title: Distribution, phylogenetic diversity and physiological characteristics of epsilon-Proteobacteria in a deep-sea hydrothermal field.
abstract: Epsilon-Proteobacteria is increasingly recognized as an ecologically significant group of bacteria, particularly in deep-sea hydrothermal environments. In this study, we studied the spatial distribution, diversity and physiological characteristics of the epsilon-Proteobacteria in various microbial habitats in the vicinity of a deep-sea hydrothermal vent occurring in the Iheya North field in the Mid-Okinawa Trough, by using culture-dependent and -independent approaches. The habitats studied were inside and outside hydrothermal plume, and annelid polychaete tubes. In addition, we deployed colonization devices near the vent emission. The polychaete tubes harboured physiologically and phylogenetically diverse microbial community. The in situ samplers were predominantly colonized by epsilon-Proteobacteria. Energy metabolism of epsilon-Proteobacteria isolates was highly versatile. Tree topology generated from the metabolic traits was significantly different (P = 0.000) from that of 16S rRNA tree, indicating current 16S rRNA gene-based analyses do not provide sufficient information to infer the physiological characteristics of epsilon-Proteobacteria. Nevertheless, culturability of epsilon-Proteobacteria in various microbial habitats differed among the phylogenetic subgroups. Members of Sulfurimonas were characterized by the robust culturability, and the other phylogenetic subgroups appeared to lose culturability in seawater, probably because of the sensitivity to oxygen. These results provide new insight into the ecophysiological characteristics of the deep-sea hydrothermal vent epsilon-Proteobacteria, which has never been assessed by comparative analysis of the 16S rRNA genes.
authors.affiliation: Laboratory of Marine Microbiology, Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Oiwake-cho, Kitashirakawa, Kyoto 606-8502, Japan. nakagawas@jamstec.go.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nakagawa
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
authors.forename: Fumio
authors.initials: F
authors.lastname: Inagaki
authors.forename: Hisako
authors.initials: H
authors.lastname: Hirayama
authors.forename: Takuro
authors.initials: T
authors.lastname: Nunoura
authors.forename: Koki
authors.initials: K
authors.lastname: Horikoshi
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Sako
mesh_terms: D003470:Culture Media; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D017753:Ecosystem; D020565:Epsilonproteobacteria / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000502:physiology*; D020459:Genes, rRNA; D014644:Genetic Variation; D006358:Hot Temperature; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S