Sphingolipid types

Fig. 14.—Schematic Representation of the Fragmentation Observed in the Positive F.a.b.-Mass Spectrum of a Permethylated Ganglioside Isolated from Granulocytes. [Other glyco-sphingolipids fragment in a similar way. Major cleavages are shown with solid lines, and minor cleavages with dotted lines. The masses of ions resulting from cleavages (a), (b), and (c) define the type of sphingosine and the type of fatty acid. In this example, (a) is 548, (b) is [M + H] minus 238, and (c) is [M + H] minus 533.]...

Niemann-Pick disease C type 2 Gmj activator protein deficiency Sphingolipid activator protein deficiency... 

Lehtonen, J.Y.A., Horiuchi, M., Daviet, L., AMshita, M. and Dzau, V.J., 1999, Activation of the de novo biosynthesis of sphingolipids mediates angiotensin 11 type 2 receptor-induced apoptosis. J. Biol. Chem. 274 16901-16906. 

Sonicate the test tubes in a bath-type sonicator until they appear evenly dispersed incubate overnight at 48°C in a heating block. This heating step can often be shortened, but it is conventional in the extraction of sphingolipids because they have high phase transition temperatures. 

A. The three major types of amphipathic lipids found in membranes are the gly-cerophospholipids (also called phosphoglycerides), the sphingolipids, and cholesterol. 

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. 

The white matter is a covering for the nerve fiber known as the myelin sheath. Myelin is a sphingolipid produced by oligodendrocytes (Schwann cells). It acts as a special type of insulation which allows for a much more rapid transmission of the nerve signal. The myelin cover is interrupted periodically. This "bare" area is called a node of Ranvier. It is very important to rapid nerve conduction. See Figure 21. 

O. Macheleidt, T. Kolter, K. Sandhoff, Sphingolipid activator deficiencies and Niemann-Pick Type C,... 

Fatty acyl residues (R) commonly found in membrane lipids are summarized in Table 1.2 [2]. Generally, four lipid structures are mainly found in eucaryotic cells phospholipids, sphingolipids, glycolipids, and sterols [2]. The various organs differ in their phospholipid composition (Table 1.3). As an example, the composition of the liver cell membrane is given [2].There is also a considerable difference in the proportion of phospholipids in different cell types and in different species. Figure 1.2... 

Ethanol and methanol have been used to swell other types of keratinized protein without loss of the a-helieal structure in the presence or after removal of the alcohols (46). Polar lipids such as the ceramides or sphingolipids are soluble in methanol (47). Therefore, extensive extraction periods in methanol could have provided sufficient time to swell the keratinized protein and allow the highly polar lipids entrapped within the protein fibrils to diffuse from the stratum corneum sheet. The resultant protein residue sheets retained the a-keratin conformation throughout the extensive extraction process. 

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