Isolation and amino acid sequencing by MALDI-TOF-MS/MS of a novel antimicrobial anionic peptide from the skin secretion of Osteocephalus taurinus (Anura, Hylidae)

Abstract

Por meio de técnicas cromatográficas, um novo peptídeo aniônico, denominado otacidina, foi isolado das secreções cutâneas de três anuros brasileiros Osteocephalus taurinus. O sequenciamento de novo dos aminoácidos foi realizado por meio de análises por espectrometria de massas por tempo de vôo acoplada à ionização dessortiva de matriz por laser (MALDI-TOF-MS/MS). O potencial antimicrobiano deste novo metabólito foi avaliado contra cepas de Escherichia coli e Pseudomonas aeruginosa, sendo observadas concentrações inibitórias mínimas (MICs) de 37,4 e 78,4 mM, respectivamente. Este trabalho é apenas o segundo relato de um peptídeo aniônico com propriedades antimicrobianas, isolado da pele de um anfíbio.By means of chromatographic techniques, a novel anionic peptide, named otacidin, was isolated from the skin secretions of tree Brazilian anurans Osteocephalus taurinus. The de novo sequencing of the amino acids was performed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS/MS) analyses. The antimicrobial potential of this novel metabolite was evaluated against Escherichia coli and Pseudomonas aeruginosa, being observed minimum inhibitory concentration (MICs) of 37.4 and 78.4 mM, respectively. This work is just the second report of an antimicrobial anionic peptide from an amphibian.

Manual mass spectrometry de novo sequencing of the anionic host defense peptides of the Cuban Treefrog Osteopilus septentrionalis

“…According to numerous earlier publications and the theory of hard and soft acids/bases, Na + should be attached to one of three Asp residues. 67,68 However, the y-series containing sodium (line 1 of the insert in Figure 3 71,72 The only exception is neutral septenin 2a (Table 2). Some physicochemical and structural properties calculated for the identified septenins 1 and 2 are listed in Table 2.…”

“…Septenins 1 and 2 are anionic peptides with the charge in the range from −1 to −4 at neutral pH, in agreement with previous anionic peptides described from amphibians, including hylid species. 71,72 The only exception is neutral septenin 2a (Table 2). Some physicochemical and structural properties calculated for the identified septenins 1 and 2 are listed in Table 2.…”

Cefepime and Amoxicillin Increase Metabolism and Enhance Caspofungin Tolerance of Candida albicans Biofilms

“…For this purpose, biofilms were formed as described previously for 48 h. Then, biofilms were scraped with sterile tips and the biomass was sonicated. The material was then collected and centrifuged at 9,167 × g for 10 min; supernatants were filtered in 0.22-μm membranes and lyophilized for further analysis (Costa et al, 2012).…”

An Atlas of Anionic Antimicrobial Peptides from Amphibians

“…In contrast, the Manaus slender-legged tree frog, Osteocephalus taurinus, native to many parts of South America and was found to produce octacidin (net charge -2) in its skin secretions. The peptide was predicted to form α-helical secondary structure and exhibited potent activity against a variety of Gram-negative bacteria, including Escherichia coli and Pseudomonas aeruginosa [37]. However, the most studied amphibian producer of AAMPs from South America would appear to be the Mexican giant tree frog, Pachymedusa dacnicolor, which is native to Southern Mexico, a number of dermaseptins have been identified in the amphibian [57].…”