扫描电镜观察人体中期染色体非显带和G显带的表面亚显微结构

ABSTRACT(Partial)SCANNING ELECTRON MICROSCOPIC OBSERVATION ON THE SURFACE SUBMICROSCOPIC STRUCTURE OF NON-BANDED AND G-BANDED ON HUMAN METAPHASE CHROMONOSOMES

摘要:

应用 LM(光镜)与 SEM(扫描电镜)观察同一病例非显带和不同程度 G 显带的人体中期染色体,证明染色体固有的大体形态相同,而表面结构有显著的差异。在 LM下,染色体呈扁平状,未见表面的亚显微结构。而在 SEM 下,染色体是圆柱体状,非显带染色体表面有绒毛状和不规则的锯齿状突起,偶见纤维。G 显带染色体出现隆起带区(阳性带区)和凹陷带区(阴性带区),与 LM 显示的带型相符合。在高倍下,各臂的带区内有许多纤维并向周围伸展,在某些带区内有圆形小突起,体现了染色体的纤维结构。掌握 G 显带的变化特征对于在 SEM 下识别各号染色体和选择优质带型有重要意义。在协助临床鉴别染色体异常区带部位有实际价值。

Abstract:

Observing the non-banded and G-banded human metaphase chrom- somes of the same patient by the LM and the SEM,It was evident that chromosomes specific gross morphology was the same.In the LM,chromosomes were flat and submicroscopic structure had not found.But in the SEM,chromosomes were of three-dimensional cylindrical profile,with well-defined chromati- ds.Non-banded chromosomes surface had villose morphology and irregular indentation along the chromatids,Occasionally observable fibers.Swelled regions(Positive G-bands)and invaginated regions (Negative G-bands or interband regions)appeared in G-banded chromosomes.This phenomenon corresponded to G-bands in the LM. In the SEM at higher magnification,a number of fibers appe- ared in the chromosome bands and these fibers expanded beyond the chomosome boundary.In some areas the rounded projections were observed.It was evident that the earlly stages of G-bandi- ng revealed the folded fiber model of chromosome structure. To understand the specificity structure modification of G-bands provide a reliable means of chromosome identification and find olear G-bands,is of considerable value to identify chromosome abnormal regions in clinical diagnosis.