Luminous organ

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Luminous organs of the deep-sea fish Photostomias guernei

As light organs or Photophore in the are Biology all organs referred to, which are able to light to produce. The term photophore ( ancient Greek φῶς phos “light” and φορεύς phoreus “carrier”) literally means “carrier of light” and is therefore also applied to cellular light sources, ie not organized in organs or tissues. Luminous organs occur in a large number of living beings (especially marine ones) that can be functionally grouped as luminous organisms. What they all have in common is that they release part of the energy available to them in the form of light, which is known as bioluminescence . The light is either produced in specially designed organs or is created with the help of symbiotic luminous bacteria, which can also be concentrated on certain organs (mainly in fish and some cephalopods ).

Bioluminescence

The phenomenon of bioluminescence is shown by different organisms, which include both unicellular and multicellular ones. The ability to emit light was developed several times independently of one another in living beings , the respective bioluminescent systems within the cells are molecularly different, the corresponding genes are not homologous with one another . But they are all based on a similar basic biochemical principle.

It is based on putting a molecule of a luciferin into an unstable excited state by chemical action , which changes into another stable state when light is emitted. The binding of the respective luciferin to a particular protein is decisive for the effect; this can be an enzymatically acting luciferase or the photoprotein aequorin .

The luciferin molecule changed by the bioluminescent reaction must then be exchanged for a new one. The reaction cycle is connected with an oxidation and leads to the decarboxylation of the luciferin, which is regenerated again using chemical energy. Depending on the specific molecular structure of the converted luciferin and the protein involved, as well as other factors, some of which are still unknown, the wavelength of the emitted light is different, of different color.

Demarcation

Bioluminescence has developed in parallel in several realms :

Luminous bacteria, dinoflagellates (protozoa) and unicellular plants consist of a single cell, so they have no organs. In the case of mushrooms, lighting effects are not localized in individual parts of the body or organs, so the term lighting organ is also not applicable here. Instead, such luminescence in subcellular cell structures is usually referred to as photosomes and scintillons . Therefore, only in animals are we talking about luminous organs.

Animal groups

At least 30 parallel evolutions of luminous organs can be distinguished in different animal phyla . These include some of the organisms

The recording of all animals with luminous organs is still incomplete.

Annelid worms

Many marine annelids have luminous organs.

Among the Wenigborstern (Oligochaeta) that includes Pontodrilus .

Among the Vielborstern (Polychaeta) some tube worms the Cirratulidae , Terebellidae and Chaetopterus as chaetopterus variopedatus , the luminous mucus likely produce for defense. Chaetopterus can literally throw him out. Also Gastrolepidia like cucumbers shed worm ( Gastrolepidia clavigera ) and Sylliden as Odontosyllis can emit intermittent luminous substance. With Odontosyllis phosphorea , this is also used for partner communication.

Crustaceans

Luminous crab Meganyctiphanes norvegica ( krill )

Among the crustaceans possess some ostracods , copepods (Copepoda), amphipods (amphipods), krill (Euphausiacea) mysida (Mysid) and decapods (Decapoda) light organs.

Many mussel crabs of the genus Vargula (e.g. Vargula hilgendorfii ) can give off luminous clouds for defense. In Vargula also exists sexual dimorphism : Often only one male at dusk short light pulses from, umschwommen of non-luminous male. With Vargula graminicola , all males can emit very short flashes of light (280 ms ) synchronously  .

insects

Luminous organ in the female of the great firefly

Among the insects some beetles (Coleoptera), u. a. Fireflies or glowworms (Lampyridae) and lightning beetles (of the genera Cucujo and Pyrophorus ), luminous organs. Some dipteras are also bioluminescent, as are some species of longhorn mosquitoes (Keroplatidae), e.g. B. the New Zealand glowworm ( Arachnocampa luminosa ).

The fireflies, e.g. B. Phrixotrix hirtus are among the best studied animals with a luminous organ. With them, the biochemical reaction is based on the oxidation of luciferin by the enzyme luciferase ( EC  1.13.12.5 ), which evolved from a coenzyme A synthase , an AMP-CoA ligase . The bioluminescent phenomena of fireflies are not uniform, different fluorescent colors can be produced among different species of beetle and sometimes within the same species .

The pointed head cicadas (Fulgoromorpha), on the other hand, also called lantern bearer-like, from the order of the Schnabelkerfe (Hemiptera), often have a conspicuous head extension and were named after the lantern bearer ( Fulgora laternaria ); however, they do not have any luminous organs like this one to which it was mistakenly ascribed in the 17th century.

Cephalopods

Vampire squid ( Vampyroteuthis infernalis ), the miracle lamps ( Lycoteuthis ) and other squids ( Theutida ), especially of the deep sea, have luminous organs, as do the females of the octopus from the Bolitaenidae family .

fishes

Members of at least 21 marine fish families from 7 orders harbor symbiotic luminous bacteria in luminous organs. These are housed in anatomically different organs, which indicates analogous developments. Typically, members of a fish family only harbor the same species of luminescent bacteria.

Four symbiotic luminous bacteria from luminous organs of fish were isolated:

Many fish have strong pigmentation due to melanin deposits in the peritoneal area and their stomach . The function of this pigmentation is likely to suppress tell-tale luminescence from their food or their endosymbiotic gut bacteria.

Functions

The glow is to be regarded as an expression of life - like sounds and color - as well as in the context of behavior .

Sea lights

In marine animals, light organs help to fulfill vital functions (for intra-species communication, reproduction , attracting prey and defense). Another function of camouflage is to make your own shadow invisible from below. Since light distribution and intensity are extremely critical for this camouflage purpose, some animals of the medium depth, such as sharks from the subfamily of lantern sharks (Etmopterinae), e.g. B. the lesser black dogfish ( Etmopterus spinax ) hormonally controlled pigmented and shape-changing chromatophores to cover their finely distributed light sources and thus constantly adapt to the lighting conditions. This is a form of shape-resolution camouflage ( Somatolyse ), not the mimicry , which mimics inanimate forms.

A particularly beautiful natural spectacle is the glow of the sea by various light organisms in the sea, which can use it to organize large swarms. This can be bioluminescence from photosomes of single cells (dinoflagellates such as Noctiluca ) or from luminous organs of luminous jellyfish or luminous crabs (krill).

Insect communication

In the case of fireflies, the communication effect through lights was examined.

Single receipts

  1. ^ A b c Steven HD Haddock, Mark A. Moline, James F. Case: Bioluminescence in the sea. In: Marine Science . Volume 2, 2010, doi : 10.1146 / annurev-marine-120308-081028 (contains a " cladogram of bioluminescence").
  2. ^ JAC Nicol: The luminescence of fishes. In: Symp. Zool. Soc. Lond. Volume 19, 1967.
  3. ^ A b c Thérèse Wilson, J. Woodland Hastings: Bioluminescence. In: Annual Review of Cell and Developmental Biology. Volume 14, No. 1, 1998, pp. 197-230, doi : 10.1146 / annurev.cellbio.14.1.197 .
  4. ↑ a b c d e f Keith V. Wood: The chemical mechanism and evolutionary development of beetle bioluminescence. In: Photochemistry and Photobiology. Volume 62, No. 4, 1995, pp. 662-673, doi : 10.1111 / j.1751-1097.1995.tb08714.x .
  5. ^ DE Desjardin, AG Oliveira, CV Stevani: Fungi bioluminescence revisited. In: Photochem Photobiol Sci. Volume 7, No. 2, 2008, pp. 170-182, doi : 10.1039 / b713328f , PMID 18264584 .
  6. ↑ Peter J. Herring: Systematic distribution of bioluminescence in living organisms. In: Journal of bioluminescence and chemiluminescence . Volume 1, No. 3, 1987, pp. 147-163, doi : 10.1002 / bio.1170010303 .
  7. ↑ a b c d e f g h i j k Peter J. Herring: Bioluminescent communication in the sea. In: Peter J. Herring (Ed.): Light and Life in the Sea. Cambridge University Press, Cambridge (1990), pp. 245-264.
  8. ↑ VR Viviani, RA Prado, DR Neves, D. Kato, JA Barbosa: A route from darkness to light: emergence and evolution of luciferase activity in AMP-CoA-ligases inferred from a mealworm luciferase-like enzyme. In: Biochemistry. Volume 52, No. 23, 2013, pp. 3963-3973, doi : 10.1021 / bi400141u .
  9. ^ BW Ridout: Structure, form and function of the lantern fly head process. Unpublished thesis, 1983, Birbeck college. Quoted in:
    Geert Goemans: The fulgoridae (Hemiptera, Fulgoromorpha) of Guatemala. In: Biodiversidad de Guatemala . Volume 1, 2006, pp. 337-344.
  10. ↑ a b c d e f Paul V. Dunlap et al: Inception of formation and early morphogenesis of the bacterial light organ of the sea urchin cardinalfish, Siphamia versicolor. In: Marine Biology. Volume 156, No. 10, 2009, pp. 2011-2020.
  11. ^ A b Peter J. Herring: Marine ecology and natural products. In: Pure Appl. Chem. Vol. 51, No. 9, 1979, pp. 1901-1911.
  12. ↑ a b Julien M. Claes, Jérôme Mallefet: The lantern shark's light switch: turning shallow water crypsis into midwater camouflage. In: Biology Letters. Volume 6, No. 5, 2010, pp. 685-687.
  13. ↑ James E. Lloyd: Bioluminescent communication in insects. In: Annual Review of Entomology. Volume 16, No. 1, 1971, pp. 97-122, doi : 10.1146 / annurev.en.16.010171.000525 .
  14. ↑ James E. Lloyd: Bioluminescence and communication in insects. In: Annual Review of Entomology. Volume 28, 1983, pp. 131-160, doi : 10.1146 / annurev.en.28.010183.001023 .

literature

  • EN Harvey: Bioluminescence: evolution and comparative biochemistry. In: Federation Proceedings. Vol. 12. No. 2, 1953, pp. 597-606, PMID 13060362 .