title: Functional Classification of Uncultured "Candidatus Caldiarchaeum subterraneum" Using the Maple System.
abstract: In this study, the metabolic and physiological potential evaluator system based on Kyoto Encyclopedia of Genes and Genomes (KEGG) functional modules was employed to establish a functional classification of archaeal species and to determine the comprehensive functions (functionome) of the previously uncultivated thermophile "Candidatus Caldiarchaeum subterraneum" (Ca. C. subterraneum). A phylogenetic analysis based on the concatenated sequences of proteins common among 142 archaea and 2 bacteria, and among 137 archaea and 13 unicellular eukaryotes suggested that Ca. C. subterraneum is closely related to thaumarchaeotic species. Consistent with the results of the phylogenetic analysis, clustering and principal component analyses based on the completion ratio patterns for all KEGG modules in 79 archaeal species suggested that the overall metabolic and physiological potential of Ca. C. subterraneum is similar to that of thaumarchaeotic species. However, Ca. C. subterraneum possessed almost no genes in the modules required for nitrification and the hydroxypropionate-hydroxybutyrate cycle for carbon fixation, unlike thaumarchaeotic species. However, it possessed all genes in the modules required for central carbohydrate metabolism, such as glycolysis, pyruvate oxidation, the tricarboxylic acid (TCA) cycle, and the glyoxylate cycle, as well as multiple sets of sugar and branched chain amino acid ABC transporters. These metabolic and physiological features appear to support the predominantly aerobic character of Ca. C. subterraneum, which lives in a subsurface thermophilic microbial mat community with a heterotrophic lifestyle.
authors.affiliation: Microbial Genome Research Group, Yokohama Institute, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Kanagawa, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Takami
authors.affiliation: Microbial Genome Research Group, Yokohama Institute, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Kanagawa, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Arai
authors.affiliation: Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Iizuka, Fukuoka, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takemoto
authors.affiliation: Laboratory of Genome Informatics, National Institute for Basic Biology, National Institutes of Natural Sciences, Nishigonaka, Myodaiji, Okazaki, Aichi, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Uchiyama
authors.affiliation: Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan; Advanced Science & Innovation Group, Mitsubishi Research Institute Inc. (MRI), Nagata-cho, Chiyoda-ku, Tokyo, Japan.
authors.forename: Takeaki
authors.initials: T
authors.lastname: Taniguchi
mesh_terms: D000641:Ammonia / Q000737:chemistry; D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D001419:Bacteria / Q000235:genetics / Q000378:metabolism; D002241:Carbohydrates / Q000737:chemistry; D057486:Carbon Cycle; D016000:Cluster Analysis; D019295:Computational Biology / Q000379:methods; D030541:Databases, Genetic; D023281:Genomics; D058465:Nitrification; D010641:Phenotype; D010802:Phylogeny; D025341:Principal Component Analysis; D013045:Species Specificity
chemical_list: D002241:Carbohydrates; D000641:Ammonia