SELEX法筛选炭疽芽孢杆菌适配子的研究

目的：利用SELEX（system evolution of ligands by exponential enrichment)体外筛选,找能与炭疽芽孢杆菌芽孢特异结合的寡核苷酸适配子（aptamer)，方法：体外合成长度为78个核苷酸的随机DNA库，通过SELEX技术，以炭疽牙直菌疫苗株A．16R的芽孢为靶标进行15轮的筛选，利用生物素－亲和素显色系统判断寡核苷酸与牙孢的结合活性，结果：随着筛选轮数的增加，PCR扩增电泳条带渐单纯，寡核苷酸与芽孢结合后显色，D值提高9倍以上，D值随适配子结合量的增加而递增，结论：已初步筛选到与炭疽芽孢具有亲和力的适配子。

In vitro selection of DNA aptamers to Bacillus anthracis spores by SELEX

Objective:To obtain oligonucleotide aptamers which can specifically bind to Bacillus anthracis spores by in vitro selection protocol-SELEX (system evolution of ligands by exponential enrichment).Methods:An in vitro synthesized 78 mer random DNA library (≤1014-15types of different DNAs ) was subjected to 15 rounds of selection using SELEX method against spores of B.anthracis vaccine strain A.16R. Binding of the aptamers to spores was visualized by biotin-streptavidin-horseradish peroxidase system.Results:PCR amplification band pattern of the first round selection was different from that of the ninth round. The binding assay demonstrated that D absorbance at 450 nm of the fifteenth round pool increased 9 times as compared with that of the first round , and the D absorbance increased with the increment of aptamers′ quantity binding to spores. Conclusions: A set of aptamers with considerable binding affinity to B.anthracis spores were successfully selected from the initial random DNA pool.