基于ＳＯＳ反应及氧化应激反应相关启动子的 辐射生物传感器研究

The radiation environment exists everywhere in the living space, the results of animal experiments in recent years show that the harm of electromagnetic radiation are mainly concentrated on nervous system toxicity, inducing tumors (especially brain tumors, leukemia) and reproductive system damage. Radiation exposure has the characteristics of wide-area, concealed and cumulative effect. It acts on living organisms, causing a large amount of reactive oxygen species (ROS) in cells. By-products of normal aerobic physiological metabolism in the cells can also generate free radicals, thereby causing damage to the body. In other words, radiation can not only directly act on biological molecules and cause damage to the body, but also indirectly act on the body by acting on biological water and so on to produce free radicals. In order to detect the magnitude of radiation toxicity quickly and easily, there been established radiation biosensors. Engineered bacteria sensors carrying SoxR, RecA, Cda and SulA four promoters and enhanced green fluorescent protein (EGFP) fusion gene related to SOS reaction and oxidative stress reaction were constructed, that is, the promoter-reporter system. First, the four biosensors were treated with chemical damage agents, they all expressed a large amount of green fluorescent protein after stimulation, and then -y-ray irradiation was performed. According to the treatment, the sensor with the highest sensitivity was the RecA promoter engineering bacteria sensor under radiation. The promoter-reporter fusion gene obtained by PCR and overlap PCR, and inserted into the vector PUC19, then transformed into E. coli DH5a. After double-enzyme digestion and sequencing verification, the successful engineered bacteria sensors were disposed of chemical oxidant and physical radiation. The results showed that the four engineering bacteria sensors successfully responded to the oxidant hydrogen peroxide and physical radiation, and the green fluorescence intensity gradually increased with the increase of physical radiation dose (0-30Gy). Among them, the green fluorescence of RecA engineered bacteria sensor was the most obvious after stimulation compared with the other sensors. The use of synthetic biology methods to establish physical radiation sensors based on biological effects successfully, with simple preparation, visibility of results, meeting fast, wide range, online monitoring needs, solving the problem of excessive background value in chemical sensors. It has a good application prospect in the measurement of radiation, radiation on the ground and even in the space.