Cornea polysaccharide

The chromatographic techniques has been useful for investigations of carbohydrates of animal origin, such as those in human cerebrospinal fluid (90,91), foetal and maternal blood of sheep (202), urines (26,90,134), the polysaccharide components of sea urchin eggs (241), capsular polysaccharides (95), blood group polysaccharides (6,7,10), semm and urinary mucoproteins (94), cornea polysaccharides (258), frog spawn mucin (101), and hyaluronic acid (161). 

The second polysaccharide present in cartilage proteogylcan is keratan sulfate. It is generally found in shorter chains than chondroitin sulfate with an average molecular weight of about 20,000 Da. It is also found in the cornea of the eye. 

Whitehouse and Bostrom provide evidence that, in both cornea and cartilage, salicylic acid and some anti-inflammatory steroids reduce the uptake of extracellular sulphate ions by the tissues and also partially inhibit the incorporation of intracellular inorganic sulphate into the sulphated polysaccharides. 2,3-Dihydroxybenzoic acid is also effective, though to a lesser extent than salicylic acid 2,5- and 2,6-dihydroxybenzoic acids are inactive. The authors suggest that these effects may be due to a common action of the drugs on processes generating ATP within the tissues. In vivo experiments demonstrate that 100 mg/kg of sodium salicylate intraperitoneally inhibits S incorporation into polysaccharide sulphates of rat-rib cartilage. 

Figure 3. Model of protein fibers (dots) and polysaccharide chain molecules (lines) for rabbit cornea...

Keratan sulphates I and II have been isolated and purified from bovine cornea and nasal cartilage, respectively. Desulphation of keratan sulphate I yielded both water-soluble and water-insoluble products, but keratan sulphate II yielded only water-soluble products. The water-soluble form contains glycopeptides from the protein-polysaccharide linkage region, and oligosaccharides derived from the main chain of the glycosaminoglycan associate forming water-insoluble species. 

Biosynthesis.—Each population of fibroblast-like cells from chicken cornea, heart, and skin has been shown to synthesize a pattern of glycosaminoglycans different from the other two, indicating that these cells behave like three distinct and stably differentiated cell types. A comparative study of the uptake of [ S]proteoglycans and [ S] glycosaminoglycans by cultured skin fibroblasts, together with competition experiments, has indicated that during pinocytosis both classes of polysaccharide interact with different receptors on the cell membrane. ... 

Natural sulfate acid esters occur as salts in many seaweed polysaccharides (138). They are also found widely distributed in the polysaccharides (139) of animal tissues (Chapter XII), such as those in skin, cartilage, cornea, and gastric mucin. Heparin (p. 720) (140), the natural blood anticoagulant, is a highly sulfated polysaccharide of this type and contains both sulfate acid ester groups and a sulfamic acid function, RNHSO2OH. 

Sulfaled, protein-bounded polysaccharide found in cartilage, cornea, bones, skin, arteries... 

The presence of hyaluronic acid in the synovial fluid is of particular interest because of its possible involvement in rheumatoid conditions. The reported benefit of treating arthritic patients with salts of glucuronic acid (169, 328) may be connected with this polysaccharide in some obscure way. In the synovial fluid hyaluronic acid is combined with proteins, three of which, albumin, p- and y-seroglobulin, have been found present (158). This protein-polysaccharide complex is characterized by a high viscosity which is believed due largely to the polysaccharide (367). When it was split by hyaluronidase obtained from any of its various sources (certain bacteria, testicle, sperm, skin, cornea, etc.), the viscosity dropped to almost that of water and progressively less cohesive materials could be precipitated by addition of acetic acid. This reduction in viscosity took place in... 

A polysaccharide composed of glucosamine, a hexuronic acid, acetic and sulfuric acid units in equimolar ratio was isolated from bovine cornea by Meyer and Chaffee (266). By rotation and by enzymatic analysis with hyaluronidase obtained from pneumococcus and from testis, they characterized the compound s a sulfuric acid ester of hyaluronic acid. 

The minced tissue, cornea, nucleus pulposus or cartilage, was first treated with proteolytic enzymes, pepsin, tiypsin, or papain. Further removal of the protein, after pepsin treatment, was effected according to Sevag s procedure, or by adsorption on Lloyd s reagent. The polysaccharide mixture vras then fractionated by alcohol precipitation, or by alcohol elution of the barium salt on a cellulose column, or by passage through Dowex-i or Sephadex columns. 

Nunn, J. R. Parolis, H. (1969). Sulphated polysaccharides of the grateloupiaceae family Part III. A polysaccharide from Phyllymenia cornea. Carbohydrate Research, 9, 265-276. 

Melo, MRS Feltosa, JPA Freitas, ALP Paula, RCM. Isolation and characterization of soluble sulfated polysaccharide from the red seaweed Gracilaria cornea. Carbohydrate Polymers, 2002, 49, 491-498. 

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