As humans, light and our ability to see is something we take for granted. Vision is arguably the sense we rely on the most. What about nocturnal animals though? Bats of course are masters of echolocation & “see” with sound. What if you need to be seen rather than see?
What is Bioluminescence?
Bioluminescence is light produced by a chemical reaction involving an enzyme, known generically as a luciferase and a compound it reacts with, a luciferin. This mechanism is found in marine organisms, fungi, bacteria and insects.
The Wikipedia article on Bioluminescence is extensive and it lists quite a substantial range of uses by different organisms many of whom evolved this independently. The following paragraph is quoted from the on-line article:
“Defensive functions of startle, counterillumination (camouflage), misdirection (smoke screen), distractive body parts, burglar alarm (making predators into prey), and warnings . Offensive functions to lure, stun, confuse, illuminate prey and mate attraction/recognition.” Some examples are fireflies which use this artificial light to attract mates and angler fish which use lures to attract prey.
What are Some Human Equivalents?
There are of course many equivalents to the above that we humans use. We use timers to turn lights on to make our houses appear occupied to ward off burglars, motion sensors to trigger bright lights and reflective coatings for safety. Fires have been used for centuries to signal to defending armies and lamps for Morse code to avoid radio message interception.
Counterillumination allows animals to match the brightness of their undersides to the light above them as a means of camouflage. Allied aircraft used this technique against German U-Boats in World War II. Bright lights mounted on the front of airplanes would make them nearly invisible against the daytime sky. They could swoop in undetected and bomb the submarines which couldn’t dive fast enough to evade the attacks.
Luciferin is actually a generic term for bioluminescent compounds. It is also used specifically in reference to the firefly version shown below.
Coelenterazine is by far the most common compound used for bioluminescence. Animals as diverse as radiolarians, protozoans, comb jellies, jellyfish, corals, crustaceans, molluscs, arrow worms and some fish use it for one of the purposes listed above.
Bioluminescence in Biotechnology
Bioluminescent compounds have a variety of novel applications. The genes for luciferases can be combined with other genes to act as “reporters” in genome research. These types of genes can also be activated by light to trigger specific chemical reactions and some are being designed into environmentally friendly lighting.
We decided to have a little fun ourselves and substituted our regular clear bonds with our GlowBonds (TM) . The glow in the dark DNA version will be available for sale shortly.
Glow in The Dark Experiment
Not everything that glows in the dark is bioluminescent. Quinine, extracted from the bark of the cinchona tree, has been used to treat malaria for nearly 400 years can. Quinine will fluoresce and glow in the dark when exposed to UV light. Click on the Scientific American Glow in the Dark Experiment to try this at home.
Light-It’s the Speed that Counts
To understand the importance of bioluminescence is to appreciate the nature of light itself. All things considered, its fundamental advantage is its speed of transmission. No other sense allows for as fast a response to need or danger than vision. For this reason alone, many animals have evolved a way to make light where none would normally exist.