Nutrient-Control for GM Bacteria

Genetically modified bacteria that don’t survive unless given an unnatural amino acid could serve as a new control measure to protect wild organisms and ecosystems against accidental release. 

Jan 20, 2016
Jef Akst

Colorized scanning electron micrograph of E. coliFLICKR, NIAIDGenetic and CRISPR-based kill switches have made headlines recently, as researchers engineer ways to prevent organisms built or modified in the lab from escaping to the wild. Now, Andrew Ellington of the University of Texas at Austin and his colleagues propose a new solution: limit the growth of a genetically modified (GM) E. coli strain when the environment lacks unnatural, or noncanonical, animal acids (NCAAs).

NCAAs have been used to expand or alter the genetic code of various organisms. But by reengineering the antibiotic resistance gene TEM-1 β-lactamase to only produce a protein in the presence of an NCAA, Ellington and his team created a bacterium that can be killed should it ever escape the lab. When provided with the necessary NCAA, however, the E. coli can live for hundreds of generations.

“We need to have biosafety features that allow you to ensure that when you’ve made something it’s not going to escape from the lab, or if it does it won’t be able to prosper,” Ellington told New Scientist. “In the presence of antibiotics and the absence of the [artificial] amino acid, there’s very little way for our circuitry to leave the lab.” The researchers published their results this week (January 18) in Nature Chemical Biology.