Marine Biotechnology

, Volume 5, Issue 3, pp 261–269

Molecular Characterization and In Situ Localization of Endosymbiotic 16S Ribosomal RNA and RuBisCO Genes in the Pogonophoran Tissue

  • Hiroyuki Kimura
  • Makoto Sato
  • Yuichi Sasayama
  • Takeshi Naganuma
Article

DOI: 10.1007/s10126-002-0073-2

Cite this article as:
Kimura, H., Sato, M., Sasayama, Y. et al. Mar. Biotechnol. (2003) 5: 261. doi:10.1007/s10126-002-0073-2

Abstract

Gutless pogonophorans are generally thought to live in symbiosis with methane-oxidizing bacteria (methanotrophs). We identified a 16S ribosomal RNA gene (rDNA) and a ribulose-1,5-bisphosphate carboxlase/oxygenase (RuBisCO, E.C.4.1.1.39) gene that encode the form I large subunit (cbbL) from symbiont-bearing tissue of the pogonophoran Oligobrachia mashikoi. Phylogenetic analysis of the 16S rDNA sequence suggested that the pogonophoran endosymbiont belonged to the γ-subdivision of Proteobacteria. The endosymbiont was most closely related to an uncultured bacterium from a hydrocarbon seep, forming a unique clade adjacent to the known methanotrophic 16S rDNA cluster. The RuBisCO gene from the pogonophoran tissue was closely related to those of the chemoautotrophic genera Thiobacillus and Hydrogenovibrio. Presence of the RuBisCO gene suggested a methanotrophic symbiosis because some methanotrophic bacteria are known to be capable of autotrophy via the Calvin cycle. In contrast, particulate and soluble methane monooxygenase genes (pmoA and mmoX) and the methanol dehydrogenase gene (mxaF), which are indicators for methanotrophs or methylotrophs, were not detected by repeated trial of polymerase chain reaction. For 16S rRNA and RuBisCO genes, endosymbiotic localizations were confirmed by in situ hybridization. These results support the possibilities that the pogonophoran host has a novel endosymbiont which belongs to the γ-subdivision of Proteobacteria, and that the endosymbiont has the gene of the autotrophic enzyme RuBisCO.

Keywords

pogonophoransendosymbiontphylogenetic analysisDNA-DNA in situ hybridizationchemoautotrophsmethanotrophs

Copyright information

© Springer-Verlag New York Inc. 2003

Authors and Affiliations

  • Hiroyuki Kimura
    • 1
  • Makoto Sato
    • 1
  • Yuichi Sasayama
    • 2
  • Takeshi Naganuma
    • 1
  1. 1.School of Biosphere SciencesHiroshima University, 1-4-4 Kagamiyama Higashi-Hiroshima 739-8528Japan
  2. 2.Noto Marine LaboratoryKanazawa University, Ogi, Uchiura, Ishikawa 927-0553Japan