Mucopolysaccharides fractionation

Keratan sulfate constitutes approximately half the total mucopolysaccharide fraction of bovine cornea, where it was isolated originally by Meyer et al. (M16). It occurs fairly widely in animal connective tissues, and its presence has been reported in nucleus pulposus (G2), aorta (B17), and costal cartilage (M20). Unlike the acid mucopolysaccharides described previously, keratan sulfate contains no uronic acid residue but is comprised of V-acetyl-n-glucosamine, D-galactose, and sulfate, in equimolar ratio. The small amount of L-fucose detected in acidic... 

One of the manifestations of generalized or localized pretibial myxedema is a pronounced edema of the corium, with accumulation of mucinous material in the edema fluid. Both hyaluronic acid and a sulfated mucopolysaccharide fraction were isolated in increased quantity from the affected area of the skin of a patient with localized pretibial myxedema (Wl). Following this observation, the relationship between the functional status of the thyroid gland and the mucopolysaccharides of skin has been discussed in numerous publications. Analysis of the acid mucopolysaccharides of human skin has revealed the presence of dermatan sulfate, hyaluronic acid, and a small amount of chondroitin 4- or 6-sulfate (L9). 

It is known, that uric acid seems to be important in the formation of calcium oxalate stones. Robertson has shown in his model of stone formation the decrease of urinary inhibitory activity with high concentrations of uric acid. Thus the effective concentrations of the acid mucopolysaccharide fraction of urine may be reduced, which should favor the risk of stone formation. According to the literature (Table 1), hyperuricosuria is found in 15-40% of all patients with calcium oxalate stones. 

Structural variations may be also produced at the microscopical scale and are able to produce significant improvements in our understanding of stressor effects. Observation of the biofilm architecture and characterisation of the different fractions (i.e. algae, bacteria, mucopolysaccharides) may be useful to identify particular effects of toxicants to selective components of the biofilm. The use of confocal laser scanning microscopy remains promising [25]. 

Both the refractory and labile fractions of HMW DOM can be lost from seawater through formation of macrogels that aggregate into marine snow. The labile fraction that is known to participate in marine snow formation are the TEPs, such as mucopolysaccharides found in the mucus sheaths surrounding fecal pellets and plankton colonies. HMW DOM is also lost from seawater via (1) adsorption onto sinking POM and minerals, (2) conversion into POM at the sea surfece by turbulence associated with bursting bubbles, and (3) photochemical degradation. 

Recently Heremans demonstrated mucopolysaccharides in urine after zone electrophoresis by means of an Alcian blue-acid fuchsin staining technique (HI).3 Applied in our laboratory to a curtain after a run of serum, two fractions, references -)- 86.30 and - - 86.12, were demonstrated but do not seem to be regular components of serum, at least not in that high concentration (Fig. 62c). 

Cell fractionation studies of five strains of cyanobacteria indicate that MAAs are located primarily (>90%) within the cytoplasm and not the cell sheaths, walls, or membranes.132 Extracellular placement of MAAs does occur in some cyanobacterial species that posses cellular sheath layers.134135 Extracellular MAAs are covalently bonded to oligosaccharide molecules embedded in the cyanobacterial sheath matrix and provide substantial protection to prevent photobleaching of chlorophyll within the cell. Intracellular or extracellular distributions of MAAs in eukaryotic cells have not been investigated. Based on the high MAA concentrations of Phaeocystis antarctica colonies, it has been suggested that MAAs are associated with the extracellular mucopolysaccharide matrix of the colony.125 This may be a more common phenomenon than currently recognized, and future research efforts will be necessary to further document extracellular occurrence of MAAs in cyanobacteria and algae. 

The contribution of mucus carbon to Phaeocystis organic carbon can be assessed in three different ways. In the first, cells are mechanically separated from the mucus matrix by filtration through GF/C filters. Fractionation by filtration yields contributions of 5-80% of mucus carbon to POC (reviewed by Riegman and Van Boekel 1996). As many have pointed out, however, Phaeocystis cells are fragile and may be disrupted by filtration under pressure (Veldhuis and Admiraal 1985 Van Rijssel et al. 1997 Mathot et al. 2000). By releasing their water soluble carbon the fraction of mucus-carbon may be overestimated. On the other hand, mucopolysaccharides may form gels on the filter (Chin et al. 1998) as a result of which their contribution may be underestimated. Therefore, all studies in which colonies were fractionated by filtration or centrifugation have to be interpreted with care. 

In the case of the water-soluble polysaccharides of sweet corn, Zea mays, it has been reported that 66% acetic acid fractionates these polysaccharides. A modification of this general procedure is to precipitate the polysaccharide, from aqueous solution containing different metal ions, with organic solvents. This technique is satisfactory for mixtures of the acid mucopolysaccharides if calcium ions or barium ions are used. 

B35. Bowness, J. M., Fractionation of acidic mucopolysaccharides on columns containing celite and calcium phosphate. Methods Carhohyd. Chem. 5, 18-20 (1965). 

Flodin and Aspberg (1961) have reported a marked separation of oligosaccharides on a column of gel of small pore size. Ringertz (1960) has reported the fractionation of acid polysaccharides from mouse tumors on a Sephadex column. The fractions differed in several properties, including the type of amino sugar present. Tanaka (1966) has reported on the fractionation and isolation of acid mucopolysaccharides. 

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