Cephalopod bacterial associations: characterization and isolation of the symbiotic complex in the Accessory Nidamental Glands

Accessory nidamental glands (ANGs) in the reproductive system of female Myopsidae and Sepioidae (Cephalopoda) host a dense bacterial community in their tubules. Bacteria associated to the ANGs were characterized morphologically and molecularly by complementary approaches: culture dependent (isolation of bacterial strains) and culture independent (direct tissue extraction, sequence comparison of gene for 16S rRNA and fluorescent in situ hybridization). Populations of alpha- and gamma-proteobacteria, Gram-positive bacteria, and Cytophaga-Flavobacteria-Bacteroides were detected in five families of European, Asian and Australian decabrachian cephalopods. in order to obtain bacterial strains difficult to propagate artificially from the host, we have established co-cultures of Sepia officinalis ANG cells with their native bacteria. Cells were maintained viable over one month and the co-cultures contained bacterial strains which could not be cultured in classic microbiological media. Cephalopod cell culture can be used as a new tool to study bacteria-host interactions and their role in the physiology of each partner