Safety

Interview with Prof. Zhou Shungui

iGEM group：If our project needs to be applied in practice, what will be the specific operation processes? And of what aspects shall we be conscious?

President Shi: Generally speaking, phosphate solubilizing bacteria will be subject to a series of courses to rejuvenate and ferment, and then be colonized in the plant root as the added substance of organic fertilizers. That can control the reproduction of harmful bacteria in soil effectively on one hand and disintegrate phosphorus and potassium on the other hand. In addition to organic fertilizers, something like fermentation liquor of cane sugar, fermentation liquor of alginic salts, etc, is also a good carrier. It is to guarantee an adequate carbon source and nitrogen source that matters. Talking about the aspect you should very care about is safety. Currently, it is unclear whether the unmonitored release of every genetically engineered microbe(GEM) into the enviroment is absolutely harmful or absolutely safe, especially your project, which actually is referring to GMO that has been controversial for almost 20 years in China, even world. Decades of scientific research and changes in government polices may be needed to determine and define the danger or safety of every type of GEM, as current information is sparse.

For Human Practice, we have come up with a common question to President Shi that “If our project needs to be applied in practice, what will be the specific operation processes? And of what aspects shall we be conscious? ”. It is a essential reminder of his answers tha there is the need for constant care. We decided to customize a ‘kill switch’ as a safeguard for our project, simultaneously harbors a neutral statet that allows billions of microbes to happily thrive and avoid unexpectedly escaping of GEMs into the enviroment and transferring of non-natural plasmid DNA to existing soil bacteria. ‘Toggle Switch’, based on a circuit which the LacI and TetR transcription factors are reciprocally repressive, but in which the expression off TetR is favoured owing to modifications in the strength of the ribosommal binding sites of the two transcription factors. Inhibition of TetR expression by anhydrotetracycline(ATc), a compound that is not normally found in nature, is necessary of expression of LacI. LacI directly inhibits expression of a lethal toxin or indirectly prevents inhibition of the expression of our target genes. Removal of ATc from the enviroment activates the expression of TetR, which leads to cell death. For more information about lab, please click here.