【摘要】 原子力显微术 (atomicforcemicroscopy,AFM)是一种新型的纳米显微技术 ,由于其拥有标本制备简单、分辨率高等优点 ,因此常用于细胞超微结构的观察。双微体 (doubleminutechromosomes ,DMs)是基因扩增的主要表现形式 ,经常出现在肿瘤细胞及耐药细胞中 ,可使肿瘤细胞获得生存优势或产生耐药性 ,因此对双微体进行研究可使人类了解肿瘤的生长特性及其抗药性的产生机理。为寻找一种研究双微体的有效方法 ,本实验利用原子力显微镜对小鼠耐氨甲喋呤细胞 3T3R5 0 0中的双微体进行观察 ,在获得双微体高分辨AFM形态图的同时 ,还对双微体的大小进行了测量 ,发现细胞中双微体大小存在差异。此外 ,就原子力显微镜在双微体研究中的一些技术细节进行了探讨。实验结果表明原子力显微术是研究双微体的一种有效手段。更多还原

【Abstract】 Atomic force microscopy (AFM) has many advantages in the study of biological samples,such as the convenient specimen preparation and the high resolution.In the present study,AFM was used to observe the double minute chromosomes (DMs) in mouse methotrexate resistant cell line 3T3R500.AFM images were obtained by tapping mode,contact mode and later force mode of AFM.DMs were composed of two compact spheres connected with fibers.The number of DMs in the 3T3R500 cells increased with increasing levels of methotrexate (MTX) resistance.The data of the height and the underside diameter of the DMs were also obtained.The details of specimen preparation and scan mode selection of AFM were discussed.Our results show that AFM is a powerful method in the study of DMs.更多还原