iGEM Tokyo Tech 2011 Team

Overview: Cool down in summer with our Rock-Paper-Scissors Game

When summer comes it brings vacations, so students have plenty time to have fun. But summer means hot weather! In light of these circumstances, we designed a game that can be played between E.coli and humans. The winner of the game can get refreshing prizes! Dear students, let us introduce you to the first human-bacteria Rock-Paper-Scissors game! Win and get a rain shower and a “urea cooler”!

Rock-Paper-Scissors (RPS) Game

So, how to play RPS with a handless bacteria? Instead of hands, we use different signaling molecules corresponding either to rock, paper or scissors. In our set of six signaling molecules, humans use IPTG, aTc and salicylate, and E. coli uses 3O-C6-HSL, 3O-C12-HSL and AI-2. In each case, these signaling molecules correspond to rock, paper and scissors respectively.

The next step is to design a way to know who wins the RPS game. That is when the E. coli judge team comes in! Each judge has an AND-gate promoter which produces a single output based on two inputs, human side and E.coli side signaling molecules. Since we want the output to be visible, we use either GFP, RFP or CFP to indicate whether humans win, lose or it is a tie, respectively.

Lastly, we need to make sure E. coli follows the rules of the game by synthetizing only one signaling molecule every time it plays. Importantly, we have to design the opponent E. coli to be able to choose its signal randomly for a fair game, because E. coli will continue to lose if it always produces the same signaling molecule. In a view of these needs, we designed three randomizers that satisfy the conditions for the game:Single Colony Isolation, Survival of One Strain and Conditional Knockout. (see more...)

Make it Rain

Playing RPS with E. coli during summer was fun, but, even if humans won, joy did not last long since we soon returned to complaining about the hot weather. As a prize for humans who win in our RPS game, we designed an E. coli that can make it rain, making the hot summer more fun and refreshing (let alone applications in agriculture). To make it rain, we constructed an isoprene synthetizing E. coli. Photo-oxidized isoprene acts as a condensation nucleus(Colin D. O‘Dowd et al., 2002, Nature), which might cause rain, even in very low concentrations. (see more...)

Urea Coolers

Coolers can be made by adding urea to water, since dissolving urea in water is an endothermic reaction (-57.8 cal/g). We can make E.coli synthetize urea just by introducing a gene encoding arginase!

To analyze how we obtain even more urea from our E. coli, we used elementary flux analysis (Schusteet al. 2000) to identify metabolic routes that are both stoichiometrically and thermodynamically feasible for a group of enzymes. Making use of it we can tell which substrates and pathways are the best for obtaining more urea.(see more...)

Human Practice

We love Synthetic Biology, and to share our passion with other people, we did educational activities as part of our human practices. We would like to spread the word about what is made and aimed by synthetic biology and iGEM. To do so, we created the “iGEM Card Game” and several posters. We also measured our impact through a survey. (see more...)