Glycolipid neutral

Labelled Neutral Glycolipids. Neutral glycolipids were labelled with -galactose. As was seen with the ganglioside, the butyrate affected the neutral glycolipid patterns but the most marked alterations appeared to be due to changes in the lipid moeities. 

The principal material categories discussed in this article are illustrated in Fig. 1. Categories shown are fatty chain acids, salts, alcohols or amines, oils and waxes, phospholipids, glycolipids, neutral lipids, and non-linear chain compounds, such as sterols. 

Table 6.2). Almost all membrane lipids are amphipathic molecules (section 6.5) such as phospholipids or glycolipids neutral lipids such as triacylglycerols have little part in membrane structure. In organisms which make or utilize sterols, these tend to be concentrated in the external surrounding membrane (compare chloroplast or mitochondria with erythrocyte or myelin membranes in Table 6.2). 

Toluidino-2-naphthalene sulfonic acid (TNS reagent) cholesterol [180] phospho- and glycolipids [181] neutral lipids [182]... 

Neutral gangliolipids from Thermoplasma acidophilum were separated by PTLC, and their tentative structures were characterized by the combination of GC, H-NMR, and FAB-mass spectrometries [91]. The lipophilic portion of the neutral glycolipid was composed of caldarchaeol (dibiphytanyl-diglycerol tetraether), and the sugar moieties of the glycolipids were composed of glucose. 

It is commonly known that lipids, carbohydrates, and glycolipids are present in the Golgi apparatus (27). The determination of the components that react with the ZIO mixture was carried out by removing each component from tissues before incubation in the ZIO mixture. After lipid extraction by acetone (14), chloroform-methanol (15), or propylene oxide (27), no osmium-zinc precipitates could be detected in structures that normally reacted with ZIO. Blumcke et al. (15) summarized the nature of the lipids that react with the ZIO mixture as follows lipids and lipoproteins of cell membranes, neutral fat droplets (41), and lipid globules of type II pneumocytes and alveolar macrophages were, however, not as electron dense as the normally reactive lamellae containing highly unsaturated fatty acids. 

Many solvent combinations have been described for two-dimensional separation and, in general, if an alkaline or neutral solvent is chosen for the first dimension then the second solvent should be acidic. Also it may be useful for one solvent to contain acetone, which will enhance the movement of glycolipids relative to the phosphoglycerides. Acetic acid should not be used in the first solvent, because it is difficult to remove completely and affects the quality of the separation in the second dimension. Difficulties are also encountered in the removal of butanol, which interferes with the charring process often used for the location of the spots. 

Kannan and coworkers also used M hydrochloric acid at 100° for the hydrolysis of neutral glycolipids 6 h was found sufficient for hydrolysis of galactolipids, but 12 h was required for complete cleavage of the glucose-ceramide bond. The use of standard ceramide mono- and di-hexosides subjected to hydrolysis for 12 h gave monosaccharide recoveries of >94%... 

Complex lipids, such as neutral fats (triacyl-glycerols), phospholipids, and glycolipids, are synthesized via common reaction pathways. Most of the enzymes involved are associated with the membranes of the smooth endoplasmic reticulum. 

When the individual proportions of lipids in membranes are examined more closely (right part of the illustration), typical patterns for particular cells and tissues are also found. The illustration shows the diversity of the membrane lipids and their approximate quantitative composition. Phospholipids are predominant in membrane lipids in comparison with glycolipids and cholesterol. Triacyl-glycerols (neutral fats) are not found in membranes. 

In the spermatozoa of the sea urchin Anthocidaris crassipina, nine sialoglycolipids were found, two of which were isolated and their structures established from the results of acid hydrolysis, methylation, and periodate oxidation.139 The major component of the glycolipid mixture is a disialo-glycolipid, NeuAc-(2- 8)-NeuAc-(2- 6)-Glc-Cer. The least-polar, minor component has the structure of a monosialoglycolipid, NeuAc-(2 - 6)-Glc-Cer. In these compounds, glucose is again the only neutral monosaccharide, and the sialic acid is attached to it at 0-6. 

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