Endobiotic bacteria and their pathogenic potential in cnidarian tentacles

Christian Schuett (1) , Hilke Doepke (1)

1 AWI - Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung = Alfred Wegener Institute for Polar and Marine Research = Institut Alfred-Wegener pour la recherche polaire et marine

Endobiotic bacteria colonize the tentacles of cnidaria. This paper provides first insight into the bacterial spectrum and its potential of pathogenic activities inside four cnidarian species. Sample material originating from Scottish waters comprises the jellyfish species hydrozoa and sea anemone Mixed cultures of endobiotic bacteria, pure cultures selected on basis of haemolysis, but also lyophilized samples were prepared from tentacles and used for DGGE-profiling with subsequent phylogenetic analysis of 16S rDNA fragments. Bacteria were detected in each of the cnidarian species tested. Twenty-one bacterial species including four groups of closely related organisms were found in culture material. The species within these groups could not be differentiated from each other (one group of spp., two groups of spp., one group of spp.). Each of the hosts exhibits a specific endobacterial spectrum. Solely harboured Only in , members of the group #2 and the species and were detected. Hydrozoa provided an amazingly wide spectrum of nine bacterial species. Exclusively, in the sea anemone , the bacterial species was found. Overall eleven bacterial species detected were described recently as novel species. Four 16S rDNA fragments generated from lyophilized material displayed extremely low relationship to their next neighbours. These organisms are regarded as members of the endobiotic “terra incognita”. Since the origin of cnidarian toxins is unclear, the possible pathogenic activity of endobiotic bacteria has to be taken into account. Literature data show that their next neighbours display an interesting diversity of haemolytic, septicaemic and necrotic actions including the production of cytotoxins, tetrodotoxin and R-toxin. Findings of haemolysis tests support the literature data. The potential producers are , .

Mots clés: Cnidaria; Tentacles; Endobiotic bacteria; Pathogenic activity; PCR; DGGE

Christian Schuett, Hilke Doepke. Endobiotic bacteria and their pathogenic potential in cnidarian tentacles. Helgoland Marine Research, 2009, 64 (3), pp.205-212. ⟨10.1007/s10152-009-0179-2⟩. ⟨hal-00541672⟩