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Our Tetracycline biosensor can detect the tetracycline residues in agricultural products (such as: meat, eggs, milk, etc.). By using the approach of synthetic biology, our Tetracycline biosensor provides a new way to detect tetracycline. Click here to see the complete achievement.
Currently, the overuse of antibiotics has not been effectively regulated in China. A survey from 4152 Internet users of 31 provinces and autonomous regions in China shows that 74% investigation families have been or have equipped with antibiotics. Moreover, the application rate of antibiotics in hospitalized patients is 80% in China, far more than the international standards (30%).
Many problem stems are from overuse and misuse of antimicrobial agents in human medicine, however, large-scale use of antimicrobials in agriculture also contributes to the crisis. For treatment, prevention of diseases and the need of promoting animal growth, some of the farmers use antibiotics extensively which cause the rise of antibiotic-resistant pathogens. Yonghong Xiao, professor of Clinical Pharmacology Research Institute of Peking University, pointed out that the annual production of raw materials antibiotics close to 210,000 tons, while 97,000 tons antibiotics is used in livestock breeding industry, which accounted for 46.1% of the total production.
The misuse of antibiotics is endangering human health and ecological balance. In terms of medicine use, we can develop standards to use antibiotics reasonably. But agricultural uses of antibiotics produce environmental exposures in a variety of reservoirs, which are impossible to be guarded against. Our group hopes to use synthetic biology method to provide a simple, reliable and efficient method for detecting the antibiotics.
After investigation, we choose tetracycline as the research object because of its extensive existence in animal husbandry. The overuse and misuse of antibiotics of tetracycline class may make these drugs residues in edible animal, which will cause a damage in human liver, kidney and digestive tract. A long-term residue will also make the bacteria microbial tolerance, which may cause a double infection.
Whereas，Currently antibiotics (including tetracycline) detection methods are more complex. Not only the instruments are very expensive, but also the cost of detection is high, which brings many inconvenience to the sample detection. Our group hopes to use synthetic biology to provide a simple, reliable and efficient method for the detection of antibiotics. And we hope it can serve testing organizations and the ordinary families to ensure their food safe.
Our group constructed the tetracycline inducible expression system. And through plasmid mediated, the system was transfected into Escherichia coli TOP10 and GS115 Pichia pastoris. It can generate a rtTA transcription activation factor in cells. RtTA combining with tetracycline antibiotics can activate the fluorescent protein expression system, which can instructs the tetracycline class of antibiotics by fluorescence detection.
rtTA: combined with rTetR (reverse TetR) and VP16 transcriptional activation of regional. RTetR derived from the mutation of the 4 amino acids in TetR.
The fluorescent protein expression system: TRE (Tet-responsive element), PminCMV (minimal CMV minimal promoter promoter) and fluorescent protein gene composed of it.