Ant poison found to mimic echidna hormone
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“To know your enemy, you must become your enemy,” revered Chinese philosopher Sun Tzu once said.
Turns out, though, one of history’s great military strategies is independently employed with distinction by none other than the common Australian bull ant in its daily battle with the ever hungry echidna.
While the ant – technical name Myrmecia Gulosa – is susceptible to individual attack by other carnivorous marsupials such as the bandicoot, only echidnas are known to target its nests and young.
That makes them an enemy worth knowing intimately as far the bull ant is concerned.
In fact two Queensland researchers have discovered the ants, also known as jack jumpers, have to this end, evolved a venom molecule that mimics one of the echidna’s pain hormones.
Coupled with the regular painful bite the ants inflict, the poison is seemingly designed to make the quill-covered monotreme wary about sticking its snout where it doesn’t belong.
But what is short shrift for the echidna may be good news for humans, especially chronic pain sufferers.
“Venoms are complex cocktails,” says Sam Robinson from the uni’s Institute for Molecular Bioscience.
“While bull ant venom contains molecules similar to those found in honey bee stings which cause immediate pain, we also found an intriguing new molecule that was different.”
He and fellow academic David Eagles discovered the molecule matched a sequence of mammalian hormones related to epidermal growth factor and of these, was most closely related to that of the echidna.
Specific testing revealed it to be potent and convinced the pair the venom molecule was there to defend against mammals.
“We went on to show that while it didn’t cause direct pain, the molecule did cause long-lasting hypersensitivity,” Dr Robinson said.
“We think making the echidna sensitive to pain, in tandem with the immediate ‘bee-sting’ pain, may dissuade it from returning to the nests.
“You can see clearly in the ant’s DNA it is producing a molecule that mimics a hormone of its natural enemy and is using it as a weapon against it.”
It’s thought find will help inspire new ways to treat long-term pain.
EGF-inhibitor drugs are readily available on the market and used in anti-cancer therapy to slow tumour growth, with evidence suggesting patients that take them experience less chronic discomfort.
“We hope that by highlighting the role of this signalling pathway in pain, we can encourage different strategies for pain treatment, especially long-term pain for which treatment is currently limited,” Dr Robinson said.
AAP
