Upper electron-excited states in bioluminescence: experimental indication

The involvement of upper electron-excited states in bacterial bioluminescen ce process was studied with excitation energy-accepting molecules. The fluo rescent aromatic compounds, anthracene and 1.4-bis(5-phenyloxazol-2-yl)benz ene, were chosen. Energies of their lowest excited singlet states are highe r than the energy of the analogous state of the bioluminescence emitter; th eir absorption spectra and bioluminescence do not overlap. Hence, the excit ation of these molecules by singlet-singlet energy transfer or by light abs orption is excluded. Sensitized fluorescence of these compounds in the biol uminescence systems has been recorded, indicating the activity of upper ele ctron-excited states in the bioluminescent process. Copyright (C) 2001 John Wiley & Sons, Ltd.