EVIDENCE OF ANTIBACTERIAL AND LYSOZYME LIKE ACTIVITY IN DIFFERENT PLANKTONIC LARVAL STAGES OF PARACENTROTUS-LIVIDUS

Larval lysate (four-armed stage) exerts a lysozyme-like and antibacter ial activity directed against Vibrio alginolyticus and other bacterial strains. This lysozyme activity is dependent on the pH and ionic stre ngth of the reacting medium and sample. The other larval stages (six-a rmed, eight-armed and a stage approaching metamorphosis) possess prote ction against bacteria as well. The highest antibacterial activity is present in the six-armed stage. These antibacterial compounds avoid ex ploitation by bacteria. Paracentrotus lividus larvae used in our exper iments were laboratory-reared from specimens collected in 1993 in Port o Cesareo (Lecce, Italy).