Lipids polar animal

Extraction of Non-Polar Animal Lipids according to Bloor [15]... 

Polar Animal Lipids. The experimental conditions quoted in the first articles [70, 210] on thin-layer chromatographic separation of phospholipids in animal and human organs, have proved satisfactory. They have needed modification, however, in a few special problems [67, 163, 188, 200]. The range of application of TLC has been appreciably extended recently by introduction of the two-dimensional technique [159a, 177, 186] (see Fig. 151). 

Phospholipids are found widely in both plant and animal tissues and make up approximately 50% to 60% of cell membranes. Because they are like soaps in having a long, nonpolar hydrocarbon tail bound to a polar ionic head, phospholipids in the cell membrane organize into a lipid bilayer about 5.0 nm (50 A) thick. As shown in Figure 27.2, the nonpolar tails aggregate in the center of the bilayer in much the same way that soap tails aggregate in the center of a micelle. This bilayer serves as an effective barrier to the passage of water, ions, and other components into and out of cells. 

Bufotenine has been found to be behaviorally inactive, or only weakly active, in most animal studies, although at 15 mg/kg, it did produce the head-twitch resonse in mice (43). It was also behaviorally active in experiments in which the blood-brain barrier was bypassed (78). Acylation of the polar hydroxy group of bufotenine increases its lipid solubility (65,74) and apparently enhances its ability to cross the blood-brain barrier (64). For example, O-acetylbufotenine (5-acetoxy-N,N-dimethyltryptamine 54) disrupted conditioned avoidance behavior in rodents (65) and produced tremorigenic activity similar to that elicited by DMT (37) or 5-OMeDMT (59) when administered to mice (64). In this latter study, a comparison of brain levels of bufotenine after administration of O-acetylbufotenine with those of DMT and 5-OMeDMT revealed bufotenine to be the most active of the three agents, based on brain concentration. The pivaloyl ester of bufotenine also appears to possess behavioral activity, since stimulus generalization was observed when this agent was administered to animals trained to discriminate 5-OMeDMT from saline (74). 

When plant or animal tissues are extracted with nonpolar solvents, a portion of the material dissolves. The components of this soluble fraction are called lipids and include fatty acids, triacylglycerols, waxes, terpenes, postagladins, and steroids. The insoluble portion contains the more polar plant components including carbohydrates, lignin, proteins, and nucleic acids. 

Spermine has been found to enhance the transfection efficiency of DNA-cationic liposome complexes in cell culture and in animal studies this biogenic polyamine at high concentrations caused liposome fusion most likely promoted by the simultaneous interaction of one molecule of spermine (four positively charged amino groups) with the polar head groups of two or more molecules of lipids. At low concentrations (0.03-0.1 mM) it promoted anchorage of the liposome-DNA complex to the surface of cells and enhanced significantly transfection efficiency. 

The procedure of isolating the glycosphingolipids is based on their physicochemical properties. The presence of the lipophilic, lipid moiety results in their solubility in such typical solvents for lipids as chloroform-methanol. On the other hand, the presence of the carbohydrate moiety imparts to them hydrophilic properties that increase with increase in the length of the carbohydrate chain and with the presence of such polar monosaccharides as sialic acid. This very property makes it possible to subdivide the glycolipids further, according to their polarity. In principle, the isolation of glycosphingolipids from marine animals does not differ from their isolation from other sources, a procedure comprehensively elucidated in a number of reviews.80 88... 

In brief, the isolation scheme is as follows. First, the lipids are all extracted from the animal tissue, generally by using chloroform-methanol or chloroform-methanol-water. An increase in the polarity of the extracting system makes it possible to extract more fully the polar glycosphingolipids, especially polysialoglycolipids, but may, however, lead to contamination... 

The extraction procedure used to isolate lipids from biological tissue depends on the class of lipid desired and the nature of the biological source (animal tissue, plant leaf, plant seed, bacteria, cell membranes, etc.). Because lipids are generally less polar than other cell constituents, they may be selectively extracted with the use of organic solvents. Early studies of lipids used ether, acetone, hexane, and other organic solvents for extraction however, these solvents extract only lipids bound in a nonpolar or hydrophobic manner. In the 1950s, Folch s group reported the use of chloroform and methanol (2 1) in... 

Chromarod FID peaks of sterols, diglycerides, monoglycerides, and polar lipids are narrower and sharper than peaks of triglycerides and free fatty acids when analyzed using either method described in this unit (see Basic Protocol and Alternate Protocol). Hydrogenation of total lipids (see Support Protocol) results in much sharper and narrower peaks, which in turn substantially improves the resolution between lipid classes. The accuracy and precision in quantitating lipid classes of vegetable oils and animal fats are expected to be better than those from marine lipids. 

However, NP-HPLC has been criticized because of the apparent similarity in polarity between many OPPs, and the lipids of both animal and plant origin precluded the development of... 

Although many measurements of potentials have been made with membranes obtained from animals, one needs simplification3 if one is to understand the function of various entities of a cell. The most common model system to act as a simplified biological membrane is the bilayer lipid membrane (BLM), first prepared by Mueller in 1962. It consists of two lipid molecules tail to tail (Fig. 14.8) with the polar groups... 

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