A comparison between hollow cone illumination and wavelet transform methods for chromatin fiber orientation measurement

IF 2.2 3区工程技术 Q1 MICROSCOPY

Micron Pub Date : 2025-05-20 DOI:10.1016/j.micron.2025.103859

Misa Hayashida , Rinyaporn Phengchat , Marek Malac , Keiko Shimada , Shigeo Mori , Yoshio Takahashi , Ken Harada

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引用次数: 0

Abstract

Nucleosomes are proven to be the fundamental unit of chromosome structure. The stacking and folding of the nucleosome fibers within a chromosome is not fully understood. One of the reasons for the incomplete understanding of chromosome internal structure is that a nucleosome, about 11 nm in diameter, can not be resolved within the large chromatids (∼ 700 nm diameter) of a chromosome. In a transmission electron microscope (TEM), the large difference in size between the small diameter nucleosomes and a chromosome results in an extremely low contrast arising from individual nucleosomes. Consequently, the nucleosome fiber can not be detected within an intact chromosome. In this study, we compared two different methods in TEM, namely the hollow cone illumination (HCI) TEM and wavelet transform (WT) analysis on bright-field TEM (BFTEM) images, to analyze internal structure of chromosomes at length scales ranging from 10 to 30 nm. Isolated chromosomes were expanded and the orientation of the chromatin fibers was measured by HCI TEM and by WT applied to BFTEM. We demonstrated that the results obtained by the two methods are in an agreement.

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空心锥照明与小波变换在染色质纤维取向测量中的比较

核小体被证明是染色体结构的基本单位。染色体内核小体纤维的堆叠和折叠尚不完全清楚。染色体内部结构不完整的原因之一是，核小体（直径约11 nm）不能在染色体的大染色单体（直径约700 nm）内被分解。在透射电子显微镜（TEM）下，小直径核小体和染色体之间的巨大尺寸差异导致单个核小体产生极低的对比度。因此，核小体纤维不能在完整的染色体中被检测到。在这项研究中，我们比较了两种不同的透射电镜方法，即空心锥照明（HCI）透射电镜和小波变换（WT）分析的亮场透射电镜（BFTEM）图像，分析染色体的内部结构在10至30 nm的长度尺度。将分离的染色体进行扩增，用HCI透射电镜和应用于BFTEM的WT测量染色质纤维的取向。我们证明了两种方法得到的结果是一致的。

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来源期刊

Micron 工程技术-显微镜技术

CiteScore

4.30

自引率

4.20%

发文量

100

审稿时长

31 days

期刊介绍： Micron is an interdisciplinary forum for all work that involves new applications of microscopy or where advanced microscopy plays a central role. The journal will publish on the design, methods, application, practice or theory of microscopy and microanalysis, including reports on optical, electron-beam, X-ray microtomography, and scanning-probe systems. It also aims at the regular publication of review papers, short communications, as well as thematic issues on contemporary developments in microscopy and microanalysis. The journal embraces original research in which microscopy has contributed significantly to knowledge in biology, life science, nanoscience and nanotechnology, materials science and engineering.