Lipid phospholipids

The topic of lipoproteins is the most complicated issue presented in this chapter. Lipoproteins are complexes of specific proteins and lipids. Each lipoprotein contains different proportions of various lipids. The constant component of any one type of lipoprotein is the protein hence, the structure or function is described by first naming the protein. Lipoproteins are synthesized primarily in the intestines and liver and are secreted into the plasma, where their function is to transport various Lipids. Lipoproteins are water soluble because of their outside coat of proteins and the hydrophilic phosphate groups of their phospholipids. This water solubility enables lipoproteins to transport the triglycerides and cholesteryl esters that reside within their cores. An understanding of lipoproteins is useful to individuals interested in energy metabolism and essential to those concerned with cardiovascular disease. 

When speaking about health, the terms LDL and LDL-cholesterol mean the same thing, and the terms HDL and HDL-cholesterol mean the same thing. But to the biochemist, the terms LDL and HDL mean a specific combination of proteins, cholesteryl esters, triglycerides, and phospholipid — and not just the cholesterol component. 

The major components of cell membranes are proteins, cholesterol, lipids with a glycerol backbone, and lipids with a sphingosine backbone. The glycerol-based lipids are phospholipids with fatty acids esterified at the 1 and 2 positions of the glycerol, and a molecule of phosphocholine, phosphoethanolamine. 

TABLE 6 1 Phospholipid Composition of One Type of Plasma Membrane 

PhosphattdykhoHne (PC) and phosphatidylethanolamine (PE) are the major phospholipids of cell membranes. Table 6.1 lists the amount of lipid in cell membranes expressed as micrograms of lipid per milligram of membrane-bound protein. The membranes were isolated from cells of adipose tissue from rats that had been raised on a diet containing sunflower oil (100 g oil/kg diet) as the source of lipids. The diet was essentially free of cholesterol and phospholipids because plants do not contain cholesterol and the phospholipids of vegetable oils are removed during the refining process. 

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Using PTLC six major fractions of lipids (phospholipids, free sterols, free fatty acids, triacylglycerols, methyl esters, and sterol esters) were separated from the skin lipids of chicken to smdy the penetration responses of Schistosoma cercaria and Austrobilharzia variglandis [79a]. To determine the structure of nontoxic lipids in lipopolysaccharides of Salmonella typhimurium, monophosphoryl lipids were separated from these lipids using PTLC. The separated fractions were used in FAB-MS to determine [3-hydroxymyristic acid, lauric acid, and 3-hydroxymyristic acids [79b]. 

Haider SS, Hasan M, Islam F. 1980. Effect of air pollutant hydrogen sulfide on the levels of total lipids, phospholipids cholesterol in different regions of the guinea pig brain. Indian J Exp Biol 18 418-420. 

FIGURE 10.12 The mole ratio of carotenoid/phospholipid and carotenoid/total lipid (phospholipid + cholesterol) in raft domain (detergent-resistant membrane, DRM) and bulk domain (detergent-soluble membrane, DSM) isolated from membranes made of raft-forming mixture (equimolar ternary mixture of dioleoyl-PC (DOPC)/sphingomyelin/cholesterol) with 1 mol% lutein (LUT), zeaxanthin (ZEA), P-cryptoxanthin (P-CXT), or P-carotene (P-CAR). 

Compound lipids (phospholipids, sphingolipids, glycolipids, and cholesterol and its esters) that make part of the biomembrane are subject to a less active renew-al as compared with triacylglycerides. Their renewal is associated either with the restoration of an impaired portion of the membrane, or with the replacement of a defective molecule by a new one. 

Mosquitofish, Gambusia affinis, adults, muscle 18,000 After 24 h, Zn increased from 82 to 134 pg/kg FW significant increases in glycogen, total lipids, phospholipids, and cholesterol decreases in RNAand proteins 59... 

Phosphate ions are constituent parts of two universally found biopolymers, DNA and RNA. Phosphate ion is found in membrane lipids (phospholipids) and associated with the metabolism of many small molecules. The binding of dioxygen by hemoglobin is regulated by local concentrations of H+ (known as the Bohr effect), CO2 concentration, and organic phosphates such as diphos-phoglycerate (DPG), whose structure is shown in Figure 5.1. ... 

Stress For example, mitochondrial inhibitor, oxidant, substance accumulation (e.g., lipid, phospholipid, fluid)... 

Glycolipid incorporated liposomes have found extensive use as sensors for the detection of Escherichia coli bacteria. Liposomes prepared using a diacetylene and a glucosyl lipid underwent a chromatic transition upon the addition of E. coli (Ma et al. 1998). The chromatic transition is sensitive to the diyne and glycolipid stmc-ture (Ma et al. 2000). An optimized vesicle assembly, consisting of a maltotriosyl lipid, phospholipid, and diyne, detected E. coli at a concentration of 2x10 cells/mL... 

Dose-dependent (up to 5 mg/L) accumulations in blood and ovary, decrease in gonadosomatic index and number of ova No deaths. Reduction in liver and ovary total lipids, phospholipids, and cholesterol increases in free fatty acid levels and lipase activity LC50... 

The vesicles were shown to be rich in lipids with at laest 1.5 times more total lipid, phospholipid, cholesterol and glycolipid per unit protein than in whole chondrocytes. The ratio of cholesterol to PL was 1.7 times greater in vesicles than in chondrocytes and vesicles which contained twice the cellular amount of phosphatidyl serine and sphingomyelin102, 46S) and which are depleted in phosphatidyl choline. It is of note that the principal PL in vesicles was phosphatidyl serine which has been shown to have a strong affinity for calcium ions, especially in the presence of phosphate96). 

Definition and example of a glycerophospho-lipid Phospholipids that contain glycerol are called glycerophospholipids or phosphoglyc-erides. All contain phosphatidic acid, the simplest glycerophospholipid. When an alcohol, such as choline, is esterified to phosphatidic acid, the product is phosphatidylcholine. 

Modern LSD detectors yield good results even under gradient elution. No disturbance is observed when solvent composition changes. Organic solvents (acetone, propanol, chloroform) can be used in the mobile phase. In reversed-phase mode, water content up to 25% and small amounts of buffers are not a problem. Typical applications are lipids, phospholipids, sugars, and vitamins. 

Fig. 18.3. Raman spectral analysis of foetal osteoblast (FOB) differentiation. Unsupervised PCA of FOB cells cultured for 3 days in bioactive glass (BG) conditioned media (triangle) or control media (circle) (a). BG-treated cells formed a distinct cluster separate from control cells after 3 days culture. Least square (LS) analysis (which decomposes the cell spectra into the linear combination of Raman spectra obtained from the pure chemical constituents of the cell, e.g. nucleic acid, proteins, lipids, phospholipids and carbohydrates) of the relative RNA concentration of FOBs cultured for 1, 3 and 14 days in culture media (black) or BG condition media (grey), revealed a significantly reduced relative RNA concentration in FOBs culture in BG-conditioned media (b). FOBs cultured in BG-conditioned media appeared to accelerate FOB differentiation into mature adult osteoblast phenotypes (parallel gene and protein expression experiments confirmed this). Significant difference to control (p <0.05) [38]...

Another finding that reinforces the probable germ cell location of the SGG was made by Suzuki et al. (30). These workers fed adult rats a diet deficient in vitamin A for 46 days. This resulted in a decline of SGG to 13% of its level in the testes of appropriate control animals. Total lipid, phospholipid and DNA (expressed appropriately) were only slightly reduced. Histologic examination showed that the testes were aspermatogenic. Vitamin A is obviously necessary for the maintenance of germ cell maturation it would be of great interest to determine if it plays any specific role in the biosynthesis of SGG. 

It was demonstrated previously that allicin extracted from garlic had a lipid-lowering effect on long-term feeding to healthy rats. These studies reported a significant decrease in total serum lipids, phospholipids, and cholesterol in the animals fed allicin compared to control animals. 

Low molar mass species, such as lipids, phospholipids (lecithin), mono- and diglycerides1, sorbitan monostearate, polyoxyethylenesorbitan monostearate. 

Tissue blood PCs indicate the relative affinity of compounds for the various tissues of the body compared to blood. The values are determined by the relative lipophilic/hydrophilic nature of the compound and relative affinity for the macromolecules found in tissue and blood. Each individual tissue will make up a specific balance of water, neutral lipid, phospholipid, and protein. Partitioning therefore is determined by the relative affinity of the compound for the specific tissue constituents. 

There is abundant evidence to support the concept that the outer layer of plasma lipoproteins is a monolayer of polar lipids (phospholipids, mainly phosphatidylcholine, and cholesterol) and apolipoproteins with the hydrophilic aspect of the apolipoproteins and the polar head groups of phospholipids on the surface. The evidence has been reviewed by others [e.g., (S24)] and will not further be examined here. Nuclear magnetic resonance studies on HDL have shown that about 40% of unesterified cholesterol molecules are in the lipoprotein core, and 60% are associated with phospholipid molecules in the surface. Neither surface nor core is saturated with cholesterol (L20). Presumably, unesterified cholesterol is also found in the core of other lipoproteins. 

Substances commonly found in starch granules are amylopectin, amylose, molecules intermediate between amylose and amylopectin, lipid (including phospholipids and free fatty acids), phosphate monoester and proteins/enzymes. The contents and the structures of amylopectin and amylose play major roles in the functional properties of starch. However, lipids, phospholipids and phosphate monoester groups have significant effects on starch functional properties, even though they are minor constituents. 

Preparation of DHPC stock solution. Prepare a stock solution of the detergent in water (or D20 if desired for NMR purposes). A 1M solution of DHPC is convenient for preparing bicelles with a total lipid (phospholipids + detergent) concentration of 300 mM (see Note 6). 

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