Rizzoli R, Rizzi E, Falconi M, Galanzi A, Baratta B, Lattanzi G, Vitale M, Mazzotti G, Manzoli L
Istituto di Morfologia Umana Normale, Università di Chieti, Italy.
Chromosoma. 1994 Oct;103(6):393-400. doi: 10.1007/BF00362283.
HeLa metaphase chromosomes were examined by means of "in lens" field emission scanning electron microscopy, which permits high resolution detection of uncoated biological samples. By using uncoated chromosomes as a model for comparison we report evidence of how traditional scanning electron microscopy techniques such as metal coating and conductive methods can generate errors in chromosome structure evaluation, since both give rise to morphological artifacts. By comparing the morphology of uncoated chromosomes obtained by two different isolation procedures, such as that utilized in standard cytogenetics and the polyamine method, we have drawn the following conclusions: (a) the standard cytogenetic method gives rise to a chromosome structure consisting of a flattened network of 10 nm fibers, in which higher order chromatin organization is absent. (b) Chromosomes obtained by the polyamine method show both three-dimensional profile and higher level folding of chromatin fibers, supporting the loop chromosome organization previously suggested by scanning electron microscopy observation of hexylene glycol isolated chromosomes.
利用“透镜内”场发射扫描电子显微镜对HeLa中期染色体进行了检查，该显微镜能够对未镀膜的生物样品进行高分辨率检测。通过使用未镀膜的染色体作为比较模型，我们报告了传统扫描电子显微镜技术（如金属镀膜和导电方法）如何在染色体结构评估中产生误差的证据，因为这两种方法都会产生形态假象。通过比较通过两种不同分离程序获得的未镀膜染色体的形态，如标准细胞遗传学中使用的方法和多胺方法，我们得出了以下结论：（a）标准细胞遗传学方法产生的染色体结构由10纳米纤维的扁平网络组成，其中不存在更高层次的染色质组织。（b）通过多胺方法获得的染色体显示出染色质纤维的三维轮廓和更高层次的折叠，支持了先前通过扫描电子显微镜观察己二醇分离的染色体所提出的环状染色体组织。
