Bugs, drugs and electric venom: is this the most deadly library in the world?

after newsletter promotion

To date, snakes have provided the most useful venoms for human drugs and therapies. Scorpions, like Hector, and spiders – which belong to the same class of animals – have long provided useful insights into venom, though no therapeutic compounds have been developed from them. The bugs and drugs group hopes to change that.

Using the venom library, the University of Queensland team, along with scientists from Monash University, have characterised the venom of a subspecies of funnel-web spider, discovering a peptide with potent physiological effects. Known as Hi1a, the tiny protein blocks a signalling pathway that orders cells to die when there’s a lack of oxygen. When given to patients who have suffered a heart attack or stroke, Hi1a could protect against extensive, lasting damage.

In animal models, studies have suggested the molecule may have protective effects against heart attack. It’s slated for preliminary human clinical trials in 2025.

As Hector rests calmly in my palm, Walker explains how his research has seen him move from neuroscience to studying silk proteins, and now to looking beyond scorpions and spiders.

“My idea was that, if you went to a different group of animals that had evolved venom independently, then you would start to see very different types of molecules,” he says.

Walker’s work with caterpillars is at a much earlier stage than the group’s funnel-web studies. Spiders are generally much larger than caterpillars and produce a lot more venom. The typical yield after milking a spider can be measured in microlitres. Venom yield in caterpillars is measured in nanolitres – amounts barely perceptible in a test tube.

King says it would have been impossible to study this amount of venom just 20 years ago but technological advances have enabled researchers to identify peptides from minuscule volumes. This has resulted in a few surprises.

For one, it was predicted that caterpillar venoms would contain simple peptides and proteins – much like bee venoms – because they’re used purely for defence. But Walker’s studies have shown that the molecules produced in caterpillar toxins are much more complex than expected.

In the case of the asp caterpillar, a moth larva which looks like a toupee, Walker found evidence that it may have acquired its toxic capabilities via gene transfer with bacteria many millions of years ago. In research yet to be published, he suggests that the electric caterpillar may have undergone a similar process.

Both species contain venoms rich in molecules which are able to punch holes in a cell membrane, causing an attacking animal to feel pain.

These proteins present a possible path to new insecticides and therapeutics. Similar molecules have been used to protect crops from pests and some are being developed as a way of delivering drugs into cells. The electric caterpillar is unlikely to yield such impact, Walker stresses, but there are immediate benefits of understanding what makes up its venom – especially if you’re a resident of north-east Queensland.

Electric caterpillar envenomation has been notoriously difficult to treat. Ice packs don’t seem to work. An insect bite gel? Forget about it. Vinegar does nothing. Aspirin and paracetamol don’t ease the pain.

Later in the afternoon of my visit, when I’m meeting King and Walker at the university cafe to talk about caterpillars, they devise a potential solution in real time. King notes that pain from jellyfish stings can be alleviated by heat and Walker’s work has shown that peptides in asp caterpillar venom break down at higher temperatures. The electric caterpillar is similar, so they reason that a heat pack might be the best course of action for afflicted patients.

Walker doesn’t seem totally convinced but resolves to email a health worker in north-east Queensland who has been looking for answers. Perhaps he has finally found one.