We are always paying special care to the safety of our teammates and the people around. Thus we signed a document to keep in rules about the Safety in Laboratory, not only to protect ourselves but also help to keep a clean and healthy environment.

The model organism we used are harmless engineered strains of Escherichia coli. They are widely used in all kinds of laboratories around the world. We answered the questions about safety on the Safety Page from iGEM(https://2011.igem.org/Safety) as following:

• Q1: Would any of your project ideas raise safety issues in terms of:
  • researcher safety,
  • public safety, or
  • environmental safety?
• A: Our project is to use E. coli to bind to and transport target proteins in the media. No serious safety problem can be caused by the harmless engineering strains of Escherichia coli and we kept our promise and rules which ensure the safety during the whole process.
• Q2: Do any of the new BioBrick parts (or devices) that you made this year raise any safety issues?
• A: No potential safety issues.
• Q3:Is there a local biosafety group, committee, or review board at your institution?
• If yes, what does your local biosafety group think about your project?
• A:Our lab work is supervised by a safety group at the microbiology lab. Whenever reagents with safety concern is involved, for instance, ethidium bromide, at least one member in the group will watch us all the way to ensure no danger might be incurred during our operation. Besides, supervisors from Tsinghua University also scrutinized our bench work. During one routine check, they asked us a lot of questions on safety and praised us for the great caution and the excellent protection measures we took during our experiments.
• Q4: Do you have any other ideas how to deal with safety issues that could be useful for future iGEM competitions? How could parts, devices and systems be made even safer through biosafety engineering?
• A:The most invigorative way to inspire the teams to make up ways to deal with and improve the BioSafety is to establish a special prize in BioSafety, so that many teams could try their best to deal with the issues in BioSafety, like how to take experiments safely, how to build safe BioBricks and mostly how maintain the safe environment during our projects.
• Also to recognize that importance from the bottom of one's heart is the most effective approach for dealing with some issues. So if more education, announcement, lectures, courses and many other kinds of teaching methods can be carried out to draw attention on the safety, to let people keep this in mind, the Safety Issues could no longer be an issue but a common sense.
• All the staffs and students operating the infrastructures, devices and anything related with experiments are required to wear the gloves all the time while working. To keep these in rules and in case of any accidents we carried out a document to keep in line with.

Proposal on increased safety

iGEM always requires a handful of standard part plasmid backbone for parts submission. The current plasmid backbones takes economy and efficiency into consideration, but did not consider the safety issues. Any DNA sequence with potential harmful effects might thus diffuse into the environment and harm the public safety.

We thus propose poison and antidote system and restriction and mutation system.

Poison and Antidote

On the bacteria host genome and the plasmid, there are two pairs of "poison", suicide gene, and "antidote", the resistance gene.

P stands for "poison", or suicide gene. A stands for "antidote", or resistance gene. The two different colors indicate two different poison and antidote pairs.

Thus, the interdependence of the host cell and the plasmid is established. When the gene is in the environment, it cannot be spread further. Moreover, this also restricts mutations in both the host and the plasmid, as severe variations in gene structure will disrupt the function of either version of the "antidote", leading to lethality of the bacteria.

Restriction and Mutation

Restriction-modification system is originally a system used by E. coli to defend against viral infection. In our design, E. coli can express I-SceI endonuclease from its chromosome and the parts vector contains a mutated I-SceI site.

In its starting state, the site on the plasmid cannot be recognized by the endonuclease, allowing for the amplification of the vector in the bacteria strain. Nonetheless, when the vector is over-amplified due to nutrient-starvation or drug induction, the site became available to the restriction enzyme, causing a self-restrition of the vector copy number. When mutations began to accumulate in the plasmid, the site will tend to be transformed into active I-SceI site, causing the degradation of the mutated plasmid.

In this way, both the environment stress and the mutations in the plasmid will activate the restriction enzyme and limit the copy number of the vector, partially controlling spread of biobricks into the enviroment.

Our experiments

We successfully modified the universal biobrick vector pSB1C3 and inserted the ccdB expression cassette and the mutated I-SceI site into it. In this way, the vector part of our system is established.

When such plasmid and E. coli strains are required, the overall safety will be greatly increased.