Australian stinging trees produce spider and cone snail-like veneers Biology

A team of scientists from the University of Queensland and King’s College London has found that the Australian is poisoned Dendrochnide Trees contain previously unrecognized neurotoxic peptides, and the 3D system of these pain-inducing peptides is reminiscent of spider and cone snail venoms targeting the same pain receptors, thus signaling a significant event in the evolution of animal and plant toxins.

Stinging nettles of the species Dendrochnide Create powerful neurotoxins: (a) Identification in Northern Queensland National Park advises caution around trees; (B) Dendroxide Excelsa Petioles covered with hairs; (C) Scans the electron micrograph of the trichome structure on the leaf Dendroxide moroids; (DG) The cutting reaction that results from an accidental sting Dendroxide moroids Documented with an iPhone XR and NEC G120W2 Thermal Imager, almost instantaneous local psoriasis (arrows on the T), the development of the wheels penetrating the skin (arrows in the Evil), as well as the prolonged action reflex erythema (arrows F and G) Local increase in temperature (degrees Celsius); (H) HPLC chromatogram of trichome extract Dendroxide Excelsa; Diamonds represent nociceptive responses expressed by intraplander administration of individual fractions in vivo in C57BL6 / J mice, with a delayed removal peak identified as the area causing major pain. Image Credit: Irina Wetter, Thomas Durek & Darren Brown, University of Queensland.

Australia despises some of the most venomous animals in the world, but lesser known is its venomous plants.

The Giant stump tree (Dendroxide Excelsa) On the slopes and rocks of the East Australian rainforest some specimens are as high as 35 m (115 ft) in height. However, these are family members Urticase Much more than enlarged nettles.

Of the six species in the genus Dendrochnide Owns sub-tropical and subtropical forests of eastern Australia, the giant deciduous tree and Mulberry-like stinging tree (Dendroxide moroids) Painful sticks are especially infamous for creating symptoms that can last for days or weeks in severe cases.

Like other sting plants such as nettles, the giant sting tree is covered with needle-like appendages called trichomes that are five millimeters long – the trichomes look like fine hairs, but actually act like hypothermic needles that inject toxins when they come in contact with the skin, ”he said. Dr. Irina Wetter, Researcher at the Institute of Molecular Biology at the University of Queensland and at the School of Pharmacy.

Small molecules in trichomes such as histamine, acetylcholine and formic acid have been tested before, but injection of these does not cause severe and chronic pain, suggesting the presence of unidentified neurotoxins.

“We were interested in finding out if there were any neurotoxins that could explain these symptoms, and why Zimbi-Zimbi could cause such chronic pain,” Dr. Wetter said.

Scientists have discovered a completely new type of neurotoxin miniprotein, called ‘zimbidides’. Indigenous name for the plant.

“Although they come from a single plant, zymphides are similar to spider and cone snail toxins that die in their 3D molecular structures and target the same pain receptors – which makes the gimbi-gimbi tree a truly ‘poison’ plant,” said Dr. Wetter.

“Prolonged pain from a stinking tree can be explained by gimbides, which permanently alter the sodium channels in the sensory neurons, but not because the hairs get stuck in the skin.”

“By understanding how this toxin works, we hope to provide the best treatment for those who have been stabbed by the plant, to reduce or eliminate the pain.”

“Zimbidites can be used as scaffolds for new therapies for pain relief.”

The Findings Published in the magazine online Scientific advances.

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Edward K. Guilding And others. 2020. Neurotoxic peptides from the venom of the giant Australian sting tree. Scientific advances 6 (38): eabb8828; doi: 10.1126 / sciadv.abb8828