1. Chemistry of Bioluminescence1

2. Outline Introduction Bioluminescence Mechanism
Typical Luciferin Molecules 1

3. Outline
Introduction
Many naturally occurring organisms are bioluminescent, including insects, fungi, bacteria, jellyfish and dinoflagellates.
Bioluminescence has various useful functions:
Finding or attracting prey, example: anglerfish
Defense against predators, example: squid, shrimp
scaleworms and brittlestars.
Communication, example: fireflies.

4. Mechanism
Bioluminescence is light produced by a chemical reaction within an organism.
Two chemicals are required for luminescence
The light-producing compound (luciferin)
The catalyst (luciferase) 1

5. The mechanism of luminescence is regulated by activity of enzymes (luciferases) upon luminescent proteins (luciferins), and requires oxygen.  1

6. Luciferin and dehydroluciferin are exactly alike except for one pair of hydrogen atoms 1

7. The luciferinase attracts an oxygen molecule and gets the oxygen into the best position to attract both hydrogen atoms of the luciferin.
During the departure of the hydrogen atom from the carbon atom next to the nitrogen atom, the second electron of that bond starts to follow the hydrogen atom.
While the shifting of the hydrogen atom is taking place, the point of zero force for the second electron is unusually far from the center of the carbon atom.

8. The two hydrogen atoms move off with the oxygen molecule as hydrogen peroxide
With the hydrogen atoms gone, the point of zero force, which was far from the carbon, returns to a location between the two carbon atoms. This gives the electron a long trip back, driven by potential energy with the distance, and a corresponding store of neg-pos. The electron oscillates with sufficient amplitude to produce a photon with the right resonance frequency. The photon is emitted in the visible range.

9. Typical Luciferin Molecules
Bacterial Luciferin
bacteria, some fish, some squid.
Vargulin
some fish, firefleas.
Dinoflagellate (a structure similar to chlorophyll)
euphausiid shrimp, etc.
Coelenterazine (most common marine luciferins)
squid, shrimp, fish, jellyfish, etc.
Insect
firefly.
Marine Groups with No Known Luminous Members
sponges, heteropods, pteropods, etc. 1

10. bioluminescent bacteria a reduced riboflavin phosphate is oxidized in association with a long-chain aldehyde,oxygen, and a luciferase Vibrio fischeri grown for 24 hours on Photobacterium sea water agar 1

11. Vargulin
There is a clear dietary link, with fish losing their ability toluminescent until they are fed with luciferin-bearing food. 1 1

12. http://www.lifesci.ucsb.edu /~biolum/organism/photo.html
Some lanternfish (myctophids) have very bright light organs near their tail (the white spots above and below the body at the left). These "sternchasers" produce a blinding flash at the instant that the animal darts away, leaving a confused predator in its wake.
/~biolum/organism/photo.html

13. Dinoflagellate luciferin
Is thought to be derived from chlorophyll, and has a very similar structure. 1

14. Euphausia pacifica is a small vertically migrating species of krill
Euphausia pacifica is a small vertically migrating species of krill. It is not clear whether the luminescence, concentrated in photophores along the bottom of the body, is used for counterillumination. (Length approx. 2 cm)

15. Coelenterazine
Coelenterazine is the most "popular" of the marine luciferins, found in a variety of phyla 1

16. This small squid in the genus Abraliopsis has several different types of light organs. In addition to the bean-shaped ones at the tips of two central arms, it has small photophores covering the underside of its body

17. This ctenophore Beroe forskalii illustrates one of the reasons that many transparent organisms have pigmented guts. It has just ingested a lobate ctenophore Leucothea, and if the lights were off, the glow of the luminescing prey would be visible to passing creatures. The Beroe is swimming from right to left in this picture, and its mouth is at the left.

18. Aequorea victoria (jellyfish) is probably the most famous bioluminescent marine organism. Calcium-activated photoprotein and green-fluorescent protein

19. This ctenophore Ocyropsis is heavily parasitized by amphipods, (Length approx. 5 cm)

20. Firefly
the most generally accepted hypothesis is firefly larvae use their luminescence as a warning signal (aposematism) that communicates to potential predators that they taste bad because they have defensive chemicals in their bodies. These larvae also increase both the intensity and frequency of their glow when disturbed

21. Marine Groups with No Known Luminous Members
Heteropods like this Carinaria are some of the very few planktonic organisms which are not bioluminescent. However they still must deal with luminescence.

22. Pteropods, like this Clione, are one of the few kinds of planktonic invertebrates which do not have bioluminescent members.

23. Work sites http://www.lifesci.ucsb.edu/~biolum/