Ixodes ricinus defensins attack distantly-related pathogens

摘要: Antimicrobial peptides are ubiquitous components of eukaryotic innate immunity. Defensins a well-known family antimicrobial peptides, widely distributed in ticks, insects, plants and mammals, showing activity against bacteria, viruses, fungi, yeast protozoan parasites. Ixodes ricinus is the most common tick species Europe vector pathogens affecting human animal health. Recently, six defensins (including two isoforms) were identified I. ricinus. We investigated evolution defensins. Among five unique defensins, only DefMT3, DefMT5 DefMT6 showed vitro activity. Each defensin was active rather distantly-related bacteria (P < 0.05), significantly among Gram-negative 0.0001). These three represent different clades within suggesting that last ancestor may have had comparable Differences electrostatic potential, amino acid substitutions β-hairpin loop bridging α-helix β-sheet affect DefMT2 DefMT7, which needs to be addressed. Additionally, γ-core motif selected (DefMT3, DefMT6, DefMT7) also tested. Interestingly, compared full length motifs these effective less bacteria. However, antifungal higher than peptides. Our results broaden scope research field highlighting overlooked ability arthropod act microorganisms.