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Team:BIT
From 2013.igem.org
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HEXAVALENT CHROMIUM
Some illegal dairies always add leather hydrolysate into fresh milk and powdered milk to increase the percentage of protein in milk. Chromate, which is one of the elements of leather dye, is the main element that can be used to trace leather hydrolysate. Our Cr(Ⅵ)-biosensor is thus designed for the detection of chromate in dairy products.
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TETRACYCLINE
Our detection of tetracycline, one of the antibiotics that are widely used in modern dairy industry to prevent the infection of cow breasts, was realised by two inhibitor proteins, LacI and TetR. When certain chemicals, such as tetracycline and IPTG, are added, they will prevent the inhibitor from binding to their respective promoters. Thus, the promoters will be unlocked and the green fluorescence protein will be produced.
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SIGNAL
Besides the three bio-sensors, we introduced an amplifier and a controller so that the output signal could be amplified by adjusting the concentration of IPTG to achieve the adjustment of magnification. In order to achieve real-time detection, we also made a biochip, which provided a reaction room for both engineering bacteria and samples, in a hand-held electronic equipment made by ourselves.
CONTACT US
- Beijing Institute of Technology
- Address: 5 South Zhongguancun Street, Haidian District, Beijing, China
- Postcode: 100081
- E-mail：yifei0114@bit.edu.cn
PICTURES
A Brief Introduction of Integrated Sensor for Detection of Milk Product
As we know, antibiotics are widely used in modern industry to prevent the infection of cow breasts. However, the residual of antibiotics and other components, such as Cr (VI) which is widely used in the recycle of proteins from leather, will endanger the health of customers. Therefore, it is necessary to find solution to identify these harmful chemicals, but the method of timely detection of harmful chemicals in products still remains unsolved.
To solve this problem, our sensor has been divided into three, respectively, of hexavalent chromium, tetracycline and β-lactam there is a response, for each sensor, we are all assembled in a downstream of the amplification block (amplifier) and the control block (controller), the output signal to be amplified, by adjusting the concentration of IPTG to achieve the adjustment of magnification. Amplifier by the T7 RNA polymerase gene and T7 promoter composition control block is through the downstream of the T7 promoter plus lacO and the addition of regular expression lacI, by adjusting the concentration of IPTG, lacO then adjust the boot situation achieved, the final response module for the green fluorescent protein.
In order to achieve real-time detection, we also made a biochip which provided a reaction room for both engineering bacteria and samples. Now we are able to detect all these three harmful chemicals with a hand-held electronic equipment made by ourselves.
