Lipid components

The yolk is separated from the white by the vitelline membrane, and is made up of layers that can be seen upon careful examination. Egg yolk is a complex mixture of water, Hpids, and proteias. Lipid components iaclude glycerides, 66.2% phosphoUpids, 29.6% and cholesterol [57-88-5] 4.2%. The phosphohpids consist of 73% lecithin [8002 3-5] 15% cephahn [3681-36-7], and 12% other phosphohpids. Of the fatty acids, 33% are saturated and 67% unsaturated, including 42% oleic acid [112-80-1] and 7% linoleic acid [60-33-3]. Fatty acids can be changed by modifying fatty acids ia the laying feed (see... 

Hydrated bilayers containing one or more lipid components are commonly employed as models for biological membranes. These model systems exhibit a multiplicity of structural phases that are not observed in biological membranes. In the state that is analogous to fluid biological membranes, the liquid crystal or La bilayer phase present above the main bilayer phase transition temperature, Ta, the lipid hydrocarbon chains are conforma-tionally disordered and fluid ( melted ), and the lipids diffuse in the plane of the bilayer. At temperatures well below Ta, hydrated bilayers exist in the gel, or Lp, state in which the mostly all-trans chains are collectively tilted and pack in a regular two-dimensional... 

Figure 5 Electron density distributions along the bilayer normal from an MD simulation of a fully hydrated liquid crystalline phase DPPC bilayer. (a) Total, lipid, and water contributions (b) contributions of lipid components in the interfacial region.

Figure 10.2. Schematic diagram showing how restricted conversion of fatty acids to amino acids influences the fractionation between collagen and CO3 of bone apatite LI = lipid component, PR = protein, T = total isotopic composition AP = COj component of apatite, a) Herbivorous diet (Cj plants only) b) Carnivorous diet, assuming rj = 1 (no barrier to fatty acid conversion to AAs) c) Carnivorous diet, assuming ri < 1 note that carbonate-collagen fractionation is smaller.

The data sets presented by Ambrose and Norr (1993) and Tiezsen and Fagre (1993) record analyses of rodents fed on diets in whose dietary components have been analyzed. Thus D and F are given for the diets, (generally for the protein, carbohydrate and lipid components sometimes in more detail), and have been varied so as to relate to the corresponding change in B. Measurements were made on animals thought to have reached an overall steady state. 

Petrovskii, A., Loiko, N., Nikolaev, Yu., Kozlova, A., El -Registan, G., Deryabin, D., Mikhailenko, N., Kobzeva, T., Kanaev, P., Krupyanskii, Yu. Regulation of the function activity of lysozyme by alkylhydroxybenzenes. Microbiology, Vol.78, No.2, (March 2009), pp. 144-153, ISSN 1350-0872 Reusch, R., Sadoff, H. Novel lipid components of the Azotobacter vinelandii cyst membrane. 

A consistent pericardial edema in chickens gave rise to the term chick edema disease (chick edema factor) (I). Two known outbreaks of the disease in the broiler industry resulted in a great loss of chickens. A lipid residue from the manufacturing fatty acids, being used as a feed ingredient, was a principal source of the toxic substance. Contamination of the lipid component with polychlorodibenzo-p-dioxins was attributed as the causal agent. 

When liposomes are prepared from a molecular mixture of lipid components it is important that all lipids be homogeneously dissolved in an organic solvent in order to obteiin bilayers with evenly distributed lipids after hydration. For example, the solubilities of phosphatidylcholine and cholesterol in chloroform are similar their solubility in benzene differs. Upon removal of benzene from the lipid solution an inhomogeneous lipid film is formed on the glass wall and... 

Other potential adverse effects resulting from liposome administration which need to be studied are undesired complement activation (Cunningham et al., 1979), blood clotting, and pharmacological effects of the lipid components as well as physical obstruction of small capillaries by large particles. 

For a number of liposome preparations—both injectables and locally administered products—the therapeutic advantages over existing formulations have been proven in animal models clinical trials with liposome preparations are now under way. So far, clinical studies showed no significant toxic effects which could be ascribed to the lipid components of the liposomes used. 

Lipoprotein Source Diameter (nm) Density (g/mL) Composition Main Lipid Components ApolipoprotGins... 

The cell walls of mycobacteria contain three structures peptidoglycan, an arabinogalactan polysaccharide and long chain hydroxy fatty acids (mycolic acids) which are all covalently linked. Additional non-covalently attached lipid components found in the wall include glycolipids, various phospholipids and waxes. The lipid-rich nature of the mycobacterial wall is responsible for the characteristic acid-fastness on staining and serves as a penetration barrier to many antibiotics. Isoniazid and ethambutol have long been known as specific antimycobacterial agents but their mechanisms of action have only recently become more clearly understood. 

The amoimt of lipid applied to the plate varies depending on the ease of separation of individual lipid components in the sample. Usually 25 to 50 mg of the neutral lipid sample can be applied to a 20 X 20 cm preparative plate with the silica gel G layer thickness of 0.5 mm, whereas only about 4 mg of phospholipids can be applied on these plates. 

PTLC was also used for the separation of lipid components in pathogenic bacteria. Mycobacterium avium has a requirement for fatty acids, which can be fulfilled by palmitic or oleic acid, and these fatty acids are then incorporated into triagylglycerols [80]. PTLC was used for the separation of fatty acids and triacylglycerols in the extracts of these bacterial cells to study the lipid classes in the bacterial cells cultured under different growth conditions. 

In addition, data obtained from infrared, thermal, and fluorescence spectroscopic studies of the outermost layer of skin, stratum corneum (SC), and its components imply enhancer-improved permeation of solutes through the SC is associated with alterations involving the hydrocarbon chains of the SC lipid components. Data obtained from electron microscopy and x-ray diffraction reveals that the disordering of the lamellar packing is also an important mechanism for increased permeation of drugs induced by penetration enhancers (for a recent review, see Ref. 206). 

The double bonds were reduced to the give the saturated compounds, so the doublebond configuration was not an immediate issue. It appears, however, that the -double bonds are formed. The debenzylated derivatives of propan-1,2,3-triol occur as lipid components in various prokaryotes (archaebacteria) that grow under extreme thermal conditions. 

The determination of partition coefficients using liposomes as a lipid phase require that the sample be equilibrated with a suspension of liposomes, followed by a separation procedure, before the sample is quantitated in the fraction free of the lipid component. 

Different tissues have different lipid compositions. The most common lipid components of membranes are PC and PE. Lipid extracts from brain and lung are also rich in PS heart tissue is rich in PG, and liver is rich in PI [567]. Human blood cells, as ghost erythrocytes (with cytoplasm contents removed), are often used as membrane models. These have different compositions between the inner and outer leaflets of the bilayer membrane. Phospholipids account for 46% of the outer leaflet membrane constituents, with PC and Sph about equal in amount. The inner leaflet is richer in phospholipids (55%), with the mix 19% PE, 12% PS, 7% PC and 5% Sph [567],... 

Biological membranes consist of lipids, proteins and also sugars, sometimes mutually bonded in the form of lipoproteins, glycolipids and glycoproteins. They are highly hydrated—water forms up to 25 per cent of the dry weight of the membrane. The content of the various protein and lipid components varies with the type of biological membrane. Thus, in... 

The lipid component consists primarily of phospholipids and cholesterol. The most important group of phospholipids are phosphoglycerides, based on phosphatidic acid (where X = H), with the formula... 

The formation of lipid components in an aqueous phase at temperatures from 370 to 620 K was studied by Rushdie and Simoneit (2001), who heated aqueous solutions of oxalic acid in a steel vessel for 2 days the yield of oxidized compounds reached a maximum (5.5% based on oxalic acid) between 420 and 520 K. A broad spectrum of compounds was obtained, from n-alkanes to the corresponding alcohols, aldehydes and ketones. At higher temperatures, i.e., above 520-570 K, cracking reactions competed with the synthetic reactions. 

Hydrophobically modified HA derivatives,91 obtained through the partial esterification of the HA carboxyl groups with methylprednisolone (45% in HYCp45 and 60% in HYCp60),92 have been deeply studied 93 A key point prior to any in vivo study of the biomaterial is the assessment of the so-called "stealth character" of the species itself. Such characteristic corresponds to be invisible towards the immune system, so that colloids are not recognized as foreign objects by body fluid components, as plasma proteins fibrinogen, BSA and lipidic components.94,95... 

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