Antifungal properties and membrane-disrupting action of two modified aquatic antimicrobial peptides

Abstract The aim of this study was to evaluate the antifungal spectrum of activity, synergy, and mode of action of carboxy-terminally amidated antimicrobial peptides (AMPs) derived from tachyplesin-I (T-I) from the horseshoe crab Tachypleus tridentatus and a lysine-rich analogue of magainin-2 (MSI-94) from the clawed frog Xenopus laevis. In vitro antimicrobial tests against 17 fungal strains demonstrated that the modified AMPs exhibited broad antifungal activity, particularly against filamentous fungi and yeasts relevant to aquaculture and agriculture. Additive antimicrobial activity was observed with the combination of T-I and MSI-94 against Candida albicans and Rhodotorula mucilaginosa , indicating an enhancement of their antiyeast properties. Furthermore, we found that both peptides target the fungal cell surface, increasing membrane permeability and leading to cell death. Overall, our findings highlight the biotechnological potential of aquatic AMPs in developing novel antifungal therapeutics applicable across various fields.