Text: The bioluminescent process of creating light is much more efficient than the sources produced by man. A common household light bulb has an efficiency that is very nearly the opposite of that produced by many animals. The efficiency of a 100-W tungsten light bulb is approximately 10 percent, that is, 10 percent of the electrical energy is converted into useful light. A firefly on the other hand can attain efficiencies of about 88 percent. Bioluminescence has attracted scientists since 1667 when Robert Boyle showed that the light emitted by bacteria and fungus extinquishes when the organisms are deprived of oxygen. It wasn't until about 200 years later that the luminescent process began to be understood. In 1887 Raphael Dubois demonstrated that the bioluminescent process required the existence of a specific compound called luciferin, which interacts with the enzyme luiferase and O2 to produce light. The chemiluminescense process of bioluminescence is a two-step process fueled with luciferin, a Latin word meaning light-bearing. It is combined with an energy-supplying compound ATP (adenosine triphosphate). This compound is found in the cells that are vital for muscle movement in all living creatures, including man. In the process, luciferin oxidizes in reaction to luciferase to produce light. The process is extremely efficient, having been estimated to have a quantum efficiency of 88 percent relative to the consumption of luciferin. The most common bioluminescent colors are white, blue and blue-green, yellow-green (565 nm) green (548 nm) also orange (594 nm) and red. Most fireflies have an emission peak near 562 nm (yellow-green). All emit near this wavelength when the acid-alkaline balance is neutral. The emission peak will shift to longer wavelengths - as long as 614 nm - if the balance is more acidic (i.e., below pH of 7.5), in the presence of denaturants, such as uria, in the presence of heavy metals such as Zn2+, Cd2+ or Hg2+, or if the air temperature is above 20°C.

See Also: LUMINIFEROUS; LIGHT; ETHER; LUMINOSITY; SONOLUMINESCENCE

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