|Budget Amount *help
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2002: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 2001: ¥2,300,000 (Direct Cost: ¥2,300,000)
A living cell is an intelligent chemical system which works dynamically by complex chemical reactions. The objective of the present research is to elucidate the cellular organization in terms of molecular synchronization with the aim to propose a new guideline for manufacturing functionality materials. We use a large amoeboid organism, the plasmodium of the true slime mold Physarum polycephalum, and study mechanisms of (1) organization of time order, (2) optimal design of cell shape, and (3) dynamical synchronization by simulation.
1. Organization of time order
By analyzing a long-term changes in the cell shape, 7 oscillatory components are found, periods ranging from a few secnds to 10h. All other oscillatory phenomena, such as cell cycle, morphogenesis, and periodic streaming of protoplasm, agree with the some one of the 7 periodicity. The following geometric progression holds among the periods Ti : Ti+1/Ti=7.5 and Ti+2/Ti+1=2.8 with I=1,2,3.
2. Optimal design of transportation vein net
When many food-sources were placed at different locations on the uniformly spreading organism, the protoplasm gathers at the food and veins remained from various networks. Geometry of the network is analyzed statistically, and found that the network geometry meets multiple requirements for effective network ; short total length of tubes, close connection (small number of transit food-sites between any two food-sites) and fault-tolerance against an accidental disconnection of tubes.
3. Methematical modeling of the dynamic behavior by the slime mold
The proposed mathematical model is a set of nonlinear partial differential equations which take into account the flow of protoplasm and interaction among chemical oscillations via diffusion and hydrostatic oressure generated by tension generation. This model is successful to simulate typical patterns observed experimentally, as well as the accumulation of attractive locomotion to food-site (favorite site) and mound formation in crowed conditions. Less