Australia Scientists: Stinging Trees Contain 'Scorpion-like Venom'

Burnt tree logs are seen in the fire-grounds near Batemans Bay, Australia January 8, 2020. REUTERS/Alkis Konstantinidis
Burnt tree logs are seen in the fire-grounds near Batemans Bay, Australia January 8, 2020. REUTERS/Alkis Konstantinidis
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Australia Scientists: Stinging Trees Contain 'Scorpion-like Venom'

Burnt tree logs are seen in the fire-grounds near Batemans Bay, Australia January 8, 2020. REUTERS/Alkis Konstantinidis
Burnt tree logs are seen in the fire-grounds near Batemans Bay, Australia January 8, 2020. REUTERS/Alkis Konstantinidis

Australia is notorious for its venomous spiders, snakes and sea creatures, but researchers have now identified "scorpion-like" toxins secreted by a tree that can cause excruciating pain for weeks.

Split-second contact with the dendrocnide tree, a rainforest nettle known by its indigenous name gympie-gympie, delivers a sting far more potent than similar plants found in the US or Europe.

The tree, which has broad oval- or heart-shaped leaves, is primarily found in rainforest areas of northeast Queensland, where it is notorious among hikers.

A team of Australian scientists say they now better understand why the gympie-gympie's sting haunts those unlucky enough to brush up against its leaves.

Victims report an initial sting that "feels like fire at first, then subsides over hours to a pain reminiscent of having the affected body part caught in a slammed car door", the University of Queensland researchers said Thursday.

In the final, drawn-out stages, simply taking a shower can reignite the pain, AFP reported.

Though the gympie-gympie is covered in fine needle-like hairs similar to other nettles, previous testing for common irritants such as histamines came up empty.

Irina Vetter, an associate professor at the University of Queensland's Institute for Molecular Bioscience, said the research team discovered a new class of neurotoxin miniproteins, which they christened 'gympietides'.

"Although they come from a plant, the gympietides are similar to spider and cone snail toxins in the way they fold into their 3D molecular structures and target the same pain receptors -- this arguably makes the gympie-gympie tree a truly 'venomous' plant," she said.

Australia is already infamous for its venomous fauna including snakes, box jellyfish, blue-ringed octopus and funnel-web spiders, although deaths in humans from bites or stings are rare.

Vetter said the long-lasting pain inflicted by the tree may be explained by the gympietides permanently altering the chemical makeup of the affected sensory neurons -- not due to the fine hairs getting stuck in the skin.

The scientists hope their research, published in peer-reviewed journal Sciences Advances, will eventually help lead to better pain relief treatment for people who have been stung.



S.Africa's Iconic Protea Flower Relocates as Climate Warms

Protea flower grower Nico Thuynsma cultivates the blooms north of Johannesburg, 1,500 km (930 miles) from their natural home at the southern tip of Africa. Phill Magakoe / AFP
Protea flower grower Nico Thuynsma cultivates the blooms north of Johannesburg, 1,500 km (930 miles) from their natural home at the southern tip of Africa. Phill Magakoe / AFP
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S.Africa's Iconic Protea Flower Relocates as Climate Warms

Protea flower grower Nico Thuynsma cultivates the blooms north of Johannesburg, 1,500 km (930 miles) from their natural home at the southern tip of Africa. Phill Magakoe / AFP
Protea flower grower Nico Thuynsma cultivates the blooms north of Johannesburg, 1,500 km (930 miles) from their natural home at the southern tip of Africa. Phill Magakoe / AFP

On his farm two hours north of Johannesburg, Nico Thuynsma gestured towards thousands of orange, yellow and pink proteas in flower and thriving 1,500 kilometers (930 miles) from their natural home at the southern tip of Africa.

"They're all different," the 55-year-old farmer said of the assorted blooms from the diverse Proteaceae family that has more than 350 species in South Africa, from firework-like "pincushion" varieties to delicate "blushing brides".

He picked out a majestic pink and white crown, nearly the size of his head, that has taken four years to reach its impressive size. "The King Proteas are very slow to grow," Thuynsma said.

The largest of the proteas, the King Protea, is South Africa's national flower.

It has lent its name to the national cricket team and countless brands. It features on the currency and is the logo for South Africa's presidency this year of the G20 group of leading economies, which convenes a summit in November.

It is also the country's largest flower export with more than 10 million stems sent abroad last year, worth close to 275 million rand ($15 million), according to the Cape Flora industry organization, said AFP.

Its status offers the King Protea some protection but almost half of South Africa's other protea species face extinction because of pressures on their native habitats in the mountains of the Cape, according to South Africa's National Biodiversity Institute (SANBI).

These include habitat loss to agriculture, the proliferation of invasive alien species and "changes to natural fire cycles", SANBI said in a 2021 report.

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"People come to South Africa to see proteas," Nigel Barker, a professor in plant sciences at the University of Pretoria, told AFP. "It's the plant equivalent of the elephant or the lion."

Most proteas are endemic or semi-endemic to the Cape Floral Kingdom biome of "fynbos" ("fine bush") that stretches across the southern tip of South Africa and is one of the world's richest flora biodiversity hotspots.

But climate projections predict "hotter, drier conditions", Barker said. "We'll be looking at a completely different vegetation type in the future, semi-desert almost in some places."

"Many species, because they're so range-restricted, will probably go extinct under those scenarios," he said.

"The only solution we have is to cultivate them artificially... in greenhouses or farms where you control irrigation," Barker said.

An example is Thuynsma's farm in the grasslands of the north, where he began planting proteas three decades ago.

Here, winters are dry and frosty, and the summers rainy -- conditions very different to those in the far south where the proteas are at home.

Gel for irrigation

Through trial and error, Thuynsma has been able to cultivate close to 200 protea varieties, including some long forgotten and abandoned by farmers in their original habitats.

In his latest experiment, he has planted 36 varieties with just two liters (four pints) of saturated gel for irrigation.

"I hope to unlock the power of some of these varieties," Thuynsma said. "They come from the Western Cape out of very harsh conditions, so they do have it in them."

"I learn from them, I learn with them. And, hopefully, in the future I can advise my nursery public -- and even estates -- how to plant this lovely fynbos without irrigation," he said.

"I don't think I have a solution for climate change," he joked, crouched over a small seedling in freshly turned soil. "But I do have a solution: to plant proteas."

A few meters (yards) away, in a warm nursery, thousands of protea sprouts awaited their turn in the soil.

"I love them, I protect them, I collect them," Thuynsma said. "The protea is part of South Africa's DNA."