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392 results on '"Yokobori, Shin-ichi"'

2. STXM-XANES analyses of Murchison meteorite samples captured by aerogel after hypervelocity impacts: A potential implication of organic matter degradation for micrometeoroid collection experiments

Author

Kebukawa, Yoko, Okudaira, Kyoko, Yabuta, Hikaru, Hasegawa, Sunao, Tabata, Makoto, Furukawa, Yoshihiro, Ito, Motoo, Nakato, Aiko, Kilcoyne, AL David, Kobayashi, Kensei, Yokobori, Shin-ichi, Imai, Eiichi, Kawaguchi, Yuko, Yano, Hajime, and Yamagishi, Akihiko

Subjects
Earth Sciences, Geology, micrometeoroid, meteorite, impact, organic matter, Tanpopo mission, Geochemistry, Geochemistry & Geophysics
Abstract

The Tanpopo mission is an astrobiology space experiment at the Japanese Experiment Module (JEM) 'Kibo' on the International Space Station (ISS). One of the sub-divided themes of the Tanpopo mission is for the intact capture of organic bearing micrometeoroids in low Earth orbit using ultralow density silica aerogel (0.01 g/cm 3 ). In order to evaluate damage to organic matter in micrometeoroids during hyper velocity impacts into the aerogel, Murchison meteorite powdered samples, analogs of organic bearing micrometeoroids, were fired into flight-grade silica aerogel (0.01 g/cm 3 ) using a two-stage light-gas gun with velocities of 4.4 and 5.9 km/s. The recovered Murchison grains were analyzed using scanning transmission X-ray microscopy/X-ray absorption near edge structure (STXM/XANES), transmission electron microscopy (TEM) and nanoscale secondary ion mass spectrometry (NanoSIMS). TEM observation did not show significant modifications of the recovered Murchison grains. Carbon-XANES spectra, however, showed a large depletion of the organic matter after the 5.9 km/s impact, but no such effects nor any significant hydrogen isotopic fractionation were observed after the 4.4 km/s impact.

Published
2019

4. Reconstructed ancestral enzymes suggest long-term cooling of Earth’s photic zone since the Archean

Author

Garcia, Amanda K, Schopf, J William, Yokobori, Shin-Ichi, Akanuma, Satoshi, and Yamagishi, Akihiko

Subjects
Life Below Water, Archaea, Archaeal Proteins, Bacterial Proteins, Cyanobacteria, Earth, Planet, Evolution, Molecular, Hydrothermal Vents, Nucleoside-Diphosphate Kinase, Oceans and Seas, Plant Proteins, Plants, Water Microbiology, ancestral sequence reconstruction, enzyme thermostability, nucleoside diphosphate kinase, phototroph, Precambrian
Abstract

Paleotemperatures inferred from the isotopic compositions (δ18O and δ30Si) of marine cherts suggest that Earth's oceans cooled from 70 ± 15 °C in the Archean to the present ∼15 °C. This interpretation, however, has been subject to question due to uncertainties regarding oceanic isotopic compositions, diagenetic or metamorphic resetting of the isotopic record, and depositional environments. Analyses of the thermostability of reconstructed ancestral enzymes provide an independent method by which to assess the temperature history inferred from the isotopic evidence. Although previous studies have demonstrated extreme thermostability in reconstructed archaeal and bacterial proteins compatible with a hot early Earth, taxa investigated may have inhabited local thermal environments that differed significantly from average surface conditions. We here present thermostability measurements of reconstructed ancestral enzymatically active nucleoside diphosphate kinases (NDKs) derived from light-requiring prokaryotic and eukaryotic phototrophs having widely separated fossil-based divergence ages. The ancestral environmental temperatures thereby determined for these photic-zone organisms--shown in modern taxa to correlate strongly with NDK thermostability--are inferred to reflect ancient surface-environment paleotemperatures. Our results suggest that Earth's surface temperature decreased over geological time from ∼65-80 °C in the Archean, a finding consistent both with previous isotope-based and protein reconstruction-based interpretations. Interdisciplinary studies such as those reported here integrating genomic, geologic, and paleontologic data hold promise for providing new insight into the coevolution of life and environment over Earth history.

Published
2017

5. Ultralow-density double-layer silica aerogel fabrication for the intact capture of cosmic dust in low-Earth orbits

Author

Tabata, Makoto, Kawai, Hideyuki, Yano, Hajime, Imai, Eiichi, Hashimoto, Hirofumi, Yokobori, Shin-ichi, and Yamagishi, Akihiko

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The fabrication of an ultralow-density hydrophobic silica aerogel for the intact capture cosmic dust during the Tanpopo mission is described. The Tanpopo experiment performed on the International Space Station orbiting the Earth includes the collection of terrestrial and interplanetary dust samples on a silica aerogel capture medium exposed to space for later ground-based biological and chemical analyses. The key to the mission's success is the development of high-performance capture media, and the major challenge is to satisfy the mechanical requirements as a spacecraft payload while maximizing the performance for intact capture. To this end, an ultralow-density (0.01 g cm$^{-3}$) soft aerogel was employed in combination with a relatively robust 0.03 g cm$^{-3}$ aerogel. A procedure was also established for the mass production of double-layer aerogel tiles formed with a 0.01 g cm$^{-3}$ surface layer and a 0.03 g cm$^{-3}$ open-topped, box-shaped base layer, and 60 aerogel tiles were manufactured. The fabricated aerogel tiles have been demonstrated to be suitable as flight hardware with respect to both scientific and safety requirements., Comment: To be published in J. Sol-Gel Sci. Technol., 10 pages, 5 figures, 1 table

Published
2015
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6. Design of a silica-aerogel-based cosmic dust collector for the Tanpopo mission aboard the International Space Station

Author

Tabata, Makoto, Imai, Eiichi, Yano, Hajime, Hashimoto, Hirofumi, Kawai, Hideyuki, Kawaguchi, Yuko, Kobayashi, Kensei, Mita, Hajime, Okudaira, Kyoko, Sasaki, Satoshi, Yabuta, Hikaru, Yokobori, Shin-ichi, and Yamagishi, Akihiko

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

We are developing a silica-aerogel-based cosmic dust collector for use in the Tanpopo experiment to be conducted on the International Space Station. The mass production of simple two-layer hydrophobic aerogels was undertaken in a contamination-controlled environment, yielding more than 100 undamaged products. The collector, comprising an aerogel tile and holder panel, was designed to resist launch vibration and to conform to an exposure attachment. To this end, a box-framing aerogel with inner and outer densities of 0.01 and 0.03 g/cm$^3$, respectively, was fabricated. The aerogel mounted in the panel passed random vibration tests at the levels of the acceptance and qualification tests for launch. It also withstood the pressure changes expected in the airlock on the International Space Station., Comment: To be published in Trans. JSASS Aerospace Tech. Japan, 6 pages, 6 figures

Published
2014
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7. Eukaryotes Appearing

Author

Yokobori, Shin-ichi, Furukawa, Ryutaro, Yamagishi, Akihiko, editor, Kakegawa, Takeshi, editor, and Usui, Tomohiro, editor

Published
2019
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8. Tanpopo cosmic dust collector: Silica aerogel production and bacterial DNA contamination analysis

Author

Tabata, Makoto, Kawaguchi, Yuko, Yokobori, Shin-ichi, Kawai, Hideyuki, Takahashi, Jun-ichi, Yano, Hajime, and Yamagishi, Akihiko

Subjects
Physics - Instrumentation and Detectors, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Hydrophobic silica aerogels with ultra-low densities have been designed and developed as cosmic dust capture media for the Tanpopo mission which is proposed to be carried out on the International Space Station. Glass particles as a simulated cosmic dust with 30 \mu m in diameter and 2.4 g/cm^3 in density were successfully captured by the novel aerogel at a velocity of 6 km/s. Background levels of contaminated DNA in the ultra-low density aerogel were lower than the detection limit of a polymerase chain reaction assay. These results show that the manufactured aerogel has good performance as a cosmic dust collector and sufficient quality in respect of DNA contamination. The aerogel is feasible for the biological analyses of captured cosmic dust particles in the astrobiological studies., Comment: 6 pages, 5 figures

Published
2011
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21. ポストたんぽぽ計画の進捗状況

Author

MILOJEVIC, Tetyana, MITA, Hajime, YANO, Hajime, SAKON, Itsuki, KOBAYASHI, Kensei, KEBUKAWA, Yoko, TOMITA-YOKOTANI, Kaori, NAKAGAWA, Kazumichi, SUGIMOTO, Manabu, YAMAGICHI, Akihiko, YOKOBORI, Shin-ichi, BESSHO, Yoshitaka, KATOH, Hiroshi, ABE, Tomoko, ENDO, Izumi, KIMURA, Shunta, ONG, Midori, OHMORI, Masayuki, FUJITA, Tomomichi, SUZUKI, TOshisada, ASANO, Maki, OKUDAIRA, Kyoko, and IMAI, Eiichi

Abstract

第36回宇宙環境利用シンポジウム (2022年1月18日-19日. オンライン開催), Space Utilization Research (January 18-19, 2022. Online Meeting), 著者人数: 23名ほか, 資料番号: SA6000168002, G-01

Published
2022

22. Development of Microbial Exposure Device with Culture Function

Author

HASHIMOTO, Hirofumi and YOKOBORI, Shin-ichi

Subjects
Artemis program, Microorganism exposure, Tanpopo mission, Culture function
Abstract

第36回宇宙環境利用シンポジウム (2022年1月18日-19日. オンライン開催), Space Utilization Research (January 18-19, 2022. Online Meeting), 資料番号: SA6000168004, G-03

Published
2022

23. Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein

Author

Hashimoto, Takuma, Horikawa, Daiki D., Saito, Yuki, Kuwahara, Hirokazu, Kozuka-Hata, Hiroko, Shin-I, Tadasu, Minakuchi, Yohei, Ohishi, Kazuko, Motoyama, Ayuko, Aizu, Tomoyuki, Enomoto, Atsushi, Kondo, Koyuki, Tanaka, Sae, Hara, Yuichiro, Koshikawa, Shigeyuki, Sagara, Hiroshi, Miura, Toru, Yokobori, Shin-ichi, Miyagawa, Kiyoshi, Suzuki, Yutaka, Kubo, Takeo, Oyama, Masaaki, Kohara, Yuji, Fujiyama, Asao, Arakawa, Kazuharu, Katayama, Toshiaki, Toyoda, Atsushi, and Kunieda, Takekazu

Published
2016
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29. The Possible Interplanetary Transfer of Microbes: Assessing the Viability of Deinococcus spp. Under the ISS Environmental Conditions for Performing Exposure Experiments of Microbes in the Tanpopo Mission

Author

Kawaguchi, Yuko, Yang, Yinjie, Kawashiri, Narutoshi, Shiraishi, Keisuke, Takasu, Masako, Narumi, Issay, Satoh, Katsuya, Hashimoto, Hirofumi, Nakagawa, Kazumichi, Tanigawa, Yoshiaki, Momoki, Yoh-hei, Tanabe, Maiko, Sugino, Tomohiro, Takahashi, Yuta, Shimizu, Yasuyuki, Yoshida, Satoshi, Kobayashi, Kensei, Yokobori, Shin-ichi, and Yamagishi, Akihiko

Published
2013
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31. Space Exposure of Amino Acids and Their Precursors during the Tanpopo Mission

Author

Kobayashi, Kensei, primary, Mita, Hajime, additional, Kebukawa, Yoko, additional, Nakagawa, Kazumichi, additional, Kaneko, Takeo, additional, Obayashi, Yumiko, additional, Sato, Tomohito, additional, Yokoo, Takuya, additional, Minematsu, Saaya, additional, Fukuda, Hitoshi, additional, Oguri, Yoshiyuki, additional, Yoda, Isao, additional, Yoshida, Satoshi, additional, Kanda, Kazuhiro, additional, Imai, Eiichi, additional, Yano, Hajime, additional, Hashimoto, Hirofumi, additional, Yokobori, Shin-ichi, additional, and Yamagishi, Akihiko, additional

Published
2021
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34. 祖先タンパク質復元に基づくタンパク質合成系初期進化の解析

Author

YOKOBORI, Shin-ichi, MABA, Masaki, HASHIMOTO, Chihiro, SASAMOTO, Toshihiro, MATSUDA, Naoki, MURAMATSU, Ayaka, ENDO, Yuki, MIYASHITA, Natsumi, MARUYAMA, Maho, YOKOAGAWA, Takashi, FURUKAWA, Ryutaro, and YAMAGISHI, Akihiko

Abstract

第35回宇宙環境利用シンポジウム(2021年1月19日-20日. オンライン開催), Space Utilization Research (January 19-20, 2021. Online Meeting), 著者人数: 13名, 資料番号: SA6000156031, レポート番号: S-07

Published
2021

35. たんぽぽ計画：全宇宙曝露試料の帰還と微生物資料解析の現状

Author

YAMAGISHI, Akihiko, HASHIOMTO, Hirofumi, YANO, Hajime, YOKOBORI, Shin-ichi, KAWAGUCHI, Yuko, KOBAYASHI, Kensei, MITA, Hajime, YABUTA, Hikaru, HIGASHIDE, Masumi, TABATA, Makoto, KAWAI, Hideyuki, IMAI, Eiichi, TOMITA-YOKOTANI, Kaori, KIMURA, Shunta, NARUMI, Issay, YATABE, Jun, FUJIWARA, Daisuke, KATOH, Hiroshi, ONG, Midori, and TOKITA, Miku

Abstract

第35回宇宙環境利用シンポジウム(2021年1月19日-20日. オンライン開催), Space Utilization Research (January 19-20, 2021. Online Meeting), 著者人数: 20名, 資料番号: SA6000156025, レポート番号: S-01

Published
2021

36. Summary of Tanpopo Exposure Panel Temperature Measurement

Author

HASHIMOTO, Hirofumi, IMAI, Eiichi, YANO, Hajime, YOKOBORI, Shin-ichi, and YAMAGISHI, Akihiko

Subjects
Tanpopo, Temperature measurement, Bimetal thermometer, ISS, ExHAM, JEM, EF
Abstract

第35回宇宙環境利用シンポジウム(2021年1月19日-20日. オンライン開催), Space Utilization Research (January 19-20, 2021. Online Meeting), 資料番号: SA6000156018, レポート番号: G-10

Published
2021

40. An actin homolog of the archaeon Thermoplasma acidophilum that retains the ancient characteristics of eukaryotic actin

Author

Hara, Futoshi, Yamashiro, Kan, Nemoto, Naoki, Ohta, Yoshinori, Yokobori, Shin-ichi, Yasunaga, Takuo, Hisanaga, Shin-ichi, and Yamagishi, Akihiko

Subjects
Lactobacillus acidophilus -- Genetic aspects, Lactobacillus acidophilus -- Research, Actin -- Research, Actin -- Structure, Eukaryotes -- Genetic aspects, Eukaryotes -- Research, Biological sciences
Abstract

Actin, a central component of the eukaryotic cytoskeleton, plays a crucial role in determining cell shape in addition to several other functions. Recently, the structure of the archaeal actin homolog Ta0583, isolated from the archaeon Thermoplasma acidophilum, which lacks a cell wall, was reported by Roeben et al. (J. Moi. Biol.358: 145-156, 2006). Here we show that Ta0583 assembles into bundles of filaments similar to those formed by eukaryotic actin. Specifically, Ta0583 forms a helix with a filament width of 5.5 nm and an axial repeating unit of 5.5 nm, both of which are comparable to those of eukaryotic actin. Eukaryotic actin shows a greater resemblance to Ta0583 than to bacterial MreB and ParM in terms of polymerization characteristics, such as the requirement for M[g.sup.2+], critical concentration, and repeating unit size. Furthermore, phylogenetic analysis also showed a closer relationship between Ta0583 and eukaryotic actin than between MreB or ParM and actin. However, the low specificity of Ta0583 for nucleotide triphosphates indicates that Ta0583 is more primitive than eukaryotic actin. Taken together, our results suggest that Ta0583 retains the ancient characteristics of eukaryotic actin.

Published
2007

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