Team:Chiba/Project

E.coli Time Manager Since 2008

Introduction

30分後、1時間後、12時間後…、セットした時間に自動的にスイッチが入る「タイマー」は、電子機器に不可欠な基本機能です。生物には薬をつくったり、有害物質を分解したりといった様々な機能があります。この生物の優れた機能も、自由にタイマー起動できるようにしたい！　ということで、私たちを含む世界中のチームが、様々なタイマー作りにしのぎを削っています！

We iGEM CHIBA are making a device that consecutively activates various activity of organisms. 30min, 1hour, half a day,,,The TIMER that switches on at preset time is essential and fundamental function for our life. Organisms can make some medicines, or decompose harmful materials. To control regulation these favorable function freely,

Project Design

時間を扱った2008年のMelbourneや、2007・2008年のParisチーム、2008年のNYMUチームのプロジェクトでは、細胞集団の振る舞いを同時にするためにシンクロシステムが必要でした。そこで千葉はシンクロシステムを使わずに細胞集団をコントロールできるシステムを作ろうと考えました。ここで使うのが細胞間のSignaling Systemです。

Signaling System

In this project, we use acylated homoserine lactones (AHLs), signaling molecules used for [http://en.wikipedia.org/wiki/Quorum_sensing quorum sensing] in gram negative bacteria. Senders express LuxI or similar enzymes, which catalyze the production of AHLs, under the control of a constitutive (Tet) promoter. Each cell thus generates AHL more or less at a constant rate. AHL can freely permeate cell membranes and are detected by neighboring cells. Receivers constitutively express LuxR proteins (or a similar ortholog), the protein that detects AHL concentrations. When AHLs bind LuxR proteins, the AHL-LuxR complex activates the Lux promoter. The threshold [AHL] at which switching occurs is determined by the affinity of AHL for the particulr LuxR ortholog. (more about quorum sensing)

Constructing A Delay Switch, Multiple Ways Since 2008

まず私たちは、Delayスイッチを作ろうとしました。 これは2008年のプロジェクト内容の続きにあたります。

In principle, there are three ways to delay the activation of chemical communications;

1. Silencing the Speakers: Rate of signal accumulation down-regulated, for instance, by slowing down the signal generators.
2. Desensitize Receivers: Switching threshold elevated, for instance, by using insensitive receiver/ reporter systems.
3. Partial Blocking: Decreasing the by chewing the signal up.

Inter-species communications!

We decided to go for the strategy inspired by Japanese-classic experience; Whenever we speak to somebody in English, we often experience a certain delay in activating the communication. We though this is exactly what we pursued in. See Exp #4. Same applies to the reverse, too. When somebody speaks to us, we definitely need some time (sometime infinite) to get activated. This is all in spite that he/ she was loud and clear enough. The less affinity (perception) we have to English, the longer we need to activate them.See exp #5.

-> Get more information about a Delay Switch!

Constructing A Flow of Activation

Conclusions