Nature. Philip Ball. 12 Feb 04

Scientists have genetically engineered bacteria to ‘talk’ to each other in a new language. The achievement brings us one step closer to turning cells into tiny robots that we can control by flooding them with chemicals.

Bacteria already communicate with each other by sending out chemical signals. A cell might release a certain chemical in response to stress, for example, letting other cells nearby know they should prepare for some unpleasant environmental conditions. When the chemicals reach a high enough concentration, they switch on genes in neighbouring cells that change their behaviour.

But cells typically have a limited number of stimuli that provoke these chemical warnings, and a limited number of chemicals that they can use to communicate. James Liao and co-workers at the University of California, Los Angeles, wondered if they could [genetically modify] bacteria to talk using a different chemical.

They started by stitching a ‘module’ of control genes into the genome of Escherichia coli bacteria; these control genes can then switch on or off other genes naturally present in the bacteria.

This technique has been used before. For example, four years ago researchers at Princeton University in New Jersey added a gene module to E. coli cells that made them blink on and off like light bulbs; the genes did this by prompting the cells to make a light-emitting protein called GFP in regular spurts.

This new work is significant because it doesn’t simply create new “outputs”; in this case it develops new feedback loops, which in turn…

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As an aside, I can highly recommend Philip Ball’s excellent book Stories of the Invisible: A Guided Tour of Molecules