ニシザワ トモヤス
西澤 智康教授
Tomoyasu NISHIZAWA

■研究者基本情報

組織

  • 農学部 食生命科学科
  • 農学研究科(修士課程) 農学専攻 実践農食科学コース
  • 応用生物学野 食生命科学領域

研究分野

  • ライフサイエンス, 植物栄養学、土壌学, 植物栄養学・土壌学
  • ライフサイエンス, 応用微生物学, 応用微生物学
  • ライフサイエンス, 生態学、環境学, 生態・環境
  • 環境・農学, 環境動態解析, 環境動態解析

研究キーワード

  • 分子遺伝学,地圏生態化学,応用環境微生物
  • 遺伝情報解析,比較ゲノミクス
  • バイオスティミュレーション,バイオオーグメンテーション
  • 微生物間相互作用
  • 非リボソーム型ペプチド合成酵素(NRPS),ポリケタイド合成酵素(PKS)

自身の研究に関連するSDGs

学位

  • 2001年03月 博士(農学)(東京農工大学)
  • 1998年03月 修士(農学)(茨城大学)

学歴

  • 2001年03月, 東京農工大学大学院, 連合農学研究科, 生物工学専攻
  • 1998年03月, 茨城大学大学院, 農学研究科, 資源生物科学専攻
  • 1996年03月, 茨城大学, 農学部, 資源生物科学科

経歴

  • 2024年04月 - 現在, 茨城大学農学部, 副学部長
  • 2023年10月 - 現在, 東京農工大学大学院連合農学研究科 兼職, 教授
  • 2023年10月 - 現在, 茨城大学農学部, 教授
  • 2004年 - 2005年, Life Sciences Institute, University of Michigan, Research Fellow
  • 2003年 - 2005年, Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Research Fellow
  • 2001年 - 2003年, Department of Microbiology, Medical School, University of Minnesota, Postdoctoral Research Associate

委員歴

  • 2023年01月 - 現在, Associate Editor, Microbes and Environments
  • 2023年06月 - 2025年05月, 評議員, 日本土壌微生物学会
  • 2023年05月 - 2025年05月, 理事 欧文誌担当, 日本土壌肥料学会
  • 2014年04月 - 2024年03月, 支部会幹事, 日本土壌肥料学会関東支部会
  • 2022年01月 - 2023年05月, 評議員, 日本土壌微生物学会
  • 2021年05月 - 2023年05月, 理事 欧文誌担当, 日本土壌肥料学会
  • 2019年07月 - 2022年12月, Associate Editor, Microbes and Environments
  • 2020年04月 - 2022年03月, 事務局 庶務幹事, 日本土壌肥料学会関東支部会
  • 2018年01月 - 2021年12月, 事務局 総務幹事, 日本土壌微生物学会
  • 2017年01月 - 2020年12月, 評議員, 日本微生物生態学会
  • 2014年10月 - 2018年09月, 欧文誌編集委員, 日本土壌肥料学会
  • 2015年01月 - 2016年12月, 庶務幹事, 日本微生物生態学会

研究者からのメッセージ

  • (研究者からのメッセージ)

     地球の生物圏(地表圏/地圏)では,環境と生物の相互作用によって水,炭素,窒素など生物の生命維持と活動に重要な物質(元素)が循環しています.人間の活動は地球規模での生態系の物質循環に影響を与え,環境問題を引き起こすこともあります.例えば,近代農業では食糧生産性を向上させるために多量の窒素肥料を利用しています.多量の窒素肥料を施用することにより農耕地土壌から温室効果ガスの一つである一酸化二窒素ガスが発生します.さらに,土壌に残った窒素が硝酸に変化して流出し、地下水などを汚染します.硝化と脱窒の過程で一酸化二窒素が生成しますが,いずれも微生物反応に因ります.
     土壌(土壌団粒)に生息する微生物(細菌、古細菌、菌類)は,土壌中の物質循環や環境調整の担い手であり,植物への栄養供給などにも深く関わっています.土壌微生物(群集)の活動が,植物の生育・成長と土壌生態系機能を結びつけています.環境保全・食糧生産・土壌生成に関わる微生物の分子生態学的研究に主として取り組み,土壌や微生物に潜在する機能の解明に向けた研究を行っています.

■研究活動情報

論文

  • Methanotrophic Communities and Cultivation of Methanotrophs from Rice Paddy Fields Fertilized with Pig-livestock Biogas Digestive Effluent and Synthetic Fertilizer in the Vietnamese Mekong Delta
    Huynh Van Thao; Mitsunori Tarao; Hideshige Takada; Tomoyasu Nishizawa; Tran Sy Nam; Nguyen Van Cong; Do Thi Xuan, Japanese Society of Microbial Ecology
    Microbes and Environments, 2024年10月, [査読有り]
  • Methanotrophic Inoculation Reduces Methane Emissions from Rice Cultivation Supplied with Pig-Livestock Biogas Digestive Effluent
    Huynh Van Thao; Mitsunori Tarao; Hideshige Takada; Tomoyasu Nishizawa; Tran Sy Nam; Nguyen Van Cong; Do Thi Xuan, Biogas digestive effluent (BDE) is a nutrient-enriched source that can be utilized as an organic fertilizer for rice cultivation without synthetic fertilizer (SF) application. However, a primary concern is the stimulation of methane (CH4) emissions due to the enrichment of the labile organic carbon, a favorite substrate of methanogenic archaea. Methanotrophs potentially reduce greenhouse gas (GHG) emissions from rice fields owing to metabolizing CH4 as a carbon source and energy. We therefore examined the effect of the application of methanotroph-inoculated BDE to the rice cultivated paddy soil on GHG emissions and rice productivity under a pot experiment. Methanotrophs (Methylosinus sp. and Methylocystis sp.), isolated from the Vietnamese Mekong Delta’s rice fields, were separately inoculated to the heated BDE, followed by a 5-day preincubation. Methanotroph-inoculated BDE was supplied to rice cultivation to substitute SF at 50% or 100% in terms of nitrogen amount. The results showed that the total CH4 emissions increased ~34% with the application of BDE. CH4 emissions were significantly reduced by ~17–21% and ~28–44% under the application of methanotroph-inoculated BDE at 100% and 50%, respectively. The reduction in CH4 was commensurate with the augmentation of pmoA transcript copy number under methanotroph-inoculated BDE. In addition, methanotroph-inoculated BDE application did not increase nitrous oxide (N2O) emissions and adversely affect rice growth and grain productivity. This study highlighted the BDE-recirculated feasibility for a lower CH4 emission rice production based on methanotrophs where high CH4-emitting fields were confirmed., MDPI AG
    Agronomy, 2024年05月, [査読有り]
  • Tardiphaga alba sp. nov., a heavy-metal-tolerant bacterium isolated from garden soil
    Zhihua Bao; Chaojun Wang; Jiahui Cao; Tingting Zhang; Yong Guo; Yoshinori Sato; Tomoyasu Nishizawa; Hiroyuki Ohta, A previously undescribed, heavy-metal-tolerant, motile, Gram-negative bacterium, designated strain SK50-23T, was characterized using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SK50-23T was closely related to Tardiphaga robiniae LMG 26467T and the non-phototrophic ‘Rhodopseudomonas boonkerdii’ NS23T (98.1 and 97.3 % 16S rRNA gene sequence similarity, respectively). Strain SK50-23T possessed a circular genome of 5.86 Mb, with a DNA G+C content of 61.9 mol%. Digital DNA–DNA hybridization showed 20.8–21.6 % similarity between strain SK50-23T and related species. In addition, the whole-genome average nucleotide identity values between strain SK50-23T and related species ranged from 75.1 to 83.5 %. The major cellular fatty acid identified in strain SK50-23T was C18 : 1ω7c, and the main isoprenoid quinone present was ubiquinone Q-10. Strain SK50-23T could be assigned to the genus Tardiphaga with the species name Tardiphaga alba sp. nov. based on morphological, chemotaxonomic and genome-based taxonomic characteristics, and 16S rRNA gene-based phylogenetic characteristics. The type strain of the proposed novel species is SK50-23T (=NBRC 108825T=CGMCC No. 1.12037T)., Microbiology Society
    International Journal of Systematic and Evolutionary Microbiology, 2024年01月, [査読有り]
  • Dark septate endophytic fungi associated with pioneer grass inhabiting volcanic deposits and their functions in promoting plant growth
    Han Sun; Tomoyasu Nishizawa; Hiroyuki Ohta; Kazuhiko Narisawa, Abstract. Growth of the pioneer grass Miscanthus condensatus, one of the first vegetation types to be established on volcanic deposits, is promoted by root-associated fungi, particularly dark septate endophytes (DSEs). Fungal taxa within DSEs colonize the root of Miscanthus condensatus in oligotrophic Andosol, and their function in plant growth promotion remains largely unknown. We, therefore, comprehensively assessed the composition of the DSE community associated with Miscanthus condensatus root in volcanic ecosystems using the approaches of both metabarcoding (next-generation sequencing) and isolation (culturing). Also, the promotion effects of DSEs on plant growth (rice as a proxy) were evaluated by inoculation of core isolates to rice roots. Here, we found the following: (i) 70 % of culturable fungi that colonized Miscanthus condensatus phylogenetically belonged to DSEs; (ii) seven orders were identified by both sequencing and culturing methods; and (iii) inoculation of DSE isolates (Phialocephala fortinii, P. helvetica, and Phialocephala sp.) validated their effects on rice growth, particularly under an extremely low pH condition (compared to the control without inoculation, rice biomass was enhanced 7.6-fold after inoculation of P. fortinii). This study helps improve our understanding of the community of Miscanthus condensatus-associated DSE fungi and their functions in promoting plant growth., Copernicus GmbH
    Biogeosciences, 2023年11月, [査読有り]
  • Detection and isolation of a new member of Burkholderiaceae-related endofungal bacteria from Saksenaea boninensis sp. nov., a new thermotolerant fungus in Mucorales
    Takashima; Y.; K. Yamamoto; Y. Degawa; Y. Guo; T. Nishizawa; H. Ohta; K. Narisawa, Abstract

    Thermotolerance in Mucorales (Mucoromycotina) is one of the factors to be opportunistic pathogens, causing mucormycosis. Among thermotolerant mucoralean fungi, Burkholderiaceae-related endobacteria (BRE) are rarely found and the known range of hosts is limited to Rhizopus spp. The phylogenetic divergence of BRE has recently expanded in other fungal groups such as Mortierellaceae spp. (Mortierellomycotina); however, it remains unexplored in Mucorales. Here, we found a thermotolerant mucoralean fungus obtained from a litter sample collected from Haha-jima Island in the Ogasawara (Bonin) Islands, Japan. The fungus was morphologically, phylogenetically, and physiologically characterized and proposed as a new species, Saksenaea boninensis sp. nov. Besides the fungal taxonomy, we also found the presence of BRE in isolates of this species by diagnostic PCR amplification of the 16S rRNA gene from mycelia, fluorescence microscopic observations, and isolation of the bacterium in pure culture. Phylogenetic analysis of the 16S rRNA gene of BRE revealed that it is distinct from all known BRE. The discovery of a culturable BRE lineage in the genus Saksenaea will add new insight into the evolutional origin of mucoralean fungus-BRE associations and emphasize the need to pay more attention to endofungal bacteria potentially associated with isolates of thermotolerant mucoralean fungi causing mucormycosis., BMC
    IMA Fungus, 2023年11月, [査読有り]
  • イネ種子への微生物接種により水田からのメタン排出を削減する               
    迫田 翠・西澤智康, 責任著者, 北隆館
    アグリバイオ, 2023年11月, [招待有り]
  • Complete genome sequence of Pseudoalteromonas sp. PS1M3, a psychrotrophic bacterium isolated from deep-sea sediment off the Boso Peninsula, Japan Trench
    Yoshihito Nikaidou; Yong Guo; Mahoko Taguchi; Shigeru Chohnan; Tomoyasu Nishizawa; Yasurou Kurusu, 責任著者, Elsevier BV
    Marine Genomics, 2023年06月, [査読有り]
  • Enhanced supply of acetyl-CoA by exogenous pantothenate kinase promotes synthesis of poly(3-hydroxybutyrate)
    Hirotaka Kudo; Sho Ono; Kenta Abe; Mami Matsuda; Tomohisa Hasunuma; Tomoyasu Nishizawa; Munehiko Asayama; Hirofumi Nishihara; Shigeru Chohnan, Abstract

    Background

    Coenzyme A (CoA) is a carrier of acyl groups. This cofactor is synthesized from pantothenic acid in five steps. The phosphorylation of pantothenate is catalyzed by pantothenate kinase (CoaA), which is a key step in the CoA biosynthetic pathway. To determine whether the enhancement of the CoA biosynthetic pathway is effective for producing useful substances, the effect of elevated acetyl-CoA levels resulting from the introduction of the exogenous coaA gene on poly(3-hydroxybutyrate) [P(3HB)] synthesis was determined in Escherichia coli, which express the genes necessary for cyanobacterial polyhydroxyalkanoate synthesis (phaABEC).

    Results

    E. coli containing the coaA gene in addition to the pha genes accumulated more P(3HB) compared with the transformant containing the pha genes alone. P(3HB) production was enhanced by precursor addition, with P(3HB) content increasing from 18.4% (w/w) to 29.0% in the presence of 0.5 mM pantothenate and 16.3%–28.2% by adding 0.5 mM β-alanine. Strains expressing the exogenous coaA in the presence of precursors contained acetyl-CoA in excess of 1 nmol/mg of dry cell wt, which promoted the reaction toward P(3HB) formation. The amount of acetate exported into the medium was three times lower in the cells carrying exogenous coaA and pha genes than in the cells carrying pha genes alone. This was attributed to significantly enlarging the intracellular pool size of CoA, which is the recipient of acetic acid and is advantageous for microbial production of value-added materials.

    Conclusions

    Enhancing the CoA biosynthetic pathway with exogenous CoaA was effective at increasing P(3HB) production. Supplementing the medium with pantothenate facilitated the accumulation of P(3HB). β-Alanine was able to replace the efficacy of adding pantothenate., Springer Science and Business Media LLC
    Microbial Cell Factories, 2023年04月, [査読有り]
  • A Nitrate-Transforming Bacterial Community Dominates in the Miscanthus Rhizosphere on Nitrogen-Deficient Volcanic Deposits of Miyake-jima
    Ahmad Arsyadi; Yong Guo; Akiko Ebihara; Nobuo Sakagami; Midori Sakoda; Kanako Tago; Takashi Kamijo; Hiroyuki Ohta; Tomoyasu Nishizawa, ラスト(シニア)オーサー, The perennial gramineous grass Miscanthus condensatus functions as a major pioneer plant in colonizing acidic volcanic deposits on Miyake-jima, Japan, despite a lack of nitrogen nutrients. The nitrogen cycle in the rhizosphere is important for the vigorous growth of M. condensatus in this unfavorable environment. In the present study, we identified the nitrogen-cycling bacterial community in the M. condensatus rhizosphere on these volcanic deposits using a combination of metagenomics and culture-based analyses. Our results showed a large number of functional genes related to denitrification and dissimilatory nitrate reduction to ammonium (DNRA) in the rhizosphere, indicating that nitrate-transforming bacteria dominated the rhizosphere biome. Furthermore, nitrite reductase genes (i.e., nirK and nirS) related to the denitrification and those genes related to DNRA (i.e., nirB and nrfA) were mainly annotated to the classes Alpha-proteobacteria, Beta-proteobacteria, and Gamma-proteobacteria. A total of 304 nitrate-succinate-stimulated isolates were obtained from the M. condensatus rhizosphere and were classified into 34 operational taxonomic units according to amplified 16S rRNA gene restriction fragment pattern analysis. Additionally, two strains belonging to the genus Cupriavidus in the class Beta-proteobacteria showed a high in vitro denitrifying activity; however, metagenomic results indicated that the DNRA-related rhizobacteria appeared to take a major role in the nitrogen cycle of the M. condensatus rhizosphere in recent Miyake-jima volcanic deposits. This study elucidates the association between the Miscanthus rhizosphere and the nitrate-reducing bacterial community on newly placed volcanic deposits, which furthers our understanding of the transformation of nitrogen nutrition involved in the early development of vegetation., MDPI AG
    Microorganisms, 2023年01月, [査読有り]
  • Mitigation of paddy field soil methane emissions by betaproteobacterium Azoarcus inoculation of rice seeds
    Sakoda; M.; T. Tokida; Y. Sakai; K. Senoo; T. Nishizawa, ラスト(シニア)オーサー, Sakoda, M., T. Tokida, Y. Sakai, K. Senoo, T. Nishizawa, JSME, JSSM, TSME, JSPMI, JSE
    Microbes Environ., 2022年12月, [査読有り]
  • Long-term no-tillage and rye cover crop affect soil biological indicators on Andosols in a humid, subtropical climate
    Gong; Y.; P. Li; Y. Guo; H. Aso; Q. Huang; H. Araki; T. Nishizawa; M. Komatsuzaki, WILEY
    Eur. J. Soil Sci., 2022年10月, [査読有り]
  • Complete genome sequence of a psychrophilic bacterium, Pseudoalteromonas sp. strain APM04, isolated from the seafloor of the South Mariana Trough, Pacific Ocean
    Taguchi; M.; Y. Guo; T. Nishizawa; S. Chohnan; Y. Kurusu, 責任著者, The complete genome sequence of Pseudoalteromonas sp. strain APM04, which is a psychrophilic bacterium that inhabits the seabed of the South Mariana Trough, Pacific Ocean, was determined to characterize the genetic features associated with evolution in extremophilic and oligotrophic deep seawater., Am Soc Microbiol
    Microbiol. Resour. Ann., 2022年08月, [査読有り]
  • No Tillage Increases SOM in Labile Fraction but Not Stable Fraction of Andosols from a Long-Term Experiment in Japan
    Jeannette Aduhene-Chinbuah; Soh Sugihara; Masakazu Komatsuzaki; Tomoyasu Nishizawa; Haruo Tanaka, No tillage (NT) fosters carbon (C) sequestration, increases soil organic matter (SOM) stock, and improves soil health. However, its effect on SOM accumulation in Andosol, which has high OM stabilization characteristics due to its specific mineral properties, remains unclear. In this study, we evaluated the effect of NT on SOM content and its distribution by the physical fractionation method and assessed the quality of accumulated SOM in each fraction. We collected soil samples at 0–2.5, 2.5–7.5, and 7.5–15 cm depths from NT and conventional tillage (CT) plots in a long-term (19 years) field experiment of Andosols in Ibaraki, Japan. The soil samples were separated into light fraction (LF), coarse-POM (cPOM: 0.25–2 mm), fine-POM (fPOM: 0.053–0.25 mm), and silt + clay (mOM: <0.053 mm). The C, nitrogen (N), and organic phosphorus (Po) contents of each fraction were analyzed. The C content of cPOM and fPOM in NT at 0–7.5 cm was higher than in CT, while there was no clear difference in the mOM fraction or deeper layer (7.5–15 cm). NT increased the C, N, and Po contents in the labile POM fractions at the surface layers but did not increase the stable fraction or change the quality., MDPI AG
    Agronomy, 2022年02月, [査読有り]
  • Whole-Genome Sequence of Entomortierella parvispora E1425, a Mucoromycotan Fungus Associated with Burkholderiaceae -Related Endosymbiotic Bacteria
    Afri Herlambang; Yong Guo; Yusuke Takashima; Kazuhiko Narisawa; Hiroyuki Ohta; Tomoyasu Nishizawa, ラスト(シニア)オーサー, Some mucoromycotan fungi establish symbiotic associations with endohyphal bacteria. Here, the genome of Entomortierella parvispora E1425 (synonymously known as Mortierella parvispora E1425), which harbors a cultured Burkholderiaceae -related endobacterium (BRE) designated Mycoavidus sp. Strain B2-EB, was sequenced. We provide genomic information to elucidate fungal-BRE symbiotic features., American Society for Microbiology
    Microbiology Resource Announcements, 2022年01月, [査読有り]
  • Complete Genome Sequence of a Chemolithoautotrophic Iron-Oxidizing Bacterium, Acidithiobacillus ferrooxidans Strain NFP31, Isolated from Volcanic Ash Deposits on Miyake-Jima, Japan
    Tatsuhiro Kato; Yong Guo; Reiko Fujimura; Takamichi Nakamura; Tomoyasu Nishizawa; Yasuro Kurusu; Hiroyuki Ohta, 責任著者, The genome sequence of Acidithiobacillus ferrooxidans strain NFP31, which is a chemolithoautotrophic iron-oxidizing bacterium that inhabits acidified volcanic deposits on Mount Oyama, Miyake Island (Miyake-jima), Japan, was determined to identify the genetic characteristics associated with pioneer microbes in newly placed pyroclastic deposits., American Society for Microbiology
    Microbiology Resource Announcements, 2022年01月, [査読有り]
  • Root bacteriome of a pioneer grass Miscanthus condensatus along restored vegetation on recent Miyake-jima volcanic deposits
    Yong Guo; Tomoyasu Nishizawa; Nobuo Sakagami; Reiko Fujimura; Takashi Kamijo; Hiroyuki Ohta, 責任著者, Elsevier BV
    Rhizosphere, 2021年09月, [査読有り]
  • 土壌微生物と気候変動
    太田寛行・西澤智康, 日本土壌微生物学会
    土と微生物, 2021年04月, [査読有り], [招待有り]
  • 糸状菌に内生する細菌の縮小化ゲノムの特徴
    郭永・高島勇介・西澤智康, ラスト(シニア)オーサー, (一財)バイオインダストリー協会
    B&I (バイオサイエンスとインダストリー), 2021年03月, [招待有り]
  • Mycoavidus sp. Strain B2-EB: Comparative Genomics Reveals Minimal Genomic Features Required by a Cultivable Burkholderiaceae -Related Endofungal Bacterium
    Yong Guo; Yusuke Takashima; Yoshinori Sato; Kazuhiko Narisawa; Hiroyuki Ohta; Tomoyasu Nishizawa, ラスト(シニア)オーサー, This study attempted the isolation of a novel endobacterium, Mycoavidus sp. B2-EB (JCM 33615), harbored in the fungal host Mortierella parvispora E1425 (JCM 39028). We report the complete genome sequence of this strain, which possesses a reduced genome size with relatively high genome completeness and a streamlined genome structure. The information indicates the minimal genomic features required by both the endofungal lifestyle and artificial cultivation, which furthers our understanding of genome reduction in fungal endosymbionts and extends the culture resources for biotechnological development on engineering synthetic microbiomes., American Society for Microbiology
    Applied and Environmental Microbiology, 2020年09月, [査読有り]
  • 土壌団粒構造と土壌プロセス2—実測と理論の統合を目指して—
    荒井見和・多胡香奈子・和穎朗太・取出伸夫・青山正和・ 西澤智康・金子信博・松岡健介・太田寛行, 一般社団法人日本土壌肥料学会
    日本土壌肥料学雑誌, 2020年08月, [査読有り], [招待有り]
  • Aposymbiosis of a <i>Burkholderiaceae</i>-Related Endobacterium Impacts on Sexual Reproduction of Its Fungal Host
    Yusuke Takashima; Yousuke Degawa; Tomoyasu Nishizawa; Hiroyuki Ohta; Kazuhiko Narisawa, Japanese Society of Microbial Ecology
    Microbes and Environments, 2020年, [査読有り]
  • Genome Sequence of Novoherbaspirillum sp. UKPF54, a Plant Growth-Promoting Rhizobacterial Strain with N2O-Mitigating Abilities, Isolated from Paddy Soil
    Nan Gao; Chaowei Zhou; Weishou Shen; Sayuri Ota; Yutaka Shiratori; Tomoyasu Nishizawa; Kazuo Isobe; Xinhua He; Hanjie Ying; Keishi Senoo, Am Soc Microbiol
    Microbiology Resource Announcements, 2020年01月, [査読有り]
  • 糸状菌ー内生細菌の微生物間相互作用現象の解明
    西澤智康, 公益財団法人 発酵研究所
    IFO Res. Commun., 2019年12月, [査読有り], [招待有り]
  • Genome Sequence of Arthrobacter sp. UKPF54-2, a Plant Growth-Promoting Rhizobacterial Strain Isolated from Paddy Soil
    Weishou Shen; Xinchun Yu; Nan Gao; Sayuri Ota; Yutaka Shiratori; Tomoyasu Nishizawa; Kazuo Isobe; Xinhua He; Keishi Senoo, Arthrobacter sp. strain UKPF54-2, a plant growth-promoting rhizobacterium having the potential ability to control fungal and bacterial pathogens, was isolated from paddy soil in Kumamoto, Japan. We report here the whole-genome sequence of this strain., American Society for Microbiology
    Microbiology Resource Announcements, 2019年11月, [査読有り]
  • Azoarcus sp. strain KH32C affects rice plant growth and the root-associated soil bacterial community in low nitrogen input paddy fields
    Midori Sakoda; Maika Mizusawa; Fumitaka Shiotsu; Nobuo Sakagami; Yong Guo; Yuji Masutomi; Daichi Fujii; Kazuo Isobe; Toru Fujiwara; Keishi Senoo; Tomoyasu Nishizawa, ラスト(シニア)オーサー, Informa UK Limited
    Soil Science and Plant Nutrition, 2019年09月, [査読有り]
  • Genome Sequences of Two Azospirillum sp. Strains, TSA2S and TSH100, Plant Growth-Promoting Rhizobacteria with N 2 O Mitigation Abilities
    Nan Gao; Weishou Shen; Tomoyasu Nishizawa; Kazuo Isobe; Yong Guo; Hanjie Ying; Keishi Senoo, Azospirillum sp. strains TSA2S and TSH100 are plant growth-promoting rhizobacteria with the capacity to mitigate N 2 O from agricultural soil. They were isolated from the rhizosphere of paddy soil in Tokyo, Japan. Here, we present the genome sequences of these two strains., American Society for Microbiology
    Microbiology Resource Announcements, 2019年08月, [査読有り]
  • Comparative Characterization of Bacterial Communities in Moss-Covered and Unvegetated Volcanic Deposits of Mount Merapi, Indonesia
    Annisa N. Lathifah; Yong Guo; Nobuo Sakagami; Wataru Suda; Masanobu Higuchi; Tomoyasu Nishizawa; Irfan D. Prijambada; Hiroyuki Ohta, Japanese Society of Microbial Ecology
    Microbes and Environments, 2019年, [査読有り]
  • Comparative Analysis of the Genetic Basis of Branched Nonylphenol Degradation by Sphingobium amiense DSM 16289T and Sphingobium cloacae JCM 10874T
    Mina Ootsuka; Tomoyasu Nishizawa; Morifumi Hasegawa; Yasurou Kurusu; Hiroyuki Ohta, Japanese Society of Microbial Ecology
    Microbes and Environments, 2018年12月, [査読有り]
  • Prevalence and intra-family phylogenetic divergence of Burkholderiaceae-related endobacteria associated with species of Mortierella
    Takashima, Y; K. Seto; Y. Degawa; Y. Guo; T. Nishizawa; H. Ohta; K. Narisawa, JSME, JSSM
    Microbes Environ., 2018年12月, [査読有り]
  • 植物-土壌脱窒細菌間相互作用を担う新奇シグナル物質の同定
    西澤智康, 筆頭著者, 公益財団法人 タカノ農芸化学研究助成財団
    平成29年度 助成研究報告書, 2018年12月, [招待有り]
  • 霞ヶ浦周辺環境における薬剤耐性菌の分布
    矢用もも・平野明則・松田祐輝・上原研人・今井達也・島袋 真・黒田久雄・太田寛行・西澤智康, 責任著者, 17th World Lake Conference
    17th World Lake Conference, Lake Kasumigaura, 2018年10月
  • 低窒素施用水田土壌での脱窒細菌接種によるイネ生育促進効果:イネ栽培調査と根域土壌細菌叢解析
    迫田 翠・水澤舞花・塩津文隆・郭 永・坂上伸生・滝本貴弘・増冨祐司・藤原 徹・妹尾啓史・西澤智康, 責任著者, 17th World Lake Conference
    17th World Lake Conference, Lake Kasumigaura, 2018年10月
  • Soil environmental condition and vegetation recovery of the abandoned cropland around Komado-shitsugen moor, Fukushima prefecture
    Sakagami; N.; Y. Guo; Y. Takashima; T. Nishizawa; K. Narisawa; M. Watanabe, 17th World Lake Conference
    17th World Lake Conference, Lake Kasumigaura, 2018年10月
  • 平成27年9月関東・東北豪雨の影響を受けた土壌の無機元素組成および細菌群集構造解析
    齋藤明葉・坂上伸生・成澤才彦・伊藤哲司・西澤智康, 責任著者, 17th World Lake Conference
    17th World Lake Conference, Lake Kasumigaura, 2018年10月
  • Presence of both Cu-type (NirK) and cd1-type (NirS) nitrite reductase genes in a denitrifying bacterium Bradyrhizobium nitroreducens sp. nov.
    Jeonghwan J; N. Ashida; A. Kai; K. Isobe; T. Nishizawa; S. Otuka; A. Yokota; K. Senoo; S. Ishii, JSME, JSSM
    Microbes Environ., 2018年10月, [査読有り]
  • Complete genome sequence of a microcystin-degrading bacterium Sphingosinicella microcystinivorans strain B-9
    Jin, H; T. Nishizawa; Y. Guo; A. Nishizawa; H.-D. Park; H. Kato; K. Tsuji; K.-I. Harada, Am Soc Microbiol
    Microbiol. Resour. Announc., 2018年09月, [査読有り]
  • Complete Genome Sequence of the Nonheterocystous Cyanobacterium Pseudanabaena sp. ABRG5-3.
    Naoyuki Tajima; Yu Kanesaki; Shusei Sato; Hirofumi Yoshikawa; Fumito Maruyama; Ken Kurokawa; Hiroyuki Ohta; Tomoyasu Nishizawa; Munehiko Asayama; Naoki Sato, We report here the complete sequences of the main genome (4.8 Mb) and seven plasmids of the semifilamentous, nonheterocystous cyanobacterium Pseudanabaena sp. ABRG5-3, a strain isolated from a pond in Japan. These data are expected to enhance our understanding of the Pseudanabaena subclade near the root of cyanobacterial diversity., Am Soc Microbiol
    Genome announcements, 2018年02月, [査読有り]
  • Effects of Rhizobium Species Living with the Dark Septate Endophytic Fungus Veronaeopsis simplex on Organic Substrate Utilization by the Host
    Yong Guo; Yuuto Matsuoka; Tomoyasu Nishizawa; Hiroyuki Ohta; Kazuhiko Narisawa, Japanese Society of Microbial Ecology
    Microbes and Environments, 2018年, [査読有り]
  • Comparative Genomic Insights into Endofungal Lifestyles of Two Bacterial Endosymbionts, Mycoavidus cysteinexigens and Burkholderia rhizoxinica
    Dilruba Sharmin; Yong Guo; Tomoyasu Nishizawa; Shoko Ohshima; Yoshinori Sato; Yusuke Takashima; Kazuhiko Narisawa; Hiroyuki Ohta, Japanese Society of Microbial Ecology
    Microbes and Environments, 2018年, [査読有り]
  • FVIIa-sTF and Thrombin Inhibitory Activities of Compounds Isolated from Microcystis aeruginosa K-139
    Andrea Roxanne J. Anas; Akane Mori; Mineka Tone; Chiaki Naruse; Anna Nakajima; Hirohiko Asukabe; Yoshiaki Takaya; Susumu Y. Imanishi; Tomoyasu Nishizawa; Makoto Shirai; Ken-ichi Harada, The rise of bleeding and bleeding complications caused by oral anticoagulant use are serious problems nowadays. Strategies that block the initiation step in blood coagulation involving activated factor VII-tissue factor (fVIIa-TF) have been considered. This study explores toxic Microcystis aeruginosa K-139, from Lake Kasumigaura, Ibaraki, Japan, as a promising cyanobacterium for isolation of fVIIa-sTF inhibitors. M. aeruginosa K-139 underwent reversed-phase solid-phase extraction (ODS-SPE) from 20% MeOH to MeOH elution with 40%-MeOH increments, which afforded aeruginosin K-139 in the 60% MeOH fraction; micropeptin K-139 and microviridin B in the MeOH fraction. Aeruginosin K-139 displayed an fVIIa-sTF inhibitory activity of similar to 166 mu M, within a 95% confidence interval. Micropeptin K-139 inhibited fVIIa-sTF with EC50 10.62 mu M, which was more efficient than thrombin inhibition of EC50 26.94 mu M. The thrombin/fVIIa-sTF ratio of 2.54 in micropeptin K-139 is higher than those in 4-amidinophenylmethane sulfonyl fluoride (APMSF) and leupeptin, when used as positive controls. This study proves that M. aeruginosa K-139 is a new source of fVIIa-sTF inhibitors. It also opens a new avenue for micropeptin K-139 and related depsipeptides as fVIIa-sTF inhibitors., MDPI AG
    MARINE DRUGS, 2017年09月, [査読有り]
  • Nitrous oxide (N2O)-reducing denitrifier-inoculated organic fertilizer mitigates N2O emissions from agricultural soils
    Nan Gao; Weishou Shen; Estefania Camargo; Yutaka Shiratori; Tomoyasu Nishizawa; Kazuo Isobe; Xinhua He; Keishi Senoo, Springer Science and Business Media LLC
    Biology and Fertility of Soils, 2017年08月, [査読有り]
  • 石人山古墳装飾石棺表面に形成した着生生物群集の構造解析
    佐藤嘉則・西澤智康・小沼奈那美・犬塚将英・森井順之・木 川りか・朽津信明, Sekijinsan Tumulus in Hirokawa, Fukuoka prefecture is a keyhole-shaped burial mound with a decorated stone sarcophagus that was built in the first half of the 5th century. Recently, green epiphytic organisms have spread widely on the western side of the sarcophagus surface, preventing preservation and exhibition to the public. The aim of the present study was to analyze the epiphytic microbial community by using molecular techniques to determine the algal, fungal and bacterial community structures on the sarcophagus surface. The algal gene sequences closely related to those of nitrogen-fixing Tolypothrix distorta and salt-tolerant Halospirulina were detected. The environmental factors of limited nitrogen source,solar radiation,and dry and salty conditions were considered to have contributed to the ability of these algae to grow on the sarcophagus surface.Moreover, algal gene sequences closely related to that of Cyanidium were detected. The genus Cyanidium is a red algal extremophile which typically grows in acidic hot springs. It is known that organisms related to such an evolutionarily old red alga are able to grow on the stone sarcophagus surface. In fungal community structure analysis, sequences closely related to Mariannaea elegans and Trichoderma virens were commonly and frequently observed. In bacterial community structure analysis, Arthrobacter russicus, Sphingomonas leidyi and Brevundimonas vesicularis were commonly detected. In the present study,by using a molecular biology approach,the community structures of microorganisms on the stone sarcophagus surface were clarified. However, these community structures are expected to change even under natural conditions,depending on the surrounding environment that is influenced by annual and seasonal fluctuations or the growth of trees. With these changes, it is important to conduct ongoing surveys while continuing studies on biological control methods., 保存科学研究センター
    保存科学, 2017年03月, [査読有り]
  • Actinophage R4 integrase-based site-specific chromosomal integration of non-replicative closed circular DNA
    Takamasa Miura; Akito Nishizawa; Tomoyasu Nishizawa; Munehiko Asayama; Makoto Shirai, The actinophage R4 integrase (Sre)-based molecular genetic engineering system was developed for the chromosomal integration of multiple genes in Escherichia coli. A cloned DNA fragment containing two attP sites, green fluorescent protein (gfp) as a first transgene, and an antibiotic resistance gene as a selection marker was self-ligated to generate non-replicative closed circular DNA (nrccDNA) for integration. nrccDNA was introduced into attB-inserted E. coli cells harboring the plasmid expressing Sre by electroporation. The expressed Sre catalyzed site-specific integration between one of the two attP sites on nrccDNA and the attB site on the E. coli chromosome. The integration frequency was affected by the chromosomal location of the target site. A second nrccDNA containing two attB sites, lacZ encoding the alpha fragment of -galactosidase as a transgene, and another antibiotic resistance gene was integrated into the residual attP site on the gfp-integrated E. coli chromosome via one of the two attB sites according to reiterating site-specific recombination. The integrants clearly exhibited -galactosidase activity and green fluorescence, suggesting the simultaneous expression of multiple recombinant proteins in E. coli. The results of the present study showed that a step-by-step integration procedure using nrccDNA achieved the chromosomal integration of multiple genes., WILEY-BLACKWELL
    JOURNAL OF BASIC MICROBIOLOGY, 2016年06月, [査読有り]
  • Inoculation with nitrous oxide (N2O)-reducing denitrifier strains simultaneously mitigates N2O emission from pasture soil and promotes growth of pasture plants
    Nan Gao; Weishou Shen; Hiroko Kakuta; Nobuhiro Tanaka; Toru Fujiwara; Tomoyasu Nishizawa; Noriko Takaya; Tadashi Nagamine; Kazuo Isobe; Shigeto Otsuka; Keishi Senoo, The aim of this study was to screen nitrous oxide (N2O)-reducing denitrifier strains showing both N2O mitigation and plant growth-promoting (PGP) effects in soil systems, and the effects of selected strains were monitored in soil and plant, analyzed, and comparatively evaluated. Forty denitrifier strains affiliated with Azospirillum and Herbaspirillum, previously isolated from three different paddy soils, were evaluated. Of these, 11 produced indole-3-acetic acid (>5 jig mL(-1)), 9 promoted the growth of red clover (Trifolium pratense L. var. Medium) or timothy (Phleum pratense L. var. Horizon) on agar plates, and 7 were inoculated into two different soils for cultivating red clover and timothy in a greenhouse. Compared with non-inoculated control, N2O flux from red clover soil and from timothy soil were significantly lower 8 and 14 days and 9 days onwards, respectively, after inoculation with these seven strains. Cumulative N2O emissions from red clover soil were significantly lowered through inoculation with these seven strains. The growth parameters, including plant height, leaf area, fresh weight or dry weight, of the two pasture plants were significantly greater in soils inoculated with most of these seven strains than in non inoculated soils. The uptake of C and N by the two pasture plants was significantly greater in soils inoculated with most of these seven strains than in non-inoculated soils. In conclusion, inoculating N2O reducing denitrifiers to pasture soil could mitigate N2O emissions and simultaneously promote the growth of pasture plants in a greenhouse. These strains will be invaluable microbiological resources for developing novel biofertilizers. (C) 2016 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
    SOIL BIOLOGY & BIOCHEMISTRY, 2016年06月, [査読有り]
  • Mycoavidus cysteinexigens gen. nov., sp nov., an endohyphal bacterium isolated from a soil isolate of the fungus Mortierella elongata
    Shoko Ohshima; Yoshinori Sato; Reiko Fujimura; Yusuke Takashima; Moriyuki Hamada; Tomoyasu Nishizawa; Kazuhiko Narisawa; Hiroyuki Ohta, An endohyphal bacterium (strain B1-EBT) living in association with the fungus Mortierella elongata FMR23-6 I-B1 was isolated from a fungal cell homogenate and studied for its taxonomic allocation. Cells were Gram-stain-negative, rod-shaped, non-spore-forming, non-motile, and negative for oxidase and catalase. Strain B1-EBT required cysteine for growth and grew at temperatures between 4 and 35 degrees C. A comparative analysis of 16S rRNA gene sequences revealed that strain B1-EBT forms a distinct clade in the family Burkholderiaceae, encompassing a group of endosymbionts associated with several soil isolates of M. elongata. The most closely related genus is 'Candidatus Glomeribacter gigasporarum', an endosymbiont of the arbuscular mycorrhizal fungus Gigaspora margarita. The major cellular fatty acids of strain B1-EBT were C-16 : 0, summed feature 3 (C-16 : (1)omega 7c and C-16 : (1)omega 6c) and summed feature 8 (C-18 : (1)omega 7c or C-18 : (1)omega 6c). Ubiquinone Q-8 was the only quinone detected. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, an unknown aminophospholipid and two unknown aminolipids. The DNA G+C content was 49.8 mol%. On the basis of phenotypic, chemotaxonomic, and phylogenetic characteristics, strain B1-EBT represents a novel genus and novel species in the family Burkholderiaceae, for which the name Mycoavidus cysteinexigens gen. nov., sp. nov. is proposed. The type strain is B1-EBT (=JCM 30646(T) =LMG 28693(T) =NBRC 110909(T))., SOC GENERAL MICROBIOLOGY
    INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY, 2016年05月, [査読有り]
  • Complete genome sequence of Streptomyces parvulus 2297, integrating sitespecifically with actinophage R4
    Tomoyasu Nishizawa; Takamasa Miura; Chizuko Harada; Yong Guo; Kazuhiko Narisawa; Hiroyuki Ohta; Hideo Takahashi; Makoto Shirai, Streptomyces parvulus 2297, which is a host for site-specific recombination according to actinophage R4, is derived from the type strain ATCC 12434. Species of S. parvulus are known as producers of polypeptide antibiotic actinomycins and have been considered for industrial applications. We herein report for the first time the complete genome sequence of S. parvulus 2297., American Society for Microbiology
    Genome Announcements, 2016年, [査読有り]
  • Complete genome sequence of the nonylphenol-degrading bacterium Sphingobium cloacae JCM 10874T
    Mina Ootsuka; Tomoyasu Nishizawa; Hiroyuki Ohta, Sphingobium cloacae JCM 10874T can degrade phenolic endocrine-disrupting chemicals, nonylphenol, and octylphenol. Here, we report the complete genome sequence of the JCM 10874T strain., American Society for Microbiology
    Genome Announcements, 2016年, [査読有り]
  • 土壌には未知の脱窒微生物が豊富に存在している
    磯部一夫; 魏魏; 西澤智康; 白鳥豊; 大塚重人; 妹尾啓史
    土と微生物, 2015年10月, [査読有り]
  • 土壌生成プロセスにおける微生物の役割
    太田寬行・西澤智康・藤村玲子, 日本土壌微生物学会
    土と微生物, 2015年10月, [招待有り]
  • Higher diversity and abundance of denitrifying microorganisms in environments than considered previously
    Wei Wei; Kazuo Isobe; Tomoyasu Nishizawa; Lin Zhu; Yutaka Shiratori; Nobuhito Ohte; Keisuke Koba; Shigeto Otsuka; Keishi Senoo, Denitrification is an important process in the global nitrogen cycle. The genes encoding NirK and NirS (nirK and nirS), which catalyze the reduction of nitrite to nitric oxide, have been used as marker genes to study the ecological behavior of denitrifiers in environments. However, conventional polymerase chain reaction (PCR) primers can only detect a limited range of the phylogenetically diverse nirK and nirS. Thus, we developed new PCR primers covering the diverse nirK and nirS. Clone library and qPCR analysis using the primers showed that nirK and nirS in terrestrial environments are more phylogenetically diverse and 2-6 times more abundant than those revealed with the conventional primers. RNA-and culture-based analyses using a cropland soil also suggested that microorganisms with previously unconsidered nirK or nirS are responsible for denitrification in the soil. PCR techniques still have a greater capacity for the deep analysis of target genes than PCR-independent methods including metagenome analysis, although efforts are needed to minimize the PCR biases. The methodology and the insights obtained here should allow us to achieve a more precise understanding of the ecological behavior of denitrifiers and facilitate more precise estimate of denitrification in environments., NATURE PUBLISHING GROUP
    ISME JOURNAL, 2015年09月, [査読有り]
  • Development of PCR primers targeting fungal nirK to study fungal denitrification in the environment
    Wei Wei; Kazuo Isobe; Yutaka Shiratori; Tomoyasu Nishizawa; Nobuhito Ohte; Yuta Ise; Shigeto Otsuka; Keishi Senoo, Fungal denitrification in soils is receiving considerable attention as one of the dominant N2O production processes. However, because of the lack of a methodology to detect fungal denitrification-related genes, the diversity and ecological behavior of denitrifying fungi in soil remains unknown. Thus, we designed a primer set to detect the fungal nitrite reductase gene (nirK) and validated its sensitivity and specificity. Through clone library analyses, we identified congruence between phylogenies of the 18S rRNA gene and nirK of denitrifying fungal isolates obtained from the surface-fertilized cropland soil and showed that fungi belonging to Eurotiales, Hypocreales, and Sordariales were primarily responsible for N2O emissions in the soil. (C) 2014 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
    SOIL BIOLOGY & BIOCHEMISTRY, 2015年02月, [査読有り]
  • Molecular analysis of the cyanobacterial community in gastric contents of egrets with symptoms of steatitis
    Tomoyasu Nishizawa; Yasuko Neagari; Takamasa Miura; Munehiko Asayama; Koichi Murata; Ken-Ichi Harada; Makoto Shirai, Many deaths of wild birds that have drunk water contaminated with hepatotoxic microcystin-producing cyanobacteria have been reported. A mass death of egrets and herons with steatitis were found at the agricultural reservoir occurring cyanobacterial waterblooms. This study aimed to verify a hypothesis that the egrets and herons which died in the reservoir drink microcystin-producing cyanobacteria and microcystin involves in the cause of death as well as the symptoms of steatitis. The cyanobacterial community in gastric contents of egrets and herons that died from steatitis was assessed using cyanobacterial 16S rRNA-based terminal-restriction fragment length polymorphism (T-RFLP) profiling and a cyanobacterial 16S rRNA-based clone library analysis. In addition, PCR amplification of the mcyB–C region and the mcyG gene, involved in microcystin biosynthesis, was examined. The cyanobacterial community in the gastric contents of two birds showed a simplistic composition. A comparison of cyanobacterial T-RFLP profiling and cloned sequences suggested that the genus Microcystis predominated in both samples of egrets died. Although we confirmed that two egrets which died in the reservoir have taken in cyanobacterial waterblooms containing the genus Microcystis, no mcy gene was detected in both samples according to the mcy gene-based PCR analysis. This study is the first to show the profiling and traceability of a cyanobacterial community in the gastric contents of wild birds by molecular analysis. Additionally, we consider causing symptoms of steatitis in the dead egrets., Bentham Science Publishers B.V.
    Open Microbiology Journal, 2015年, [査読有り]
  • Change in rhizosphere microbial community of Miscanthus condensatus, a pioneer plant on recent Miyake-jima volcanic deposit, during the vegetation development(The Joint Meeting of Japanese Environmental Microbiology-related Associations 2014)               
    Guo, Yong; Fujimura, Reiko; Sato, Yoshinori; Nishizawa, Tomoyasu; Kamijo, Takashi; Ohta, Hiroyuki, 日本土壌微生物学会
    土と微生物, 2014年10月
  • 微生物の遺伝子解析からゲノム解析、そしてゲノム情報活用へ
    西澤智康, 筆頭著者, 日本土壌微生物学会
    土と微生物, 2014年10月
  • Construction of a stepwise gene integration system by transient expression of actinophage R4 integrase in cyanobacterium Synechocystis sp PCC 6803
    Takamasa Miura; Akito Nishizawa; Tomoyasu Nishizawa; Munehiko Asayama; Hideo Takahashi; Makoto Shirai, The integrase of actinophage R4, which belongs to the large serine-recombinase family, catalyzes site-specific recombination between two distinct attachment site sequences of the phage (attP) and actinomycete Streptomyces parvulus 2297 chromosome (attB). We previously reported that R4 integrase (Sre) catalyzed site-specific recombination both in vivo and in vitro. In the present study, a Sre-based system was developed for the stepwise site-specific integration of multiple genes into the chromosome of cyanobacterium Synechocystis sp. PCC 6803 (hereafter PCC 6803). A transgene-integrated plasmid with two attP sites and a non-replicative sre-containing plasmid were co-introduced into attB-inserted PCC 6803 cells. The transiently expressed Sre catalyzed highly efficient site-specific integration between one of the two attP sites on the integration plasmid and the attB site on the chromosome of PCC 6803. A second transgene-integrated plasmid with an attB site was integrated into the residual attP site on the chromosome by repeating site-specific recombination. The transformation frequencies (%) of the first and second integrations were approximately 5.1 x 10(-5) and 8.2 x 10(-5), respectively. Furthermore, the expression of two transgenes was detected. This study is the first to apply the multiple gene site-specific integration system based on R4 integrase to cyanobacteria., SPRINGER HEIDELBERG
    MOLECULAR GENETICS AND GENOMICS, 2014年08月, [査読有り]
  • Inoculation with N-2-generating denitrifier strains mitigates N2O emission from agricultural soil fertilized with poultry manure
    Tomoyasu Nishizawa; Aihua Quan; Ayaaki Kai; Kanako Tago; Satoshi Ishii; Weishou Shen; Kazuo Isobe; Shigeto Otsuka; Keishi Senoo, Pelleted poultry manure is recommended for use with agricultural soil as a replacement for chemical fertilizers; however, application of the manure stimulates nitrous oxide (N2O) emission from the soil through denitrification. To mitigate the N2O emission caused by application of pelleted poultry manure, soil microcosms were set up; each microcosm was inoculated with one of the following N-2-generating denitrifier strains previously been isolated from paddy soil: Azoarcus, Dyella, Dechloromonas, Niastella, and Burkholderia. When pelleted poultry manure was incubated on its own, N2O was produced by denitrification. In contrast, N2O emission was significantly lowered when the manure was inoculated with most of the N-2-generating strains. In soil microcosms, N2O was emitted during incubation after application of the pelleted manure, while N2O flux was significantly lowered when the soil was inoculated with Azoarcus sp. KS11B, Niastella sp. KS31B, or Burkholderia sp. TSO47-3 on the 12th day of incubation. In addition, when pelleted manure was inoculated with the strains prior to application in the soil microcosms, the level of N2O emission was significantly lowered to ca. 40-60 % that from the non-inoculated control. Our study provides the prototype of a technique that uses microbial technology to mitigate N2O emission from agricultural soil fertilized with pelleted poultry manure., SPRINGER
    BIOLOGY AND FERTILITY OF SOILS, 2014年08月, [査読有り]
  • Plant growth promoting ability of Azoarcus sp. KH32C, a N2O-mitigating denitrifier isolated from rice paddy soil               
    Nishizawa; T.; T. Hakoyama; S. Uraguchi; H. Kakuta; K. Isobe; S. Otsuka; S. Sakuda; T. Fujiwara; K. Senoo, 筆頭著者, EAFES
    The 6th EAFES International Congress, 2014年04月
  • Root-associated microbial diversity of a pioneer grass, Miscanthus condensatus, on the recent volcanic deposits in the Island of Miyake, Japan               
    Guo; Y.; R. Fujimura; Y. Sato; T. Nishizawa; T. Kamijo; H. Ohta, EAFES
    The 6th EAFES International Congress, 2014年04月
  • N2O emission from cropland field soil through fungal denitrification after surface applications of organic fertilizer
    Wei Wei; Kazuo Isobe; Yutaka Shiratori; Tomoyasu Nishizawa; Nobuhito Ohte; Shigeto Otsuka; Keishi Senoo, Agricultural fields are one of the largest anthropogenic sources of atmospheric nitrous oxide (N2O). Fungi have been suggested to contribute substantially to N2O emission in terrestrial environments; however, the extent of the fungal contribution and the phylogenetic and physiologic nature of related fungal communities in agricultural fields are largely unknown. This study focused on the large N2O emission from cropland soil that occurs after granular organic fertilizers were applied to the surface. The granular organic fertilizers applied were evidently covered by fungal mycelia. An experiment using a soil microcosm was established to imitate the field observations. N2O emissions following surface organic fertilization were suppressed by 84 and 20% after the addition of cycloheximide (a fungal inhibitor) and streptomycin (a bacterial inhibitor), respectively, suggesting that fungi provide the main contribution to the observed N2O emission. The population density and community composition of fungi in the surface-fertilized and non-fertilized soils in the field were determined using colony counting, denaturing gradient gel electrophoresis and subsequent phylogenetic analyses. Thirty-four fungal strains were isolated from the soils, and their N2O producing activities were analyzed. Fungal population density in the surface-fertilized soil (2.6 x 10(6) CFU/g) was much higher than that in the non-fertilized soil (1.0 x 105 CFU/g). In addition, the fungal community compositions of the soils differed. Actinomucor elegans, Bionectria ochroleuca, Fusarium avenaceum, Fusarium equiseti, Fusarium oxysporum, Fusarium solani and Nectria sp. dominated the surface-fertilized soil, and their activity in producing N2O was confirmed. These results suggested that N2O emission after the surface application of granular organic fertilizers in the cropland field mainly resulted from fungal denitrification. (C) 2013 Elsevier Ltd. All rights reserved., PERGAMON-ELSEVIER SCIENCE LTD
    SOIL BIOLOGY & BIOCHEMISTRY, 2014年02月, [査読有り]
  • Draft genome sequence of the betaproteobacterial endosymbiont associated with the fungus Mortierella elongata FMR23-6
    Reiko Fujimura; Ayumu Nishimura; Shoko Ohshima; Yoshinori Sato; Tomoyasu Nishizawa; Kenshiro Oshima; Masahira Hattori; Kazuhiko Narisawa; Hiroyuki Ohta, The fungus Mortierella elongata FMR23-6 harbors an endobacterium inside its mycelium. Attempts to isolate the endobacterium from the fungus were not yet successful, but a highly purified bacterial fraction was prepared. Here, we report the draft genome sequence of the endobacterium., American Society for Microbiology
    Genome Announcements, 2014年, [査読有り]
  • Characterization of lysis of the multicellular cyanobacterium Limnothrix/Pseudanabaena sp. strain ABRG5-3
    Kitazaki; C.; S. Numano; A. Takanezawa; T. Nishizawa; M. Shirai; M. Asayama, The cyanobacterium semi-filamentous multicellular strain ABRG5-3 undergoes cell lysis as a unique feature that occurs due to growth condition changes from normal cultivation with shaking to static cultivation without shaking in liquid culture (Nishizawa et al., 2010). Microscopic observation and energy dispersive X-ray spectrometer (EDX) analysis have revealed that lysis is involved in the accumulation of polyphosphate compounds and the disintegration of thylakoid membranes in cells. Static cultivation, dark or red light exposure, and temperature (22 to 42 degrees C) conditions were found to be effective factors for the induction of lysis. Moreover, stress induced by salts, osmotic pressure with sucrose, and the depletion of nitrogen or phosphate in cultures also induced ABRG5-3 cell lysis. Based on these results, we discuss lysis and its utilization in the biotechnology industry., Taylor & Francis
    Biosci. Biotechnol. Biochem., 2013年12月, [査読有り]
  • Taxonomic composition of denitrifying bacterial isolates is different among three rice paddy field soils in Japan
    Tomoyasu Nishizawa; Yusuke Uei; Kanako Tago; Kazuo Isobe; Shigeto Otsuka; Keishi Senoo, Denitrification is one of the important nitrogen transformation processes in rice (Oryza sativa L.) paddy soil. We have performed both culture-dependent and -independent studies to investigate the key players in denitrification in rice paddy soil. Our previous works suggested the possibility that community composition of denitrifying populations is different among soils. To confirm this possibility, in the present study, denitrifying bacteria were isolated from rice paddy field soils (Kumamoto and Tokyo) in Japan by the functional single-cell isolation method, and examined for their taxonomic position. Combined with our previously isolated strains from Niigata paddy field soil, our results clearly indicated that the taxonomic composition of the denitrifying bacterial community is different at the genus level among three soils. A significant difference in mean potential denitrification activity of the isolates at the genus level was also found. Soil and/or other environmental factors could shape the community structure of denitrifiers in rice paddy soil., TAYLOR & FRANCIS LTD
    SOIL SCIENCE AND PLANT NUTRITION, 2013年06月, [査読有り]
  • Detection of Anammox Activity and 16S rRNA Genes in Ravine Paddy Field Soil
    Yoshinori Sato; Hiroyuki Ohta; Takao Yamagishi; Yong Guo; Tomoyasu Nishizawa; M. Habibur Rahman; Hisao Kuroda; Task Kato; Masanori Saito; Ikuo Yoshinaga; Kazuyuki Inubushi; Yuichi Suwa, An anammox assay involving a N-15 tracer and gas chromatography-mass spectrometry revealed that the potential anammox activity accounted for 1 to 5% of total N-2 production in a ravine paddy field, Japan. Among four 4-cm-deep layers, the top layer showed the highest activity. Clone libraries showed that the DNA in the top layer contained sequences related to those of Candidatus 'Brocadia fulgida', Ca. 'B. anammoxidans', and Ca. 'Kuenenia stuttgartiensis'. These results suggest that a specific population of anammox bacteria was present in paddy soils, although a small part of dinitrogen gas was emitted from the soil via anammox., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2012年09月, [査読有り]
  • Complete Genome Sequence of Leptospirillum ferrooxidans Strain C2-3, Isolated from a Fresh Volcanic Ash Deposit on the Island of Miyake, Japan
    Reiko Fujimura; Yoshinori Sato; Tomoyasu Nishizawa; Kenshiro Oshima; Seok-Won Kim; Masahira Hattori; Takashi Kamijo; Hiroyuki Ohta, A diazotrophic, acidophilic, iron-oxidizing bacterium, Leptospirillum ferrooxidans, known to be difficult to cultivate, was isolated from a fresh volcanic ash deposit on the island of Miyake, Japan. Here, we report the complete genome sequence of a cultured strain, C2-3., AMER SOC MICROBIOLOGY
    JOURNAL OF BACTERIOLOGY, 2012年08月, [査読有り]
  • Heterologous expression of a plant ReIA-SpoT homologue results in increased stress tolerance in Saccharomyces cerevisiae by accumulation of the bacterial alarmone ppGpp
    Kozo Ochi; Tomoyasu Nishizawa; Takashi Inaoka; Akiyo Yamada; Kohsuke Hashimoto; Takeshi Hosaka; Susumu Okamoto; Yoshihiro Ozeki, The bacterial alarmone ppGpp is present only in bacteria and the chloroplasts of plants, but not in mammalian cells or eukaryotic micro-organisms such as yeasts and fungi. The importance of the ppGpp signalling system in eukaryotes has therefore been largely overlooked. Here, we demonstrated that heterologous expression of a reIA-spoT homologue (Sj-RSH) isolated from the halophilic plant Suaeda japonica in the yeast Saccharomyces cerevisiae results in accumulation of ppGpp, accompanied by enhancement of tolerance against various stress stimuli, such as osmotic stress, ethanol, hydrogen peroxide, high temperature and freezing. Unlike bacterial ppGpp accumulation, ppGpp was accumulated in the early growth phase but not in the late growth phase. Moreover, nutritional downshift resulted in a decrease in ppGpp level, suggesting that the observed Sj-RSH activity to synthesize ppGpp is not starvation-dependent, contrary to our expectations based on bacteria. Accumulated ppGpp was found to be present solely in the cytosolic fraction and not in the mitochondrial fraction, perhaps reflecting the ribosome-independent ppGpp synthesis in S. cerevisiae cells. Unlike bacterial inosine monophosphate (IMP) dehydrogenases, the IMP dehydrogenase of S. cerevisiae was insensitive to ppGpp. Microarray analysis showed that ppGpp accumulation gave rise to marked changes in gene expression, with both upregulation and downregulation, including changes in mitochondrial gene expression. The most prominent upregulation (38-fold) was detected in the hypothetical gene YBR072C-A of unknown function, followed by many other known stress-responsive genes. S. cerevisiae may provide new opportunities to uncover and analyse the ppGpp signalling system in eukaryotic cells., SOC GENERAL MICROBIOLOGY
    MICROBIOLOGY-SGM, 2012年08月, [査読有り]
  • Complete Genome Sequence of the Denitrifying and N2O-Reducing Bacterium Azoarcus sp Strain KH32C
    Tomoyasu Nishizawa; Kanako Tago; Kenshiro Oshima; Masahira Hattori; Satoshi Ishii; Shigeto Otsuka; Keishi Senoo, We report the finished and annotated genome sequence of a denitrifying and N2O-reducing betaproteobacterium, Azoarcus sp. strain KH32C. The genome is composed of one chromosome and one megaplasmid and contains genes for plant-microbe interactions and the gene clusters for aromatic-compound degradations., AMER SOC MICROBIOLOGY
    JOURNAL OF BACTERIOLOGY, 2012年03月, [査読有り]
  • Analysis of Early Bacterial Communities on Volcanic Deposits on the Island of Miyake (Miyake-jima), Japan: a 6-year Study at a Fixed Site
    Reiko Fujimura; Yoshinori Sato; Tomoyasu Nishizawa; Kenji Nanba; Kenshiro Oshima; Masahira Hattori; Takashi Kamijo; Hiroyuki Ohta, Microbial colonization on new terrestrial substrates represents the initiation of new soil ecosystem formation. In this study, we analyzed early bacterial communities growing on volcanic ash deposits derived from the 2000 Mount Oyama eruption on the island of Miyake (Miyake-jima), Japan. A site was established in an unvegetated area near the summit and investigated over a 6-year period from 2003 to 2009. Collected samples were acidic (pH 3.0-3.6), did not utilize any organic substrates in ECO microplate assays (Biolog), and harbored around 10(6) cells (g dry weight)(-1) of autotrophic Fe(II) oxidizers by most-probable-number (MPN) counts. Acidithiobacillus ferrooxidans, Acidithiobacillus ferrivorans, and the Leptospirillum groups I, II and III were found to be abundant in the deposits by clone library analysis of bacterial 16S rRNA genes. The numerical dominance of Acidithiobacillus ferrooxidans was also supported by analysis of the gene coding for the large subunit of the form I ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). Comparing the 16S rRNA gene clone libraries from samples differing in age, shifts in Fe(II)-oxidizing populations seemed to occur with deposit aging. The detection of known 16S rRNA gene sequences from Fe(III)-reducing acidophiles promoted us to propose the acidity-driven iron cycle for the early microbial ecosystem on the deposit., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2012年03月, [査読有り]
  • Advantages of functional single-cell isolation method over standard agar plate dilution method as a tool for studying denitrifying bacteria in rice paddy soil
    Tomoyasu Nishizawa; Kanako Tago; Yusuke Uei; Satoshi Ishii; Kazuo Isobe; Shigeto Otsuka; Keishi Senoo, We recently established a method for isolating functional single cells from environmental samples using a micromanipulator (Functional single-cell (FSC) isolation), and applied it to the study of denitrifying bacteria in rice paddy soil (Ashida et al. 2010. Appl Microbiol Biotechnol 85:1211-1217). To further examine the advantages and possible disadvantages of the FSC method, we isolated denitrifying bacteria from the same rice paddy soil sample using both FSC and standard agar plate dilution (APD) methods and compared in this study. The proportion of denitrifying bacteria in the total isolates was more than 6-fold larger with FSC isolation (57.1%) compared with the APD method (9.2%). Denitrifying bacteria belonging to Alphaproteobacteria and Bacilli were commonly isolated using both methods, whereas those belonging to Betaproteobacteria, which had been found to be active in the denitrification-inductive paddy soil, were isolated only with the FSC method. On the other hand, Actinobacteria were only isolated using the APD method. The mean potential denitrification activity of the FSC isolates was higher than that of the APD isolates. Overall, FSC isolation was confirmed to be an excellent method for studying denitrifying bacteria compared with the standard agar plate dilution method., BIOMED CENTRAL LTD
    AMB EXPRESS, 2012年, [査読有り]
  • Complete genome sequence of the denitrifying and N2O-reducing bacterium Pseudogulbenkiania sp. strain NH8B
    Ishii; S.; K. Tago; T. Nishizawa; K. Oshima; M. Hattori; K. Senoo, Pseudogulbenkiania sp. strain NH8B is a Neisseriales bacterium isolated from an agricultural field. This strain has strong denitrification and N2O reduction activities. Here, we report the finished and annotated genome sequence of this organism., Am Soc Microbiol
    J. Bacteriol., 2011年10月, [査読有り]
  • In vivo and in vitro characterization of site-specific recombination of actinophage R4 integrase
    Miura; T.; Y. Hosaka; Y.-Z. Yang; T. Nishizawa; M. Asayama; H. Takahashi; and M. Shirai, The site-specific integrase of actinophage R4 belongs to the serine recombinase family. During the lysogenization process, it catalyzes site-specific recombination between the phage genome and the chromosome of Streptomyces parvulus 2297. An in vivo assay using Escherichia coli cells revealed that the minimum lengths of the recombination sites attB and attP are 50-bp and 49-bp, respectively, for efficient intramolecular recombination. The in vitro assay using overproduced R4 integrases as a hexahistidine (His(6))-glutathione-S-transferase (GST)-R4 integrase fusion protein, showed that the purified protein preparation retains the site-specific recombination activity which catalyzes the site-specific recombination between affP and attB in the intermolecular reaction. It also revealed that the inverted repeat within attP is essential for efficient in vitro intermolecular recombination. In addition, a gel shift assay showed that His(6)-GST-R4 integrase bound to the 50-bp attB and 49-bp attP specifically. Moreover, based on a detailed comparison analysis of amino acid sequences of serine integrases, we found the DNA binding region that is conserved in the serine recombinase containing the large C-terminal domain. Based on the results presented on this report, attachment sites needed in vitro and in vivo for site-specific recombination by the R4 integrase have been defined more precisely. This knowledge is useful for developing new genetic manipulation tools in the future., Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
    J. Gen. Appl. Microbiol., 2011年04月, [査読有り]
  • Phylogenetic and Functional Diversity of Denitrifying Bacteria Isolated from Various Rice Paddy and Rice-Soybean Rotation Fields
    Kanako Tago; Satoshi Ishii; Tomoyasu Nishizawa; Shigeto Otsuka; Keishi Senoo, Denitrifiers can produce and consume nitrous oxide (N(2)O). While little N(2)O is emitted from rice paddy soil, the same soil produces N(2)O when the land is drained and used for upland crop cultivation. In this study, we collected soils from two types of fields each at three locations in Japan; one type of field had been used for continuous cultivation of rice and the other for rotational cultivation of rice and soybean. Active denitrifiers were isolated from these soils using a functional single-cell isolation method, and their taxonomy and denitrifying properties were examined. A total of 110 denitrifiers were obtained, including those previously detected by a culture-independent analysis. Strains belonging to the genus Pseudogulbenkiania were dominant at all locations, suggesting that Pseudogulbenkiania denitrifiers are ubiquitous in various rice paddy soils. Potential denitrifying activity was similar among the strains, regardless of the differences in taxonomic position and soil of origin. However, relative amounts of N(2) in denitrification end products varied among strains isolated from different locations. Our results also showed that crop rotation had minimal impact on the functional diversity of the denitrifying strains. These results indicate that soil and other environmental factors, excluding cropping systems, could select for N(2)-producing denitrifiers., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2011年03月, [査読有り]
  • Limnobacter litoralis sp. nov., a thiosulfate-oxidizing, heterotrophic bacterium isolated from a volcanic deposit, and emended description of the genus Limnobacter
    Hongsheng Lu; Yoshinori Sato; Reiko Fujimura; Tomoyasu Nishizawa; Takashi Kamijo; Hiroyuki Ohta, A Gram-negative, aerobic, heterotrophic bacterium, designated KP1-19T, was isolated from a 22-year-old volcanic deposit at a site lacking vegetation on the island of Miyake, Japan. Strain KP1-19Twas able to use thiosulfate (optimum concentration 10 mM) as an additional energy source. 16S rRNA gene sequence analysis indicated that strain KP1-19Twas closely related toLimnobacter thiooxidansCS-K2Twithin the classBetaproteobacteria(97.7 % 16S rRNA gene sequence similarity). The cellular fatty acid profile was characteristic of the genusLimnobacter: the major fatty acids (>5 %) were C16 : 0, C16 : 1ω7cand C18 : 1ω7cand minor amounts of C10 : 03-OH were also found. DNA–DNA relatedness between strain KP1-19TandL. thiooxidansLMG 19593Twas 18 %. Therefore, strain KP1-19Trepresents a novel species, for which the nameLimnobacter litoralissp. nov. is proposed. The type strain is KP1-19T(=LMG 24869T=NBRC 105857T=CIP 109929T)., Microbiology Society
    International Journal of Systematic and Evolutionary Microbiology, 2011年02月, [査読有り]
  • Characterization of the locus of genes encoding enzymes producing heptadepsipeptide micropeptin in the unicellular cyanobacterium Microcystis
    Tomoyasu Nishizawa; Akiko Ueda; Tomoyo Nakano; Akito Nishizawa; Takamasa Miura; Munehiko Asayama; Kiyonaga Fujii; Ken-ichi Harada; Makoto Shirai, The gene cluster involved in producing the cyclic heptadepsipeptide micropeptin was cloned from the genome of the unicellular cyanobacterium Microcystis aeruginosa K-139. Sequencing revealed four genes encoding non-ribosomal peptide synthetases (NRPSs) that are highly similar to the gene cluster involved in cyanopeptolins biosynthesis. According to predictions based on the non-ribosomal consensus code, the order of the mcnABCE NPRS modules was well consistent with that of the biosynthetic assembly of cyclic peptides. The biochemical analysis of a McnB(K-139) adenylation domain and the knock-out of mcnC in a micropeptin-producing strain, M. viridis S-70, revealed that the mcn gene clusters were responsible for the production of heptadepsipeptide micropeptins. A detailed comparison of nucleotide sequences also showed that the regions between the mcnC and mcnE genes of M. aeruginosa K-139 retained short stretches of DNA homologous to halogenase genes involved in the synthesis of halogenated cyclic peptides of the cyanopeptolin class including anabaenopeptilides. This suggests that the mcn clusters of M. aeruginosa K-139 have lost the halogenase genes during evolution. Finally, a comparative bioinformatics analysis of the congenial gene cluster for depsipetide biosynthesis suggested the diversification and propagation of the NRPS genes in cyanobacteria., OXFORD UNIV PRESS
    JOURNAL OF BIOCHEMISTRY, 2011年, [査読有り]
  • Detection of Betaproteobacteria inside the Mycelium of the Fungus Mortierella elongata
    Yoshinori Sato; Kazuhiko Narisawa; Kazuto Tsuruta; Masafumi Umezu; Tomoyasu Nishizawa; Kenji Tanaka; Kaoru Yamaguchi; Masakazu Komatsuzaki; Hiroyuki Ohta, Microscopic and molecular analyses showed the presence of endobacteria inside the mycelia of four out of twelve nitrous oxide (N(2)O)-producing fungal isolates identified as Mortierella elongata. The 16S rRNA gene was successfully amplified with DNA extracted directly from the endobacterium-containing fungal strains and all sequences were related to that of Candidatus Glomeribacter gigasporarum in the family Burkholderiaceae. Bacterial endotoxin was detected in the endobacterium-positive fungal strains but only trace levels were found in endobacterium-negative strains. No significant relationship was found between the fungal N(2)O-producing activity and the presence of endobacteria., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2010年12月, [査読有り]
  • 細菌の生態学的種を考える
    西澤智康・佐藤嘉則・藤村玲子・太田寛行, 筆頭著者, 16S rRNA 遺伝子解析が導入される前の時代,土壌細菌研究者の多くは,分離菌株の分類学的位置づけがどのような生態的意味をもつかについて一度は考え悩むときがあったと思う.そのような時代の最初の頃に,栗原は「ecological species(生態学的種)の概念の確立」を説いた(1965年).2000年代に入り,遺伝子変異の観点から細菌のecotype(エコタイプ)や細菌種の見直しが盛んに議論されている.ここでは,まず栗原の考察を読み解き,Cohanが提唱する細菌の「エコタイプ」について解説するとともに,著者らが扱ってきた初成土壌(三宅島2000年噴火火山灰堆積物)に住みつく細菌の分析結果を紹介して,細菌の生態学的種について考える話題を提供する., 日本農芸化学会
    化学と生物, 2010年10月
  • Molecular Characterization of Fungal Communities in Non-Tilled, Cover-Cropped Upland Rice Field Soils
    Tomoyasu Nishizawa; Zhaorigetu; Masakazu Komatsuzaki; Yoshinori Sato; Nobuhiro Kaneko; Hiroyuki Ohta, This study aimed to characterize soil fungal communities in upland rice fields managed with tillage/non-tillage and winter cover-cropping (hairy vetch and cereal rye) practices, using PCR-based molecular methods. The study plots were maintained as upland fields for 5 years and the soils sampled in the second and fifth years were analyzed using T-RFLP (terminal restriction fragment length polymorphism) profiling and clone libraries with the internal transcribed spacer (ITS) region and domain 1 (D1) of the fungal large-subunit (fLSU) rRNA (D1(fLSU)) as the target DNA sequence. From the 2nd-year-sample, 372 cloned sequences of fungal ITS-D1(fLSU) were obtained and clustered into 80 non-redundant fungal OTUs (operational taxonomic units) in 4 fungal phyla. The T-RFLP profiling was performed with the 2nd- and 5th-year-samples and the major T-RFs (terminal restriction fragments) were identified using a theoretical fragment analysis of the ITS-D1(fLSU) clones. These molecular analyses showed that the fungal community was influenced more strongly by the cover-cropping than tillage practices. Moreover, the non-tilled, cover-cropped soil was characterized by a predominance of Cryptococcus sp. in the phylum Basidiomycota. We provided a genetic database of the fungal ITS-D1(fLSU)s in the differently managed soils of upland rice fields., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2010年09月, [査読有り]
  • Isolation and Molecular Characterization of a Multicellular Cyanobacterium, Limnothrix/Pseudanabaena sp Strain ABRG5-3
    Tomoyasu Nishizawa; Tomoyo Hanami; Eriko Hirano; Takamasa Miura; Yuko Watanabe; Akira Takanezawa; Masakazu Komatsuzaki; Hiroyuki Ohta; Makoto Shirai; Munehiko Asayama, A cyanobacterium, semi-filamentous multicellular strain ABRG5-3, was isolated and its unique nature was characterized. This axenic strain formal colonies and was motile on an agarose plate. The 16S rRNA gene of ABRG5-3 exhibited similarities to those of the Limnothrix and Pseudanabaena strains, which are known as filamentous and nonheterocystous cyanobacteria. Peaks in absorbance for the accumulation of chlorophyll a, phycocyanin, and phycoerythrin were observed in the cell extract. Natural separation of the pigments occurred in the supernatant of the autolysed cells. The cell lysis was promoted by osmotic shocks and lysozyme treatments. Chlorophyll a and total DNA were abundantly recovered from the cells. Analysis of the restriction-modification system for genomic DNA revealed novel diversity. Moreover, we made a successful attempt to create antibiotic-resistant strains by conjugation with a foreign plasmid, which indicates that strain ABRG5-3 is transformable., TAYLOR & FRANCIS LTD
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY, 2010年09月, [査読有り]
  • 末端制限断片(T-RFs)プロファイル情報に基づく土壌微生物群集構造解析
    西澤智康・小松﨑将一・金子信博・太田寛行, 筆頭著者, 土壌環境中に存在する微生物の多様性や土壌環境変化への微生物群集の応答を調べるため,リアルタイム定量PCRアッセイと末端制限断片長多型解析(T-RFLP)法を併用した手法を確立した。この解析手法から,標的遺伝子領域に基づく微生物群の末端制限断片(T-RFs)サイズとピーク高(相対値)の情報が得られる。T-RFLPプロファイリングの実測情報とクローン解析から得られた遺伝子配列のin silico解析によるT-RFsプロファイル情報がほぼ一致することから,本法が精度の高い解析技術であることを示した。また,検出されたT-FRsプロファイル情報をもとに多次元尺度構成法分析で微生物群集の類似性とその動態を表す方法,そしてT-RFsの相対的存在量の頻度分布順位図から微生物の多様性を示す方法を紹介した。さらに,T-RFsプロファイル情報をもとに土壌微生物群集を推定するバイオインフォマテッィクスの利用方法を示した。今後のデータベースの充実により,定量PCR-T-KELP法が土壌微生物群集モニタリングに大いに役立つことを期待している。, 日本土壌微生物学会
    土と微生物, 2010年04月
  • Correlation between variation in McyB1 module and biosynthesis of microcystin isoforms
    Nishizawa, A; T. Nishizawa; M. Asayama; M. Hasegawa; K. Harada; M. Shirai, Res Insti Meijo Univ
    J. Res. Insti. Meijo Univ., 2009年12月, [査読有り]
  • Genetic analysis of the microcystin biosynthesis gene cluster in Microcystis strains from four bodies of eutrophic water in Japan
    Noguchi; T.; A. Shinohara; A. Nishizawa; M. Asayama; T. Nakano; M. Hasegawa; K. Harada; T. Nishizawa; M. Shirai, The highly conserved organization of microcystin biosynthesis (mcy) gene clusters, which includes nonribosomal peptide synthetase (NRPS) genes, polyketide synthase (PKS) genes, and fused NRPS-PKS genes, has been characterized in the genus Microcystis. In this study, a total of 135 cyanobacterial strains from four different geographical locations in Japan were isolated. Fourteen mcy-possessing (mcy(+)) strains were identified according to PCR amplification between two genes from domestic mcy(+) strains and the mcy gene's organization was classified into five types. Phylogenetic relationships of the 16S-23S internal transcribed spacer region indicated that the five types of mcy gene cluster structure classified into two groups of the genus Microcystis. HPLC of the isolated mcy(+) strain containing a partial deletion of mcyI (Delta mcyI) revealed that microcystin production disappeared. A transcriptional analysis of the Delta mcyI-strain and an assay of recombinant McyI dehydrogenase activity showed that McyI is responsible for microcystin biosynthesis. Based on patterns of the PCR amplicons and analyses of nucleotide sequences in the mcy gene cluster of Microcystis, we confirmed the presence of inserts at three specific loci, between mcyA and mcyD, and downstream of mcyC and mcyI. Our study is the first investigation of the mcy gene cluster structure in the genus Microcystis from environmental samples., Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
    J. Gen. Appl. Microbiol., 2009年04月, [査読有り]
  • Nitrogenase Activity (Acetylene Reduction) of an Iron-Oxidizing Leptospirillum Strain Cultured as a Pioneer Microbe from a Recent Volcanic Deposit on Miyake-Jima, Japan
    Yoshinori Sato; Ken Hosokawa; Reiko Fujimura; Tomoyasu Nishizawa; Takashi Kamijo; Hiroyuki Ohta, The genus Leptospirillum is known to dominate acid mine drainage and bioleaching systems. In this paper, we describe the isolation of iron-oxidizing bacteria closely related to Leptospirillum ferrooxidans from an acidic volcanic ash deposit on the island of Miyake (Miyake-jima), Japan. We further show the nitrogenase activity (acetylene reduction) for one (strain C2-1) of the isolates. The deposit harbored 1.2 x 10(8) total direct count (g dry weight)(-1) and 7.1 x 10(5) (most-probable-number, MPN) (g dry weight)(-1) of iron-oxidizer. A ferrous iron-limited, aerobic chemostat culture using Leptospirillum HH medium (pH 1.8) was performed to select and isolate the Leptospirillum group. Nine isolates were regarded as pure cultures based on uniform colony morphology on Fe(2+)-containing silica gel plates and absence of growth on 100-fold diluted nutrient broth plates. Six strains examined further shared 99.9-100% identity in 16S rRNA gene sequence with each other. Homology-based searches showed that all of the strains belonged to the Leptospirillum ferrooxidans clade. Strain C2-1 grown in ammonium sulfate-free Leptospirillum HH medium (pH 1.8) showed an initial rate of acetylene reduction of 58 mu mol h(-1) (g cell carbon)(-1)., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2009年, [査読有り]
  • Archaeal Diversity of Upland Rice Field Soils Assessed by the Terminal Restriction Fragment Length Polymorphism Method Combined with Real Time Quantitative-PCR and a Clone Library Analysis
    Tomoyasu Nishizawa; Masakazu Komatsuzaki; Nobuhiro Kaneko; Hiroyuki Ohta, The PCR amplification-based analysis of microbial diversity is subject to potential problems. In this study, to minimize the bias toward a 1: 1 ratio in multitemplate PCR, a real-time PCR assay was carried out using a quenching fluorescence dye primer and amplification efficiency was monitored. Then terminal-restriction fragment length polymorphism (T-RFLP) profiling was performed using the PCR product with minimized PCR bias. This method was applied to an analysis of the diversity of the archacal community in an upland rice field under different tillage systems and winter cover cropping. Terminal restriction fragments (T-RFs) of PCR-amplified archacal 16S rRNA genes were assigned to the gene sequences recovered from the same soil by using an archaeal 16S rRNA gene clone library. Our results indicated that soil archaeal members were not influenced but the relative abundance of archaeal species particularly those belonging to Crenarchaeota which changed between the tillage and non-tillage treatments., JAPANESE SOC MICROBIAL ECOLOGY, DEPT BIORESOURCE SCIENCE
    MICROBES AND ENVIRONMENTS, 2008年, [査読有り]
  • Diversity within the microcystin biosynthetic gene clusters among the genus Microcystis
    Nishizawa; T.; A. Nishizawa; M. Asayama; K. Harada; M. Shirai, 筆頭著者, The principle organization of microcystin biosynthesis (mcy) gene clusters is characterized in three genera among the microcystin-producing cyanobacteria. To examine the conservation of the mcy gene clusters among the genus Microcystis, internal non-coding regions of the cluster in 21 strains including M. aeruginosa, M. viridis, and M. wesenbergii, were amplified by PCR using specific primer sets and sequenced. PCR-based analysis revealed a completely conserved organization of the bidirectional cluster structure, mcyABC and mcyDEFGHIJ, among all toxic and some microcystin-negative strains. Furthermore, all mcy gene clusters were flanked by a gene with homology to dnaN adjacent to mcyJ and by umal with no-homology to any known genes at the 3'-end of mcyC. Transposase homolog genes were observed in a non-coding region between dnaN and mcyJ in three rnicrocystin-producing Microcystis strains. Sequence analysis of a region adjacent to umal in mcy-negative strains revealed two types of gene constitution, dnaN-umal and the hypothetical protein gene-umal. PCR-based analyses can be used to assess the identification of microcystin-producer strains in Microcystis spp., Jap Soc Microb Eco & Jap Soc Soil Microbiol
    Microbes Environ., 2007年12月, [査読有り]
  • Cloning and characterization of a new hetero-gene cluster of nonribosomal synthetase and polyketide synthase from the cyanobacterium Microcystis aeruginosa K-139
    Nishizawa; A.; A.B. Arshad; T. Nishizawa; M. Asayama; K. Fujii; T. Nakano; K. Harada; M. Shirai, Two nonribosomal peptide synthetase genes responsible for the biosynthesis of microcystin and micropeptin in Microcystis aeruginosa K-139 have been identified. A new nonribosomal peptide synthetase gene, psm3, was identified in M. aeruginosa K-139. The gene is a cluster extending 30 kb and comprising 13 bidirectionally transcribed open reading frames arranged in two putative operons. psm3 encodes four adenylation proteins, one polyketide synthase, and several unique proteins, especially Psm3L consisting of halogenase, acyl-CoA binding protein-like protein, and acyl carrier protein. Alignment of the binding pocket of the adenylation domain and an ATIR-PPi exchange analysis using a recombinant protein with the adenylation domain of Psm3B showed that Psm3G and Psm3B activate aspartic acid and tyrosine, respectively. Although disruption of psm3 did not reveal the product produced by Psm3, we identified microviridin B and aeruginosin K139 in the cells of M. aeruginosa K-139. The above-mentioned results indicated that M. aeruginosa possesses at least five nonribosomal peptide synthetase gene clusters., Applied Microbiology, Molecular and Cellular Biosciences Research Foundation
    J. Gen. Appl. Microbiol., 2007年04月, [査読有り]
  • トキシンをつくるシアノバクテリア
    西澤智康・白井 誠, 筆頭著者, エヌ・ティー・エス
    生物の科学 遺伝, 2006年11月
  • Physiological analysis of the stringent response elicited in an extreme thermophilic bacterium, Thermus thermophilus
    Koji Kasai; Tomoyasu Nishizawa; Kosaku Takahashi; Takeshi Hosaka; Hiroyuki Aoki; Kozo Ochi, Guanosine tetraphosphate (ppGpp) is a key mediator of stringent control, an adaptive response of bacteria to amino acid starvation, and has thus been termed a bacterial alarmone. Previous X-ray crystallographic analysis has provided a structural basis for the transcriptional regulation of RNA polymerase activity by ppGpp in the thermophillic bacterium Thermus thermophilus. Here we investigated the physiological basis of the stringent response by comparing the changes in intracellular ppGpp levels and the rate of RNA synthesis in stringent (rel(+); wild type) and relaxed (relA and relC; mutant) strains of T. thermophilus. We found that in wild-type T. thermophilus, as in other bacteria, serine hydroxamate, an amino acid analogue that inhibits tRNA(ser) aminoacylation, elicited a stringent response characterized in part by intracellular accumulation of ppGpp and that this response was completely blocked in a relA-null mutant and partially blocked in a relC mutant harboring a mutation in the ribosomal protein L11. Subsequent in vitro assays using ribosomes isolated from wild-type and relA and relC mutant strains confirmed that (p)ppGpp is synthesized by ribosomes and that mutation of RelA or L11 blocks that activity. This conclusion was further confirmed in vitro by demonstrating that thiostrepton or tetracycline inhibits (p)ppGpp synthesis. In an in vitro system, (p)ppGpp acted by inhibiting RNA polymerase-catalyzed 23S/5S rRNA gene transcription but at a concentration much higher than that of the observed intracellular ppGpp pool size. On the other hand, changes in the rRNA gene promoter activity tightly correlated with changes in the GTP but not ATP concentration. Also, (p)ppGpp exerted a potent inhibitory effect on IMP dehydrogenase activity. The present data thus complement the earlier structural analysis by providing physiological evidence that T. thermophilus does produce ppGpp in response to amino acid starvation in a ribosome-dependent (i.e., RelA-dependent) manner. However, it appears that in T. thermophilus, rRNA promoter activity is controlled directly by the GTP pool size, which is modulated by ppGpp via inhibition of IMP dehydrogenase activity. Thus, unlike the case of Escherichia coli, ppGpp may not inhibit T. thermophilus RNA polymerase activity directly in vivo, as recently proposed for Bacillus subtilis rRNA transcription (L. Krasny and R. L. Gourse, EMBO J. 23:4473-4483, 2004)., AMER SOC MICROBIOLOGY
    JOURNAL OF BACTERIOLOGY, 2006年10月, [査読有り]
  • Enzymatic assembly of the bis-indole core of rebeccamycin
    T Nishizawa; S Gruschow; DHE Jayamaha; C Nishizawa-Harada; DH Sherman, AMER CHEMICAL SOC
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2006年01月, [査読有り]
  • Molecular analysis of the rebeccamycin L-amino acid oxidase from Lechevalieria aerocolonigenes ATCC 39243
    T Nishizawa; CC Aldrich; DH Sherman, Rebeccamycin, a member of the tryptophan-derived indolocarbazole family, is produced by Lechevalieria aerocolonigenes ATCC 39243. The biosynthetic pathway that specifies biosynthesis of this important metabolite is comprised of 11 genes spanning 18 kb of DNA. A presumed early enzyme involved in elaboration of the rebeccamycin aglycone is encoded by rebO, located at the left-hand region of the reb gene cluster. The deduced protein product, RebO (51.9 kDa), is an L-amino acid oxidase (L-AAO) that has 27% identity to an L-AAO from Scomber japonicus (animal, mackerel) and is a member of the family of FAD-dependent oxidase enzymes. In order to study the biochemical properties of this key enzyme, the rebO gene was overexpressed and purified from Escherichia coli. Biochemical characterization showed that RebO is dimeric, with a molecular mass of approximately 101 kDa. Further analysis revealed that the enzyme contains a noncovalently bound FAD cofactor and is reoxidized at the expense of molecular oxygen by producing one molecule of hydrogen peroxide. Based on kinetic studies, RebO shows significant preference for 7-chloro-L-tryptophan, suggesting its likely role as the natural early pathway substrate. Furthermore, the native RebO enzyme has evident, albeit limited, flexibility as shown by bioconversion studies with unnatural substrates. This work provides the first analysis of a structural enzyme involved in construction of this important class of indolocarbazole natural products., AMER SOC MICROBIOLOGY
    JOURNAL OF BACTERIOLOGY, 2005年03月, [査読有り]
  • DNA cloning of peptide synthetase from cyanobacterium Aphanizomenon flos-aquae
    Masaaki Kodama; Jeen Hee Lee; Shigeharu Kinoshita; Shigeru Sato; Takehiko Ogata; Tomoyasu Nishizawa; Makoto Shirai; Yuzuru Shimizu; Shugo Watabe, SPRINGER TOKYO
    FISHERIES SCIENCE, 2002年
  • Cyclic heptapeptide microcystin bisosynthesis requires the glutamate racemase gene
    Nishizawa; T.; M. Asayama; M. Shirai, 筆頭著者, It was demonstrated previously that the operon consisting of the nonribosomal peptide synthetase (NRPS) gene coupled with the polyketide synthase (PKS) gene involved in cyclic heptapeptide microcystin synthesis includes two different D-amino acid synthetase genes, an epimerization domain at the 3' end of module 2, and the racemase gene mcyF, To determine the role of mcyF in microcystin synthesis, gene-disruption and complementation analyses were carried out. Insertional mutagenesis in the mcyF gene, generated by homologous recombination, abolished only microcystin synthesis, but did not influence cell growth, Furthermore, McyF supported D-Glu-independent growth of a strain of Escherichia coli defective in D-Glu synthesis, It is concluded that mcyF is the glutamic acid racemase gene involved in the synthesis of D-Glu residues in the microcystin molecule. This is the first report of the racemase in prokaryotic NRPS., Microbiology Society
    Microbiology, 2001年05月, [査読有り]
  • 解明されたアオコ毒素合成系:ポリケチド合成モジュールが融合した非リボソーム型ペプチド合成系
    西澤智康・白井 誠, 筆頭著者, 日本農芸化学会
    化学と生物, 2000年11月
  • 有毒ラン藻が産生する第二次代謝産物の生合成に関する研究(1) : 有毒および無毒ペプチドの構造と合成酵素遺伝子
    Fujii, K; T. Nishizawa; M. Asayama; K. Sivonenn; M. Shirai; K. Harada, The occurrence of water blooms of cyanobacteria is a wild-wide problem in eutrophic lakes. In some cases, such blooms of cyanobacteria produce microcystins, which are known as the potent hepatotoxin and liver tumor promoter. Microcystins are cyclic heptapeptides and are non-ribosomally synthesized. For the regulation of the production of microcystins by toxic cyanobacteria, we have investigated their biosynthesis. Initially, we carried out the detection, isolation and structural determination of non-toxic peptides produced together with microcystins by toxic cyanobacteria. As shown in Table 1, the isolated non-toxic peptides were classified into several groups on the basis of their structures. The results suggested that the production of these non-toxic peptides is closely related to that of microcystins. In the course of our investigations, Shirai et al. recently identified whole microcystin synthetase genes in the toxic cyanobacterium, Microcystis aeruginosa K-139, which produces 3-desmethyl and 3,7-didesmethyl microcystin-LR (Fig. 1, 2(a)). Furthermore, the synthetic genes of a peptide other than microcystins were also isolated from the same strain (Fig. 2(b)). In this study, we carried out the isolation and structural determination of the corresponding peptide to the synthetic genes isolated. As the result, we isolated a non-toxic peptide designated as micropeptin K139 (1) together with two microcystins from M. aeruginosa K-139. Micropeptin K139 (1) is a cyclic depsipeptide composed of seven amino acids, L-Ile x2, L-MeTyr, L-Ahp, L-Arg, L-Thr, L-Asp, and a fatty acid, HA, and belongs to a group of non-toxic peptides (Fig. 1). The sequence of the constituent segments in 1 and its structure were determined by 2D-NMR techniques, and the advanced Marfey's method was used to determine their absolute configurations. The findings about the structure of micropeptin K139 (1) and the isolated peptide synthetase genes other than those of microcystins indicated that these synthetic genes are for a nontoxic peptide, 1. Therefore, the result suggested that non-toxic peptides are also non-ribosomally synthesized as well as microcystins. The investigation of the genetic relationship between microcystins and the co-producing peptides is in progress., 天然有機化合物討論会
    第42回天然有機化合物討論会, 2000年10月, [査読有り]
  • Polyketide synthase gene coupled to the peptide synthetase module involved in the biosynthesis of the cyclic heptapeptide microcystin
    Nishizawa; T.; A. Ueda; M. Asayama; K. Fujii; K. Harada; K. Ochi; M. Shirai, 筆頭著者, The peptide synthetase gene operon, which consists of mcyA, mcyB, anti mcyC, for the activation and incorporation of the five amino acid constituents of microcystin has been identified [T. Nishizawa et al. (1999) J. Biochem. 126, 52-529]. By sequencing an additional 34 kb of DNA from microcystin-producing Microcystis aeruginosa K-139, we identified the residual microcystin synthetase gene operon, which consists of mcyD, mcyE, mcyF,and mcyG, in the opposite orientation to the mcyABC operon. McyD consisted of two polyketide synthase modules, and McyE contained a polyketide synthase module at the N-terminus and a peptide synthetase module at the C-terminus. McyF was found to exhibit similarity to amino acid racemase, McyG consisted of a peptide synthetase module at the N-terminus and a polyketide synthase at the C-terminus, The microcystin synthetase gene cluster was conserved in another microcystin-producing strain, Microcystis sp, S-70, which produces Microcystin-LR, -RR, and -YR. Insertional mutagenesis of mcyA, mcyD, or mcyE in Microcystis sp, S-70 abolished microcystin production. In conclusion, the mcyDEFG operon is presumed to be responsible for 3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda) biosynthesis, and the incorporation of Adda and glutamic acid into the microcystin molecule., Oxford University Press
    J. Biochem., 2000年05月, [査読有り]
  • Genetic analysis of the peptide synthetase genes for a cyclic heptapeptide microcystin in Microcystis spp.
    T Nishizawa; M Asayama; K Fujii; K Harada; M Shirai, Peptide-synthetase-encoding DNA fragments were isolated by a PCR-based approach from the chromosome of Microcystis aeruginosa K-139, which produces cyclic heptapeptides, 7-desmethylmicrocystin-LR and 3,7-didesmethylmicrocystin-LR. Three open reading frames (mcyA, mcyB, mcyC) encoding microcystin synthetases were identified in the gene cluster. Sequence analysis indicated that McyA (315 kDa) consists of two modules with an N-methylation domain attached to the first and an epimerization domain attached to the second; McyB (242 kDa) has two modules, and McyC (147 kDa) contains one module with a putative C-terminal thioesterase domain. Conserved amino acid sequence motifs for ATP binding, ATP hydrolysis, adenylate formation, and 4'-phosphspantetheine attachment were identified by sequence comparison with authentic peptide synthetase. Insertion mutations in mcyA, generated by homologous recombination, abolished the production of both microcystins in ill. aeruginosa K-139, Primer extension analysis demonstrated light-dependent mcy expression. Southern hybridization and partial DNA sequencing analyses of six microcystin-producing and two non-producing Microcystis strains suggested that the microcystin-producing strains contain the mcy gene and the non-producing strains can be divided into two groups, those possessing no mcy genes and those with mcy genes., JAPANESE BIOCHEMICAL SOC
    JOURNAL OF BIOCHEMISTRY, 1999年09月, [査読有り]

MISC

書籍等出版物

  • Investigating Endobacteria that Thrive Within Mucoromycota. In: Martin, F., Uroz, S. (eds) Microbial Environmental Genomics (MEG). Methods in Molecular Biology, vol 2605. Humana, New York, NY.
    Desirò; A.; Y. Takashima; G. Bonito; T. Nishizawa; K. Narisawa; P. Bonfante, 共著
    Humana, New York, NY, 2022年12月, [査読有り]
    9781071628706
  • 難培養微生物研究の最前線Ⅲ―微生物の生き様に迫り課題解決へ―《普及版》               
    太田寛行・佐藤嘉則・西澤智康, 共著
    シーエムシー出版, 2022年04月
    9784781316314
  • 実践土壌学シリーズ3 土壌生化学               
    境 雅夫・西澤智康, 分担執筆
    朝倉書店, 2019年02月
    9784254435733
  • 実践土壌学シリーズ1 土壌微生物学               
    西澤智康, 分担執筆
    朝倉書店, 2018年08月
    9784254435719
  • 土のひみつ 食料・環境・生命               
    西澤智康, 分担執筆
    朝倉書店, 2015年09月
    9784254400236
  • 難培養微生物研究の最前線Ⅲ―微生物の生き様に迫り課題解決へ―               
    太田寛行,佐藤嘉則,西澤智康, 共著
    シーエムシー出版, 2015年08月
    9784781310817
  • 土壌微生物実験法 第3版(日本土壌微生物学会編)               
    西澤智康, 分担執筆
    養賢堂, 2013年06月
    9784842505169
  • Photosynthesis: Theory and Applications in Energy, Biotechnology and Nanotechnology               
    Nishizawa, T; M. Asayama; M. Shirai, 分担執筆
    Nova Science Publishers, Inc., 2009年05月, [査読有り]
    9781606927199
  • Adaptive Gene Regulations-from Microorganisms to Organelles               
    Nishizawa, T; A. Nishizawa; M. Shirai, 分担執筆
    Research Signpost, 2008年12月, [査読有り]
    9788130802664

講演・口頭発表等

  • 霞ケ浦(北浦)の湖底堆積物における窒素循環系微生物群集構造解析               
    正田岳志; 中里亮治; 西澤智康
    公開シンポジウム 霞ヶ浦流域研究2024(GLEC水圏環境フィールドステーション・オンライン), 2024年03月
    202403
  • 霞ヶ浦(北浦)および河川流域における薬剤耐性細菌の動態解析               
    早川美久; 中里亮治; 西澤智康
    公開シンポジウム 霞ヶ浦流域研究2024(GLEC水圏環境フィールドステーション・オンライン), 2024年03月
    202403
  • カバークロップと微生物資材を利用した有機水稲栽培における水田土壌管理と水稲収量との関係               
    加来嵩時・武藤光輝・高嶋尚哉・菅井 純・遠山佳甫・迫田 翠・浅木直美・伊沢 剛・西澤智康・小松﨑将一
    第24回 日本有機農業学会(大阪)大会(摂南大学 枚方キャンパス), 2023年12月
    202312, 202312
  • 三内丸山遺跡「子供の墓」土遺構に発生した外生菌根菌子実体の同定とその分布               
    長尾理伶・轟丈瑠・山田紀代美・佐々木淑美・石崎武志・佐藤嘉則・西澤智康
    日本文化財科学会第40回記念大会(奈良、奈良県立なら歴史芸術文化村), 2023年10月
    202310, 202310
  • 耕起から不耕起への転換が畑地土壌の窒素動態に及ぼす影響               
    遠山佳甫; 淺木直美; 迫田 翠; 郭 永; 西澤智康
    日本土壌肥料学会2023年度愛媛大会(愛媛大学 城北キャンパス), 2023年09月
    202309, 202309
  • 霞ヶ浦(北浦)湖底堆積物における薬剤耐性細菌の推定               
    早川 美久; 郭 永; 迫田 翠; 正田 岳志; 中里 亮治; 西澤 智康
    日本土壌微生物学会2023年度大会(千葉大学 松戸キャンパス), 2023年06月, 日本土壌微生物学会
    202306, 202306
  • Effect of no-tillage on SOM accumulation and biological properties of Andosols from a long-term experiment in Japan               
    Aduhene-Chinbuah; J; S. Sughihara; M. Komatsuzaki; T. Nishizawa; H. Tanaka
    8th International Symposium on Soil Organic Matter (SOM 2022, Seoul, Korea), 2022年06月, Korean Society of Soil Science and Fertilizer (KSSSF)
    202206, 202206
  • 農学的な切り口で温室効果ガスの発生と消費を考えてみる,ー微生物が、どのように気候変動に影響を与えているのか?ー               
    西澤智康
    第7回 茨城大学カーボンニュートラルオープンセミナー(オンライン開催), 2021年11月, 茨城大学「2050年カーボンニュートラル」連続講演会タスクフォース, [招待有り]
    202111, 202111
  • シンポジウム:真菌と生存空間を共有する微生物から見た真菌学,糸状菌細胞に内生する細菌の微生物相互作用               
    郭 永・高島 勇介・西澤 智康
    第94回 日本細菌学会総会(オンライン開催), 2021年03月, [招待有り]
    202103, 202103
  • シンポジウム:三宅島噴火から20年,2000年噴火火山灰中の微生物群集の構造と動態変化               
    太田寛行・西澤智康
    日本生態学会 第68回大会(岡山大会・オンライン), 2021年03月, [招待有り]
    202103, 202103
  • 土壌団粒構造と土壌プロセス2 畑地土壌団粒における微生物群集の構造・動態変化 農地土壌管理が微生物性に与えるインパクト               
    西澤智康; 太田寬行
    日本土壌肥料学会2019年度大会(静岡、静岡大学), 2019年09月, 日本土壌肥料学会
  • 土壌団粒構造と土壌プロセス2,畑地土壌団粒における微生物群集の構造・動態変化 農地土壌管理が微生物性に与えるインパクト               
    西澤智康・太田寬行
    日本土壌肥料学会2019年度大会(静岡、静岡大学), 2019年09月, 日本土壌肥料学会
  • 糸状菌ー内生細菌の微生物間相互作用現象の解明
    西澤智康
    第13回助成研究報告会(大阪、千里ライフサイエンスセンター), 2019年06月, 公益財団法人発酵研究所, [招待有り]
  • 霞ヶ浦周辺環境における薬剤耐性菌の分布
    矢用もも・平野明則・松田祐輝・上原研人・今井達也・島袋真・黒田久雄・太田寛行・西澤智康
    第17回世界湖沼会議(いばらき霞ヶ浦2018)分科会(つくば国際会議場), 2018年10月
  • 福島県駒止湿原開拓開墾地における土壌環境条件と植生回復
    坂上伸生・郭永・高島勇介・西澤智康・成澤才彦・渡邊眞紀子
    第17回世界湖沼会議(いばらき霞ヶ浦2018)分科会(つくば国際会議場), 2018年10月
  • 『農法の違いを微生物性解析で「見える化」』
    西澤 智康
    第三回土壌団粒勉強会(仙台、東北大学), 2017年09月
  • 土壌層位形成過程や土壌団粒構造の微生物群集構造解析               
    西澤 智康; 太田 寬行
    環境微生物系学会合同大会2017(仙台、東北大学), 2017年08月
  • 石人山古墳装飾石棺表面の微生物群集構造解析               
    佐藤嘉則・西澤智康・小沼奈那美・犬塚将英・森井順之・木川りか・朽津信明
    文化財保存修復学会第39回大会(石川、金沢歌劇座), 2017年07月
  • 土壌生成プロセスにおける微生物の役割               
    太田寬行・西澤智康
    日本土壌微生物学会 2015 年度大会(つくば):学会シンポジウム「国際土壌年-土と微生物を考える」, 2015年05月
  • Plant growth promoting ability of Azoarcus sp. KH32C, a potent N2O-mitigating denitrifier               
    Tomoyasu Nishizawa; Ayaaki Kai; Hiroko Kakuta; Kazuo Isobe; Shigeto Otsuka; Tsuneo Hakoyama; Shimpei Uraguchi; Toru Fujiwara; Keishi Senoo
    18th International Congress on Nitrogen Fixation, 2013年10月
  • 霞ヶ浦に発生したアオコの微生物群集構造解析               
    *西澤 智康,二渡 弘貴,朝山 宗彦,原田 健一,白井 誠
    日本藻類学会第 34 回大会(つくば 2010)(茨城,筑波大学), 2010年03月
  • 有毒アオコ群集の発生機構と動態解析               
    西澤 智康
    第3回公開シンポジウム「霞ヶ浦流域再生プロジェクト」, 2009年10月, 茨城大学農学部
  • 末端制限断片(T-RFs)データによる畑地土壌微生物多様性解析:複数の解析手法を用いた評価方法の検討               
    西澤 智康・石井 真英・小松崎 将一・金子 信博・太田 寛行
    日本土壌肥料学会2009年度京都大会(京都大学), 2009年09月, 日本土壌肥料学会 第3 部門
  • T-RFLPプロファイルによる畑地土壌微生物群集構造の解析               
    西澤智康; 石井真英; 梅津昌史; 昭日格図; 小松崎将一; 金子信博; 太田寛行
    日本土壌微生物学会2009年度大会(九州、福岡), 2009年06月
  • Microcystis株におけるミクロシスチン合成遺伝子構成の保存性               
    西澤智康、西澤明人、野口貴彦、原田健一、朝山宗彦、白井誠
    第22回 日本微生物生態学会(東京、東京大学), 2006年10月

所属学協会

  • 2014年 - 現在, アメリカ微生物学会
  • 2009年 - 現在, 日本土壌肥料学会
  • 2009年 - 現在, 日本ゲノム微生物学会
  • 2008年 - 現在, 日本土壌微生物学会
  • 2006年06月 - 現在, 日本微生物生態学会

共同研究・競争的資金等の研究課題

  • 噴火年代が異なる火山島の三宅島と御蔵島における植生と土壌の長期火山遷移               
    基盤研究(B)
    2023年04月 - 2026年03月
  • 三内丸山遺跡の土遺構の保存に関する総合的研究
    基盤研究(B)
    東北芸術工科大学
    2022年04月 - 2026年03月
  • 霞ヶ浦流域生態系における薬剤耐性菌の分布および動態の解明               
    河川基金助成事業
    2023年04月 - 2024年03月
  • エンドファイト-バクテリア共生系がイチゴの花芽形成を促進する               
    挑戦的研究(萌芽)
    2022年06月 - 2024年03月
  • 農地由来の一酸化二窒素ガス消去技術の開発               
    Research Booster
    2021年10月 - 2023年03月
  • 〔主要な業績〕鍾乳洞における照明植生を軽減する光環境に関する実験的研究               
    基盤研究(C)
    2019年04月 - 2023年03月
  • 〔主要な業績〕内生細菌が腐生性Mortierella属菌に共生能を付与するメカニズムの解明               
    挑戦的研究(萌芽)
    2020年08月 - 2022年03月
  • 低メタン性をもたらすイネ-土壌ー微生物系の包括的キャラクタリゼーション               
    基盤研究(B)
    2019年04月 - 2022年03月
  • 三宅島2000年巨大噴火後の20年間の生態系回復過程               
    基盤研究(B)
    2019年04月 - 2022年03月
  • 緑肥導入体系における土壌微生物および小動物の動態と作物生産性               
    基盤研究(B)
    2018年04月 - 2021年03月
  • 内生細菌を操ることで腐生菌であるMortierella属菌を共生菌に変える!               
    挑戦的研究(萌芽)
    2018年07月 - 2020年03月
  • 内生細菌共生維持機構を利用して微生物に潜在機能を付与する技術の開発               
    基盤研究(C)一般
    2017年04月 - 2020年03月
  • 植物-エンドファイト-バクテリア共生系による新たな生物学的窒素固定技術の確立               
    基盤研究(B)一般
    2017年04月 - 2020年03月
  • 冷温帯における森林皆伐地の植生回復と土壌生成               
    基盤研究(C)一般
    2017年04月 - 2020年03月
  • 糸状菌-内生細菌の微生物間相互作用現象の解明               
    平成29年度(2017年度)大型研究助成
    2017年04月 - 2019年03月
  • 三宅島火山環境における土壌生成過程の微生物生態学的解析               
    基盤研究(B)一般
    2016年04月 - 2019年03月
  • 植物-土壌脱窒細菌間相互作用を担う新奇シグナル物質の同定               
    一般部門
    2017年05月 - 2018年04月
  • 環境制御による古墳に繁茂する緑色の軽減法に関する研究               
    基盤研究(C)一般
    2015年04月 - 2018年03月
  • エンドファイト-内生バクテリア共生系利用による植物への空中窒素固定能の付与               
    萌芽研究
    2015年04月 - 2017年03月
  • 不耕起栽培畑地土壌の物質循環系メタゲノム解析               
    基盤研究(B)特設
    2014年09月 - 2017年03月