Lee Hyeyoung, Garrido Daniel, Mills David A, Barile Daniela
Department of Food Science and Technology, University of California, Davis, CA, USA; Foods for Health Institute, University of California, Davis, CA, USA.
Electrophoresis. 2014 Jun;35(11):1742-50. doi: 10.1002/elps.201300653. Epub 2014 Mar 20.
Gangliosides are receiving considerable attention because they participate in diverse biological processes. Milk gangliosides appear to block pathogen adhesion and modify the intestinal ecology of newborns. However, the interaction of milk gangliosides with gut bifidobacteria has been little investigated. The digestion products of a mixture of gangliosides isolated from milk following incubation with six strains of bifidobacteria were studied using nanoHPLC Chip Q-TOF MS. To understand ganglioside catabolism in vitro, the two major milk gangliosides--GM3 and GD3--remaining in the media after incubation with bifidobacteria were quantified. Individual gangliosides were identified through postprocessing precursor ion scans, and quantitated with the "find by molecular feature" algorithm of MassHunter Qualitative Analysis software. Bifidobacterium infantis and B. bifidum substantially degraded the GM3 and GD3, whereas B. longum subsp. longum and B. animalis subsp. lactis only showed moderate degradation. MALDI FTICR MS analysis enabled a deeper investigation of the degradation and identified ganglioside degradation specifically at the outer portions of the glycan molecules. These results indicate that certain infant gut-associated bifidobacteria have the ability to degrade milk gangliosides releasing sialic acid, and that these glycolipids could play a prebiotic role in the infant gut.
神经节苷脂正受到广泛关注，因为它们参与多种生物过程。母乳中的神经节苷脂似乎能阻止病原体黏附，并改变新生儿的肠道生态。然而，母乳神经节苷脂与肠道双歧杆菌之间的相互作用鲜有研究。使用纳升液相色谱芯片-四极杆飞行时间质谱仪，研究了从母乳中分离出的神经节苷脂混合物与六种双歧杆菌菌株孵育后的消化产物。为了解神经节苷脂在体外的分解代谢，对与双歧杆菌孵育后培养基中残留的两种主要母乳神经节苷脂——GM3和GD3进行了定量分析。通过对前体离子扫描进行后处理来鉴定各个神经节苷脂，并用MassHunter定性分析软件的“按分子特征查找”算法进行定量。婴儿双歧杆菌和两歧双歧杆菌能大量降解GM3和GD3，而长双歧杆菌亚种和动物双歧杆菌亚种仅表现出中度降解。基质辅助激光解吸电离傅里叶变换离子回旋共振质谱分析能够更深入地研究降解情况，并确定神经节苷脂在聚糖分子外部的特异性降解。这些结果表明，某些与婴儿肠道相关的双歧杆菌具有降解母乳神经节苷脂并释放唾液酸的能力，并且这些糖脂可能在婴儿肠道中发挥益生元的作用。
