Bacteria collaborate to sense arsenic

Abstract

A method developed to allow rapid communication between bacterial cells across long distances enables the cells to detect arsenic collectively, and to report it as an oscillatory output. See Article p.39 The first synthetic biological oscillators, networks of transcriptional regulators designed to perform a single function, were developed just over a decade ago. Recently it became possible to synchronize a colony of such oscillators coupled through bacterial quorum sensing, but this was limited to short-range synchrony. Now, by combining two synergistic modes of communication — generation of hydrogen peroxide vapour and redox signalling — Jeff Hasty and colleagues have synchronized extremely large populations (around 50 million cells) of Escherichia coli bacteria distributed in quorum-sensing colonies, or biopixels, spread across centimetres. This array was used to build an LCD-like macroscopic clock capable of sensing the presence of arsenic through modulation of the oscillatory period. With further development, biopixel colonies of this type might form the basis of low-cost genetic biosensors capable of detecting heavy metals and pathogens.