![Lampyris Noctiluca (firefly) mating](https://upload.wikimedia.org/wikipedia/commons/2/23/Lampyris_Noctiluca_%28firefly%29_mating.gif)
Bioluminescence is the production and emission of
light
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 tera ...
by living
organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and ...
s. It is a form of
chemiluminescence
Chemiluminescence (also chemoluminescence) is the emission of light (luminescence) as the result of a chemical reaction. There may also be limited emission of heat. Given reactants A and B, with an excited intermediate ◊,
: + -> lozenge -> ...
. Bioluminescence occurs widely in marine
vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s and
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s, as well as in some
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
, microorganisms including some
bioluminescent bacteria, and terrestrial arthropods such as
fireflies. In some animals, the light is bacteriogenic, produced by
symbiotic
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
bacteria such as those from the genus ''
Vibrio''; in others, it is autogenic, produced by the animals themselves.
In a general sense, the principal chemical reaction in bioluminescence involves a light-emitting molecule and an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
, generally called
luciferin and
luciferase
Luciferase is a generic term for the class of oxidative enzymes that produce bioluminescence, and is usually distinguished from a photoprotein. The name was first used by Raphaël Dubois who invented the words ''luciferin'' and ''luciferase'', ...
, respectively. Because these are generic names, luciferins and luciferases are often distinguished by the species or group, e.g.
firefly luciferin. In all characterized cases, the enzyme
catalyzes
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
the
oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a d ...
of the luciferin.
In some species, the luciferase requires other
cofactors
Cofactor may also refer to:
* Cofactor (biochemistry), a substance that needs to be present in addition to an enzyme for a certain reaction to be catalysed
* A domain parameter in elliptic curve cryptography, defined as the ratio between the order ...
, such as
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
or
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
ions, and sometimes also the energy-carrying molecule
adenosine triphosphate
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of ...
(ATP). In
evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
, luciferins vary little: one in particular,
coelenterazine, is found in 11 different animal
phyla Phyla, the plural of ''phylum'', may refer to:
* Phylum, a biological taxon between Kingdom and Class
* by analogy, in linguistics, a large division of possibly related languages, or a major language family which is not subordinate to another
Phyl ...
, though in some of these, the animals obtain it through their diet. Conversely, luciferases vary widely between different species, which is evidence that bioluminescence has arisen over 40 times in
evolutionary history.
Both
Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
and
Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic '' ...
mentioned that damp wood sometimes gives off a glow. Many centuries later
Robert Boyle
Robert Boyle (; 25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, alchemist and inventor. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders of ...
showed that oxygen was involved in the process, in both wood and glowworms. It was not until the late nineteenth century that bioluminescence was properly investigated. The phenomenon is widely distributed among animal groups, especially in marine environments. On land it occurs in fungi, bacteria and some groups of
invertebrate
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
s, including
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s.
The uses of bioluminescence by animals include
counterillumination
Counter-illumination is a method of active camouflage seen in marine animals such as firefly squid and midshipman fish, and in military prototypes, producing light to match their backgrounds in both brightness and wavelength.
Marine animals of ...
camouflage,
mimicry
In evolutionary biology, mimicry is an evolved resemblance between an organism and another object, often an organism of another species. Mimicry may evolve between different species, or between individuals of the same species. Often, mimicry f ...
of other animals, for example to lure prey, and
signaling
In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The ''IEEE Transactions on Signal Processing'' ...
to other individuals of the same species, such as to attract mates. In the laboratory, luciferase-based systems are used in genetic engineering and biomedical research. Researchers are also investigating the possibility of using bioluminescent systems for street and decorative lighting, and a bioluminescent plant has been created.
History
Before the development of the
safety lamp for use in coal mines, dried fish skins were used in Britain and Europe as a weak source of light. This experimental form of illumination avoided the necessity of using candles which risked sparking explosions of
firedamp
Firedamp is any flammable gas found in coal mines, typically coalbed methane. It is particularly found in areas where the coal is bituminous. The gas accumulates in pockets in the coal and adjacent strata and when they are penetrated the releas ...
.
Another safe source of illumination in mines was bottles containing fireflies.
In 1920, the American zoologist
E. Newton Harvey
Edmund Newton Harvey (November 25, 1887 – July 21, 1959) was an American zoologist. He was acknowledged as one of the leading authorities on bioluminescence. He won the Rumford Prize in 1947 and was a member of the National Academy of Science ...
published a monograph, ''The Nature of Animal Light'', summarizing early work on bioluminescence. Harvey notes that
Aristotle
Aristotle (; grc-gre, Ἀριστοτέλης ''Aristotélēs'', ; 384–322 BC) was a Greek philosopher and polymath during the Classical period in Ancient Greece. Taught by Plato, he was the founder of the Peripatetic school of phil ...
mentions light produced by dead fish and flesh, and that both Aristotle and
Pliny the Elder
Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic '' ...
(in his ''
Natural History'') mention light from damp wood. He also records that
Robert Boyle
Robert Boyle (; 25 January 1627 – 31 December 1691) was an Anglo-Irish natural philosopher, chemist, physicist, alchemist and inventor. Boyle is largely regarded today as the first modern chemist, and therefore one of the founders of ...
experimented on these light sources, and showed that both they and the glowworm require air for light to be produced. Harvey notes that in 1753, J. Baker identified the flagellate ''
Noctiluca'' "as a luminous animal" "just visible to the naked eye", and in 1854
Johann Florian Heller
Johann Florian Heller (4 May 1813 – 21 November 1871) was an Austrian chemist who was one of the founders of clinical chemistry.
Heller was born in Vienna, Austria. He studied chemistry in Prague and later with Liebig and Wöhler at Giessen.
...
(1813–1871) identified strands (
hypha
A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium.
Structure
A hypha consists of one or ...
e) of fungi as the source of light in dead wood.
Tuckey, in his posthumous 1818 ''Narrative of the Expedition to the Zaire'', described catching the animals responsible for luminescence. He mentions pellucids, crustaceans (to which he ascribes the milky whiteness of the water), and cancers (shrimps and crabs). Under the microscope he described the "luminous property" to be in the brain, resembling "a most brilliant amethyst about the size of a large pin's head".
Charles Darwin
Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...
noticed bioluminescence in the sea, describing it in his ''Journal'':
While sailing in these latitudes on one very dark night, the sea presented a wonderful and most beautiful spectacle. There was a fresh breeze, and every part of the surface, which during the day is seen as foam, now glowed with a pale light. The vessel drove before her bows two billows of liquid phosphorus, and in her wake she was followed by a milky train. As far as the eye reached, the crest of every wave was bright, and the sky above the horizon, from the reflected glare of these livid flames, was not so utterly obscure, as over the rest of the heavens.
Darwin also observed a luminous "jelly-fish of the genus Dianaea",
[ noting that: "When the waves scintillate with bright green sparks, I believe it is generally owing to minute crustacea. But there can be no doubt that very many other pelagic animals, when alive, are phosphorescent."][ He guessed that "a disturbed electrical condition of the atmosphere"][ was probably responsible. Daniel Pauly comments that Darwin "was lucky with most of his guesses, but not here",] noting that biochemistry was too little known, and that the complex evolution of the marine animals involved "would have been too much for comfort".[
]
Bioluminescence attracted the attention of the United States Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
in the Cold War
The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because the ...
, since submarines in some waters can create a bright enough wake to be detected; a German submarine was sunk in the First World War
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...
, having been detected in this way. The navy was interested in predicting when such detection would be possible, and hence guiding their own submarines to avoid detection.[
Among the anecdotes of navigation by bioluminescence is one recounted by the ]Apollo 13
Apollo 13 (April 1117, 1970) was the seventh crewed mission in the Apollo space program and the third meant to land on the Moon. The craft was launched from Kennedy Space Center on April 11, 1970, but the lunar landing was aborted aft ...
astronaut Jim Lovell, who as a navy pilot had found his way back to his aircraft carrier USS ''Shangri-La'' when his navigation systems failed. Turning off his cabin lights, he saw the glowing wake of the ship, and was able to fly to it and land safely.
The French
French (french: français(e), link=no) may refer to:
* Something of, from, or related to France
** French language, which originated in France, and its various dialects and accents
** French people, a nation and ethnic group identified with Franc ...
pharmacologist Raphaël Dubois
Raphaël Horace Dubois (20 June 1849, Le Mans – 21 January 1929) was a French pharmacologist known for his work on bioluminescence and anesthesia. He coined the terms ''proteon'' and ''bioproteon,'' from the Greek "proteon" for matter and "bios ...
carried out work on bioluminescence in the late nineteenth century. He studied click beetles
Elateridae or click beetles (or "typical click beetles" to distinguish them from the related families Cerophytidae and Eucnemidae, which are also capable of clicking) are a family of beetles. Other names include elaters, snapping beetles, s ...
(''Pyrophorus'') and the marine bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...
mollusc ''Pholas dactylus
''Pholas dactylus'', or common piddock, is a bioluminescent clam-like species of marine mollusc found on the coasts of the North Atlantic and the Mediterranean Sea. It bores into gneiss. It was once a highly esteemed food in Europe.Gofas, S. (20 ...
''. He refuted the old idea that bioluminescence came from phosphorus, and demonstrated that the process was related to the oxidation of a specific compound, which he named luciferin, by an enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
. He sent Harvey siphons
A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in a ...
from the mollusc preserved in sugar. Harvey had become interested in bioluminescence as a result of visiting the South Pacific and Japan and observing phosphorescent organisms there. He studied the phenomenon for many years. His research aimed to demonstrate that luciferin, and the enzymes that act on it to produce light, were interchangeable between species, showing that all bioluminescent organisms had a common ancestor. However, he found this hypothesis to be false, with different organisms having major differences in the composition of their light-producing proteins. He spent the next 30 years purifying and studying the components, but it fell to the young Japanese chemist Osamu Shimomura to be the first to obtain crystalline luciferin. He used the sea firefly ''Vargula hilgendorfii'', but it was another ten years before he discovered the chemical's structure and published his 1957 paper ''Crystalline Cypridina Luciferin''.[ Shimomura, Martin Chalfie, and ]Roger Y. Tsien
Roger Yonchien Tsien (pronounced , "'' CHEN''"'';'' February 1, 1952 – August 24, 2016) was an American biochemist. He was a professor of chemistry and biochemistry at the University of California, San Diego and was awarded the Nobel Prize in ...
won the 2008 Nobel Prize in Chemistry
)
, image = Nobel Prize.png
, alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...
for their 1961 discovery and development of green fluorescent protein
The green fluorescent protein (GFP) is a protein that exhibits bright green fluorescence when exposed to light in the blue to ultraviolet range. The label ''GFP'' traditionally refers to the protein first isolated from the jellyfish ''Aequorea ...
as a tool for biological research.
Harvey wrote a detailed historical account on all forms of luminescence in 1957. An updated book on bioluminescence covering also the twentieth and early twenty-first century was published recently.
Evolution
In 1932 E. N. Harvey was among the first to propose how bioluminescence could have evolved. In this early paper, he suggested that proto-bioluminescence could have arisen from respiratory chain proteins that hold fluorescent groups. This hypothesis has since been disproven, but it did lead to considerable interest in the origins of the phenomenon. Today, the two prevailing hypotheses (both concerning marine bioluminescence) are those put forth by Howard Seliger in 1993 and Rees et al. in 1998.
Seliger's theory identifies luciferase enzymes as the catalyst for the evolution of bioluminescent systems. It suggests that the original purpose of luciferases was as mixed-function oxygenases. As the early ancestors of many species moved into deeper and darker waters natural selection favored the development of increased eye sensitivity and enhanced visual signals. If selection were to favor a mutation in the oxygenase enzyme required for the breakdown of pigment molecules (molecules often associated with spots used to attract a mate or distract a predator) it could have eventually resulted in external luminescence in tissues.[
Rees et al. use evidence gathered from the marine luciferin coelenterazine to suggest that selection acting on luciferins may have arisen from pressures to protect oceanic organisms from potentially deleterious reactive oxygen species (e.g. H2O2 and O2− ). The functional shift from antioxidation to bioluminescence probably occurred when the strength of selection for antioxidation defense decreased as early species moved further down the water column. At greater depths exposure to ROS is significantly lower, as is the endogenous production of ROS through metabolism.][
While popular at first, Seliger's theory has been challenged, particularly on the biochemical and genetic evidence that Rees examines. What remains clear, however, is that bioluminescence has evolved independently at least 40 times. Bioluminescence in fish began at least by the ]Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
period. About 1,500 fish species are known to be bioluminescent; the capability evolved independently at least 27 times. Of these, 17 involved the taking up of bioluminous bacteria from the surrounding water while in the others, the intrinsic light evolved through chemical synthesis. These fish have become surprisingly diverse in the deep ocean and control their light with the help of their nervous system, using it not just to lure prey or hide from predators, but also for communication.
All bioluminescent organisms have in common that the reaction of a "luciferin" and oxygen is catalyzed by a luciferase to produce light. McElroy and Seliger proposed in 1962 that the bioluminescent reaction evolved to detoxify oxygen, in parallel with photosynthesis.
Thuesen, Davis et al. showed in 2016 that bioluminescence has evolved independently 27 times within 14 fish clades across ray-finned fishes.
Chemical mechanism
Bioluminescence is a form of chemiluminescence
Chemiluminescence (also chemoluminescence) is the emission of light (luminescence) as the result of a chemical reaction. There may also be limited emission of heat. Given reactants A and B, with an excited intermediate ◊,
: + -> lozenge -> ...
where light energy is released by a chemical reaction. This reaction involves a light-emitting pigment, the luciferin, and a luciferase
Luciferase is a generic term for the class of oxidative enzymes that produce bioluminescence, and is usually distinguished from a photoprotein. The name was first used by Raphaël Dubois who invented the words ''luciferin'' and ''luciferase'', ...
, the enzyme component.[ Because of the diversity of luciferin/luciferase combinations, there are very few commonalities in the chemical mechanism. From currently studied systems, the only unifying mechanism is the role of molecular ]oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
; often there is a concurrent release of carbon dioxide
Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...
(CO2). For example, the firefly luciferin/luciferase reaction requires magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
and ATP
ATP may refer to:
Companies and organizations
* Association of Tennis Professionals, men's professional tennis governing body
* American Technical Publishers, employee-owned publishing company
* ', a Danish pension
* Armenia Tree Project, non ...
and produces CO2, adenosine monophosphate (AMP) and pyrophosphate (PP) as waste products. Other cofactors may be required, such as calcium (Ca2+) for the photoprotein aequorin
Aequorin is a calcium-activated photoprotein isolated from the hydrozoan ''Aequorea victoria''. Its bioluminescence was studied decades before the protein was isolated from the animal by Osamu Shimomura in 1962. In the animal, the protein occurs ...
, or magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...
(Mg2+) ions and ATP for the firefly luciferase. Generically, this reaction can be described as:
:Luciferin + O2-> text\text]Oxyluciferin + light energy
Instead of a luciferase, the jellyfish '' Aequorea victoria'' makes use of another type of protein called a photoprotein, in this case specifically aequorin
Aequorin is a calcium-activated photoprotein isolated from the hydrozoan ''Aequorea victoria''. Its bioluminescence was studied decades before the protein was isolated from the animal by Osamu Shimomura in 1962. In the animal, the protein occurs ...
. When calcium ions are added, rapid catalysis
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
creates a brief flash quite unlike the prolonged glow produced by luciferase. In a second, much slower step, luciferin is regenerated from the oxidized (oxyluciferin) form, allowing it to recombine with aequorin, in preparation for a subsequent flash. Photoproteins are thus enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
s, but with unusual reaction kinetics. Furthermore, some of the blue light released by aequorin in contact with calcium ions is absorbed by a green fluorescent protein
The green fluorescent protein (GFP) is a protein that exhibits bright green fluorescence when exposed to light in the blue to ultraviolet range. The label ''GFP'' traditionally refers to the protein first isolated from the jellyfish ''Aequorea ...
, which in turn releases green light in a process called resonant energy transfer.
Overall, bioluminescence has arisen over 40 times in evolutionary history.[ In ]evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
, luciferins tend to vary little: one in particular, coelenterazine, is the light emitting pigment for nine phyla Phyla, the plural of ''phylum'', may refer to:
* Phylum, a biological taxon between Kingdom and Class
* by analogy, in linguistics, a large division of possibly related languages, or a major language family which is not subordinate to another
Phyl ...
(groups of very different organisms), including polycystine radiolaria, Cercozoa
Cercozoa is a phylum of diverse single-celled eukaryotes. They lack shared morphological characteristics at the microscopic level, and are instead defined by molecular phylogenies of rRNA and actin or polyubiquitin. They were the first major eu ...
(Phaeodaria
Phaeodarea, or Phaeodaria, is a group of amoeboid cercozoan organisms. They are traditionally considered radiolarians, but in molecular trees do not appear to be close relatives of the other groups, and are instead placed among the Cercozoa. They ...
), protozoa
Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...
, comb jellies, cnidaria
Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter.
Their distinguishing feature is cnidocytes, specialized cells that th ...
including jellyfish
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...
and coral
Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...
s, crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, molluscs, arrow worms
The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can ...
and vertebrate
Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
s (ray-finned fish
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species.
The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...
). Not all these organisms synthesise coelenterazine: some of them obtain it through their diet.[ Conversely, luciferase enzymes vary widely and tend to be different in each species.][
]
Distribution
Bioluminescence occurs widely among animals, especially in the open sea, including fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
, jellyfish
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...
, comb jellies, crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, and cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
molluscs; in some fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
and bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
; and in various terrestrial invertebrates including insects. In marine coastal habitats, about 2.5% of organisms are estimated to be bioluminescent, whereas in pelagic habitats in the eastern Pacific, about 76% of the main taxa of deep-sea animals have been found to be capable of producing light. Most marine light-emission is in the blue and green light spectrum
The electromagnetic spectrum is the range of frequency, frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energy, photon energies.
The electromagnetic spectrum covers electromagnetic waves with f ...
. However, some loose-jawed fish emit red and infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
light, and the genus ''Tomopteris
The gossamer worm (''Tomopteris'', Neo-Latin from Greek meaning "a cut" + "wing" but taken to mean "fin") is a genus of marine planktonic polychaetes.
All described species are known to be holoplanktic, meaning that they spend their entire lif ...
'' emits yellow light.[
The most frequently encountered bioluminescent organisms may be the ]dinoflagellate
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...
s in the surface layers of the sea, which are responsible for the sparkling phosphorescence sometimes seen at night in disturbed water. At least 18 genera exhibit luminosity.[ A different effect is the thousands of square miles of the ocean which shine with the light produced by bioluminescent bacteria, known as mareel or the milky seas effect.
]
Pelagic zone
Bioluminescence is abundant in the pelagic zone, with the most concentration at depths devoid of light and surface waters at night. These organisms participate in diurnal vertical migration from the dark depths to the surface at night, dispersing the population of bioluminescent organisms across the pelagic water column. The dispersal of bioluminescence across different depths in the pelagic zone has been attributed to the selection pressures imposed by predation and the lack of places to hide in the open sea. In depths where sunlight never penetrates, often below 200m, the significance of bioluminescent is evident in the retainment of functional eyes for organisms to detect bioluminescence.
Bacterial symbioses
Organisms often produce bioluminescence themselves, rarely do they generate it from outside phenomena. However, there are occasions where bioluminescence is produced by bacterial symbionts that have a symbiotic relationship with the host organism. Although many luminous bacteria in the marine environment are free-living, a majority are found in symbiotic relationships that involve fish, squids, crustaceans etc. as hosts. Most luminous bacterial inhabit the marine sea, with ''Photobacterium
''Photobacterium'' is a genus of gram-negative, oxidase positive and catalase positive bacteria in the family ''Vibrionaceae''. Members of the genus are bioluminescent, that is they have the ability to emit light.
Many species, including '' Pho ...
'' and '' Vibrio'' genera dominating the marine environment.
In the symbiotic relationship, bacterium benefit from having a source of nourishment and a refuge to grow. Hosts obtain these bacterial symbionts either from the environment, spawning, or the luminous bacterium is evolving with their host. Coevolutionary interactions are suggested as host organisms’ anatomical adaptations have become specific to only certain luminous bacteria, to suffice ecological dependence of bioluminescence.
Benthic zone
Bioluminescence is widely studied amongst species located in the mesopelagic zone, but the benthic zone
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning " ...
at mesopelagic depths has remained widely unknown. Benthic habitats at depths beyond the mesopelagic are also poorly understood due to the same constraints. Unlike the pelagic zone where the emission of light is undisturbed in the open sea, the occurrence of bioluminescence in the benthic zone is less common. It has been attributed to the blockage of emitted light by a number of sources such as the sea floor, and inorganic and organic structures. Visual signals and communication that is prevalent in the pelagic zone such as counterillumination may not be functional or relevant in the benthic realm. Bioluminescence in bathyal benthic species still remains poorly studied due to difficulties of the collection of species at these depths.
Uses in nature
Bioluminescence has several functions in different taxa. Steven Haddock Steven H. D. Haddock is a marine biologist known for his work on bioluminescence of the jellylike animals of the open ocean and the deep sea, and the photoproteins and fluorescent proteins of these animals.
Life
Haddock was educated at Harvey Mudd ...
et al. (2010) list as more or less definite functions in marine organisms the following: defensive functions of startle, counterillumination (camouflage), misdirection (smoke screen), distractive body parts, burglar alarm (making predators easier for higher predators to see), and warning to deter settlers; offensive functions of lure, stun or confuse prey, illuminate prey, and mate attraction/recognition. It is much easier for researchers to detect that a species is able to produce light than to analyze the chemical mechanisms or to prove what function the light serves.[ In some cases the function is unknown, as with species in three families of earthworm ( Oligochaeta), such as '']Diplocardia longa
''Diplocardia longa'' is a species of earthworm native to North America. It was first described by the American zoologist John Percy Moore in 1904. The type locality is Hawkinsville, Georgia. This worm has bioluminescent properties; its body ...
'' where the coelomic fluid produces light when the animal moves.[ The following functions are reasonably well established in the named organisms.
]
Counterillumination camouflage
In many animals of the deep sea, including several squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
species, bacterial bioluminescence is used for camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
by counterillumination
Counter-illumination is a method of active camouflage seen in marine animals such as firefly squid and midshipman fish, and in military prototypes, producing light to match their backgrounds in both brightness and wavelength.
Marine animals of ...
, in which the animal matches the overhead environmental light as seen from below. In these animals, photoreceptors control the illumination to match the brightness of the background. These light organs are usually separate from the tissue containing the bioluminescent bacteria. However, in one species, ''Euprymna scolopes
__NOTOC__
''Euprymna scolopes'', also known as the Hawaiian bobtail squid, is a species of bobtail squid in the family Sepiolidae native to the central Pacific Ocean, where it occurs in shallow coastal waters off the Hawaiian Islands and Midway ...
'', the bacteria are an integral component of the animal's light organ.
Attraction
Bioluminescence is used in a variety of ways and for different purposes. The cirrate octopod ''Stauroteuthis syrtensis'' uses emits bioluminescence from its sucker like structures. These structures are believed to have evolved from what are more commonly known as octopus suckers. They do not have the same function as the normal suckers because they no longer have any handling or grappling ability due its evolution of photophores. The placement of the photophores are within the animals oral reach, which leads researchers to suggest that it uses it bioluminescence to capture and lure prey.
Fireflies use light to attract mates. Two systems are involved according to species; in one, females emit light from their abdomens to attract males; in the other, flying males emit signals to which the sometimes sedentary females respond.[ Click beetles emit an orange light from the abdomen when flying and a green light from the thorax when they are disturbed or moving about on the ground. The former is probably a sexual attractant but the latter may be defensive.][ Larvae of the click beetle '']Pyrophorus nyctophanus
''Pyrophorus nyctophanus'' (=''fire-bearing night-shiner''), aka headlight beetle or carbunco, is a species of click beetle that occurs on the cerrado of Brazil. Its luminescent larvae are either soil-dwelling or found in tunnels in the outer la ...
'' live in the surface layers of termite mounds in Brazil. They light up the mounds by emitting a bright greenish glow which attracts the flying insects on which they feed.[
In the marine environment, use of luminescence for mate attraction is chiefly known among ]ostracod
Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...
s, small shrimplike crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s, especially in the family Cyprididae
Cyprididae is "the most diverse group of freshwater ostracods". It contains over 1000 species, which represents 50% of the known species of fresh water, freshwater ostracods (other speciose families include Candonidae, with 25%, and Limnocytheri ...
. Pheromones may be used for long-distance communication, with bioluminescence used at close range to enable mates to "home in".[ A polychaete worm, the Bermuda fireworm creates a brief display, a few nights after the full moon, when the female lights up to attract males.
]
Defense
The defense mechanisms for bioluminescent organisms can come in multiple forms; startling prey, counterillumination, smoke screen or misdirection, distractive body parts, burglar alarm, sacrificial tag or warning coloration. The shrimp family Oplophoridae Dana use their bioluminescence as a way of startling the predator that is after them. ''Acanthephyra purpurea'', within the Oplophoridae family, uses its photophores to emit light, and can secrete a bioluminescent substance when in the presence of a predator. This secretory mechanism is common among prey fish.
Many cephalopod
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head ...
s, including at least 70 genera
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
of squid
True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...
, are bioluminescent.[ Some squid and small ]crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
s use bioluminescent chemical mixtures or bacterial slurries in the same way as many squid use ink
Ink is a gel, sol, or solution that contains at least one colorant, such as a dye or pigment, and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, reed pen, or quill. Thi ...
. A cloud of luminescent material is expelled, distracting or repelling a potential predator, while the animal escapes to safety. The deep sea squid ''Octopoteuthis deletron
''Octopoteuthis deletron'' is a species of squid in the genus '' Octopoteuthis'' of the family Octopoteuthidae. They belong to the pelagic squids of order Oegopsida. Found at depths of in the Pacific Ocean, they have been known to grow to .
'' ...
'' may autotomise portions of its arms which are luminous and continue to twitch and flash, thus distracting a predator while the animal flees.[
]Dinoflagellate
The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...
s may use bioluminescence for defense against predator
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...
s. They shine when they detect a predator, possibly making the predator itself more vulnerable by attracting the attention of predators from higher trophic levels.[ Grazing copepods release any phytoplankton cells that flash, unharmed; if they were eaten they would make the copepods glow, attracting predators, so the phytoplankton's bioluminescence is defensive. The problem of shining stomach contents is solved (and the explanation corroborated) in predatory deep-sea fishes: their stomachs have a black lining able to keep the light from any bioluminescent fish prey which they have swallowed from attracting larger predators.][
The sea-firefly is a small crustacean living in sediment. At rest it emits a dull glow but when disturbed it darts away leaving a cloud of shimmering blue light to confuse the predator. During World War II it was gathered and dried for use by the Japanese army as a source of light during clandestine operations.]
The larvae of railroad worms (''Phrixothrix'') have paired photic organs on each body segment, able to glow with green light; these are thought to have a defensive purpose. They also have organs on the head which produce red light; they are the only terrestrial organisms to emit light of this color.
Warning
Aposematism
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...
is a widely used function of bioluminescence, providing a warning that the creature concerned is unpalatable. It is suggested that many firefly larvae glow to repel predators; some millipedes glow for the same purpose. Some marine organisms are believed to emit light for a similar reason. These include scale worms, jellyfish
Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria. Jellyfish are mainly free-swimming marine animals with umbrella- ...
and brittle stars but further research is needed to fully establish the function of the luminescence. Such a mechanism would be of particular advantage to soft-bodied cnidaria
Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter.
Their distinguishing feature is cnidocytes, specialized cells that th ...
ns if they were able to deter predation in this way.[ The ]limpet
Limpets are a group of aquatic snails that exhibit a conical shell shape (patelliform) and a strong, muscular foot. Limpets are members of the class Gastropoda, but are polyphyletic, meaning the various groups called "limpets" descended indep ...
''Latia neritoides
''Latia neritoides'' is a species of small freshwater snail or limpet, an Aquatic animal, aquatic gastropod mollusc in the family (biology), family Latiidae.
The type specimen is in the British Museum.
The specific epithet "neritoides" means "l ...
'' is the only known freshwater gastropod
The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda ().
This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...
that emits light. It produces greenish luminescent mucus
Mucus ( ) is a slippery aqueous secretion produced by, and covering, mucous membranes. It is typically produced from cells found in mucous glands, although it may also originate from mixed glands, which contain both serous and mucous cells. It is ...
which may have an anti-predator function. The marine snail ''Hinea brasiliana
''Hinea brasiliana'', common name the yellow-coated clusterwink, is a species of small sea snail, a gastropod mollusc in the family Planaxidae. It is native to New Zealand and southeastern Australia where it is found in the littoral zone of rock ...
'' uses flashes of light, probably to deter predators. The blue-green light is emitted through the translucent shell, which functions as an efficient diffuser of light.
Communication
Communication in the form of quorum sensing plays a role in the regulation of luminescence in many species of bacteria. Small extracellularly secreted molecules stimulate the bacteria to turn on genes for light production when cell density, measured by concentration of the secreted molecules, is high.[
Pyrosomes are colonial tunicates and each ]zooid
A zooid or zoöid is a single animal that is part of a colonial animal. This lifestyle has been adopted by animals from separate unrelated taxa. Zooids are multicellular; their structure is similar to that of other solitary animals. The zooi ...
has a pair of luminescent organs on either side of the inlet siphon. When stimulated by light, these turn on and off, causing rhythmic flashing. No neural pathway runs between the zooids, but each responds to the light produced by other individuals, and even to light from other nearby colonies. Communication by light emission between the zooids enables coordination of colony effort, for example in swimming where each zooid provides part of the propulsive force.
Some bioluminous bacteria infect nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhab ...
s that parasitize Lepidoptera
Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...
larvae. When these caterpillar
Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths).
As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Sym ...
s die, their luminosity may attract predators to the dead insect thus assisting in the dispersal of both bacteria and nematodes. A similar reason may account for the many species of fungi that emit light. Species in the genera '' Armillaria'', ''Mycena
''Mycena'' is a large genus of small saprotrophic mushrooms that are rarely more than a few centimeters in width. They are characterized by a white spore print, a small conical or bell-shaped cap, and a thin fragile stem. Most are gray or bro ...
'', '' Omphalotus'', ''Panellus
''Panellus'' is a genus of more than 50 mushroom species of fungi in the family Mycenaceae as defined molecularly. Prior to molecular analyses the generic name had been used for any white-spored '' pleurotoid'' with amyloid spores. Unrelated but ...
'', ''Pleurotus
''Pleurotus'' is a genus of gilled mushrooms which includes one of the most widely eaten mushrooms, '' P. ostreatus''. Species of ''Pleurotus'' may be called oyster, abalone, or tree mushrooms, and are some of the most commonly cultivated edib ...
'' and others do this, emitting usually greenish light from the mycelium
Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrate (biology), substrates. A typical single ...
, cap and gills. This may attract night-flying insects and aid in spore dispersal, but other functions may also be involved.[
'']Quantula striata
''Quantula striata'', also known as ''Dyakia striata'', is a species of medium-sized, air-breathing, tropical land snail. It is a terrestrial, pulmonate, gastropod mollusk in the family Dyakiidae. This species appears to be unique among terrestri ...
'' is the only known bioluminescent terrestrial mollusc. Pulses of light are emitted from a gland near the front of the foot and may have a communicative function, although the adaptive significance is not fully understood.
Mimicry
Bioluminescence is used by a variety of animals to mimic
MIMIC, known in capitalized form only, is a former simulation computer language developed 1964 by H. E. Petersen, F. J. Sansom and L. M. Warshawsky of Systems Engineering Group within the Air Force Materiel Command at the Wright-Patterson AFB in ...
other species. Many species of deep sea fish
Deep-sea fish are fish that live in the darkness below the sunlit surface waters, that is below the epipelagic or photic zone of the sea. The lanternfish is, by far, the most common deep-sea fish. Other deep sea fishes include the flashlight ...
such as the anglerfish
The anglerfish are fish of the teleost order Lophiiformes (). They are bony fish named for their characteristic mode of predation, in which a modified luminescent fin ray (the esca or illicium) acts as a lure for other fish. The luminescence ...
and dragonfish make use of aggressive mimicry to attract prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
. They have an appendage
An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body.
In arthropods, an appendage refers to any of the homologous body parts that may extend from a body segment, including anten ...
on their heads called an esca
The anglerfish are fish of the teleost order Lophiiformes (). They are bony fish named for their characteristic mode of predation, in which a modified luminescent fin ray (the esca or illicium) acts as a lure for other fish. The luminescence co ...
that contains bioluminescent bacteria able to produce a long-lasting glow which the fish can control. The glowing esca is dangled or waved about to lure small animals to within striking distance of the fish.[
The cookiecutter shark uses bioluminescence to camouflage its underside by counterillumination, but a small patch near its pectoral fins remains dark, appearing as a small fish to large predatory fish like ]tuna
A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...
and mackerel
Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment.
...
swimming beneath it. When such fish approach the lure, they are bitten by the shark.
Female ''Photuris
''Photuris'' is a genus of fireflies (beetles of the family Lampyridae). These are the ''femme fatale'' lightning bugs of North America. This common name refers to a behavior of the adult females of these predatory beetles; they engage in aggr ...
'' fireflies sometimes mimic the light pattern of another firefly, ''Photinus'', to attract its males as prey. In this way they obtain both food and the defensive chemicals named lucibufagin
A lucibufagin is a defensive steroid produced by several species of firefly to make them unpalatable to predators such as spiders and bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by ...
s, which ''Photuris'' cannot synthesize.
South American giant cockroaches of the genus '' Lucihormetica'' were believed to be the first known example of defensive mimicry, emitting light in imitation of bioluminescent, poisonous click beetles. However, doubt has been cast on this assertion, and there is no conclusive evidence that the cockroaches are bioluminescent.
Illumination
While most marine bioluminescence is green to blue, some deep sea barbeled dragonfishes in the genera ''Aristostomias
''Aristostomias'' is a genus of barbeled dragonfishes native to the ocean depths in the Pacific, Atlantic and Indian oceans.
Red Light Bioluminescence
Production of red light bioluminescence
Similar to other deep-sea organisms that are capa ...
'', ''Pachystomias
''Pachystomias microdon'', the smalltooth dragonfish, is a species of barbeled dragonfish found in the oceans at depths of from . This species grows to a length of SL. This species is the only known species in its genus.
Red Light Biolumine ...
'' and ''Malacosteus'' emit a red glow. This adaptation allows the fish to see red-pigmented prey, which are normally invisible to other organisms in the deep ocean environment where red light has been filtered out by the water column. The fish is able to utilize the longer wavelength to act as a spotlight for its prey that only it is able to see. In addition to the utilization of the light for predation, it has been hypothesized that the fish use this to communicate with each other to find potential mates. The ability of the fish to see this light is explained by the presence of specialized rhodopsin pigment. The angler siphonophore (Erenna), also utilizes red bioluminescence in appendages to lure fish.
The mechanism of light creation is through a suborbital photophore that utilizes gland cells which produce exergonic chemical reactions that produce light with a longer, red wavelength. The dragonfish species which produce the red light also produce blue light in photophore on the dorsal area. The main function of this is to alert the fish to the presence of its prey. The additional pigment is thought to be assimilated from chlorophyll derivatives found in the copepods which form part of its diet.
Biotechnology
Biology and medicine
Bioluminescent organisms are a target for many areas of research. Luciferase systems are widely used in genetic engineering as reporter genes, each producing a different color by fluorescence, and for biomedical research using bioluminescence imaging. For example, the firefly luciferase gene was used as early as 1986 for research using transgenic tobacco plants. ''Vibrio'' bacteria symbiose with marine invertebrates such as the Euprymna scolopes, Hawaiian bobtail squid (''Euprymna scolopes''), are key model organism, experimental models for bioluminescence. Bioluminescent activated destruction is an experimental cancer treatment.
''In Vivo'' luminescence cell and animal imaging uses dyes and fluorescent proteins as chromophores. The characteristics of each chromophore determine which cell area(s) will be targeted and illuminated.
Light production
The structures of photophores, the light producing organs in bioluminescent organisms, are being investigated by industrial designers. Engineered bioluminescence could perhaps one day be used to reduce the need for street lighting, or for decorative purposes if it becomes possible to produce light that is both bright enough and can be sustained for long periods at a workable price.[Bioluminescence Questions and Answers]
Siobiolum.ucsd.edu. Retrieved on 20 October 2011. The gene that makes the tails of fireflies glow has been added to mustard plants. The plants glow faintly for an hour when touched, but a sensitive camera is needed to see the glow. University of Wisconsin–Madison is researching the use of genetically engineered bioluminescent Escherichia coli, E. coli bacteria, for use as bioluminescent bacteria in a light bulb.
In 2011, Philips launched a microbial system for ambience lighting in the home.
An International Genetically Engineered Machine, iGEM team from Cambridge (England) has started to address the problem that luciferin is consumed in the light-producing reaction by developing a genetic biotechnology part that codes for a luciferin regenerating enzyme from the North American firefly.
In 2016, Glowee, a French company started selling bioluminescent lights for shop fronts and street signs, for use between 1 and 7 in the morning when the law forbids use of electricity for this purpose. They used the bioluminescent bacterium ''Aliivibrio fischeri'', but the maximum lifetime of their product was three days.
In April 2020, plants were genetically engineered to glow more brightly using genes from the bioluminescent mushroom ''Neonothopanus nambi'' to convert caffeic acid into luciferin.
ATP bioluminescence
ATP bioluminescence is the process in which ATP is used to generate luminescence in an organism. It proves to be a very good biosensor to test cell viability. Optical biosensors include process of measurement of ''luminescence, fluorescence absorbance or emission''. Through these measurements, quantitative measurement of ATP bioluminescence is applied to detect existence of living microbes only. Since the method is quick and convenient, it results in real-time data. It is faster, economical and easier to work with. Optical biosensors sense the observed optical signal based on measuring the photons involved in the phenomenon (''spiking'') It depends on the interaction of microbes with analytes. Thus, it is correlated with the concentration of the microbial population which is determined through this method.
Differentiation between living and non living cells
In ATP bioluminescence, it is assumed that all living cells in the same have the same amount of ATP over time during the chemical reaction between luciferin, luciferase to produce ATP, This is done in order to measure the viability of the cell and allows the researcher to measure the amount of living and dead cells in the sample on basis of presence or absence of ATP. Living cells that contain ATP produce a bioluminescent flash due to the ''luciferin-luciferase reaction'' in presence of ATP. Dead cells do not produce any bioluminescence due to absence of ATP The amount of the intensity of the signal is constant for each living cell in a healthy sample. In this way, the overall number of living cells within a sample is determined.
= Process of measurement of microbial population
=
ATP, which is a fundamental compound in the luciferase reaction, is utilized and in the second step, oxyluciferin is produced. The oxyluciferin is produced in an excited state, which produces light when it goes back to ground state. The light emitted is detected by a luminometer. Concentration of the ATP is directly proportional to the expressed light measured as Relative Light Units (RLU). A receiver operating characteristic (ROC) is used to calculate the sensitivity and specificity of the measurements. There is direct correlation between luminescence intensity and concentration of standard ATP. There is a direct correlation between bioluminescence and colony forming unit (CFU). Thus, concentration of standard ATP and CFU gives a standard correlation. In this way, ATP is measured and microbial population is determined through bioluminescence.
However, it is important to keep in mind that different types of microbial populations are determined through different sets of ATP assays using other substrates and reagents. ''Renilla'' and ''Gaussia'' based cell viability assays use the substrate coelenterazine.
See also
*Animal coloration
*Biophoton
*''Life That Glows'', 2016 full-length documentary
Notes
References
Further reading
* Victor Benno Meyer-Rochow (2009) Bioluminescence in Focus – a collection of illuminating essays Research Signpost:
* Osamu Shimomura, Shimomura, Osamu (2006). ''Bioluminescence: Chemical Principles and Methods.'' Word Scientific Publishing. .
* Lee, John (2016). "Bioluminescence, the Nature of the Light." The University of Georgia Libraries. http://hdl.handle.net/10724/20031
*
*Anctil, Michel (2018). ''Luminous Creatures: The History and Science of Light Production in Living Organisms''. McGill-Queen's University Press.
External links
BBC: Red tide: Electric blue waves wash California shore
(video)
Smithsonian Ocean Portal: Bioluminescent animals photo gallery
National Geographic: Bioluminescence
Annual Review of Marine Science: Bioluminescence in the Sea
Canon Australia – Tips on How to Photograph Bioluminescence
* The New York City American Natural History Museum's "Creatures of Light: Nature's Bioluminescence" 2022 Featured Exhibit (in concert with the Ottawa, Canada-based Canadian Museum of Nature and Chicago's Field Museum of Natural History) webpage
{{good article
Bioluminescence,
Fisheries science
Light sources
Camouflage
Mimicry
Bioelectromagnetics