(Umea University) Bacteria release membrane-derived vesicles (MVs), which are small particles that can transport virulence factors to neighbouring bacteria or to the cells of a mammalian host. This special MV-based system for delivering toxic proteins and nucleic acids in a protected manner to the target cells may have different specific functions depending on whether the bacterium acts as an extracellular or intracellular pathogen. This is according to research from Umeå University.