Team:UT-Tokyo/Sudoku abstract
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Sudoku
Abstract Construct Lab note Result
Abstract
We're trying to make E.coli solve Sudoku puzzle. Human and Computers can solve Sudoku, of course. But E.coli, which is lower animal, solves sudoku in our project. It is very very interesting!
What is Sudoku?
Sudoku is a puzzle game with the objective of filling a 9x9 grid of cells with the numbers 1~9 without entering the same number in a column, row or “block (see figure).” A player is given a grid in which some of the cells are filled in from the beginning and must complete filling in the grid by entering the remaining numbers.
Solution unique to the microbe: parallel computing
When we solve Sudoku, either manually or by using a calculator, we usually enter random numbers in the grid one by one and look for the correct combination by trial-and-error. On the other hand, our E. coli are each capable of independently filling in the boxes simultaneously. In other words, our E. coli perform parallel computing.
How to solve Sudoku?
Instead of the traditional 9x9 grid of cells, we use E. coli possessing information of its location within the grid, in a liquid mixture.
At the beginning, most of the bacteria are not designated a number while some of them are designated as an initial condition. Through undesignated bacteria receive information from their environment, they are designated a number, causing them to “differentiate” into a state in which they emit viruses possessing information of the bacterium’s location and number. These viruses in turn collectively compel other bacteria to be designated a particular number.
In such a system, each bacterium must be able to identify relevant information, retain this information, and finally amass this information to “differentiate” into a particular number. To realize this, we use DNA recombination caused by proper virus.
Differentiation model in prokaryote
E. coli in each box rearrange DNA and determine their numbers by receiving information about the number from other E. coli in the same row, column, and block. In other words, they change their states irreversibly from “the multi-output state” to “the uni-output state.”
We realize this by making a switch we named “4C3 leak switch,” using the leak of terminators. This switch turns on when three of four choices are transmitted, regardless of the order of transmission.
Information transmission by virus
To transmit information for proper E. coli, we use RNA phage named “signal virus.” Translation of the RNA transmitted from signal virus is controlled by antisense RNA characteristic to their location information.
This destination-restricted information diffusion can be a powerful tool for building bio-computer, which use the creature as the unit of calculation.
Reference
MS2 1. 2.
Safety issue
We use new parts which are not registered as BioBrick parts. We don't intend to execute experiment which affect the environment or human body. We do experiment in the laboratory which safety is maintained and recombinant E.coli and virus which include new parts are not taken out of the laboratory.