From 2011.igem.org
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Safety
Safety proposal
1.
For the realization of our project we will use the E. coli K-12 derivative DH5α, which is a debilitated strain of the pathogenic wild type E. coli. It lacks cell wall components important for recognition and adherence to intestinal epithelial cells and is hence not able to colonize the intestinal tract of neither humans nor animals. The cultivation of E. coli K-12 derivative strains under laboratory conditions further decreases its ability to colonize the intestine and they are, additionally, easily excluded by the microbiota present in the human colon. Furthermore, E. coli K-12 derivatives are susceptible to stomach acid and can survive it only when introduced in basically buffered media. It does not appear to produce significant amounts of toxins and lacks also other virulence factors. The likelihood of reversion to a pathogenic strain is very low, since E. coli K-12 is a deletion mutant. There is currently no data available which suggests adverse effects of E. coli K-12 on plants or on other microorganisms in the environment. To sum up, E. coli K-12 has a long history of safe use (over 80 years), it has been shown to be avirulent, and the genetic lesions are well understood. It is therefore assigned to the lowest hazard group 1 and can be handled safely at Containment Level 1.
None of the sequences we plan to insert is known to be toxic or to possess any other harmful properties to neither human/animal health nor the environment. The engineered organism does not secrete nor produce any chemically active products. The used vectors are without exception non-conjugative, which reduces the chance of horizontal tranfer of antibiotic resistances. Thus, our engineered organism will not exhibit any additional hazardous properties to the host organism. The engineered organism is designed for laboratory usage only. No release into the environment or exposure to people is required for the realization of our project. Although we apply good laboratory practice during the work in our lab, we may assume a small chance of unintended release of the engineered organism into the environment. Because of the above mentioned reasons we do not expect any adverse effects on environment or public. In case of changes of function of one or several bioparts due to mutation, we can foresee two scenarios: First, as the working of our system depends on fine tuned parameters, a change would most likely prevent the whole system from working at all. Second, a mutation could cause a continuous activation of one of the output signals. As our output signals are represented by non-toxic proteins we also do not expect any adverse effects in this situation.
2.
All sequences which will be inserted into the host organism are already registered BioBricks. Nevertheless, we intend to make new BioBrick devices which assemble known Biobricks into auto-inducing loop devices. As the involved proteins do not exhibit toxicity or other hazardous properties, our new BioBrick devices do not raise any safety issues.
As we plan to make the input, as well as the output signal exchangeable, it is still important to assess which events will lead, for example, to an excessive production of the ouput signal. Especially, if the non-hazardous proteins we will use, are exchanged for more critical proteins, in terms of safety. For this purpose we will try to implement an in silico simulation that will help us to identify the weak points in our system, and to prevent unlikely unexpected scenarios.
3.
We had the opportunity to talk to a Biological Safety Officer of our University about the potential safety issues of our project. As we are working with a non-infectious host organism, none of the inserts possess hazardous properties, and we will only use non-conjugative vectors, applying good laboratory practice and fullfilling Containment Level 1 will be sufficient to minimize the risks for both us, the researches, and the environment.
4.
References
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