Confocal evaluation of native and induced lectin binding contributes to discriminate between lingual gland glycocomponents in quail

Abstract

A confocal analysis was performed on the quail (Coturnix coturnix japonica) lingual salivary glands where the carbohydrate chains were studied by lectin histochemistry. For this purpose, appropriate FITC- and TRITC-conjugates were used for double binding also accomplished with sialidase digestion. The glycosidic components of the quail lingual salivary glands were found to be heterogeneously distributed on the different secretory structures as well as on the single secretory elements of each adenomere. The rostra1 portion of the anterior lingual gland was found to only secrete neutral glycocomponents, characterized by terminal β-galactose, N-acetylgalactosamine and fucose residues in contrast to the caudal portion that was shown to be extremely heterogeneous and to produce sialylated glycoconjugates characterized by the terminal sequences sialic acid-β-galactose-N-acetylgalactosamine, sialic acid-13-galactose-N-acetylglucosamine,a nd sialic acid-α-N-acetylgalactosamine partly codistributed within secretory adenomeres. The posterior lingual gland was observed to be the major contributor to the secretion of salivary mucins containing sialoglycoconjugates with terminal sialic acid residues linked to β-galactose-Nacetylgalactosamine or α-N-acetylgalactosamine often located in distinct secretory elements.