Functional and morphological assessment of glands of patagonian frogs: molecular characterization of prepropeptides and histology of the skin of Odontophrynus occidentalis and Pleurodema somuncurense

MARANI MARIELA M.; CANCELARICH NATALIA L.; PEREZ LUIS O.; BASSO NÉSTOR G.

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Antimicrobial peptides present in amphibian skin are important functional molecules of the innate immune system and play defensive roles against external risk factors. The emergence of multiple strains of pathogenic bacteria resistant to conventional antibiotics has become a serious problem to public health, requiring the search of novel therapeutic molecules. We identified and characterized AMPs in the skin of adult specimens of P. somuncurense (Pso) and O. occidentalis (Ooc). RNA from cephalic-scapular and dorsal skin regions was isolated and their cDNA was obtained. These cDNA were linked to the pCR?4-TOPO vector to transform E.coli DH5α into competent cells. We analyzed and sequenced positive clones, obtaining 11 prepropeptides that codified mature peptides with promising physicochemical features and novel structures. Several presented positive net charge, α-helix structure predicted by 3D software and amphipatic arrangement of the α-helix, which promote their mechanisms of action. Two peptides were similar to the thaulin family peptides, previously described by our group in the skin of the Patagonian frog Pleurodema thaul, while the remaining showed 32-53% percent of similarity when compared with other amphibian AMPs. The peptide synthesis in progress aims at characterizing and evaluating their antimicrobial, hemolytic and cytotoxic activity. Histological analysis of Ooc skin revealed the presence of ordinary mucous glands (OMG) and ordinary serous glands (OSG) in the six studied body regions. Both types of glands shared structural traits common in anurans. OMGs were homogeneously distributed, whereas OSGs showed an heterogeneous distribution and were more numerous in the scapular region. The discovery of these peptides is a promising result in the search of new antimicrobials and highlights the potential of Patagonian species as a novel source of AMPs.