Histochemical demonstration of two subtypes of O-linked oligosaccharides in the rat gastric glands.
The gastric glands synthesize glycoproteins whose oligosaccharides are linked to the peptide core mainly by the O-glycosidic bond, specifically removed by beta-elimination procedure. Our aim was to research the possibility of the existence of two subtypes of O-linked oligosaccharides with a different behavior to the removal procedure. The lectins from peanut (PNA) and Maackia amurensis (MAA-I) were histochemically used as markers of the O-linked oligosaccharides. Sections were also pretreated with beta-elimination and/or peptide N-Glycosidase F (PNGase-F) for the specific removal of O- and N-linked oligosaccharides, respectively. The lectin GNA, which mainly labels to N-linked oligosaccharides, was used to test the correct working of PNGase-F. To test the possibility that the beta-elimination treatment could remove the terminal sialic acid residues, the lectin LFA was used. The surface epithelium was negative to PNA, while it became strongly positive when beta-elimination was performed for 1 day. This staining was resistant to PNGase-F, suggesting that PNA was labeling to O-linked oligosaccharides. However, after beta-elimination for 5 days this staining is not observed. A similar pattern appeared with MAA-I. We propose the existence of two subtypes of O-linked oligosaccharides: labile and resistant. The labile O-linked oligosaccharides are removed with beta-elimination for 1 day, unmasking the PNA-positive oligosaccharides. These oligosaccharides are resistant O-linked oligosaccharides because staining is abolished with longer treatment of beta-elimination. The results with MAA-I also support this suggestion. In summary, the labile O-linked oligosaccharides are removed with short treatment, while the resistant O-linked oligosaccharides need a stronger procedure (for 5 days).
Gómez-Santos
Laura
L
Department of Cell Biology and Histology, School of Medicine and Dentistry, University of the Basque Country, E-48940 Leioa, Vizcaya, Spain.
Alonso
Edurne
E
Ferrer
Concepción
C
Zuasti
Adelina
A
Sáez
Francisco José
FJ
Madrid
Juan Francisco
JF
D000818:Animals; D002236:Carbohydrate Conformation; D005753:Gastric Mucosa / Q000737:chemistry* / Q000166:cytology*; D008297:Male; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D019887:Peanut Agglutinin / Q000378:metabolism; D037121:Plant Lectins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D009844:Oligosaccharides; D019887:Peanut Agglutinin; D037121:Plant Lectins