HISTOLOGY AND HISTOPATHOLOGY

Cellular and Molecular Biology

 

Histochemical study of glycoconjugates in the toadfish Halobatrachus didactylus oesophagus epithelium

S. Desantis1, F. Cirillo1, M. Deflorio1, P. Megalofonou2, J.L. Palazón3, C. Sarasquete3 and G. De Metrio1

1Department of Animal Health and Well-being, Faculty of Veterinary Medicine, University of Bari, Italy, 2Department of Biology, University of Athens, Greece and 3Instituto de Ciencias Marinas de Andalucía, CSIC, Campus Universitario Rio San Pedro, Puerto Real, Cádiz, Spain


Offprint requests to: Professor Gregorio De Metrio, Dipartimento di Sanità e Benessere degli Animali, Facoltà di Medicina Veterinaria, Università degli Studi di Bari, S.P. per Casamassima Km. 3, I-70010 Valenzano (BA), Italy. e-mail: g.demetrio@veterinaria.uniba.it


Summary. The carbohydrate expression in the epithelium lining the oesophagus of the toadfish Halobatrachus didactylus was studied by means of conventional and lectin histochemistry. The stratified epithelium was constituted by basal cells, polymorphous cells in the intermediate layer, pyramidal and flattened cells in the outer layer and contained two types of large secretory cells: goblet cells and sacciform cells. PAS, Alcian blue pH 2.5 and pH 1.0 stained very strongly the goblet cells, weakly the surface of the other epithelial cells but did not stain the sacciform cells. The goblet cells cytoplasm contained oligosaccharides with terminal Galß1,3GalNAc, alpha/ßGalNAc, Galß1,4GlcNAc, alphaL-Fuc and internal ßGlcNAc residues (PNA, SBA, RCA120, UEA I, LTA and KOH-sialidase-WGA affinity). Galß1,4GlcNAc, alphaL-Fuc and internal ßGlcNAc were also found in the glycocalyx. The sacciform cells expressed sialyloligosaccharides terminating with Neu5Acalpha2,3Galß1,4GlcNac, Neu5Acß2,6Gal/GalNAc, Neu5AcForssman pentasaccharide (MAL II, SNA, KOH-sialidase-DBA staining) as well as asialo-glycoconjugates with terminal/internal alphaMan (Con A affinity) and with terminal Galß1,3GalNAc, Forssman pentasaccharide, Galß1,4GlcNAc, GalNAc (HPA and SBA reactivity), alphaGal (GSA I-B4 reactivity), D-GlcNAc (GSA II labelling), alphaL-Fuc. The basal cells cytoplasm exhibited terminal/internal alphaMan and terminal Neu5Acalpha2,6Gal/GalNAc, Galß1,4GlcNAc, alpha/ßGalNAc, alphaGal, GlcNAc, alphaL-Fuc. Intermediate cells showed oligosaccharides with terminal/internal alphaMan and/or terminating with Neu5Acalpha2,6Gal/GalNAc, Galß1,4GlcNAc in the cytoplasm and with Neu5Acalpha2,3Galß1,4GlcNac, alpha/ßGalNAc, alphaGal, GlcNAc, alphaL-Fuc in the glycocalyx. The pyramidal cells expressed terminal/internal alphaMan and terminal Neu5Acalpha2,6Gal/GalNAc, alpha/ßGalß1,4NAc, alphaGal, alphaL-Fuc in the entire cytoplasm, terminal Neu5acalpha2,3Galß1,4GlcNac and Forssman pentasaccharide in the apical extension, internal ßGlcNAc and/or terminal alphaL-Fuc in the luminal surface, Neu5Acalpha2,3Galß1,4GlcNac, Neu5Acalpha2,6Gal/GalNAc, Galß1,4GlcNAc, alphaGal in the basolateral surface. The flattened cells displayed glycans with terminal/internal alphaMan and terminal Neu5Acalpha2,6Gal/GalNAc, alpa/ßGalNAc, alphaGal, D-GlcNAc in the entire cytoplasm, glycans terminating with Galß1,3GalNAc and/or internal ßGlcNAc in the sub-nuclear cytoplasm . Histol Histopathol 22, 23-35 (2007)

Key words: Glycoconjugates, Lectin histochemistry, Oesophagus, Toadfish

DOI: 10.14670/HH-22.23