Histochemical studies of epithelial cell glycoproteins in normal rat colon

Abstract

Two general classes of glycoproteins have been identified in the colonic epithelial cells of the Sprague Dawley rat. Glycoproteins belonging to the first of these classes contain sialic acids both with and without side chain o-acyl substituents, abundant o-sulphate ester and 'neutral sugars' (hexose, 6-deoxyhexose or N-acetyl hexosamine residues) with oxidisable vicinal diols and are located in the goblet cells of the descending colon and in goblet cells populating the upper halves of the crypts of the ascending colon. In the descending colon, the sulphosialoglycoproteins in the goblet cells in the base of the crypts contain sialic acids without side chain o-acyl substituents. It appears that as these cells migrate up the crypts, there is o-acylation of the side chains of the sialic acids of the glycoproteins and an increase in the quantity of 'neutral sugars' without a corresponding increase in sialic acid. Glycoproteins with similar properties to those of the goblet cells of the upper halves of the crypts of the descending colon, but containing less sulphate, are found in the goblet cells of the upper half of the crypts of the ascending colon. The second general class of glycoproteins contain sialic acids all, or almost all of which, are substituted at position C8 and only relatively small quantities of sulphate. They are located in the mucous cells of the descending colon, the deep crypt secretory cells of the ascending colon and the columnar absorptive cell brush border.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycoconjugates in the branchial mucous cells of <i>Cynoscion guatucupa</i> (Cuvier, 1830) (Pisces: Sciaenidae)

“…The mucus may act as an important diffusion barrier allowing ion absorption without direct contact between sea water and the epithelial cells (Shephard, 1982). Moreover, glycoconjugates containing O-sulphate esters have a lubricant role (Park et al, 1987;Mittal et al, 1994Mittal et al, , 1995. A protection activity against bacterial and viral invasion has been associated with glycoconjugates containing sialic acid residues (Suprasert et al, 1987).…”

Histochemical characterization of glycoproteins in the gills of the carp

“…Mucus producing cells integrate a variety of critical functions. Physiologically, mucus is important for protection and inhibition of micro-organisms (5,27,36). This function is occurred by mucous glycoproteins (GPs) (5,15,24,35), as well as the GPs are identified with O-sulphate esters are responsible for the lubrication (8).…”

Mucous Cells in the Gills of Snow Trout, Schizothorax curvifrons Heckel (Pisces, Cypriniformes, Cyprinidae)

“…Vertebrate mucous cells and their secretion products have been studied both from the histochemical and ultrastructural point of view (Hafez 1977, Pack et al 1981, Park et al 1987, Tesik 1984, Suprasert et al 1987. Various types of mucous cells involved in mucous secretion have been found in the epidermis of fish (Whitear 1986, Agrawal and Mittal 1992, Mittal et al 1994, 1995, Fishelson 1996.…”

“…Mucous secretion has been mainly related to lubrication and protection against pathogenic micro-organisms (Whitear 1986, Park et al 1987, Zaccone et al 1989. In fishes this secretion also plays an important role in swimming, defense against pollutants (Fletcher 1978) and in the ion regulation and diffusion of ions (Shephard et al 1982, Handy et al 1989.…”