食源性细菌威胁着人类的健康。毛细管电泳(CE)是测定细菌的有力分离手段。直接分离细菌的缺点是分辨率低,通道吸附,和细菌聚集。在这项工作中,开发了一种核酸链置换方法,通过CE间接分离细菌。DNA复合物,由探针和适体组成,混合了三种细菌金黄色葡萄球菌,大肠杆菌,还有铜绿假单胞菌.适体可以与细菌特异性结合并释放探针。通过探针的分离,细菌可以通过CE间接确定。该方法避免了直接分离细菌的不足。在优化条件下,通过高速CE和激光诱导荧光检测,可以在2.5min内分离和检测细菌的三种探针。细菌的检出限在4.20×106至1.75×107CFU/mL的范围内。最后,将所开发的方法用于研究共存细菌的拮抗作用,以揭示它们之间的关系。此外,三种中药的抑菌效率,黄连,五味子,和金银花,也用这种方法进行了研究。
Foodborne bacteria threaten human\'s health. Capillary electrophoresis (CE) is a powerful separation means for the determination of bacteria. Direct separation of bacteria suffers from the shortages of low resolution, channel adsorption, and bacterial aggregation. In this work, a method of nucleic acid strand displacement was developed to indirect separate the bacteria by CE. DNA complexes, consisting of probes and aptamers, were mixed with the three bacteria Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The aptamers could specifically bond with bacteria and release the probes. Through the separation of the probes, the bacteria could be indirectly determined by CE. This method avoided the shortages of direct separation of bacteria. Under the optimized conditions, the three probes for the bacteria could be separated and detected within 2.5 min by high-speed CE with laser-induced fluorescence detection. The limits of detection for the bacteria were in the range 4.20 × 106 to 1.75 × 107 CFU/mL. Finally, the developed method was applied on the study of antagonism of the coexistent bacteria to reveal the relationship between them. Furthermore, the efficiency of bacteriostasis of three traditional Chinese medicines, Coptis chinensis, Schisandra chinensis, and honeysuckle, was also studied by this method.