Bioluminescence is a marine phenomenon present in the world’s deep oceans. This phenomenon is also found on land, as a glowing fungus such Panellus stipticus found on decaying wood. Bioluminescence in this way is called Foxfire or commonly ‘fairy fire’. These beautiful scenes are a result of chemical reaction within organisms. An essential component for bioluminescence to take place are heterocyclic compounds called Luciferins which are substrates that become oxidised in the presence of the enzyme luciferase to produce the inactive oxyluciferin and light energy.
Fluorescence works differently in the way that on an atomic level, a photon with a defined energy excites an electron to a higher energy orbital where it then emits a wavelength of light and returns to a lower energy level where it is more stable.
Bioluminescence is most commonly observed in pelagic species, for example, the cnidarian, Aequorea victoria. This jellyfish is regarded as the “the most influential bioluminescent marine organism”. It is renounced for possessing green fluorescent proteins (GFP) which fluoresce at an emission peak of 509nm (green light).
GFP’s bioluminesce in an enzyme-substrate reaction when a photoprotein (Aequorin) receives positively charged (2+) calcium ions that bind to its active site and cause a chemical response whereby coelenterazine is converted into excited coelenteramide and CO2. Coelenteramide luminesces with a blue light of wavelength 469nm.
GFP’s are currently being studied as an application in early signs of cancer. GFP’s are able to track genes by fluorescent tagging, and have the potential to identify cancerous cells and even metastasis. Osamu Shimomura was awarded the Chemsitry Nobel Prize in 2008 for his discovery of GFP’s.
Written by Aaron Lloyd.