Michael Zasloff, then at the National Institutes of Health, noticed that African clawed frogs recovered from surgical incisions in dirty tank water without infection, and set out to find the chemical reason why.
Zasloff isolated two closely related peptides from frog skin extract and tested them in vitro against a wide range of bacteria, fungi, and protozoa. At low concentrations, the peptides stopped bacteria and fungi and burst protozoa without bursting red blood cells. He named them magainins, from the Hebrew word for shield.
The discovery opened an entirely new field, antimicrobial peptides, now found across nearly every studied animal from insects to humans. A synthetic magainin derivative was tested as a wound treatment in people but never won approval, and cost, stability and safety hurdles have kept most antimicrobial peptides, magainins included, out of the pharmacy so far.
Read the original study
A frog's own shield opened a whole field.
Source
- Zasloff, M. (1987). Magainins, a class of antimicrobial peptides from Xenopus skin: isolation, characterization of two active forms, and partial cDNA sequence of a precursor. Proceedings of the National Academy of Sciences of the United States of America, 84(15), 5449–53. https://doi.org/10.1073/pnas.84.15.5449