In this project, we propose to isolate new antimicrobial peptides (AMPs) from two amphibian species native to Portugal. Antimicrobial peptides are promising drug candidates which typically act directly on microorganism?s membranes, bypassing conventional drug resistance strategies. Furthermore, AMPs can be very selective, acting on bacterial membranes but not those of mammals.
 Amphibian secretions are a rich source of diverse AMPs, since they form an important part of their innate immune system.  However, the two species targeted, Pelophylax (P.) perezi and Rana (R.) iberica, have never had the peptides in their secretions studied. This despite the fact that they are closely related to two European frog species which do express AMPs with very useful properties.
This includes a family of peptides which are the shortest AMPs discovered to date, which is a highly desirable characteristic since it greatly reduces production costs. At the same time, this very short peptide inhibited microbial growth at micromolar concentrations. Isolating similar peptides from native Portuguese amphibians would be a very significant find, leading to considerable biotechnological opportunities. We will test the activity of the peptides against various classes of bacteria as well as the parasite Leishmania. In addition, the action of the isolated peptides will be characterised with a range of microscopic and biophysical techniques to provide understanding of their modes of actions. So, in addition to testing against micro-organisms directly, we will measure their interactions with model membranes. These biophysical studies should shed light on the important topic of AMP antimicrobial action in general. 
 We include in our team a consultant who is an expert in the distribution of amphibians in Portugal, and another who is a chromatography expert and has isolated and characterised a large number of AMPs from Brazilian amphibian species. The multidisciplinary team also includes experts in microbiological testing, peptide synthesis, analysis of cells and membranes using atomic force microscopy, and measurement of the interaction between drug candidates and model membranes using biophysical methods. Therefore, the proposed team covers all the areas of expertise required to achieve the goals proposed.
Overall, this project will enable valorisation of Portuguese biodiversity, will identify and characterise potentially useful new molecules for human and veterinary therapy, and aid in understanding two important scientific issues, namely the understanding of the mechanism of action of AMPs, and species diversity in the population of amphibians.