Team:University of Sheffield / Late BrSt

Goals
The (relatively ambitious) aim was initially to engineer a biological machine that will sense microbial contamination of drinking water using quorum sensing. The organism would initially be designed to sense a wide range of pathogens – the coliform bacterias, Escherichia coli, Shigella, Campylobacter, Salmonella enteritidis, Helicobacter sp., Vibrio cholera, Mycobacterium avium and the protozoans Giardia lamblia, Cryptosporidium sp., Cyclospora sp. and Toxoplasma sp. These cause a range of serious diseases such as dysentery, typhoid, cholera and many gastrointestinal infections.

Method Brainsorming
Two organisms would be modified for quorum sensing purposes, Escherichia coli and Bacillus subtilis. They represent gram negative and gram positive bacteria respectively. The choice of the class of bacteria to be used by the team will be based on suitability for expression of particular genes. The genes encoding receptor would be transferred from the target pathogenic organism to the sensing bacterium. As a result sensing bacterium would express this receptor and be able to bind the signaling molecule produced by the target organism. Subsequently, this binding would in turn trigger designated pathways within the sensing bacterium. These would lead to expression of Green Fluorescent Protein. Therefore, when pathogen is present in water, the sensing bacteria would start to fluoresce.

The design of biological pathways and circuits is going to be achieved applying mathematical tools. The intention is to invent a universal chassis with an easily exchangeable sensor part for different pathogens. It should enable straightforward switch of any intended gene and construction of various sensing biological machines on the basis of the Sheffield team design. Moreover, this way by standardizing new sets of genes the team would contribute to the Registry of Standard Biological Parts.