中华大蟾蜍染色体“单位线”结构的研究

适量BrdU处理中华大蟾蜍外周血淋巴细胞,常规制片后可观察到直径恒定为0.4μm的染色质纤维——单位线结构。本实验表明两栖类染色体同样具有单位线结构,并发现组成染色体两单体的姐妹单位线相伴排列,且与中期染色体有明显的形态联系。通过分析显示染色体和单位线过渡变化的分裂相,认为染色体高级结构由单位线进一步螺旋化完成,从而支持Bak模型。

STUDIES ON THE UNIT FIBER STRUCTURE OF THE CHROMOSOME OF THE BUFO BUFO GARGARIZANS

When added in a proper concentration to lymphoid cells of Bufo bufo gargarizans, BrdU induces the forms of some chromatin fibers which are 0.4 um in diameter. This paper demonstrates their properties by Feulgen stain and DAPI stain, and calls them "unit fibers". The unit fibers exist in different ways:l. All chromatin of a cell exists in unit fiber form; 2. Unit fibers and chromosomes exist in the same karyotypc and unit fibers connect remarkable with metaphase chromosomes. The interesting fact is that two unit fibers forming one chromosome exist parallely, which was named "sister unit fibers". Through analysing of the transitional metaphase karyotypes which show the transition from unit fiber to chromatid, we suggest that the unit fiber is a general structure of the eukaryotic chromosome and the high order structure of the chromosome is completed by spirality of the unit fibers. This paper also discusses the character of unit fiber in the cell cycle, which shows that the late G2 phase is very important to induce the unit fibers.