The Safety Assessment Of Deoxynivalenol And Specificity Determination Of Genetically Modified Rice Kefeng6

The progress of science and technology together with the improvement ofliving standards triggers more attention to food safety. This dissertationconducted two related projects: the development of an analytical methodfor deoxynivalenol (DON) detection in human cells and exploration ofgenotoxicity and cytotoxicity for DON to assess its safety issues andsafeguard human health; the development of a method for qualitative andquantitative detection of genetically modified rice Kefeng6for its efficientsurveillance.1. Detection and mechanism analysis of deoxynivalenol. Mycotoxincontamination has brought huge economic losses to global agriculture.Meanwhile, they also pose serious threat to the fitness of human beingsand animals. This study set up a simple and efficient method based on ultraperformance liquid chromatography-time of flight-mass spectrometry(UPLC-TOF-MS) system to detect deoxynivalenol, one of the mostcommon mycotoxins in grains, in human hepatocellular carcinoma cells(Hep G2) without any clean-up steps, and further validated it. The limits ofdetection (LODs) for both media and cells were25ng/ml, while limits ofquantitation (LOQs) for both matrices were50ng/ml. Furthermore, thisproject also investigated cellular toxicity and genetic toxicity ofdeoxynivalenol in order to find effective methods to reduce or even relieverelated diseases or poisoning for humans and animals. Experimental resultsshowed that the half inhibitory concentration (IC50) of deoxynivalenol inHep G2cells was4.25μM for24hours and that toxin could cause DNAdamage of cells via oxidative stress. Preliminary results of experiment also demonstrated that deoxynivalenol and T2toxin, a toxin in the sametrichothecenes as deoxynivalenol, interacted with each otherantagonistically. This study laid a solid foundation for food quality controladministration to establish control standards for deoxynivalenol, to enforcestrict control of mycotoxin contamination, to prevent actual diseases andguard human health.2. Detection of genetically modified rice Kefeng6. Researches ongenetically modified rice have been carried around the globle since theadvent of the first transgenic rice. Meanwhile, genetically modified rice isalso constantly expanding in the food market. One genetically modifiedrice, Kefeng6, is insect-resistant rice with bt gene and cpti gene. To helpimplementing related regulations on genetically modified crops, thisresearch established a detection method with high specificity andsensitivity by qualitative and quantitative PCR based on the5’ flankingsequences. The LODs of qualitative PCR and quantitative PCR were20copies and10copies, respectively. Meanwhile, the method has passedin-house validation. Experiment demostrated that this method had highamplification efficiency and excellent linear correlation coefficient inquantitative standard curve. The results on positive samples also had highaccuracy and good precision. This study improved the detection system oftransgenic insect-resistant rice and also promoted its safety regulation.