长双歧杆菌NCC2705群体感应系统信号分子AI-2的检测

目的:用生物学方法检测长双歧杆菌NCC2705是否产生群体感应系统信号分子AI-2。方法:将长双歧杆菌NCC2705不同时间点的培养上清分别加至AI-2特异报告系统哈氏弧菌BB170中,以空白培养基上清为对照,用荧光光度计对哈氏弧菌发光强度进行计量,推测出长双歧杆菌NCC2705上清中是否含有分泌的AI-2,并由此推断AI-2的活性。结果:通过微孔板检测系统对加入长双歧杆菌NCC2705培养上清的哈氏弧菌BB170进行检测,发现双歧杆菌上清的加入增强了哈氏弧菌BB170发出的荧光强度。结论:长双歧杆菌NCC2705中存在依赖于luxS/AI-2的群体感应系统,并能够分泌有活性的AI-2,为进一步研究长双歧杆菌NCC2705AI-2及luxS基因的功能打下基础。

Detection of the Quorum-Sensing Signal Autoinducer-2 of Bifidobacterium Longum NCC2705

Objective： To explore that if the Bifidobacterium longum NCC2705 produced the quorum-sensing signal autoinducer-2（AI-2） by utilizing a biological assay. Methods： The experiment employs a bioluminescent bacterial reporter strain called Vibrio harveyi BB170, which produces light in response to AI-2. We collected the cellfree culture fluids and add them to the V.harveyi reporter strain. The resulting light production was measured using a luminometer or scintillation counter. AI-2 activity was deduced according to the induction of luminescence of V. harveyi BB170. Results： The fluorescence of the V.harveyi increased after adding the cell-free culture fluids of B. logum NCC2705. Conclusion： We find that the B.logum produces the quorum-sensing signal AI-2, laying the foundation to further study of function of AI-2 from B.logum.