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{{Short description|Јужноамеричка електрична риба}}{{rut}}
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{{Speciesbox
| image = Electric-eel.jpg
| image_caption = Electric eel at the [[New England Aquarium]], United States
| image_width + 250px
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 11 November 2021">{{cite iucn |author=Reis, R. |author2=Lima, F. |date=2009 |title=''Electrophorus electricus'' |volume=2009 |page=e.T167700A6369863 |doi=10.2305/IUCN.UK.2009-2.RLTS.T167700A6369863.en |access-date=11 November 2021}}</ref>
| taxon = Electrophorus electricus
| authority = ([[Carl Linnaeus|Linnaeus]], 1766)
| synonyms = ''Gymnotus electricus''
}}
⚫
[[Слика:Electric-eel2.jpg|мини|250п|alt=Elektricna jegulja 1|Elektricna jegulja]]


'''Električna jegulja''' (''Electrophorus electricus'') je [[riba]] koja pripada porodici [[Gymnotidae]] iz reda [[Gymnotiformes]] ,a ne [[jegulje|jeguljama]] (red [[Anguilliformes]]) kako ime govori. It is a South American [[electric fish]]. Until the discovery of two additional species in 2019, the genus was classified as the [[monotypic]], with this species the only one in the genus.<ref name=Nature2019>{{cite journal | vauthors = de Santana CD, Crampton WG, Dillman CB, Frederico RG, Sabaj MH, Covain R, Ready J, Zuanon J, de Oliveira RR, Mendes-Júnior RN, Bastos DA, Teixeira TF, Mol J, Ohara W, Castro NC, Peixoto LA, Nagamachi C, Sousa L, Montag LF, Ribeiro F, Waddell JC, Piorsky NM, Vari RP, Wosiacki WB | display-authors = 6 | title = Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator | journal = Nature Communications | volume = 10 | issue = 1 | pages = 4000 | date = September 2019 | pmid = 31506444 | pmc = 6736962 | doi = 10.1038/s41467-019-11690-z | url = https://www.nature.com/articles/s41467-019-11690-z.pdf | access-date = 2019-09-10 | archive-url = https://web.archive.org/web/20190910170231/https://www.nature.com/articles/s41467-019-11690-z.pdf | bibcode = 2019NatCo..10.4000D | archive-date = 2019-09-10 | doi-access = free }}</ref> Despite the name, it is not an [[eel]], but rather a [[Gymnotiformes|knifefish]].<ref>{{Cite web|title=electric eel {{!}} Diet & Electric Shock {{!}} Britannica|url=https://www.britannica.com/animal/Electrophorus-fish-genus|access-date=2022-01-20|website=www.britannica.com|language=en}}</ref> It is considered as a freshwater [[teleost]] which contains an electrogenic tissue that produces electric discharges.<ref name=":0">{{Cite journal|last1=Mermelstein|first1=Claudia Dos Santos|last2=Costa|first2=Manoel Luis|last3=Moura Neto|first3=Vivaldo|date=September 2000|title=The cytoskeleton of the electric tissue of Electrophorus electricus, L.|journal=Anais da Academia Brasileira de Ciências| language=en| volume=72| issue=3| pages=341–351| doi=10.1590/S0001-37652000000300008 |pmid=11028099|issn=0001-3765|doi-access=free}}</ref>
'''Električna jegulja''' (''Electrophorus electricus'') je [[riba]] koja pripada porodici [[Gymnotidae]] iz reda [[Gymnotiformes]] ,a ne [[jegulje|jeguljama]] (red [[Anguilliformes]]) kako ime govori.


== Taksonomska istorija ==
⚫
[[Слика:Electric-eel2.jpg|мини|alt=Elektricna jegulja 1|Elektricna jegulja]]

The species is so unusual that it has been reclassified several times. When originally described by [[Carl Linnaeus]] in 1766, he used the name ''Gymnotus electricus'', placing it in the same genus as ''[[Gymnotus carapo]]'' (banded knifefish) which he had described several years earlier. It was only about a century later, in 1864, that the electric eel was moved to its own genus ''Electrophorus'' by [[Theodore Gill]].<ref>{{cite book | vauthors = Jordan DS | year=1963 | title=The Genera of Fishes and a Classification of Fishes |url=https://archive.org/details/generaoffishesan0000jord |url-access=registration | page=[https://archive.org/details/generaoffishesan0000jord/page/330 330] | publisher=Stanford University Press | author-link1 = David Starr Jordan }}</ref>

In September 2019, C. David de Santana et al. published work strongly suggesting a division of the genus into three species based on DNA divergence, ecology and habitat, anatomy and physiology, and electrical ability: ''E. electricus'', ''[[Electrophorus voltai|E. voltai]]'' sp. nov., and ''[[Electrophorus varii|E. varii]]'' sp. nov. The study found ''E. electricus'' to be the [[Sister group|sister species]] to ''E. voltai'', with both species diverging during the [[Pliocene]].<ref name=Nature2019/>


== Anatomija ==
== Anatomija ==
''Električna jegulja'' ima dugačko, cilindrično, zmijoliko telo sivo-smeđe boje, ponekad prošarano crvenom na donjem delu trupa. Nema krljušt, već joj je telo pokriveno debelom kožom i sluzi koja joj služi kao zaštita. Ima malu tupu glavu s velikim ustima, na koju se nastavlja do 2,75 metra dugačko tijelo, težine do 22 kg. Rep ''električne jegulje'' čini oko četiri petine njene ukupne dužine, na njemu se s donje strane nalaze njena jedina [[peraja]], kojima se kreće.
''Električna jegulja'' ima dugačko, cilindrično, zmijoliko telo sivo-smeđe boje, ponekad prošarano crvenom na donjem delu trupa. Nema krljušt, već joj je telo pokriveno debelom kožom i sluzi koja joj služi kao zaštita.<ref name="Albert, 2001">{{cite journal| vauthors = Albert JS |year= 2001|title=Species diversity and phylogenetic systematics of American knifefishes (Gymnotiformes, Teleostei)|journal=Misc. Publ.| issue=190| pages=1–127|hdl=2027.42/56433}}</ref> Ima malu tupu glavu s velikim ustima, na koju se nastavlja do 2,75 metra dugačko tijelo, težine do 22 kg. Rep ''električne jegulje'' čini oko četiri petine njene ukupne dužine, na njemu se s donje strane nalaze njena jedina [[peraja]], kojima se kreće. Ima slabo razvijene [[oko|oči]], i pretežno je noćna životinja.
Ima slabo razvijene [[oko|oči]], i pretežno je noćna životinja.


''Električne jegulje'' razvile su svoju sposobnost da [[Električna struja|strujom]] omame plen iz potrebe da zaštite svoja osetljiva usta od ozleda oštrih kostiju koje brojne [[Tropi|tropske]] ribe imaju. Omamljeni plen je nepokretan dovoljno dugo da ga ona proguta, bez žvakanja direktno u želudac. Ponekad se ''električna jegulja'' uopšte ne zamara da strujom omami plen, već ga munjevito zgrabi i počne gutati, pre nego što je on u stanju reagovati. Rep ''električne jegulje'' je onaj dio tela u kom ona ima [[Električna struja|električne]] [[Organ (anatomija)|organe]]. Oni su se razvili iz [[Mišići|mišićnog]] tkiva povezanih brojnim živcima sa [[kičma|kičmom]]. Oni mogu proizvesti [[električni napon|napon]] od 300-650 [[volt]]i, a to je dovoljno snažno da omami čak i ljude. Te organe one koriste i kao pomoć pri navigaciji i komuniciranju s drugim električnim jeguljama.
''Električne jegulje'' razvile su svoju sposobnost da [[Električna struja|strujom]] omame plen iz potrebe da zaštite svoja osetljiva usta od ozleda oštrih kostiju koje brojne [[Tropi|tropske]] ribe imaju. Omamljeni plen je nepokretan dovoljno dugo da ga ona proguta, bez žvakanja direktno u želudac. Ponekad se ''električna jegulja'' uopšte ne zamara da strujom omami plen, već ga munjevito zgrabi i počne gutati, pre nego što je on u stanju reagovati. Rep ''električne jegulje'' je onaj dio tela u kom ona ima [[Električna struja|električne]] [[Organ (anatomija)|organe]]. Oni su se razvili iz [[Mišići|mišićnog]] tkiva povezanih brojnim živcima sa [[kičma|kičmom]]. Oni mogu proizvesti [[električni napon|napon]] od 300-650 [[volt]]i, a to je dovoljno snažno da omami čak i ljude. Te organe one koriste i kao pomoć pri navigaciji i komuniciranju s drugim električnim jeguljama.


''Električna jegulja'' je lenjo stvorenje koja voli spore rečne tokove, gde izlazi na površinu svakih nekoliko minuta da ustima udahne vazduh. Usta električne jegulje bogata su krvnim žilama koje im omogućuju korišćenje usta kao [[pluća]]. Gotovo suvišne [[škrge]] koriste samo da uklone [[ugljen-dioksid|ugljen-dioksid]] iz krvi, a ne za [[kiseonik|kiseonik]].
''Električna jegulja'' je lenjo stvorenje koja voli spore rečne tokove, gde izlazi na površinu svakih nekoliko minuta da ustima udahne vazduh. Usta električne jegulje bogata su krvnim žilama koje im omogućuju korišćenje usta kao [[pluća]]. Gotovo suvišne [[škrge]] koriste samo da uklone [[ugljen-dioksid|ugljen-dioksid]] iz krvi, a ne za [[kiseonik|kiseonik]].<ref name="Boutilier, et. al. 1990">{{cite book| vauthors = Boutilier R |year=1990 |title=Vertebrate Gas Exchange: From Environment to Cell|series=Advances in Comparative & Environmental Physiology 6|publisher=Springer-Verlag Berlin|page=285|url=https://books.google.com/books?id=sfHxCAAAQBAJ&q=buccal%20cavity%20eel&pg=PA285|isbn= 9783642753800}}</ref> As obligate air-breathers, ''E. electricus'' must rise to the surface every ten minutes or so to inhale before returning to the bottom. Nearly eighty percent of the [[oxygen]] used by the fish is obtained in this way.<ref name="Johansen 1968">{{cite journal | vauthors = Johansen K, Lenfant C, Schmidt-Nielsen K, Petersen JA | title = Gas exchange and control of breathing in the electric eel, Electrophorus electricus. | journal = Zeitschrift für vergleichende Physiologie | date = June 1968 | volume = 61 | issue = 2 | pages = 137–63 |doi=10.1007/BF00341112 |s2cid=22364103 }}</ref>


[[Слика:Electric eel Electrophorus electricus.jpg|мини|лево|alt=Elektricna jegulja 2|Elektricna jegulja]]
[[Слика:Electric eel Electrophorus electricus.jpg|мини|лево|alt=Elektricna jegulja 2|Elektricna jegulja]]


''Električna jegulja'' pored riba jede i [[voće]] koje padne u vodu, pa na taj način služi kao pomagač u širenju semena, ali i kao čistač prašumskog ekosistema.
''Električna jegulja'' pored riba jede i [[voće]] koje padne u vodu, pa na taj način služi kao pomagač u širenju semena, ali i kao čistač prašumskog ekosistema.

== Rasprostranjenost ==
== Rasprostranjenost ==

''Električna jegulja'' je slatkovodna [[riba]], koja živi u mirnim delovima rečnih tokova siromašnim [[kiseonik|kiseonikom]], muljevitog dna, na severoistoku [[Južna Amerika|Južne Amerike]] od [[Brazil]]a, [[Venezuela|Venecuele]], [[Kolumbija|Kolumbije]] sve do [[Gvajana|Gvajane]]. ''Električna jegulja'' je jedna od glavnih grabljivica u [[Tropska kišna šuma|tropskim kišnim šumama]], gde čini više od 70% ukupne populacije riba.
''Električna jegulja'' je slatkovodna [[riba]], koja živi u mirnim delovima rečnih tokova siromašnim [[kiseonik|kiseonikom]], muljevitog dna, na severoistoku [[Južna Amerika|Južne Amerike]] od [[Brazil]]a, [[Venezuela|Venecuele]], [[Kolumbija|Kolumbije]] sve do [[Gvajana|Gvajane]]. ''Električna jegulja'' je jedna od glavnih grabljivica u [[Tropska kišna šuma|tropskim kišnim šumama]], gde čini više od 70% ukupne populacije riba.

== Izvori ==
== Fiziologija ==
{{further|Electric eel#Physiology}}
''E. electricus'' and other electric eels have three pairs of abdominal organs that produce electricity: the main organ, Hunter's organ, and Sachs' organ. These organs make up four fifths of its body, and give the electric eel the ability to generate two types of [[electric organ discharge]]s: low voltage and high voltage. These organs are made of [[electrocyte]]s, lined up so a current of ions can flow through them and stacked so each one adds to a potential difference.<ref name="PMC: PubMed Central">{{cite journal | vauthors = Xu J, Lavan DA | title = Designing artificial cells to harness the biological ion concentration gradient | journal = Nature Nanotechnology | volume = 3 | issue = 11 | pages = 666–70 | date = November 2008 | pmid = 18989332 | pmc = 2767210 | doi = 10.1038/nnano.2008.274 | bibcode = 2008NatNa...3..666X }}</ref> The three electrical organs are developed from muscle and exhibit several biochemical properties and morphological features of the muscle sarcolemma; they are found symmetrically along both sides of the eel.<ref name=":0" />

When the eel finds its prey, the brain sends a signal through the [[nervous system]] to the electrocytes. This opens the [[ion]] channels, allowing [[sodium]] to flow through, reversing the polarity momentarily. By causing a sudden difference in [[electric potential]], it generates an [[electric current]] in a manner similar to a [[Battery (electricity)|battery]], in which stacked plates each produce an electric potential difference.<ref name="PMC: PubMed Central"/> Electric eels are also capable of controlling their prey's nervous systems with their electrical abilities; by controlling their victim's nervous system and muscles via electrical pulses, they can keep prey from escaping or force it to move so they can locate its position.<ref>{{Cite news | url=https://www.bbc.com/news/science-environment-30335335 |title = Electric eels 'remotely control prey'|work = BBC News|date = 2014-12-04| vauthors = Gill V }}</ref><ref>{{Cite web | url=https://www.sciencenews.org/article/electric-eels-remote-control-nervous-systems-prey |title = Electric eels remote-control nervous systems of prey|date = 2015-02-17}}</ref>

[[Electric eel|Electric eels]] use electricity in multiple ways. Low voltages are used to sense the surrounding environment. High voltages are used to detect prey and, separately, stun them, at which point the electric eel applies a suction-feeding bite.<ref name=ShockAndAwe>{{cite journal| vauthors = Catania KC |title=Shock & Awe|journal=Science American|date=April 2019|volume=320|issue=4|pages=62–69}}</ref>
[[File:Electric organs.png|thumb|396x396px|Anatomy of an electric eel's organs that produce electricity]]
Sachs' organ is associated with [[electrolocation]]. Inside the organ are many muscle-like cells, called electrocytes. Each cell can only produce 0.15 V, though the organ can transmit a signal of nearly 10 V overall in amplitude at around 25&nbsp;Hz in frequency. These signals are emitted by the main organ; Hunter's organ can emit signals at rates of several hundred hertz.<ref name="Fishbase">{{FishBase|genus=Electrophorus|species=electricus|year=2005|month=December}} NOTE: Needs checking and updating if necessary - current version includes 2019 study.</ref>

There are several physiological differences among the three electric organs, which allow them to have very different functions. The main electrical organ and the strong-voltage section of Hunter's organ are rich in [[calmodulin]], a protein that is involved in high-voltage production.<ref>{{cite journal | vauthors = Traeger LL, Sabat G, Barrett-Wilt GA, Wells GB, Sussman MR | title = A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel | journal = Science Advances | volume = 3 | issue = 7 | pages = e1700523 | date = July 2017 | pmid = 28695212 | pmc = 5498108 | doi = 10.1126/sciadv.1700523 | bibcode = 2017SciA....3E0523T }}</ref> Additionally, the three organs have varying amounts of [[Sodium potassium ATPase|Na+/K+-ATPase]], which is a Na+/K+ ion pump that is crucial in the formation of voltage. The main and Hunter’s organs have a high expression of this protein, giving it a high sensitivity to changes in ion concentration, whereas Sachs' organ has a low expression of this protein.<ref>{{cite journal | vauthors = Ching B, Woo JM, Hiong KC, Boo MV, Choo CY, Wong WP, Chew SF, Ip YK | display-authors = 6 | title = Na+/K+-ATPase α-subunit (nkaα) isoforms and their mRNA expression levels, overall Nkaα protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus | journal = PLOS ONE | volume = 10 | issue = 3 | pages = e0118352 | date = 2015-03-20 | pmid = 25793901 | pmc = 4368207 | doi = 10.1371/journal.pone.0118352 | bibcode = 2015PLoSO..1018352C | doi-access = free }}</ref>

The typical output is sufficient to stun or deter virtually any animal. The eels can vary the intensity of the electric discharge, using lower discharges for hunting and higher intensities for stunning prey or defending themselves. They can also concentrate the discharge by curling up and making contact at two points along its body.<ref>{{cite journal | vauthors = Catania KC | title = Electric Eels Concentrate Their Electric Field to Induce Involuntary Fatigue in Struggling Prey | journal = Current Biology | volume = 25 | issue = 22 | pages = 2889–98 | date = November 2015 | pmid = 26521183 | doi = 10.1016/j.cub.2015.09.036 | doi-access = free }}</ref> When agitated, they can produce these intermittent electric shocks over at least an hour without tiring.

''E. electricus'' also possesses high frequency–sensitive tuberous receptors, which are distributed in patches over its body. This feature is apparently useful for hunting other Gymnotiformes.<ref name=Fishbase/> ''E. electricus'' has been used as a model in the study of [[bioelectrogenesis]].<ref name="Albert et al., 2008">{{cite journal| vauthors = Albert JS, Zakon HH, Stoddard PK, Unguez GA, Holmberg SK, Sussman MR |year= 2008|title= The case for sequencing the genome of the electric eel, Electrophorus electricus|journal=J. Fish Biol.|volume=72|issue=2|pages=331–354|doi=10.1111/j.1095-8649.2007.01631.x}}</ref> The species is of some interest to researchers, who make use of its [[acetylcholinesterase]] and [[adenosine triphosphate]].<ref name="AChE">{{cite journal | vauthors = Simon S, Massoulié J | title = Cloning and expression of acetylcholinesterase from Electrophorus. Splicing pattern of the 3' exons in vivo and in transfected mammalian cells | journal = The Journal of Biological Chemistry | volume = 272 | issue = 52 | pages = 33045–55 | date = December 1997 | pmid = 9407087 | doi = 10.1074/jbc.272.52.33045 | doi-access = free }}</ref><ref name="ATP">{{cite journal | vauthors = Zimmermann H, Denston CR | title = Adenosine triphosphate in cholinergic vesicles isolated from the electric organ of Electrophorus electricus | journal = Brain Research | volume = 111 | issue = 2 | pages = 365–76 | date = July 1976 | pmid = 949609 | doi = 10.1016/0006-8993(76)90780-0 | s2cid = 5619963 }}</ref>

== Reference ==
{{izvori}}
{{izvori}}

== Literatura ==
{{refbegin|30em}}
* {{cite journal | vauthors = Catania K | title = The shocking predatory strike of the electric eel | journal = Science | location = New York, N.Y. | volume = 346 | issue = 6214 | pages = 1231–4 | date = December 2014 | pmid = 25477462 | doi = 10.1126/science.1260807 | bibcode = 2014Sci...346.1231C | s2cid = 14371418 }}
* {{cite journal | vauthors = Catania KC | title = Leaping eels electrify threats, supporting Humboldt's account of a battle with horses | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 113 | issue = 25 | pages = 6979–84 | date = June 2016 | pmid = 27274074 | pmc = 4922196 | doi = 10.1073/pnas.1604009113 | doi-access = free }}
* {{cite journal | vauthors = Catania KC | title = Power Transfer to a Human during an Electric Eel's Shocking Leap | journal = Current Biology | volume = 27 | issue = 18 | pages = 2887–2891.e2 | date = September 2017 | pmid = 28918950 | doi = 10.1016/j.cub.2017.08.034 | doi-access = free }}
* {{cite journal | vauthors = Finger S | title = Dr. Alexander Garden, a Linnaean in colonial America, and the saga of five "electric eels" | journal = Perspectives in Biology and Medicine | volume = 53 | issue = 3 | pages = 388–406 | date = 2010 | pmid = 20639607 | doi = 10.1353/pbm.0.0163 | s2cid = 8544900 }}
* {{cite journal | vauthors = Gervais R | year = 2017| title = Phenomenological Understanding and Electric Eels | url = http://www.ehu.eus/ojs/index.php/THEORIA/article/download/17294/15727 | journal = Theoria | volume = 32 | issue = 3| pages = 293–302 | doi = 10.1387/theoria.17294 | doi-access = free }}
* {{cite journal | vauthors = Traeger LL, Sabat G, Barrett-Wilt GA, Wells GB, Sussman MR | title = A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel | journal = Science Advances | volume = 3 | issue = 7 | pages = e1700523 | date = July 2017 | pmid = 28695212 | pmc = 5498108 | doi = 10.1126/sciadv.1700523 | bibcode = 2017SciA....3E0523T }}
{{refend}}

== Spoljašnje veze ==
{{Commonscat|Electrophorus electricus}}
{{Commonscat|Electrophorus electricus}}
*{{Wikispecies-inline|Electrophorus electricus}}
http://www.britannica.com/EBchecked/topic/182547/electric-eel
* [https://archive.org/details/electric_eel 1954 educational film about the electric eel] from the [[Moody Institute of Science]]

{{Taxonbar|from=Q201235}}

[[Категорија:Рибе Јужне Америке]]
[[Категорија:Рибе Јужне Америке]]
[[Категорија:Рибе Бразила]]
[[Категорија:Рибе Бразила]]

Верзија на датум 22. мај 2022. у 19:23

Električna jegulja
Electric eel at the New England Aquarium, United States
Научна класификација уреди
Домен: Eukaryota
Царство: Animalia
Тип: Chordata
Класа: Actinopterygii
Ред: Gymnotiformes
Породица: Gymnotidae
Род: Electrophorus
Врста:
E. electricus
Биномно име
Electrophorus electricus
(Linnaeus, 1766)
Синоними

Gymnotus electricus

Elektricna jegulja 1
Elektricna jegulja

Električna jegulja (Electrophorus electricus) je riba koja pripada porodici Gymnotidae iz reda Gymnotiformes ,a ne jeguljama (red Anguilliformes) kako ime govori. It is a South American electric fish. Until the discovery of two additional species in 2019, the genus was classified as the monotypic, with this species the only one in the genus.[2] Despite the name, it is not an eel, but rather a knifefish.[3] It is considered as a freshwater teleost which contains an electrogenic tissue that produces electric discharges.[4]

Taksonomska istorija

The species is so unusual that it has been reclassified several times. When originally described by Carl Linnaeus in 1766, he used the name Gymnotus electricus, placing it in the same genus as Gymnotus carapo (banded knifefish) which he had described several years earlier. It was only about a century later, in 1864, that the electric eel was moved to its own genus Electrophorus by Theodore Gill.[5]

In September 2019, C. David de Santana et al. published work strongly suggesting a division of the genus into three species based on DNA divergence, ecology and habitat, anatomy and physiology, and electrical ability: E. electricus, E. voltai sp. nov., and E. varii sp. nov. The study found E. electricus to be the sister species to E. voltai, with both species diverging during the Pliocene.[2]

Anatomija

Električna jegulja ima dugačko, cilindrično, zmijoliko telo sivo-smeđe boje, ponekad prošarano crvenom na donjem delu trupa. Nema krljušt, već joj je telo pokriveno debelom kožom i sluzi koja joj služi kao zaštita.[6] Ima malu tupu glavu s velikim ustima, na koju se nastavlja do 2,75 metra dugačko tijelo, težine do 22 kg. Rep električne jegulje čini oko četiri petine njene ukupne dužine, na njemu se s donje strane nalaze njena jedina peraja, kojima se kreće. Ima slabo razvijene oči, i pretežno je noćna životinja.

Električne jegulje razvile su svoju sposobnost da strujom omame plen iz potrebe da zaštite svoja osetljiva usta od ozleda oštrih kostiju koje brojne tropske ribe imaju. Omamljeni plen je nepokretan dovoljno dugo da ga ona proguta, bez žvakanja direktno u želudac. Ponekad se električna jegulja uopšte ne zamara da strujom omami plen, već ga munjevito zgrabi i počne gutati, pre nego što je on u stanju reagovati. Rep električne jegulje je onaj dio tela u kom ona ima električne organe. Oni su se razvili iz mišićnog tkiva povezanih brojnim živcima sa kičmom. Oni mogu proizvesti napon od 300-650 volti, a to je dovoljno snažno da omami čak i ljude. Te organe one koriste i kao pomoć pri navigaciji i komuniciranju s drugim električnim jeguljama.

Električna jegulja je lenjo stvorenje koja voli spore rečne tokove, gde izlazi na površinu svakih nekoliko minuta da ustima udahne vazduh. Usta električne jegulje bogata su krvnim žilama koje im omogućuju korišćenje usta kao pluća. Gotovo suvišne škrge koriste samo da uklone ugljen-dioksid iz krvi, a ne za kiseonik.[7] As obligate air-breathers, E. electricus must rise to the surface every ten minutes or so to inhale before returning to the bottom. Nearly eighty percent of the oxygen used by the fish is obtained in this way.[8]

Elektricna jegulja 2
Elektricna jegulja

Električna jegulja pored riba jede i voće koje padne u vodu, pa na taj način služi kao pomagač u širenju semena, ali i kao čistač prašumskog ekosistema.

Rasprostranjenost

Električna jegulja je slatkovodna riba, koja živi u mirnim delovima rečnih tokova siromašnim kiseonikom, muljevitog dna, na severoistoku Južne Amerike od Brazila, Venecuele, Kolumbije sve do Gvajane. Električna jegulja je jedna od glavnih grabljivica u tropskim kišnim šumama, gde čini više od 70% ukupne populacije riba.

Fiziologija

За више информација погледајте: Electric eel § Physiology

E. electricus and other electric eels have three pairs of abdominal organs that produce electricity: the main organ, Hunter's organ, and Sachs' organ. These organs make up four fifths of its body, and give the electric eel the ability to generate two types of electric organ discharges: low voltage and high voltage. These organs are made of electrocytes, lined up so a current of ions can flow through them and stacked so each one adds to a potential difference.[9] The three electrical organs are developed from muscle and exhibit several biochemical properties and morphological features of the muscle sarcolemma; they are found symmetrically along both sides of the eel.[4]

When the eel finds its prey, the brain sends a signal through the nervous system to the electrocytes. This opens the ion channels, allowing sodium to flow through, reversing the polarity momentarily. By causing a sudden difference in electric potential, it generates an electric current in a manner similar to a battery, in which stacked plates each produce an electric potential difference.[9] Electric eels are also capable of controlling their prey's nervous systems with their electrical abilities; by controlling their victim's nervous system and muscles via electrical pulses, they can keep prey from escaping or force it to move so they can locate its position.[10][11]

Electric eels use electricity in multiple ways. Low voltages are used to sense the surrounding environment. High voltages are used to detect prey and, separately, stun them, at which point the electric eel applies a suction-feeding bite.[12]

Anatomy of an electric eel's organs that produce electricity

Sachs' organ is associated with electrolocation. Inside the organ are many muscle-like cells, called electrocytes. Each cell can only produce 0.15 V, though the organ can transmit a signal of nearly 10 V overall in amplitude at around 25 Hz in frequency. These signals are emitted by the main organ; Hunter's organ can emit signals at rates of several hundred hertz.[13]

There are several physiological differences among the three electric organs, which allow them to have very different functions. The main electrical organ and the strong-voltage section of Hunter's organ are rich in calmodulin, a protein that is involved in high-voltage production.[14] Additionally, the three organs have varying amounts of Na+/K+-ATPase, which is a Na+/K+ ion pump that is crucial in the formation of voltage. The main and Hunter’s organs have a high expression of this protein, giving it a high sensitivity to changes in ion concentration, whereas Sachs' organ has a low expression of this protein.[15]

The typical output is sufficient to stun or deter virtually any animal. The eels can vary the intensity of the electric discharge, using lower discharges for hunting and higher intensities for stunning prey or defending themselves. They can also concentrate the discharge by curling up and making contact at two points along its body.[16] When agitated, they can produce these intermittent electric shocks over at least an hour without tiring.

E. electricus also possesses high frequency–sensitive tuberous receptors, which are distributed in patches over its body. This feature is apparently useful for hunting other Gymnotiformes.[13] E. electricus has been used as a model in the study of bioelectrogenesis.[17] The species is of some interest to researchers, who make use of its acetylcholinesterase and adenosine triphosphate.[18][19]

Reference

  1. ^ Reis, R.; Lima, F. (2009). „Electrophorus electricus”. Црвени списак угрожених врста IUCN. IUCN. 2009: e.T167700A6369863. doi:10.2305/IUCN.UK.2009-2.RLTS.T167700A6369863.en Слободан приступ. Приступљено 11. 11. 2021. 
  2. ^ а б de Santana CD, Crampton WG, Dillman CB, Frederico RG, Sabaj MH, Covain R, et al. (септембар 2019). „Unexpected species diversity in electric eels with a description of the strongest living bioelectricity generator” (PDF). Nature Communications. 10 (1): 4000. Bibcode:2019NatCo..10.4000D. PMC 6736962 Слободан приступ. PMID 31506444. doi:10.1038/s41467-019-11690-z Слободан приступ. Архивирано из оригинала (PDF) 2019-09-10. г. Приступљено 2019-09-10. 
  3. ^ „electric eel | Diet & Electric Shock | Britannica”. www.britannica.com (на језику: енглески). Приступљено 2022-01-20. 
  4. ^ а б Mermelstein, Claudia Dos Santos; Costa, Manoel Luis; Moura Neto, Vivaldo (септембар 2000). „The cytoskeleton of the electric tissue of Electrophorus electricus, L.”. Anais da Academia Brasileira de Ciências (на језику: енглески). 72 (3): 341—351. ISSN 0001-3765. PMID 11028099. doi:10.1590/S0001-37652000000300008 Слободан приступ. 
  5. ^ Jordan DS (1963). The Genera of Fishes and a Classification of FishesНеопходна слободна регистрација. Stanford University Press. стр. 330. 
  6. ^ Albert JS (2001). „Species diversity and phylogenetic systematics of American knifefishes (Gymnotiformes, Teleostei)”. Misc. Publ. (190): 1—127. hdl:2027.42/56433. 
  7. ^ Boutilier R (1990). Vertebrate Gas Exchange: From Environment to Cell. Advances in Comparative & Environmental Physiology 6. Springer-Verlag Berlin. стр. 285. ISBN 9783642753800. 
  8. ^ Johansen K, Lenfant C, Schmidt-Nielsen K, Petersen JA (јун 1968). „Gas exchange and control of breathing in the electric eel, Electrophorus electricus.”. Zeitschrift für vergleichende Physiologie. 61 (2): 137—63. S2CID 22364103. doi:10.1007/BF00341112. 
  9. ^ а б Xu J, Lavan DA (новембар 2008). „Designing artificial cells to harness the biological ion concentration gradient”. Nature Nanotechnology. 3 (11): 666—70. Bibcode:2008NatNa...3..666X. PMC 2767210 Слободан приступ. PMID 18989332. doi:10.1038/nnano.2008.274. 
  10. ^ Gill V (2014-12-04). „Electric eels 'remotely control prey'”. BBC News. 
  11. ^ „Electric eels remote-control nervous systems of prey”. 2015-02-17. 
  12. ^ Catania KC (април 2019). „Shock & Awe”. Science American. 320 (4): 62—69. 
  13. ^ а б Froese, Rainer; Pauly, Daniel; ур. (2005). Electrophorus electricus” на FishBase-у. [верзија на датум: December 2005] NOTE: Needs checking and updating if necessary - current version includes 2019 study.
  14. ^ Traeger LL, Sabat G, Barrett-Wilt GA, Wells GB, Sussman MR (јул 2017). „A tail of two voltages: Proteomic comparison of the three electric organs of the electric eel”. Science Advances. 3 (7): e1700523. Bibcode:2017SciA....3E0523T. PMC 5498108 Слободан приступ. PMID 28695212. doi:10.1126/sciadv.1700523. 
  15. ^ Ching B, Woo JM, Hiong KC, Boo MV, Choo CY, Wong WP, et al. (2015-03-20). „Na+/K+-ATPase α-subunit (nkaα) isoforms and their mRNA expression levels, overall Nkaα protein abundance, and kinetic properties of Nka in the skeletal muscle and three electric organs of the electric eel, Electrophorus electricus”. PLOS ONE. 10 (3): e0118352. Bibcode:2015PLoSO..1018352C. PMC 4368207 Слободан приступ. PMID 25793901. doi:10.1371/journal.pone.0118352 Слободан приступ. 
  16. ^ Catania KC (новембар 2015). „Electric Eels Concentrate Their Electric Field to Induce Involuntary Fatigue in Struggling Prey”. Current Biology. 25 (22): 2889—98. PMID 26521183. doi:10.1016/j.cub.2015.09.036 Слободан приступ. 
  17. ^ Albert JS, Zakon HH, Stoddard PK, Unguez GA, Holmberg SK, Sussman MR (2008). „The case for sequencing the genome of the electric eel, Electrophorus electricus”. J. Fish Biol. 72 (2): 331—354. doi:10.1111/j.1095-8649.2007.01631.x. 
  18. ^ Simon S, Massoulié J (децембар 1997). „Cloning and expression of acetylcholinesterase from Electrophorus. Splicing pattern of the 3' exons in vivo and in transfected mammalian cells”. The Journal of Biological Chemistry. 272 (52): 33045—55. PMID 9407087. doi:10.1074/jbc.272.52.33045 Слободан приступ. 
  19. ^ Zimmermann H, Denston CR (јул 1976). „Adenosine triphosphate in cholinergic vesicles isolated from the electric organ of Electrophorus electricus”. Brain Research. 111 (2): 365—76. PMID 949609. S2CID 5619963. doi:10.1016/0006-8993(76)90780-0. 

Literatura

Spoljašnje veze

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