Interesting Facts

The Aequorea victoria jellyfish is part of a unique sect of marine organisms because it is a bioluminescent organism (for another example of a bioluminescent organism click here). The specific reason for the bioluminescence of Aequorea victoria is not fully known, but it only seems to display this trait when disturbed by being touched (Mills, 2008). The first scientist that began to study the bioluminescent properties of Aequorea victoria with the intent of being able to copy and recreate them was Dr. Osamu Shimomura. He began to study the jellyfish at the University of Washington Friday Harbors Laboratory in the summer of 1961. He would extract samples of luminescent liquid called squeezate and analyze its properties (GFP History, 2013). He became the first scientist to discover the components of what is now known as the green fluorescent protein (GFP) and Aequorin (Kendall & Badminton, 1998). Although Dr. Osamu Shimomura helped isolate GFP, thorough research with modern technology has made it possible for us to not only explain in depth how bioluminescence (and even fluorescence) works, but also use it in biomedical processes that range from gene transcription to protein analysis. The discovery of GFP led to Dr. Osamu receiving the Nobel Prize in chemistry in 2008. Bioluminescence is caused by reactions within three major components; a luciferin, luciferase, and molecular oxygen. The luciferase is an enzyme that acts like a catalyst for the oxidation reaction with luciferin, which then produces an unstable electron excited intermediate (Kendall & Badminton, 1998). The intermediate almost immediately loses this excited state and returns to a more stable form by losing the electron known as oxyluciferin (because it has been oxidized). As it loses the electron when it shifts from an unstable to stable state, light is emitted thus producing the bioluminescent effect (Kendall & Badminton, 1998). This reaction only produces light once and is the basic reaction for bioluminescence (Click here for an animated image of the interaction between GFP and Aequorin Green Fluorescent Protein - The GFP Site.mov). The bioluminescence of the Aequorea victoria jellyfish differs though because it uses a photoprotein, which acts much like luciferase but are different in the aspect that photoproteins are already stabilized oxygenated intermediates of the chemicals luciferin and luciferase (Kendall & Badminton, 1998).  This photoprotein is known as aquorin. This chemical contains luciferin with an oxygen attached and when mixed with calcium ions, undergoes an oxidation reaction (Kendall & Badminton, 1998). This reaction produces a blue light and is referred to as the blue fluorescent protein (BFP). BFP is in an excited state and quickly undergoes a radiationless transfer of energy into GFP which then emits a green light as it returns to a stable state. One thing to note is that bioluminescence is not the same as fluorescence. Organisms that use fluorescence receive energy from electromagnetic wavelengths (Kendall & Badminton, 1998). This allows for a short half life followed by decay into a more stable state. Light is emitted during this transition to a more stable state and if energy is continuously provided, it will continue to glow. Other marine species that are capable of producing bioluminescent light use it for a variety of reasons (click here to see other organisms that have the GFP gene). Most marine organisms use bioluminescence as a defense against predators. Jellyfish that float at the surface use it to trick predators that hunt from below into thinking that it is sunlight, since they look for shadows created by creatures (Bioluminescence, 2013). Some species of squid use bioluminescence to confuse predators and prey. There are many uses for bioluminescence that marine organisms use it for and perhaps with more research, scientists can discover what else the Aequorea victoria jellyfish use it for.