Atracotoxin may refer to:
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Atracidae is a family of mygalomorph spiders, commonly known as Australian funnel-web spiders or atracids. It has been included as a subfamily of the Hexathelidae, but is now recognized as a separate family. All members of the family are native to Australia. Atracidae consists of three genera: Atrax, Hadronyche, and Illawarra, comprising 35 species. Some members of the family produce venom that is dangerous to humans, and bites by spiders of six of the species have caused severe injuries to victims. The bite of the Sydney funnel-web spider and northern tree-dwelling funnel-web spider are potentially deadly, but no fatalities have occurred since the introduction of modern first-aid techniques and antivenom.
The redback spider, also known as the Australian black widow is a species of highly venomous spider believed to originate in the South Australian or adjacent Western Australian deserts, but now found throughout Australia, Southeast Asia and New Zealand, with colonies elsewhere outside Australia. It is a member of the cosmopolitan genus Latrodectus, the widow spiders. The adult female is easily recognised by her spherical black body with a prominent red stripe on the upper side of her abdomen and an hourglass-shaped red/orange streak on the underside. Females usually have a body length of about 10 millimetres (0.4 in), while the male is much smaller, being only 3–4 mm (0.12–0.16 in) long.
Hadronyche formidabilis, the northern tree-dwelling funnel-web spider, is a highly venomous mygalomorph spider found in Queensland and New South Wales. It is also known as the Northern Rivers funnel-web spider or northern funnel-web spider.
Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's plasma membrane. They belong to the superfamily of cation channels and can be classified according to the trigger that opens the channel for such ions, i.e. either a voltage-change ("Voltage-gated", "voltage-sensitive", or "voltage-dependent" sodium channel also called "VGSCs" or "Nav channel") or a binding of a substance (a ligand) to the channel (ligand-gated sodium channels).
Delta atracotoxin is a low-molecular-weight neurotoxic polypeptide found in the venom of the Sydney funnel-web spider.
Spider toxins are a family of proteins produced by spiders which function as neurotoxins. The mechanism of many spider toxins is through blockage of calcium channels.
omega-Atracotoxin (ω-atracotoxin) is an insect-specific neurotoxin produced by the Blue Mountains funnel-web spider. Its phylogenetic specificity derives from its ability to antagonise insect, but not vertebrate, voltage-gated calcium channels. Two spatially proximal amino acid residues, Asn(27) and Arg(35), form a contiguous molecular surface that is essential for toxin activity. It has been proposed that this surface of the beta-hairpin is a key site for interaction of the toxin with insect calcium channels.
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.