What is biosafety

From 1953 when Watson and Crick revealed the DNA structure, the knowledge on Molecular Biology has been growing ceaselessly. The most innovative subjects in Molecular Biology are Synthetic Biology and Systems Biology, and they are intertwined. The first one uses engineering tools to build biologic systems and the second one uses them to get to an understanding of already existing systems. We will be acquiring a huge amount of knowledge from these disciplines in the next years. From the creation of new and more effective vaccines to the degradation of pollution, the promises are numerous and hopeful. According to the ABSA (American Biological Safety Association):

“The concept of Biological Safety (or biosafety) has paralleled the development of the science of Microbiology and its extension into new and related areas including tissue culture, recombinant DNA, animal studies, Molecular Biology, Synthetic Biology, and Biotechnology. The knowledge and skill gained by microbiologists necessary to isolate, manipulate, and propagate pathogenic microorganisms required parallel development of containment principles, facility design, and practices and procedures to prevent occupational infections in the workplace or release of the organisms to the environment.” ^[1]

As time goes by, we will need safer conditions in biotechnology laboratories in order to avoid any kind of hazard. Here you can find some interesting issues on safety and a short description of the Prh system, which has been taken from the pathogenic bacterium, Ralstonia Solanacearum.

Prh System

Symptoms of southern bacterial wilt in tomato caused by Ralstonia solanacearum

This system comprises four parts. A protein known as PrhA in the outer membrane, which detects something (still unknown) on the plant cell wall; PrhR is in the inner membrane and can be activated by PrhA, which, in time activates a diffusive protein called PrhI; and finally a promoter activated by PrhI, PprhJ. You can read much more about this here. These parts have been extracted from the plant pathogenic bacterium Ralstonia Solanacearum, which causes important diseases in many plants. In this bacterium, the Prh system is used to initialize the infection of the plant through the regulon hrp. Once this system is activated, the plant starts to transcribe the genes which encode pili and type III secretion.

At the beginning of the summer we thought we could extract the whole system from this bacterium using PCR but soon we realized that this was going to cause many problems because of the dangerousness of Ralstonia. We needed special conditions in the laboratory to work with that bacterium and that could be rather problematic. Mr Gen gave us the solution. We had the whole Prh system synthesized. That is one of the advantages of synthetic biology: in many cases you do not have to work directly with organisms that have the bioparts that you are interested in; you can get those parts either by synthesizing them or, if they are already in the main registry, you can simply take them from it.

Finally we had not time enough to assembly the whole Prh circuit, but we used part of it: we built a new protein mixing the external domain taken from PrhA (which is the responsible part of detecting plant cell walls) and the internal domain taken from FecA, which allows this protein transducing a signal through the Fec system. Anyway, we have submitted the whole Prh system to the registry and we are planning to use it in future projects. It is important to notice that the Prh system is completely innocuos when outside Ralstonia Solanacearum.

Some FAQ about biosafety

1. Does your project require the exposure or release of the engineered organism to people or the environment (e.g. as medicine, for bioremediation)?

   Not for the present. This year we only want to make a test to demonstrate that the main idea of our project is feasible. Maybe in a future we will decide to carry on with this project in order to find an useful application, for example to crowd a big amount of bacteria around a tumor cell to destroy it through the release of a drug.

2. Could your device, when working properly, represent a hazard to people or the environment?

   Not at all. The strain of E. coli we are using in our lab is completely inoffensive, and so are the devices we have built through synthetic biology.

3. Is your engineered organism infectious? Does it produce a toxic product? Does it interfere with human physiology or the environment?

   Not at all. Our E. coli cells are able to attach vegetal cells when gathered in large numbers but they do not do much more than that. They can release a innocuous chemoattracctant substance which is an amino acid (aspartate), so it is harmless. It does not interfere in any way with the environment or human physiology. And the most important thing, the strain of E. coli that we are using (K12) is not able to live out of lab conditions.

4. What would happen if one or several bioparts change their function or stop working as intended (e.g. through mutation)? How would the whole device or system change its properties and what unintended effects would result thereof?

   If FecA-PrhA changed its structure it might recognize other shapes different from the wild type. For example a mammal cell, but this is extremely unlikely. In any case, we have no idea how our E. coli cells could become pathogenic just by mutation. But something actually happened in our project by mutation: our E. coli strain lost its motility and it could not show chomotaxis behaviour. Thankfully we realised that and used other E. coli strain.

5. What unintended effects could you foresee after your engineered organism is released to the environment?

   Probably nothing. Firstly, because the E. coli we are using (as we said before) cannot live outside the laboratory. Secondly, because if we were using another bacterium which could live outside the laboratory, the effects of the system we have build could not be detected and would cause no harm at all.

6. Do any of the new BioBrick parts that you made this year raise any safety issues?

   They all are completely safe. There are no parts contains toxic or dangerous substances.

7. Is there a local biosafety group, committee, or review board at your institution?

   No, so we have taken the safety measures that the Microbiology department uses to follow.

References

1. American Biological Safety Association. Biosafety