Anuran Amphibians: A Huge and Threatened Factory of a Variety of Active Peptides with Potential Nanobiotechnological Applications in the Face of Amphibian Decline

Abstract

All anurans produce venomous skin secretions composed by a complex mixture of bioactive peptides used against potential predators and pathogens that have evolved in a predatorprey interaction and defence against a microbial invasion scenario. Each new species studied reveal new molecules, homologous to hormones, neurotransmitters, antimicrobials, as well as several others with unknown biological activity. The vast majority of species have yet to be studied. Recently, these secretions have also been reported as a rich source of multiple antimicrobial peptides against multidrug-resistant strains of bacteria, fungi, protozoa, and virus, including cancer, providing several instructive lessons for the development of new and more efficient nanotechnology based therapies for infectious disease treatment. However, new drugs arising from the identification and analysis of bioactive peptides from anuran biodiversity are threatened by amphibian decline. Nearly one-third of amphibian species are globally threatened with extinction or extinct due the effects of climate change, reduction and modification of natural habitats, pollution, as well as emerging diseases. Unfortunately, conservation efforts have not been sufficient enough to counter balance the decline in amphibian species. As a result, several species have already become extinct before their peptidome can be evaluated, and others could disappear, which would seriously inhibit understanding required for the development of important new therapies against the superbugs and degenerative diseases. This situation requires drastic strategies in order to build robust anuran peptide libraries and biological anuran tissue banks in order to conserve part of this biological richness. In this chapter, the knowledge of anuran peptide and its potential for the development of new and more effective therapies based on a nanotechnological approach against superbugs that is threatened by amphibian decline are presented.