Decline of induction capability by outer membrane vesicles on larval metamorphosis of mussels through enzymatic treatments

Outer membrane vesicles (OMVs) are a common bacterial secretion system that facilitates communication between bacteria and hosts, playing a role in the settlement and metamorphosis of some marine larvae. However, the induction mechanism of bacterial OMVs on larval metamorphosis in macrofouling organisms, such as mussels Mytilus coruscus, remains unclear. In this study, we investigated the size, composition, and induction activity of OMVs secreted by various bacteria. Our findings revealed substantial differences in the size, composition, and induction activity of OMVs across different bacterial strains. When correlating the biofilm activity of these strains with the induction activity of their respective OMVs, a significant correlation was observed between the induction activity of OMVs and that of biofilms. Furthermore, our investigation demonstrated that lysozyme, protease, and lipases could decrease the induction activity of OMVs, with lipases exhibiting the most effective inhibitory effect. This research presented a novel approach to inhibit the settlement and metamorphosis of macrofouling by depredating bacterial OMVs.