慶應義塾研究者情報データベース

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• 『 小惑星べヌーの砂に生命を構成する「糖」が存在 』
  
  掲載誌：
  　Nature Geoscience
  
  タイトル：
  　Bio-essential sugars in samples from asteroid Bennu.
  
  論文サイト：
  　https://doi.org/10.1038/s41561-025-01838-6
  
  プレス詳細：
  　https://www.jamstec.go.jp/j/about/press_release/20251203/
  
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  『小惑星リュウグウの水に満ちた化学進化の源流と水質変成の証拠』
  
  掲載誌：
  Nature Communications
  
  タイトル：
  Primordial aqueous alteration recorded in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu.
  
  論文サイト：
  https://doi.org/10.1038/s41467-024-49237-6
  
  プレス詳細：
  https://www.jamstec.go.jp/j/about/press_release/20240710/

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• Abundant ammonia and nitrogen-rich soluble organic matter in samples from asteroid (101955) Bennu

  Glavin D.P., Dworkin J.P., Alexander C.M.O.D., Aponte J.C., Baczynski A.A., Barnes J.J., Bechtel H.A., Berger E.L., Burton A.S., Caselli P., Chung A.H., Clemett S.J., Cody G.D., Dominguez G., Elsila J.E., Farnsworth K.K., Foustoukos D.I., Freeman K.H., Furukawa Y., Gainsforth Z., Graham H.V., Grassi T., Giuliano B.M., Hamilton V.E., Haenecour P., Heck P.R., Hofmann A.E., House C.H., Huang Y., Kaplan H.H., Keller L.P., Kim B., Koga T., Liss M., McLain H.L., Marcus M.A., Matney M., McCoy T.J., McIntosh O.M., Mojarro A., Naraoka H., Nguyen A.N., Nuevo M., Nuth J.A., Oba Y., Parker E.T., Peretyazhko T.S., Sandford S.A., Santos E., Schmitt-Kopplin P., Seguin F., Simkus D.N., Shahid A., Takano Y., Thomas-Keprta K.L., Tripathi H., Weiss G., Zheng Y., Lunning N.G., Righter K., Connolly H.C., Lauretta D.S.

  Nature Astronomy 9 （ 2 ） 199 - 210 2025年02月

  ISSN  2397-3366

  　概要を見る

  Organic matter in meteorites reveals clues about early Solar System chemistry and the origin of molecules important to life, but terrestrial exposure complicates interpretation. Samples returned from the B-type asteroid Bennu by the Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer mission enabled us to study pristine carbonaceous astromaterial without uncontrolled exposure to Earth’s biosphere. Here we show that Bennu samples are volatile rich, with more carbon, nitrogen and ammonia than samples from asteroid Ryugu and most meteorites. Nitrogen-15 isotopic enrichments indicate that ammonia and other N-containing soluble molecules formed in a cold molecular cloud or the outer protoplanetary disk. We detected amino acids (including 14 of the 20 used in terrestrial biology), amines, formaldehyde, carboxylic acids, polycyclic aromatic hydrocarbons and N-heterocycles (including all five nucleobases found in DNA and RNA), along with ~10,000 N-bearing chemical species. All chiral non-protein amino acids were racemic or nearly so, implying that terrestrial life’s left-handed chirality may not be due to bias in prebiotic molecules delivered by impacts. The relative abundances of amino acids and other soluble organics suggest formation and alteration by low-temperature reactions, possibly in NH<inf>3</inf>-rich fluids. Bennu’s parent asteroid developed in or accreted ices from a reservoir in the outer Solar System where ammonia ice was stable.

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• Bio-essential sugars in samples from asteroid Bennu

  Furukawa Y., Sunami S., Takano Y., Koga T., Hirakawa Y., Oba Y., Naraoka H., Saigusa D., Yoshikawa T., Tanaka S., Glavin D.P., Dworkin J.P., Connolly H.C., Lauretta D.S.

  Nature Geoscience 2025年

  ISSN  17520894

  　概要を見る

  Deliveries of organic molecules from space, such as those found in carbonaceous meteorites, have long been hypothesized as a source of the inventory of the first life on Earth. This hypothesis is strengthened by detections of two of life’s fundamental building blocks—nucleobases and protein-building amino acids—in pristine samples returned by spacecraft from the carbonaceous asteroids Bennu and Ryugu. However, life also requires sugars, which cannot be searched for in Ryugu samples due to limited available mass, and their presence in some meteorites is equivocal owing to terrestrial exposure. Here we analyse an extract from a sample of asteroid (101955) Bennu collected by the OSIRIS-REx spacecraft and identify several bio-essential sugars, including ribose (RNA sugar) and glucose (metabolism substrate). These sugars complete the inventory of ingredients crucial to life. Their distribution is consistent with that in the condensation products of formaldehyde solution. Given that Bennu contains formaldehyde and originates from an ancient parent asteroid that underwent long-term alteration by aqueous fluids, we postulate that the detected sugars formed in the parent asteroid from brines containing formaldehyde. This indicates that material with all three components necessary to life could have been dispersed to prebiotic Earth and other inner planets.

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• Primordial aqueous alteration recorded in water-soluble organic molecules from the carbonaceous asteroid (162173) Ryugu

  Takano, Y., Naraoka, H., Dworkin, J.P., Koga, T., Sasaki, K., Sato, H., Oba, Y., Ogawa, N.O., Yoshimura, T., Hamase, K., Ohkouchi, N., Parker, E.T., Aponte, J.C., Glavin, D.P., Furukawa, Y., Aoki, J., Kano, K., Nomura, S.-i.M., Orthous-Daunay, F.-R., Schmitt-Kopplin, P., Yurimoto, H., Nakamura, T., Noguchi, T., Okazaki, R., Yabuta, H., Sakamoto, K., Yada, T., Nishimura, M., Nakato, A., Miyazaki, A., Yogata, K., Abe, M., Okada, T., Usui, T., Yoshikawa, M., Saiki, T., Tanaka, S., Terui, F., Nakazawa, S., Watanabe, S.-i., Tsuda, Y., Tachibana, S.

  Nature Communications （Nature Publishing Group）  15   5708 2024年07月

  研究論文（学術雑誌）, 共著, 筆頭著者, 責任著者, 査読有り

  • Access to Document (DOI)
  • Access to Document (DOI)

• Polycyclic aromatic hydrocarbons in samples of Ryugu formed in the interstellar medium

  Zeichner S.S., Aponte J.C., Bhattacharjee S., Dong G., Hofmann A.E., Dworkin J.P., Glavin D.P., Elsila J.E., Graham H.V., Naraoka H., Takano Y., Tachibana S., Karp A.T., Grice K., Holman A.I., Freeman K.H., Yurimoto H., Nakamura T., Noguchi T., Okazaki R., Yabuta H., Sakamoto K., Yada T., Nishimura M., Nakato A., Miyazaki A., Yogata K., Abe M., Okada T., Usui T., Yoshikawa M., Saiki T., Tanaka S., Terui F., Nakazawa S., Watanabe S.I., Tsuda Y., Hamase K., Fukushima K., Aoki D., Hashiguchi M., Mita H., Chikaraishi Y., Ohkouchi N., Ogawa N.O., Sakai S., Parker E.T., McLain H.L., Orthous-Daunay F.R., Vuitton V., Wolters C., Schmitt-Kopplin P., Hertkorn N., Thissen R., Ruf A., Isa J., Oba Y., Koga T., Yoshimura T., Araoka D., Sugahara H., Furusho A., Furukawa Y., Aoki J., Kano K., Nomura S.I.M., Sasaki K., Sato H., Yoshikawa T., Tanaka S., Morita M., Onose M., Kabashima F., Fujishima K., Yamazaki T., Kimura Y., Eiler J.M.

  Science （Science）  382 （ 6677 ） 1411 - 1416 2023年12月

  ISSN  00368075

  　概要を見る

  Polycyclic aromatic hydrocarbons (PAHs) contain ≲20% of the carbon in the interstellar medium. They are potentially produced in circumstellar environments (at temperatures ≳1000 kelvin), by reactions within cold (~10 kelvin) interstellar clouds, or by processing of carbon-rich dust grains. We report isotopic properties of PAHs extracted from samples of the asteroid Ryugu and the meteorite Murchison. The doubly-13C substituted compositions (D2×13C values) of the PAHs naphthalene, fluoranthene, and pyrene are 9 to 51% higher than values expected for a stochastic distribution of isotopes. The D2×13C values are higher than expected if the PAHs formed in a circumstellar environment, but consistent with formation in the interstellar medium. By contrast, the PAHs phenanthrene and anthracene in Ryugu samples have D2×13C values consistent with formation by higher-temperature reactions.

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• Uracil in the carbonaceous asteroid (162173) Ryugu

  Oba Y., Koga T., Takano Y., Ogawa N.O., Ohkouchi N., Sasaki K., Sato H., Glavin D.P., Dworkin J.P., Naraoka H., Tachibana S., Yurimoto H., Nakamura T., Noguchi T., Okazaki R., Yabuta H., Sakamoto K., Yada T., Nishimura M., Nakato A., Miyazaki A., Yogata K., Abe M., Okada T., Usui T., Yoshikawa M., Saiki T., Tanaka S., Terui F., Nakazawa S., Watanabe S.i., Tsuda Y.

  Nature Communications （Nature Communications）  14 （ 1 ）  2023年12月

  　概要を見る

  The pristine sample from the near-Earth carbonaceous asteroid (162173) Ryugu collected by the Hayabusa2 spacecraft enabled us to analyze the pristine extraterrestrial material without uncontrolled exposure to the Earth’s atmosphere and biosphere. The initial analysis team for the soluble organic matter reported the detection of wide variety of organic molecules including racemic amino acids in the Ryugu samples. Here we report the detection of uracil, one of the four nucleobases in ribonucleic acid, in aqueous extracts from Ryugu samples. In addition, nicotinic acid (niacin, a B3 vitamer), its derivatives, and imidazoles were detected in search for nitrogen heterocyclic molecules. The observed difference in the concentration of uracil between A0106 and C0107 may be related to the possible differences in the degree of alteration induced by energetic particles such as ultraviolet photons and cosmic rays. The present study strongly suggests that such molecules of prebiotic interest commonly formed in carbonaceous asteroids including Ryugu and were delivered to the early Earth.

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