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DictionarySeemucinglycocalyx
glycocalyx[′glī·kō′kā‚liks] (cell and molecular biology) The outer component of a cell surface, outside the plasmalemma; usually contains strongly acidic sugars, hence it carries a negative electric charge. glycocalyx
glycocalyx [gli″ko-kal´iks] the glycoprotein-polysaccharide covering that surrounds many cells.gly·co·ca·lyx (glī'kō-kā'liks), A PAS-positive filamentous coating on the apical surface of certain epithelial cells, composed of carbohydrate moieties of proteins that protrude from the free surface of the plasma membrane. [glyco- + G. kalyx, husk, shell] gly·co·ca·lyx (glī'kō-kā'liks) A filamentous coating on the apical surface of certain epithelial cells, composed of carbohydrate moieties of proteins that protrude from the free surface of the plasma membrane; gives positive test result to periodic acid-Schiff procedure. [glyco- + G. kalyx, husk, shell]glycocalyx a mass of filaments up to 3 μm thick produced by the membrane of intestinal brush-border microvilli, consisting of acid mucopolysaccharide and GLYCOPROTEIN, and thought to be associated with the digestion of small food molecules. Other animal cells also have a glycocalyx, on their cell coat, providing a mechanism that enables cells to recognise each other, an important process in embryonic development.mucinGlycoprotein, rich in carbohydrates, produced by the goblet cells and the subsurface vesicles of the conjunctiva which forms the basis of the mucous layer of the precorneal film. Mucin and the secreted glycocalyx (which consists of glycoproteins) are adsorbed by the epithelium of the cornea to convert it from a hydrophobic into a wettable hydrophilic surface. A deficiency in the production of mucin leads to an abnormally short precorneal film break-up time and to desiccation of the ocular surface. In addition, the mucous layer prevents microbial invasion of the cornea. In some contact lens wearers (especially of silicone hydrogel lenses) collapsed mucin, as well as lipids and tear proteins, accumulate behind the lens and form small, discrete spheres (called mucin balls or mucin plugs). These mucin balls cause neither discomfort nor loss of vision. See precorneal film; keratoconjunctivitis sicca; break-up time test; xerophthalmia. |