A variety of the yeast used in baking and brewing has been genetically modified to "sniff out" explosives, and may one day help detect a range of dangerous substances, including sarin gas.

The biosensor was developed by Professor Danny Dhanasekaran and his colleagues at Philadelphia's Temple University School of Medicine. They used genetic engineering techniques to install olfactory signalling machinery - the system that detects and identifies odours - from rats into yeast cells. The surface of the yeast cells became sensitive to the smell of dinitrotoluene (DNT), a residue from the manufacture of the explosive TNT.