Team:Rheda Bielefeld/Biosafety



Before we dive into the deeper reasons of writing this abstract, we should explain what biosafety really is. In the paper "Safety, security, and serving the public interest in synthetic biology", Gronvall defines the term of biosafety: "Biosafety involves the safe handling and containment of infectious microorganisms and hazardous biological materials, and biosecurity pertains to the threats posed to human and animal health, the environment, and the economy by deliberate misuse or release of microbiological agents and toxins." (Gronvall, 2018)


Whitford et al. Journal of Biological Engineering (2018)

Why is biosafety so important in synthetic biology, especially in a competition like iGEM?

In synthetic biology the organisms, e.g. Escherichia Coli (E. coli), are genetically modified to produce or dismantle various things. But if only one genetically modified organism escapes the laboratory or reaches the environment, it can harm the outer nature and the humans. With safety measures including a kill switch or making them dependent on one substance they can't produce all by themselves, but are needed for their survival, it is possible to contain them in a laboratory setting and even if an organism leaves the labratory, it can´t do harm to the environment.

For an example, we can use our project. In our project, we used PCR-based methods to break the pollen´s exine and get their DNA. For that, we want to use E. coli by implementing an enzyme that dismantles cellulose and pectin, which the plant cell wall consists of. And in this way, an altered E. coli bacterium has the ability to dismantle cellulose and pectine, and with those abilities, it could bring great destruction to the environment because the cell wall of green plants and many algae are made out of cellulose and pectine.
Therefore we want to use a kill switch which for example releases a toxin and thus killing them. A different way would be making them dependent from a substance which they usually could produce by themselves but was cut out to prevent them from producing it and so making them dependent on this substance because they need it for their basic functions.

What is a kill switch ?

Basically, it works like an if & else switch.
If an activator, which is defined in the kill switch, like ultraviolet hits the bacteria, the kill switch is being activated and destroys the bacteria from the inside. As explained in the previous paragraph, the kill switch is there to prevent an outbreak and there are many ways to use a kill switch. One example is a kill switch by Team Wageningen UR 2014 ([1]), which has two toxins called Kid and Zeta and two antitoxins called Kis and Epsilon against those toxins. But the toxin and its antitoxin are on separate plasmids and so created an interdependent system. If the production of only one antigen, which needs a specific substance to be produced, stops the cell will die or one plasmid gets transferred to a wildtype cell, the antitoxin for the toxin on the plasmid is not present, thus killing the recipient.