Identification of a novel antimicrobial peptide,scolopendin 1, derived from centipede Scolopendra subspinipes mutilans and its antifungal mechanism

In this study, a novel antimicrobial peptide, scolopendin 1, was identified from adult centipedes, Scolopendra subspinipes mutilans using RNA sequencing. Scolopendin 1 exerted an antimicrobial activity without inducing haemolysis of human erythrocytes. In order to understand the antifungal mechanism, a reactive oxygen species (ROS) assay was performed, which indicated that scolopendin 1 induced ROS accumulation in Candida albicans. Evaluation of fungal viability using N‐acetyl cysteine, a ROS scavenger, suggested that ROS are a major factor in scolopendin 1‐induced fungal cell death. Co‐staining of annexin V‐fluorescein isothiocyanate (FITC) and propidium iodide, and TUNEL and 4′,6‐diamidino‐2‐phenylindole (DAPI) assays confirmed that ROS‐induced fungal cell death is associated with apoptosis. To further investigate the mechanism that facilitates the progression of apoptosis, changes in intracellular Ca²⁺ concentration and mitochondrial dysfunction were examined. Ca²⁺, a signalling molecule in the apoptotic pathway, was increased in the cytosol and mitochondria, and ROS accumulation triggered mitochondrial depolarization and the release of cytochrome c, a pro‐apoptotic factor, from the mitochondria to the cytosol. Finally, the released cytochrome c activated intracellular caspase. The present study suggests that scolopendin 1 could emerge as a model molecule that targets the apoptotic pathway and provides a novel remedy.