研究者データベース

佐藤 勝彦(サトウ カツヒコ)
電子科学研究所
准教授

基本情報

所属

  • 電子科学研究所

職名

  • 准教授

学位

  • 博士(理学)(京都大学)

ホームページURL

J-Global ID

研究キーワード

  • ミクロ相分離   相転移   メンスケール   高分子   粗視化モデル   自己無撞着場理論   ソフトマター   動力学   

研究分野

  • 自然科学一般 / 生物物理、化学物理、ソフトマターの物理

職歴

  • 2014年 独立行政法人理化学研究所 研究員

研究活動情報

論文

  • Katsuhiko Sato, Daiki Umetsu
    Frontiers in Physics 9 2021年07月22日 [査読有り][招待有り]
     
    The vertex model is a useful mathematical model to describe the dynamics of epithelial cell sheets. However, existing vertex models do not distinguish contraction forces on the cell boundary from adhesion between cells, employing a single parameter to express both. In this paper, we introduce the rest length of the cell boundary and its dynamics into the existing vertex model, giving a novel formulation of the model that treats separately the contraction force and the strength of adhesion between cells. We apply this vertex model to the phenomenon of compartment boundary in the fruit fly pupa, recapturing the observation that increasing the strength of adhesion between cells straightens the compartment boundary, even though contraction forces at cell boundaries remain unchanged. We also discuss possibilities of the novel vertex models by considering the stretching of a cell sheet by external forces.
  • Norihiro Iijima, Katsuhiko Sato, Erina Kuranaga, Daiki Umetsu
    Nature Communications 11 1 6320 - 6320 2020年12月 [査読有り]
     
    AbstractMaintaining lineage restriction boundaries in proliferating tissues is vital to animal development. A long-standing thermodynamics theory, the differential adhesion hypothesis, attributes cell sorting phenomena to differentially expressed adhesion molecules. However, the contribution of the differential adhesion system during tissue morphogenesis has been unsubstantiated despite substantial theoretical support. Here, we report that Toll-1, a transmembrane receptor protein, acts as a differentially expressed adhesion molecule that straightens the fluctuating anteroposterior compartment boundary in the abdominal epidermal epithelium of theDrosophilapupa.Toll-1is expressed across the entire posterior compartment under the control of the selector geneengrailedand displays a sharp expression boundary that coincides with the compartment boundary.Toll-1corrects local distortions of the boundary in the absence of cable-like Myosin II enrichment along the boundary. The reinforced adhesion of homotypic cell contacts, together with pulsed cell contraction, achieves a biased vertex sliding action by resisting the separation of homotypic cell contacts in boundary cells. This work reveals a self-organizing system that integrates a differential adhesion system with pulsed contraction of cells to maintain lineage restriction boundaries.
  • Schenz D, Nishigami Y, Sato K, Nakagaki T
    Current opinion in genetics & development 57 78 - 83 2019年08月 [査読有り][通常論文]
  • Okuda S, Kuranaga E, Sato K
    Biophysical journal 116 6 1159 - 1170 2019年03月 [査読有り][通常論文]
     
    Epithelial sheet integrity is robustly maintained during morphogenesis, which is essential to shape organs and embryos. While maintaining the planar monolayer in three-dimensional space, cells dynamically flow via rearranging their connections between each other. However, little is known about how cells maintain the plane sheet integrity in three-dimensional space and provide cell flow in the in-plane sheet. In this study, using a three-dimensional vertex model, we demonstrate that apical junctional fluctuations allow stable cell rearrangements while ensuring monolayer integrity. In addition to the fluctuations, direction-dependent contraction on the apical cell boundaries, which corresponds to forces from adherens junctions, induces cell flow in a definite direction. We compared the kinematic behaviors of this apical-force-driven cell flow with those of typical cell flow that is driven by forces generated on basal regions and revealed the characteristic differences between them. These differences can be used to distinguish the mechanism of epithelial cell flow observed in experiments, i.e., whether it is apical- or basal-force-driven. Our numerical simulations suggest that cells actively generate fluctuations and use them to regulate both epithelial integrity and plasticity during morphogenesis.
  • 折原 宏, 佐藤勝彦
    日本流体力学会 学会誌 「ながれ」 38 4 262 - 269 2019年 [招待有り]
  • モジホコリ
    高木 清二, 佐藤 勝彦, 中垣 俊之
    生物工学 96 8 488 - 492 2018年 [査読無し][招待有り]
  • Katsuhiko Sato
    DEVELOPMENT GROWTH & DIFFERENTIATION 59 5 317 - 328 2017年06月 [査読有り][通常論文]
     
    During early embryonic development, epithelial cells form a monolayer sheet and migrate in a definite direction. This phenomenon, called epithelial cell migration, is an important topic in developmental biology. A characteristic feature of this process is attachment to adjacent cells during migration, which is necessary for maintaining the integrity of the sheet. However, it is unclear how these cohesive cells migrate without breaking their attachments. A mechanism for this phenomenon was recently proposed, in which direction-dependent contraction forces acting on cell boundaries induce unidirectional epithelial migration. In this review, we examine this proposed mechanism from various aspects and provide theoretical background for the collective migration of epithelial cells. This information may be helpful for investigators to realize the basic principles underlying collective epithelial migration and devise new mechanisms for it.
  • Dai Akita, Daniel Schenz, Shigeru Kuroda, Katsuhiko Sato, Kei-ichi Ueda, Toshiyuki Nakagaki
    DEVELOPMENT GROWTH & DIFFERENTIATION 59 5 465 - 470 2017年06月 [査読有り][通常論文]
     
    Vein networks span the whole body of the amoeboid organism in the plasmodial slime mould Physarum polycephalum, and the network topology is rearranged within an hour in response to spatio-temporal variations of the environment. It has been reported that this tube morphogenesis is capable of solving mazes, and a mathematical model, named the current reinforcement rule', was proposed based on the adaptability of the veins. Although it is known that this model works well for reproducing some key characters of the organism's maze-solving behaviour, one important issue is still open: In the real organism, the thick veins tend to trace the shortest possible route by cutting the corners at the turn of corridors, following a center-in-center trajectory, but it has not yet been examined whether this feature also appears in the mathematical model, using corridors of finite width. In this report, we confirm that the mathematical model reproduces the center-in-center trajectory of veins around corners observed in the maze-solving experiment.
  • K. Sato, I. Kunita, Y. Takikawa, D. Takeuchi, Y. Tanaka, T. Nakagaki, H. Orihara
    SOFT MATTER 13 14 2708 - 2716 2017年04月 [査読有り][通常論文]
     
    Shear banding is frequently observed in complex fluids. However, the configuration of macromolecules in solutions undergoing shear banding has not yet been directly observed. In this study, by using the fact that F-actin solutions exhibit shear banding and actin filaments are visualized by fluorescent labels, we directly observed the intrinsic states of an actin solution undergoing shear banding. By combining the 3D imaging of labeled actin filaments and particle image velocimetry (PIV), we obtained orientation distributions of actin filaments in both high and low shear rate regions, whose quantitative differences are indicated. In addition, by using the orientation distributions and applying stress expression for rod-like polymers, we estimated stress tensors in both high and low shear rate regions. This evaluation indicates that different orientation distributions of filamentous macromolecules can exhibit a common shear stress.
  • Dynamic properties of bio-motile systems as a liquid-crystalline structure
    S. Ishiwata, M. Miyazaki, K. Sato, K. Nakagome, S. A. Shintani, F. K, Shimozawa, N. Fukuda, K. Suzuki, J. Takagi, Y. Shimamoto, T. Itabashi
    Mol. Cryst. Liq. Cryst. 647 127 - 150 2017年 [査読有り][招待有り]
  • Experimental models for Murray's law
    D. Akita, I. Kunita, M. D. Fricker, S. Kuroda, K. Sato, T. Nakagaki
    J. Phys. D: Appl. Phys. 50 024001  2017年01月 [査読有り][通常論文]
  • Nakagome K, Sato K, Shintani SA, Ishiwata S
    Biophysics and physicobiology 13 217 - 226 2016年 [査読有り][通常論文]
     
    SPOC (spontaneous oscillatory contraction) is a phenomenon observed in striated muscle under intermediate activation conditions. Recently, we constructed a theoretical model of SPOC for a sarcomere, a unit sarcomere model, which explains the behavior of SPOC at each sarcomere level. We also constructed a single myofibril model, which visco-elastically connects the unit model in series, and explains the behaviors of SPOC at the myofibril level. In the present study, to understand the SPOC properties in a bundle of myofibrils, we extended the single myofibril model to a two-dimensional (2D) model and a three-dimensional (3D) model, in which myofibrils were elastically connected side-by-side through cross-linkers between the Z-lines and M-lines. These 2D and 3D myofibril models could reproduce various patterns of SPOC waves experimentally observed in a 2D sheet and a 3D bundle of myofibrils only by choosing different values of elastic constants of the cross-linkers and the external spring. The results of these 2D and 3D myofibril models provide insight into the SPOC properties of the higher-ordered assembly of myofibrils.
  • Katsuhiko Sato, Tetsuya Hiraiwa, Emi Maekawa, Ayako Isomura, Tatsuo Shibata, Erina Kuranaga
    NATURE COMMUNICATIONS 6 10074  2015年12月 [査読有り][通常論文]
     
    Morphogenetic epithelial movement occurs during embryogenesis and drives complex tissue formation. However, how epithelial cells coordinate their unidirectional movement while maintaining epithelial integrity is unclear. Here we propose a novel mechanism for collective epithelial cell movement based on Drosophila genitalia rotation, in which epithelial tissue rotates clockwise around the genitalia. We found that this cell movement occurs autonomously and requires myosin II. The moving cells exhibit repeated left-right-biased junction remodelling, while maintaining adhesion with their neighbours, in association with a polarized myosin II distribution. Reducing myosinID, known to cause counter-clockwise epithelial-tissue movement, reverses the myosin II distribution. Numerical simulations revealed that a left-right asymmetry in cell intercalation is sufficient to induce unidirectional cellular movement. The cellular movement direction is also associated with planar cell-shape chirality. These findings support a model in which left-right asymmetric cell intercalation within an epithelial sheet drives collective cellular movement in the same direction.
  • Katsuhiko Sato, Shin-ichiro Shima
    PHYSICAL REVIEW E 92 4 042922  2015年10月 [査読有り][通常論文]
     
    We investigate a phase model that includes both locally attractive and globally repulsive coupling in one dimension. This model exhibits nontrivial spatiotemporal patterns that have not been observed in systems that contain only local or global coupling. Depending on the relative strengths of the local and global coupling and on the form of global coupling, the system can show a spatially uniform state (in-phase synchronization), a monotonically increasing state (traveling wave), and three types of oscillations of relative phase difference. One of the oscillations of relative phase difference has the characteristic of being locally unstable but globally attractive. That is, any small perturbation to the periodic orbit in phase space destroys its periodic motion, but after a long time the system returns to the original periodic orbit. This behavior is closely related to the emergence of saddle two-cluster states for global coupling only, which are connected to each other by attractive heteroclinic orbits. The mechanism of occurrence of this type of oscillation is discussed.
  • Katsuhiko Sato, Tetsuya Hiraiwa, Tatsuo Shibata
    PHYSICAL REVIEW LETTERS 115 18 188102  2015年10月 [査読有り][通常論文]
     
    During early development, epithelial cells form a monolayer sheet and migrate in a uniform direction. Here, we address how this collective migration can occur without breaking the cell-to-cell attachments. Repeated contraction and expansion of the cell-to-cell interfaces enables the cells to rearrange their positions autonomously within the sheet. We show that when the interface tension is strengthened in a direction that is tilted from the body axis, cell rearrangements occur in such a way that unidirectional movement is induced. We use a vertex model to demonstrate that such anisotropic tension can generate the unidirectional motion of cell sheets. Our results suggest that cell chirality facilitates collective cell migration during tissue morphogenesis.
  • Jean-Paul Rieu, Helene Delanoe-Ayari, Seiji Takagi, Yoshimi Tanaka, Toshiyuki Nakagaki
    Journal of the Royal Society Interface 12 106 2015年05月 [査読有り][通常論文]
     
    The slime mould Physarum polycephalum is a giant multinucleated cell exhibiting well-known Ca2+-dependent actomyosin contractions of its vein network driving the so-called cytoplasmic shuttle streaming. Its actomyosin network forms both a filamentous cortical layer and large fibrils. In order to understand the role of each structure in the locomotory activity, we performed birefringence observations and traction force microscopy on excised fragments of Physarum. After several hours, these microplasmodia adopt three main morphologies: flat motile amoeba, chain types with round contractile heads connected by tubes and motile hybrid types. Each type exhibits oscillations with a period of about 1.5 min of cell area, traction forces and fibril activity (retardance) when fibrils are present. The amoeboid types show only peripheral forces while the chain types present a never-reported force pattern with contractile rings far from the cell boundary under the spherical heads. Forces are mostly transmitted where the actomyosin cortical layer anchors to the substratum, but fibrils maintain highly invaginated structures and contribute to forces by increasing the length of the anchorage line. Microplasmodia are motile only when there is an asymmetry in the shape and/or the force distribution.
  • Shigeru Kuroda, Itsuki Kunita, Yoshimi Tanaka, Akio Ishiguro, Ryo Kobayashi, Toshiyuki Nakagaki
    JOURNAL OF THE ROYAL SOCIETY INTERFACE 11 95 20140205  2014年06月 [査読有り][通常論文]
     
    Crawling using muscular waves is observed in many species, including planaria, leeches, nemertea, aplysia, snails, chitons, earthworms and maggots. Contraction or extension waves propagate along the antero-posterior axis of the body as the crawler pushes the ground substratum backward. However, the observation that locomotory waves can be directed forward or backward has attracted much attention over the past hundred years. Legged organisms such as centipedes and millipedes exhibit parallel phenomena; leg tips form density waves that propagate backward or forward. Mechanical considerations reveal that leg-density waves play a similar role to locomotory waves in limbless species, and that locomotory waves are used by a mechanism common to both legged and limbless species to achieve crawling. Here, we report that both mode switching of the wave direction and friction control were achieved when backward motion was induced in the laboratory. We show that the many variations of switching in different animals can essentially be classified in two types according to mechanical considerations. We propose that during their evolution, limbless crawlers first moved in a manner similar to walking before legs were obtained. Therefore, legged crawlers might have learned the mechanical mode of movement involved in walking long before obtaining legs.
  • Itsuki Kunita, Katsuhiko Sato, Yoshimi Tanaka, Yoshinori Takikawa, Hiroshi Orihara, Toshiyuki Nakagaki
    生物物理 54 1 S280  一般社団法人 日本生物物理学会 2014年
  • Katsuhiko Sato, Yoshiki Kuramoto, Masako Ohtaki, Yuta Shimamoto, Shin'ichi Ishiwata
    PHYSICAL REVIEW LETTERS 111 10 108104  2013年09月 [査読有り][通常論文]
     
    At an intermediate activation level, striated muscle exhibits autonomous oscillations called SPOC, in which the basic contractile units, sarcomeres, oscillate in length, and various oscillatory patterns such as traveling waves and their disrupted forms appear in a myofibril. Here we show that these patterns are reproduced by mechanically connecting in series the unit model that explains characteristics of SPOC at the single-sarcomere level. We further reduce the connected model to phase equations, revealing that the combination of local and global couplings is crucial to the emergence of these patterns.
  • Itsuki Kunita, Katsuhiko Sato, Yoshimi Tanaka, Yoshinori Takikawa, Hiroshi Orihara, Toshiyuki Nakagaki
    PHYSICAL REVIEW LETTERS 109 24 248303  2012年12月 [査読有り][通常論文]
     
    We report herein the first evidence that an F-actin solution shows shear banding, which is characterized by the spontaneous separation of homogeneous shear flow into two macroscopic domains of different definite shear rates. The constant shear stress observed in the F-actin solution is explained by the banded flow with volume fractions that obey the lever rule. Nonhomogenous reversible flows were observed in the F-actin solution with respect to upward and downward changes in the shear rate. This is the first time shear banding has been observed in a simple biomacromolecule. The biological implications and dynamic aspects of shear flow velocity characteristic patterns are discussed.
  • Daiki Endo, Katsuhiko Sato, Yoshinori Hayakawa
    Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 86 1 016106  2012年07月11日 [査読有り][通常論文]
     
    We performed experiments to investigate slow fracture in thin rubber films under uniaxial tension using high-viscosity oils. In this system we observed an oscillating instability in slowly propagating cracks for small applied strains. The transition between oscillatory and straight patterns occurred near the characteristic strain at which rubber exhibits a nonlinear stress-strain relation. This suggests that nonlinear elasticity plays an important role in the formation of the observed pattern. This was confirmed by numerical simulation for neo-Hookean and linear elasticity models. © 2012 American Physical Society.
  • Yoshimi Tanaka, Kentaro Ito, Toshiyuki Nakagaki, Ryo Kobayashi
    JOURNAL OF THE ROYAL SOCIETY INTERFACE 9 67 222 - 233 2012年02月 [査読有り][通常論文]
     
    Limbless crawling is a fundamental form of biological locomotion adopted by a wide variety of species, including the amoeba, earthworm and snake. An interesting question from a biomechanics perspective is how limbless crawlers control their flexible bodies in order to realize directional migration. In this paper, we discuss the simple but instructive problem of peristalsis-like locomotion driven by elongation-contraction waves that propagate along the body axis, a process frequently observed in slender species such as the earthworm. We show that the basic equation describing this type of locomotion is a linear, one-dimensional diffusion equation with a time-space-dependent diffusion coefficient and a source term, both of which express the biological action that drives the locomotion. A perturbation analysis of the equation reveals that adequate control of friction with the substrate on which locomotion occurs is indispensable in order to translate the internal motion (propagation of the elongation-contraction wave) into directional migration. Both the locomotion speed and its direction (relative to the wave propagation) can be changed by the control of friction. The biological relevance of this mechanism is discussed.
  • Deformation of the equilibrium shape of a vesicle induced by enclosed flexible polymers
    Y. Oya, K. Sato, T. Kawakatsu
    Europhys. Lett. 94 68004  2011年06月 [査読有り][通常論文]
  • Katsuhiko Sato, Masako Ohtaki, Yuta Shimamoto, Shin'ichi Ishiwata
    PROGRESS IN BIOPHYSICS & MOLECULAR BIOLOGY 105 3 199 - 207 2011年05月 [査読有り][通常論文]
     
    It is widely accepted that muscle cells take either force-generating or relaxing state in an all-or-none fashion through the so-called excitation-contraction coupling. On the other hand, the membrane-less contractile apparatus takes the third state, i.e., the auto-oscillation (SPOC) state, at the activation level that is intermediate between full activation and relaxation. Here, to explain the dynamics of all three states of muscle, we construct a novel theoretical model based on the balance of forces not only parallel but also perpendicular to the long axis of myofibrils, taking into account the experimental fact that the spacing of myofilament lattice changes with sarcomere length and upon contraction. This theory presents a phase diagram composed of several states of the contractile apparatus and explains the dynamic behavior of SPOC, e.g., periodical changes in sarcomere length with the saw-tooth waveform. The appropriate selection of the constant of the molecular friction due to the cross-bridge formation can explain the difference in the SPOC periods observed under various activating conditions and in different muscle types, i.e., skeletal and cardiac. The theory also predicts the existence of a weak oscillation state at the boundary between SPOC and relaxation regions in the phase diagram. Thus, the present theory comprehensively explains the characteristics of auto-oscillation and contraction in the contractile system of striated muscle. (C) 2010 Elsevier Ltd. All rights reserved.
  • Yoshimi Tanaka, Toshiyuki Nakagaki
    JOURNAL OF COMPUTATIONAL AND THEORETICAL NANOSCIENCE 8 3 383 - 390 2011年03月 [査読有り][通常論文]
     
    A series of ethological experiments on the primitive unicellular amoeboid organism Physarum polycephalum has shown that it possesses an unexpectedly high ability of information processing. This organism can solve mazes and certain optimization problems, and can demonstrate both anticipatory and contemplative behavior. A number of mathematical models have been proposed to describe and understand this smart behavior. We survey the investigations that have been performed on the cell level.
  • K. Sato, X. -F. Yuan, T. Kawakatsu
    EUROPEAN PHYSICAL JOURNAL E 31 2 135 - 144 2010年02月 [査読有り][通常論文]
     
    Numerous numerical and experimental evidence suggest that shear banding behavior looks like first-order phase transitions. In this paper, we demonstrate that this correspondence is actually established in the so-called non-local diffusive Johnson-Segalman model (the DJS model), a typical mechanical constitutive model that has been widely used for describing shear banding phenomena. In the neighborhood of the critical point, we apply the reduction procedure based on the center manifold theory to the governing equations of the DJS model. As a result, we obtain a time evolution equation of the flow field that is equivalent to the time-dependent Ginzburg-Landau (TDGL) equations for modeling thermodynamic first-order phase transitions. This result, for the first time, provides a mathematical proof that there is an analogy between the mechanical instability and thermodynamic phase transition at least in the vicinity of the critical point of the shear banding of DJS model. Within this framework, we can clearly distinguish the metastable branch in the stress-strain rate curve around the shear banding region from the globally stable branch. A simple extension of this analysis to a class of more general constitutive models is also discussed. Numerical simulations for the original DJS model and the reduced TDGL equation is performed to confirm the range of validity of our reduction theory.
  • Kunihiko Kaneko, Katsuhiko Sato, Tatsuo Michiue, Koji Okabayashi, Kiyoshi Ohnuma, Hiroki Danno, Makoto Asashima
    JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 310B 6 492 - 503 2008年09月 [査読有り][通常論文]
     
    Development is a complex process that involves differentiation into a variety of cell types. In spite of its complexity, the macroscopic pattern and cell types are robust to environmental and developmental perturbations. Even in vitro far from normal developmental conditions, ten normal tissues have been generated from Xenopus animal caps by successive treatment with activin and retinoic acid (RA). To describe both normal development and in vitro organogenesis, we introduce developmental potential following the pioneering Study by Waddington. This potential value represents changeability of a cellular state, which decreases toward a local minimum through development. The attraction to a particular cell type through development is described as a process to decrease the potential value to its local minimum. By choosing an explicit potential form as a function of the concentrations of treated activin and RA, the concentration dependence of in vitro organogenesis is reproduced. The potential landscape is shown to have several local minima, each of which represents a stable cell type. This potential also explains why the induction of given tissues requires more treatment of activin at, later stages. The consequences of the developmental potential hypothesis encompass the robustness of each tissue generation. the loss of competence through development, and the order Of tissues in induction by tissues, which we have confirmed experimentally for in vitro organogenesis. The developmental potential hypothesis for a global description of early development is crucial to understanding the robustness of morphogenesis and explains the achievement of in vitro organogenesis using few molecules as well.
  • Katsuhiko Sato, Kunihiko Kaneko
    PHYSICAL REVIEW E 75 6 061909  2007年06月 [査読有り][通常論文]
     
    An equation describing the evolution of phenotypic distribution is derived using methods developed in statistical physics. The equation is solved by using the singular perturbation method, and assuming that the number of bases in the genetic sequence is large. Applying the equation to the mutation-selection model by Eigen provides the critical mutation rate for the error catastrophe. Phenotypic fluctuation of clones (individuals sharing the same gene) is introduced into this evolution equation. With this formalism, it is found that the critical mutation rate is sometimes increased by the phenotypic fluctuations, i.e., noise can enhance robustness of a fitted state to mutation. Our formalism is systematic and general, while approximations to derive more tractable evolution equations are also discussed.
  • K Sato, K Kaneko
    PHYSICAL BIOLOGY 3 1 74 - 82 2006年03月 [査読有り][通常論文]
     
    Characterizing a cell state by measuring the degree of gene expression as well as its noise has gathered much attention. The distribution of such state values (e.g., abundances of some proteins) over cells has been measured, and is not only a result of intracellular process, but is also influenced by the growth in cell number that depends on the state. By incorporating the growth-death process into the standard Fokker-Planck equation, a nonlinear temporal evolution equation of distribution is derived and then solved by means of eigenfunction expansions. This general formalism is applied to the linear relaxation case. First, when the growth rate of a cell increases linearly with the state value x, the shift of the average x due to the growth effect is shown to be proportional to the variance of x and the relaxation time, similar to the biological fluctuation-response relationship. Second, when there is a threshold value of x for growth, the existence of a critical growth rate, represented again by the variance and the relaxation time, is demonstrated. The relevance of the results to the analysis of biological data on the distribution of cell states, as obtained for example by flow cytometry, is discussed.
  • K Sato, Y Ito, T Yomo, K Kaneko
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 100 24 14086 - 14090 2003年11月 [査読有り][通常論文]
     
    A general relationship between fluctuation and response in a biological system is presented. The fluctuation is given by the variance of some quantity, whereas the response is given as the average change of that quantity for a given parameter change. We propose a relationship where the two are proportional, in a similar way to the fluctuation-dissipation theorem in physics. By studying an evolution experiment where fluorescence of protein in bacteria increases, we confirm our relation by observing a positive correlation between the speed of fluorescence evolution and the phenotypic fluctuation of the fluorescence over clone bacteria. The generality of the relationship as well as its relevance to evolution is discussed.

その他活動・業績

教育活動情報

主要な担当授業

  • ソフトマター物理学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 生命科学院
    キーワード : 弾性体、変形、ひずみ、応力、流体、粘弾性、生物への応用
  • 生物系のための物理学
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 理学部
    キーワード : 力学、電磁気学


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