The venom of the Megalopygidae caterpillar has been found to have toxin genes transferred from bacteria. Credit: University of Queensland, Institute for Molecular Bioscience
Key Points:
- Toxins in the venom of caterpillars act in the same way as bacterial toxins.
- The venom’s ability to cut holes through cells could be exploited for drug delivery purposes one day.
- In general, venoms are rich sources of new molecules that could be developed into future medicines, pesticides and more.
Researchers at The University of Queensland have discovered the venom of a notorious caterpillar has a surprising ancestry and could be key to the delivery of drugs.
Andrew Walker, Glenn King and their team discovered that toxins in the venom of asp caterpillars punch holes in cells the same way as toxins produced by disease-causing bacteria such as E. coli and Salmonella.
The asp caterpillar (Megalopyge opercularis) is native to North America, where it is often found in oak or elm trees. It might look innocuous, but its long hair-like bristles conceal venomous spines that can deliver an excruciating sting likened to touching burning coal or blunt force trauma—often sending victims to the hospital.
When the team looked closely at the venom of the asp caterpillar, they were surprised to see it was completely different than anything they had seen before in insects.
“When we looked at it more closely, we saw proteins that were very similar to some of the bacterial toxins that make you sick,” said Walker. “This type of bacterial toxins bind themselves to the surface of cells and assemble into donut-like structures that form holes. It’s similar to the mechanism of box jellyfish venom—and as we’ve now found, caterpillar venom too.”
The scientists say the venom in the caterpillars has evolved via the transfer of genes from bacteria more than 400 million years ago.
Walker and team are interested in understanding the sophisticated ways caterpillars have built a variety of defenses against predators, including cyanide droplets and defensive glues that cause severe pain.
“Venoms are rich sources of new molecules that could be developed into medicines of the future, pesticides, or used as scientific tools,” said Walker.
Specifically, toxins that puncture holes in cells have potential in drug delivery because of their ability to enter cells.
“There may be a way to engineer the molecule to target beneficial drugs to healthy cells, or to selectively kill cancer cells,” concludes Walker.