A new study suggests a caterpillar may not just be transforming into a butterfly, but may be transforming the way researchers are delivering drugs and drug design. Researchers at the University of Queensland (UQ), led by Andrew Walker, PhD, a postdoctoral fellow, and Glenn King, PhD, professor from UQ’s Institute for Molecular Bioscience, have discovered the venom of asp caterpillars punches holes in cells the same way as toxins produced by disease-causing bacteria such as E. coli and Salmonella. The findings may lead to new therapeutics or change drug delivery and design.
The findings are published in the Proceedings of the National Academy of Sciences (PNAS) in an article titled, “Horizontal gene transfer underlies the painful stings of asp 3 caterpillars.”
Larvae of the genus Megalopyge (Lepidoptera: Zygaenoidea: Megalopygidae), known as asp or puss caterpillars, produce defensive venoms that cause severe pain. Here, we present the anatomy, chemistry, and mode of action of the venom systems of caterpillars of two megalopygid species, the Southern flannel moth Megalopyge opercularis and the black-waved flannel moth Megalopyge crispata.
“We were surprised to find asp caterpillar venom was completely different to anything we had seen before in insects,” Walker said.
“When we looked at it more closely, we saw proteins that were very similar to some of the bacterial toxins that make you sick.”
This type of bacterial toxin binds itself to the surface of cells and assembles into donut-like structures that form holes.
“The venom in these caterpillars has evolved via the transfer of genes from bacteria more than 400 million years ago.”
“Many caterpillars have developed sophisticated defenses against predators, including cyanide droplets and defensive glues that cause severe pain, and we’re interested to understand how they are all related,” Walker said.
The researchers believe the venoms are rich sources of new molecules that could be developed into medicines of the future, pesticides, or used as scientific tools.
Toxins that puncture holes in cells have particular 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.
