Etude du système immunitaire et du microbiome associé à la peau chez la seiche Sepia officinalis : un potentiel pour l'aquaculture et le domaine maritime
Cephalopods, like the cuttlefish Sepia officinalis, are present in oceans for millions of years. In these animals, only the innate immune system protects the organism from aggressions via a cellular response and a humoral response. Few pathologies have been described in these animals suggesting an effective immune system. Nevertheless, this system remains poorly studied in Cephalopods. Although recognition molecules and signalling pathways have been described, effectors remains unknown. Presence of antibacterial and antioxidant molecules related to the ink, eggs, coproducts of skin or certain bacteria have been uncovered but few have been identified. Thus, the primary objective of the thesis is to describe the cuttlefish’s immune system and to identify humoral factors by studying particularly the white body, the hematopoietic organ, as well as the skin, via transcriptomic, peptidomic and proteomic approaches. In aquatic organisms, skin is coated with mucus sheltering a microbiome, the organism protection is also provided by this biofilm. The second objective is to explore the skin-associated microbiome biodiversity in the cuttlefish, from its establishment in early stages to its degeneration in animals at end of life via metagenomic approach. Lastly, the final objective of this thesis is to explore potential from these new antimicrobials of animal or bacterial origin in aquaculture and on problematics like biofouling and biocorrosion.