Phylogeny and metabolism of microorganisms that grow better with D-amino acids

• Project/Area Number: 26506012
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: 宇宙生命学
• Research Institution: Hiroshima University
• Principal Investigator: Naganuma Takeshi 広島大学, 生物圏科学研究科, 教授 (70263738)
• Project Period (FY): 2014-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000); Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000); Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000); Fiscal Year 2016: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2015: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2014: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
• Keywords: Dアミノ酸 / 微生物 / ラオウルテラ・オルニチノリティカ / 遺伝子発現 / Dアミノ酸脱水素酵素 / ラセマーゼ / 大腸菌 / 細胞席合成 / Raoultella / R. ornithinolytica / Pseudomonas aeruginosa / Dグルタミン酸 / 定量PCR / Dアミノ酸酸化酵素 / グルタミン酸ラセマーゼ / L－アラニン：D－グルタミン酸リガーゼ / Dアミノ酸オキシダーゼ / キラリティ / アミノ酸 / 翻訳語修飾 / 宇宙生命

Outline of Final Research Achievements

A microorganism that grows better with D-glutamate as a sole organic nutrient was isolated from environment, against the general view of life primarily and mainly depending on L-amino acids, and was affiliated with Raoultella ornithinolytica. During the D-glutamate-based cultures of the isolated environmental strain and the standard strain of the species obtained from a culture collection, enhanced gene expressions of the enzyme D-amino acid dehydrogenase (DAD) were observed particularly in the late log-phase of their growth stages. The gene of the enzyme racemase, which had been expected to be most enhanced, was not enhanced. As possible metabolic advantages of the DAD enzyme, one-step production of useful α-keto acids from D-glutamate and, compared with the other relevantly involved enzymes, a wider range of oxidants availability and non-generation of harmful H2O2 are considered

Academic Significance and Societal Importance of the Research Achievements

Dアミノ酸でよりよく生育する生物は、他の研究グループが深海底から発見したDバリン資化菌が世界初の論文（2016）であり、本研究計画時（2013）に発見したDアミノ酸資化菌を本研究により詳細に研究した論文（2018）が世界2例目である。Dバリン資化菌は主にゲノム解析が行われたのに対し、本研究では「Dアミノ酸でよりよく生育」する際の遺伝子発現の定量を行い、それまで想定されていたラセマーゼ経由ではなく、Dアミノ酸脱水素酵素を経由する代謝系の重要性を指摘した点に学術的意義がある。これにより、近年になって芽生えてきたDアミノ酸バイオテクノロジーとその利用に基礎的な知見をもたらした点に社会的意義がある。

Research Products

• [Journal Article] Enhanced Bacterial Growth and Gene Expression of D-Amino Acid Dehydrogenase With D-Glutamate as the Sole Carbon Source (2018)
  • Author(s): Naganuma Takeshi、Iinuma Yoshiakira、Nishiwaki Hitomi、Murase Ryota、Masaki Kazuo、Nakai Ryosuke
  • Journal Title: Frontiers in Microbiology Volume: 9 Pages: 2555-2568
  • DOI: 10.3389/fmicb.2018.02097
  • Peer Reviewed / Open Access
• [Presentation] Corroborative study on “allo-biology” in hypothetical extraterrestrial biospheres (2017)
  • Author(s): 長沼 毅
  • Organizer: 第5回 宇宙における生命ワークショップ
  • Place of Presentation: 一橋大学一橋講堂（東京都千代田区）
  • Year and Date: 2017-03-06
  • Invited
• [Presentation] Dアミノ酸でよりよく生育する微生物： アンチキラル生物を探して (2014)
  • Author(s): 西脇 瞳, 村瀬 良太, 長沼 毅
  • Organizer: 環境微生物系学会合同大会 2014
  • Place of Presentation: 静岡県浜松市
  • Year and Date: 2014-10-21 – 2014-10-24
• [Presentation] Microorganisms that prefer D-amino acids: toward a search for anti-chiral organisms (2014)
  • Author(s): Nishiwaki Hitomi , Murase Ryota and Naganuma Takeshi
  • Organizer: The Second ISSOL - The International Astrobiology Society and Bioastronomy
  • Place of Presentation: 奈良県奈良市
  • Year and Date: 2014-07-06 – 2014-07-11