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sp. nov., a mesophilic sulfate-reducing deltaproteobacterium isolated from a deep siliceous mudstone formationUeno, Akio*; Tamazawa, Satoshi*; Tamamura, Shuji*; Murakami, Takuma*; Kiyama, Tamotsu*; Inomata, Hidenori*; Amano, Yuki; Miyakawa, Kazuya; Tamaki, Hideyuki*; Naganuma, Takeshi*; et al.
International Journal of Systematic and Evolutionary Microbiology, 71(2), p.004683_1 - 004683_10, 2021/02
Times Cited Count：8 Percentile：62.07(Microbiology)A novel mesophilic sulfate-reducing bacterium, designated strain HN2
, was isolated from groundwater sampled from the subsurface Miocene Wakkanai Formation located in Horonobe, Hokkaido, Japan. The cells were Gram-negative rods, with motility conferred by a single polar flagellum. The isolate expressed desulfoviridin, but no catalase or oxidase activities was detected. Strain HN2 grew in a temperature range of 5-43 
C (optimum, 35 C) and in a pH range of 6.5-7.5 (optimum, pH 7.0-7.3). It used sulfate, thiosulfate, dimethyl sulfoxide, anthraquinone-2,6-disulfonate, Fe
, and manganese oxide as electron acceptors, but not elemental sulfur, nitrite, or nitrate. The bacterium showed very weak growth with sulfite as the electron acceptor. The strain fermented pyruvate and cysteine in the absence of sulfate, but not malate or succinate. The bacterium did not require NaCl, but tolerated up to 4% NaCl (w/v). Strain HN2 did not require vitamins. The G+C content of the genomic DNA was 56.66 mol%. A 16S rRNA gene sequence analysis showed that the closest recognized relative of strain HN2 is 
JS1 (97.0% similarity). The average nucleotide identity (ANI) value between strain HN2 and D. 
JS1 was 79.8%. Based on the phenotypic and molecular genetic evidence, the isolate is assigned to the new species sp. nov. The type strain is HN2 (=DSM 101010 =NBRC 112213).
Amano, Yuki; Iwatsuki, Teruki; Naganuma, Takeshi*
Geomicrobiology Journal, 34(9), p.769 - 783, 2017/03
Times Cited Count：6 Percentile：21.84(Environmental Sciences)Two biofilm samples were collected from anaerobic groundwater in a borehole drilled in the Tono area, Japan, to understand the effects of biofilms on the migration behavior of heavy metals in subsurface environments. Biofilms grown on in groundwater of sedimentary rocks and granite groundwater were characterized geochemically and microbiologically, and their heavy metal sorption capability was examined. Clone library analysis was constructed from the biofilms to evaluate microbial community composition. From the results of 16S rRNA gene analyses using clone libraries, it was found that these microbial community compositions in the biofilms were clearly different from the composition of unattached, planktonic microorganisms in the groundwater samples. Furthermore, the microbial community structures generated in each biofilm were different, depending on the groundwater type. It is shown that the community structure of biofilms lacked diversity in groundwater types obtained from sedimentary and granitic rocks. These results indicate that biofilms are formed in natural subsurface environments with site-specific community compositions. High amounts of heavy metals such as Fe, Ni, Cu, Zn, As, Cd, Pb, Th, and U accumulated in the biofilms, and their sorption properties varied in each elements. These results provide important insight on heavy metal sorption capability by biofilms.
Yoshida, Hidekazu; Yamamoto, Koshi*; Amano, Yuki; Katsuta, Nagayoshi*; Hayashi, Toru*; Naganuma, Takeshi
Environmental Geology, 55(6), p.1363 - 1374, 2008/09
Times Cited Count：9 Percentile：26.82(Environmental Sciences)Takashikozo is a phenomenon of Quaternary sediments in Japan. They are cylindrical Fe-oxyhydroxide nodules that form as plaques round plant roots. Structural features suggest that after the roots have decayed, the central space where the roots were situated acts as a flow path for oxidized water. Analysis of microbial 16S rDNA extracted from the nodules identified iron-oxidizing bacteria encrusted round the roots where they are the likely initiators of nodule formation. Geological history and nanofossil evidence suggest that these Fe-nodules may have been buried at a depth of up to several tens of meters for a least 100000 years in reducing Quaternary sediments. Thus Fe-oxyhydroxide nodules with water and rock by microbial mediation can persist under reducing conditions. The phenomenon is significant as an analogue of post-closure conditions in radioactive waste repositories, since it could influence nuclide migration.
Yoshida, Hidekazu; Metcalfe, R.*; Yamamoto, Koshi*; Amano, Yuki; Hoshii, Daisuke*; Kanekiyo, Akiko*; Naganuma, Takeshi*; Hayashi, Toru*
Applied Geochemistry, 23(8), p.2364 - 2381, 2008/08
Times Cited Count：9 Percentile：26.2(Geochemistry & Geophysics)Subsurface redox fronts control the mobilization and fixation of many trace elements. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. The water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-ooxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure.
Nakayama, Shinichi; Nagasaki, Shinya*; Inagaki, Yaohiro*; Oe, Toshiaki*; Sasaki, Takayuki*; Sato, Seichi*; Sato, Tsutomu*; Tanaka, Satoru*; Tochiyama, Osamu*; Nagao, Seiya*; et al.
JAEA-Conf 2007-003, 120 Pages, 2007/03
JAEA-Conf-2007-003.pdf:53.18MB
The 1st information exchange meeting on Radioactive Waste Disposal Research Network was held in Nuclear Science Research Institute of Japan Atomic Energy Agency on August 4, 2006. Radioactive Waste Disposal Research Network was established by under Interorganization Atomic Energy Research Program of Japan Atomic Energy Agency, and the objective is to bring both research infrastructures and human expertise in Japan to an adequate performance level, thereby contributing to the development of the fundamental research area in the field of radioactive waste disposal. This lecture material is a collection of research presentations and discussions during the information exchange meeting.
Naganuma, Takeshi*; Iwatsuki, Teruki; Murakami, Yuki; Hama, Katsuhiro; Okamoto, Takuji*; Tanimoto, Daisuke*; Fujita, Yuka*; Watanabe, Fumiko*; Adachi, Nahomi*; Sato, Makoto*
JNC TY7400 2003-001, 116 Pages, 2003/05
JNC-TY7400-2003-001.pdf:4.97MB
The abundance and diversity of groundwater microorganisms was studied in the Tono area, central Japan. Total cell counts were estimated by epifluorescence microscopy. Cell viability, based on cell membrane integrity, respiration-based metabolism, and esterase activity was estimated to be from 0.001% to approximately 100% of the total counts. The distribution of microbial abundance wad related to a variety of environmental factors, including fracture numbers, hydrological, and geochemical conditions in the groundwater. In the groundwater, profiles of redox sensitive solutes such as sulphate and sulphide ions, abundance and viability of microbes, and sulphur isotope rations of sulphate ions suggest that microbial sulphate redution involving organic matter and subsequent pyrite precipiration are dominant redox reactions at the depths of the uranium ore body. Concentrations of both the sulphate and chloride increase with increasing depth. The dissoloved sulphate is surmised to have originated from dissolution of sulphate and sulphide minerals in a geologic marine formation precipitated in marine environments, in the upper part of the sedimentary rocks. Such a redox process in the water-mineral-microbe system is inferred to have continued from the time when the marine formation underwent uplift above sea-level, because sulphate-reducing bacteria can use sulphate ions dissolved in fresh water that infiltrates from the marine formation and organic matter located in the deeper sedimentary rocks. Calculations by using the sulphate-S contents of the rocks and the sulphate dissolution rate suggest that microbial sulphate redution alone could maintain sufficiently reducing conditions of preserve the uranium ore for several hundred thousand years, in the case where a hydrogeological system continues to exist without much change. On the other hand, iron-oxidizing/reducing bacteria seem to play an important role in iron redox cycling in the granite groundwater.
*; Rajaram, H.*; *;
JNC TY7400 2002-002, 126 Pages, 2002/03
JNC-TY7400-2002-002.pdf:3.13MB
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Iwatsuki, Teruki; Naganuma, Takeshi*
Bios 163, 0 Pages, 2001/00
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*; *; *; *; Iwatsuki, Teruki
JNC TY7400 2000-002, 37 Pages, 2000/05
JNC-TY7400-2000-002.pdf:1.17MB
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Murakami, Yuki*; Naganuma, Takeshi*; Iwatsuki, Teruki
Genshiryoku Bakkuendo Kenkyu, 5(2), p.59 - 66, 1999/03
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Iwatsuki, Teruki; *
International Symposium on Subsurface Microbiology, p.61 - 66, 1999/00
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Naganuma, Takashi; Iwatsuki, Teruki; Shimizu, Satoru*; Akiyama, Masaru*; Ishijima, Yoji*
no journal, ,
Microbial communities affect geochemical and hydrogeological processes in deep aquifers, and have been characterized mainly by genetic approaches as well as activity measurements. We have analyzed 16S rDNA assemblages from hydrologically isolated aquifers of porous-but-less-permeable strata in the northernmost part of Japan, and revealed distinctive microbial communities including methanogens and so-far-uncultured species. We have also collected 16S rDNA of the 0.2-micron m-passing-but-0.1-micron m-captured microorganisms from sedimentary and granite rock aquifers in a uranium deposit area of central Japan. In situ activities are characterized and measured by culture-based physiological approaches, which have many limitations and biases though. We have developed a quantification of mRNA for redox-responsive proteins of Fe(III)-reducing bacteria collected from a deep aquifer. This approach is applicable to other aquifer processes such as reduction of nitrate, sulfate, CO
, etc.
Yasuda, Hiroshi*; Yajima, Kazuaki*; Takada, Masashi*; Nakamura, Takashi*; Fukuda, Mitsuhiro*; Sato, Tatsuhiko; Naganuma, Takeshi*; Onishi, Takeo*
no journal, ,
A novel survey meter for application to future interplanetary exploration has been developed. It is expected that the survey meter will measure separately exact doses of various cosmic-ray particles at any places even on the ground of moon and Mars. This feature surpasses those of other onboard active monitors or present crew personal dosimeters.
Kobayashi, Kensei*; Mita, Hajime*; Nakashima, Satoru*; Yabuta, Hikaru*; Yokobori, Shinichi*; Narumi, Issei; Naganuma, Takeshi*
no journal, ,
no abstracts in English
Tamazawa, Satoshi*; Ueno, Akio*; Tamaki, Hideyuki*; Tamamura, Shuji*; Murakami, Takuma*; Kiyama, Tamotsu*; Inomata, Hidenori*; Miyakawa, Kazuya; Naganuma, Takeshi*; Kaneko, Katsuhiko*
no journal, ,
no abstracts in English
Tamazawa, Satoshi*; Ueno, Akio*; Tamaki, Hideyuki*; Tamamura, Shuji*; Murakami, Takuma*; Kiyama, Tamotsu*; Inomata, Hidenori*; Miyakawa, Kazuya; Naganuma, Takeshi*; Kaneko, Katsuhiko*
no journal, ,
no abstracts in English
Tamazawa, Satoshi*; Ueno, Akio*; Murakami, Takuma*; Miyakawa, Kazuya; Tamamura, Shuji*; Kiyama, Tamotsu*; Inomata, Hidenori*; Naganuma, Takeshi*; Kaneko, Katsuhiko*; Igarashi, Toshifumi*
no journal, ,
no abstracts in English
sp. strain Z1-71, isolated from the terrestrial subsurface environment and its co-cultivation within a methanogenic archaeonUeno, Akio*; Tamazawa, Satoshi*; Tamamura, Shuji*; Murakami, Takuma*; Inomata, Hidenori*; Amano, Yuki; Miyakawa, Kazuya; Naganuma, Takeshi*; Igarashi, Toshifumi*
no journal, ,
no abstracts in English
Ueno, Akio*; Sato, Kiyoshi*; Tamamura, Shuji*; Murakami, Takuma*; Inomata, Hidenori*; Tamazawa, Satoshi*; Amano, Yuki; Miyakawa, Kazuya; Naganuma, Takeshi*; Igarashi, Toshifumi*
no journal, ,
no abstracts in English
