Tissue components, extraction

Because of their very complex chemical structures and heterogeneity, melanins are difficult to extract, separate, and characterize from tissues. Eumelanins are insoluble in water and organic solvents. They can be extracted from tissues with strong chemicals that are capable of removing lipids, proteins, and other tissue components but also lead to the formation of degradation products. Enzymatic procedures were developed for the isolation of eumelanins from mammalian hair and irises. The first step is sequential digestion with protease, proteinase K, and papaine in the presence... 

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. 

A similar in vitro system used [%] A-9-DMHP mass spectra of incubation extracts were silylated and subjected to gas chromato-graphy/mass spectrometry. Strong evidence was accumulated that the major metabolite was U-hydroxy-DMHP. Overall recovery of the metabolite was only A.7% this low yield was insufficient for confirmatory analyses by other methods, such as nuclear magnetic resonance. The low recovery indicated to the investigators that DMHP and its metabolites are much more strongly bound to tissue components than are THC and its metabolites. Sixteen hours after injection of [ HjDMHP into mice, their brains were extracted. Gas chromatography of the extracts indicated retention times identical with those of synthetic 11-hydroxy-DMHP, which accounted for 90% of the radioactivity two... 

In addition, residues of corticosteroids can be cleaned up through application of a three-phase liquid-liquid partition system consisting of acetonitrile, hexane, and dichloromethane. Since its inception, this procedure has been used successfully to perform a fast, crude fractionation of tissue components and drugs extracted from tissue homogenates into the aqueous acetonitrile supernatant. Non-... 

Physical Properties. All of the cellulase (CMCase) activity which develops in auxin-treated pea apices dissolves in salt solutions (e.g., phosphate buffer, 20mM, pH 6.2, containing 1M NaCl). Gel chromatography of such extracts indicates the presence of two cellulase components with similar levels of activity and elution volumes corresponding to molecular weights of about 20,000 and 70,000 (Figure 1). If the tissue is extracted with buffer alone, only the smaller cellulase dissolves (referred to as buffer-soluble or BS cellulase). The larger buffer-insoluble (BI) cellulase can then be extracted from the residue by salt solutions. This simple extraction procedure effectively separates the two cellulases, and can be used as an initial step for their estimation or purification. 

To summarize the present position concerning the determination of elastin in tissues it appears that procedures based on the successive removal of all other tissue components, by the use of suitable extractants, are satisfactory provided conditions are carefully chosen to secure adequate purification of the elastic residue without any loss of elastin by partial hydrolysis and dissolution. When muscle or other cells are abundant in the tissue or the content of mucopoly.saccharide and mucoprotein... 

Limited data were located regarding methods for detecting the hydrocarbon components of gasoline in biota (bivalve mollusks) (Dimock et al. 1980). The methods used were GC (detector not reported) and GC/MS. Sample preparation included tissue digestion, extraction and clean-up, and solvent exchange to hexane. Recovery was poor (-60%). Sensitivity and precision were not reported. 

The true detoxification products as a rule appear in the urine, while the reactive intermediate toxic products remain in the body, tightly bound to tissue components, and thus chemically sequestered in the tissues. From the toxicological point of view therefore, it is not the percentage of the pharmacon and its metabolites recovered from urine, feces, and from the carcass by extraction that is most important in balance studies it is in fact the fraction of the... 

Glycosaminoglycans are solubilized from stromal or other tissues by extracting the source tissue with dilute acid or alkali. Hyaluronan is electrostatically bound to specific proteins called hyaladherins, which possess a structural domain of -100 amino acids termed a link module. Other glycosaminoglycans are O-linked to serine and threonine residues of polypeptides and these bonds hydrolyze before the rest of the polysaccharide. The protein moiety precipitates when trichloroacetic acid or ammonium sulfate is added to the cooled mixture. The composition of the GAGs (including hyaluronan) was identified by chromatographic separation of the purified polysaccharides, followed by their hydrolysis in boiling 1.0 M HC1 for 2 1 h and identification of the individual monosaccharide components. 

Upon collection, tissues are typically frozen in liquid nitrogen and then homogenized by grinding the frozen sample to a fine powder. Extraction of tissue components is most commonly performed using LLE. Polar compounds are extracted with polar solvents including methanol, ethanol, isopropanol, acetonitrile, water, or polar solvent mixtures, while nonpolar compounds are extracted with ethyl acetate or chloroform. Such an LLE yields two fractions (polar and nonpolar) that can be analyzed separately [76,95,96],... 

This is a generic formula to incorporate proteins, tissue components, or enzyme extracts (in powder form). 

An additional complication in studying the polysaccharides of the cell wall is that they can form compounds/complexes with noncarbohydrate compounds such as lignin, polyphenolics that are quite distinct from lignin, and proteins. Such complexes have been isolated from a range of tissues by extraction with a variety of reagents and by suitable fractionation (Selvendran, 1985). These studies suggest that in some of the complexes the polysaccharides and noncarbohydrate components are bound together by covalent links. Attention will also be drawn to some of the recent developments in this area. 

Recently, our laboratory has utilized an improved extraction procedure for NGF (Zettler et al., 1995) to examine the effect of surgical denervation on its concentration within the mesenteric artery. The high levels of NGF present were reduced by denervation to approximately 20% of control levels. By assaying NGF within the adventitia and media separately, it was possible to demonstrate that the loss of NGF was associated only with the loss of nerve fibres within the adventitia. Furthermore, the discrepancy with the studies described above could be explained by the ability of the new extraction procedure to free large amounts of NGF bound to tissue components (such as trkA receptors) prior to assay (Liu, Reid, Bridges and Rush, unpublished observations). 

Phospholipid contents are very similar (about 1 to 2% dry matter) in microbial, plant, and animal tissues. If the content of neutral lipids is low, phospholipids may account for 20 to 40% of lipid extracts (e.g., in marine invertebrates). In egg yolk, 23% of the total lipids are phospholipids and other polar lipids (Kuksis, 1985). On the contfary, in adipose tissue or in oilseeds, the content of phospholipids is between 1 and 3% of total lipids. In oilseeds rich in oil (such as in rapeseed), it is lower than in oilseed with lower oil content (such as soybeans) when the results are expressed in % oil content, but much the same if the content is expressed in terms of total dry matter of the oilseed. Phospholipids are mainly extracted by nonpolar solvents, together with other lipids, and are obtained in the crude oil. However, in the original material, phospholipids are primarily bound to proteins (e.g., in membranes) or may be bound to other tissue components for example, phospholipids interact with chlorophyll pigments, where they may form complexes between the magnesium ion of the chlorophyll molecule and the phospho group of the phospholipids. 

The nucleotide profiles of Figs. 1-1 and 1-2 show that cells and tissues contain complex mixtures of nucleotides. The principal components of such mixtures can be isolated and determined using current methods of column and thin-layer chromatography with anion exchange media. However, a crucial step prior to analysis is the extraction of nucleotides from cells. With some tissues, the extraction procedure has a profound influence on the analytical result and special precautions must be taken if the result is to truly represent the nucleotide composition of living cells. 

Samples are extracted prior to injection onto the column. This serves two major purposes (a) solid tissue components are removed to prevent... 

A number of zoopolysaccharides have been isolated in purified condition and the structures partially established. Many of these are bound with other tissue components in the natural condition. They are isolated from the macerated tissues or the secretions by extraction with alkalies or salts (especially calcium chloride). Mucins and many mucoids are precipitated by weak acids, and their polysaccharide components are subsequently recovered. If dissociable, proteins may be removed by precipitation with amyl alcohol - chloroform (Sevag) or formaldehyde (Masamime). Peptic or tryptic digestion may remove these and covalently bound proteins. Colorimetric, chromatographic, and isolation methods have been used for the identification of the component sugars (, 14, 15-16h), (See also imder Glucosamine, Chapter VIII, Uronic acids. Chapter VI and part I, Chapter XII.)... 

Polar linkages seem to be the principal basis of association of the components of ground substance with the insoluble tissue components, for most of the dissolved components of ground substances and some of the fibrous elements are readily extracted by salt solutions or weak alkalies. Some type of interaction seems very probable, for extracted soluble collagen can be reversibly precipitated into several types of characteristic fibrils, the forms of which depend upon the precipitating conditions and upon the presence... 

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