亞精胺影響下DNA構形與DNA碎片分佈之研究Effects; of Spermidine on DNA Conformation and the Distributions of DNA Fragmentation

Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/6966

Title:	亞精胺影響下DNA構形與DNA碎片分佈之研究Effects;of Spermidine on DNA Conformation and the Distributions of DNA Fragmentation
Authors:	賴仕修;Shih-Hsiu Lai
Contributors:	光電科學研究所
Keywords:	DNA 構形;亞精胺;原子力顯微鏡;斷碎;AFM;reentrant;DNA conformation;spermidine;fragmentation
Date:	2007-07-09
Issue Date:	2009-09-22 10:33:27 (UTC+8)
Publisher:	國立中央大學圖書館
Abstract:	本論文研究在凝聚物-亞精胺影響下去氧核醣核酸(DNA)之構形變化。由電泳實驗可知，依據不同的亞精胺濃度，DNA 可分為非凝聚態、凝聚態以及複現態。為了比較此三種狀態下DNA 構形之異同，我們使用原子力顯微鏡(AFM)直接觀測DNA 分子。在非凝聚態下，DNA 呈現花狀結構；而複現態下，DNA 呈現樹枝狀結構。此外，我們藉由DNA 碎片大小之分佈來預測其原始之結構。DNA 斷碎實驗是由DNA 分子與螢光染劑(YOYO-1)接合及亞精胺之影響下，光解作用使之斷碎，再由電泳分析其碎片大小分佈。經由相互比較有或沒有亞精胺影響之碎片分佈，我們發現a) 在亞精胺的影響下，加速DNA 的斷碎過程，b) 在初期的斷碎過程中，有亞精胺影響之斷碎實驗擁有較長DNA 分子的存在，c) 在複現態下，DNA 碎片分佈形式類似於一Lognormal 分佈。由以上的發現，推測高階結構之DNA 分子影響了其斷碎的過程。The conformation of DNA in the presence of condensing agent, spermidine is studied. The non-condensed, condensed, and reentrant states of DNA in different concentrations of spermidine are determined by the gel electrophoresis. The goal of this study is to compare the conformations of DNA in these three states. The atomic force microscope (AFM) is used to probe the DNA directly. The flower-shaped and the branch-like structures of DNA are observed in the non-condensed and the reentrant state, respectively. We also estimate the structure of DNA from the distributions of the DNA fragments.The light induced fragmentation of DNA in the presence of fluorescent dye, YOYO-1 and spermidine is analyzed by the gel electrophoresis. By the comparison of the distributions in the presence and absence of spermidine, it is found that a) spermidine enhances the fragmentation process, and b) in the presence of spermidine, the existence of the longer DNA fragments is observed during the early fragmentation process, and c) the form of the distribution of DNA fragments in the reentrant state is similar to the Lognormal distribution. These findings suggest that the higher order structures of DNA molecules are involved in the fragmentation process.
Appears in Collections:	[Graduate Institute of Optics and Photonics] Electronic Thesis & Dissertation

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