Team:SDU-Denmark/Tour34

Safety

"With great power comes great responsibility!" - Voltaire

The role of a synthetic biologist involves the analysis of the biosafety of the systems designed. Biosafety is the prevention of an accidental or unintentional exposure to pathogens, and to analyze this, it is useful to evaluate the risk involved in the project, which can be expressed as “Risk= Hazard x Probability”. Source: iGEM, 2013: Safety form Resources. (Link)

Hazard

To evaluate the potential hazardousness of our project, we started by looking at the components of the system. Our main chassis, E.coli K12 MG1655 is a non-pathogen E.coli strain. Source: NIH GUIDELINES FOR RESEARCH INVOLVING RECOMBINANT OR SYNTHETIC NUCLEIC ACID MOLECULES. 2013. (Link) Furthermore, it is weakened and thereby not able to survive in case of slippage. We have also been working with the Odor Free chassis E.coli YYC912, which is a modified strain, not able to produce indole. This strain is non-pathogen as well. Source: Genportal, 2006. (Link) Our parts, both basic parts and devices are all taken from risk group 1 organisms and therefor do not contain nor mimic any virulence factors. This would be indicative of a very low hazardousness of our system. On the other hand, we have a self-designed protein and the safety of this brick might need to be considered. To avoid toxicity, we have shuffled the amino acids until the obtained sequence didn’t resemble any known toxin or other disease causing protein. We have also assayed the toxicity by feeding C. elegans bacteria producing OneProt (For more information see our results page).

Probability

When analyzing the probability, it is important to consider that there will always be an element of uncertainty in the results. The completion of our project implies the release of GMO to the environment. Even though our GMO will in several ways be weakened, the environmental effect of this release cannot be completely foreseen.

Risk

Our final product would include a group of cellulases, this could mean that there would be a remote risk that, in case of slippage, our bacteria could start to, uncontrollably, degrade cellulose into glucose for satisfying its own metabolic requirements. In this sense could these bacteria potentially become a threat for crops and other plants/trees. To manage this, our idea is to have the cellulases regulated by an inducible promoter, which will prevent the production of cellulase in the absence of the inducer. In a worst-case scenario could this promoter mutate to become constitutive active and thereby produce cellulase. Even if this was the case, would other safety mechanisms still be active, such as the kill switch and the general low environmental stability of E.coli K12. The probability of all these factors randomly mutating/ failing at the same time is almost negligible. We can analyze the risk of this event by using a risk matrix:

As for the risk for the safety and health to the general public, it is of great concern to avoid the spread of antibiotic resistance. All our constructs are made on antibiotic-resistant bacteria, which could, potentially, transfer resistance genes to other bacteria, in case of slippage. This would contribute to the increasing difficulty in fighting so far controlled infections. To avoid this, we thought that in a future these genes could be transferred into a plasmid developed in our university, which contains the proteins needed to make ribosomes and use E. coli knocked down for these genes. In this way is the bacteria completely dependent of the plasmid in order to survive, which can be used as an alternative method of selection.

Dual use

If the product was to be mis-used by individuals, groups or countries, could they potentially use this bacterium to induce the right combination of mutations, in order to get a plant-destruction weapon. We evaluate that the risk involved in the mis-use of our project is actually smaller than the mis-use of the cellulase biobrick in itself (because of the killing switch, need of mutating the promoter, etc.)

The mis-use of our protein might be aimed at mutating the protein to make it harmful. We consider, though, that if the aim is to create a harmful protein, there are other easier ways, such as starting with a pathogenic protein or simply designing a protein.

The best way to fight dual use, is to try to prevent it, by taking biosecurity measures in consideration, like limited access to laboratories and tracking of orders of gene synthesis.

Risk perspection: including others

It is our conviction, that a good synthetic biologist (and scientist) is the one that, besides evaluating the safety of his projects, include the general public into the discussion. Public opinion has an enormous effect on the feasibility of a project to succeed, both because the acceptance of the general public can make it easier to receive funding, but also because of the valuable feedback that can come as a result of the interaction between the general public and the synthetic biologist. Therefore it is important to communicate effectively and considerate, what might perceived as a risk factor. In our case, is bacteria and GMOs often considered as hazardous, and not as a food resource. The fact many people are not familiar with bacteria and GMO, could make the risk perception very high. To cope with this issue, we made our interactive video adventure, as an attempt to share the message, inform the general public and, hopefully, reduce the risk perception of our project.

All in all we believe that, even though there could potentially be some risks related to our project, it is safe enough to continue with our project, especially in the light of the potential and much more probable benefits.