Venom optimization hypothesis

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Venom optimization hypothesis, also known as venom metering, is a biological hypothesis which postulates that venomous animals have physiological control over their production and use of venoms. It explains the economic use of venom because venom is a metabolically expensive product, and that there is a biological mechanism for controlling their specific use. The hypothetical concept was proposed by Esther Wigger, Lucia Kuhn-Nentwig, and Wolfgang Nentwig of the Zoological Institute at the University of Bern, Switzerland, in 2002. [1] [2]

Contents

A number of venomous animals have been experimentally found to regulate the amount of venom they use during predation or defensive situations. Species of anemones, jellyfish, ants, scorpions, spiders, and snakes are found to use their venoms frugally depending on the situation and size of their preys or predators. [3]

Development

Venom optimization hypothesis was postulated by Wigger, Kuhn-Nentwig, and Nentwig from their studies of the amount of venom used by a wandering spider Cupiennius salei . This spider produces a neurotoxic peptide called CsTx-1 for paralysing its prey. [4] It does not weave webs for trapping preys, and therefore, entirely depends on its venom for predation. It is known to prey on a variety of insects including butterflies, moths, earwigs, cockroaches, flies and grasshoppers. [5] Its venom glands store only about 10 μl of crude venom. Refilling of the glands takes 2–3 days and the lethal efficacy of the venom is, initially, very low for several days, requiring 8 to 18 days for full effect. [6] It was found that the amount of venom released differed for each specific prey. For example, for bigger and stronger insects like beetles, the spider uses the entire amount of its venom; while for small ones, it uses only a small amount, thus economizing its costly venom. [1] In fact, experiments show that the amount of venom released is just sufficient (at the lethal dose) to paralyze the target organism depending on the size or strength, and is not more than what is necessary. [7]

Concept

Animal venoms are complex biomolecules and hence, their biological synthesis require high metabolic activity. A particular venom itself is a complex chemical mixture composed of hundreds of proteins and non-proteinaceous compounds, resulting in a potent weapon for prey immobilization and predator deterrence. The metabolic cost of venom is sufficiently high to result in secondary loss of venom whenever its use becomes non-essential to survival of the animal. This suggests that venomous animals may have evolved strategies for minimizing venom expenditure, that they should use them only as and when required, and that too in optimal amount. [2]

Related Research Articles

A toxin is a harmful substance produced within living cells or organisms; synthetic toxicants created by artificial processes are thus excluded. The term was first used by organic chemist Ludwig Brieger (1849–1919), derived from the word toxic.

Venom Toxin secreted by an animal

Venom is a type of poison, especially one secreted by an animal. Venom has evolved in a wide variety of animals, both predators and prey, and both vertebrates and invertebrates.

<i>Phoneutria</i> Genus of spiders

Phoneutria is a genus of spiders in the family Ctenidae of potential medical significance to humans. They are mainly found in northern South America, with one species in Central America. Members of the genus are commonly referred to as Brazilian wandering spiders. Other English names include armed spiders and banana spiders.

Chinese red-headed centipede

The Chinese red-headed centipede, also known as the Chinese red head, is a centipede from East Asia and Australasia. It averages 20 cm (8 in) in length and lives in damp environments.

Venomous snake 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.

Spider bite Bite caused by a spider

A spider bite, also known as arachnidism, is an injury resulting from the bite of a spider. The effects of most bites are not serious. Most bites result in mild symptoms around the area of the bite. Rarely they may produce a necrotic skin wound or severe pain.

<i>Phoneutria nigriventer</i> Species of arachnid

Phoneutria nigriventer is a species of medically significant spider in the family Ctenidae, found in South America. Along with other members of the genus, they are often referred to as Brazilian wandering spiders.

Venomous fish Fish that have the ability to produce toxins

Venomous fish are species of fish which produce strong mixtures of toxins harmful to humans which they deliberately deliver by means of a bite, sting, or stab, resulting in an envenomation. As a contrast, poisonous fish also produce a strong toxin, but they do not bite, sting, or stab to deliver the toxin, instead being poisonous to eat because the human digestive system does not destroy the toxin they contain in their bodies. Venomous fish do not necessarily cause poisoning if they are eaten, as the digestive system often destroys the venom.

<i>Ancylometes</i> Genus of spiders

Ancylometes is a genus of Central and South American semiaquatic wandering spiders first described by Philipp Bertkau in 1880. Originally placed with the nursery web spiders, it was moved to the Ctenidae in 1967. The genus name is derived in part from Ancient Greek "ἀγκύλος", meaning "crooked, bent".

Caudal luring Form of aggressive mimicry where the predator attracts prey using its tail

Caudal luring is a form of aggressive mimicry in which a predator uses tail movements to attract prey. The prey animal misinterprets the tail as a worm-like species or another smaller prey. Once the prey animal is within striking range, the predator attacks. Snakes, often juveniles, and some types of shark are the main species that practice caudal luring.

<i>Cupiennius</i> Genus of spiders

Cupiennius, known by the common name banana spiders, is a genus of araneomorph spiders in the family Trechaleidae, named by Eugène Simon in 1891. They are found from Mexico to northwestern South America, and on some Caribbean islands. Unlike the dangerously venomous Phoneutria, bites from these spiders typically have only minor effects on humans, and have been compared to a bee sting.

Pseudomyrmex triplarinus is a venomous species of ant that lives in symbiosis with trees of the genus Triplaris, including the South American species T. americana, T. cumingiama, and T. felipensis. The ant protects the trees against predation by other insects and animals. The ant's venom has anti-inflammatory properties.

<i>Cupiennius salei</i> Species of spider

Cupiennius salei, commonly called the tiger wandering spider, is a large spider belonging to a group of wandering spiders found in Central America, although this species is specifically from Eastern Mexico, Guatemala, Belize and Honduras. The species was accidentally introduced into Germany in the early 20th century from banana plantations in Central America. In the mid-1950s it was realised that the spider is an ideal model for biological research because of its large size, inactive behaviour, and ease of breeding in laboratories. From an initial 1963 publication on its biological characteristics, it has become the most studied species of spider. Furthermore, the spider is now known to produce a complex neurotoxic venom, such as cupiennins and CSTX, of which a peptide called CsTx-1 is highly potent for paralysing its prey. Its toxin has also become one of the most studied among those of venomous spiders. As the spider does not produce a web for trapping prey, being venomous is its primary strategy for prey capture. It is known to prey on a wide range of insects and small vertebrates.

CSTX is a name given to a group of closely related neurotoxic peptides present in the venom of the wandering spider Cupiennius salei. There are twenty types so far described for this protein group. However, some are reclassified into cupiennins group of toxin, including CSTX-3, -4, -5, and -6, because of their chemical affinity. The first thirteen were isolated and identified in 1994 by Lucia Kuhn-Nentwig, Johann Schaller, and Wolfgang Nentwig of the Zoological Institute at the University of Bern, Switzerland. The different types are most likely the products of splicing variant of the same gene. They are all L-type calcium channel blockers, and also exhibit cytolytic activity by forming an alpha-helix across the cell membrane in mammalian neurons. They also inhibit voltage-gated calcium channels in insect neurons.

Cupiennins are a group of small cytolytic peptides from the venom of the wandering spider Cupiennius salei. They are known to have high bactericidal, insecticidal and haemolytic activities. They are chemically cationic α-helical peptides. They were isolated and identified in 2002 as a family of peptides called cupiennin 1. The sequence was determined by a process called Edman degradation, and the family consists of cupiennin 1a, cupiennin 1b, cupiennin 1c, and cupiennin 1d. The amino acid sequences of cupiennin 1b, c, and d were obtained by a combination of sequence analysis and mass spectrometric measurements of comparative tryptic peptide mapping. Even though they are not strong toxins, they do enhance the effect of the spider venom by synergistically enhancing other components of the venom, such CSTX.

Plectreurys tristis is a species of venomous spiders commonly known as primitive hunting spiders belonging to a family of plectreurid spiders. They produce a venom that contains a group of insecticidal peptides called plectoxins. They are found in western North America, Central America and Mexico.

Evolution of snake venom The origin and diversification of snake venom through geologic time

Venom in snakes and some lizards is a form of saliva that has been modified into venom over its evolutionary history. In snakes, venom has evolved to kill or subdue prey, as well as to perform other diet-related functions. The evolution of venom is thought to be responsible for the enormous expansion of snakes across the globe.

The pathophysiology of a spider bite is due to the effect of its venom. A spider envenomation occurs whenever a spider injects venom into the skin. Not all spider bites inject venom – a dry bite, and the amount of venom injected can vary based on the type of spider and the circumstances of the encounter. The mechanical injury from a spider bite is not a serious concern for humans. Some spider bites do leave a large enough wound that infection may be a concern. However, it is generally the toxicity of spider venom that poses the most risk to human beings; several spiders are known to have venom that can cause injury to humans in the amounts that a spider will typically inject when biting.

Loxosceles adelaida is a species of venomous recluse spider found in South America.

Venomics is the large-scale study of proteins associated with Venom. Venom is a toxic substance secreted by animals, which is typically injected either offensively or defensively into prey or aggressors, respectively.

References

  1. 1 2 Wigger E, Kuhn-Nentwig L, Nentwig W (2002). "The venom optimisation hypothesis: a spider injects large venom quantities only into difficult prey types". Toxicon. 40 (6): 749–752. doi:10.1016/S0041-0101(01)00277-X. PMID   12175611.
  2. 1 2 Morgenstern D, King GF (2013). "The venom optimization hypothesis revisited". Toxicon. 63: 120–128. doi:10.1016/j.toxicon.2012.11.022. PMID   23266311.
  3. ↑ Nisani Z (2008). Behavioral and Physiological Ecology of Scorpion Venom Expenditure: Stinging, Spraying, and Venom Regeneration. pp. 32–39. ISBN   9780549591610.
  4. ↑ Kuhn-Nentwig L, Fedorova IM, Lüscher BP, Kopp LS, Trachsel C, Schaller J, Vu XL, Seebeck T, Streitberger K, Nentwig W, Sigel E, Magazanik LG (2012). "A venom-derived neurotoxin, CsTx-1, from the spider Cupiennius salei exhibits cytolytic activities". J Biol Chem. 287 (30): 25640–25649. doi: 10.1074/jbc.M112.339051 . PMC   3408166 . PMID   22613721.
  5. ↑ Nentwig W (1986). "Non-webbuilding spiders: prey specialists or generalists?". Oecologia. 69 (4): 571–576. Bibcode:1986Oecol..69..571N. doi:10.1007/BF00410365. PMID   28311618. S2CID   5871434.
  6. ↑ Boevé JL, Kuhn-Nentwig L, Keller S, Nentwig W (1995). "Quantity and quality of venom released by a spider (Cupiennius salei, Ctenidae)". Toxicon. 33 (10): 1347–1357. doi:10.1016/0041-0101(95)00066-U. PMID   8599185.
  7. ↑ Kuhn-Nentwig L, Schaller J, Nentwig W (2004). "Biochemistry, toxicology and ecology of the venom of the spider Cupiennius salei (Ctenidae)". Toxicon. 43 (5): 543–553. doi:10.1016/j.toxicon.2004.02.009. PMID   15066412.
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