The gene encoding an enzyme from a firefly, discovered at the Sorocaba campus of the Federal University of São Carlos (UFSCar) in Brazil, has given rise to a biosensor capable of detecting pH changes in mammalian cells—which could be useful, for example, in studying diseases and assessing the toxicity of a drug candidate.

The luciferase from the species Amydetes vivianii changes color from bluish-green to yellow and red as acidity decreases in fibroblasts, the most common cell type in connective tissue. It does so with great intensity and stability, something that had not been achieved with other luciferases tested by the research group.

The work is published in the journal Biosensors.