Sialic acids (Sia) are terminal components of glycoconjugates that are involved in molecular and cellular interactions in the olfactory system. Diverse glycoconjugates are expressed in the salamander olfactory projection; however, their sialylation and the linkage of Sia to underlying sugars remain largely unknown. The present study aimed to determine the expression of Sia linked to galactose (Gal)-N-acetylglucosamine and N-acetylgalactosamine (GalNAc) in the olfactory bulbs of three species of salamanders using lectin binding. Abundant distribution of sialoglycoconjugates was observed in the salamander olfactory bulb by lectins, Sambucus sieboldiana (SSA) and Maackia amurensis (MAM). Moreover, SSA and MAM showed heterogeneous bindings in the primary olfactory projection of Cynops pyrrhogaster and C. orientalis. Lectin reactivities obviously decreased in all layers of the olfactory bulb after sialidase digestion, indicating selective binding to sialoglycoconjugates. Next, we examined the expression of the subterminal sugar residues, Gal and GalNAc, after terminal Sia removal. Desialylation in the olfactory bulb enhanced the reactivity of Jacalin and Vicia villosa (VVA) lectins that recognize Gal and GalNAc respectively. Together with the binding of SSA and MAM, Sia linked to Gal and GalNAc might be a major component of sialoglycoconjugates in the salamander olfactory projection.

唾液酸 (Sia) 是糖缀合物的末端成分，参与嗅觉系统中的分子和细胞相互作用。蝾螈嗅觉投射中表达了多种糖缀合物；然而，它们的唾液酸化和 Sia 与潜在糖的联系在很大程度上仍然未知。本研究旨在使用凝集素结合确定三种蝾螈嗅球中与半乳糖 (Gal)-N-乙酰氨基葡萄糖和 N-乙酰半乳糖胺 (GalNAc) 相关的 Sia 的表达。通过凝集素、接骨木(SSA) 和Maackia amurensis (MAM)在蝾螈嗅球中观察到唾液酸糖缀合物的丰富分布。此外，SSA 和 MAM 在初级嗅觉投射中表现出异质性结合。Cynops pyrrhogaster和C. orientalis。唾液酸酶消化后，嗅球所有层的凝集素反应性明显降低，表明与唾液酸糖缀合物的选择性结合。接下来，我们检查了末端 Sia 去除后亚末端糖残基 Gal 和 GalNAc 的表达。嗅球中的去唾液酸化增强了分别识别 Gal 和 GalNAc的 Jacalin 和Vicia villosa (VVA) 凝集素的反应性。连同 SSA 和 MAM 的结合，与 Gal 和 GalNAc 相连的 Sia 可能是蝾螈嗅觉投射中唾液酸糖缀合物的主要成分。