University of Antwerp, Department of Biology, Laboratory for Ecophysiology, Biochemistry and Toxicology, Groenenborgerlaan, Antwerp, Belgium.
J Biotechnol. 2011 Oct 10;155(4):361-9. doi: 10.1016/j.jbiotec.2011.06.043. Epub 2011 Aug 4.
Chloramphenicol (Cam), although an effective antibiotic, has lost favour due to some fatal side effects. Thus there is an urgent need for rapid and sensitive methods to detect residues in food, feed and environment. We engineered DNA aptamers that recognize Cam as their target, by conducting in vitro selections. Aptamers are nucleic acid recognition elements that are highly specific and sensitive towards their targets and can be synthetically produced in an animal-friendly manner, making them ethical innovative alternatives to antibodies. None of the isolated aptamers in this study shared sequence homology or structural similarities with each other, indicating that specific Cam recognition could be achieved by various DNA sequences under the selection conditions used. Analyzing the binding affinities of the sequences, demonstrated that dissociation constants (K(d)) in the extremely low micromolar range, which were lower than those previously reported for Cam-specific RNA aptamers, were achieved. The two best aptamers had G rich (>35%) nucleotide regions, an attribute distinguishing them from the rest and apparently responsible for their high selectivity and affinity (K(d)∼0.8 and 1μM respectively). These aptamers open up possibilities to allow easy detection of Cam via aptamer-based biosensors.
氯霉素（Cam）虽然是一种有效的抗生素，但由于一些致命的副作用而失宠。因此，迫切需要快速、灵敏的方法来检测食品、饲料和环境中的残留物。我们通过体外选择，设计了能够识别 Cam 的 DNA 适体。适体是一种核酸识别元件，对其靶标具有高度特异性和敏感性，并且可以以对动物友好的方式合成生产，使它们成为替代抗体的具有伦理道德的创新替代品。本研究中分离出的适体彼此之间没有共享序列同源性或结构相似性，这表明在使用的选择条件下，各种 DNA 序列可以实现对特定 Cam 的识别。分析这些序列的结合亲和力表明，解离常数（Kd）达到了极低的微摩尔范围，低于先前报道的 Cam 特异性 RNA 适体的解离常数。两个最佳的适体具有富含 G（>35%）的核苷酸区域，这一属性使它们与其他适体区分开来，显然是它们高选择性和亲和力的原因（Kd 分别约为 0.8 和 1μM）。这些适体为基于适体的生物传感器轻松检测 Cam 开辟了可能性。
