Analysis of the skin secretion of Leptodactylus labyrinthicus, the frog’s biohazard protective clothing

The secretion of amphibians has been used for many years for different purposes such as religion, culture, agro-economics or even as therapeutic agents. Although these secretions are a mixture of different molecules, especially the active peptides therein have been studied intensively during the past 30 years. Peptides have shown to be able to inhibit the growth of different human microorganisms (making from them good candidates for potential therapeutic agents), and soil microorganisms. The objectives of this work was to analyze the secretion of Leptodactylus labyrinthicus in order to identify bioactive peptides, with emphasis on their biological activity in an ecological context. Results reported here shown that, when fractioning the skin secretion of L. labyrinthicus, the growth of Staphylococcus aureus and Burkholderia cepacia were slowly delayed by fractions 8 and 9, but not any delaying effect was observed on Escherichia coli. Interestingly, the whole secretion, have shown a growth promotion for Burkholderia cepacia, but not any effect on Staphylococcus aureus and Escherichia coli. In addition, two peptides already described in the literature, known as Pentadactylin (which inhibit E. coli, P. aeruginosa and S. aureus), and Ocellatin-F1 (which inhibit E.coli and P. aeruginosa), were found in fractions 8 and 9 of this frog skin secretion. In view of these results we hypothesize that, the secretion of Leptodactylus labyrinthicus is a mix of molecules that act in synergy as a bio-regulator mechanism selecting or benefiting microorganisms on the frog’s skin population for ecological, immunological or other purposes not well understood to the moment.