黏菌之運動模型研究; An experimental study of the motility of slime mold

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/7507

Title:	黏菌之運動模型研究;An experimental study of the motility of slime mold
Authors:	徐殊凡;Shu-Fan Hsu
Contributors:	物理研究所
Keywords:	黏菌;Dictyostelium discoideum
Date:	2007-07-16
Issue Date:	2009-09-22 10:59:04 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本研究是用影像處理的技術來分析黏菌的運動，藉由追蹤每個黏菌的位置，計算黏菌的運動性。發現黏菌的行為符合 <R2 (t)>= 4D(t-t(1-exp (-t/t)))， t : persistence time，D: modify diffusion constant，若與布朗運動 <R2>= 4Dt 做比較，表示黏菌似乎是有記憶性行為的，在不同密度下t和D隨著時間有所不同變化。另外,也研究黏菌在不同密度與不同cAMP濃度下的聚集行為。發現黏菌在高密度走得越快，不同密度的黏菌，聚集的時間呈現power law的形式，且速度隨時間的變化也有所不同，而聚集前有升高的趨勢。黏菌的速率分佈與高斯分佈是非常近似的，而且是可藉由V2max 來scale。另外。當不同濃度的化學趨向性物質cAMP加入agar中，黏菌的聚集行為也跟著受影響，在cAMP大於10-6M，少量的黏菌就聚集。 The motion of Dictyostelium discoideum (DD) is analyzed by digital image processing. Cells motilities are calculated by tracking the positions of the cells. The movement of cells can be put into the form <R2 (t)>= 4D(t-t(1-exp (-t/t))) where t* is the persistence time and D* is the modified diffusion constant. Compared with Brownian motion <R2>= 4Dt, cells seems to have a temporary memory. The parameters t* and D* are functions of time and plating densities. Cell motions in different plating densities and different cAMP (a chemo-attractant for DD) concentrates are also studied. The aggregation time of DD is found to be in the form of a power law with plating density. In high densities, cells aggregate faster than in low densities. Cell velocity varies with time and becomes higher when cells aggregate. Cells velocity distribution is approximately Gaussian and they can be scaled by V2max. Besides, cells plated on agar with different concentration of cAMP show different types of aggregation. Cells seems to aggregate with smaller clusters when the cAMP concentration is higher than 10-6M.
Appears in Collections:	[Graduate Institute of Physics] Electronic Thesis & Dissertation

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