The final step of the signaling pathway is acidification of
scintillons due to flux of protons from the vacuole to closely associated
scintillons, vesicles containing the luminescent chemistry, resulting in a flash of light (Fogel and Hastings, 1972; Nawata and Sibaoka, 1979; Johnson et al., 1985; Nicolas et al., 1987).
* Address correspondence to the author at: Department of Photobiology and Bioimaging, The
Scintillon Institute, 6404 Nancy Ridge Dr., San Diego, CA 92121.
In these organisms, light is emitted when the enzyme luciferase oxidizes a substrate, luciferin, contained in small vesicles called
scintillons. Luciferin is normally prevented from reacting by attachment to a luciferin-binding protein; mechanical distortion of the cell plasma membrane generates an electrical action potential that traverses the cell in less than a microsecond (Nicolas et at., 1975), creating an influx of protons that releases luciferin for oxidation.