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High resolution imaging analysis of elements and molecules in a cell with an X-ray contact microscope.

使用 X 射线接触显微镜对细胞中的元素和分子进行高分辨率成像分析。

基本信息

批准号：
07508001
负责人：
SHINOHARA Kunio
金额：
$ 21.63万
依托单位：
University of Tokyo (1996-1997)Tokyo Metropolitan Organization for Medical Research (1995)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1997
项目状态：
已结题

项目摘要

X-ray contact spectromicroscopy has been developed for the study of molecular and elemental distribution in biological specimens based on X-ray absorption characteristics. The system consists of a spectroscopy section for XANES measurements of biomolecules and an imaging section of a contact microscopy of dried specimens. An electronic zooming tube, a major component of the imaging section, has been improved in handling of specimens and in the operation of electromagnetic coils. The performance of the system was evaluated using synchrotron radiation at the Photon Factory, KEK,Tsukuba, Japan. Using a test pattern with defined line spacings at least 0.5um was resolved. The efficiency of photon detection was estimated as about 1% mainly due to the photoelectron yield of gold photocathode. With this system we have studied the elemental distribution of carbon, nitrogen, oxygen, calcium and iron in a human HeLa cell with the development of computer program using the least square method. At the spectroscopy section XANES profiles of biomolecules such as nucleic acids, proteins, and sugar were surveyed over the absorption edges of constituent elements to explore molecular specific resonance peaks which are available to molecular imaging in a cell. Resonance peaks at the phosphorus K-absorption edge and at the nitrogen K-absorption edge were found to be useful for imaging DNA related molecules in a cell. The dense structure in a nuclear area of mitotic HeLa cell has been detected by the subtraction between images on the peak wavelength of the resonance peak and below the peak wavelength, suggesting the image of DNA related molecules such as chromosomes.

X射线接触光谱显微术是根据X射线吸收特性研究生物样品中分子和元素分布的一种新技术。该系统包括一个光谱部分的XANES测量的生物分子和干燥标本的接触显微镜的成像部分。电子变焦管，成像部分的主要组成部分，已被改进，在处理标本和电磁线圈的操作。该系统的性能进行了评价，使用同步辐射的光子工厂，KEK，筑波，日本。使用具有定义的线间距的测试图案，分辨至少0.5um。光子探测效率估计约为1%，主要是由于金光电阴极的光电子产额。利用该系统，我们研究了人HeLa细胞中碳、氮、氧、钙和铁的元素分布，并用最小二乘法编制了计算机程序。在光谱部分，在组成元素的吸收边缘上调查了生物分子如核酸、蛋白质和糖的XANES谱，以探索可用于细胞中分子成像的分子特异性共振峰。发现在磷K-吸收边缘和氮K-吸收边缘处的共振峰对于成像细胞中的DNA相关分子是有用的。通过在共振峰的峰值波长上和峰值波长之下的图像之间的相减，检测到有丝分裂的HeLa细胞的核区域中的致密结构，提示了DNA相关分子如染色体的图像。