Genetic and functional properties of uncultivated thermophilic crenarchaeotes from a subsurface gold mine as revealed by analysis of genome fragments.
Within a phylum Crenarchaeota, only some members of the hyperthermophilic class Thermoprotei, have been cultivated and characterized. In this study, we have constructed a metagenomic library from a microbial mat formation in a subsurface hot water stream of the Hishikari gold mine, Japan, and sequenced genome fragments of two different phylogroups of uncultivated thermophilic Crenarchaeota: (i) hot water crenarchaeotic group (HWCG) I (41.2 kb), and (ii) HWCG III (49.3 kb). The genome fragment of HWCG I contained a 16S rRNA gene, two tRNA genes and 35 genes encoding proteins but no 23S rRNA gene. Among the genes encoding proteins, several genes for putative aerobic-type carbon monoxide dehydrogenase represented a potential clue with regard to the yet unknown metabolism of HWCG I Archaea. The genome fragment of HWCG III contained a 16S/23S rRNA operon and 44 genes encoding proteins. In the 23S rRNA gene, we detected a homing-endonuclease encoding a group I intron similar to those detected in hyperthermophilic Crenarchaeota and Bacteria, as well as eukaryotic organelles. The reconstructed phylogenetic tree based on the 23S rRNA gene sequence reinforced the intermediate phylogenetic affiliation of HWCG III bridging the hyperthermophilic and non-thermophilic uncultivated Crenarchaeota.
Nunoura
Takuro
T
Subground Animalcule Retrieval (SUGAR) Program, Extremebiosphere Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima-cho, Jokosuka, Japan. takuron@jamstec.go.jp
Hirayama
Hisako
H
Takami
Hideto
H
Oida
Hanako
H
Nishi
Shinro
S
Shimamura
Shigeru
S
Suzuki
Yohey
Y
Inagaki
Fumio
F
Takai
Ken
K
Nealson
Kenneth H
KH
Horikoshi
Koki
K
D000332:Aerobiosis; D000445:Aldehyde Oxidoreductases / Q000235:genetics; D019843:Archaeal Proteins / Q000235:genetics; D019615:Crenarchaeota / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D004720:Endonucleases / Q000235:genetics; D020745:Genome, Archaeal; D006046:Gold; D006358:Hot Temperature; D007564:Japan; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics; D019642:RNA, Archaeal; D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012988:Soil Microbiology; D013045:Species Specificity; D014871:Water Microbiology
D019843:Archaeal Proteins; D009097:Multienzyme Complexes; D019642:RNA, Archaeal; D012333:RNA, Messenger; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D006046:Gold; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase; D004720:Endonucleases