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’.

Auto-regulated production of 1,4-BDO

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

Various results from our study show that when the auto-regulatory device is introduced into biological machine, the Escherichia coli cell, it can operate the system as we intended. In application section, we have explained the bio-indigo production system which is operated in accordance with change in AHL concentration.

Because the binary signal generator produces one out of two proteins with their genes in opposite orientation, we can apply the device to manage two competing pathways. If the resource to operate the pathway we want is a critical factor for cell survival, our device will be helpful for biological machine. By arranging two pathways, one expressing resource protein and the other expressing target protein, in different orientation, we can have auto-regulated pathway which is operated by binary signal generator.

The specific example is operating the 1,4-BDO pathway in E.coli. Because the enzymes participating in the 1,4-BDO pathway requires high NADH potential, the critical factor to cell survival, simple cloning of the enzymes may bring harmful effect to the cells. By designing 1,4-BDO enzymes and NADH detector(or redox potential detector) at each end of binary signal generator, we can produce 1,4-BDO effectively without harmful effect to growth of Escherichia coli cells.

All iGEM Team KAIST members spent the hottest summer this year. We have learned various experimental techniques, background knowledge and also about “Synthetic biology”. Because none of us had experienced synthetic biology, it took some time to make our theme to contain true synthetic biological meaning. Nevertheless, passionate members of KAIST team were able to reach their own meaning of synthetic biology.

Because we made great efforts to get our concept, we do not want it to fade out after iGEM competition. We hope we can help following-up iGEM teams from KAIST, other teams in Korea, or even any other teams in the World. And we believe our insight to synthetic biology will make our studies more productive and creative, even after iGEM.

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Team:KAIST Korea/Project Future

From 2012.igem.org

Bacteri-Guard

Auto-regulated production of 1,4-BDO