Glycolipids lipid

Wanasundara et al. (1999) reported that neutral lipids (acylglycerols and fatty acids) constitute 96% of the total lipid in flaxseed, whereas polar lipids (glycolipids and phospholipids) account for 1.4%. Stenberg et al. (2005) observed similar findings except that less phospholipid was detected. Froment et al. (1999) discussed the effects of cultivar, location, and late harvest on phospholipid content. Neutral lipid fraction of flaxseed meal was 95-98% triacylglycerols (TAG) and thus accounts for the predominant lipid in flaxseed (Oomah et al., 1996). 

Naturally occurring polysaccharides can occur either as individual carbohydrate molecules or in combination with other naturally occurring substances, such as proteins (glycoproteins) and lipids (glycolipids). In all cases the polysaccharide section may have linear or branched chain structures, which often contain the derivatives of both monosaccharides and aminosugars (Figure 1.20). 

Table 4.9. Percentage distribution of neutral and polar lipids (glycolipids and phospholipids) in lipid droplets from 21-day old larvae of Taenia taeniaeformis. (Data from Mills et al., 1983,)...

Of the three molecular constituents of the plasma membrane shown in Figure 13, carbohydrates and proteins are mainly responsible for structural and functional asymmetry of the membrane (89,90,91). Carbohydrates, always found linked to lipids (glycolipids) or proteins... 

Seaweeds Total lipids Neutral lipids Glycolipids Phospholipids... 

The fatty acid composition of hazelnut oil is as follows 78-83% oleic acid, 9-10% linoleic acid, 4—5% palmitic acid, and 2-3% stearic acid as well as other minor fatty acids (Table 3) (1, 22). Parcerisa et al. (23) examined lipid class composition of hazelnut oil, showing that triacylglycerols constituted 98.4% of total lipids, glycolipids comprised 1.4% of total hpids, and trace amounts (<0.2%) of phosphatidylcholine and phosphatidylinositol were also present. Hazelnut oil contains 1.2-1.14 g/kg of phytosterols primarily in the form of p-sitosterol and is a very good source of a-tocopherol (382-472 mg/kg) (1, 22). The main odorant in... 

Glycoconjugates are those hybrid biochemicals which contain carbohydrate chemically bonded to some other component such as peptide (glycopeptide), protein (glycoprotein), lipid (glycolipid), and others. 

The extraction procedme, a modification of Bligh and Dyer [43], wsis performed on lyophilized soil samples fi om the rhizosphere as well as from nonvegetated areas. Extracts were fractionated on silidc acid columns into neutral lipids, glycolipids, and phospholipids. Phospholipid... 

Once non-lipid contaminants have been removed, then it is necessary to purify the phospholipids from other lipids such as neutral lipids, glycolipids and sterols. Cold acetone precipitation is very useful, although it is not completely efficient for mixtures containing high concentrations of neutral lipids and only small amounts of phosphatides (Kates, 1972). Certain plant lipids such as diacyldigalactosyl-glycerol and diacylsulphoquinovosylglycerol may also be precipitated by acetone to some extent. 

Lipids that are solid at ambient temperatures are referred to as fats while those that are liquid are called oils . Two main groups, having significantly different natural functions and structures, can be classified as the neutral lipids (acylglycerides, fatty acids, alcohols, hydrocarbons, waxes) and polar lipids (glycolipids, phospholipids). Neutral lipids generally form part of an energy store, while polar lipids are functional molecules in the structure of membranes. 

Lipids—non-polar lipids, glycolipids, and phospholipids Removal of peroxides— basic, highly active from organic solvents... 

Markello et al. [433] developed a separation on a silica column that gave class separation of nonpolar lipids, glycolipids, phospholipids, and sphingolipids in 60 min. This work was based on the seminal work of Christie [434, 435] and used a silica column and a complex 60-min hexane/THF (99/1)—> chloroform/IPA (1/4)->-IPA/water (1/1) gradient (ELSD). Results were used to assist in the diagnosis of metabolic disease in humans. Retention times for all 13 classes of compounds (fatty acids, PE, PI, PS, PC, ceramides, etc.) were tabulated. The authors noted that retention of CE, TAG and phytol was extremely sensitive to the water level in the mobile phase (i.e., creation of a hydrated and deactivated silica surface). The authon claim that the key here was the use of a saturation column (a column placed in the solvent flow path prior to the injector) and an extended column re-equilibration period after each analysis. 

It was demonstrated that the procedures, as expected, led to differing lipid yields. They differ also, however, in their selectivity with regard to certain lipid classes (neutral lipids, glycolipids, polar lipids). Consequently, only the Bligh and Dryer method delivers maximum extraction for aU lipid classes. ... 

Some preliminary fractionation of lipid samples into simple lipid, glycolipid and phospholipid groups may then be desirable to facilitate their analysis or the isolation of single lipid classes on a small scale. The last objective can be accomplished by high-performance liquid, thin-layer or ion-exchange chromatography. 

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