The Application Of Novel Nucleic Acid Probe In The Detection Of Transgenic Food

In recent years, so many kinds of genetically modified crops have beenlarge-scale commercially cultivated and selled because of their advantages, forexample, increasing production and nutritional value, disease and insect resistance.However, the possible security problems of transgene to human beings and theenvironment have not been accurately predicted with the present science andtechnology. To satisfy consumers’ right to know and right of choice and for the sakeof international trade, many countries in the world have established their ownlabeling system and administrative statute for GMOs. Meanwhile, the threshold oftransgene in genetically modified food is lower and lower. As a result, the detectionmethods of genetically modified food have caused the great attention of governmentsand the related food inspection institutions. At present, internationally still has nounified qualitative and quantitative detection system of genetically modified foods.As a result, the development of determination of genetically modified food is verymeanful.In order to explore the detection method of transgene in genetically modifiedfood, a specific, simple and label-free sensor has been developed. The sensor hasbeen used to detect target CaMV35S promoter with three different reaction systemsand related instruments, and also the possible mechanism has been proposed.The thesis consists of4chapters. In chapter1, the genetically modified food hasbeen described detailedly, such as the concept, trait, situation of study, the transgenecontained in GMC, the detection methods and so on. Otherwise, the researchprogress of G-quadruplex, combination of G-quadruplex and hemin and theapplication of the complex have also been introduced in detail.In chapter2, probes with G-rich sequences have been designed in threedifferent split modes and probes in2:2split mode having the best sensitivity havebeen chosen to detect transgene CaMV35S promoter. The binary probes can foldinto G-quadruplex structure in the presence of DNA-T and then combine with heminto form a DNAzyme resembling horseradish peroxidase. And the DNAzyme cancatalyze the reaction of ABTS2-with H2O2. Based on the principle, a visible,selective and simple sensor has been built to detect transgene. In chapter3, the probes in2:2split mode shape a DNAzyme with hemin in theprence of target DNA, and then the reaction system of H2DCFDA with H2O2iscatalyzed by the DNAzyme. And then a selective, sensitive and lable-free fluorescentsensor has been developed to detect transgene.In chapter4, the binary probes in2:2split mode have also been utilized. In theprence of target gene, the DNAzyme shaped by probes and hemin has great catalyticactivity in the reaction of luminol with H2O2and then the reaction system givesstronger luminescence signal. Based on the principle, a sensitive chemiluminescentsensor has been proposed to detect transgene.At last，the research work of this thesis has been summarized，and the furtherstudy of this research has been proposed.