title: Endosymbiotic microflora of the vestimentiferan tubeworm ( Lamellibrachia sp.) from a bathyal cold seep.
abstract: Gutless vestimentiferan tubeworms are known to harbor endosymbiotic bacteria in a specialized tissue, the trophosome, which consists of lobules. The endosymbionts of vestimentiferans inhabiting sulfide-rich hydrothermal vents are monospecific for their host. In contrast, previous studies suggest that vestimentiferas of methane-rich seeps may host multispecific symbionts. Phylogenetic analysis and dot-blot hybridization of 16S ribosomal RNA genes (16S rDNA) detected 4 operational taxonomic units (OTUs) in the trophosome of the vestimentifera Lamellibrachia species from a bathyal methane-seep. The OTUs were closely related to 16S rDNA of the species belonging to alpha -Proteobacteria ( Sulfitobacter), beta- Proteobacteria ( Janthinobacterium), and gamma -Proteobacteria ( Acinetobacter and Pseudomonas). Localizations of the 4 OTUs within the trophosome were confirmed by in situ hybridization (ISH). ISH signals of the alpha-proteobacterial OTU were observed in the innermost zone of the trophosome lobules. In contrast, ISH signals of the beta- and gamma-proteobacterial OTUs were observed at the periphery of the lobules; however, whether they occur inside or outside the lobules remains unclear. These results support the possibility that the studied methane-seep tubeworm has a microflora composed of multispecific endosymbionts.
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004777:Environment; D006652:Histological Techniques; D017403:In Situ Hybridization; D007448:Invertebrates / Q000033:anatomy & histology / Q000382:microbiology*; D008969:Molecular Sequence Data; D009792:Oceans and Seas; D010802:Phylogeny; D020560:Proteobacteria / Q000235:genetics*; D012335:RNA, Ribosomal / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013559:Symbiosis
chemical_list: D017931:DNA Primers; D012335:RNA, Ribosomal