Soybean Lectin Binding to the Olfactory System of Xenopus. In: Montalcini RL, Calissano P, Kandel ER, Maggi A, editors. Molecular Aspects of Neurobiology. Berlin: Springer Berlin Heidelberg; 1986. pp. 172-5. [DOI: 10.1007/978-3-642-70690-5_34]

Histochemical study by lectin binding of surface glycoconjugates in the developing olfactory system of rat

Lectin-binding histochemistry was used to investigate the distribution and density of defined carbohydrate sequences on the cell surface glycoproteins of the olfactory receptors of rat during development. The olfactory and vomeronasal receptors showed a positive labelling after biotinylated Lycopersicum esculentum lectin binding on embryonic day 16 (E16), while horseradish peroxidase-labelled Glycine max, Bandeiraea simplicifolia (BSA-I) and its B4 isomer BSA-I-B4 agglutinins started to label from day 18 (E18). From this stage onward there was a progressive increase in the intensity and number of lectin-binding olfactory receptors. The first lectin-labelled bundles of axons penetrating the olfactory bulb were observed on E20; from E21 it was possible to identify the first labelled glomeruli that, on the first day (P1) of postnatal life, showed a feature very similar to that of the adult. The lectin staining patterns indicate that during development there are differences in the kind and distribution of saccharidic moieties on the surface of rat olfactory neurons. The possible role of carbohydrate-containing glycoproteins in the reception and transduction of the odours and in the modulation of the cell-cell interactions in the olfactory system is discussed.

Lectins bind differentially to cilia and microvilli of major and minor cell populations in olfactory and nasal respiratory epithelia

Binding of colloidal gold-conjugated lectins was studied in cilia and microvilli of rat olfactory and respiratory epithelia. This was done in sections of rapidly frozen, freeze-substituted specimens embedded in Lowicryl K11M or, for wheat germ agglutinin (WGA) alone, in deep-etched replicas. Olfactory dendritic endings and cilia labeled with WGA and faintly with soybean agglutinin (SBA); olfactory supporting cell microvilli bound only Dolichos biflorus agglutinin (DBA). Microvilli of an infrequent cell bound peanut agglutinin (PNA), SBA, and WGA. These microvilli labeled more strongly with the last two lectins than the olfactory cilia. Respiratory cilia bound WGA and, somewhat more weakly, PNA; microvilli of ciliated respiratory cells bound all four lectins. Visualization of specific labeling improved after preincubation of sections with neuraminidase, except for DBA where lectin binding was abolished. PNA labeling was seen only after neuraminidase preincubation. The densities of membrane surface particles that labeled with WGA corresponded with those of fracture plane particles in a quantitative freeze-fracture, deep-etch analysis. Therefore, a considerable fraction of the WGA-bound particles could reflect transmembrane proteins in olfactory dendritic endings and cilia and in respiratory cilia. The possible nature of these particles is discussed.