Duke University researchers, using genetically altered E. coli bacteria to form a mutually dependent living circuit of predator and prey, said their experiment is an example of a synthetic gene circuit, in which researchers load new "programming" into bacteria to make them perform new functions. They said such re-programmed bacteria could be used in a wide variety of applications in medicine, environmental cleanup and biocomputing.

The bacterial predators don't actually eat the prey. Instead, the two populations control each others' suicide rates.

"We created a synthetic ecosystem made up of two distinct populations of E. coli, each with its own specific set of programming and each with the ability to affect the existence of the other," said Assistant Professor Lingchong You. "This ecosystem is quite similar to the traditional predator-prey relationship seen in nature and may allow us to explore the dynamics of interacting populations in a predictable manner."

The study that included scientists from the California Institute of Technology, Stanford University and the Howard Hughes Medical Institute appears in the journal Molecular Systems Biology.