Abstract
Animals using toxic peptides and proteins for predation or defense typically depend on specialized morphological structures, like fangs, spines, or a stinger, for effective intoxication. Here we show that amphibian poisons instead incorporate their own molecular system for toxin delivery to attacking predators. Skin-secreted peptides, generally considered part of the amphibian immune system, permeabilize oral epithelial tissue and enable fast access of cosecreted toxins to the predator’s bloodstream and organs. This absorption-enhancing system exists in at least three distantly related frog lineages and is likely to be a widespread adaptation, determining the outcome of predator–prey encounters in hundreds of species.
Highlights
Animals using toxic peptides and proteins for predation or defense typically depend on specialized morphological structures, like fangs, spines, or a stinger, for effective intoxication
An alternative role in antipredator defense has been suggested, and it was predicted that antimicrobial peptides (AMPs), through a similar cytolytic activity, could permeabilize a predator’s epithelial tissue to facilitate toxin delivery[7]
As the main model for our study, we used a peptide pair composed of the systemic toxin caerulein, and the AMP caerulein precursor b
Summary
Animals using toxic peptides and proteins for predation or defense typically depend on specialized morphological structures, like fangs, spines, or a stinger, for effective intoxication. Co-administration of caerulein and CPF, resembling the natural condition of the frog’s skin secretion, resulted in dose-dependent LDH leakage within 5 min indicating rapid and large-scale damage to cell membranes.
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