Lectin binding patterns in the olfactory bulb of mallard ducks (Anas platyrhynchos)

摘要

We histologically examined lectin binding patterns in the olfactory bulb of mallard ducks (Anas platyrhynchos) using 21 biotinylated lectins. Positive staining for the N-acetylglucosamine-specific lectins (Bandeiraea simplicifolia II, Datura stramonium, Lycopersicon esculentum, Solanum tuberosum, Triticum vulgare), galactose or N-acetylgalactosamine-specific lectins (Artocarpus intergrifolia, Phaseolus vulgaris erythroagglutinin, Phaseolus vulgaris leucoagglutinin, Ricus communis) and the mannose-specific lectins (Lens culinaris and Pisum sativum) was observed in the olfactory nerve and glomerular layers. Canavalia ensiformis staining showed a similar pattern to that obtained with the lectins and there was also faint staining in the mitral cells. Olfactory nerve axons terminate in the glomeruli, where they make excitatory synapses with the dendrites of mitral cells. This finding indicates that glycoconjugates that bind Canavalia ensiformis play an important role in formation of glomeruli. No positive staining for the other lectins was seen in the olfactory bulb. Based on these results, we conclude that cell surface sugar moieties of the olfactory bulb in mallard ducks express N-acetylglucosamine and mannose residues rather than N-acetylgalactosamine residues. The carbohydrate composition of mallard duck olfactory bulb differed from that of other vertebrates found in previous studies.