介電泳應用於探討胞器－肌動蛋白組合之機械性質

Investigating the dynamics of organelle-actin assembly with dielectrophoresis

李正和(Cheng-Ho Lee)

指導教授 ： 陳恕行

崑山科技大學/工程學院/機械工程研究所/碩士(2007年)

https://doi.org/10.6828/KSU.2007.00033

摘要

在地球環境不斷改變之際，了解生物如何適應新環境是愈來愈受重視的課題。生物適應是從最基本的細胞及分子層級開始。本研究利用介電泳微操控技術來探討胞器－肌動蛋白組合之機械性質，以便了解生物適應機制。
在交流電場中介電泳力可用來研究介電粒子的動力學，細胞膜與胞器膜的雙磷脂膜是介電性的來源。植物細胞中，葉綠體會與肌動蛋白結合，其結合強度由 CHUP (chloroplast unusual positioning) 蛋白控制。CHUP 蛋白是一種與肌動蛋白結合的蛋白(actin-binding protein)。肌動蛋白屬三種細胞骨骼中的一種，肌動蛋白分佈在細胞膜下方。
葉綠體的重定位為植物調適太陽能吸收量的機制，太陽能被植物吸收後只有2至20%真正用於碳的固定化。本研究的實驗方法是將水蘊草葉置於暗室與受光兩種情形，由胞器運動推估肌動蛋白性質。

關鍵字

肌動蛋白 ； CHUP ； 雙磷脂膜 ； 介電泳

並列摘要

Adjustment of biological systems to new environment is a topic attracting increasing attention. It is believed that biological adjustment takes place at cellular and molecular levels. To understand more about biological adjustment, this paper discusses the use of a micro-manipulation tool, dielectrophoresis, to investigation the dynamics of organelle-actin assembly in leaf cells.
Dielectrophoretic forces can be generated in a alternative electric field for studying the dynamics of dielectric particles. The ubiquitous lipid-bilayered membrane of cell and organelles provides the necessary dielectric effect. In plant cells, chloroplasts are positioned by actin, and the positioning is controlled by an actin-binding protein called CHUP. Actin is a type of cytoskeleton concentrated beneath the cell membrane.
Chloroplast reorganization is an important mechanism to adjust the rate of solar energy uptake. Only between 2 and 20% of the light energy absorbed by algae and higher plants is actually used in CO2 fixation. Experiments have been conducted on samples of Egeria densa placed in different lighting conditions. The observed motions will be analyzed with mathematical models for estimating natural frequencies of organelle-actin assemblies.

並列關鍵字

CHUP ； actin ； phospholipid bilayer ； dielectrophoresis

參考文獻

[1] H. Pohl, “The motion and precipitation of suspendsoids in divergent electric fields,” J. Appl. Phys., 22, 1951, pp.869-871.

[2] Oiwa, K., Chaen, S., Kamitsubo, E., Shimmen, T. and Sugi, H. (1990). Steady-state force–velocity relation in the ATP-dependent sliding movement of myosin-coated beads on actin cables in vitro. Proc. Natl. Acad. Sci. USA 87, 7893-7897.

[3] Sugi1 H.and Chaen S., “ Review Force–velocity relationships in actin–myosin interactions causing cytoplasmic streaming in algal cells,” The Journal of Experimental Biology, 2003, 206, pp 1971-1976.

[4] Sakai Y. and Takagi S., “Reorganized actin filaments anchor chloroplasts along the anticlinal walls of Vallisneria epidermal cells under high-intensity blue light”, Planta (2005) 221: pp. 823–830.

[5] Oikawa K, et al, “CHLOROPLAST UNUSUAL POSITIONING1 Is Essential for Proper Chloroplast Positioning,” The Plant Cell, Vol. 15, December 2003, pp 2805–2815,