TAKANO Yoshinori

写真a

Affiliation

Graduate School of Media and Governance ( Shonan Fujisawa )

Position

Project Associate Professor (Non-tenured)

Related Websites

External Links

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  • Press Release:
    『Evidence of aqueous alteration and ongoing molecular evolution in the asteroid Ryugu: abiotic precursor of amino acids and nucleobases』

    Journal:
    Nature Communications

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

    Journal site:
    https://doi.org/10.1038/s41467-024-49237-6

    Press site:
    https://www.jamstec.go.jp/e/about/press_release/20240710/

    Institute for Advanced Biosciences (IAB), Keio University:
    https://www.iab.keio.ac.jp/news-events/2024/07111755.html

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Papers 【 Display / hide 】

  • 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 2025.02

    ISSN  2397-3366

    　View Summary

    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.

  • 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

    ISSN  17520894

    　View Summary

    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.

  • 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 2024.07

    Research paper (scientific journal), Joint Work, Lead author, Corresponding author, Accepted

  • 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 2023.12

    ISSN  00368075

    　View Summary

    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.

  • 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 )  2023.12

    　View Summary

    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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