When two types of clonal cell populations competitively grow in epithelial tissues, only at the boundary between the two clones, apoptosis selectively occurs in the cells with lower division rate. Although genetic studies have suggested that F-actin dependent mechanical force is a major regulator of cell competition, how the difference of division rates affects the mechanical force is little investigated. Using the cell vertex model, we numerically found that the boundary of the clones was more

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... smoothly rounded only as the difference of division rates increases. This boundary shape is consistent with experiments in Drosophila. Moreover, the slower dividing cells exhibited boundary-specific abnormalities not only in cell shape, but also in tensile force. 3P273 ENaC 細胞内動態の数理モデル構築による上皮 Na + 輸送制御 解析 Epithelial Na + channels (ENaC) are translocated to the apical cell membrane from the intracellular store site. Experimental observations on ENaC-mediated Na + transport indicate that at least following 4 steps are involved in ENaC translocation: i.e. 1) insertion, 2) endocytosis, 3) recycling, and 4) degradation. To understand more details about regulation of Na + transport in epithelial cells and which state is the rate-limiting one, we applied a mathematical model including 4 steps for electrophysiological parameter of Na + transport, suggesting that the amount of recycled ENaCs depends on quality control of ENaC in the intracellular store site. This means that this model leads us to novel understandings on ENaC-mediated Na + transport. 3P274 真性粘菌 Physarum polycephalum とそのモデルによる錯視の 計算 Computing visual illusion by Physarum plasmodium and the model True slime mold Physarum polycephalum plasmodium is a huge unicellular amebic organism. It is widely used in biocomputing studies. However, the most of these studies used plasmodium as optimization calculator. By contrast, we propose Physarum biosensor element that duplicate human KANSEI/feeling information. We show Physarum plasmodium and our asynchronous cellular automata model are able to "calculate" visual illusions such as subjective contour of Kanizsa's triangle and Muller-Lyer illusion. 3P275 錯視を引き起こす図形パターンに対する真性粘菌変形体の 反応 Behavior of the physarum plasmodium to the graphical pattern that provide the optical illusion The plasmodium of Physarum polycephalum is a giant acellular organism that crawls on planar surfaces foraging food sources and forms a network of protoplasmic tubes connecting the masses of protoplasm at the food sources. In this study, we investigated the behavior of the plasmodium to the graphical food sources arranged in the pattern that provide the optical illusion Kanizsa triangle. We found that such graphical patterns have an effect on the plasmodium same as optical illusion in terms of connecting tube network between food sources. Moreover, in this experiments, we introduced the epochal material of food source made from nutrient rich agar, which is easily-shaped into various figures and sizes. 3P276 概日中枢時計のウエーブパターンとその機能について Wave-like structure and its function in the circadian master clock Hiroshi Kori 1,2 ( 1 Ochanomizu Univ, 2 CREST) Modeling and Analysis of circadian rhythm In this presentation, I will present our recent mathematical studies, in collaboration with experimentalists, on the wave-like structure and its function in the circadian master clock. 3P277 Dependence of cell differentiation ratio on cell-cell interaction and noise Fumiko Ogushi, Hiroshi Kori (Ochanomize University) Differentiation is one of the most fundamental ability of biological cells and cell differentiation is considered to be controlled by the expression level of certain genes. Recent experimental studies indicate that cell-cell interaction plays an important role in cell-fate decision. To understand the control mechanisms of cell differentiation, we introduce a simple multiplecell model. In this presentation, we report the effect of interaction and noise on cell differentiation ratio. -S257 -Poster, Day 3