Cerebrosides composition

Central nervous system myelin is enriched in certain lipids. Table 4-1 lists the composition of bovine, rat, and human myelin compared to bovine and human white matter, human gray matter, and rat whole brain [1] (see Ch. 3). While there are no absolutely myelin-specific lipids, cerebroside (galactosyl ceramide) is the most typical of myelin. With the exception of early development,... 

Peripheral and central nervous system myelin lipids are qualitatively similar. However, there are quantitative differences. PNS myelin has less cerebroside and sulfatide and considerably more sphingomyelin than CNS myelin. Of interest is the presence of the LM1 ganglioside, sialosyl-lactoneotetraosylceramide, as a characteristic component of myelin in the PNS of some species. These differences in lipid composition between CNS and PNS myelin are not, however, as dramatic as the differences in protein composition discussed below. 

In general the sphingolipids are located on the exterior face of a membrane while the phospholipids make up the inner face. This is understandable when we recall that sphingolipids include the gangliosides and cerebrosides whose polar ends contain carbohydrates or complex carbohydrate derivatives. The large number of chiral centers in carbohydrate molecules offer a complex pattern on the surface of the membrane which can impart a large degree of specificity for a particular cell type. The composition and limited fluidity of the bilayer make the entire membrane asymmetric, that is, different on the inner and outer layers or leaflets. 

Prepare a 5 mg/ml liposome construction in 20 mM sodium phosphate, 0.15 M NaCl, pH 7.4, containing, on a molar ratio basis, a mixture of PC cholesterol PG other glycolipids of 8 10 1 2. The other glycolipids that can be incorporated include phosphatidyl inositol, lactosylceramide, galactose cerebroside, or various gangliosides. Other liposome compositions may be used, for example, recipes without cholesterol, as long as a periodate-oxidizable component... 

Our new method of sphingolipid analysis using high performance liquid chromatography allows us to determine not only their quantities but also their homolog compositions in a small amount of tissue. We now feel that less than 1 mg of fresh brain or nerve tissue is sufficient for complete analysis. The application of this new method for analyzing cerebroside and sulfatide-in plaques of brain from a patient with multiple sclerosis has been recently described (15). 

TA8LE 1. Fatty Acid Composition of 8ovine Cerebroside... 

Myelin is modified plasma membrane. Myelin of the PNS resembles that of the CNS with respect to lipid composition. There is an enrichment in such specialized lipids as cerebroside and ethanolamine plasmalogen, and the high content of cholesterol plays an important role in control of membrane fluidity. The protein composition of PNS myelin is, however, distinct from that of CNS myelin. A single protein, P0, accounts for half of all protein of PNS myelin. Of the other proteins present, most are expressed in the CNS as well as the PNS but in quantitatively different amounts. Prominent among these proteins are myelin basic proteins and myelin-associated glycoprotein. 

Stewart RJ, Boggs JM. A carbohydrate-carbohydrate interaction between galactosylceramide-containing liposomes and cerebroside sulfate-containing liposomes Dependence on the glycolipid ce-ramide composition. Biochemistry 1993 32 10666-10674. 

The composition of milkfat is somewhat complex. Although dominated by triglycerides, which constitute some 98% of milkfat (with small amounts of diglycerides, monoglycerides, and free fatty acids), various other lipid classes are also present in measurable amounts. It is estimated that about 500 separate fatty acids have been detected in milk lipids it is probable that additional fatty acids remain to be identified. Of these, about 20 are major components the remainder are minor and occur in small or trace quantities (4, 5). The other components include phospholipids, cerebrosides, and sterols (cholesterol and cholesterol esters). Small amounts of fat-soluble vitamins (mainly A, D, and E), antioxidants (tocopherol), pigments (carotene), and flavor components (lactones, aldehydes, and ketones) are also present. 

Differences in nutritional effects between PLs and TAGs can be caused by several factors not related to their fatty acid composition, such as the presence of a phosphate group and a nitrogen base (mainly chohne) that may interact in several metabolic pathways (82). Moreover, several glycerophospholipid preparations studied can contain other components such as cholesterol, cerebrosides, sphingomyelins also depending on their source, method of isolation, and purification. These components may also affect the nutritional properties. In this chapter, the metabolic fate of constituent fatty acids of PLs and TAGs will be compared. 

In this paper, we have shown that this system can separate molecular species. One example is shown for cerebrosides (Fig. 3B). Human phospholipids and glycolipids have many forms (molecular species) because of the variation in fatty acids or ceramides. Phosphatidylcholine, sphingomyelin, and cerebroside are each reported to consist of more than 100 molecular species.As shown in Fig. 4, it is possible to obtain better resolution by changing the flow rate and the volumes of the fractions. Furthermore, better conditions can be optimized by changing the composition of the solvents to target one hpid, as shown. 

S vennerholm L, Stallberg-Stenhagen S. Changes in the fatty acid composition of cerebrosides and sulfatides of human nervous tissue with age. J Lipid Res 1968 9 215-225. 

Table 10.4. Mean Composition and Cerebroside (GIcCer) Content of 10 Soybean Genotypes Grown Near Ames, lA (Guiterrez et al., 2004a) ...

Moschidis et al. (1984) found small amounts of phosphonohpids in the egg yolk. The comparison of the FA composition of minor components shows that in sphingomyelins the amount of palmitic acid is twice that in the egg yolk lipids, whereas there is almost 40% less oleic acid. Linoleic acid at 30% is found at concentrations about three times higher in lysophosphatidylcholines than in egg yolk hpids, and twice as much as in the PC fraction. At 28%, docosanoic acid (C20 o = behenic acid) is present in considerable amounts in gangliosides, as opposed to lower concentrations of oleic and linoleic acids in comparison with the FA spectrum of egg yolk lipids. Momma et al. (1972) also found a high proportion of approximately 67% hydroxy FA in the cerebrosides. Many of the hydroxy FA have a chiral center. In any case. Momma et al. (1972) determined a relatively high concentration (15.7%) of tetracosanoic acid (C24 o = lignoceric acid), while smaller concentrations of the main FA of the egg yolk lipids were found in the cerebrosides. Table 14.5 shows an overview of the FA spectrum of the minor components. 

Studies on spinal cord myelin lipid composition in mouse model of ALS indicate that levels of lipids, phospholipids, cholesterol, and cerebrosides are decreased compared to wild-type mice (Table 8.4) (Niebroj-Dobos et al., 2007). Although a progressive decrease in proteolipid, DM-20, and Wolfgram proteins occurs in this ALS model, myelin basic proteins I and n are not affected. Electron microscopy indicates massive myelin disorganization (Niebroj-Dobos et al., 2007). Production... 

J. S. O Brien and G. Rouser, The Fatty Acid Composition of Brain Sphingolipids Sphingomyelin, Ceramide, Cerebroside, and Cerebroside Sulfate, J. Lipid Res. 5, 339-342 (1964). 

Their distribution in mammalian tissues is generally similar to that of cerebrosides and their fatty acid and base compositions are also alike. 

Several diseases—Gaucher s, Tay-Sachs, Niemann-Pick, and Fabry s diseases, and the leukodystrophies— are characterized by accumulation of lipoid material in cells. These diseases differ in the composition and site of the lipoid accumulation. Whereas gangliosides accumulate in Tay-Sachs disease, sphingosides are found in Niemann-Pick disease, and cerebrosides in... 

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