Bright luminescent yeast cells with light intensities similar to bacteria containing luciferase (LuxAB) were generated by providing saturating nontoxic levels of the substrates for the bioluminescence reaction (FMNH2 + O-2 and fatty aldehyde --> light). Z-9-Tetradecenal added to yeast (+luxAB) gave a luminescent signal close to that with decanal with the signal remaining strong for >24 h while luminescence of yeast with decanal decayed to less than 0.01% of that with Z-9-tetradecenal after 2min. Moreover, yeast survived in 0.5% (v/v) Z-9-tetradecenal while 0.005% (v/v) decanal was lethal. Luminescence of yeast (+luxAB) was also stimulated 100-fold by transformation with the NADPH-specific FMN reductase (FRP) from Vibrio harveyi. The recognition of the nontoxicity and high luminescence generated by Z-9-tetradecenal and the generation of high levels of FMNH2 in yeast by transformation with a flavin reductase provide evidence for the strong potential use of bacterial luciferase as the light-emitting sensor of choice in eukaryotic organisms. (C) 2003 Elsevier Inc. All rights reserved.