Golden Delicious' apples were analyzed after 0, 1, 2, or 4 days at 38C. Major lipids included phospholipids (PL), free sterols (FS), steryl glycosides (SG), and cerebrosides (CB). Galactolipids (GL) were minor components. PL content fell ?10% after 1 day at 38C, was unchanged after 2 days, and began to rise again after 4 days. PL class composition did not change with heating, but fatty-acid unsaturation declined throughout. FS and CB content and composition changed little, whereas SG content cropped by ≈20% over 4 days. GL fell ≈50% during 1 day at 38C, with no change at days 2 or 4. A burst of PL catabolism followed by recovery of synthesis may in part explain the different effects of 1-, 2-, or 4-day heat treatments. GL loss (in plastids) may be related to the effect of heat on fruit color (yellowing).

Quantitative analysis of phospholipids from whey protein concentrates by high‐performance liquid chromatography with a narrow‐bore column and an evaporative light‐scattering detector

AbstractA procedure for separation and quantitative determination of phospholipid classes by high‐performance liquid chromatography with a narrow‐bore column and a light‐scattering detector was developed. Cerebrosides (CER), phosphatidylinositol (PI), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylcholine (PC), sphingomeyelin (SPH), and lysophosphatidylcholine (LPC) were base‐line resolved, and column life was improved due to low back pressure and low alkalinity of the solvents. Solvent consumption was reduced by 80%, and the detection limit was improved more than tenfold, compared to an analytical column. A gradient elution with pH modifier was necessary for good resolution of acidic phospholipids. A binary solvent system, consisting of A: chloroform/methanol, 80:20 and B: chloroform/methanol/water/ammonium hydroxide (20%), 60:34:6:0.25, was used. Analysis was completed in 36 min, and repeated injections of the samples were possible. The method was applied to the analysis of phospholipids from whey protein concentrates (WPC). Phospholipids in WPC (75% protein) contained (%, w/w) 3.57±0.13 CER; 18.13±1.23 Pl; 4.45±0.21 PE; 7.45±0.58 PS; 30.54±1.84 PC; 35.82±1.16 SPH; and no detectable LPC.

LIPIDS IN SUBEPIDERMAL CORTICAL TISSUE OF `GOLDEN DELICIOUS' APPLE FRUIT

Altered metabolism of membrane lipids has been proposed as a mechanism for the beneficial effects of postharvest calcium treatment on apple quality. A previous study showed that after transfer of apples stored 6 months at 0C to 20C, calcium-treated fruit exhibited slower loss of galactolipid and altered levels of sterol conjugates. The present study of lipids in “control” fruit was conducted as a prelude to further in-depth analyses of the effects of postharvest calcium and heat treatments on lipid metabolism in apples during and after cold storage. Neutral lipid, glycolipid (GL), and phospholipid (PL) fractions were obtained by column chromatography followed by TLC separation of GL and PL classes. The major GL were steryl glycosides (SG), acylated steryl glycosides (ASG), cerebrosides (CB), and mono- and digalactosyl diacylglycerols. Phosphatidylcholine (PC) > P-ethanolamine (PE) > P-irositol (PI) were the major PL. The fatty acids of PC and PE were quite similar, whereas those of PI were more saturated. CB included only 2-hydroxy fatty acids. Among the steryl lipids, free sterols > SG > ASG, with beta-sitosterol >90% of the total sterol in each.

Lipid changes in microsomes and crude plastid fractions during storage of tomato frutis at chilling and nonchilling temperatures

Mature-green tomato fruits ( Lycopersicon esculentum) were stored for four or 12 days at chilling (2°) or nonchilling (15°) temperature. Fruits stored for 12 days at 15° ripened to the turning stage, whereas fruits at 2° did not ripen. Lipids of plastid and microsomal membrane fractions from pericarp tissue were analysed at harvest and after four or 12 days of storage. After 12 days at either 15° or 2°, the ratio of phospholipids (PL) to protein in microsomes declined, with a concomitant increase in the ratios of total membrane sterols (TMS) and cerebrosides (CB) to PL. The TMS:PL and CB:PL ratios also increased in crude plastid fractions. In both microsomes and plastids, free sterols (FS) increased more at 2° than at 15°, and hence accounted for a larger percentage of the TMS (FS + acylated steryl glycosides + steryl glycosides). The ratio of stigmasterol to sitosterol in all steryl lipids, but particularly in FS, increased more at 15° than at 2°. The unsaturation index of fatty acids in PL and galactolipids generally increased slightly during storage at both 15° and 2°. The ratio of phosphatidylethanolamine to phosphatidylcholine increased in both membrane fractions at both temperatures. In plastids, the ratio of mono- to digalactosyldiacylglycerols declined substantially at 2° but not at 15°.

In vivo metabolism of fluorescent ceramide in central nervous system myelin of adult rats

The metabolism of sphingolipids in the central nervous system (CNS) has been studied in adult rats by intraventricular administration of fluorescent ceramide (CER). Rats were sacrificed at various time points post inoculation and the fluorescence of CER, cerebrosides (CB), sulfatides (SULF) and sphingomyelin (SPM) was determined in the CNS myelin and in the pellet, containing mainly microsomes, obtained by Norton myelin preparation. The incorporation of fluorescence was more in the pellet than in the myelin at all times studied. Initially the fluorescence present in the pellet was prevalently due to untransformed CER but an increase of fluorescent products with time was observed. CB was the main product up to 2 h post inoculation, then it decreased with concomitant increase of fluorescent SULF. In the myelin we did not observe differences in incorporation and transformation of fluorescent CER with time: CB was the main fluorescent product at all times studied. At 0.5 h post inoculation the fluorescence, observed by fluorescence microscope, was located in the cell lining the ventricles while after 24 h it appeared also in the paraventricular areas.

Cerebrospinal fluid and serum antiphospholipid antibodies in multiple sclerosis, Guillain-Barré syndrome and systemic lupus arythematosus

Immunoglobulins isotypes (IgG and IgM) for myelin basic protein (MBP), cerebrosides (CER), gangliosides (GANG) and cardiolipin (CARD) were detected in the cerebrospinal fluid (CSF) from 33 patients with multiple sclerosis (MS), 18 with Guillain-Barré syndrome (GBS) and 30 with systemic lupus erythematosus (SLE). In MS patients occurred positive and significant levels of IgG-MBP in 51.5% (p less than 0.05) and IgM-MBP in only 18.2%, IgG-CARD in 46.2%, as long as CER and GANG were detected in almost 20%. From serum samples of MS patients 20.6% presented IgG-MBP, while 53% showed positive levels for IgM-MBP. The CSF analysis of patients with GBS showed that 56.3% revealed IgG-MBP (p less than 0.05), 53% for IgM-MBP, 38.5% for IgG-CER and 23% for IgM-CER, while 50% of patients had IgG-CARD, as long as 31% also had IgG-GANG. The serum evaluation from 14 patients showed that 18.8% had positive concentrations of IgG-MBP and 56.3% presented IgM-MBP (p less than 0.05). Except for 50% of patients with SLE who presented positive CSF levels of IgG-CARD, only 24.1% had positive levels of IgG-MBP. We believe that the presence of antiphospholipid antibodies in CSF of the above mentioned diseases occurred as immune epiphenomena, but their appearance would permit the maintenance of and perpetuate the immune event.

The effect of hyperbaric exposure of 20 atmospheres-absolute (He-O2) on sphingoglycolipids of rat tissues.

The effect of hyperbaric exposure of helium-oxygen at 20 atmospheres-absolute (ATA) on sphingoglycolipids of rat liver, kidney, lung and spleen was studied. No changes were found in the total lipids of the tissues of rats held in ambient air, helium-oxygen mixtures at 1 ATA and 20 ATA. The amounts of three glycolipids in the spleen and the monoglycosyl ceramide in the lung were decreased in the stressed animals. There were changes in the fatty acid profiles of glycolipids between groups of animals held in ambient air and He-O2 at 1 ATA. Greater changes were observed in the amount of glycolipids from liver and kidney of animals held at 1 ATA and 20 ATA, providing additional evidence that helium can affect cellular metablism at ambient pressure. Chain elongation of fatty acids was observed in glycolipids of liver, kidney and spleen of rats exposed to helium-oxygen at 20 ATA compared to animals held in helium-oxygen at 1 ATA.

Composition of wheat‐flour lipids

AbstractLipids were extracted from a single sample of wheat flour using three solvent systems: ethanol–diethyl ether–water (2:2:1 by vol.); chloroform–methanol (2:1 by vol.); and water‐saturated n‐butanol. Analysis of the extracts and of residual lipid in the extracted flour showed that water‐saturated n‐butanol was the most efficient solvent.Wheat‐flour lipids were extracted with water‐saturated n‐butanol and separated by chromatographic procedures into individual components. The lipid classes which were isolated and studied were steryl ester, free sterol, 6‐O‐acyl steryl glucoside, steryl glucoside, triglyceride, diglyceride, monoglyceride, free fatty acid, monogalactosyl diglyceride, 6‐O‐acyl monogalactosyl diglyceride, digalactosyl diglyceride, digalactosyl monoglyceride, monoglycosyl ceramide, diglycosyl ceramide, N‐acyl phosphatidyl ethanolamine, N‐acyl lysophosphatidyl ethanolamine, phosphatidyl ethanolamine, lysophosphatidyl ethanolamine, phosphatidyl choline, lysophosphatidyl choline, phosphatidyl serine and phosphatidyl inositol. Monogalactosyl monoglyceride was also tentatively identified. The quantitative distributions of the lipid classes were determined.Monoglycosyl ceramide contained small amounts of normal fatty acids (12:0–24:0) and large amounts of 2‐hydroxy fatty acids (principally 16:0 and 20:0), with similar amounts of dihydroxy long‐chain bases (18:0 and 18:1) and trihydroxy long‐chain bases (18:0, 18:1, 19:0, 19:1, 20:0, 22:0). The principal sterols were identified as β‐sitosterol, campesterol, and C28 and C29 saturated sterols.The fatty acids in the sterol lipids were principally 16:0 (50–60%) and 18:2 (28–30%) with small amounts of 16:1, 18:0, 18:1 and 18:3. The fatty acids in all the glycerides were principally 18:2 (51–84%) with lesser amounts of 16:0, 18:0, 18:1 and 18:3.

Studies on the glycolipids and phospholipids of immature soybeans.

AbstractThe lipid of immature soybeans was extracted with chloroform‐methanol and fractions containing the glycolipids and phospholipids were separated by column chromatography. Phosphatidyl choline (PC), phosphatidyl ethanolamine (PE), phosphatidyl inositol (PI), phosphatidic acid (PA) phosphatidyl glycerol (PG), n‐acyl phosphatidyl ethanolamine (APE) and sulfolipid (SL) were identified by thin layer chromatography (TLC). Sterol glucoside (SG), esterified sterol glucoside (ESG), digalactosyl diglyceride (DGDG) and cerebrosides (CE) were isolated by TLC and identified by color reactions, chemical degradation and spectral analysis.

Factors affecting the glycosphingolipid composition of murine tissues

The effects of genetic strain, sex, age, and pathological state on the distribution and concentration of glycosphingolipids in mouse kidneys and livers were studied. The concentrations of glycosphingolipids and phospholipids in the kidneys and livers of different strains were compared. The major glycosphingolipid in the kidneys of male and female BALB/c, C3H/He, C57/BL, A, and C57xA (F(1) hybrid) mice was a sulfatide, monoglycosyl-(3-sulfate) ceramide; monoglycosyl ceramide was the major component in livers. The kidneys of males of all strains contained significant amounts of diglycosyl ceramide, but those of females contained, at most, only traces. Glycosphingolipid concentration in the male kidneys of C57/BL and C57xA (F(1) hybrid) was much higher than in the female and was also much higher than in the male kidneys of C3H/He, BALB/c, and A strains. The kidneys of "old" (36 wk) male and female C3H/He mice contained much higher proportions of monoglycosyl ceramide than 10-12-wk-old adults. The distributions of glycosphingolipids in kidneys of female C3H/He mice with BP8 ascites tumors and male C57xA (F(1) hybrid) mice with EL4 ascites tumors differed from those in the normal mice. An unknown lipid, present in all glycosphingolipid extracts from kidney and liver, was tentatively identified as cholesterol sulfate.

Substituted cerebrosides Part V. Synthesis of a dihydroceramide trihexoside

Substituted cerebrosides Part V. Synthesis of a dihydroceramide trihexoside

Chemistry of phosphatides and cerebrosides.

Chemistry of phosphatides and cerebrosides.