Agkistrodon: Difference between revisions
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==Venom== |
==Venom== |
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Pit vipers of the genus ''Agkistrodon'' rely on a potent [[venom]] they produce for their survival. Used to immobilize [[prey]] and fend off [[Predation|predators]], one bite can inject enough venom into a human to cause severe pain, swelling, weakness, difficulty breathing, hemorrhaging, gangrene, fever, vomiting, and in rare instances, even death.<ref name="source eleven">"Agkistrodon acutus pit vipers." Medical-Explorer.com; accessed April 2010. [http://www.medical-explorer.com/medicinal-ingredients-a/agkistrodon-acutus_1.html]</ref> |
Pit vipers of the genus ''Agkistrodon'' rely on a potent [[venom]] they produce for their survival. Used to immobilize [[prey]] and fend off [[Predation|predators]], one bite can inject enough venom into a human to cause severe pain, swelling, weakness, difficulty breathing, hemorrhaging, gangrene, fever, vomiting, and in rare instances, even death.<ref name="source eleven">"Agkistrodon acutus pit vipers." Medical-Explorer.com; accessed April 2010. [http://www.medical-explorer.com/medicinal-ingredients-a/agkistrodon-acutus_1.html]</ref> |
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The venom of all three species is assumed to be not unlike that of ''A. contortrix'', which contains thrombin-like enzymes that act upon the coagulant activity of the blood. A study of [[Electrophoresis|electrophoretic]] patterns of proteins in venoms among and within populations of ''A. contortrix'' and ''A. piscivorus'' showed that substantial variation exists,<ref name=Jones1976/> and no |
The venom of all three species is assumed to be not unlike that of ''A. contortrix'', which contains thrombin-like enzymes that act upon the coagulant activity of the blood. A study of [[Electrophoresis|electrophoretic]] patterns of proteins in venoms among and within populations of ''A. contortrix'' and ''A. piscivorus'' showed that substantial variation exists,<ref name=Jones1976/> and no reason exists to believe that these differences do not correspond with variations in toxicity.<ref name="C&L04"/> |
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===Research=== |
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In a study conducted at the [[University of Florida College of Medicine|College of Medicine]] at the [[University of Florida]], venom from ''A. piscivorous'' was injected into the [[lymph fluid]] of a [[frog]]. The frog immediately suffocated because of the collapse of its lung sacs. The venom even resulted in lung constriction when directly applied to the surface of the frog's lungs. To test this, trace amounts of venom were dropped onto a single pulmonary sac in a frog's lung after it was anesthetized and its chest cavity dissected open. A drop of solution containing a venom concentration of 1 mg/ml was enough to cause contraction of the [[pulmonary artery]] adventitia after 5-8 sec in a frog weighing 40 g.<ref name="frog">{{cite journal |vauthors=Gennaro JF, Hall HP, Casey ER, Hayes WK |title=Neurotropic effects of venoms and other factors that promote prey acquisition |journal=Journal of Experimental Zoology. Part a, Ecological Genetics and Physiology |volume=307 |issue=9 |pages=488–99 |date=September 2007 |pmid=17620305 |doi=10.1002/jez.405}}</ref> The study found, however, that this toxic effect is simply a tool the snake can choose to employ from an accessory venom gland it has. In most instances, the viper injects a venom that tends to immobilize, not kill, its prey before [[ingestion]]. In this case, the main venom glands secrete a toxin that inhibits the prey’s sympathetic response to [[Fight-or-flight response|flee or fend off]] its predator. This essentially stuns the animal so that the predator can easily attack.<ref name="frog"/> |
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===Venom and cancer treatment=== |
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Although ''Agkistrodon'' venom is lethal to both prey and humans ''in vivo'', when controlled, the venom has some clinical application. ''D. acutus'' snake venom contains a protein called ACTX-6.<ref name="Fas">{{cite journal |vauthors=Zhang L, Cui L |title=A cytotoxin isolated from ''Deinagkistrodon acutus'' snake venom induces apoptosis via Fas pathway in A549 cells |journal=Toxicology in Vitro |volume=21 |issue=6 |pages=1095–103 |date=September 2007 |pmid=17544616 |doi=10.1016/j.tiv.2007.04.008}}</ref> This protein was shown to induce [[apoptosis]] (cell death) in isolated [[cancer cells]] through Fas pathway activation.<ref name="Fas"/> Fas is a protein that becomes a death receptor in the [[cellular membrane]]. When activated, Fas turns on what is called a “caspase cascade.”<ref name="cancer bio book">Weinberg, Robert A. The Biology of Cancer. Garland Science, Taylor and Francis Group.(2007);343-350. {{ISBN|0-8153-4078-8}}.</ref> This pathway is made up of a series of proteins called initiator and executioner caspases. Initiator caspases help form an apoptosis initiation factor that eventually activates executioner caspases (see figure 3). Executioner caspases go on to “digest” the cell from the inside out. They cleave [[cytoskeleton]] filaments and [[DNA]] until the cell completely implodes.<ref name="cancer bio book"/> |
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If this pathway can be activated in tumor cells using ''Agkistrodon'' venom, then theoretically, the proteins in the venom could be used to target and kill cancerous cells. |
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===Venom and traditional Chinese medicine=== |
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''D. acutus'' venom has been used in traditional Chinese medicine for centuries to extract [[antivenin]] that is successfully used to treat snakebites.<ref name="thrombosis">{{cite journal |vauthors=Chen JH, Liang XX, Qiu PX, Yan GM |title=Thrombolysis effect with FIIa from Agkistrodon acutus venom in different thrombosis model |journal=Acta Pharmacologica Sinica |volume=22 |issue=5 |pages=420–2 |date=May 2001 |pmid=11743889}}</ref><ref name="venom gland">{{cite journal |author=Qinghua L |title=A catalog for transcripts in the venom gland of the ''Agkistrodon acutus'': identification of the toxins potentially involved in coagulopathy |journal=Biochemical and Biophysical Research Communications |volume=341 |issue=2 |pages=522–31 |date=March 2006 |pmid=16438937 |doi=10.1016/j.bbrc.2006.01.006 |name-list-format=vanc |author2=Xiaowei Z |author3=Wei Y |display-authors=3 |last4=Chenji |first4=Li |last5=Yijun |first5=Huang |last6=Pengxin |first6=Qiu |last7=Xingwen |first7=Su |last8=Songnian |first8=Hu |last9=Guangmei |first9=Yan}}</ref> Different parts of the snake are also prescribed to help alleviate ailments known as “wind diseases.”<ref name="thrombosis"/> Because these snakes move so quickly, substances from their bodies are thought to easily treat these fast-moving “wind” syndromes. ''D. acutus'' is currently used in patients with [[arthritis]], [[leprosy]], [[tetanus]], [[boils]], and, as previously mentioned, tumors.<ref>Subhuti Dharmananda, Ph.D. The Medicinal Use of Snakes in China. Institute for Traditional Medicine, Portland, Oregon. May 1997 [http://www.itmonline.org/arts/snakes.htm]</ref> The same qualities that make snakes flexible, capable of regenerating skin, and able to inflict [[paralysis]] could be transferred to human conditions if applied medicinally.<ref name="source eleven"/> The vipers are prepared by cooking the flesh of the headless body, grinding a paste of snake ash and mixing it with [[honey]], drying the snake and compacting it into a powder, or even injecting their venom [[intravenously]].<ref name="source eleven"/> Although these practices are common in Chinese medicine, no current studies have affirmed the effectiveness of these treatments. Whether or not these "cures" simply have a [[placebo effect]] or actually heal the patients is not known. |
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==Species== |
==Species== |
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Revision as of 22:10, 8 August 2019
| Agkistrodon | |
|---|---|
| |
| Copperhead, A. contortrix | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Suborder: | Serpentes |
| Family: | Viperidae |
| Subfamily: | Crotalinae |
| Genus: | Agkistrodon Palisot de Beauvois, 1799 |
| Synonyms | |
Agkistrodon is a genus of venomous pit vipers found in North America from the United States south to northern Costa Rica.[1] Six species are currently recognized,[2] all of them polytypic and closely related.[3] Common names include: cottonmouths, copperheads, and cantils.[4] Some varieties are known as "moccasins" or "moccasin snakes", such as Agkistrodon piscivorus, the water moccasin.
Name origin
The name Agkistrodon comes from the Greek words agkistron (ἄγκιστρον, 'fishhook', with the irregular transliteration gk rather than the usual nk) and odous (ὁδοὐς, 'tooth,' from the stem ὁδόντ-) and is likely a reference to the fangs.[4]
Some varieties of the genus are given the common name "moccasin" or "moccasin snake" in the United States, which is the Algonquian word for "shoe". The origin of this nickname are unknown. The first known use of "moccasin" to refer to a deadly venomous snake was in a 1765 publication. The nickname is used to refer to both cottonmouths and copperheads. According to the Word Detective, this use may be related to their color and appearance or the silence with which they move.[5] Another source for this name may be the Native American word "mokesoji" of unknown origin and meaning.[6]
Description
Members of this genus have a number of features in common. All species have a relatively broad head with short fangs. A loreal scale is present, except in A. piscivorus. Usually, nine large symmetrical platelike scales are on the crown of the head, but in all species, these are often irregularly fragmented or have sutures, especially in A. bilineatus. All have a sharply defined canthus rostralis and a vertically elliptical pupil. Usually eight (6-10) supralabial scales and usually 10-11 (8-13) sublabials are present. The dorsal scales are mostly keeled and at midbody number 21-25 (usually 23), while A. piscivorus has 23-27 (usually 25). The snake has 127-157 ventral scales and 36-71 subcaudals. Of the latter, some may be divided. The anal scale is single. All have a color pattern of 10-20 dark crossbands on a lighter ground color, although sometimes the crossbands are staggered as half bands on either side of the body.[4]
The phylogeny of the three species has long been controversial. Studies based on morphological[3] and venom characteristics[7] support the idea that A. bilineatus and A. contortrix are more closely related. However, an analysis of mitochondrial DNA,[8] as well as more recent molecular studies,[9][10] have concluded that A. bilineatus and A. piscivorus are sister taxa, with A. contortrix being a sister species to them both.[4]
Geographic range
They are found in North America from the northeastern and central United States southward through peninsular Florida and southwestern Texas, and in Central America on the Atlantic versant from Tamaulipas and Nuevo León southward to the Yucatan Peninsula, Belize, and Guatemala. They are seen along the Pacific coastal plain and lower foothills from Sonora south through Guatemala, El Salvador, Honduras, and Nicaragua to northwestern Costa Rica.[1]
Behavior
All are semiaquatic to terrestrial and are often found near sources of water. However, A. contortrix and A. bilineatus are also found in dry habitats, often far from permanent streams or ponds.[4]
Reproduction
The members of this genus are all ovoviviparous.[4]
Venom
Pit vipers of the genus Agkistrodon rely on a potent venom they produce for their survival. Used to immobilize prey and fend off predators, one bite can inject enough venom into a human to cause severe pain, swelling, weakness, difficulty breathing, hemorrhaging, gangrene, fever, vomiting, and in rare instances, even death.[11]
The venom of all three species is assumed to be not unlike that of A. contortrix, which contains thrombin-like enzymes that act upon the coagulant activity of the blood. A study of electrophoretic patterns of proteins in venoms among and within populations of A. contortrix and A. piscivorus showed that substantial variation exists,[7] and no reason exists to believe that these differences do not correspond with variations in toxicity.[4]
Research
In a study conducted at the College of Medicine at the University of Florida, venom from A. piscivorous was injected into the lymph fluid of a frog. The frog immediately suffocated because of the collapse of its lung sacs. The venom even resulted in lung constriction when directly applied to the surface of the frog's lungs. To test this, trace amounts of venom were dropped onto a single pulmonary sac in a frog's lung after it was anesthetized and its chest cavity dissected open. A drop of solution containing a venom concentration of 1 mg/ml was enough to cause contraction of the pulmonary artery adventitia after 5-8 sec in a frog weighing 40 g.[12] The study found, however, that this toxic effect is simply a tool the snake can choose to employ from an accessory venom gland it has. In most instances, the viper injects a venom that tends to immobilize, not kill, its prey before ingestion. In this case, the main venom glands secrete a toxin that inhibits the prey’s sympathetic response to flee or fend off its predator. This essentially stuns the animal so that the predator can easily attack.[12]
Species
| Image | Species[2] | Taxon author[2] | Subsp.*[2] | Common name | Geographic range[1][13] |
|---|---|---|---|---|---|
|
A. bilineatus | (Günther, 1863) | 0 | cantil Mexican cantil |
Mexico and Central America. It is found from southern Sonora in Mexico south through Guatemala, El Salvador, and Honduras. |
|
A. contortrixT | (Linnaeus, 1766) | 5 | copperhead | The United States (Texas, Oklahoma, Kansas, Missouri, Arkansas, Louisiana, Mississippi, Alabama, Georgia, Florida, South Carolina, North Carolina, Tennessee, Kentucky, Virginia, West Virginia, Illinois, Indiana, Ohio, Iowa, Pennsylvania, Maryland, New Jersey, Delaware, New York, Connecticut, Massachusetts), Mexico (Chihuahua, Coahuila). |
| A. howardgloydi | Conant, 1984 | Gloyd's cantil Gloyd's moccasin |
Northwestern Costa Rica, western Nicaragua, southern Honduras. | ||
|
A. piscivorus | (Lacépède, 1789) | 3 | cottonmouth water moccasin |
The eastern United States from extreme southeastern Virginia, south through peninsular Florida and west to Arkansas, southeastern Kansas, eastern and southern Oklahoma and eastern and central Texas. A few records exist from along the Rio Grande in Texas, but these are thought to represent isolated populations that possibly no longer exist. |
| A. russeolus | Gloyd, 1972 | Yucatecan cantil | Mexico, northern Guatemala, northern Belize. | ||
|
A. taylori | Burger & Robertson, 1951 | Taylor's cantil ornate cantil |
Mexico. |
Not including the nominate subspecies. T Type species.[1]
Taxonomy
This genus was previously much larger and also included the following genera:[1]
- Calloselasma - Ground pit viper found in Southeast Asia (Malaya).
- Deinagkistrodon - The Hundred-pace viper found mostly in southern China.
- Gloydius - Ground pit vipers found in Asia.
- Hypnale - Hump-nosed vipers found in India and Sri Lanka.
See also
- List of crotaline species and subspecies
- Crotalinae by common name
- Crotalinae by taxonomic synonyms
- Snakebite
References
- ^ a b c d e f McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. 511 pp. ISBN 1-893777-00-6 (series). ISBN 1-893777-01-4 (volume).
- ^ a b c d "Agkistrodon". Integrated Taxonomic Information System. Retrieved 2 November 2006.
- ^ a b Gloyd HK, Conant R. 1990. Snakes of the Agkistrodon Complex: A Monographic Review. Society for the Study of Amphibians and Reptiles. 614 pp. 52 plates. LCCN 89-50342. ISBN 0-916984-20-6.
- ^ a b c d e f g Campbell JA, Lamar WW. 2004. The Venomous Reptiles of the Western Hemisphere. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. ISBN 0-8014-4141-2.
- ^ "Moccasin". The Word Detective. January 2014. Retrieved November 21, 2016.
- ^ Catherine C. Hopley (1882). Snakes: curiosities and wonders of serpent life. London, Griffith & Farran; New York, E.P. Dutton & co.
Besides that 'deadly moccasin' and frequent 'black snakes,' there were 'whip snakes,' 'milk snakes,' and many others which the negroes would bring home as trophies of their courageous slaughter; but by no scientific names were they known there. Except this name moccasin or mokesoji, which probably conveyed some especial meaning to the aborigines, few of the Indian vernaculars have been preserved in the United States, as we find them in other parts of America, which latter are treated of in chapters xxii. and xxiii. of this work ; but common English names prevail.
- ^ a b Jones JM (1976). "Variation of venom proteins in Agkistrodon snakes from North America". Copeia. 1976 (3): 558–562. doi:10.2307/1443375.
- ^ Knight A, Densmore III LD, Real ED (1992). "Molecular systematics of the Agkistrodon complex". pp. 49-70. In: Campbell JA, Brodie Jr ED (1992). Biology of the Pitvipers. Texas: Selva. 467 pp. 17 plates. ISBN 0-9630537-0-1
- ^ Parkinson CL (1999). "Molecular systematics and biogeographical history of pitvipers as determined by mitochondrial ribosomal DNA sequences". Copeia. 1999 (3): 576–586. doi:10.2307/1447591.
- ^ Parkinson CL, Moody SM, Ahlquist JE (1997). "Phylogenetic relationships of the "Agkistrodon complex" based on mitochondrial DNS data". pp. 63-78. In: Thorpe RS, Wüster W, Malhotra A (1997). Venomous Snakes: Ecology, Evolution, and Snakebite. Oxford: Clarendon Press
- ^ "Agkistrodon acutus pit vipers." Medical-Explorer.com; accessed April 2010. [1]
- ^ a b Gennaro JF, Hall HP, Casey ER, Hayes WK (September 2007). "Neurotropic effects of venoms and other factors that promote prey acquisition". Journal of Experimental Zoology. Part a, Ecological Genetics and Physiology. 307 (9): 488–99. doi:10.1002/jez.405. PMID 17620305.
- ^ Savage, JM. The Amphibians and Reptiles of Costa Rica. The University of Chicago Press, 2002, p. 719. ISBN 0-226-73537-0.
Further reading
- Daudin FM (1801-1803). Histoire naturelle, générale et particulière des reptiles: ouvrage faisant suit à l'histoire naturelle générale et particulière, composée par Leclerc de Buffon; et rédigée par C.S. Sonnini, miembre de plusieurs sociétés savantes. 8 vols. Paris: F. Dufart. (in French). [For a discussion of the publication date, see Harper F (1940). American Midland Nataturalist 23: 693].
- Fischer JG (1813). Zoognosia tabulis synopticus illustrata, in usum praelectionum Academiae Imperialis medico-chirurgicae Mosquensis edita. 3d ed. vol. 1, pt. 3 (Reptiles, Poissons): 57-117. Moscow: Nicolai Sergeidis Vsevolozsky. (in Latin).
- Fitzinger LJ (1826). Neue Classification der Reptilien nach ihren natürlichen Verwandtschaften: nebst einer Verwandtschafts-Tafel und einem Verzeichnisse der Reptilien-Sammlung des K. K. Zoologischen Museums zu Wien. Vienna: J.G. Heubner. five unnumbered + 67 pp. + one plate. (in German and Latin).
- Hubbs B, O'Connor B (2012). A Guide to the Rattlesnakes and other Venomous Serpents of the United States. Tempe, Arizona: Tricolor Books. 129 pp. ISBN 978-0-9754641-3-7.
- Link HF (1807). Beschreibung der naturalien-sammlung der Universität zu Rostock. Zweite abtheilung, pp. 51–100. Rostock: Gebruckt bei Adlers Erben. (in German).
- Palisot de Beauvois AMFJ (1799). "Memoir on Amphibia. Serpentes". Transactions of the American Philosophical Society. 4: 362–381. doi:10.2307/1005115.
- Sonnini CS, Latreille PA (1801). Histoire naturelle des reptiles, avec figures dissinees dápres nature. 4 Vols. Paris: Deterville. (in French). [For a discussion of the publication date, see Harper F (1940). American Midland Naturalist 23: 692-723].
- Troost G (1836). "On a new genus of serpents, and two new species of the genus Heterodon, inhabiting Tennessee". Ann. Lyc. Nat. Hist. 3. New York: 174–190.
- Wagler JG (1830). Natürliches System der Amphibien, mit vorangehender Classification der Säugthiere und Vögel. Ein Beitrag zur vergleichenden Zoologie. Munich, Stuttgart and Tübingen: J.G. Cotta. vi + 354 pp. + one plate. (in German and Latin).
External links
- Agkistrodon at the Reptarium.cz Reptile Database. Accessed 9 August 2007.