Genetic switches that make bacteria self-destruct in response to specific signals could help to keep engineered microbes in check.

Microbes that have been genetically modified for industrial and other uses rely on the addition of certain nutrients to grow, but this makes it difficult to design organisms that can be contained in different environments. To overcome this, James Collins of the Massachusetts Institute of Technology in Cambridge and his colleagues designed gene circuits that act as 'kill switches' when they are introduced into the genome of the bacterium Escherichia coli. The switches block essential genes or induce lethal toxins when triggered by environmental chemicals.

Such kill switches can be customized to respond to different cues, the authors say.

Nature Chem. Biol. (2015)