Research Institute for Electronic Science, Hokkaido University, Sapporo 060-0812, Japan
(Received November 4, 1998; Accepted December 3, 1998)
Keywords: True Slime Mold, Physarum Plasmodium, Cell Behavior, Morphogenesis, Oscillation
Abstract. The mechanisms of how a large amoeboid cell of the Physarum plasmodium determines its own size and shape are discussed in terms of pattern dynamics. Environment-dependent shape of the plasmodium is considered in relation to bio-computing. Chemical basis for the global cell shape is shown to be chemical patterns self-organized within the cell which are resulted from coupled oscillatory chemical reactions. Information judgment and global control of the protoplasmic streaming are shown to be related to pattern dynamics among coupled oscillators. A new morphogenetic phenomenon of self-breaking of the plasmodium is discussed in relation to the control of cell size. Also the large rhythmic contraction, an element of information processing, is shown to emerge only when the organism attains a certain critical size. All these phenomena indicate that the large amoeboid cell is organized dynamically and hierarchically.