2021/09/20 更新

写真a

カワバタ カズシゲ
川端 和重
KAWABATA Kazushige
所属
理事室 理事
職名
理事
外部リンク

学位

  • 理学博士 ( 1985年3月   北海道大学 )

研究キーワード

  • Biophysics

  • 生物物理学

  • モータータンパク

  • システム

  • 境界面

  • 単粒子追跡法

  • エイジング現象

  • 双晶

  • エンジング現象

  • 力学平衡

  • 断続性

  • アクチン繊維

  • 細胞運動

  • 有機結晶

  • 細胞骨格

  • 走査型プローブ顕微鏡

  • 細胞

  • 植物形態形成

  • 細胞コロニー

  • 運動

  • 断続運動

  • ミオシン

  • ダイナミクス

  • 強弾性

  • カオス

  • 双晶変形

  • 形態

  • 力学的メモリー効果

  • 境界

研究分野

  • 自然科学一般 / 数理物理、物性基礎

  • 自然科学一般 / 生物物理、化学物理、ソフトマターの物理

  • ライフサイエンス / 細胞生物学

  • ライフサイエンス / 生物物理学

  • 人文・社会 / 経営学

  • 自然科学一般 / 磁性、超伝導、強相関系

▶ 全件表示

経歴(researchmap)

  • 新潟大学   理事・副学長

    2018年2月 - 現在

      詳細を見る

  • 北海道大学   理事・副学長

    2013年4月 - 2017年3月

      詳細を見る

  • 北海道大学 大学院先端生命科学研究院   Faculty of Advanced Life Science   教授

    2011年4月 - 2018年1月

      詳細を見る

  • 北海道大学 大学院先端生命科学研究院   Faculty of Advanced Life Science   研究院長

    2011年4月 - 2013年3月

      詳細を見る

  • - Professor

    2010年

      詳細を見る

  • - 北海道大学 大学院先端生命科学研究院 先端融合科学研究部門 教授

    2010年

      詳細を見る

  • 北海道大学 大学院理学研究院 生命理学部門(生命融合科学分野) 教授   Faculty of Science, Department of Biological Sciences

    2006年 - 2010年

      詳細を見る

  • Professor

    2002年 - 2006年

      詳細を見る

  • 北海道大学大学院生物科学専攻(高分子機能学) 教授

    2002年 - 2006年

      詳細を見る

  • Associate Professor

    1995年 - 2002年

      詳細を見る

  • 北海道大学大学院理学研究科物理学専攻 助教授

    1995年 - 2002年

      詳細を見る

  • Associate Professor

    1994年 - 1995年

      詳細を見る

  • 北海道大学助教授(理学部物理学専攻) 助教授

    1994年 - 1995年

      詳細を見る

  • Researcher,Central research laboratory of Idemitsu Kosan Co. Ltd.

    1985年 - 1994年

      詳細を見る

  • 出光興産○中央研究所 研究員

    1985年 - 1994年

      詳細を見る

▶ 全件表示

学歴

  • 北海道大学   理学研究科   物理学専攻

    - 1985年

      詳細を見る

    国名: 日本国

    researchmap

  • 北海道大学

    - 1985年

      詳細を見る

  • 北海道大学   理学研究科   物理学専攻

    - 1982年

      詳細を見る

    国名: 日本国

    researchmap

  • 北海道大学

    - 1982年

      詳細を見る

  • 北海道大学   理学部   物理学科

    - 1980年

      詳細を見る

    国名: 日本国

    researchmap

  • 北海道大学

    - 1980年

      詳細を見る

▶ 全件表示

所属学協会

▶ 全件表示

委員歴

  • 文部科学省科学技術学術審議会 研究費部会   臨時委員  

    2021年3月 - 現在   

      詳細を見る

    団体区分:政府

    researchmap

  • 経済産業省   産学イノベーション人材循環育成研究会  

    2020年8月 - 現在   

      詳細を見る

    団体区分:政府

    researchmap

  • 文部科学省   公的研究費の適正な管理に関する有識者会議  

    2019年4月 - 現在   

      詳細を見る

    団体区分:政府

    researchmap

  • 文部科学省科学技術学術審議会   総合政策特別委員会委員  

    2017年12月 - 2021年3月   

      詳細を見る

    団体区分:政府

    researchmap

  • 科学技術・学術政策研究所   調査検討会 委員  

    2016年4月 - 現在   

      詳細を見る

    団体区分:政府

    researchmap

  • 大学評価・学位授与機構   国立大学教育研究評価委員会専門委員  

    2016年1月 - 2017年3月   

      詳細を見る

    団体区分:学協会

    researchmap

  • 日本政策投資銀行   地域アドバイザー  

    2015年12月 - 2017年3月   

      詳細を見る

    団体区分:その他

    researchmap

  • 文部科学省   中央教育審議会(初等中等教育分科会)特別チーム委員  

    2015年11月 - 2017年2月   

      詳細を見る

    団体区分:政府

    researchmap

  • 文部科学省   中央教育審議会(大学分科会) 臨時委員  

    2015年4月 - 現在   

      詳細を見る

    団体区分:政府

    researchmap

  • 文部科学省   科学技術・学術審議会(人材委員会) 臨時委員  

    2015年 - 現在   

      詳細を見る

    団体区分:政府

    researchmap

  • 北海道立総合研究機構   経営諮問会 委員  

    2013年4月 - 2017年3月   

      詳細を見る

    団体区分:自治体

    researchmap

  • 日本生物物理学会   北海道支部長  

    2003年 - 2004年   

      詳細を見る

    団体区分:学協会

    日本生物物理学会

    researchmap

▶ 全件表示

 

論文

  • Long-term observations reveal the formation process of branching systems of the genus Sasa in Bambusoideae 査読

    Hiroko Niimiya, Kazushige Kawabata

    AoB PLANTS   12 ( 5 )   plaa054   2020年9月

     詳細を見る

    担当区分:最終著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Oxford University Press (OUP)  

    <title>Abstract</title>
    Clarifying the endogenous processes that construct gross aerial shapes such as branching architecture in plants is crucial to understanding how branching contributes to plant adaptation to environments. Architectural analysis is powerful in decomposing the branching process, by comparing observations of plant growth among closely related taxa. The genus Sasa (Gramineae: Bambusoideae) contains three major sections Crassinodi, Sasa, and Macrochlamys. These sections exhibit characteristic branching architectures and are distributed separately across the Japanese archipelago, in relation to macroclimatic conditions such as snow accumulation. Our study aimed to quantitatively reveal the endogenous processes underlying branching architectures in the three sections of Sasa. Long term observations were carried out branch architectural development on Hokkaido Island from 1979 to 2012, which corresponded to the flowering interval of the genus. The results revealed that the three characteristic branching systems of the genus arise mainly from four endogenous processes (distribution of lateral buds on a culm, internode length arrangement along a culm, determination of the fate of lateral buds, development of branching with culm fragility due to aging) and their interactions with environmental conditions, especially snow accumulation. These processes are coordinated with each other over the lifespan of a single shoot in developing branching architecture.

    DOI: 10.1093/aobpla/plaa054

    researchmap

  • Compressive Stress Induces Dephosphorylation of the Myosin Regulatory Light Chain via RhoA Phosphorylation by the Adenylyl Cyclase/Protein Kinase A Signaling Pathway 査読

    Kenji Takemoto, Seiichiro Ishihara, Takeomi Mizutai, Kazushige Kawabata, Hisashi Haga

    PLOS ONE   10 ( 3 )   2015年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PUBLIC LIBRARY SCIENCE  

    Mechanical stress that arises due to deformation of the extracellular matrix (ECM) either stretches or compresses cells. The cellular response to stretching has been actively studied. For example, stretching induces phosphorylation of the myosin regulatory light chain (MRLC) via the RhoA/RhoA-associated protein kinase (ROCK) pathway, resulting in increased cellular tension. In contrast, the effects of compressive stress on cellular functions are not fully resolved. The mechanisms for sensing and differentially responding to stretching and compressive stress are not known. To address these questions, we investigated whether phosphorylation levels of MRLC were affected by compressive stress. Contrary to the response in stretching cells, MRLC was dephosphorylated 5 min after cells were subjected to compressive stress. Compressive loading induced activation of myosin phosphatase mediated via the dephosphorylation of myosin phosphatase targeting subunit 1 (Thr853). Because myosin phosphatase targeting subunit 1 (Thr853) is phosphorylated only by ROCK, compressive loading may have induced inactivation of ROCK. However, GTP-bound RhoA (active form) increased in response to compressive stress. The compression- induced activation of RhoA and inactivation of its effector ROCK are contradictory. This inconsistency was due to phosphorylation of RhoA (Ser188) that reduced affinity of RhoA to ROCK. Treatment with the inhibitor of protein kinase A that phosphorylates RhoA (Ser188) induced suppression of compression-stimulated MRLC dephosphorylation. Incidentally, stretching induced phosphorylation of MRLC, but did not affect phosphorylation levels of RhoA (Ser188). Together, our results suggest that RhoA phosphorylation is an important process for MRLC dephosphorylation by compressive loading, and for distinguishing between stretching and compressing cells.

    DOI: 10.1371/journal.pone.0117937

    Web of Science

    researchmap

  • Epithelial Sheet Folding Induces Lumen Formation by Madin-Darby Canine Kidney Cells in a Collagen Gel 査読

    Sumire Ishida, Ryosuke Tanaka, Naoya Yamaguchi, Genki Ogata, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga

    PLOS ONE   9 ( 8 )   e99655   2014年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PUBLIC LIBRARY SCIENCE  

    Lumen formation is important for morphogenesis; however, an unanswered question is whether it involves the collective migration of epithelial cells. Here, using a collagen gel overlay culture method, we show that Madin-Darby canine kidney cells migrated collectively and formed a luminal structure in a collagen gel. Immediately after the collagen gel overlay, an epithelial sheet folded from the periphery, migrated inwardly, and formed a luminal structure. The inhibition of integrin-beta 1 or Rac1 activity decreased the migration rate of the peripheral cells after the sheets folded. Moreover, lumen formation was perturbed by disruption of apical-basolateral polarity induced by transforming growth factor-beta 1. These results indicate that cell migration and cell polarity play an important role in folding. To further explore epithelial sheet folding, we developed a computer-simulated mechanical model based on the rigidity of the extracellular matrix. It indicated a soft substrate is required for the folding movement.

    DOI: 10.1371/journal.pone.0099655

    Web of Science

    researchmap

  • Substrate stiffness regulates temporary NF-κB activation via actomyosin contractions. 査読

    Ishihara S, Yasuda M, Harada I, Mizutani T, Kawabata K, Haga H

    Experimental cell research   319 ( 19 )   2916 - 2927   2013年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.yexcr.2013.09.018

    Web of Science

    PubMed

    researchmap

  • Irradiation-tolerant lung cancer cells acquire invasive ability dependent on dephosphorylation of the myosin regulatory light chain 査読

    Seiichiro Ishihara, Motoaki Yasuda, Takeshi Nishioka, Takeomi Mizutani, Kazushige Kawabata, Hiroki Shirato, Hisashi Haga

    FEBS LETTERS   587 ( 6 )   732 - 736   2013年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Radiotherapy is one of the major treatment modalities for malignancies. However, cells surviving irradiation often display high levels of invasiveness. This study shows that irradiation-tolerant lung adenocarcinoma demonstrates high invasive capability depending on dephosphorylation of the myosin regulatory light chain (MRLC). In a collagen gel overlay condition, low-invasive subclones of lung adenocarcinoma (A549P-3) showed a round morphology and diphosphorylation of MRLC. In contrast, irradiation-tolerant A549P-3 cells (A549P-3IR) displayed high invasiveness and a lower level of MRLC diphosphorylation. In addition, inhibition of MRLC phosphatase activity decreased the invasive activity. These findings suggest that A549P-3IR cells acquire high invasiveness through MRLC dephosphorylation. (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.

    DOI: 10.1016/j.febslet.2013.01.055

    Web of Science

    Scopus

    PubMed

    researchmap

  • Regulation of Cellular Contractile Force in Response to Mechanical Stretch by Diphosphorylation of Myosin Regulatory Light Chain via RhoA Signaling Cascade 査読

    Takeomi Mizutani, Kazushige Kawabata, Yoshikazu Koyama, Masayuki Takahashi, Hisashi Haga

    CELL MOTILITY AND THE CYTOSKELETON   66 ( 7 )   389 - 397   2009年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-LISS  

    Fibroblasts regulate their contractile force in response to external stretch; however, the detailed mechanism by which the force is regulated is unclear. Here, we show that diphosphorylation and dephosphorylation of myosin regulatory light chain (MRLC) are involved in the stretch-induced force response. Cellular stiffness, which reflects the cellular contractile force, under external stretch was measured by mechanical-scanning probe microscopy. Fibroblasts (NIH-3T3) expressing green fluorescent protein (GFP)-tagged mutant-type MRLC (MRLC(T18A)-GFP), which cannot be diphosphorylated, did not show any stretch-induced stiffness response, whereas the stiffness in cells expressing GFP-tagged wild-type MRLC(MRLC(WT)-GFP) increased immediately after the stretch and subsequently decreased after 1-2 h. Urea-PAGE western blot analysis showed that the proportion of diphosphorylated MRLC (PP-MRLC) transiently increased after the stretch and decreased after 1-2 h. Dominant-negative RhoA (RhoA(N19))-expressing cells did not show the stiffness response to the stretch, whereas wild-type RhoA-expressing cells did. It was concluded that file Cellular force response originates in the stretch-induced diphosphorylation and dephosphorylation of MRLC and is regulated via the RhoA signaling cascade Cell Motil. Cytoskeleton 66: 389-397,2009. (C) 2009 Wiley-Liss, Inc.

    DOI: 10.1002/cm.20378

    Web of Science

    researchmap

  • Static friction of agar gels: Formation of contact junctions at frictional interface 査読

    T Nitta, H Kato, H Haga, K Nemoto, K Kawabata

    JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN   74 ( 11 )   2875 - 2879   2005年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PHYSICAL SOC JAPAN  

    We measure the static friction F-c of agar gels on glass substrates immersed in water. F-c is independent of the nominal contact area, and increases with the normal load and the duration t(w) of contact prior to sliding. Using a confocal laser-scanning microscope, many fine dark spots are clearly visible in the optical reflection distribution images on the glass interface in contact with the gel. The total area of the dark spots increases with t(w), corresponding qualitatively to that of F-c. These observations indicate that F-c originates from the formation of the contacting spots at the interface, which is not due to asperities of the gel surface alone but related to the drainage of water trapped by the gel polymer network at the frictional interface.

    DOI: 10.1143/JPSJ.74.2875

    Web of Science

    researchmap

  • Collective movement of epithelial cells on a collagen gel substrate 査読

    H Haga, C Irahara, R Kobayashi, T Nakagaki, K Kawabata

    BIOPHYSICAL JOURNAL   88 ( 3 )   2250 - 2256   2005年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BIOPHYSICAL SOCIETY  

    Collective cell movement acts as an efficient strategy in many physiological events, including wound healing, embryonic development, and morphogenesis. We found that epithelial cells (Madin-Darby canine kidney cell) migrated collectively along one direction on a collagen gel substrate. Time-lapse images of Madin-Darby canine kidney cells cultured on type-I collagen gels and glass substrates were captured by phase contrast microscopy equipped with an incubation system. On the gel substrate, the directions of cell movement gradually converged on one direction as the number of cells increased, whereas the cells moved randomly on the glass substrate. We also observed "leader'' cells, which extended large lamellae and were accompanied by many "follower'' cells, migrating in the direction of oriented collagen fibers. The mean-squared displacement of each cell movement and the spatial correlation function calculated from the spatial distribution of cell velocity were obtained as functions of observation time. In the case of the gel substrate, the spatial correlation length increased gradually, representing the collectiveness of multicellular movement.

    DOI: 10.1529/biophysj.104.047654

    Web of Science

    researchmap

  • Cellular stiffness response to external deformation: Tensional homeostasis in a single fibroblast 査読

    T Mizutani, H Haga, K Kawabata

    CELL MOTILITY AND THE CYTOSKELETON   59 ( 4 )   242 - 248   2004年12月

     詳細を見る

    担当区分:最終著者   記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-LISS  

    Stiffness responses of fibroblasts were measured by scanning probe microscopy, following elongation or compression by deformation of an elastic substrate by 8%. The cellular stiffness, reflecting intracellular tension acting along stress fibers, decreased or increased instantly in response to the elongating or compressing stimuli, respectively. After this rapid change, the fibroblasts gradually recovered to their initial stiffness during the following 2 h, and then stabilized. The cells did not show conspicuous changes in shape after the 8% deformation during the SPM measurements. Fluorescence examination for GFP-actin demonstrated that the structure of the stress fibers was not altered noticeably by this small degree of deformation. Treatment with Y-27632, to inhibit myosin phosphorylation and abrogate cellular contractility, eliminated the change in stiffness after the mechanical elongation. These results indicate that fibroblasts possess a mechanism that regulates intracellular tension along stress fibers to maintain the cellular stiffness in a constant equilibrium state. (C) 2004 Wiley-Liss, Inc.

    DOI: 10.1002/cm.20037

    Web of Science

    researchmap

  • Intermittent motion of a twin boundary in (TMTSF)(2)PF2 査読

    K Kawabata, T Saga, K Matsuda, K Nemoto, T Sambongi

    EUROPHYSICS LETTERS   64 ( 1 )   118 - 123   2003年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:E D P SCIENCES  

    We observe the intermittent motion of a single planar twin boundary under a constant shear stress in organic crystals (TMTSF)(2)PF6. The boundary is forced to shuttle repeatedly in a specific region of a single crystal. For each move we measure the residence time t(res) at a certain trap as well as the local velocity v(local) in the vicinity of the trap. We find that tres varies largely on every move even under a well-controlled constant stress, while v(local) is almost constant. This wide distribution of t(res) can be well characterized by a lognormal function. The autocorrelation of log t(res) series exhibits apparently an exponential decay. To reveal the mechanism of the boundary motion we examine the temperature dependence of vlocal and find the boundary driven by thermal activation. On the other hand, the shear stress dependence of 1/t(res), an effective velocity at the trap, is found similar to that of v(local). The result indicates that the boundary does not make a complete stop at the trap but creeps very slowly. We also propose a phenomenological description for the characteristic feature of t(res).

    DOI: 10.1209/epl/i2003-00145-8

    Web of Science

    researchmap

  • Time dependent static friction force of agar gel-on-glass plate immersed in water 査読

    T Nitta, H Haga, K Kawabata

    JOURNAL DE PHYSIQUE IV   12 ( PR9 )   319 - 320   2002年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:E D P SCIENCES  

    We measured the static friction force of agar gel-on-glass plate ill water The static friction force is independent of the apparent contact area between the agar gel and file glass plate. It increases with waiting time, that is, contact duration prior to motion. The static friction force is represented well by a power law of waiting time. The waiting time dependence is different from those of solid-on-solid systems. These results arc discussed, based oil asperity contact model.

    DOI: 10.1051/jp4:20020426

    Web of Science

    researchmap

  • Drastic change of local stiffness distribution correlating to cell migration in living fibroblasts 査読

    M Nagayama, H Haga, K Kawabata

    CELL MOTILITY AND THE CYTOSKELETON   50 ( 4 )   173 - 179   2001年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY-LISS  

    Sequential images of the local stiffness distribution of living fibroblasts (NIH3T3) were captured under a culture condition using scanning probe microscopy in a force modulation mode. We found a clear relation between cell mi-ration and local stiffness distribution on the cell: When cells were stationary at one position, the stiffness distribution of their cellular surface was quite stable. On the other hand, once the cells started to move, the stiffness in their nuclear regions drastically decreased. Possible explanations for the correlation between the cell mi-ration and the cell stiffness are proposed. Cell Motil. Cytoskeleton 50: 173-179,2001. (C) 2001 Wiley-Liss, Inc.

    DOI: 10.1002/cm.10008

    Web of Science

    researchmap

  • Differential localization of non-muscle myosin II isoforms and phosphorylated regulatory light chains in human MRC-5 fibroblasts 査読

    T Saitoh, S Takemura, K Ueda, H Hosoya, M Nagayama, H Haga, K Kawabata, A Yamagishi, M Takahashi

    FEBS LETTERS   509 ( 3 )   365 - 369   2001年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    We investigated the localization of non-muscle myosin II isoforms and mono- (at serine 19) and diphosphorylated (at serine 19 and threonine 18) regulatory light chains (RLCs) in motile and non-motile MRC-5 fibroblasts. In migrating cells, myosin IIA localized to the lamella and throughout the posterior region. Myosin IIB colocalized with myosin HA to the posterior region except at the very end. Diphosphorylated RLCs were detected in the restricted region where myosin HA was enriched. In non-motile cells, myosin IIA was enriched in peripheral stress fibers with diphosphorylated RLCs, but myosin IIB was not. Our results suggest that myosin HA may be highly activated by diphosphorylation of RLCs and primarily involved in cell migration. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.

    DOI: 10.1016/S0014-5793(01)03186-6

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Motion of twin boundary in (TMTSF)(2)X. Comparison with DW dynamics 査読

    T Sambongi, T Yokoyama, T Saga, K Kawabata

    JOURNAL DE PHYSIQUE IV   9 ( P10 )   297 - 298   1999年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:E D P SCIENCES  

    Dyanamics of twin boundary mechanically introduced into crystals of (TMTSF)(2)X was studied. Repeated motion of isolated twin boundary was observed under constant external force in the same area was observed with controlled conditions. Effect of various controlling factors as well as of temperature is discussed.

    DOI: 10.1051/jp4:19991077

    Web of Science

    researchmap

  • Abnomal ferromagnetic behaviour for pyrolytic carbon under low temperature growth 査読

    Shigeyoshi Mizogami, Makoto Mizutani, Masahiko Fukuda, Kazushige Kawabata

    Synthetic Metals   43 ( 1-2 )   3271 - 3274   1991年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Abnormal ferromagnetic behavior was found for the pyrolytic carbon obtained from adamantane as a raw material by CVD method under low temperature growth. An clear hysteresis loop in its magnetization curve was observed even at room temperature. Such a ferromagnetic behavior was reproducible. Both the highly oriented structure and a large number of unpaired electrons were observed and seem to play important role for this observed ferromagnetism. This ferromagnetic behavior should be intrinsic property of this pyrolytic carbon because any ferromagnetic impurities like Fe are not detected in these samples within experimental accuracy. © 1991.

    DOI: 10.1016/0379-6779(91)91284-H

    Scopus

    researchmap

  • Electronic properties of (TTF)18(I3)18(CH2Cl2)2 under high pressure 査読

    K. Kawabata, K. tanaka, M. Mizutani

    Synthetic Metals   42 ( 1-2 )   1917 - 1920   1991年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Electrical conductivity of a single crystal of (TTF)18(I3)18(CH2Cl2)2 was measured under high pressure up to 20kb. At ambient pressure, the conductivity was semiconducting but an anomalous deviation from the linearity in its log σ vs. 1/T curve at about 220K. This knee was suppressed by applying pressure. Furthermore another conductive deviation was observed around room temperature under 20kb. The results are discussed in terms of two phase transitions. © 1991.

    DOI: 10.1016/0379-6779(91)91981-F

    Scopus

    researchmap

  • Superconducting organic thin films prepared using an evaporation technique 招待 査読

    Kazushige Kawabata, Keiji Tanaka, Makoto Mizutani

    Advanced Materials   3 ( 3 )   157 - 159   1991年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Wiley-VCH Verlag  

    DOI: 10.1002/adma.19910030309

    Scopus

    researchmap

  • Conducting thin films of α-(BEDT-TTF)2I3 by evaporation method 査読

    K. Kawabata, K. Tanaka, M. Mizutani

    Solid State Communications   74 ( 2 )   83 - 86   1990年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Thin films have been prepared by using the charge-transfer complex (BEDT-TTF) iodide as the raw material by a vacuum evaporation method. The electric conductivity in the film plane was as high as 2 S cm at room temperature. The conductivity measurement and X-ray examinations for as-grown specimens revealed that the films were composed of highly c-axis oriented α-(BEDT-TTF)2I3. Examinations on annealed specimens also provided another proof for the above conclusion. © 1990.

    DOI: 10.1016/0038-1098(90)90610-N

    Scopus

    researchmap

  • Electronic and magnetic properties of (TTF)18(I3)18(CH2Cl2)2 査読

    K. Kawabata, K. Tanaka, R. Hasegawa, M. Mizutani

    Solid State Communications   71 ( 5 )   361 - 364   1989年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The electric conductivity and the static magnetic susceptibility have been measured for single crystals of (TTF)18(I3)18(CH2Cl2)2 (TTF: tetrathiafulvalene), having a novel structure composed of three different types of segregated stacking columns of TTF molecules along the [101] crystal axis. The conductivity was highly anisotropic, and its temperature dependence was semiconductive. The crystals exhibited the Curie paramagnetism below the room temperature. These results could be explained on the basis of the characteristics of the crystal structure of the material. © 1989.

    DOI: 10.1016/0038-1098(89)90771-0

    Scopus

    researchmap

  • Impurity Elfects on Superconductivity and Charge Density Waves in NbSe3 査読

    Kazushige Kawabata

    Journal of the Physical Society of Japan   54 ( 2 )   762 - 770   1985年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The superconducting transition temperature Tc and the sizes of the resistive anomalies due to both the q1- and the qz-CDW formations are examined on single crystals of Ta-doped NbSe3. With addition of Ta, Tc increases steeply from below 70 mK to 1.7 K but turns to decrease at 5 at %Ta. The sizes of the resistive anomalies due to both CDW formations initially decrease but that due to the q1-CDW begins to increase at 5 at% where Tc turns to decrease. These results are discussed in terms of the competition between superconductivity and the CDW formations. The upper critical field is also measured in the superconducting state induced by Ta doping. The critical fleld shows one-dimensional anisotropy, which originates from the anisotropy of the electronic band structure. © 1985, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

    DOI: 10.1143/JPSJ.54.762

    Scopus

    researchmap

  • Evidence for extrinsic superconductivity in NbSe3 査読

    K. Kawabata, M. Ido

    Solid State Communications   44 ( 12 )   1539 - 1542   1982年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Detailed resistivity measurements and X-ray and microscopic examinations revealed that pure NbSe3 does not show superconductivity at least above 0.38K at ambient pressure. The superconductivity with the sluggish, current-sensitive transition curve, which has been observed frequently, is extrinsic and arises only from the crystal boundaries in the polycrystalline sample. © 1982.

    DOI: 10.1016/0038-1098(82)90673-1

    Scopus

    researchmap

  • Hall Effect of NbSe3 in the Non-Ohmic Regimes Below 58 K and 142 K CDW Transitions 査読

    Kazushige Kawabata, Masayuki Ido, Takashi Sambongi

    Journal of the Physical Society of Japan   50 ( 6 )   1992 - 1997   1981年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The Hall effect in NbSe3 was measured in the non-Ohmic regimes below the charge-density-wave (CDW) transitions at 142 K and 58 K. In both regimes, relation between the Hall voltage and the current becomes nonlinear above the threshold electric-field ET while linear relation remains between the Hall voltage and the electric field. Both nonlinearities of the conductivity and the Hall voltage are consistently explained by taking into consideration a new current-carrying mechanism which contributes only to the conductivity along the b-axis above ET. The new mechanism is attributed to the sliding CDW. In NbSe3, the CDW's are expected to slide only along the b-axis as inferred from the Ohmic transverse conductivity along the c-axis. © 1981, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

    DOI: 10.1143/JPSJ.50.1992

    Scopus

    researchmap

  • Highly Conductive 1 : 1 Radical Cation Salts of Anthra [1, 9-cd : 4, 10-c'd'] bis [1, 2] dichalcogenoles 査読

    TAKIMIYA K, OHNISHI A, ASO Y, OTSUBO T, OGURA F, KAWABATA K, TANAKA K, MIZUTANI M

    Bulletin of Chemical Society of Japan   67 ( 3 )   766 - 772   1974年

     詳細を見る

  • Role of ATF5 in the invasive potential of diverse human cancer cell lines 査読

    Akihiro Nukuda, Hiroki Endoh, Motoaki Yasuda, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   474 ( 3 )   509 - 514   2016年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Activating transcription factor 5 (ATF5) is a member of the ATF/CAMP response element-binding protein family. Our research group recently revealed that ATF5 expression increases the invasiveness of human lung carcinoma cells. However, the effects of ATF5 on the invasive potential of other cancer cells lines remain unclear. Therefore, in this study, we investigated the role of ATF5 in the invasive activity of diverse human cancer cell lines. Invasiveness was assessed using Matrigel invasion assays. ATF5 knockdown resulted in decreased invasiveness in seven of eight cancer cell lines tested. These results suggest that ATF5 promotes invasiveness in several cancer cell lines. Furthermore, the roles of ATF5 in the invasiveness were evaluated in three-dimensional (3D) culture conditions. In 3D collagen gel, HT-1080 and MDA-MB-231 cells exhibited high invasiveness, with spindle morphology and high invasion speed. In both cell lines, knockdown of ATF5 resulted in rounded morphology and decreased invasion speed. Next, we showed that ATF5 induced integrin-alpha 2 and integrin-beta 1 expression and that the depletion of integrin-alpha 2 or integrin-beta 1 resulted in round morphology and decreased invasion speed. Our results suggest that ATF5 promotes invasion by inducing the expression of integrin-alpha 2 and integrin-beta 1 in several human cancer cell lines. (C) 2016 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2016.04.131

    Web of Science

    researchmap

  • Data set for comparison of cellular dynamics between human AAVS1 locus-modified and wild-type cells 査読

    Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    DATA IN BRIEF   6   793 - 798   2016年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    This data article describes cellular dynamics, such as migration speed and mobility of the cytoskeletal protein, of wild-type human fibroblast cells and cells with a modified adeno-associated virus integration site 1 (AAVS1) locus on human chromosome 19. Insertion of exogenous gene into the AAVS1 locus has been conducted in recent biological researches. Previously, our data showed that the AAVS1-modification changes cellular contractile force (Mizutani et al., 2015 <THESTERM>[1]</THESTERM>). To assess if this AAVS1-modification affects cell migration, we compared cellular migration speed and turnover of cytoskeletal protein in human fibroblasts and fibroblasts with a green fluorescent protein gene knocked-in at the AAVS1 locus in this data article. Cell nuclei were stained and changes in their position attributable to cell migration were analyzed. Fluorescence recovery was observed after photobleaching for the fluorescent protein-tagged myosin regulatory light chain. Data here are related to the research article Transgene Integration into the Human AAVS1 Locus Enhances Myosin II-Dependent Contractile Force by Reducing Expression of Myosin Binding Subunit 85 <THESTERM>[1]</THESTERM>. (C) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CCBY license.

    DOI: 10.1016/j.dib.2015.12.053

    Web of Science

    researchmap

  • Heterogeneous filament network formation by myosin light chain isoforms effects on contractile energy output of single cardiomyocytes derived from human induced pluripotent stem cells 査読

    Takeomi Mizutani, Kazuya Furusawa, Hisashi Haga, Kazushige Kawabata

    REGENERATIVE THERAPY   3   90 - 96   2016年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) are expected to play an important role in heart therapies, in which hiPSC-CMs should generate sufficient contractile force to pump blood. However, recent studies have shown that the contractility of myocardial mimics composed of hiPSC-CMs is lower than that of adult human myocardium. To examine the mechanism by which contractile force output of hiPSC-CMs is weakened, we measured the contractile force of single hiPSC-CMs and observed the fibrous distribution of myosin II regulatory light chain (MRLC) of cardiac (contributes to beating) and non-cardiac (does not contribute to beating) isoforms. Single hiPSC-CMs were cultured on an extracellular matrix gel, and the contractile force and strain energy exerted on the gel were measured. Strain energy was not uniform between cells and ranged from 0.2 to 5.8 pJ. The combination of contractile force measurement and immunofluorescent microscopy for MRLC isoforms showed that cells with higher strain energy expressed the weakened non-cardiac myosin II fibers compared to those of cells with lower strain energy. Observation of cardiac and non-cardiac MRLC showed that the MRLC isoforms formed heterogeneous filament networks. These results suggest that strain energy output from single hiPSC-CMs depends both cardiac and non-cardiac myosin fibers, which prevent deformation of the cell body. (c) 2016, The Japanese Society for Regenerative Medicine. Production and hosting by Elsevier B.V.

    DOI: 10.1016/j.reth.2016.02.009

    Web of Science

    researchmap

  • An improved method for western blotting when extracting proteins from mammalian cells cultured on a collagen gel under serum-free conditions 査読

    Seiichiro Ishihara, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga

    CYTOTECHNOLOGY   68 ( 1 )   25 - 32   2016年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Western blotting is a widely used method for detection and quantification of specific proteins extracted from mammalian cells. In the conventional method of protein extraction, we found that collagen-containing gels interfered with detection of the p65 protein (one of the subunits in the NF-kappa B family of proteins) in human lung adenocarcinoma A549 cells cultured on a collagen gel containing serum. In contrast, the collagen gels did not affect detection of the GAPDH protein. Then, we established an improved method for preparation of protein extracts (using trichloroacetic acid fixation and collagenase treatment) from the cells cultured on the collagen gel. Using the improved method, we were able to detect p65 proteins without loss in A549 cells cultured on a collagen gel under serum-free conditions, but we could not detect the proteins if serum was present in cell culture. Thus, using western blotting and serum-free culture conditions, we succeeded in comparing the p65 expression between the cells grown in a plastic dish and cells grown on a collagen gel.

    DOI: 10.1007/s10616-014-9766-4

    Web of Science

    researchmap

  • Transgene integration into the human AAVS1 locus enhances myosin II-dependent contractile force by reducing expression of myosin binding subunit 85 査読

    Takeomi Mizutani, Rui Li, Hisashi Haga, Kazushige Kawabata

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   465 ( 2 )   270 - 274   2015年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    The adeno-associated virus site 1 (AAVS1) locus in the human genome is a strong candidate for gene therapy by insertion of an exogenous gene into the locus. The AAVS1 locus includes the coding region for myosin binding subunit 85 (MBS85). Although the function of MBS85 is not well understood, myosin II-dependent contractile force may be affected by altered expression of MBS85. The effect of altered expression of MBS85 on cellular contractile force should be examined prior to the application of gene therapy. In this study, we show that transgene integration into AAVS1 and consequent reduction of MBS85 expression changes myosin II-dependent cellular contractile force. We established a human fibroblast cell line with exogenous DNA knocked-in to AAVSI (KI cells) using the CRISPR/Cas9 genome editing system. Western blotting analysis showed that KI cells had significantly reduced MBS85 expression. KI cells also showed greater cellular contractile force than control cells. The increased contractile force was associated with phosphorylation of the myosin II regulatory light chain (MRLC). Transfection of KI cells with an MBS85 expression plasmid restored cellular contractile force and phosphorylation of MRLC to the levels in control cells. These data suggest that transgene integration into the human AAVS1 locus induces an increase in cellular contractile force and thus should be considered as a gene therapy to effect changes in cellular contractile force. (C) 2015 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2015.08.018

    Web of Science

    researchmap

  • Three-dimensional morphogenesis of MDCK cells induced by cellular contractile forces on a viscous substrate 査読

    Misako Imai, Kazuya Furusawa, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga

    SCIENTIFIC REPORTS   5 ( 14208 )   1 - 10   2015年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Substrate physical properties are essential for many physiological events such as embryonic development and 3D tissue formation. Physical properties of the extracellular matrix such as viscoelasticity and geometrical constraints are understood as factors that affect cell behaviour. In this study, we focused on the relationship between epithelial cell 3D morphogenesis and the substrate viscosity. We observed that Madin-Darby Canine Kidney (MDCK) cells formed 3D structures on a viscous substrate (Matrigel). The structures appear as a tulip hat. We then changed the substrate viscosity by genipin (GP) treatment. GP is a cross-linker of amino groups. Cells cultured on GP-treated-matrigel changed their 3D morphology in a substrate viscosity-dependent manner. Furthermore, to elucidate the spatial distribution of the cellular contractile force, localization of mono-phosphorylated and di-phosphorylated myosin regulatory light chain (P-MRLCs) was visualized by immunofluorescence. P-MRLCs localized along the periphery of epithelial sheets. Treatment with Y-27632, a Rho-kinase inhibitor, blocked the P-MRLCs localization at the edge of epithelial sheets and halted 3D morphogenesis. Our results indicate that the substrate viscosity, the substrate deformation, and the cellular contractile forces induced by P-MRLCs play crucial roles in 3D morphogenesis.

    DOI: 10.1038/srep14208

    Web of Science

    researchmap

  • Stiff substrates increase YAP-signaling-mediated matrix metalloproteinase-7 expression 査読

    A. Nukuda, C. Sasaki, S. Ishihara, T. Mizutani, K. Nakamura, T. Ayabe, K. Kawabata, H. Haga

    ONCOGENESIS   4   e165   2015年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Abnormally stiff substrates have been shown to trigger cancer progression. However, the detailed molecular mechanisms underlying this trigger are not clear. In this study, we cultured T84 human colorectal cancer cells on plastic dishes to create a stiff substrate or on collagen-I gel to create a soft substrate. The stiff substrate enhanced the expression of matrix metalloproteinase-7 (MMP-7), an indicator of poor prognosis. In addition, we used polyacrylamide gels (2, 67 and 126 kPa) so that the MMP-7 expression on the 126-kPa gel was higher compared with that on the 2-kPa gel. Next, we investigated whether yes-associated protein (YAP) affected the MMP-7 expression. YAP knockdown decreased MMP-7 expression. Treatment with inhibitors of epidermal growth factor receptor (EGFR) and myosin regulatory light chain (MRLC) and integrin-alpha 2 or integrin-beta 1 knockdown downregulated MMP-7 expression. Finally, we demonstrated that YAP, EGFR, integrin-alpha 2 beta 1 and MRLC produced a positive feedback loop that enhanced MMP-7 expression. These findings suggest that stiff substrates enhanced colorectal cancer cell viability by upregulating MMP-7 expression through a positive feedback loop.

    DOI: 10.1038/oncsis.2015.24

    Web of Science

    researchmap

  • Leader cells regulate collective cell migration via Rac activation in the downstream signaling of integrin beta 1 and PI3K 査読

    Naoya Yamaguchi, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga

    SCIENTIFIC REPORTS   5 ( 7656 )   1 - 8   2015年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:NATURE PUBLISHING GROUP  

    Collective cell migration plays a crucial role in several biological processes, such as embryonic development, wound healing, and cancer metastasis. Here, we focused on collectively migrating Madin-Darby Canine Kidney (MDCK) epithelial cells that follow a leader cell on a collagen gel to clarify the mechanism of collective cell migration. First, we removed a leader cell from the migrating collective with a micromanipulator. This then caused disruption of the cohesive migration of cells that followed in movement, called "follower'' cells, which showed the importance of leader cells. Next, we observed localization of active Rac, integrin beta 1, and PI3K. These molecules were clearly localized in the leading edge of leader cells, but not in follower cells. Live cell imaging using active Rac and active PI3K indicators was performed to elucidate the relationship between Rac, integrin beta 1, and PI3K. Finally, we demonstrated that the inhibition of these molecules resulted in the disruption of collective migration. Our findings not only demonstrated the significance of a leader cell in collective cell migration, but also showed that Rac, integrin beta 1, and PI3K are upregulated in leader cells and drive collective cell migration.

    DOI: 10.1038/srep07656

    Web of Science

    researchmap

  • Filamin B Enhances the Invasiveness of Cancer Cells into 3D Collagen Matrices 査読

    Yuta Iguchi, Seiichiro Ishihara, Yoshimi Uchida, Kaori Tajima, Takeomi Mizutani, Kazushige Kawabata, Hisashi Haga

    CELL STRUCTURE AND FUNCTION   40 ( 2 )   61 - 67   2015年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Numerous types of cancer cells migrate into extracellular tissues. This phenomenon is termed invasion, and is associated with poor prognosis in cancer patients. In this study, we demonstrated that filamin B (FLNb), an actin-binding protein, is highly expressed in cancer cell lines that exhibit high invasiveness, with a spindle morphology, into 3D collagen matrices. In addition, we determined that knockdown of FLNb in invasive cancer cells converts cell morphology from spindle-shaped, which is associated with high invasiveness, to round-shaped with low invasiveness. Furthermore, di-phosphorylation of myosin regulatory light chain (MRLC) and phosphorylation of focal adhesion kinase (FAK) are inhibited in FLNb-knockdown cancer cells. These results suggest that FLNb enhances invasion of cancer cells through phosphorylation of MRLC and FAK. Therefore, FLNb may be a new therapeutic target for invasive cancers.

    Web of Science

    researchmap

  • Modulation of extracellular conditions prevents the multilayering of the simple epithelium 査読

    Takeomi Mizutani, Kazuki Takeda, Hisashi Haga, Mitsugu Todo, Kazushige Kawabata

    HISTOCHEMISTRY AND CELL BIOLOGY   141 ( 5 )   473 - 481   2014年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    Simple epitheliums in normal glandular systems are regulated not to stratify even though the constituent cells proliferate and will rise from the epithelium. Since epithelial cells have the potential to establish cell-cell adhesions, the avoidance of stratification must be related to the intracellular signal cascades and the extracellular conditions. The contributions of the former are becoming clarified, but the influence of the latter is poorly understood. In the present study, we examined whether the frequency of cell-on-cell adhesion, which mimics the early stage of multilayering, is dependent on the type of the extracellular scaffold protein. Wild-type epithelial cells were cultured on E-cadherin-Fc (a cell-cell adhesion protein) or collagen (an extracellular matrix protein), and then, green fluorescent protein (GFP)-positive cells were seeded onto these wild-type cells. We observed that the cell-on-cell adhesion (adhesion of the GFP-positive cell to the wild-type cells) was more frequent in the E-cadherin-Fc treatment than the collagen treatment. The cell-on-cell adhesions that were observed in the E-cadherin treatment were transient and decreased in frequency to that of the collagen treatment after the 12 h of cell culture. We observed the disappearance of E-cadherin-Fc but not collagen during cell culture. These results suggest that transient multilayering in simple epithelium is possible, depending on the types of extracellular scaffold protein, and they imply that cells can modify the extracellular conditions to meet normal cellular conditions.

    DOI: 10.1007/s00418-013-1176-8

    Web of Science

    researchmap

  • Coating extracellular matrix proteins on a (3-aminopropyl)triethoxysilane-treated glass substrate for improved cell culture 査読

    Hiro-taka Masuda, Seiichiro Ishihara, Ichiro Harada, Takeomi Mizutani, Masayori Ishikawa, Kazushige Kawabata, Hisashi Haga

    BIOTECHNIQUES   56 ( 4 )   172 - 179   2014年4月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BIOTECHNIQUES OFFICE  

    We demonstrate that a (3-aminopropyl)triethoxysilane-treated glass surface is superior to an untreated glass surface for coating with extracellular matrix (ECM) proteins when used as a cell culture substrate to observe cell physiology and behavior. We found that MDCK cells cultured on untreated glass coated with ECM removed the coated ECM protein and secreted different ECM proteins. In contrast, the cells did not remove the coated ECM protein when seeded on (3-aminopropyl)triethoxysilane-treated (i.e., silanized) glass coated with ECM. Furthermore, the morphology and motility of cells grown on silanized glass differed from those grown on non-treated glass, even when both types of glass were initially coated with laminin. We also found that cells on silanized glass coated with laminin had higher motility than those on silanized glass coated with fibronectin. Based on our results, we suggest that silanized glass is a more suitable cell culture substrate than conventional non-treated glass when coated by ECM for observations of ECM effects on cell physiology.

    DOI: 10.2144/000114156

    Web of Science

    researchmap

  • Lung Cancer Cells That Survive Ionizing Radiation Show Increased Integrin α2β1- and EGFR-Dependent Invasiveness 査読

    Xue Li, Seiichiro Ishihara, Motoaki Yasuda, Takeshi Nishioka, Takeomi Mizutani, Masayori Ishikawa, Kazushige Kawabata, Hiroki Shirato, Hisashi Haga

    PLoS ONE   8 ( 8 )   e70905   2013年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Ionizing radiation (IR)-enhanced tumor invasiveness is emerging as a contributor to the limited benefit of radiotherapy; however, its mechanism is still unclear. We previously showed that subcloned lung adenocarcinoma A549 cells (P cells), which survived 10 Gy IR (IR cells), acquired high invasiveness in vitro. Here, we tried to identify the mechanism by which IR cells increase their invasiveness by examining altered gene expression and signaling pathways in IR cells compared with those in P cells. To simulate the microenvironment in vivo, cells were embedded in a three-dimensional (3D) collagen type I gel, in which the IR cells were elongated, while the P cells were spherical. The integrin expression pattern was surveyed, and expression levels of the integrin α2 and β1 subunits were significantly elevated in IR cells. Knockdown of α2 expression or functional blockade of integrin α2β1 resulted in a round morphology of IR cells, and abrogated their invasion in the collagen matrix, suggesting the molecule&#039;s essential role in cell spread and invasion in 3D collagen. Epidermal growth factor receptor (EGFR) also presented enhanced expression and activation in IR cells. Treatment with EGFR tyrosine kinase inhibitor, PD168393, decreased the ratio of elongated cells and cell invasiveness. Signaling molecules, including extracellular signal-regulated kinase-1/2 (Erk1/2) and Akt, exhibited higher activation in IR cells. Inhibition of Akt activation by treating with phosphoinositide 3-kinase (PI3K) inhibitor LY294002 decreased IR cell invasion, whereas inhibition of Erk1/2 activation by mitogen-activated protein kinase kinase (MEK) inhibitor U0126 did not. Our results show that integrin α2β1 and EGFR cooperatively promote higher invasiveness of IR-survived lung cancer cells, mediated in part by the PI3K/Akt signaling pathway, and might serve as alternative targets in combination with radiotherapy. © 2013 Li et al.

    DOI: 10.1371/journal.pone.0070905

    Web of Science

    Scopus

    PubMed

    researchmap

  • Active fluctuation in the cortical cytoskeleton observed by high-speed live-cell scanning probe microscopy 査読

    Kazushi Tamura, Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    ACTA BIOMATERIALIA   7 ( 10 )   3766 - 3772   2011年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCI LTD  

    We investigated the dynamics of the cortical cytoskeleton in living cells by analyzing the motion of the endogenous components of the cytoskeleton using scanning probe microscopy (SPM). We performed molecular characterization of the microgranules visualized by SPM in living cells and analyzed the motion of these microgranules via particle tracking. Simultaneous SPM and epifluorescence microscopy observations showed that the microgranules recruited not only actin but also cortactin, which can bind to actin filaments. This indicates condensation of actin filaments at microgranules, leading us to identify them as "cytoskeletal microdomains". High-speed SPM observation and particle-tracking analysis showed that these cytoskeletal microdomains exhibit random walk-like diffusive fluctuations over a timescale of seconds. Inhibition of the molecular motor myosin II, which drives actin filaments, led to subdiffusive fluctuations of the microdomains. These results can be explained by longitudinal sliding of actin filaments stochastically driven by myosin II and the bending motion of the actin filaments in the absence of sliding. Analysis of the cytoskeletal microdomains thus revealed the intrinsic dynamics of the cortical cytoskeleton. (C) 2011 Acts Materialia Inc. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.actbio.2011.06.013

    Web of Science

    researchmap

  • Precise Synthesis and Physicochemical Properties of High-Density Polymer Brushes designed with Poly(N-isopropylacrylamide) 査読

    Hiromasa Suzuki, Huda Muhammad Nurul, Takahiro Seki, Taisuke Kawamoto, Hisashi Haga, Kazushige Kawabata, Yukikazu Takeoka

    MACROMOLECULES   43 ( 23 )   9945 - 9956   2010年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER CHEMICAL SOC  

    A high-density polymer brush of poly(N-isopropylacrylamide) (PNIPA) was precisely prepared following carefully selected procedures, which included selecting the underlying substrate, preparing its surface, and grafting PNIPA on the substrate. As a result, the graft density and the dried thickness of the brush reached more than 0.5 chains/nm(2) and 200 nm, respectively, for the best combination of each procedure. This high-density polymer brush showed gradual collapse with increasing temperature in water, which must be attributed to both the low swelling and the low shrinking abilities of the brush that result from the physically constrained state of the polymers. The contact angle of the air bubbles underneath the high-density polymer brush also gradually decreased up to around 25 degrees C in water with increasing temperature, which indicates that the hydrophilicity of the surface decreases as it does in typical PNIPA-grafted membranes and gels. Starting at the lower critical solution temperature of free PNIPA in water, approximately 32 degrees C, the value of the contact angle started to increase dramatically, and it became constant when the solution temperature exceeded 40 degrees C. Ultimately, the surface exhibited a mostly hydrophilic nature at higher temperatures. The temperature-dependent contact angles can be interpreted by assuming that the terminally chlorinated alkyl groups of the elongated PNIPAs can be positioned on the surfaces or hidden in the vicinity of the membranes, depending on the temperature of the solution.

    DOI: 10.1021/ma101439f

    Web of Science

    CiNii Article

    researchmap

  • Nano-mechanical properties of living cells expressing constitutively active RhoA effectors 査読

    Kazushi Tamura, Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   403 ( 3-4 )   363 - 367   2010年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Filamentous actin and myosin-II are major determinants of cell mechanics and are tightly regulated by a small guanosine triphosphatase, RhoA, and its downstream effectors. We examined the effects of constitutively active mutants of RhoA effectors, which have not been reported before, on cortical stiffness of living cells by using scanning probe microscopy, fluorescence microscopy, and truncated mutants of RhoA effectors labeled with a fluorescent protein. Our data indicated that expression of a constitutively active mutant of Dial, a formin-family actin polymerizer, enhanced cortical stiffness and increased actin filament quantity in cells. Furthermore, expression of a constitutively active mutant of Rho-associated coiled-coil kinase, a myosin-II activator, softened the cell cortex but increased myosin-II activity. Our findings provide new insights into anomalous mechanics of cells, which is a topic of current interest in a variety of biological research fields. (C) 2010 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.bbrc.2010.11.036

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Intermediate structure between chromatin fibers and chromosome revealed by mechanical stretching and SPM measurement 査読 国際誌

    BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS   400 ( 1 )   181 - 186   2010年9月

     詳細を見る

    担当区分:最終著者   記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.bbrc.2010.08.041

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Integrin β1-dependent invasive migration of irradiation-tolerant human lung adenocarcinoma cells in 3D collagen matrix 査読

    ISHIHARA Seiichiro, HAGA Hisashi, YASUDA Motoaki, MIZUTANI Takeomi, KAWABATA Kazushige, SHIRATO Hiroki, NISHIOKA Takeshi

    Biochemical and Biophysical Research Communications   396 ( 3 )   651 - 655   2010年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/j.bbrc.2010.04.150

    Web of Science

    CiNii Article

    researchmap

  • Dynamics of leading lamellae of living fibroblasts visualized by high-speed scanning probe microscopy 査読

    Kazushi Tamura, Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    HISTOCHEMISTRY AND CELL BIOLOGY   133 ( 1 )   59 - 67   2010年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER  

    In this study, we aimed at improving the temporal resolution of scanning probe microscopy (SPM) for observing living cells by introducing soft cantilevers, low feedback-gain operations, and cantilever deflection imaging. We achieved visualization of the mechanical architecture in leading lamellae of living fibroblasts at a temporal resolution of around 10 s, which is higher than that of conventional contact-mode SPM. Time-lapse SPM could be used to monitor not only cytoskeletal dynamics but also the dynamics of numerous microgranules. Statistical analysis of microgranular motion revealed that the microgranules have superdiffusive behaviors and significant directional order of motion. We also found that the direction of their motion is correlated with the direction of growing actin stress fibers. The combination of SPM with fluorescence microscopy showed that vinculin, a component of cell-substratum adhesion sites, localizes at the microgranules. Our experimental data provides a new insight into the intracellular mechanical architecture and its structural dynamics, suggesting that high-speed live-cell SPM has great potential for investigating the structural origin of cellular dynamics.

    DOI: 10.1007/s00418-009-0644-7

    Web of Science

    researchmap

  • Mechanical response of single myoblasts to various stretching patterns visualized by scanning probe microscopy 査読

    Waka Mitsui, Kazushi Tamura, Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    ARCHIVES OF HISTOLOGY AND CYTOLOGY   72 ( 4-5 )   227 - 234   2009年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INT SOC HISTOLOGY & CYTOLOGY  

    The mechanical memory effect of single cells was reported in our recent study. In order to clarify this effect, various sequential stimuli of uniaxial deformation were applied to cells by deformable culture dishes and a deformation device, and the local stiffness distribution of single C2C12 myoblasts was visualized by scanning probe microscopy. Following a single step stretching, cellular stiffness first increased steeply and then gradually decreased for two hours. By a single step stretching 30 min after a long pulse-like deformation with a pulse duration of 30 min, the cells responded in the same way. On the other hand, they (lid not respond to a single step stretching 39 min after a short pulse-like deformation with a pulse duration of 0.5 min. These results indicated that cellular mechanical response to external deformation is affected strongly by a preceding deformation and that the duration time of the preceding deformation is an important factor in the change in mechanical response. We consider that the change in mechanical response contributes to a regulatory mechanism of cellular contractile force.

    DOI: 10.1679/aohc.72.227

    Web of Science

    researchmap

  • Wide range scanning probe microscopy for probing mechanical effects on cellular function 査読

    Takeomi Mizutani, Hisashi Haga, Kosaku Kato, Kazushige Kawabata

    ARCHIVES OF HISTOLOGY AND CYTOLOGY   72 ( 4-5 )   235 - 243   2009年12月

     詳細を見る

    記述言語:英語   出版者・発行元:INT SOC HISTOLOGY & CYTOLOGY  

    Scanning probe microscopy (SPM) provides a range of strategies for studying biological phenomena due to its ability to image surfaces under liquids. However, some cellular events, such as cell migration, exceed the maximum measurable range of SPM. Recently, we have developed a wide range scanning probe microscope (WR-SPM) to investigate cellular events which exceed the range of the conventional SPM. In this review, we introduce the instrumentation of the WR-SPM, which can measure a sample for 400 mu m in the xy directions and 23 mu m in the z direction. We then show the application of the WR-SPM to studies of the stiffness response of epithelial cells to an external loading force and demonstrat that the stiffness of the epithelial cells increases under stretched conditions. We also showed the results on the mesh structure on the surface of a melanoma cell as well as the regulatory mechanism of the cellular contractile force by the combined use of topographical and mechanical modes of the WR-SPM. These findings indicate that the WR-SPM is very useful for studying the functions of a cell in relation to the surface structure and mechanical properties of that cell.

    DOI: 10.1679/aohc.72.235

    Web of Science

    researchmap

  • Displacement of actin filament and actin binding proteins under local deformation processed by digital image correlation method in a myoblast 査読

    Takeomi Mizutani, Kenichi Doi, Yasuyuki Morita, Masakazu Uchino, Mitsugu Todo, Hisashi Haga, Kazushige Kawabata

    Journal of Biomechanical Science and Engineering   4 ( 3 )   415 - 422   2009年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Displacement of actin filament and its binding proteins in mouse myoblasts under locally applied deformation was analyzed by manual method or digital image correlation method. Cyotoskeletal components labeled by immunofluorescent technique or green fluorescent protein-fused protein were deformed via the movement of a glass needle which was poked into a cell. First, we confirmed the digital image correlation method is able to use to analyze displacement map by comparison of the manual method. Next, we examined whether the applied deformation isotropically propagates into cell body. At focal adhesions, fluorescent signals from the deformed area unchanged under the application. Mainly, focal adhesions around the poked area were moved to the direction of the movement of the needle. In addition, some adhesions away from the poked area were moved. Similar results were observed in phalloidin-stained cells. Finally, we applied the local deformation to live cells. However, displacement at the locally deformed area was not observed due to the disappearance of fluorescent signals. These results indicate that applied deformation propagated heterogeneously into a cell, and may imply that biochemical signals disrupt actin fibers under local deformation.

    DOI: 10.1299/jbse.4.415

    Scopus

    CiNii Article

    researchmap

  • Novel Function of Transcription Factor ATF5: Blockade of p53-dependent Apoptosis Induced by Ionizing Irradiation 査読

    Takeshi Nishioka, Yusuke Miyai, Hisashi Haga, Kazushige Kawabata, Hiroki Shirato, Akihiro Homma, Kenichiro Shibata, Motoaki Yasuda

    CELL STRUCTURE AND FUNCTION   34 ( 1 )   17 - 22   2009年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Purpose: To find a new molecule that affects p53-dependent radiosensitivity.Methods and Materials: A mouse sarcoma cell line, QRsP(p53+/+), was used. From this cell line, we established a radiosensitive clone and a radioresistant one. Colony assay, p53 gene transfer, a luciferase assay for p53 and p21, animal transplantation experiment, and DNA array analyses were performed.Results: Microarray showed marked reduction of a transcription factor, ATF5, both in vitro and in vivo for the radiosensitive clone. Interestingly, flow cytometric analysis demonstrated marked apoptosis for the radiosensitive clone by p53 cloned adenovirus infection. Luciferase reporter assay revealed that ATF5 suppressed the transactivational activity of p53 and p63. By ATF5 gene transfer, the radiosensitive clone regained resistance to both ionizing-radiation and Ad-p53 infection-induced cell death. Surprisingly, time-lapse cell migration observation revealed greater cell motility for ATF5-transfected radiosensitive clone.Conclusions: It seems likely that ATF5 is a potent repressor of p53 and elevated expression of ATF5 in a tumor may relate to enhanced malignant phenotypes, such as radioresistance or greater cell motility.

    DOI: 10.1247/csf.08041

    Web of Science

    CiNii Article

    researchmap

  • Mechanical response to isotropic shrinkage of fibroblasts measured by scanning probe microscopy 査読

    Taisuke Kawamoto, Hisashi Haga, Kazushi Tamura, Takeomi Mizutani, Kazushige Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS   47 ( 7 )   6173 - 6176   2008年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOCIETY APPLIED PHYSICS  

    Mechanical stimuli such as cyclic stretch and fluid stress affect various cellular physiologies, including proliferation. morphology. and differentiation. We investigated Cellular response to shrinking stimuli by developing an isotropic deformation device and observing cellular elasticity with mechanical scanning probe microscopy (M-SPM). The isotropic deformation device consists of a steel ring and a deformable elastic culture dish made of transparent silicone rubber. The M-SPM can visualize topography and spatial distribution of local elasticity of biomaterials in solution. Fibroblasts became softer in response to 6% shrinkage. Cell elasticity did not increase for 1 h after the shrinking stimulus. Inhibitory studies using lysophosphatidic acid and calyculin-A revealed that myosin light chain phosphatase leading to dephospholylation of myosin II regulatory light chain is involved in cell softening.

    DOI: 10.1143/JJAP.47.6173

    Web of Science

    researchmap

  • Visualization of stretch-induced intracellular tensional response of single fibroblasts by mechanical scanning probe microscopy 査読

    Kazushi Tamura, Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   46 ( 8B )   5631 - 5635   2007年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC APPLIED PHYSICS  

    This study was aimed at developing a novel experimental setup to investigate the tensional response of a single living cell to external deformation. We constructed the setup which consisted of three components: a device for applying various patterns of uniaxial deformation to living cells, a mechanical scanning probe microscope (M-SPM), and an optical microscope. Intracellular tension is reflected by cellular stiffness measured by M-SPM. Using the setup, we found that stiffness in some areas on a living fibroblast cell increased while stiffness in other areas decreased under 8% external single-step stretch. Furthermore, we found that repetitive deformation inhibited the increase in the stretch-induced cellular stiffness. The present setup is useful for investigating the characteristics of, intracellular tensional responses to external deformation.

    DOI: 10.1143/JJAP.46.5631

    Web of Science

    CiNii Article

    researchmap

  • Development of a device to stretch tissue-like materials and to measure their mechanical properties by scanning probe microscopy 査読

    Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    ACTA BIOMATERIALIA   3 ( 4 )   485 - 493   2007年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCI LTD  

    We have developed a new stretch device to investigate the biomechanical responses to an external loading force on a tissue-like material consisting of cells and a collagen gel. Collagen gel, a typical matrix found abundantly in the connective tissue, was attached to an elastic chamber that was precoated with a thin layer of collagen. Madin-Darby canine kidney cells that were cultured on the collagen gel were stretched in a uniaxial direction via deformation of the elastic chamber. Changes in the morphology and stiffness of the tissue-like structure were measured before and after the stretch using wide-range scanning probe microscopy (WR-SPM). The change in cellular morphology was heterogeneous, and there was a twofold increase in the intercellular junction due to the stretch. In addition to the WR-SPM measurements, this device enables observation of the spatial distribution of cytoskeletal proteins such as vimentin and alpha-catenin using immunofluorescent microscopy. We concluded that the stretch device we have reported in this paper is useful for measuring the mechanical response of a tissue-like material over a range of cell sizes when exposed to an external loading force. (c) 2006 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.actbio.2006.11.007

    Web of Science

    researchmap

  • Imaging mechanical properties of living cells by scanning probe microscopy 査読

    Hisashi Haga, Masafumi Nagayama, Kazushige Kawabata

    CURRENT NANOSCIENCE   3 ( 1 )   97 - 103   2007年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BENTHAM SCIENCE PUBL LTD  

    Scanning probe microscope (SPM) has been developed as a powerful tool for obtaining high resolution topographic images of biological samples in their natural aqueous environment. SPM can also be used to evaluate mechanical properties because its probe is physically in contact with the samples during measurement. To obtain cellular stiffness with SPM, we have proposed two methods: a force modulation mode and a force snapping mode. Considering the influence of the drag force of liquids, we have successfully improved the quantitative evaluation of cellular stiffness by using the force modulation mode. Experiments performed using the two methods revealed that the local stiffness of fibroblasts was not homogeneous on the cell surface but largely varied from point to point. It was revealed that spatial and temporal distributions of cellular stiffness originate in cytoskeletal distribution, mode of cellular migration, and intracellular contractile force.

    DOI: 10.2174/157341307779940580

    Web of Science

    researchmap

  • Physics of sliding friction of gels 査読

    Takahiro Nitta, Kazushige Kawabata

    JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS   52 ( 8 )   586 - 591   2007年

     詳細を見る

    記述言語:日本語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC TRIBOLOGISTS  

    Web of Science

    researchmap

  • Diphosphorylation of the myosin regulatory light chain enhances the tension acting on stress fibers in fibroblasts 査読

    Takeomi Mizutani, Hisashi Haga, Yoshikazu Koyama, Masayuki Takahashi, Kazushige Kawabata

    JOURNAL OF CELLULAR PHYSIOLOGY   209 ( 3 )   726 - 731   2006年12月

     詳細を見る

    記述言語:英語   出版者・発行元:WILEY-LISS  

    Regulation of the contractile force is crucial for cell migration, cell proliferation, and maintenance of cell morphology. Phosphorylation of the myosin II regulatory light chain (MRLC) is involved in these processes. To show whether the diphosphorylation of MRLC increases the tension acting on stress fibers, changes in the stiffness of fibroblasts expressing wild-type MRLC and a mutant type, which cannot be diphosphorylated, on treatment with lysophosphatidic acid (LPA) were examined by a mechanical-scanning probe microscope (M-SPM). The LPA treatment increased cellular stiffness in the wild-type MRLC expressing cells, while it had no effect on the mutated cells. immunostaining showed that LPA stimulation induced the diphosphorylation of MRLC. These results suggest that the diphosphorylation of MRLC enhances the tension acting on stress fibers.

    DOI: 10.1002/jcp.20773

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Observation of stiff domain structure on collagen gels by wide-range scanning probe microscopy 査読

    T Mizutani, H Haga, K Kato, K Matsuda, K Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   45 ( 3B )   2353 - 2356   2006年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INST PURE APPLIED PHYSICS  

    Spatial distributions for 100-mu m(2)-stiffness of type I collagen gels were measured by wide-range scanning probe microscopy. A cantilever being attached to the tip of a glass bead of 100 mu m diameter was used to reduce local stress during Measurements. This method enabled the cantilever to be ill contact With the gel Surface in it manner of it Hertzian contact model regardless of the rough meshwork formation of collagen gels. Stiffness images of collagen gets showed stiff domain structures With it size of 20 mu m. The more the concentration of collagen increased, the more the stiffness increased with the growth of stiff domain structures. Immunostaining for collagen molecules showed highly concentrated fibril structures as large as the stiff domain structures. These results indicate that the structure of collagen gel is nonuniform in the range of 100 mu m square, but it is heterogeneous because of collagen fibril aggregation.

    DOI: 10.1143/JJAP.45.2353

    Web of Science

    CiNii Article

    researchmap

  • The role of actin-binding protein filamin A in cellular stiffness and morphology studied by wide-range scanning probe microscopy 査読

    K Kato, Y Ohmori, T Mizutani, H Haga, K Ohashi, T Ito, K Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   45 ( 3B )   2328 - 2332   2006年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INST PURE APPLIED PHYSICS  

    The role of filamin A (FLNa) in the organization of stress fibers has been studied by comparing the mechanical properties of FLNa-deficient human melanoma cells (M2 cells) and M2 sub-line expressing FLNa (A7 cells). We measured both the topographies and the elasticity distributions of M2 and A7 cells by using a wide-range scanning probe microscopy. In A7 cells, we observed aligned fibrous structures, whereas in M2 cells, fibrous structures were dispersed randomly. Immunofluorescent observation revealed that the aligned fibrous structures in A7 cells were stress fibers generating intracellular tension. On the other hand, the reticular structures observed in M2 cells did not correspond to actin filaments. The cellular stiffness of A7 cells was approximately twice than that of M2 cells, indicating that A7 cells produce larger contractile force through the stress fibers. These results suggest that FLNa stabilizes the stress fibers and increases the cellular stiffness.

    DOI: 10.1143/JJAP.45.2328

    Web of Science

    CiNii Article

    researchmap

  • Spatiotemporal variation in cellular stiffness corresponding to development of morphological polarity 査読

    S Toko, T Mizutani, H Haga, K Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   44 ( 7B )   5451 - 5454   2005年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC APPLIED PHYSICS  

    The spatiotemporal variation in the local stiffness of fibroblasts was visualized successfully using wide-range scanning probe microscopy (SPM) in the force mapping mode when the cells attach and spread on a substratum, to clarify the cellular mechanical effects on the development of morphological polarity. We found that the stiffness distribution in inhomogeneous in a circular cell. When the cell shape is polarized, several stiff bands appear clearly along the direction of the morphological polarity. The SPM measurements give new information on the cellular mechanical effect on the development of morphological polarity.

    DOI: 10.1143/JJAP.44.5451

    Web of Science

    CiNii Article

    researchmap

  • Visualization of elasticity distribution of single human chromosomes by scanning probe microscopy 査読

    K Nomura, O Hoshi, D Fukushi, T Ushiki, H Haga, K Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS BRIEF COMMUNICATIONS & REVIEW PAPERS   44 ( 7B )   5421 - 5424   2005年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN SOC APPLIED PHYSICS  

    We succeeded in visualizing the spatial distribution of the local elasticity of mitotic human chromosomes in a liquid environment using scanning probe, microscopy (SPM). Force-versus-indentation curves (force curves) were collected over an entire single chromosome. To estimate the local elasticity of thin chromosomes from the force curves, we examined the validity of a previously proposed model that takes into account the effect of the finite thickness of samples on the estimation of the local elasticity. The force curves obtained are well represented by the model within a small indentation range. The elasticity obtained is independent of the indentation within an indentation range of 100nm. Such fitting procedures for the force curves collected are carried out over the entire chromosome, and the elasticity distribution of a single chromosome is visualized.

    DOI: 10.1143/JJAP.44.5421

    Web of Science

    CiNii Article

    researchmap

  • Contribution of cellular contractility to spatial and temporal variations in cellular stiffness 査読

    M Nagayama, H Haga, M Takahashi, T Saitoh, K Kawabata

    EXPERIMENTAL CELL RESEARCH   300 ( 2 )   396 - 405   2004年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ACADEMIC PRESS INC ELSEVIER SCIENCE  

    Scanning probe microscopy and immunofluorescence observations indicated that cellular stiffness was attributed to a contractile network structure consisting of stress fibers. We measured temporal variations in cellular stiffness when cellular contractility was regulated by dosing with lysophosphatidic acid or Y-27632. This experiment revealed a clear relation between cellular stiffness and contractility: Increases in contractility caused cells to stiffen. On the other hand, decreases in contractility reduced cellular stiffness. In both cases, not only the stiffness of the stress fibers but also that of the whole of the cell varied. Immunofluorescence observations of myosin II and vinculin indicated that the stiffness variations induced by the regulation of cellular contractility were mainly due to rearrangements of the contractile actin network on the dorsal surface. Taken together, our findings provide evidence that the actin cytoskeletal network and its contractility features provide and modulate the mechanical stability of adherent cells. (C) 2004 Elsevier Inc. All rights reserved.

    DOI: 10.1016/j.yexcr.2004.07.034

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Wide-range scanning probe microscopy for visualizing biomaterials in the submillimeter range 査読

    T Mizutani, H Haga, K Nemoto, K Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   43 ( 7B )   4525 - 4528   2004年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INST PURE APPLIED PHYSICS  

    We developed wide-range scanning probe microscope (WR-SPM) for visualizing the topography and mechanical properties of samples in the submillimeter range. A piezoelectric scanner with a maximum xy scan range of 400 pin square and a z range of 16 pin was constructed by joining two commercial piezotranslators in tandem. The reliability of measurement was confirmed by measuring a well-defined pattern engraved on a silicon substrate. Using the WR-SPM, the spatial distribution of stiffness and time-lapse images of a large colony consisting of approximately 40 epithelial cells were visualized Successfully, where the local stiffness was measured using the force mapping mode. These results indicate that the WR-SPM can be a powerful instrument to visualize the mechanical properties of biological phenomena extending in the submillimeter range.

    DOI: 10.1143/JJAP.43.4525

    Web of Science

    CiNii Article

    researchmap

  • Electronic properties of (DMTSA)BF4 at ambient pressure 査読

    M Nagasawa, K Kawabata, T Sambongi, P Monceau, T Otsubo

    J. de Phys. IV France   12 ( Pr9 )   317 - 318   2003年4月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    In the organic conductor (DMTSA)BFQ [DMTSA: 2,3-dimethyl-tetra-seleno-antracene], the electronic system is expected to be the Mott-Hubbard insulator. However, its conductivity at room temperature is 200similar to400Omega(-1)cm(-1) and behaves metallic above similar to200K. At ambient pressure we found anomalies both in the DC conductivity components and in the permittivity at similar to80K, similar to those in (TMTTF)(2)X associated with charge ordering at similar to100K. Possible origin of the anomalies is discussed.

    DOI: 10.1016/S0379-6779(02)00756-7

    Web of Science

    CiNii Article

    researchmap

  • Visualization of dynamic organization of cytoskeleton gels in living cells by hybrid-SPM

    K Kawabata, Y Sado, M Nagayama, T Nitta, K Nemoto, Y Koyama, H Haga

    CHINESE JOURNAL OF POLYMER SCIENCE   21 ( 2 )   169 - 174   2003年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER-VERLAG BERLIN  

    We succeeded in performing of hybrid Scanning Probe Microscopy (hybrid-SPM) in which mechanical-SPM and fluorescence microscopy are combined. This technique is able to measure simultaneously mechanical properties and distribution of cytoskeletons of living cells by using green fluorescent protein. We measured evolution of both local elasticity and distributions of actin stress fibers in an identical fibroblast living in physiological conditions. The SPM experiments revealed that stiffer lines develop in living cells, which correspond to actin stress fibers. The elasticity of the actin stress fibers is as high as 100 kPa. We discuss mechanical effects on the development of actin filament networks.

    Web of Science

    researchmap

  • Microdomain structure of agar gels observed by mechanical-scanning probe microscopy 査読

    T Nitta, Y Endo, H Haga, K Kawabata

    JOURNAL OF ELECTRON MICROSCOPY   52 ( 3 )   277 - 281   2003年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    The inhomogeneous structure of agar gels was examined by means of mechanical-scanning probe microscopy Several domains were observed in the elasticity images, while such domains could not be seen in the height images. The domain size decreased with increases in agar concentration. We found that the histograms of the logarithm of the local elastic modulus were described well by a single normal distribution. As the agar concentration increased, the peak values of the histograms increased, while the half-value width remained constant. These results imply that the gelation process of agar gels has a common mechanism, despite its complexity.

    DOI: 10.1093/jmicro/52.3.277

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Improvement of force modulation mode with scanning probe microscopy for imaging viscoelasticity of living cells 査読

    M Nagayama, H Haga, Y Tanaka, Y Hirai, M Kabuto, K Kawabata

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   41 ( 7B )   4952 - 4955   2002年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INST PURE APPLIED PHYSICS  

    We improved the force modulation mode with scanning probe microscopy (SPM) in order to make a quantitative evaluation of the viscoelasticity of living cells. Taking account of the viscosity of liquid medium, the vibration frequency of the cantilever was selected to be 500 Hz, and analysis of cantilever vibration was adopted for evaluation of the viscoelasticity of the samples. Consequently, we have succeeded in determining viscoelasticity distribution on living cells. The values of Young's modulus and the coefficient of viscosity vary from 10 to 50 kPa and from 20 to 40 Pa(.)s on a cell, depending on its internal cellular structure.

    DOI: 10.1143/JJAP.41.4952

    Web of Science

    CiNii Article

    researchmap

  • Non-linear conduction in insulating phase of (DMTSA)BF4 under high pressure 査読

    M Nagasawa, K Kawabata, T Sambongi, T Otsubo, N Mori

    SYNTHETIC METALS   120 ( 1-3 )   1059 - 1060   2001年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE SA  

    Organic conductor (DMTSA)BF4 is a compound composed of an electron donor DMTSA and a monovalent acceptor BF4-. The conductivity at room temperature is similar to 400 Omega (-1)cm(-1) and behaves metallic. At ambient pressure, the gradual metal-insulator transition was observed at similar to 200K. We found that the sample shows non-linear conduction in the insulating state under 0.35GPa. We discuss the apparent similarity with the non-linear electric conduction by the density wave sliding.

    DOI: 10.1016/S0379-6779(00)01218-2

    Web of Science

    CiNii Article

    researchmap

  • Mechanical effects on collective phenomena of biological systems: cell locomotion 査読

    Kazushige Kawabata, Masafumi Nagayama, Hisashi Haga, Takashi Sambongi

    CURRENT APPLIED PHYSICS   1 ( 1 )   66 - 71   2001年1月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Animal cells crawl in tissue to achieve their functions. The cell locomotion is a typical case of collective phenomena in biological systems. By atomic force microscopy (AFM), we measured the spatial distribution of local elasticity over cells of fibroblasts, which are kept alive in physiological conditions. The AFM experiments revealed that: (1) the nucleus area of the cell surface is about 10 times softer than the surroundings, and (2) distribution of local elasticity is evolving in time. The drug-dosing experiments confirm that the cell shape and stiffness originate mainly in actin filaments but not in microtubules. The elasticity pattern does not always correspond to that of actin filaments from fluorescence observations. These results indicate that the cell stiffness results not only from the density of actin filaments but also from their dynamical properties. (c) 2001 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S1567-1739(00)00013-4

    Web of Science

    researchmap

  • Evaluation of Viscoelasticity of Biological Cells in Liquid by Scanning Probe Microscopy 査読

    Yoshio Tanaka, Yoshihiko Hirai, Masaaki Kabuto, Kazushige Kawabata, Hisashi Haga, Masahumi Nagayama

    Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C   67 ( 663 )   3498 - 3504   2001年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    An analytical method is proposed to evaluate the viscoelasticity of a biomaterial in water by the scanning probe microscope. The proposed method utilizes the dependence of amplitude and phase lag of cantilever vibration on the viscoelasticity when the tip on the cantilever cyclically penetrates into the cell. The cyclical penetrations are carried out in two ways
    one is by excitation of the cantilever fixed end, and other by that of the table. The analysis takes the drag force of water due to the cantilever vibration into account. The stiffness and the viscosity of the cell are analytically related with the amplitude and the phase lag of the cantilever vibration. The results shows that the relations among the amplitude, the phase lag, stiffness and viscosity vary significantly depending on the excitation frequencies of the cantilever fixed end and the table. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.

    DOI: 10.1299/kikaic.67.3498

    Scopus

    researchmap

  • Real-time observation of twin boundary motion in organic crystal (TMTSF)(2)X 査読

    K Kawabata, Y Hosokawa, T Kawauchi, T Sambongi

    FERROELECTRICS   251 ( 1-4 )   199 - 205   2001年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:TAYLOR & FRANCIS LTD  

    Ferroelastic domain boundary can be regarded as a type of twin domain boundary. A twin deformation is induced in a conducting organic crystal (TMTSF)(2)X when the shear stress is applied. TMTSF denotes tetramethyle-tetraselenafulvalene and x does an anion such as ClO4+ and PF6+. The boundary can move easily along one direction under the small shear stress of about I kPa. We could successfully observe the motion of the isolated twin boundary in real time and investigate control parameters of its motion. The motion of the twin boundary is intermittent even under a constant stress. The boundary can move under stress above a small threshold. Temperature dependence of the local velocity strongly depends on the applied stress: when the temperature is lowered, the velocity increases under the small stress while decreases under the large stress. The local velocity depends not only on external stress and temperature but also on the waiting time before the onset of motion.

    DOI: 10.1080/00150190108008518

    Web of Science

    researchmap

  • Neuronal components of the superior and inferior tentacles in the terrestrial slug, Limax marginatus 査読

    Ito, I, H Nakamura, T Kimura, H Suzuki, T Sekiguchi, K Kawabata, E Ito

    NEUROSCIENCE RESEARCH   37 ( 3 )   191 - 200   2000年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER IRELAND LTD  

    To identify the types of neurons and to infer the patterns of connectivity in slug tentacles, we stained the neurons in the superior and inferior tentacles in the terrestrial slug, Limax marginatus, by backfilling of the tentacular nerves with Lucifer yellow. Four types of stained neurons, '(1) sensory neurons', '(2) gamma cells', '(3) ganglion cells', '(4) lateral cells', were identified both in the superior and inferior tentacles. Three subtypes of the sensory neurons, '(la) round sensory neurons', '(lb) spindle-shaped sensory neurons', and '(lc) small sensory neurons', were found in the digits. The gamma cells and the ganglion cells were interneurons. Three subtypes of gamma cells, '(2a) round monopolar gamma cells', '(2b) round bipolar gamma cells', and '(2c) large gamma cells', were present in the digits. The ganglion cells were composed of '(3a) monopolar ganglion cells','(3b) bipolar ganglion cells', and '(3c) elongated ganglion cells'. The monopolar and bipolar types were located both in the tentacular ganglia and digits, whereas the elongated type was present only in the tentacular ganglia. The lateral cells, whose function is unknown, were found in the dermo-muscular sheaths of the tentacles. Our study provides the first description of the neuronal map of inferior tentacles in gastropods. The results showed no differences in the morphological features of stained neurons between the superior and inferior tentacles in L. marginatus. (C) 2000 Elsevier Science Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

    DOI: 10.1016/S0168-0102(00)00118-8

    Web of Science

    researchmap

  • Mechanical properties of membrane surface of cultured astrocyte revealed by atomic force microscopy 査読

    H Shiga, Y Yamane, E Ito, K Abe, K Kawabata, H Haga

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   39 ( 6B )   3711 - 3716   2000年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    In order to examine the mechanical properties of the membrane surface of astrocytes, we observed living astrocytes by atomic force microscopy (AFM) both in contact mode and force-mapping mode. Ridge-like structures reflecting actin filaments were observed in the topographic images in contact mode, but not in force-mapping mode, using a zero-loading force. When we measured the elasticity of astrocytes, we observed that the cell membrane above the nucleus was soft and the cell membrane above the cytosol was stiff. In particular, the parts reflecting actin filaments were very stiff. This effect of actin filaments on the elasticity of astrocytes was confirmed by the loss of actin filaments after application of actin-polymerization inhibitor.

    DOI: 10.1143/JJAP.39.3711

    Web of Science

    CiNii Article

    researchmap

  • Comparing microscopic with macroscopic elastic properties of polymer gel 査読

    T Nitta, H Haga, K Kawabata, K Abe, T Sambongi

    ULTRAMICROSCOPY   82 ( 1-4 )   223 - 226   2000年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Measurements of the local elastic modulus of agar gels obtained with atomic force microscope (AFM) force mapping were compared with values obtained by the tensile creep method. The observed spatial distributions of the local elastic modulus over the gel surface in AFM elastic images clearly corresponded to the network structure of agar fibers observed both in AFM topographic and scanning electron microscope (SEM) images. Both peak and average values of distribution functions in the histograms of local elastic modulus increase monotonically with the agar concentration. Values obtained by AFM force mapping were found to be proportional to values obtained from creep experiments. (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0304-3991(99)00170-9

    Web of Science

    researchmap

  • Elasticity mapping of living fibroblasts by AFM and immunofluorescence observation of the cytoskeleton 査読

    H Haga, S Sasaki, K Kawabata, E Ito, T Ushiki, T Sambongi

    ULTRAMICROSCOPY   82 ( 1-4 )   253 - 258   2000年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:ELSEVIER SCIENCE BV  

    Using the force mapping mode of atomic force microscopy (AFM), we measured spatial distribution of elastic moduli of living mouse fibroblasts (NIH3T3) in a physiological condition. The nuclear portion of the cellular surface is about 10 times softer than the surroundings. Stiffer fibers are confirmed in the elastic images. In order to investigate origin of the softer nuclear portion and the stiffer fibers, we fixed the identical cells imaged by the AFM, and carried out immunofluorescence observation for three types of cytoskeletal filaments - actin filaments, microtubules, and intermediate filaments, using confocal laser scanning microscopy (CLSM). A comparison between the AFM and the CLSM images revealed that the elasticity of the cells was concerned not only with the distribution of actin network, but also with intermediate filaments, whereas microtubules had no large effect on the measured elasticity. (C) 2000 Elsevier Science B.V. All rights reserved.

    DOI: 10.1016/S0304-3991(99)00157-6

    Web of Science

    researchmap

  • Big softer hole on living cells: Elasticity imaging with AFM

    K Kawabata, H Haga, T Nitta, Y Endo, M Nagayama, E Ito, T Sambongi

    SCANNING AND FORCE MICROSCOPIES FOR BIOMEDICAL APPLICATIONS II   3922   91 - 98   2000年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPIE-INT SOC OPTICAL ENGINEERING  

    We have focused on effects of local mechanical properties of the cell on cell motion. By using atomic force microscopy, we measured spatial distribution of local elastic modulus on mouse fibroblasts (NIH3T3), which is living in a physiological condition. In order to examine validity of AFM elastic measurements, we measured local elastic modulus of gels as elastic reference materials. The results obtained with AFM were compared with values obtained by tensile creep method. It is veryfied that these values are proportional each other. The AFM experiments on living cells revealed that center area of cell surface is about 10 times softer than the surroundings and looks like a big softer hole in the elasticity image. We fixed the cell just after the AFM measurements and carried out immunofluorescence observation for cytoskeletal filaments of actin filaments, microtubules and intermediate filaments. A comparison between distribution of local elasticity and cytoskeletones indicates that harder area on the cell results mainly from concentration of actin filaments. However, We found that some areas like the big softer hole do not correspond to distribution of actin filaments.

    Web of Science

    researchmap

  • Real-time observation of twin boundary motion in crystals: an ideal dry friction system 査読

    K Kawabata, Y Hosokawa, T Saga, T Sambongi

    TRIBOLOGY LETTERS   9 ( 1-2 )   41 - 44   2000年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:BALTZER SCI PUBL BV  

    A twin boundary of an organic single crystal can move easily under a small stress. The boundary motion is intermittent, even under a constant stress. The local velocity depends not only on external stress but also on the waiting time before the onset of motion. The present system is considered as a simple system of dry Friction between two commensurate lattices. We found some similarities between the twin boundary motion and solid/solid dry friction.

    DOI: 10.1023/A:1018848225662

    Web of Science

    researchmap

  • Three-dimensional characterization of interior structures of exocytotic apertures of nerve cells using atomic force microscopy 査読

    T Tojima, Y Yamane, H Takagi, T Takeshita, T Sugiyama, H Haga, K Kawabata, T Ushiki, K Abe, T Yoshioka, E Ito

    NEUROSCIENCE   101 ( 2 )   471 - 481   2000年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:PERGAMON-ELSEVIER SCIENCE LTD  

    We examined the interior structure of exocytotic apertures in synaptic vesicles of neuroblastoma x glioma hybrid cells using atomic force microscopy. The atomic force microscopy detected apertures of 50-100 nm in diameter at various depths within the varicosities of these cells. We were also able to image a regular radial pattern on the wall and lump-like structures at the bottom of these apertures. In contrast, scanning electron microscopy could only detect the apertures but not the fine details of their interior. The cells examined here exhibited the same electrophysiological properties and expression of synaptophysin and syntaxin 1 as presynaptic terminals, as studied by various electrophysiological and imaging techniques.
    Our results indicate that atomic force microscopy allows three-dimensional viewing of the fine structures located inside exocytotic apertures in nerve cells. (C) 2000 IBRO. Published by Elsevier Science Ltd. All rights reserved.

    DOI: 10.1016/S0306-4522(00)00320-1

    Web of Science

    researchmap

  • Quantitative analyses of topography and elasticity of living and fixed astrocytes 査読

    Y Yamane, H Shiga, H Haga, K Kawabata, K Abe, E Ito

    JOURNAL OF ELECTRON MICROSCOPY   49 ( 3 )   463 - 471   2000年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    The topography and elasticity of living and fixed astrocytes cultured from the rat cerebra were studied quantitatively by atomic force microscopy (AFM). Ridge-like structures reflecting F-actin beneath the cell membrane were prominent in the contact-mode images of living astrocytes. Many of these ridges became unclear after fixation (2%, glutaraldehyde). In addition, the ridge-like structures were invisible in the topography of living cells observed at zero-loading force in the force mapping mode, which is considered to show the real cell surface not pressed down by an AFM tip. The topography of fixed cells observed both in the contact mode and at zero-loading force in the force mapping mode was similar to that of living cells observed at zero-loading force in the force mapping mode, although some deformed areas were detected in the fixed cells. The elasticity map images of living astrocytes showed that the cell membrane above the nucleus was softer (2-3 kPa) than the surroundings, and that the cell membrane above F-actin was stiffer (10-20 kPa) than the surroundings. In the elasticity map images of fixed astrocytes, on the other hand, the elasticity of the cells was found to be relatively uniform (200-700 kPa) irrespective of the inner structures of cells. These results show that images observed by AFM should be carefully examined in consideration of the force introduced to specimens and the elasticity of specimens to find out the real surface topography.

    Web of Science

    researchmap

  • Time-lapse viscoelastic imaging of living fibroblasts using force modulation mode in AFM 査読

    H Haga, M Nagayama, K Kawabata, E Ito, T Ushiki, T Sambongi

    JOURNAL OF ELECTRON MICROSCOPY   49 ( 3 )   473 - 481   2000年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:OXFORD UNIV PRESS  

    Using the force modulation mode in atomic force microscopy, we have succeeded in capturing time-lapse viscoelastic images of living mouse fibroblasts (NIH3T3) for several hours in a physiological condition without damaging the fibroblasts. Elongation of the lamellipodia and swelling of blabs were observed in time-lapse topographic images, which were taken every 10 min. The corresponding viscoelastic responses at a frequency of 600 Hz were visualized as consecutive images. The stiffer part of the cell body was fairly stable and did not show morphological changes for over 1 h. This is probably due to excess condensation of the actin network, hardening the cell cortex, and lowering the cytoskeletal activity. The nuclear portion of the cell body seems to be slightly less viscous than the peripheral region.

    Web of Science

    researchmap

  • Dynamics of astrocyte adhesion as analyzed by a combination of atomic force microscopy and immunocytochemistry: the involvement of actin filaments and connexin 43 in the early stage of adhesion 査読

    Y Yamane, H Shiga, H Asou, H Haga, K Kawabata, K Abe, E Ito

    ARCHIVES OF HISTOLOGY AND CYTOLOGY   62 ( 4 )   355 - 361   1999年10月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INT SOC HISTOLOGY & CYTOLOGY  

    We observed the time-dependent morphological alteration of astrocytes during their adhesion by atomic force microscopy (AFM) and investigated the relationships between this morphological alteration and the localization of actin filaments and connexin 43 by immunocytochemistry. The fine processes observed as fine ridge-like structures by AFM were closely concerned with ac tin filaments by immunocytochemistry, During the adhesion of astrocytes, actin filaments appeared to be aligned regularly beyond the borders among different cells. Detectable connexin immunoreactivity was changed in the following regions: 1) the tips of fine cell processes and the cell margin when astrocytes started to adhere; 2) the border of cells when astrocytes tightly adhered; and 3) non-specific sites when astrocytes became a cluster. In the former two cases, the immunopositive spots for connexin were observed to colocalize with the tips of cell processes with actin filaments. These results strongly suggest that connexin associated with actin filaments at the tip of cell processes plays an important role in the early stage of the adhesion of astrocytes. These observations afford valuable clues for understanding the glial communication.

    DOI: 10.1679/aohc.62.355

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Atomic force microscopic observation of three-dimensional morphological changes of neurons where stimulated by a neurotransmitter 査読

    T Hosono, M Yamanaka, T Tojima, Y Yamane, H Sadamoto, D Hatakeyama, H Haga, K Kawabata, K Abe, E Ito

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   38 ( 6B )   3940 - 3945   1999年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    As the first step in the study df morphological changes in neurons associated with their functional changes, we applied atomic force microscopy (AFM) for the observation of fine three-dimensional morphological changes in rat cerebellar granule cells stimulated by an agonist of glutamate receptors, N-methyl-D-aspartate (NMDA). The AFM revealed that NMDA changed the cross-sections of cell bodies from a trapezoid-like form to a triangle-like form within a minute. The fine hill-like structures on the top surfaces of the cell bodies became wider during the same period. These results were suggested to be induced by the depolymerization; of filamentous actin triggered by the entry of Ca2+ via cation channels complexed with the activated NMDA receptors.

    DOI: 10.1143/JJAP.38.3940

    Web of Science

    CiNii Article

    researchmap

  • Dynamics of isolated twin boundary in (TMTSF)(2)PF6 - Control of its mobility 査読

    M Mukoujima, K Kawabata, T Sambongi

    EUROPEAN PHYSICAL JOURNAL B   7 ( 3 )   365 - 369   1999年2月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SPRINGER VERLAG  

    Intermittent and irregular motion of isolated twin boundary (kink) in organic crystal (TMTSF)(2)PF6 was studied at room temperature. Both the local velocity and the time of intermission are determined not only by external stress and temperature but also by the time (t(w)) elapsed after the backward passage and before the following forward one. When the kink moves after longer t(w) its velocity becomes smaller and the time of intermission longer. Both tend to saturate for t(w) longer than 10(2) s. This result indicates that some disorder is induced in the lattice by the backward motion and it is relaxed during t(w). We also found that the effect of the backward motion of one kink on its following motion is equivalent quantitatively to that of the forward motion of the pair-created counterpart.

    DOI: 10.1007/s100510050623

    Web of Science

    researchmap

  • Time dependent viscoelastic image of living nerve cells using AFM 査読

    K Kawabata, H Ishizuka, T Nitta, H Haga, E Ito, K Abe, T Ushiki, T Sambongi

    BIOLOGICAL PHYSICS   487   235 - 239   1999年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    The topographic and viscoelastic images of the nerve cell (NG108-15) living in the culture medium were successfully obtained in the force modulation mode using atomic force microscopy(AFM), We found that there exists variation of elasticity in the cell, To compare the elastic results with F-actin network of cytoskeleton which is considered as a possible origin for cell stiffness, the fluorescence observation was made on the fu;ed cells just after the AFM measurements. The results show no clear correspondence between density of F-actin and stiffness of the cells.

    Web of Science

    researchmap

  • Reexamination of fine surface topography of nerve cells revealed by atomic force microscopy 査読

    Bioimages   7   89 - 94   1999年

     詳細を見る

  • Spatial and temporal viscoelastic imaging of living fibroblasts by atomic force microscopy 査読

    H Haga, S Sasaki, K Kawabata, E Ito, K Abe, T Sambongi

    BIOLOGICAL PHYSICS   487   229 - 234   1999年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:AMER INST PHYSICS  

    We have investigated viscoelastic properties of living mouse fibroblasts (NIH3T3) in a physiological condition using both force mapping and force modulation modes in atomic force microscopy. Spatial distribution of the elastic moduli has been measured using the force mapping mode. The nucleus area of the cell is about 10 times softer than the cytoplasm. Temporal changes in shape and viscoelasticity of developing lamellipodia have been captured using the force modulation mode. The dynamic changes were succeeded in capturing with time resolution of 10 minutes.

    Web of Science

    researchmap

  • Comparative atomic force and scanning electron microscopy for fine structural images of nerve cells 査読

    T Tojima, D Hatakeyama, Y Yamane, K Kawabata, T Ushiki, S Ogura, K Abe, E Ito

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   37 ( 6B )   3855 - 3859   1998年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    Although we can routinely obtain fine structural images of cells by atomic force microscopy (AFM), the adequacy and reliability of morphological information acquired from these AFM images remain to be examined. In this report, we compared images of the line structures of nerve cells as observed by both AFM and scanning electron microscopy (SEM). Although AFM revealed the structure of the top views of cells in greater detail than SEM, their side structures were better observed by SEM. The linear structures in the neural processes detected only by AFM were confirmed, by immunofluorescence staining, to be reflections of the cytoskeletal structures located beneath the cell membrane. These differences between the AFM and the SEM images reflected the characteristics of the detection systems and methods used for sample preparation. Therefore, these results revealed that more detailed information on cell morphology can be obtained by using both AFM and SEM to advantage.

    DOI: 10.1143/JJAP.37.3855

    Web of Science

    CiNii Article

    researchmap

  • Fine surface images that reflect cytoskeletal structures in cultured glial cells by atomic force microscopy 査読

    Y Yamane, D Hatakeyama, T Tojima, K Kawabata, T Ushiki, S Ogura, K Abe, E Ito

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   37 ( 6B )   3849 - 3854   1998年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    The morphology of cultured glial cells was examined using a combination of atomic force microscopy (AFM) and immunofluorescence staining for cytoskeletons. The meshwork of type-1 astrocytes consisted of thick longitudinal and thin lateral lines on the cell surfaces observed by AFM, the former lines were confirmed to be reflections of actin filaments. The astrocytic processes of type-2 astrocytes were observed to be rugged on AFM. These structures were mainly affected by microtubules. Immunofluorescence imaging of microglia revealed that actin filaments and microtubules were arranged radially and wavily along the cell edge, respectively. AFM could detect these radial and wavy structures clearly. These results show that AFM can provide information on the cytoskeletons of glial cells, indicating that AFM is a useful tool for the morphological characterization of cells.

    DOI: 10.1143/JJAP.37.3849

    Web of Science

    CiNii Article

    researchmap

  • Imaging elastic properties of soft materials immersed in water using force modulation mode in atomic force microscopy 査読

    H Haga, S Sasaki, M Morimoto, K Kawabata, E Ito, K Abe, T Sambongi

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   37 ( 6B )   3860 - 3863   1998年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    Using the force modulation mode in atomic force microscopy (AFM), we have succeeded in imaging elastic properties of agar gels immersed in water. The elastic images of ap ar have been captured simultaneously with the topographic images. Stiffer grains of agar whose size is about 200 nm can be clearly seen in the elastic image of 3.0% agar, while they are not so visible in the case of 1.5% agar. These grains probably correspond to aggregation of agar which cannot be observed in the topographic images. We also measured force-versus-distance curves using AFM to confirm that the absolute values of elastic modulus (Young's modulus) of agar coincide with the bulk values measured using the conventional stress-strain method. The estimated values of the elastic moduli with the AFM were 40 and 90 kPa for 1.5% and 3.0% agar gels, respectively. These are in good agreement with the respective bulk values of 30 and 80 kPa obtained using the conventional method.

    DOI: 10.1143/JJAP.37.3860

    Web of Science

    CiNii Article

    researchmap

  • Elastic properties of living fibroblasts as imaged using force modulation mode in atomic force microscopy 査読

    S Sasaki, M Morimoto, H Haga, K Kawabata, E Ito, T Ushiki, K Abe, T Sambongi

    ARCHIVES OF HISTOLOGY AND CYTOLOGY   61 ( 1 )   57 - 63   1998年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:INT SOC HISTOLOGY & CYTOLOGY  

    Using the force modulation mode in atomic force microscopy, we measured elastic properties of living mouse fibroblasts (NIH3T3) in a culture medium, The topographic images of the cellular surface and the corresponding elastic images of the cellular surface were able to be captured simultaneously with high spatial resolution, The consecutive images were useful for examining time-dependent changes in the cellular surface, We observed that some cells continued to shrink and change their softness for 2 hours, Then the force modulation mode in atomic force microscopy shows potential use in analyzing time-dependent regional elastic properties of living cells with high spatial resolution.

    DOI: 10.1679/aohc.61.57

    Web of Science

    PubMed

    CiNii Article

    researchmap

  • Stress induced motion of twin boundary in (TMTSF)(2)PF6 single crystal 査読

    M Mukoujima, T Sambongi, K Kawabata

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   31 ( 3 )   435 - 438   1997年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:KOREAN PHYSICAL SOC  

    Motion of twin boundaries in (TMTSF)(2)PF6 was studied. The twin boundary moves intermittently and chaotically under constant force. Moreover it moves spontaneously in some regions. The spontaneous motion is intermittent and chaotic. Presumably there are other factors, besides external stress and position dependent potential, which determine the motion. The intermittence and chaos are the essentials of twin boundary motion and they can not be explained as long as the twin boundary is regarded as a rigid body.

    Web of Science

    researchmap

  • Effect of substrate temperature on film growth of the organic metal (BEDT-TTF)(2)I-3 査読

    K Kawabata, K Shimotani, T Sambongi

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   31 ( 3 )   431 - 434   1997年9月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:KOREAN PHYSICAL SOC  

    The vacuum evaporation method was modified for thin films of the organic charge-transfer complex (BEDT-TTF)(2)I-3. This modified evaporation method made it possible to investigate the effect of the substrate tempearture on the film properties in detail. The thin films changed systematically from the alpha-phase of (BEDT-TTF)(2)I-3 to the beta-phase as the substrate temperature was raised from 40 degrees C to 60 degrees C. This was caused not by the transformation of the alpha-phase to the alpha(t)-phase but by the growth of two different phases. The morphology and the structure of the deposited films were also examined by atomic force microscopy and X-ray diffraction.

    Web of Science

    researchmap

  • Apparent similarity between motion of twin boundary and spin-density wave sliding wave in Bechgaard salts 査読

    T Sambongi, M Nagasawa, M Mukoujima, K Kawabata

    JOURNAL OF THE KOREAN PHYSICAL SOCIETY   31 ( 1 )   83 - 85   1997年7月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:KOREAN PHYSICAL SOC  

    Response of the spin-density wave condensate in (TMTSF)(2)AsF6 and motion of twin boundaries in (TMTSF)(2)PF6 were studied comparatively. In the former, internal degrees of fredom are essential to understand various dynamical properties. The dynamics of twin boundary is so complicated but it should not be regarded as a rigid planar object.

    Web of Science

    researchmap

  • Practical scan speed in atomic force microscopy for live neurons in a physiological solution 査読

    S Nagayama, T Tojima, M Morimoto, S Sasaki, K Kawabata, T Ushiki, K Abe, E Ito

    JAPANESE JOURNAL OF APPLIED PHYSICS PART 1-REGULAR PAPERS SHORT NOTES & REVIEW PAPERS   36 ( 6B )   3877 - 3880   1997年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:JAPAN J APPLIED PHYSICS  

    We examined the practical scan speed for the observation of live neurons in a physiological solution using atomic force microscopy (AFM) with a desired vertical resolution of the order of 10(-8) mi which was reasonable when taking into account that a flicker of extracellular protein and saccharide on the neurons in the solution occurred during an observation period of a couple of minutes. The practical scan speed was found to be under 40 mu m/s, therefore, if we applied AFM using 100 lines and 100 pixels per line to an observation area of 20 mu m x 20 mu m, the minimum period for acquiring one image was estimated to be about 2 min. This procedure gave us good images that represented the slow three-dimensional dynamics in live neurons, such as the retrograde movement of surface protuberances, but suggested that another approach was required to detect fast structural changes induced by stimulation.

    DOI: 10.1143/JJAP.36.3877

    Web of Science

    CiNii Article

    researchmap

  • Highly conducting 1 : 1 radical cation salt : (DMTSA)X with X=NO3 and BF4 査読

    KAWABATA K, YANAI M, SAMBONGI T, ASO Y, TAKIMIYA K, OTSUBO T

    J. Mol. Cryst. Liq. Cryst   296   197 - 204   1997年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1080/10587259708032321

    Web of Science

    CiNii Article

    researchmap

  • Complex motion of twin boundary in molecular crystal (TMTSF)2PF6 査読

    Complexity and Diversity   108 - 110   1997年

     詳細を見る

  • Twin boundary in Bechgaard salt: Structure and unusual dynamics 査読

    M Mukoujima, K Kawabata, T Sambongi

    JOURNAL DE PHYSIQUE I   6 ( 12 )   1567 - 1574   1996年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:EDITIONS PHYSIQUE  

    Structure and dynamics of twin boundaries in (TMTSF)(2)PF6 were studied. From microscopic observations, they are planar in shape and their width is less than 20 nm. No change in their shape was found. Their movement and pair annihilation do not leave any trace in the crystal surface. Their motion under external force as well as spontaneous movement are intermittent and chaotic. Role of internal degree of freedom is essential.

    DOI: 10.1051/jp1:1996174

    Web of Science

    CiNii Article

    researchmap

  • Twist Morphology of Organic Crystal (BPE-DMB)IBr2 査読

    KAWABATA K, KUMAGAI T, MIZUTANI M, SAMBONGI T

    J. de Phys. I   6 ( 12 )   1575 - 1580   1996年12月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1051/jp1:1996175

    Web of Science

    CiNii Article

    researchmap

  • Electric and Magnetic Properties of new organic Salt (DMTSA)2Cl 査読

    YANAI M, KAWABATA K, SAMBONGI T, ASO Y, TAKIMIYA K, OTSUBO T

    Synthetic Metals   79 ( 2 )   155 - 157   1996年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/0379-6779(96)80184-6

    Web of Science

    researchmap

  • Unusual Motion of Twin Boundary in (TMTSF)2PF6 single Crystal under constant stress 査読

    MUKOUJIMA M, KAWABATA K, SAMBONGI T

    Solid State Commun   98 ( 4 )   283 - 286   1996年4月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/0038-1098(96)00062-2

    Web of Science

    CiNii Article

    researchmap

  • Imaging nerve-terminal structure by atomic force microscopy 査読

    Acta Histochemica et Cytochemica   29   553 - 554   1996年

     詳細を見る

  • AFM obsevation of three dimensional fine structural chage in living neurons 査読

    Bioimages   4   111 - 116   1996年

     詳細を見る

  • Conducting organic complexes using dumbbell-shaped donors (BTFE-DMB) ; X=B, DMtB, DCB 査読

    KAWABATA K, TANAKA K, MIZUTANI M, MORI N

    Synthetic Metals   70 ( 1 )   1141 - 1142   1995年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/0379-6779(94)02791-V

    Scopus

    CiNii Article

    researchmap

  • Synthesis of a novel donor, BETE-DMB, and its properties 査読

    K. Ikeda, K. Kawabata, K. Tanaka, M. Mizutani

    Synthetic Metals   56 ( 1 )   2007 - 2012   1993年3月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A novel donor, 1,4-bis[2-(6,7-ethylenedithio-1,4,5,8-tetrathifulvalen-2-yl)ethenyl]-2,5-dimethylbenzene
    BETE-DMB (1), was synthesized. Its extended π-electron conjugation was confirmed from the electrochemical behaviour. The electrical conductivity of the needle shape single crystals of BETE-DMB/IBr2 is 80 Scm-1 at room temperature, and shows metallic behaviour down to ca. 230 K. © 1993.

    DOI: 10.1016/0379-6779(93)90363-2

    Scopus

    researchmap

  • Peculiar magnetic property of pyrolytic carbon prepared from adamantane 査読

    Kazuyoshi Tanaka, Masahiro Kobashi, Hideki Sanekata, Akira Takata, Tokio Yamabe, Shigeyoshi Mizogami, Kazushige Kawabata, Jun Yamauchi

    Molecular Crystals and Liquid Crystals Science and Technology. Section A. Molecular Crystals and Liquid Crystals   218 ( 1 )   223 - 228   1992年6月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Magnetic-property measurements of pyrolytic carbon prepared by the thermal CVD of adamantane were carried out using the Faraday balance method and the ESR spectroscopy. The content of ferromagnetic metallic oxide as impurity in the samples has been confirmed to be low enough not to influence on the present magnetic-property measurements. Analysis of the measurement results has shown that the sample obtained are basically superparamagnetic and, even, ferromagnetic at low temperatures in a certain sample. © 1992, Taylor &amp
    Francis Group, LLC. All rights reserved.

    DOI: 10.1080/10587259208047044

    Scopus

    researchmap

  • Synthesis of a novel donor, BTFE-DMB, and the electrical properties of its iodine salts 査読

    Makoto Mizutani, Keiji Tanaka, Kiyoshi Ikeda, Kazushige Kawabata

    Synthetic Metals   46 ( 2 )   201 - 205   1992年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    1,4-Bis[2(tetrahiafulvalen-2-yl)ethenyl]-2,5-dimethylbenzene (BTFE-DMB) is synthesized. Both the absolute values of oxidation potentials and the difference between the first and second ones of BTFE-DMB are smaller than those of tetrathiafulvalene (TTF). The resistivity of the single crystal of its iodine salts is as low as 7 × 10-3 ω cm at room temperature. The crystal shows a metallic-conducting behavior above c. 80 K. © 1992.

    DOI: 10.1016/0379-6779(92)90343-H

    Scopus

    researchmap

  • Thin films of (BEDT-TTF) iodide prepared by evaporation method 査読

    K. Kawabata, K. Tanaka, M. Mizutani

    Synthetic Metals   42 ( 1-2 )   2097 - 2100   1991年5月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The effects of evaporation conditions on crystal and physical properties of the evaporated films were investigated from X-ray examination and electric measurement. Conducting (BEDT-TTF) iodide films were obtained under the condition of a short distance between the substrate and the crucible during deposition. As the substrate temperature was raised, the obtained films exhibited various crystal structures having different physical properties. © 1991.

    DOI: 10.1016/0379-6779(91)92025-D

    Scopus

    researchmap

  • Raman spectra of the conductive salt (TTF)18(I3)18(CH2Cl2)2 査読

    Makoto Mizutani, Keiji Tanaka, Kazushige Kawabata

    Synthetic Metals   44 ( 3 )   321 - 325   1991年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Anisotropic Raman spectra of single crystals of (TTF)18(I3)18(CH2Cl2)2 were observed at room temperature. Its anisotropy was reflected on its crystal structure which is composed of three types of segregated stacking columns of TTF molecules. The charge transfer degrees of TTF molecules were estimated from the Raman band frequencies of TTF molecules and structural data of the crystal. © 1991.

    DOI: 10.1016/0379-6779(91)91819-V

    Scopus

    researchmap

  • Pressure-dependence of superconducting transition-temperature and of Hall constant in High-Tc Cu-oxide superconductors

    N. Mori, C. Murayama, H. Takahashi, H. Kaneko, K. Kawabata, Y. Iye, S. Uchida, H. Takagi, Y. Tokura, Y. Kubo, H. Sasakura, K. Yamaya

    Physica C   185   40 - 44   1991年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    researchmap

  • Superconducting thin films of (BEDT-TTF) iodide 査読

    K. Kawabata, K. Tanaka, M. Mizutani

    Synthetic Metals   39 ( 2 )   191 - 194   1990年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Superconducting organic thin films were prepared by using a charge-transfer complex (BEDT-TTF) iodide as a raw material and adopting a novel vacuum evaporation method and heat treatment. X-ray examinations verified that most parts of the obtained film were composed of the αt-phase of (BEDT-TTF)2I3 crystals. Superconducting diamagnetism was observed below about 5 K. © 1990.

    DOI: 10.1016/0379-6779(90)90183-L

    Scopus

    researchmap

  • Ferromagnetism of pyrolytic carbon under low-temperature growth by the CVD method 査読

    K Kawabata, M Mizutani, M Fukuda, S Mizogami

    Synthetic Metals   33 ( 3 )   399 - 402   1989年11月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: 10.1016/0379-6779(89)90485-2

    Scopus

    researchmap

  • Superconductivity of Pb/Si Multilayered Films 査読

    Kazushige Kawabata, Makoto Mizutani, Keiji Tanaka, Kenji Kawasaki

    Japanese Journal of Applied Physics   26 ( 3-2 )   1439 - 1440   1987年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Pb/Si multilayers are prepared by rf sputtering on substrates which are cooled down by liq.N2. Clear modulation of the composition in the multilayers is confirmed by the XPS depth profile examination. The superconducting transition temperatures of the multilayers are almost 7.2K, which is close to the value of bulk Pb. The critical magnetic fields are very large values and exhibit a large anisotropy. © 1987 The Japan Society of Applied Physics.

    DOI: 10.7567/JJAPS.26S3.1439

    Scopus

    researchmap

  • Correlation between superconductivity and Charge-Density Waves in Nb1-xTaxSe3 査読

    K. Kawabata, M. Ido, T. Sambongi,

    J. de Phys.   44   1647 - 1650   1983年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    researchmap

  • Hall Effect and Transverse Conductivities of NbSe3: Evidence for the Sliding Motion of Charge-Density-Wave 査読

    Kazushige Kawabata, Masayuki Ido, Takashi Sambongi

    Journal of the Physical Society of Japan   50 ( 3 )   739 - 740   1981年

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The Hall voltage and conductivities perpendicular to the b-axis of NbSe3 were measured. The former is strongly current-dependent in the non-Ohmic regime, while the transverse conductivities are Ohmic. The results are consistently explained by taking account of the contribution of the sliding charge-density-wave to the conductivity parallel to the b-axis. © 1981, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.

    DOI: 10.1143/JPSJ.50.739

    Scopus

    researchmap

▶ 全件表示

書籍等出版物

  • 細胞の形とうごきIV 細胞の形と細胞骨格

    サイエンス社  2011年 

     詳細を見る

  • Applied Scanning Probe Methods X

    Springer-Verlag  2008年 

     詳細を見る

  • Chromosome Nanoscience and Technology

    TAYLOR & FRANCIS GROUP  2007年 

     詳細を見る

MISC

  • Time dependent static friction force of agar gel-on-glass plate immersed in water 査読

    T Nitta, H Haga, K Kawabata

    JOURNAL DE PHYSIQUE IV   12 ( PR9 )   319 - 320   2002年11月

     詳細を見る

    記述言語:英語   出版者・発行元:E D P SCIENCES  

    We measured the static friction force of agar gel-on-glass plate ill water The static friction force is independent of the apparent contact area between the agar gel and file glass plate. It increases with waiting time, that is, contact duration prior to motion. The static friction force is represented well by a power law of waiting time. The waiting time dependence is different from those of solid-on-solid systems. These results arc discussed, based oil asperity contact model.

    DOI: 10.1051/jp4:20020426

    Web of Science

    researchmap

  • Motion of twin boundary in (TMTSF)(2)X. Comparison with DW dynamics 査読

    T Sambongi, T Yokoyama, T Saga, K Kawabata

    JOURNAL DE PHYSIQUE IV   9 ( P10 )   297 - 298   1999年12月

     詳細を見る

    記述言語:英語   出版者・発行元:E D P SCIENCES  

    Dyanamics of twin boundary mechanically introduced into crystals of (TMTSF)(2)X was studied. Repeated motion of isolated twin boundary was observed under constant external force in the same area was observed with controlled conditions. Effect of various controlling factors as well as of temperature is discussed.

    DOI: 10.1051/jp4:19991077

    Web of Science

    researchmap

  • Activating transcription factor 5 promotes cancer cell invasion through transcriptional activation of integrins 査読

    A. Nukuda, H. Endoh, S. Ishihara, M. Yasuda, T. Mizutani, K. Kawabata, H. Haga

    MOLECULAR BIOLOGY OF THE CELL   26   2015年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Dynamics of Living Cells Measured by Scanning Probe Microscopy

    水谷武臣, 川端和重

    表面科学   34 ( 9 )   500-504 (J-STAGE)   2013年

     詳細を見る

    記述言語:英語  

    DOI: 10.1380/jsssj.34.500

    J-GLOBAL

    researchmap

  • Rac1-, PI3K-, and integrin-beta 1-dependent leader cells that are essential for the collective migration of MDCK cells 査読

    N. Yamaguchi, T. Mizutani, K. Kawabata, H. Haga

    MOLECULAR BIOLOGY OF THE CELL   24   2013年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Involvement of cell polarity and cell migration in folding phenomena of epithelial sheets 査読

    S. Ishida, R. Tanaka, N. Yamaguchi, T. Mizutani, K. Kawabata, H. Haga

    MOLECULAR BIOLOGY OF THE CELL   23   2012年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • EGFR and Integrin alpha 2 beta 1 Dependent Invasiveness of Lung Adenocarcinoma Cells that Survived 10 Gy Ionizing Radiation. 査読

    X. Li, S. Ishihara, M. Yasuda, T. Mizutani, K. Kawabata, T. Nishioka, H. Haga

    MOLECULAR BIOLOGY OF THE CELL   23   2012年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • 細胞骨格・細胞運動・細胞移動 ラミニンを含む軟らかいゲル基質上でみられる上皮細胞集団の3次元形態形成(Cytoskeleton/ Cell motility/ Cell migration 3D Morphogenesis of Epithelial Cells on a Soft Substrate Containing Laminin Induced by Cellular Contractile Force)

    今井 美沙子, 水谷 武臣, 川端 和重, 芳賀 永

    日本細胞生物学会大会講演要旨集   63回   118 - 118   2011年5月

     詳細を見る

    記述言語:英語   出版者・発行元:(一社)日本細胞生物学会  

    researchmap

  • Substrate stiffness regulates NF-kB expression and activity in cancer cells 査読

    S. Ishihara, M. Yasuda, T. Mizutani, K. Kawabata, H. Haga

    MOLECULAR BIOLOGY OF THE CELL   22   2011年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • 3D Morphogenesis of Epithelial Cells on a Laminin-rich Soft Substrate Induced by Cellular Contractile Force 査読

    M. Imai, T. Mizutani, K. Kawabata, H. Haga

    MOLECULAR BIOLOGY OF THE CELL   22   2011年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • 757 粒子法による細胞群の数値シミュレーションの検討(OS21.細胞・生体分子の計算バイオメカニクス(5),オーガナイズドセッション)

    末吉 誠, 胡 長洪, 東藤 貢, 水谷 武臣, 川端 和重

    計算力学講演会講演論文集   2008 ( 21 )   876 - 877   2008年11月

     詳細を見る

    記述言語:日本語   出版者・発行元:一般社団法人日本機械学会  

    粒子法の一種であるMPS法を基本にして、細胞を模擬した膜・繊維・液体からなる複合構造体の計算モデルの構築と、それを用いた群体としての挙動シミュレーションを試みた.その計算モデルの概要と、計算例を示す。

    CiNii Article

    researchmap

  • 走査型プローブ顕微鏡による細胞機能の解析

    水谷武臣, 芳賀永, 加藤幸作, 川端和重

    細胞   40 ( 6 )   250 - 253   2008年6月

     詳細を見る

    記述言語:日本語  

    J-GLOBAL

    researchmap

  • 走査型プローブ顕微鏡を用いた生細胞表面の弾性分布測定

    芳賀 永, 水谷 武臣, 川端 和重

    表面科学 = Journal of The Surface Science Society of Japan   29 ( 4 )   235 - 238   2008年4月

     詳細を見る

    記述言語:日本語   出版者・発行元:日本表面科学会  

    DOI: 10.1380/jsssj.29.235

    CiNii Article

    researchmap

  • Three-dimensional tumor cell movement in collagen gel: mesenchymal-to-amoeboid transition in a sub-clone that survived 10 Gy irradiation

    T. Nishioka, H. Haga, Y. Miyai, M. Yasuda, K. Tsutsumi, R. Yamazaki, H. Shirato, K. Kawabata

    INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS   69 ( 3 )   S148 - S148   2007年

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:ELSEVIER SCIENCE INC  

    Web of Science

    researchmap

  • Wave-like collective movement of epithelial cells on a collagen gel substrate 査読

    Yukiko Ohmori, Hisashi Haga, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   30   60 - 60   2005年6月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Spatial and temporal organization in collective movement of epithelial cells on a collagen gel substrate 査読

    Kanako Hayashi, Hisashi Hag, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   30   60 - 60   2005年6月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Homeostasis of intracellular tension to external deformation regulated by phosphorylation and dephosphorylation of myosin regulatory light chain 査読

    Takeomi Mizutani, Hisashi Haga, Masayuki Takahashi, Yoshikazu Koyama, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   30   110 - 110   2005年6月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Contribution of actin-binding protein filamin a to the spatial and temporal variation of nonmuscle stress fibers 査読

    Kosaku Kato, Hisashi Haga, Kazuyo Ohashi, Tadanao Ito, Thomas P. Stossel, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   30   56 - 56   2005年6月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • 広域走査型プローブ顕微鏡の開発と細胞生物学への応用

    水谷 武臣, 芳賀 永, 川端 和重

    生物物理   45 ( 2 )   105 - 108   2005年3月

     詳細を見る

    記述言語:日本語   出版者・発行元:日本生物物理学会  

    DOI: 10.2142/biophys.45.105

    CiNii Article

    researchmap

  • 細胞のダイナミクスと集団運動(ソフトマターの物理学2004-変形と流動-,研究会報告)

    水谷 武臣, 芳賀 永, 川端 和重

    物性研究   83 ( 3 )   333 - 334   2004年12月

     詳細を見る

    記述言語:日本語   出版者・発行元:物性研究刊行会  

    この論文は国立情報学研究所の電子図書館事業により電子化されました。

    CiNii Article

    researchmap

  • Collective and unidirectional movement of epithelial cells on a collagen gel substrate

    H Haga, K Hayashi, K Kawabata

    MOLECULAR BIOLOGY OF THE CELL   15   179A - 179A   2004年11月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Tensional homeostasis of a single fibroblast regulated by phosphorylation of the myosin regulatory light chain 査読

    M Takeomi, H Haga, M Takahashi, K Kawabata

    MOLECULAR BIOLOGY OF THE CELL   15   159A - 159A   2004年11月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:AMER SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Long-acting changes of cellular stiffness on responding to external stress 査読

    Takeomi Mizutani, Hisashi Haga, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   29   23 - 23   2004年5月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Collective movement of epithelial cells accompanied by rearrangement and decomposition of collagen gel substrate 査読

    O. Kanako Hayashi, Hisashi Haga, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   29   29 - 29   2004年5月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • The role of actin-binding protein filamin a in cell movement and stress fiber formation 査読

    O. Yukiko Ohmori, Hisashi Haga, Tadanao Ito, Kauyo Ohashi, Thomas Stossel, Kazushige Kawabata

    CELL STRUCTURE AND FUNCTION   29   28 - 28   2004年5月

     詳細を見る

    記述言語:英語   掲載種別:研究発表ペーパー・要旨(国際会議)   出版者・発行元:JAPAN SOC CELL BIOLOGY  

    Web of Science

    researchmap

  • Evaluation of Viscoelasticity of Biological Cells in Liquid by Scanning Probe Microscopy 査読

    Yoshio Tanaka, Yoshihiko Hirai, Masaaki Kabuto, Kazushige Kawabata, Hisashi Haga, Masahumi Nagayama

    Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C   67 ( 663 )   3498 - 3504   2001年

     詳細を見る

    記述言語:英語  

    An analytical method is proposed to evaluate the viscoelasticity of a biomaterial in water by the scanning probe microscope. The proposed method utilizes the dependence of amplitude and phase lag of cantilever vibration on the viscoelasticity when the tip on the cantilever cyclically penetrates into the cell. The cyclical penetrations are carried out in two ways
    one is by excitation of the cantilever fixed end, and other by that of the table. The analysis takes the drag force of water due to the cantilever vibration into account. The stiffness and the viscosity of the cell are analytically related with the amplitude and the phase lag of the cantilever vibration. The results shows that the relations among the amplitude, the phase lag, stiffness and viscosity vary significantly depending on the excitation frequencies of the cantilever fixed end and the table. © 2001, The Japan Society of Mechanical Engineers. All rights reserved.

    DOI: 10.1299/kikaic.67.3498

    Scopus

    researchmap

  • Dynamics of isolated twin boundary in organic bechgaard salts crystal and long-time relaxation of its mobility

    K Kawabata, T Yokoyama, M Mukoujima, T Saga, T Sambongi

    SLOW DYNAMICS IN COMPLEX SYSTEMS   469   675 - 676   1999年

     詳細を見る

    記述言語:英語   出版者・発行元:AMER INST PHYSICS  

    Web of Science

    researchmap

▶ 全件表示

受賞

  • ナノプローブテクノロジー賞

    2007年  

     詳細を見る

    受賞国:日本国

    researchmap

  • 2005年日本物理学会誌注目論文

    2005年  

     詳細を見る

  • 2005 Papers of Editors' Choice, Journal of Physical Society of Japan

    2005年  

     詳細を見る

共同研究・競争的資金等の研究

  • 細胞組織形成における細胞運動の協同機構の解明

    研究課題/領域番号:25287106  2013年4月 - 2018年3月

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    川端 和重, 水谷 武臣, 根本 幸児

      詳細を見る

    配分額:18850000円 ( 直接経費:14500000円 、 間接経費:4350000円 )

    生体内で細胞集団は、血管のようなパイプ構造や肺胞のような球殻構造など形態を作り出すことによって特定の機能を生み出している。これらの構造は多細胞の協同性のもとに作り出されるが、協調性の起源についてはこれまで明らかにされていない。本研究では、シスト構造を形成する細胞集団をモデル実験細胞として、細胞運動の解析や細胞が出す力の解析法の開発、特定の遺伝子を欠損させた細胞株の樹立、を通じて、協同性の起源に迫った。更には、細胞や細胞外基質の物理パラメータを用いて、シスト構造の形成に対する数値シミュレーションを行った。

    researchmap

  • 蛍光ライブイメージングを用いた細胞間に発生する力学量測定法の確立

    研究課題/領域番号:23651099  2011年 - 2012年

    日本学術振興会  科学研究費助成事業 挑戦的萌芽研究  挑戦的萌芽研究

    川端 和重, 水谷 武臣

      詳細を見る

    配分額:4030000円 ( 直接経費:3100000円 、 間接経費:930000円 )

    蛍光ライブイメージングと画像解析法により、細胞骨格ならびに細胞間に発生する変形を評価する手法の確立を目指した。この手法は、細胞骨格間の力学相互作用や細胞集団の運動を議論するための足掛かりとなるはずである。

    researchmap

  • 基質の軟らかさによって誘引される細胞の協調的集団運動に関する研究

    研究課題/領域番号:21570158  2009年 - 2011年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    芳賀 永, 川端 和重

      詳細を見る

    配分額:4680000円 ( 直接経費:3600000円 、 間接経費:1080000円 )

    多数の細胞が集団で協調的に運動することは,生体組織の形成や維持など様-な生命現象において重要な役割を果たす.本研究では,細胞集団に自発的な協調運動を誘引させるため,軟らかいコラーゲンゲルを作成し,その上に上皮細胞(MDCK細胞)を培養した.細胞外基質との接着構造を解析し,リーダー細胞の出現機構について調べた.さらに,細胞間に「力」を伝達するセンサーの探索を行った.

    researchmap

  • 細胞骨格のプレハブ再構築仮説の実証

    研究課題/領域番号:21654058  2009年 - 2010年

    日本学術振興会  科学研究費助成事業 挑戦的萌芽研究  挑戦的萌芽研究

    川端 和重, 水谷 武臣

      詳細を見る

    配分額:3000000円 ( 直接経費:3000000円 )

    細胞内における物質輸送は、細胞の巨視的な活動(形態形成や運動など)を考える上で重要な現象である。走査型プローブ顕微鏡(SPM)を用いて、生きた細胞を我々は、既存装置の約500倍の高速(測定時間:数sec/frame)で測定できる生体高速SPM測定法を開発した。この装置を用いて、生きた細胞の骨格形成のダイナミクスを測定し、単粒子追跡解析法によってその運動を解析した。
    その結果、細胞表面で数百nm径のアクチン繊維(F-actin)からなる硬い顆粒が多数生成し、ブラウン運動に似た拡散運動をした。モータータンパク質であるミオシンIIを阻害する薬剤(ブレビスタチン)の投与および温度のわずかな低下によって、顆粒の拡散速度が著しく低下した。よって、顆粒の運動は、アクチンネットワークがモータータンパクによってランダムに張力が働き、その結果、拡散が起こっているといえる。
    この機構が、細胞膜付近の小胞にも起こっているか否かを膜小胞について調べた。小胞に局在するRab5タンパク質を緑色蛍光タンパク質で標識しその運動を調べた結果、単純拡散様の性質は見られなかったものの、熱的な揺動力による細胞骨格線維の曲げ変形の理論と一致する性質を見出した。この性質は、細胞骨格を破壊する試薬を投与することにより大きく乱された。従って、膜小胞の動きには細胞骨格が寄与しているものの、細胞骨格線維の滑り運動ではなく曲げ変形の動力学が支配的に働いていると考えられる。
    細胞膜付近における小胞輸送には、細胞骨格の曲げ変形のダイナミクスが輸送過程を支配している。ここに活性化したミオシンIIが加わると、ミオシンIIが局所的にアクチン線維同士の架橋を破壊しながらアクチン線維を滑らせる。この滑り運動に基づいて新たに単純拡散様の輸送過程が発生し、2つの異なる輸送過程が細胞内で混在すると考えられる。

    researchmap

  • 細胞コロニー内の細胞に個別に蓄積される力学的記憶の解明

    研究課題/領域番号:18340122  2006年 - 2008年

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    川端 和重, 芳賀 永, 根本 幸児

      詳細を見る

    配分額:15940000円 ( 直接経費:13900000円 、 間接経費:2040000円 )

    細胞集団がどのように連携・協同して血管や臓器などのマクロな形態を形成するかその機構を解明することを目的に、細胞に蓄積される力学的記憶効果を調べた。本研究では、走査型プローブ顕微鏡を用いた新たな測定装置を構築し、細胞に力学的変形刺激を加えた場合に細胞内に発生する力の応答を調べた。その結果、細胞の変形パターンによって、その後の細胞の力学的応答が大きく異なり、細胞レベルに力学的な記憶効果があることを明らかにした。

    researchmap

  • 細胞システムにおける「力学平衡」モデルの実証

    研究課題/領域番号:15650051  2003年 - 2004年

    日本学術振興会  科学研究費助成事業 萌芽研究  萌芽研究

    川端 和重, 芳賀 永

      詳細を見る

    配分額:3000000円 ( 直接経費:3000000円 )

    細胞運動や組織形成などには、基質の伸展刺激や流れずり応力等の力学的刺激が重要な働きをすることが知られている。本研究の目的は、外力に対する細胞の力学的応答を調べることにより、細胞内のアクチンフィラメントネットワークの動的性質を明らかにする、特に、外的刺激に対する力学的な平衡状態(張力ホメオスタシス)の存在およびその性質また分子レベルでの要因を明らかにすることである。本研究により得た結果は以下である。
    1)弾性シャーレを用いて、生きたマウス繊維芽細胞(NIH-3T3)を伸長もしくは収縮させた時の、細胞のかたさ分布の時間変化を力学SPMを用いて測定した。細胞内のアクチンストレスファイバーに働く張力にも恒常性が存在し、元の状態に戻るために2時間程度の時定数を持つ。2)ストレスファイバーの収縮力の起源であるミオシン調節軽鎖(MRLC ; Myosin Regulatory Light Chain)に結合したリン酸数と張力の応答の関係を調べた。1リン酸化はできるが2リン酸化することが出来ないMRLC(MRLC-T18A)を過剰に発現させた細胞を機械的に伸張させ、その力学的応答をSPMによって測定した。この細胞では細胞内張力ホメオスタシスは起こらない。3)wild-type細胞を伸長もしくは収縮し、リン酸化されたMRLCの細胞内の空間分布を共焦点蛍光顕微鏡で観察した。細胞の伸長直後にストレスファイバー上に2リン酸化したMRLCが増大し、その後脱リン酸化が進み、120分後には伸長前の状態に戻った。また、細胞を収縮させると、収縮直後に1リン酸化したMRLCが減少し、その後リン酸化が進み、数十分後には収縮前の状態に戻った。2)-3)の結果から、細胞の定常状態におけるMRLCは1リン酸化状態をとり、外部からの伸長によって大きな細胞内張力が必要になれば2リン酸化状態、収縮によって細胞内張力が不要になれば脱リン酸化状態をとると考えられる。すなわち、細胞内張力の安定化機構はMRLCに結合したリン酸の数によって制御されていることが明らかになった。

    researchmap

  • ソフト&ウェット型人工筋肉の創出と生体代替運動システムへの応用

    研究課題/領域番号:14GS0301  2002年 - 2006年

    日本学術振興会  科学研究費助成事業 学術創成研究費  学術創成研究費

    長田 義仁, グン 剣萍, 安田 和則, 八木 駿郎, 山本 眞史, 川端 和重

      詳細を見る

    配分額:686400000円 ( 直接経費:561120000円 、 間接経費:125280000円 )

    (I)ソフト&ウエット人工筋肉となるゲル基本素材の創成
    基本素材とする高分子ゲルにダブルネットワーク-(DN)構造を導入することで、圧縮強度、引張り強度が数メガパスカル(MPa)に達する超高強度ゲルの合成法を発見した。さらに、DNゲルの第一網目における数10nm〜数μmスケールのVoid構造を系統的に変化させることで、ゲルをBrittleからDuctile的な振る舞いまで系統的に制御することに成功した。DuctileのDNゲルがNecking現象を示し、20倍までも伸びることを発見した。この優れたゲル材料を人工関節軟骨へ応用するために、低摩擦性、高強度性を併せ持ったゲルの創製を図り、その結果、破壊強度数十メガパスカル、破壊エネルギーが1000J/cm^2以上、表面摩擦係数10^<-5>〜10^<-4>という従来にないゲルの創成に成功した。
    (II)ゲル基本素材の生体代替運動システムへの応用展開
    (I)で創製したゲルは固体素材では実現不可能な柔軟性と運動性、そして耐衝撃性を併せ持つ。このゲルを人工軟骨、人工半月板に応用するために、その耐摩耗性、生体内耐久性、および生体親和性を評価した。数種類のDNゲルは100万回、走行距離延べ50kmのPinonFlat型摩耗試験で、摩耗率10^<-8>〜10^<-7>mm^3/N・mに達する高い耐摩耗性を示し、これは超高密度ポリエチレン(摩耗率10^<-7>mm^3/N・m)を凌駕する結果であり、ゲルの特性としては驚異的なものである。
    DNゲルのBlock皮下埋め込み試験、ペレット筋内埋め込み試験を行い、数種ゲルの中、PAMPS/PDMAAmゲルが人工軟骨の素材に最も有望であることを明らかにした。さらに、PAMPS/PDMAAmゲル人工軟骨を試作し、関節内埋植試験を行った結果、関節内異物特性は低く、使用した人工軟骨研究用標準動物モデルでは、明らかな有害性は検出されなかった。
    さらに、PAMPS/PDMAAゲル人工軟骨を関節表面から数mmのギャップを作るように埋植すると、この表面である生体内局所(ln situ)に正常関節(硝子)軟骨を自然再生することが出来るという、これまでの世界の常識を覆す発見をした。

    researchmap

  • 生きた動物細胞の粘弾性分布の走査型プローブ顕微鏡による定量的評価法の開発

    研究課題/領域番号:14550222  2002年 - 2003年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    平井 義彦, 川田 博昭, 菊田 久雄, 田中 芳雄, 芳賀 永, 川端 和重

      詳細を見る

    配分額:3600000円 ( 直接経費:3600000円 )

    細胞のマイクロ粘弾性解析手法として,探針をコンタクトモードで走査しながら試料に周期的な応力を加え、たわみ信号に現れる周期的な応答から試料の粘弾性を評価フォースモジュレーション法について,試料の粘弾性と溶液の粘性の両方を考慮に入れたカンチレバーにおける1次元の振動方程式を導入し,この方程式に基づいた数値計算により、カンチレバー振動の振幅・位相から、Hertzモデルを複素弾性率に拡張し、1次元の弾性[N/m]と粘性[Ns/m]から弾性率と粘性係数を計算した。
    次に,走査型プローブ顕微鏡(SPM)のカンチレバー探針を,試料に周期的に押込むときに,特に,探針が試料と接触・乖離を繰返す場合につき、カンチレバー運動に対する流体の抗力を考慮した高次の振動モードを含むカンチレバー運動方程式を解析的に解き,カンチレバー根元の押込み方向励振振動に対するSPMカンチレバー先端の振動振幅比,位相遅れと,試料の表面剛性,表面粘性との関係を導出し,粘弾性分布を定量的に評価する方法を構築した.これより,カンチレバーの位相差,振幅比と,試料の表面粘性,表面剛性の関係を示す粘弾性分布図を求めた.
    これを基にして,生きた細胞の粘弾性特性を測定するためのソフトウエアを開発した.これにもとづき,AFMからの測定データより,生きた細胞の粘弾性分布を測定するシステムの構築と,その有効性を検証した.

    researchmap

  • フィラミンA架橋アクチン系細胞骨格の細胞内動態とその力学応答機能

    研究課題/領域番号:14580695  2002年 - 2003年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    伊藤 忠直, 山崎 昌一, 大橋 一世, 川端 和重

      詳細を見る

    配分額:3600000円 ( 直接経費:3600000円 )

    1.フィラミンA架橋アクチン系細胞骨格の細胞内機能:
    モデル細胞として、メラノーマ由来の株化細胞で、フィラミンの発現をノックアウトしたM2細胞とその発現を回復させたA7細胞を使用した。ガラス基盤上における細胞の増殖・運動状態を位相差顕微鏡により長時間観察した。また、走査型プローブ顕微鏡(SPM)を用いて生細胞の表面形状と硬さを測定し、その後細胞骨格タンパクを固定染色することで表面構造の比較をした。また、細胞の発生する力を比較する目的で、基盤にアクリルアミドゲルを用いて同様の実験を行った。
    (1)細胞表面のかたさを解析した結果、A7細胞のほうが全体的に硬く、細胞全体でかたさに広い分布をもつことがわかった。(2)長時間観察で、A7細胞はM2細胞よりも高い運動能をもつことが明らかになった。一方、細胞分裂には差がなかった。(3)A7細胞は、アクリルアミドゲルに収縮力を働かせたが、M2細胞ではそのようなことがなかった。(4)A7細胞の表面にはアクチンから成るストレスファイバー構造が観察されたが、M2細胞にはほとんど見られなかった。
    以上の結果から、フィラミンAは、ラッフル構造やストレスファイバー構造の形成を通じて、細胞運動および形態維持や力の発生、伝播に必要な細胞の堅さを保つのに必須の役割をしていることが示された
    2.アクチン系細胞骨格のin vitro浸透圧応答:
    アクチン系細胞骨格は、細胞膜を介しての浸透圧差に応答し、細胞の体積を一定に保つ。我々は浸透圧下にあるシステムのエントロピーを定式化することにより、これが「ル・シャトルエの原理」に支配される細胞骨格の新規な機能であることを初めて理論的に明らかにした。

    researchmap

  • 摩擦の物理

    研究課題/領域番号:13894010  2001年

    日本学術振興会  科学研究費助成事業 基盤研究(C)  基盤研究(C)

    松川 宏, 鈴木 勝, 前田 京剛, 川端 和重, 那須野 悟, 三浦 浩治

      詳細を見る

    配分額:3400000円 ( 直接経費:3400000円 )

    内部に多くの自由度を持つ巨視的な系に外力を加えた場合、広義の摩擦を伴う複雑な運動を示すことがある。これに関した現象は固体界面の滑り摩擦から地震、電荷密度波、磁束格子など電子の巨視的凝縮相でのある種の秩序の運動など様々な分野の広いスケールに渡る。本研究では、研究代表者、分担者による周到な準備のもと、8月20〜22日に大阪大学豊中キャンパスにおいて、異なる分野、異なるスケールにわたる広義の摩擦現象に関する実験研究者と理論研究者が集まり、これらの現象を総合的に議論し分野間の交流を深める研究会"摩擦の物理"を開催した。80名ほどの参加者を得て、活発な議論が行われたた。これらの活動を通じて、"摩擦の物理"に関する研究グループが形成され、その後、数回の話しあいを経て、明確な将来の研究計画が立てられた。そして11月には科学研究費補助金特定領域研究"摩擦の物理"の申請へと結実した。この研究組織は総括班と7つの計画研究班からなり、以下のことを目的としている。
    本研究は、現代物性科学・技術の成果をもとに新しい視点から、工学を含めた様々な分野における多様な系・レベルの摩擦機構の研究を有機的に繋げ、ミクロスケールからマクロスケールにわたる現象の階層性を正しく取り込み、摩擦の基礎的機構を統一的に解明する。摩擦の普遍性と個別性を明かにし、物理科学の新しい概念を生み出すとともに、その成果を踏まえた新たな摩擦制御技術の創生を目指す。

    researchmap

  • 強弾性結晶内の孤立ドメイン境界が示す1次元運動における断続性の精密測定

    研究課題/領域番号:11874043  1999年

    日本学術振興会  科学研究費助成事業 萌芽的研究  萌芽的研究

    川端 和重, 三本木 孝

      詳細を見る

    配分額:1700000円 ( 直接経費:1700000円 )

    有機単結晶(TMTSF)_2Xは外力の下で孤立した双晶境界を生じ、その運動がリアルタイムで観察できることを私たちは見いだし、その運動を詳細に調べている。本研究では、特に、この観察から発見した一定応力下における運動の断続性に焦点を当て、その起源を明らかにするために、一旦停止時間の性質を調べた。以下に主な結果を記す。
    1)一旦停止は結晶内に固定された場所において起こる。このため、結晶内の欠陥や転位などの格子系に固定した乱れが起源と考えられる。2)外的条件(応力、温度、待機時間)を一定に制御して繰り返し実験を行うと、一旦停止がおこる直前の局所的速度は一定であるにも関わらず、その直後の停止時間は100倍以上も揺らぐ。局所的な速度が一定であることは、この結晶の外的環境が一定であることを保証していることから、一旦停止の時間は運動とは異なる支配要因によるものであるといえる。すなわち、一旦停止状態は単純に速度の遅い極限状態ではないといえる。3)揺らいだ停止時間の平均植は応力、待機時間とともに速度と同様の依存性を示す。このことから、停止時間は運動状態と同様の外力による影響を受けているといえる。4)停止時間のゆらぎは対数正規分布をしており、その分布関数は応力及ぴ待機時間には依存せず一定であった。
    これらの結果から、結晶内に固定したピンニングセンターにおいて境界は停止し、熱励起によってこのポテンシャルを乗り越えて運動を再開すると考えられる。このピンニングポテンシャルは、境界の反対方向の運動によって平均値の回りに揺らぎ、その結果として停止時間が対数正規分布で揺らぐことが理解できる。ただし、ピンニングポテンシャルの実体および揺らぐメカニズム、およびその揺らぎが外力によって不変である理由については境界に関するミクロな情報を得る研究が必要である。

    researchmap

  • 双晶面のカオス的運動における数値シュミレーションと精密測定

    研究課題/領域番号:08455048  1996年 - 1997年

    日本学術振興会  科学研究費助成事業 基盤研究(B)  基盤研究(B)

    川端 和重, 小野寺 彰, 根本 幸児

      詳細を見る

    配分額:7600000円 ( 直接経費:7600000円 )

    有機単結晶(TMTSF)_2Xに発生した孤立した双晶面は一定の応力下で継続運動を行う。この運動様子を精密に測定し、以下の結果を得た。
    1形態:光学顕微鏡・原子間力顕微鏡および走査型電子顕微鏡の観察により数10nm以下の幅で平面的であり,運動中も光学顕微鏡の精度内で平面的である。2運動全体:一定応力下においても、境界の運動速度は場所によって変化し、場所によっては停止と運動を繰り返すという断続運動を示す。3場所依存性:速度は結晶中の場所ごとに変化する。平均速度で運動の空間依存性は規格化できることから、速度を支配している要因として結晶に固定したピンニングがある。停止と運動は同一運動要因に支配されていると言える。4応力依存性:臨界応力が存在し、臨界応力付近において運動状態にホップ分岐的な断続運動と連続運動の間の移り変わりがある。5待機時間依存性:境界が通過してから再び通過するまでの時間(待機時間)が長くなるほど、同じ応力でも速度は遅くなる。また待機時間を非常に長くした極限では速度は一定値に漸近する。これより、待機時間の間に運動支配する要因に緩和現象が起こっている。結晶内の場所によって待機時間を変えて運動を観測した結果、この緩和は境界自体に起こるのではなく、結晶の各部分で起こっている。6温度依存性:運動速度は温度の上昇に伴って増加する。しかし上昇下降の温度サイクルに対して速度上昇しつづける場合がある。よって単純なポテンシャルを熱的に励起するという現象だけでは理解できない。

    researchmap

  • Cooperative phenomena of living cell systems (Cell migration, Mechanical effects,tissue organization), Friction of the gels (Ageing, Static friction)

      詳細を見る

    資金種別:競争的資金

    researchmap

  • 生命活動における力学的協同現象(細胞運動、細胞集団運動、組織化)、多自由度系におけるマクロスケールにあらわれる複雑な運動の研究(ゲル摩擦)

      詳細を見る

    資金種別:競争的資金

    researchmap

▶ 全件表示