Microbe ‘kill switch’ developed for safer use of engineered bacteria

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Many research teams are developing genetically modified bacteria that could one day travel around parts of the human body, diagnosing and even treating infection. The bugs could also be used to monitor toxins in rivers or to improve crop fertilization.

However, before such bacteria can be safely let loose, scientists will need to find a way to prevent them from escaping into the wider environment, where they might grow and cause harm.

To this end, researchers at MIT, the Broad Institute of MIT and Harvard, and the Wyss Institute at Harvard University have developed safeguards in the form of two so-called “kill switches,” which can cause the synthetic bacteria to die without the presence of certain chemicals.

In a paper published in the journal Nature Chemical Biology, the researchers describe their two kill switches, which they call “Deadman” and “Passcode.”

The Deadman switch, for example, is part of a bacterial strain that needs an external chemical to prevent a continuously expressed toxin from killing the cell.

The switch was motivated by the so-called deadman brakes on old trains, which required a conductor to be in constant contact with the handle or pedal in order for the vehicle to move forwards, says James Collins, the Termeer Professor of Medical Engineering and Science in MIT’s Department of Biological Engineering and Institute for Medical Engineering and Science (IMES), who led the research.

Read full, original post: “Kill switches” shut down engineered bacteria