Cited research: Nature Chem. Biol. doi:10.1038/nchembio.369 (2010)

Researchers have engineered a strain of the bacterium Escherichia coli to migrate towards and degrade atrazine, a common herbicide and environmental contaminant.

Justin Gallivan and his colleagues at Emory University in Atlanta, Georgia, have developed an atrazine-sensitive synthetic riboswitch — an RNA molecule that regulates gene expression. They inserted the riboswitch into E. coli, where it controls a motility protein, causing the bacteria to move towards atrazine.

The researchers next added a gene for an enzyme that breaks down atrazine. They show that in a Petri dish containing atrazine, engineered cells move outwards, destroying atrazine in their path. As herbicide levels drop, cells eventually slow down and stop. The team suggests that a similar approach could be used to reprogram bacteria for other tasks. C.L.