Teneberg S, Willemsen P, de Graaf F K, Karlsson K A
Department of Medical Biochemistry, University of Göteborg, Sweden.
FEBS Lett. 1990 Apr 9;263(1):10-4. doi: 10.1016/0014-5793(90)80693-d.
Glycolipids from mucosa scrapings of small intestine of neonatal and adult pigs were tested by the thin-layer chromatogram overlay assay for the binding of Escherichia coli K99. There was practically no binding to acid or non-acid glycolipids of adult pig, known to be resistant to infection with this bacterium. However, piglets, which are susceptible to infection, showed a clear binding to a doublet band in the acid glycolipid fraction. The receptor-active glycolipid was isolated and shown by mass spectrometry, NMR spectroscopy and degradation methods to be NeuGc alpha-3Gal beta 4Glc beta Cer (NeuGc-GM3), the two bands being due to heterogeneity of the ceramide. When tested against various reference glycolipids, NeuAc-GM3 was shown to be inactive. This ganglioside was dominating in adult pig. The apparent developmental disappearance of N-glycolyl groups in glycolipids of intestinal mucosa may have a correspondence in protein-linked sequences as well as thus explain the resistance of adult pigs to infection with E. coli K99.
采用薄层层析覆盖分析法，对新生猪和成年猪小肠黏膜刮片的糖脂进行检测，以确定其与大肠杆菌K99的结合情况。已知成年猪对这种细菌感染具有抗性，其酸性或非酸性糖脂几乎不发生结合。然而，易受感染的仔猪在酸性糖脂部分与一条双峰带表现出明显的结合。分离出具有受体活性的糖脂，并通过质谱、核磁共振光谱和降解方法表明其为NeuGcα-3Galβ4GlcβCer（NeuGc-GM3），这两条带是由于神经酰胺的异质性所致。与各种参考糖脂进行测试时，NeuAc-GM3显示无活性。这种神经节苷脂在成年猪中占主导地位。肠道黏膜糖脂中N-糖基的明显发育性消失可能在蛋白质连接序列中也有对应情况，从而解释了成年猪对大肠杆菌K99感染的抗性。
