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User:L7ukas
From 2010.igem.org
David Owen, John Mitchell, James Taylor, Patrick Olden, Chris Hooley
Rachael Blackburn,
Alasdair Morton, Wim Verleyen, Anne Smith, Lukas Ly, Sarah Shapiro, Johnathan Ward,
Fatemeh Salimi, Olivia Mendivil
Our multidisciplinary team is the first to hail from St Andrews University, consisting of biology students: Dave and Sarah, medical students: Rachael and Fatimeh, physicists: Alasdair and Patrick, computer scientist Jaunty, chemist Jim and biochemist Lukas. We are overseen by advisors Olivia, Anne, Wim, Chris and Michael.
The Problem
The St Andrews iGEM team plan is to do something useful with quorum sensing – the method by which bacteria make decisions in a cell density dependent manner. They do this by secreting autoinducer molecules, which diffuse back into the cells and regulate their own biosynthesis. Certain concentrations of autoinducer represent to a bacterium an amount of fellow-bacteria in the environment and the response is activation or deactivation of a set of genes. We are interested in the quorum sensing system of Vibrio cholerae, the bacterium understood to be responsible for the deadly diarrhoeal disease, cholera. Cholera is extremely rare in the developed world, but in areas with poor sanitation it affects people who drink unsafe water. Young children are the most at risk, and left untreated death can occur by dehydration. According to the WHO, cholera kills between 100,000 and 120,000 people every year. Efforts have been made towards an effective cholera vaccine suitable for young children, but they have not yet been successful. It is now suggested that synthetic probiotic bacteria could be a safe and economical way to confer resistance to cholera.
Quorum Sensing in Vibrio cholerae
Most cholera cells are killed off by stomach acid, but those that remain alive attach to the gut wall and multiply. At this low cell density, autoinducer concentration is low, and virulence factors are expressed. Once high cell density is reached, enough toxin is present to cause severe diarrhoea. At this point, the autoinducer concentration is high, and virulence factors are repressed. The now avirulent V. Cholerae detach from the gut wall and are flushed out of the body to infect a new host. Our idea is to synthesise Escherichia coli bacteria that will use this ingenious mechanism to communicate with Vibrio cholerae. Our engineered Escherichia coli will harmlessly colonise the gut, and in large numbers secrete the cholera autoinducer, CAI-1. This will cause an immediate high autoinducer concentration to be detected by incoming Vibrio cholerae cells which then become avirulent and harmlessly pass out of the body.
Our Plan
The wet work will focus on two challenges. The first being to add new functionality to the signalling parts present in the registry by re-engineering the existing
