基于荧光漂白恢复技术检测乳脂肪球膜上生物分子的流动性Biomolecules mobility on milk fat globule membrane using fluorescence recovery after photobleaching (FRAP)

Abstract

为了推动乳制品的精准评价，采用高分辨率激光共聚焦显微镜（CLSM）结合多荧光探针技术观察乳脂肪球的微观结构，并利用荧光漂白恢复技术（fluorescence recovery after photobleaching，FRAP）定量检测母乳、牛乳、羊乳中乳脂肪球膜上生物分子的流动性。结果表明：3种乳的微观结构基本一致，均出现了新月区，证明了新月区是局部磷脂富集区；乳脂肪球中甘油三酯和水溶性蛋白质的动态分子比例较高，极性脂质和磷脂酰胆碱的动态分子比例较为接近，鞘磷脂的动态分子比例最差；牛乳中甘油三酯的流动性慢于母乳和羊乳，母乳中极性脂的流动性最慢。FRAP可以直观地表征乳脂肪球膜上生物分子的流动性，可为乳状液中膜界面的生化特性研究提供新的方法。 In order to promote the accurate evaluation of milk products, a high-resolution confocal laser microscope (CLSM) combined with multi-fluorescence probe technology was used to observe the microstructure of different mammalian milk, including human milk, cow milk, and goat milk, and fluorescence recovery after photobleaching (FRAP) was used to quantitatively detect the biomolecules mobility on the milk fat globule membrane in different mammalian milk.The results showed that the microstructures of the three kinds of milk were basically the same,and crescents areas appeared in the CLSM diagram of the three kinds of milk were proved to be the local phospholipids enrichment areas. The mobile fraction of triacylglycerol and water soluble proteins in milk fat globules was relatively high, the mobile fraction of polar lipids and phosphatidylcholine in different milk was relatively close,while the sphingomyel showed the lowest mobile fraction. The mobility of triglycerides in cow milk was slower than that of goat milk and human milk, and the mobility of polar lipids in human milk was the slowest. FRAP could intuitively characterize the biomolecules mobility on the milk fat globule membrane, and could provide a new method for the study of the biochemical properties of the membrane interface in the emulsion.

Keywords

• 母乳脂；乳脂肪球膜；极性脂；荧光漂白恢复技术（frap）；流动性
• human milk fat； milk fat globule membrane； polar lipids； fluorescence recovery after photobleaching; mobility