Characterization of the microbiota from coelomic fluid of the sea urchin Paracentrotus lividus

The study of the microbiota is a subject of considerable and growing interest since it is drawing new important perspectives in the life sciences concerning the functional relationships between metazoans and microbial cells. In fact, it has already shown that the endogenous microbial community affects various physiological activities of multicellular organisms. The coelomic cavity of echinoderms contains a fluid in which coelomocytes are reported to exert immune functions like phagocytosis, opsonization and production of antimicrobial agents against marine bacteria [1, 2]. However, up to day nothing is known about the endogenous bacterial population of coelomic fluid. We focused on this issue, and, to this aim, both bacterial culture-dependent and –independent approaches were adopted. By the former approach, we isolated 8 distinct Gram-negative marine bacterial strains identified for their 16S rDNA sequence. Interestingly, almost all isolated strains show a considerable extracellular hydrolytic activity. Moreover, one of them exerts antimicrobial effect against Gram-negative bacteria, including most of the other strains isolated from the coelomic fluid. Finally, molecular investigation on metagenomic DNA composition is currently ongoing using Next Generation Sequence Technology. This study not only suggests insights on functional interaction between sea urchin and marine microorganisms, but also could provide a novel source of biochemical diversity for the production of bioactive compounds and enzymes that can find biotechnological applications. 1. Remziye Deveci et al. (2015). Journal of Morphology 276(5):583-8 2. Stabili L et al. (1996). Comp Biochem Physiol B Biochem Mol Biol 113(3):639-44