Shulou(Shulou.com)11/24 Report--

Photo source: Edward Gilding wants to touch something furry when he sees it, which is not a good habit.

In the tropical rainforest of Australia, there is a kind of shrub called Dendrocnide moroides.

At first glance, it looks nothing special, with broad leaves and fruit like mulberries. If there is any striking feature of this plant, it is that it is furry all over the body, as if it feels good, and it is easy to make people want to touch it.

However, if you really touch it, human beings are likely to regret the unbearable pain. Marina Hurley, an ecologist from Australia, recalled being bitten by a golden bark tree, saying it was as painful as having a baby, or even more painful, as if she had been splashed with acid while burning.

Moreover, the pain caused by this plant is usually long-lasting, not the kind that will pass by after a while. The days of scratching the liver can last for days or weeks, or months. Because this pain is too difficult to get rid of, and sometimes even makes life worse than death, the golden bark tree is affectionately known as the "suicide tree".

What is even more desperate is that even if you do not take the initiative to touch the golden bark tree, you may not be immune from the poisonous hands, especially for those who need to walk through the forest and their horses. Since the 19th century, there have been records of the death of horses caused by golden bark trees. It is also documented that horses that have been "stung" by this plant will become so violent that human beings are unable to defend themselves, so they can only shoot them.

Recently, the plant, which can be tortured for a long time, has been kept at home by a resident of Oxfordshire, England.

It hurts so much. Who did it? The golden bark tree has its name because in the language of the aboriginal Gubbi Gubbi people in Queensland, Australia, thorn trees are called "gimpi-gimpi" and pronounced like "golden skin". But as said at the beginning, the branches and leaves of the golden bark tree are covered with "fluff". It looks obviously soft and amiable, but where does it look like there are thorns?

A gentle appearance may deceive strangers, while experienced locals or research scientists know the power of those "hairs"-they are actually trichomes, which look like thin hairs, but work as sharp as hypodermic needles.

The sharp trichomes of the golden bark tree (photo source: University of Queensland) specifically, the trichomes become sharp instruments in large part because silicon dioxide gives it enough rigidity. On the other hand, there is a small ball at the tip of the hair. as long as it gently touches the skin, the ball will peel off, revealing a sharp needle that can pierce the skin and take advantage of the opportunity to release venom. That's where the pain begins.

These bristles are so small that when they are inserted into the body and broken, the opening in the victim's skin may simply "close" as if it had not been stabbed. Sometimes, it is difficult for the injured who are unfortunately stung by the golden bark tree to take out the poisonous bristles.

Unfortunately, the toxic substances carried by the golden bark tree are very stable and are not easy to decompose. Dr. Marina Hurley, who has been stabbed by the plant, said that even a dry leaf, kept in the specimen room for 100 years, can still cause pain because the toxin has not yet failed.

It looks furry (Photo: Plant Secrets) this is Dr. Hurley's nightmare, but not just hers. For years, scientists have been searching for what is so painful for people and animals. In early studies, molecules such as histamine, acetylcholine and formic acid were suspected. However, after the human body is injected with these substances, the intensity and duration of the pain cannot be compared with the effect of touching the golden bark tree.

There should be other molecules responsible for intense and persistent pain. In the 1970s and 1980s, researchers found a peptide of eight amino acids in the venom of the golden bark tree, which can cause pain when injected subcutaneously. Because the Latin name of the tree is Dendrocnide moroides, the toxin is named moroidin.

Moroidin only accounts for about 0.002% of the leaf crude extract of Chrysanthemum bark. Scientists once believed that this was the root of all evil they were looking for. But later experiments showed that the pain response caused by local injection of 10 micrograms of this substance was not strong, while using the crude extract of leaves directly, 1 microgram was enough to cause severe pain. So, moroidin is probably not the principal culprit.

The prickles of the Australian giant thorn tree D.excelsa (photo: Institute of Molecular Biosciences, University of Queensland) in 2020, a team led by researchers at the University of Queensland identified a new molecular suspect, but first found it in another prickly plant, Dendrocnide excelsa. This is a giant thorn tree, which can sometimes grow to about 40 meters tall, but is related to the low golden bark tree, also from Urticaceae and hemp tree, and has sharp hairs that release painful toxins.

Scientists have isolated a class of unknown pain molecules from the hairs of giant thorn trees, with a much larger molecular weight than the moroidin toxin discovered many years ago. After finding the genes that encode these molecules, the researchers noticed that similar genes were working in the tree, and that these genes in both species were responsible for encoding a peptide of 36 amino acids-a newly discovered toxin family called gympietides.

Some members of the gold skin peptide family, ExTxA-C from the giant thorn tree D. excelsa, MoTxA, from the golden bark tree (photo source: original paper), the researchers synthesized the toxin in the laboratory, diluted with salt water and injected locally into mice. As a result, the pain response of the mice recreated the real scene of being stung by a stinging tree: the mice immediately licked and bit the injected left hind paw and shook or lifted the foot. In addition, although they all belong to the family of golden bark peptides, the effect of synthetic bark tree toxin is more obvious than that of giant thorn tree toxin. As it happens in folk records, being stung by a golden bark tree is also more serious than being stung by a tall stinging tree (the golden bark tree is probably the most painful of all plants in Australia).

Not only that, scientists also found that gold peptides are a kind of binding peptides, in which the inhibitor cystine knot (ICK) helps to ensure the stability of 3D structure. As a result, they remembered that many spider toxins are particularly stable, which is closely related to ICK. The researchers believe that aureopeptide is a hyperstable (ultrastable) toxin, which means it may remain intact for a long time after it enters the body. This may also explain the long-lasting pain after people encounter the golden bark tree.

Some people want to get together, although the venom of this plant is complex, and many of its molecules are associated with pain, in the eyes of scientists, aureopeptide is more likely to cause hell-grade pain than moroidin.

Dr. Marina Hurley once received a letter from an Australian veteran. The letter says he was stung by a stinging tree while crossing a stream in northern Queensland in 1941. Because the pain was so bad, he went crazy like "a cut snake" and was tied to a hospital bed for three weeks. The veteran also said that an officer shot himself because he could not stand the pain because he used the leaves of some kind of thorn tree as toilet paper.

The story of the officer's suicide is famous, but its authenticity is seriously doubted. Generally speaking, the first time you touch a golden leaf, human beings should immediately understand how painful it is, and it is hard to imagine who would continue to use it for other purposes. Of course, even if the story is false, it doesn't stop people from seeing the golden bark tree as a "suicide tree": it's usually not fatal, but it's always excruciating.

Ernie Rider, a botanist, works at the Queensland Park and Wildlife Service (Queensland Parks and Wildlife Service). In 1963, the leaves of the golden bark tree pierced Ryder's face, arms, and chest, and he later recalled:

"for two or three days the pain was so unbearable that I couldn't work or sleep. It was like having a pair of big hands on my chest. The pain was very severe for two weeks. In the next two years, I had a relapse every time I took a cold bath."

In Ryder's eyes, there is nothing worse in life, and he probably doesn't want to meet the golden bark tree a second time. But sometimes, even if people do not come into direct contact with the plant itself, and those needle-like trichomes floating in the air, it is still possible to hurt people.

Also in the 1960s, a researcher named W. V. MacFarlane wrote in an article that he had inhaled some of its trichomes and possibly some dust while studying the golden bark tree. Within 10-15 minutes after that, he began to sneeze.

But sneezing is just the beginning. Three hours after inhaling those prickles, McFarlane developed diffuse pain in the nasopharynx. Twenty-six hours later, I had a sore throat like an inflamed tonsil. The sinuses continue to hurt, and in addition to sneezing, the nose begins to run. Later, the nasal mucosa falls off with blood, pus and some sticky secretions. The excretion of exfoliated tissue lasted for about 10 days.

Later, McFarlane would wear a gas mask when dealing with the golden bark tree. Facing the golden bark tree, the eyes seem to be more resistant than the nose, he said, but dry plant dust may cause some mild conjunctivitis.

Touching is dangerous, breathing around it is not safe, and even looking at it may not be healthy-the golden bark tree is probably such a creature that ordinary people avoid it. But you may remember at the beginning that an Englishman recently started to raise golden bark trees.

The golden bark tree in the cage (photo: Daniel Emlyn-Jones) his name is Daniel Emlin-Jones (Daniel Emlyn-Jones). He received his doctorate from the biology department of University College London more than 20 years ago and did postdoctoral research in Australia. Now he has already returned to England to live and engage in work related to science education. Daniel has always been interested in botany, but he is a little tired of geraniums and thinks it is an interesting idea to keep golden bark trees at home. As a result, he contacted the local media in Oxford and thought they might want to cover it.

As a result, not only the local media wrote the report, but also the media all over the world took action. Now Daniel, who is bothered by media misinterpretation, says he doesn't raise golden bark trees because of the "boring" of life, but just "bored" of geraniums. Daniel also said that he wants to draw more people's attention to botany.

By contrast, the danger of the golden bark tree does not seem to bother him as much as the media. Daniel kept the golden bark tree in a cage with a "DANGER" sign on it with the words: if you get stung, don't rub it with your hands. Daniel said he knew exactly how to deal with the plant.

HealthDirect, Australia's officially funded health service, gave the same warning and explained that if you rub the bitten area, the prickles may sink deeper and it will be more difficult to remove those bristles. If it is a visible bristle, officials recommend pulling it out with tweezers, and if it is for an entire area, you can use wax or duct tape to glue it off.

Of course, the best way is not to encounter this kind of plant, at least for humans and some animals. However, other animals seem to be completely unafraid of the venom of the golden bark tree. The leaves of the golden bark tree are often bitten with holes, and some Australian beetles, which can walk between prickles, seem to be able to avoid danger and eat from the leaves effortlessly. In addition, there is a swamp kangaroo (Thylogale stigmatica), which can even eat all the leaves on a golden tree in a day without any sign of tingling.

Photo Source: Mark Gillow via Wikimedia Commons,CC BY 2. 0 scientists may one day master a special skill that will stop humans from being stung by golden bark trees. But until then, if you like furry creatures, why don't you pet the cat?

Original paper:

Https://www.science.org/doi/10.1126/sciadv.abb8828

Reference:

Https://link.springer.com/article/10.1007/BF02858878

Https://theconversation.com/australian-stinging-trees-inject-scorpion-like-venom-the-pain-lasts-for-days-146115

Https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3153181/

Https://distribution.arte.tv/fiche/SECRETS_DE_PLANTES

Https://www.jstor.org/stable/4252456

Https://www.youtube.com/watch?v=h-sOZ17X8xk

Https://www.youtube.com/watch?v=7MvXfJmRbWQ

Https://www.oxfordmail.co.uk/news/23089713.oxford-man-grows-worlds-dangerous-plant-home/

Https://theconversation.com/the-worst-kind-of-pain-you-can-imagine-what-its-like-to-be-stung-by-a-stinging-tree-103220

Https://www.healthdirect.gov.au/stinging-plants

This article comes from the official account of Wechat: global Science (ID:huanqiukexue), written by: chestnut, revision: Erqi

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.