Diversity of the Antimicrobial Peptide Genes in Collembola

Abstract

Multidrug-resistant bacteria are a current health crisis threatening the world’s population, and scientists are looking for new drugs to combat them. Antimicrobial peptides (AMPs), which are part of the organism’s innate immune system, are a promising new drug class as they can disrupt bacterial cell membranes. This study explored antimicrobial peptide genes in collembola, a non-insect hexapod lineage that has survived in microbe-rich habitats for millions of years, and their antimicrobial peptides have not been thoroughly investigated. We used in silico analysis (homology-based gene identification, physicochemical and antimicrobial property prediction) to identify AMP genes from the genomes and transcriptomes of five collembola representing three main suborders: Entomobryomorpha (Orchesella cincta, Sinella curviseta), Poduromorpha (Holacanthella duospinosa, Anurida maritima), and Symphypleona (Sminthurus viridis). We identified 45 genes belonging to five AMP families, including (a) cysteine-rich peptides: diapausin, defensin, and Alo; (b) linear α-helical peptide without cysteine: cecropin; (c) glycine-rich peptide: diptericin. Frequent gene gains and losses were observed in their evolution. Based on the functions of their orthologs in insects, these AMPs potentially have broad activity against bacteria, fungi, and viruses. This study provides candidate collembolan AMPs for further functional analysis that could lead to medicinal use.

Diversity and Molecular Evolution of Antimicrobial Peptides in Caecilian Amphibians

“…This is likely due to their short sequence length, high variability, and the fact that AMPs often undergo convergent evolution [23]. In addition, the patterns observed for the different candidate AMPs appear to suggest frequent events of gene duplications and losses in caecilians, as found for other amphibians and more distantly related taxa [21,47].…”

“…It is therefore the first study to focus exclusively on the cataloguing and detailed characterisation of the variability of the AMP repertoire in caecilians (and with greater depth and curation effort than in [ 43 ]). In addition, it is one of the first studies to identify candidate caecilian AMPs using whole-genome information, as conducted for other organismal groups by, for example, Pradhan and Engsontia [ 47 ] and Yi et al [ 48 ].…”

“…It is therefore the first study to focus exclusively on the cataloguing and detailed characterisation of the variability of the AMP repertoire in caecilians (and with greater depth and curation effort than in [43]). In addition, it is one of the first studies to identify candidate caecilian AMPs using whole-genome information, as conducted for other organismal groups by, for example, Pradhan and Engsontia [47] and Yi et al [48]. Our main hypothesis is that, given the ~300 million years of independent evolution of caecilians [49,50] and their ecological distinctiveness, mainly due to their fossorial lifestyle, we expect to find in them a high diversity of candidate AMP molecules differentiated from those of other amphibians.…”