Team:Tokyo Tech




This is iGEM Tokyo_Tech 2014 Wiki!

Project Planning

Through interaction with the general public people in our project planning stage, we realized that we do not know much about economics in spite of our study for biology.

For our future innovation based on knowledge of economics, we thought of creating an educational tool of economics by using E. coli and BioBrick, which are familiar for iGEMers.

Fig. 1-1-1. Our members discussing about the project with the visitor

Project Overview

Like the exchange of money and products in the real economy, we designed three types of E.coli (Bank, Company, and Customer) which exchange Product and Money in the tool’s economic system. Product and Money were represented by 3OC12HSL and C4HSL, the signaling molecules of the quorum sensing, respectively.  In the final step of our wet experiments, we achieved the mutualism of Company and Customer in test tubes.


Fig. 1-1-2. Relationship among three types of E. coli

Fig. 1-1-3. The growth dependency of Prhl and Plux promoters

From the simulation before wet experiments, we noticed that the strength of the two signaling-molecule dependent promoters, Prhl and Plux, need to be close in order to promote Company and Customer’s growth. However, in our first step of the wet experiments, Prhl promoter showed far less fluorescence intensity than Plux promoter.

(Go to Plux and Prhl reporter assay page)

Thus, we improved the promoters fluorescence intensity by recombining regulatory-protein binding sites. Our Prhl(RL) promoter (K1529300), which has the highest S/N ratio and much higher activity than native Prhl promoter, was used for the following experiments. 



Fig. 1-1-4. Our improved Prhl promoter


(Go to Prhl reporter assay page)


We then demonstrated the mutualism between Company and Customer through modeling and wet-experiments.  By measuring the fluorescence intensity of GFP with flow cytometer, the co-culture of the Company and Customer shows that company and customer promoted the growth of each other (Fig. 1-1-5).

Fig. 1-1-5. Company and Customer co-culture assay

We then introduced Bank to our educational tool.  In the real economy, thousands of Company-Customer pairs exist in a market.  In the emulation of such situation, a pair of Company-Customer is allowed to occupy just small scale.  Even though a large scale economy achieved growth of both Company and Customer (Fig. 1-1-6-A), our modeling results for mutualism in a small scale showed that both company and customer will die at a low initial cell concentration (Fig 1-1-6-B.). In order to solve this problem, we introduced E. coli which functions as a central bank. This Bank E. coli to the small-scale economy recovers growth of both Company and Customer (Fig 1-1-6-C.).

Fig. 1-1-6. Bank regulates the money supply

In further dense interaction with entrepreneurs, we were pointed out that economic wave should be integrated into our system to make it more realistic. We thus performed a modeling on economic wave to see how it works. Although Economic wave can destroy mutualism system (Fig1-1-8 A,B, D,E), bank allows the system to keep a coexistence relationship (Fig1-1-8 C and F) even when there is a change in the amount of money supply in the market(Fig1-1-8.).

Fig. 1-1-7. Our teammates consulting the professionals at the workshop MUSE TALK
Fig. 1-1-8. Economic wave

Project Evaluation


Finally, the evaluation of our educational tool using E. coli and BioBrick showed that our project is highly effective for students majoring in biology to understand economics (Fig. 1-1-9).

Fig. 1-1-9. Effects of our presentation

Future Works

Our big dream is to allow E. coli to obtain "sociability". By using more signaling molecules and other types of materials, we are eager to simulate the whole human society by building a larger network in test tubes. Moreover, our achievements can be applied to multistage substance producing. Microbial consortia can perform even more complicated tasks through the division of labor by using the mutuality. For such construction of consortia, the improved Prhl promoter broadens quorum sensing, and updates the previous cell-cell communication systems greatly.