Toxungen

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Experimentally induced toxungen spraying by the scorpion Parabuthus transvaalicus. Toxungen sqraying by the scorpion Parabuthus transvaalicus.jpg
Experimentally induced toxungen spraying by the scorpion Parabuthus transvaalicus.

Toxungen comprises a secretion or other body fluid of one or more biological toxins that is transferred by one animal to the external surface of another animal via a physical delivery mechanism. [1] Toxungens can be delivered through spitting, spraying, or smearing. As one of three categories of biological toxins, toxungens can be distinguished from poisons, which are passively transferred via ingestion, inhalation, or absorption across the skin, and venoms, which are delivered through a wound generated by a bite, sting, or other such action. [2] Toxungen use offers the evolutionary advantage of delivering toxins into the target's tissues without the need for physical contact. [3]

Contents

Taxonomic distribution

Toxungens have evolved in a variety of animals, including flatworms, [4] insects, [5] [6] arachnids, [7] cephalopods, [8] amphibians, [9] and reptiles. [10]

Toxungen use possibly exists in birds, as a number of species deploy defensive secretions from their stomachs, uropygial glands, or cloacas, and some anoint themselves with heterogenously acquired chemicals from millipedes, caterpillars, beetles, plant materials, and even manufactured pesticides. [11] [12] Some of the described substances may be toxic, at least to ectoparasites, which would qualify them as toxungens.

Toxungen use might also exist in several mammal groups. Slow lorises (genus Nycticebus), which comprise several species of nocturnal primates in Southeast Asia, produce a secretion in their brachial glands (a scent gland near their armpit) that possesses apparent toxicity. [13] [14] [15] When the secretion is licked and combined with saliva, their bite introduces the secretion into a wound, which can cause sometimes severe tissue injury to conspecifics and other aggressors, thereby functioning as a venom. They can also rub the secretion on their fur or lick their offspring before stashing them in a secure location, thereby functioning potentially as a toxungen. Skunks and several other members of Mephitidae and Mustelidae spray a noxious and potentially injurious secretion from their anal sac when threatened. [16] High concentrations of the spray can be toxic, [17] with rare accounts of spray victims suffering injury and even death. [18] [19]

Although the extinct theropod Dilophosaurus was portrayed in the original Jurassic Park and Jurassic World Dominion movies as capable of spitting a toxic secretion, no evidence exists to suggest that any dinosaur possessed either a toxungen or venom. [20]

Classification of toxin deployment

Animals that deploy toxungens are referred to as toxungenous. Some animals use their toxins in multiple ways, and can be classified as poisonous, toxungenous, and/or venomous. Examples include the scorpion Parabuthus transvaalicus , which is both toxungenous (can spray its toxins) and venomous (can inject its toxins), [21] [22] and the snake Rhabdophis tigrinus , which is poisonous (sequesters toad and/or firefly toxins in its nuchal gland tissues that are toxic if consumed by a predator), toxungenous (the nuchal glands are pressurized and can spray the toxins when ruptured), and venomous (toxic oral gland secretions can be injected via the teeth). [23] Even humans can be considered facultatively poisonous, toxungenous, and venomous because they sometimes make use of toxins by all three means for research and development (e.g., biomedical purposes), agriculture (e.g., spraying insecticides), and nefarious reasons (to kill other animals, including humans). [24]

Evolution and function

Toxungen deployment offers a key evolutionary advantage compared to poisons and venoms. Poisons and venoms require direct contact with the target animal, which puts the toxin-possessing animal at risk of injury and death from a potentially dangerous enemy. Evolving the capacity to spit or spray a toxic secretion can reduce this risk by delivering the toxins from a distance. [25]

Toxins used as toxungens can be acquired by several means. Many species synthesize their own toxins and store them within glands, but others acquire their toxins exogenously from other species. Two examples illustrate exogenous acquisition. Snakes of the genus Rhabdophis sequester their nuchal gland toxins from their diet of toads and/or fireflies, [26] [27] Blue-ringed octopuses (genus Hapalochlaeana ) acquire tetrodotoxin, the highly toxic non-proteinaceous component of their salivary glands that can be ejected into the water to subdue nearby prey, via accumulation from food resources and/or symbiotic tetrodotoxin-producing bacteria. [28] [29]

Toxungens are most commonly used for defensive purposes, but can be used in other contexts as well. Examples of toxungen use for predation include the blue-ringed octopus, which can squirt its secretion into water to immobilize or kill its prey, [30] and ants of the genus Crematogaster that cooperatively subdue their prey by seizing, spread-eagling, and then smearing their toxins onto the prey's surface. [31] Toxungens can also be used for communication and hygiene. Many hymenopterans possess a secretion used as a venom (injected for predation and/or defense) that can also be sprayed to communicate alarm among nestmates, to mark a trail used for food gathering, or to keep their brood free of parasites. [32]

Because of their unique delivery system, toxungens may be chemically designed to better penetrate body surfaces. Arthropods that spray or smear their secretion onto insect prey enhance toxin penetration by including a spreading agent that additionally enhances toxicity. [33] [34] [35] Some Spitting cobras have modified their secretion so that the cardiotoxins are more injurious to eye membranes. [36]

Related Research Articles

<span class="mw-page-title-main">Toxin</span> Naturally occurring organic poison

A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. They occur especially as proteins, often conjugated. The term was first used by organic chemist Ludwig Brieger (1849–1919) and is derived from the word "toxic".

<span class="mw-page-title-main">Venom</span> Toxin secreted by an animal

Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved venom apparatus, such as fangs or a stinger, in a process called envenomation. Venom is often distinguished from poison, which is a toxin that is passively delivered by being ingested, inhaled, or absorbed through the skin, and toxungen, which is actively transferred to the external surface of another animal via a physical delivery mechanism.

<span class="mw-page-title-main">Batrachotoxin</span> Chemical compound

Batrachotoxin (BTX) is an extremely potent cardio- and neurotoxic steroidal alkaloid found in certain species of beetles, birds, and frogs. The name is from the Greek word βάτspan>bátrachos, 'frog'. Structurally-related chemical compounds are often referred to collectively as batrachotoxins. In certain frogs, this alkaloid is present mostly on the skin. Such frogs are among those used for poisoning darts. Batrachotoxin binds to and irreversibly opens the sodium channels of nerve cells and prevents them from closing, resulting in paralysis and death. No antidote is known.

Bufagin is a toxic steroid C24H34O5 obtained from toad's milk, the poisonous secretion of a skin gland on the back of the neck of a large toad (Rhinella marina, synonym Bufo marinus, the cane toad). The toad produces this secretion when it is injured, scared or provoked. Bufagin resembles chemical substances from digitalis in physiological activity and chemical structure.

<span class="mw-page-title-main">Colorado River toad</span> Species of amphibian

The Colorado River toad, also known as the Sonoran Desert toad, is a toad species found in northwestern Mexico and the southwestern United States. It is well known for its ability to exude toxins from glands within its skin that have psychoactive properties.

<span class="mw-page-title-main">Spitting cobra</span> Common name for several snakes

A ”spitting” cobra is any of several species of cobra that can intentionally, defensively shoot their venom directly from their fangs. This substance has two functions, with the first being as venom that can be absorbed via the victim’s eyes, mouth, or nose, and secondly as a toxungen, which can be sprayed on the target surface. Their ability to target and shoot venom is utilised in several different ways, self-defense being the most common instance. Studies have shown that the targets are far from random; rather, spitting cobras consciously take aim, directing their spray as close as possible to the eyes and face of an aggressor.

<span class="mw-page-title-main">Samandarin</span> Chemical compound (steroidal alkaloid)

Samandarin or Samandarine is the main steroidal alkaloid secreted by the fire salamander (Salamandra salamandra). The compound is extremely toxic (LD50 = 70 µg/kg in mice). Poisoning can cause convulsions, respiratory paralysis, and eventual death. Samandarin is also believed to be the active ingredient in Salamander brandy, a Slovenian drink with purported hallucinogenic and aphrodisiac effects.

<span class="mw-page-title-main">Venomous mammal</span> Venom-producing animals of the class Mammalia

Venomous mammals are animals of the class Mammalia that produce venom, which they use to kill or disable prey, to defend themselves from predators or conspecifics or in agonistic encounters. Mammalian venoms form a heterogeneous group with different compositions and modes of action, from three orders of mammals: Eulipotyphla, Monotremata, and Chiroptera. It has been proposed that some members of a fourth order, Primates, are venomous. To explain the rarity of venom delivery in Mammalia, Mark Dufton of the University of Strathclyde has suggested that modern mammalian predators do not need venom because they are able to kill quickly with their teeth or claws, whereas venom, no matter how sophisticated, requires time to disable prey.

<span class="mw-page-title-main">Toxicofera</span> Proposed clade of scaled reptiles

Toxicofera is a proposed clade of scaled reptiles (squamates) that includes the Serpentes (snakes), Anguimorpha and Iguania. Toxicofera contains about 4,600 species, of extant Squamata. It encompasses all venomous reptile species, as well as numerous related non-venomous species. There is little morphological evidence to support this grouping; however, it has been recovered by all molecular analyses as of 2012.

A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus Latrodectus as well as at least one species of another genus in the same family, Steatoda nobilis. Latrotoxins are the main active components of the venom and are responsible for the symptoms of latrodectism.

<i>Rhabdophis subminiatus</i> Species of snake

Rhabdophis subminiatus, commonly called the red-necked keelback or red-necked keelback snake, is a species of venomous snake in the subfamily Natricinae of the family Colubridae. The species is endemic to Asia.

<span class="mw-page-title-main">Venomous snake</span> Species of the suborder Serpentes that produce venom

Venomous snakes are species of the suborder Serpentes that are capable of producing venom, which they use for killing prey, for defense, and to assist with digestion of their prey. The venom is typically delivered by injection using hollow or grooved fangs, although some venomous snakes lack well-developed fangs. Common venomous snakes include the families Elapidae, Viperidae, Atractaspididae, and some of the Colubridae. The toxicity of venom is mainly indicated by murine LD50, while multiple factors are considered to judge the potential danger to humans. Other important factors for risk assessment include the likelihood that a snake will bite, the quantity of venom delivered with the bite, the efficiency of the delivery mechanism, and the location of a bite on the body of the victim. Snake venom may have both neurotoxic and hemotoxic properties. There are about 600 venomous snake species in the world.

<i>Parabuthus transvaalicus</i> Species of scorpion

Parabuthus transvaalicus is a species of venomous scorpion from semi-arid parts of southern Africa.

Tityustoxin is a toxin found in the venom of scorpions from the subfamily Tityinae. By binding to voltage-dependent sodium ion channels and potassium channels, they cause sialorrhea, lacrimation and rhinorrhea.

<span class="mw-page-title-main">Duvernoy's gland</span> Gland found in some groups of colubrid snakes

The Duvernoy's gland is a gland found in some groups of colubrid snakes. It is distinguished from the venom gland and is not found in viperids or elapids. It was named for French zoologist Georges Louis Duvernoy who first described the gland in 1832.

Birtoxin is a neurotoxin from the venom of the South African Spitting scorpion. By changing sodium channel activation, the toxin promotes spontaneous and repetitive firing much like pyrethroid insecticides do

Bestoxin is a neurotoxin from the venom of the South African spitting scorpion Parabuthus transvaalicus. Most likely, it targets sodium channel function, thus promoting spontaneous and repetitive neuronal firing. Following injection into mice, it causes non-lethal writhing behaviour.

Altitoxin is a neurotoxin found in the South African scorpion Parabuthus transvaalicus. Injection of altitoxin in mice leads to akinesia, depression and death.

Ikitoxin is a neurotoxin from the venom of the South African Spitting scorpion that targets voltage-sensitive sodium channels. It causes unprovoked jumps in mice following intracerebroventricular injections.

Polymorphic toxins (PTs) are multi-domain proteins primarily involved in competition between bacteria but also involved in pathogenesis when injected in eukaryotic cells. They are found in all major bacterial clades.

References

  1. ↑ Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi:10.1111/brv.12062. PMID: 24102715.
  2. ↑ Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi:10.1111/brv.12062. PMID: 24102715.
  3. ↑ Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi:10.1111/brv.12062. PMID: 24102715.
  4. ↑ Koopowitz, H. (1970). "Feeding behaviour and the role of the brain in the polyclad flatworm, Planocera gilchristi". Animal Behavior 18, 31–35. doi:10.1016/0003-3472(70)90066-7.
  5. ↑ Deml, R. & Dettner, K. (1994). Attacus atlas caterpillars (Lep., Saturniidae) spray an irritant secretion from defensive glands. Journal of Chemical Ecology 20, 2127–2138. doi:10.1007/BF02066249. PMID: 24242735.
  6. ↑ Eisner, T., Aneshansley, D. J., Eisner, M., Attygalle, A. B., Alsop, D. W. & Meinwald, J. (2000a). "Spray mechanism of the most primitive bombardier beetle (Metrius contractus)". Journal of Experimental Biology 203, 1265–1275. doi:10.1242/jeb.203.8.1265. PMID: 10729276.
  7. ↑ Nisani, Z., & Hayes, W. K. (2015). "Venom-spraying behavior of the scorpion Parabuthus transvaalicus (Arachnida: Buthidae)". Behavioural Processes, 115, 46-52. doi:10.1016/j.beproc.2015.03.002. PMID: 25748565.
  8. ↑ Sutherland, S. & Lane, W. (1969). "Toxins and mode of envenomation of the common ringed or blue-banded octopus". Medical Journal of Australia 1, 893–898. doi:10.5694/j.1326-5377.1969.tb49778.x. PMID: 4977737.
  9. ↑ Brodie, E. D. & Smatresk,N. J. (1990). "The antipredator arsenal of fire salamanders: spraying of secretions from highly pressurized dorsal skin glands". Herpetologica 46, 1–7. https://www.jstor.org/stable/3892595.
  10. ↑ Berthé, R. A., De Pury, S., Bleckmann, H., & Westhoff, G. (2009). "Spitting cobras adjust their venom distribution to target distance". Journal of Comparative Physiology A, 195(8), 753-757. doi : 10.1007/s00359-009-0451-6. PMID   19462171.
  11. ↑ J.P. Dumbacher and Pruett-Jones, S. (1996). "Avian chemical defense". In: Nolan, V., Jr., and Ketterson, E. D. (Eds.), Current Ornithology, vol. 13, Plenum Press, New York (1996), pp. 137-174. doi : 10.1007/978-1-4615-5881-1_4
  12. ↑ Morozov, N. S. (2015). Why do birds practice anting? Biology Bulletin Reviews, 5(4), 353-365. doi : 10.1134/S2079086415040076
  13. ↑ Alterman, L. (1995). "Toxins and toothcombs: potential allospecific chemical defenses in Nycticebus and Perodicticus". In Alterman, L.; Doyle, G.A.; Izard, M.K (eds.). Creatures of the Dark: The Nocturnal Prosimians. New York, New York: Plenum Press. Pp. 413–424. ISBN   978-0-306-45183-6. OCLC   33441731.
  14. ↑ Nekaris, K., Moore, R. S., Rode, E. J., & Fry, B. G. (2013). Mad, bad and dangerous to know: the biochemistry, ecology and evolution of slow loris venom. Journal of Venomous Animals and Toxins including Tropical Diseases, 19, 1-10. doi : 10.1186/1678-9199-19-21. PMID   31074351.
  15. ↑ Nekaris, K. A. I., Campera, M., Nijman, V., Birot, H., Rode-Margono, E. J., Fry, B. G., ... & Imron, M. A. (2020). Slow lorises use venom as a weapon in intraspecific competition. Current Biology, 30(20), R1252-R1253. doi : 10.1016/j.cub.2020.08.084. PMID   33080192.
  16. ↑ Stankowich, T., Caro, T., & Cox, M. (2011). Bold coloration and the evolution of aposematism in terrestrial carnivores. Evolution, 65(11), 3090-3099. doi : 10.1111/j.1558-5646.2011.01334.x. PMID   22023577.
  17. ↑ Wood, W. F. (1999). The history of skunk defensive secretion research. The Chemical Educator, 4(2), 44-50. doi : 10.1007/s00897990286a.
  18. ↑ Zaks, K. L., Tan, E. O., & Thrall, M. A. (2005). Heinz body anemia in a dog that had been sprayed with skunk musk. Journal of the American Veterinary Medical Association, 226(9), 1516-1518. doi : 10.2460/javma.2005.226.1516. PMID   15882003.
  19. ↑ Fierro, B. R., Agnew, D. W., Duncan, A. E., Lehner, A. F., & Scott, M. A. (2013). Skunk musk causes methemoglobin and Heinz body formation in vitro. Veterinary Clinical Pathology, 42(3), 291-300. doi : 10.1111/vcp.12074. PMID   24033800.
  20. ↑ Carter, N. Undated. "The real Dilophosaurus." At Blogosaur, Phillip J. Curie Dinosaur Museum.
  21. ↑ Nisani, Z., & Hayes, W. K. (2015). "Venom-spraying behavior of the scorpion Parabuthus transvaalicus (Arachnida: Buthidae)". Behavioural Processes, 115, 46-52. doi:10.1016/j.beproc.2015.03.002. PMID: 25748565.
  22. ↑ Nisani, Z., & Hayes, W. K. (2011). "Defensive stinging by Parabuthus transvaalicus scorpions: risk assessment and venom metering". Animal Behaviour, 81(3), 627-633. doi:10.1016/j.anbehav.2010.12.010.
  23. ↑ Mori, A., Burghardt, G. M., Savitzky, A. H., Roberts, K. A., Hutchinson, D. A., & Goris, R. C. (2012). "Nuchal glands: a novel defensive system in snakes". Chemoecology, 22(3), 187-198. doi:10.1007/s00049-011-0086-2.
  24. ↑ Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi: 10.1111/brv.12062. PMID: 24102715.
  25. ↑ Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi:10.1111/brv.12062. PMID: 24102715.
  26. ↑ Hutchinson, D. A., Mori, A., Savitzky, A. H., Burghardt, G. M., Wu, X., Meinwald, J., & Schroeder, F. C. (2007). "Dietary sequestration of defensive steroids in nuchal glands of the Asian snake Rhabdophis tigrinus". Proceedings of the National Academy of Sciences, 104(7), 2265-2270. doi:10.1073/pnas.0610785104. PMID: 17284596.
  27. ↑ Fukuda, M., & Mori, A. (2021). "Does an Asian natricine snake, Rhabdophis tigrinus, have chemical preference for a skin toxin of toads?" Current Herpetology, 40(1), 1-9. doi: [ doi : 10.5358/hsj.40.1 10.5358/hsj.40.1].
  28. ↑ Sutherland, S. & Lane, W. (1969). "Toxins and mode of envenomation of the common ringed or blue-banded octopus". Medical Journal of Australia 1, 893–898. doi:10.5694/j.1326-5377.1969.tb49778.x. PMID: 4977737.
  29. ↑ Yamate, Y., Takatani, T., & Takegaki, T. (2021). "Levels and distribution of tetrodotoxin in the blue-lined octopus Hapalochlaena fasciata in Japan, with special reference to within-body allocation." Journal of Molluscan Studies, 87(1), eyaa042. doi: .
  30. ↑ Sutherland, S. & Lane, W. (1969). "Toxins and mode of envenomation of the common ringed or blue-banded octopus". Medical Journal of Australia 1, 893–898. doi:10.5694/j.1326-5377.1969.tb49778.x. PMID: 4977737.
  31. ↑ Richard, F. J., Fabre, A. & Dejean, A. (2001). "Predatory behavior in dominant arboreal ant species: the case of Crematogaster sp. (Hymenoptera: Formicidae)". Journal of Insect Behavior 14, 271–282. doi:10.1023/A:1007845929801.
  32. ↑ Nelsen, D. R., Nisani, Z., Cooper, A. M., Fox, G. A., Gren, E. C., Corbit, A. G., & Hayes, W. K. (2014). "Poisons, toxungens, and venoms: redefining and classifying toxic biological secretions and the organisms that employ them". Biological Reviews, 89(2), 450-465. doi:10.1111/brv.12062. PMID: 24102715.
  33. ↑ Eisner, T., Meinwald, J., Monro, A. & Ghent, R. (1961). "Defence mechanisms of Arthropods. I. The composition and function of the spray of the whipscorpion, Mastigoproctus giganteus (Lucas)(Arachnida, Pedipalpida)". Journal of Insect Physiology 6, 272–298. doi:10.1016/0022-1910(61)90054-3.
  34. ↑ Prestwich, G. D. (1984). "Defense-mechanisms of termites". Annual Review of Entomology 29, 201–232. doi:10.1146/annurev.en.29.010184.001221.
  35. ↑ Eisner, T., Rossini, C. & Eisner, M. (2000b). "Chemical defense of an earwig (Doru taeniatum)". Chemoecology 10, 81–87. doi:10.1007/s000490050011.
  36. ↑ Ismail,M., Al-Bekairi, A.M., El-Bedaiwy, A.M. & Abd-El Salam,M. A. (1993). "The ocular effect of spitting cobras: II. Evidence that cardiotoxins are responsible for the corneal opacification syndrome". Clinical Toxicology 31, 45–62. doi:10.3109/15563659309000373. PMID: 8433415.
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