2007 Fiscal Year Final Research Report Summary
Emergence of cellular intelligence based on selection of various dynamic pattems
| Project/Area Number |
18500229
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bioinformatics/Life informatics
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| Research Institution | Hokkaido University |
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Principal Investigator |
TAKAGI Seiji Hokkaido University, Research Institute for Electronic Science, Assi. Prof. (80372259)
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| Co-Investigator(Kenkyū-buntansha) |
UEDA Tetsuo Hokkaido University, Research Institute for Electronic Science, Professor (20113524)
NAKAGAKI Toshiyuki Hokkaido University, Research Institute for Electronic Science, Associate Professor (70300887)
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| Project Period (FY) |
2006 – 2007
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| Keywords | True slime mould / Physarum / Oscillation pattern / Rotating spiral wave / Locomotive Mechanism / Contemplative behavior / Reaction-diffusion system / Signal integration |
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| Research Abstract |
1. Recognition of the difference in the fractal dimension of a solid surface by the Physarum plasmodium.
We investigated rhythmic motions of the plasmodium on an area between fractal and smooth surfaces. Initial synchronous oscillation switched to anti-phase oscillation between the parts of the plasmodium on the fractal and smooth surface areas.
2. Emergence of various spatiotemporal patterns of thickness oscillation.
The emergence and transitions of various spatiotemporal patterns of thickness oscillation.
The emergence and transitions of various spatiotemporal patterns of thickness oscillation were studied in the freshly isolated protoplasm of the Physarum plasmodium. New patterns, such as standing waves, chaotic pattern and rotating spirals, developed successively before the well-documented synchronous pattern appeared.
3. Locomotive Mechanism of Physarum Plasmodia
We investigate how an amoeba mechanically moves its own center of gravity using the model organism Physarum plasmodium. Time-
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dependent velocity fields of protoplasmic streaming over the whole plasmodia were measured with a particle image velocimetry program developed for this work. Combining these data with measurements of the simultaneous movements of the plasmodia revealed a simple physical mechanism of locomotion.
4. A new kind of behavior
We found a new kind of behavior that seems to be 'contemplative' in the Physarum plasmodium. The plasmodium migrating in a narrow lane stops moving for a period of time when it encounters the presence of a chemical repellent. After stopping period, the organism suddenly begins to move again in one of three different ways depending on the repellent concentration, namely penetration, splitting into two fronts and turning back. A model based on reaction-diffusion equations, or Gray-Scott model, succeeds to reproduce the experimental observation.
5. Mechanism of signal integration
To investigate the mechanism of intracellular signal integration, stimulus-responses of the plasmodium were studied at the levels of receptor membrane and cell behavior. Signals of attractants and repellents do not interfere at the receptor level, while avoidance response shifts up to 100 times higher repellent concentration as the attractant concentration increases. We proposed a simple molecular mechanism of information integration which can reproduce the experimental results well. Less
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Research Products
(40 results)
