Project Overview

Bacterial Relay Race

In our project we aim to create a cell-to-cell communication system that allows the propagation of a multi-task message with the capability of being reset. To achieve this, the system will include a reengineered conjugation system, a time-delay genetic circuit and a self-destructive plasmid. This system could be the basis for creating a long distance biosensor and/or be applied in reducing antibiotic resistance of bacteria.

Project description

Our project is Bacterial Relay Race. As our team logo and the animation below show we want to build an improved cell to cell communication system. We choose cell to cell communication as subject because of its great importance. Cell to cell communication systems are important because most applications or tasks we set to our synthetic biological systems are generally completed by a population of cells, not a single cell. Gaining new insights at cell to cell communication and designing manageable cell to cell communication systems will provide us a scale of new possibilities. Manageable cell to cell communication systems could have applications in different fields like therapeutic application or fermentation technology applications. We want to construct an E.coli strain which is capable of passing a GFP signal through conjugation to other E.coli cells only once. Communication appears population wide. Our work builds on projects of previous iGEM teams from Berkeley UC and Peking University.

Our project is made up of three modules:

1) Conjugation

We want to build a cell to cell communication system in which communication is based on conjugation. Through conjugation a GFP message is passed to other bacteria in the culture.

2) Self Destructive Plasmid (SDP)

The plasmid contains a GFP message, inducible endonuclease gene and restriction site of this endonuclease. The plasmid is able to degrade itself after receiving the destructing signal.

3) Delay device

It is important that there is a time delay between the moment of passing the SDP and the destructing of it. If the SDP is degraded to fast after conjugation, the degradation of the SDP will not be detected. Therefore we construct a device in this system which delays expression of the endonuclease.

Some potential applications for this project are

1. Grasping of bacterial communication - the communication between bacteria using DNA can advance through bacterial networks, and in this sense our project would allow to send multiple messages in a single DNA, thereby to better understand those bacterial communication networks.
2. Understanding of bacterial antibiotic resistance - these days, bacterial infections are often treated with antibiotics. Unfortunately, bacteria have the tendancy to pass antibiotic resistance to other bacteria through the process of [http://en.wikipedia.org/wiki/Bacterial_conjugation conjugation], thus making the antibiotics useless. Using our project, it might be possible for future researchers to better understand the mechanism by which antibiotic resistance passes among bacterial colonies, and perhaps even inhibit it.
3. To test one condition and return to the original state without killing the cell or changing any of its previous genetic and physiological characteristics
4. To generate a pulse in the expression of a certain gene
5. To control the amplitude of the pulse created by the plasmid