Identification and Antimicrobial Activity of Medium-Sized and Short Peptides from Yellowfin Tuna (Thunnus albacares) Simulated Gastrointestinal Digestion.

Andrea Cerrato,Federico Capuano,Angela Michela Immacolata Montone,Riccardo Zenezini Chiozzi,Susy Piovesana,Carmela Maria Montone,Aldo Laganà,Chiara Cavaliere,Anna Laura Capriotti

doi:10.3390/foods9091185

Abstract

Due to the rapidly increasing resistance to conventional antibiotics, antimicrobial peptides are emerging as promising novel drug candidates. In this study, peptide fragments were obtained from yellowfin tuna muscle by simulated gastrointestinal digestion, and their antimicrobial activity towards Gram-positive and Gram-negative bacteria was investigated. In particular, the antimicrobial activity of both medium- and short-sized peptides was investigated by using two dedicated approaches. Medium-sized peptides were purified by solid phase extraction on C18, while short peptides were purified thanks to a graphitized carbon black sorbent. For medium-sized peptide characterization, a peptidomic strategy based on shotgun proteomics analysis was employed, and identification was achieved by matching protein sequence database by homology, as yellowfin tuna is a non-model organism, leading to the identification of 403 peptides. As for short peptide sequences, an untargeted suspect screening approach was carried out by means of an inclusion list presenting the exact mass to charge ratios (m/z) values for all di-, tri- and tetrapeptides. In total, 572 short sequences were identified thanks to a customized workflow dedicated to short peptide analysis implemented on Compound Discoverer software.

Highlights

Fish is considered the main food source of proteins worldwide; fish proteins have an enormous potential as novel sources of bioactive peptides [1]
antimicrobial peptides (AMPs) are expressed in different fish tissue [12,34], depending on the infective bacteria, and they can display an antibacterial function against antibiotic-resistant bacteria strains
Their antimicrobial capacity is related to some peculiar characteristic, such as the amphipathic structure which is pivotal for the antibacterial activity [33]

Summary

Introduction

Fish is considered the main food source of proteins worldwide; fish proteins have an enormous potential as novel sources of bioactive peptides [1]. The mechanisms of actions which AMPs exhibit are remarkably different from those of commonly used antibiotics, as they are able to fracture bacterial membranes, inhibit the biosynthesis of protein and DNA and other cellular processes, such as protein folding and metabolic turnover [10,11] Thanks to their broad spectrum of mechanisms of action, AMPs show high antimicrobial activity in low concentrations against a broad spectrum of microorganisms, including Gram-positive and Gram-negative bacteria, fungi, and viruses [9]. Their identification and characterization are of great importance for possible use in pharmaceutical and nutraceutical sectors

Methods

Results

Conclusion