3% of the ESTs from ‘hit sequences’ group, (2) antimicrobial and

3% of the ESTs from ‘hit sequences’ group, (2) antimicrobial and opioid-like peptides (25.7%), (3) transcripts encoding other protein families (7.9%), and (4) ribosomal and mitochondrial proteins (1.4%). We identified in this work, clusters of homologous sequences from seven different families of peptides, representing 25.7% of valid sequences, whose biological activities are related mainly to antimicrobial effects, as well as to a particular class of peptides with described actions in the nervous system (Table 3). These peptides are relatively selleck chemical short, comprising molecules of 12–100 amino acid

residues long, with diverse composition and mostly highly positively charged. They are expressed in frog skin both constitutively or by inducible mode, in which the Selleck Trichostatin A expression is triggered by the presence of microorganisms or other pro-inflammatory stimuli (Cunliffe and Mahida, 2004). The transcripts described here share a significant similarity to antimicrobial peptides (AMPs) namely dermaseptins, phylloseptins, and tryptophyllins. In addition to that we also observed transcripts encoding opioid peptides such as dermorphins, bradykinin-related peptides (BRPs), and kininogens, herein reported as ‘neuropeptides’ (Fig. 1). Next, in the context of ESTs analysis, a brief discussion

about the structural similarities and biological activities of each peptide family will be presented. Dermorphins have been isolated from Phyllomedusinae frogs and comprise heptapeptides that have high affinity and selectivity for opiate receptors ( Broccardo et al., 1981; Erspamer et al., 1986; Mor et al., 1991; Kreil et al., 1989). First isolated

from Phyllomedusa sauvagii by Montecucchi et al. (1981), dermorphins were shown to present analgesic effect eleven times more potent than morphine in mice ( Broccardo et al., 1981). In this work we found that dermorphins precursors represent the most abundant peptides transcripts in the P. nordestina skin cDNA library ( Fig. 1). Previous work also described a high content of dermorphins in the skin secretion of other members of Phyllomedusinae subfamily ( Melchiori and Negri, 1996). The functional annotation performed here resulted in 12 ESTs sharing similarity to dermorphins, and they were grouped in three contigs. The contigs named DM01 and DM02 share similarities with demorphin-2, for both DNA and deduced protein sequence comparisons. The cDNA HA-1077 mouse structures encoding the contigs sequenced here, DM01 and DM02, presented a signal peptide followed by five repeats of a propeptide and a mature peptide similarly, as observed for the dermorphin-2 from P. sauvagii ( Richter et al., 1990). These contigs shared 80 and 84% of similarity with dermorphin-2 sequence found in databank (GenBank ID: M18031). The contig DM03 also showed similarities with P. sauvagii dermorphin-2, but differences in the number of copy of peptides repeats were observed, i.e. five in DM01 and DM02 sequences, and only three in DM03 ( Fig. 2A).

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