Bacteri-Guard

As our future plan, we came up with this system, Bacteri-Guard. Let’s see how it works.

In this system, a gene expressing pollutant sensor protein is initially generated due to its promoter orientation. When pollutant sensor detects pollutants, it will initiate the expression of integrase. Then, integrase will recognize and invert the orientation of promoter sequence. Now, scavenger proteins will be expressed and start to remove pollutants. Meanwhile, GFP will be expressed as well to let us know that pollutants are being degraded. In the end, exisionase will be expressed, which will in turn retrieve the initial orientation of promoter.

This is just a ‘concept’ up to this point. However, we still view our concept valuable since these little sensors and scavengers would work as guardians of the environment. Bacteri-Guard has some advantages over conventional sensors. When ordinary sensors notice toxic compounds or pollutants, scavengers are expressed but their expression rate does not vary while the amount of pollutants varies. This may cause stress and eventually be harmful to cells. However, Bacteri-Guard is capable of adjusting expression of scavenger molecules and turning them on or off. This is the major excellence of our module and through this we can avoid unwanted stress toward cells. To simply put, with our module, we can take care of the environment and relieve the stress of host cell in automatic manner. Allowing natural recovery, this is the beauty of our module and ‘Bacteri-Guard’.

In mechanical engineering, various devices designed to operate the machine. Throughout our conceptual and applicable designs, we have tried to demonstrate the possibility of reproducing the scheme of mechanical engineering in “Biological Machine”.

Various result from our study shows that when the biological device, binary signal generator, is introduced into biological machine, the Escherichia coli cell, it can operate the system according to our intention. In application section, we have explained the bio-indigo production system which is operated in an accordance with change in AHL concentration.

Because the binary signal generator produce one out of two proteins with different orientation, we can apply the device to manage two pathways that are competing. If the resource to operate the pathway producing the protein we want is critical factor for cell survival, we can apply our device into biological machine. Arranging the genes for resource protein generating pathway and the target pathway genes in different orientation, we can make auto-regulated pathway that is operated by binary signal generator.

The specific example can be operating the 1,4-BDO pathway in E.coli. Because the enzymes participating in the 1,4-BDO pathway requires high NADH potential which is critical to cell survival, simple cloning of the enzymes can give harmful effect to the cells. So that, designing 1,4-BDO enzymes and NADH detector(or redox potential detector) at the both end of the binary signal generator, we can produce 1,4-BDO effectively not giving harmful effect to growth of Escherichia coli cells.

All of iGEM Team KAIST members spent the most hottest summer this year. We have learned about various experimental techniques, background knowledge and also about “Synthetic biology”. Because none of us had experienced about synthetic biology, we spent some time to make our topic to contain the synthetic biological meaning. However, passionate members of KAIST team were able to make the synthetic biology as our own knowledge thinking and thinking repeatedly.

Because we got our knowledge with constant efforts, we do not want our knowledge to fade out with completion of iGEM competition. We hope we can help following-up iGEM teams from KAIST, or in Korea even any countries in the World. And we think the synthetic biological insight will make our studies after iGEM to be more productive and creative.

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Team:KAIST Korea/Project Future

From 2012.igem.org

Bacteri-Guard