Seibutsu Butsuri
Online ISSN : 1347-4219
Print ISSN : 0582-4052
ISSN-L : 0582-4052
Volume 20, Issue 2
Displaying 1-5 of 5 articles from this issue
  • Hiroshi SHIMIZU, Yoko YAMAGUCHI
    1980 Volume 20 Issue 2 Pages 61-74
    Published: March 25, 1980
    Released on J-STAGE: May 25, 2009
    JOURNAL FREE ACCESS
    Life phenomena are a kind of ordered dynamics appearing in macroscopic systems, living systems. Schrödinger has proposed a molecular mechanism for the organization of life phenomena, i.e., an 'order-from-order' mechanism where ordered dynamics are composed of ordered molecular dynamics, much as the ordered dynamics of a watch is caused by orderly movements of its mechanical elements. In this paper we verify from studies on artificial active streamings in a streaming system reconstituted from rabbit skeletal F-actin and heavy meromyosin that one life phenomenon, active streaming, is caused by the 'orderfrom-order' mechanism. This will be also the case for muscle contraction. Moreover, it is probable that this mechanism generally works in biological motilities. We also clarify that dynamic cooperativity among molecules gives rise to order in molecular dynamics. Hence, dynamic cooperativity is the key mechanism for life phenomena caused by the 'order-from-order' principle at the subcellular level. To produce dynamic cooperativity it is necessary for component molecules or elements to have three states, i.e., inactive (stable) state 0, energized or energy-storing (quasi-stable) state 1, and active (unstable) state 2. Each molecule performs the elementary cycle 0→1→2→0 repeatedly by using free energy at the molecular level. In a state far from thermodynamic equilibrium, dynamic cooperativity is yielded in 2→0 due to a kind of triggering action of neighborillg elements and breaks the thermodynamic detailed balance. In addition, dynamic cooperativity gives component molecules long-range correlations which depend on the structure of organelles or molecular assemblies. Dynamic cooperativity will give a high efficiency in chemomechanical conversions.
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  • Akinori SARAI, Sigeo YOMOSA
    1980 Volume 20 Issue 2 Pages 75-83
    Published: March 25, 1980
    Released on J-STAGE: May 25, 2009
    JOURNAL FREE ACCESS
    Excitation and electron transfer are important elementary processes in photosynthetic energy conversion. Recent developments in experimental techniques, such as laser photolysis and purification of protein complex from membrane systems, enable us to discuss these processes at the microscopic level.
    This review summarizes the recent experimental and theoretical developments in this field and discusses the present problems and future prospects.
    In particular, we discuss the following topics in detail: (1) The Theory of photosynthetic excitation transfer, and how it can explain the ultrafastness and high efficiency of this process. The temperature dependence of the excitation transfer and its correlation with these properties. (2) Nonlinear phenomena in the photosynthetic excitation transfer and their significance in understanding the topology of the photosynthetic unit. (3) The quantum-mechanics of photosynthetic electron transfer and its use to explain the temperature dependence of the transfer rate. Possible explanations of the ultrafastness, high efficiency and irreversibility of the primary electron transfers around the reaction center.
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  • Kokichi TANAKA
    1980 Volume 20 Issue 2 Pages 84-93
    Published: March 25, 1980
    Released on J-STAGE: May 25, 2009
    JOURNAL FREE ACCESS
    This article is an introductory overview on artificial intelligence and its applications.
    The first section explains artificial intelligence and presents a bibliographical survey of related research and development works.
    The following section contains a brief review on some research topics together with perspectives obtained from a methodological view point.
    Lastly, some interesting and practical applications of artificial intelligence are illustrated along with the works of the present author.
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  • Hidenosuke Nishio
    1980 Volume 20 Issue 2 Pages 94-98
    Published: March 25, 1980
    Released on J-STAGE: May 25, 2009
    JOURNAL FREE ACCESS
    In the classical embryology, cell lineage was a descriptive tool for cleaving eggs. Recently a complete lineage has been established for early and post-embryonic development of the nematode C. elegans. Considering the constancy of lineage from animal to animal, we here propose the hypothesis that the cellular division time and interaction are determined by the division history of each cell. With this hypothesis, we discuss theoretically the cell proliferation process and propose an automaton model of the developmental process, which is idealized as a series of abstract directed labelled graphs.
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  • 1980 Volume 20 Issue 2 Pages 99-109
    Published: March 25, 1980
    Released on J-STAGE: May 25, 2009
    JOURNAL FREE ACCESS
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