Morphofunctional characterization and antibacterial activity of haemocytes from<i>Octopus vulgaris</i>

Abstract

This study focused on the morphological and functional characterization of the haemocytes from Octopus vulgaris as the first agents responsible for innate immunity. Three major haemocytes types were identified by light microscopy based on nucleus/cytoplasm ratio and the presence or absence of cytoplasm granules: haemoblast-like cells, hyalinocytes and granulocytes. The presence of three haemocyte populations was also confirmed by flow cytometry. Cytochemical characterization suggests that they perform different activities during humoral responses. Using the plate radial diffusion method we demonstrated the bactericidal activity of haemocytes in the presence of different bacteria strains. To investigate the presence of soluble biotic compounds responsible for antibacterial activity, using a disc diffusion method and the minimum inhibitory concentration, we have also tested the methanolic acid extract from these cells. Our results pave the way for the development of potent antibacterial drugs that could lead to several applications.