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Native toxins from stinging trees coincide with the pain of spiders and scorpions



Native toxins from stinging trees coincide with the pain of spiders and scorpions

The spicy Gympie Gympie tree has needle-shaped trichomes that inject toxins. Credit: Institute for Molecular Bioscience, University of Queensland

Researchers at the University of Queensland have found that the painful toxins sent by a giant Australian tree are strikingly similar to the poison found in spiders and cone snails.

The spicy Gympie-Gympie tree is one of the most poisonous plants in the world and causes extreme long-lasting pain.

Associate Professor Irina Vetter, Dr. Thomas Durek and her teams at the UQ̵

7;s Institute of Molecular Bioscience found a new family of toxins, which they named “gympietides” after the spicy tree Gympie -Gympie.

The scientific name of the tree is Dendrocnide, which literally means “spicy tree”, a member of the nettle family that can be found in Australia from the Northern Rivers region of NSW, through Gympie QLD and to the tip of the Cape York Peninsula.

“Australian stinging tree species are particularly famous for producing extremely painful stings, which unlike those of their European and American relatives can cause symptoms that last for days or weeks.

“Like other stinging plants such as nettles, the giant spicy tree is covered with needle-like appendages called trichomes that are about five millimeters long; the trichomes look like thin hairs, but actually act as hypodermic needles. which inject toxins when they come in contact with skin, ”said Associate Professor Vetter.

Historically, small trichome molecules such as histamine, acetylcholine, and formic acid have been tested, but their injection does not cause severe and lasting pain in the stinging tree, suggesting that there was an unidentified neurotoxin. .

“We were interested in finding out if there were neurotoxins that could explain these symptoms and why Gympie-Gympie can cause such lasting pain,” said Associate Professor Vetter.







The pain-causing components of giant nettles are miniproteins that modulate ion channels and resemble toxins found in poisonous animals. Credit: Institute for Molecular Bioscience, The University of Queensland

In fact, the team found these neurotoxins, a completely new class of miniproteins they called “Gympietides,” with the plant’s indigenous name.

“Although they come from a plant, gympietides are similar to spider and cone snail toxins in the way they fold into their 3-D molecular structures and target the same pain receptors. this makes the Gympie-Gympie tree a truly “poisonous” plant.

Associate Professor Vetter said the long-lasting pain of the stinging tree can be explained by the fact that gympietids permanently change the sodium channels of sensory neurons, not because the fine hairs stick to the skin.

“By understanding how this toxin works, we hope to provide better treatment to those the plant has stung to relieve or eliminate pain,” he said.

“We can also potentially use gimpietides as scaffolds for new therapies to relieve pain.”

Since these plant and animal toxins have a shared method of causing pain, the question arises of when and how did these toxins evolve?

Researchers point to two possibilities for the evolution of the toxin from an ancestral gene in a shared ancient ancestor or a convergent evolution, where nature reinvents the most appropriate structure to fit a common purpose.

The research team hopes the gimpetids will provide new information on the functioning of pain-sensitive nerves and contribute to the development of new painkillers.


“The worst kind of pain you can imagine”: what it’s like to be stung by a stinging tree


More information:
EK Gilding et al., “Neurotoxic Peptides from the Poor Australian Spicy Tree Poison” Scientific advances (2020). avances.sciencemag.org/lookup … .1126 / sciadv.abb8828

Provided by the University of Queensland



Citation: Toxins from Native Stinging Trees Match Pain in Spiders and Scorpions (2020, September 16) Retrieved September 17, 2020 from https://phys.org/news/2020-09-native-tree- toxins-pain-spiders.html

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