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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.
Defensins are small cysteine-rich cationic proteins across cellular life, including vertebrate and invertebrate animals, plants, and fungi. They are host defense peptides, with members displaying either direct antimicrobial activity, immune signalling activities, or both. They are variously active against bacteria, fungi and many enveloped and nonenveloped viruses. They are typically 18-45 amino acids in length, with three or four highly conserved disulphide bonds.
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.
A latrotoxin is a high-molecular mass neurotoxin found in the venom of spiders of the genus Latrodectus and also found in the venom of spider species, Steatoda nobilis. Latrotoxins are the main active components of the venom and are responsible for the symptoms of latrodectism.
In pharmacology, the term mechanism of action (MOA) refers to the specific biochemical interaction through which a drug substance produces its pharmacological effect. A mechanism of action usually includes mention of the specific molecular targets to which the drug binds, such as an enzyme or receptor. Receptor sites have specific affinities for drugs based on the chemical structure of the drug, as well as the specific action that occurs there.
Tx2-6 is a toxin found in the venom of the Brazilian wandering spider, Phoneutria nigriventer(Keyserling). It is a peptide of 48 residues, molecular weight 5291.3. This peptide is cleaved from a longer precursor with a signal peptide and a glutamine-rich propeptide. It can cause priapism. Tests on rats indicate that the toxin causes nitric oxide release, and its effect on erection is blocked by the nitric oxide synthase inhibitor L-NAME. However, it fully restored erectile function in rats developing hypertension due to injection of deoxycorticosterone acetate. A study is underway at the Medical College of Georgia looking at possible uses for the chemical in erectile dysfunction medication. Scientists and Gregory Ochs are collaborating on this study.
Agatoxins are a class of chemically diverse polyamine and peptide toxins which are isolated from the venom of various spiders. Their mechanism of action includes blockade of glutamate-gated ion channels, voltage-gated sodium channels, or voltage-dependent calcium channels. Agatoxin is named after the funnel web spider which produces a venom containing several agatoxins. There are different agatoxins. The ω-agatoxins are approximately 100 amino acids in length and are antagonists of voltage-sensitive calcium channels and also block the release of neurotransmitters. For instance, the ω-agatoxin 1A is a selective blocker and will block L-type calcium channels whereas the ω-agatoxin 4B will inhibit voltage sensitive P-type calcium channels. The μ-agatoxins only act on insect voltage-gated sodium channels.
Scolopendra polymorpha, the common desert centipede, tiger centipede, banded desert centipede, or Sonoran Desert centipede, is indigenous to the Southwestern United States and northern Mexico, north to the Pacific coast. It inhabits dry grasslands, forest, and desert; in these habitats, the centipedes generally take up residence under rocks, though they have been observed creating burrows in suitable environments and inside rotting logs.
Stromatoxin is a spider toxin that blocks certain delayed-rectifier and A-type voltage-gated potassium channels.
Mesobuthus eupeus is a polymorphic scorpion species belonging to the well-known family Buthidae. Commonly known as the lesser Asian scorpion or the mottled scorpion. It is thought to be the most widely dispersed species of the genus Mesobuthus, perhaps even of the family Buthidae.
delta-Palutoxins (δ-palutoxins) consist of a homologous group of four insect-specific toxins from the venom of the spider Pireneitega luctuosa. They show a high toxicity against Spodoptera litura larvae by inhibiting sodium channels, leading to strong paralytic activity and eventually to the death of the insect.
Covalitoxin-II is a peptide toxin that is produced by the spider Coremiocnemis validus. It can induce excitatory, non-lethal behavioral symptoms like quivering and jerking in crickets.
Cupiennius salei, commonly called the tiger bromeliad spider, are large bodied, actively-hunting spiders that are part of the family Trechaleidae. They are found in Central America and Mexico, while other species in the genus are also found in various parts of South America. They are visually similar to another group called wandering spiders. More precisely, this species naturally occurs in Eastern Mexico, Guatemala, Belize, Honduras, Nicaragua and possibly into northwestern Costa Rica. Yet, it has also been introduced to various parts of the world either by accidental imports, or deliberately introduced elsewhere as either a laboratory model organism an exotic pet. However, it has not yet been recorded as established in the wild outside of its native Mexico and Central America.
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.
Oxyopinins are a group of peptide toxins present in the venom of lynx spiders belonging to the genus Oxyopes, from which they derive their name.
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.
Oxyopes takobius is a species of spiders in the genus Oxyopes of the lynx spider family, Oxyopidae. The species was first described in 1969, and is found from Central Asia to China. Its venom contains a peptide toxin called oxyopinin, which was discovered in 2002.
Avicularia rufa is a species of spider in the family Theraphosidae. Specimens from the Brazilian states of Mato Grosso and Rondônia have regularly been misidentified as Avicularia juruensis. One difference is the vivid yellow rings on the legs of A. rufa compared to the paler rings of A. juruensis.
Spooky toxin (SsTx) is a small peptide neurotoxin. It is found in the venom of Chinese red-headed centipedes, also known as golden head centipedes. It is originally composed of 76 amino acids, with a molecular weight of 6017.5 Daltons, but loses the first 23 residues and becomes 53 residues long. SsTx is currently thought to be unique to Scolopendra subspinipes mutilans.
Delta hexatoxin Hv1 is a neurotoxic component found in the venom of the Australian funnel web spider.
References
- ↑ Kozlov SA, Vassilevski AA, Feofanov AV, Surovoy AY, Karpunin DV, Grishin EV (July 2006). "Latarcins, antimicrobial and cytolytic peptides from the venom of the spider Lachesana tarabaevi (Zodariidae) that exemplify biomolecular diversity". J. Biol. Chem. 281 (30): 20983–92. doi: 10.1074/jbc.M602168200 . PMID 16735513.
- ↑ Dubovskii, P.V.; Vassilevski, A.A.; Kozlov, S.A.; Feofanov, A.V.; Grishin, E.V.; Efremov, R.G. (2015). "Latarcins: versatile spider venom peptides". Cellular and Molecular Life Sciences. 72 (23): 4501–4522. doi:10.1007/s00018-015-2016-x. PMID 26286896. S2CID 14177431.