针对李斯特菌属的DNA适配体的筛选与鉴定
Selection and characterization of DNA aptamers specific for Listeria species.
作者信息
Suh Soo Hwan, Dwivedi Hari P, Choi Soo Jung, Jaykus Lee-Ann
机构信息
Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA.
Department of Food, Bioprocessing, and Nutrition Sciences, North Carolina State University, Raleigh, NC 27695, USA.
出版信息
Anal Biochem. 2014 Aug 15;459:39-45. doi: 10.1016/j.ab.2014.05.006. Epub 2014 May 20.
Single-stranded (ss) DNA aptamers with binding affinity to Listeria spp. were selected using a whole-cell SELEX (Systematic Evolution of Ligands by EXponential enrichment) method. Listeria monocytogenes cells were grown at 37°C and harvested at mid-log phase or early stationary phase to serve as the targets in SELEX. A total of 10 unique aptamer sequences were identified, six associated with log phase cells and four with stationary phase cells. Binding affinity of the aptamers was determined using flow cytometry and ranged from 10% to 44%. Four candidates having high binding affinity were further studied and found to show genus-specific binding affinity when screened against five different species within the Listeria genus. Using sequential binding assays combined with flow cytometry, it was determined that three of the aptamers (LM6-2, LM12-6, and LM12-13) bound to one apparent cell surface moiety, while a fourth aptamer (LM6-116) appeared to bind to a different cell surface region. This is the first study in which SELEX targeted bacterial cells at different growth phases. When used together, aptamers that bind to different cell surface moieties could increase the analytical sensitivity of future capture and detection assays.
采用全细胞SELEX(指数富集配体系统进化)方法筛选出了对李斯特菌属具有结合亲和力的单链(ss)DNA适配体。将单核细胞增生李斯特菌细胞在37°C下培养,在对数中期或稳定早期收获,用作SELEX中的靶标。共鉴定出10个独特的适配体序列,其中6个与对数期细胞相关,4个与稳定期细胞相关。使用流式细胞术测定适配体的结合亲和力,范围为10%至44%。对4个具有高结合亲和力的候选物进行了进一步研究,发现它们在针对李斯特菌属内的5个不同物种进行筛选时表现出属特异性结合亲和力。通过将顺序结合测定与流式细胞术相结合,确定其中3个适配体(LM6 - 2、LM12 - 6和LM12 - 13)与一个明显的细胞表面部分结合,而第4个适配体(LM6 - 116)似乎与不同的细胞表面区域结合。这是首次针对不同生长阶段细菌细胞进行SELEX的研究。当一起使用时,与不同细胞表面部分结合的适配体可以提高未来捕获和检测测定的分析灵敏度。