* Measured in phosphate-buffered saline, Mujumdar, R. B., Ernst, L. A., Mujumdar, S. R., Lewis, C. J., and Waggoner, A. S. (1993) Bioconjugate Chem. 4, 105-111. Upon attachment to biomolecules (for example oligonucleotides), negligible shifts in excitation and emission wavelength have been observed. In addition no effects on these spectral characteristics have been observed in the presence of 10% DMSO or under a range of pH conditions.