Glycoproteins in the Buccal Epithelium of a Carp, Cirrhinus mrigala (Pisces, Cyprinidae): A Histochemical Profile

Abstract

Glycoproteins (GPs) were visualized histochemically in the secretory cells - the mucous goblet cells (the type A and the type B), the rodlet cells and the epithelial cells in different regions of the buccal cavity of Cirrhinus mrigala. The type A mucous goblet cells, the type B mucous goblet cells, the rodlet cells and the epithelial cells elaborate GPs with oxidizable vicinal diols and GPs with sialic acid residue without O-acyl substitution. The type A mucous goblet cells, in addition, contain moderate amounts of GPs with O-sulphate esters. The type B mucous goblet cells, in contrast, contain high concentrations of GPs with O-sulphate esters. The rodlet cells secrete small amounts of GPs with oxidizable vicinal diols. The analysis of the results elucidates interesting differences in the composition and concentration of GPs in the mucus elaborated by the secretory cells indicating the potential importance of the glycoproteins in the buccal cavity. These GPs could be considered to represent a mechanism for modulation of the composition of the protective mucus layer correlated to specific functions. © 2013 Blackwell Verlag GmbH.