Novel living system recreates predator-prey interaction

Using fluorescent microscopy, researchers document the predator-prey interaction. The predator cells, shown in green, have caused a prey cell, shown in red, to commit suicide. The elongation and separation of... Click here for more information.

DURHAM, N.C. – The hunter-versus-hunted phenomenon exemplified by a pack of lionesses chasing down a lonely gazelle has been recreated in a Petri dish with lowly bacteria.

Working with colleagues at Caltech, Stanford and the Howard Hughes Medical Institute, a Duke University bioengineer has developed a living system using genetically altered bacteria that he believes can provide new insights into how the population levels of prey influence the levels of predators, and vice-versa.

The Duke experiment is an example of a synthetic gene circuit, where researchers load new "programming" into bacteria to make them perform new functions. Such re-programmed bacteria could see a wide variety of applications in medicine, environmental cleanup and biocomputing. In this particular Duke study, researchers rewrote the software of the common bacteria Escherichia coli (E. coli.) to form a mutually dependent living circuit of predator and prey.

The bacterial predators don't actually eat the prey, however. 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 Lingchong You, assistant professor of biomedical engineering at Duke’s Pratt School of Engineering and member of Duke’s Institute for Genome Sciences and Policy. “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 results of You’s study appear April 15 in the journal Molecular Systems Biology. The research was supported by National Institutes of Health, the Defense Advanced Research Projects Agency, the Howard Hughes Medical Institute, and the David and Lucile Packard Foundation.

This field of study, known as synthetic biology, emerged on the scientific scene around 2000, and many of the systems created since have involved the reprogramming of single bacteria. The current circuit is unique in that two different populations of reprogrammed bacteria live in the same ecosystem and are dependent on each other for survival.