Al-Banaw A, Kenngott R, Al-Hassan J M, Mehana N, Sinowatz F
Medical Laboratory Sciences Department, Kuwait University, Sulaibekhat, Kuwait.
Anat Histol Embryol. 2010 Feb;39(1):42-50. doi: 10.1111/j.1439-0264.2009.00977.x. Epub 2009 Oct 15.
A histochemical study using conventional carbohydrate histochemistry (periodic-acid staining including diastase controls, alcian blue staining at pH 1 and 2.5) as well as using a battery of 14 fluorescein isothiocyanate (FITC)-labelled lectins to identify glycoconjugates present in 10 different areas of the skin of a catfish (Arius tenuispinis) was carried out. The lectins used were: mannose-binding lectins (Con A, LCA and PSA), galactose-binding lectins (PNA, RCA), N-acetylgalactosamine-binding lectins (DBA, SBA, SJA and GSL I), N-acetylglucosamine-binding lectins (WGA and WGAs), fucose-binding lectins (UEA) and lectins which bind to complex carbohydrate configurations (PHA E, PHA L). Conventional glycoconjugate staining (PAS staining, alcian blue at pH 1 and 2.5) showed that the mucous goblet cells contain a considerable amount of glycoconjugates in all locations of the skin, whereas the other unicellular gland type, the club cells, lacked these glycoconjugates. The glycoproteins found in goblet cells are neutral and therefore stain magenta when subjected to PAS staining. Alcian blue staining indicating acid glycoproteins was distinctly positive at pH 1, but gave only a comparable staining at pH 2.5. The mucus of the goblet cells therefore also contains acid glycoproteins rich in sulphate groups. Using FITC-labelled lectins, the carbohydrate composition of the glycoproteins of goblet cells could be more fully characterized. A distinct staining of the mucus of goblet cells was found with the mannose-binding lectins LCA and PSA; the galactosamine-binding lectins DBA, SBA and GLS I; the glucosamine-binding lectin WGA; and PHA E which stains glycoproteins with complex carbohydrate configurations. No reaction occurred with the fucose-binding lectin UEA and the sialic acid-specific lectin SNA. In addition, the galactose-binding lectins PNA and RCA showed only a weak or completely negative staining of the mucus in the goblet cells. The specificity of the lectin staining could be proved by inhibiting binding of the lectins by competitive inhibition with the corresponding sugars. From these data, we can conclude that the mucus produced by the epidermal goblet cells of A. tenuispinis is rich in mannose, N-acetylgalactosamine and N-acetylglucosamine residues.
开展了一项组织化学研究，使用传统的碳水化合物组织化学方法（过碘酸染色，包括淀粉酶对照、pH值为1和2.5时的阿尔辛蓝染色），以及使用一组14种异硫氰酸荧光素（FITC）标记的凝集素来鉴定鲶鱼（细棘阿里鲇）皮肤10个不同区域中存在的糖缀合物。所使用的凝集素包括：甘露糖结合凝集素（刀豆球蛋白A、扁豆凝集素和豌豆凝集素）、半乳糖结合凝集素（花生凝集素、蓖麻凝集素）、N-乙酰半乳糖胺结合凝集素（双花扁豆凝集素、大豆凝集素、荆豆凝集素和麦芽凝集素I）、N-乙酰葡糖胺结合凝集素（小麦胚凝集素和小麦胚凝集素变体）、岩藻糖结合凝集素（荆豆凝集素）以及结合复杂碳水化合物构型的凝集素（PHA-E、PHA-L）。传统的糖缀合物染色（PAS染色、pH值为1和2.5时的阿尔辛蓝染色）显示，黏液杯状细胞在皮肤的所有部位都含有大量糖缀合物，而另一种单细胞腺类型，即棒状细胞，则缺乏这些糖缀合物。杯状细胞中发现的糖蛋白呈中性，因此在进行PAS染色时染成品红色。指示酸性糖蛋白的阿尔辛蓝染色在pH值为1时明显呈阳性，但在pH值为2.5时仅呈现类似的染色。因此，杯状细胞的黏液中也含有富含硫酸基团的酸性糖蛋白。使用FITC标记的凝集素，可以更全面地表征杯状细胞糖蛋白的碳水化合物组成。发现甘露糖结合凝集素LCA和PSA、半乳糖胺结合凝集素DBA、SBA和GLS I、葡糖胺结合凝集素WGA以及对具有复杂碳水化合物构型的糖蛋白染色的PHA-E对杯状细胞的黏液有明显染色。岩藻糖结合凝集素UEA和唾液酸特异性凝集素SNA未发生反应。此外，半乳糖结合凝集素PNA和RCA对杯状细胞中的黏液仅显示弱阳性或完全阴性染色。凝集素染色的特异性可以通过用相应糖类进行竞争性抑制来证明凝集素的结合来证实。从这些数据中，我们可以得出结论，细棘阿里鲇表皮杯状细胞产生的黏液富含甘露糖、N-乙酰半乳糖胺和N-乙酰葡糖胺残基。
