Argüello C, Valenzuela B, Rangel E
Departamento de Patología Experimental, CINVESTAV, IPN, México, DF, México.
Arch Med Res. 1992;23(2):77-80.
The nuclear division of E. histolytica trophozoites was analyzed by using specific stains for DNA, with the aim to define the sequential changes of chromatin during its life cycle. Furthermore, we characterized the internal structural arrangements of microtubules in the microtubular organizing center (MTOC) and determined the number of chromosomes and its association with the spindle. The MTOC is formed by multiple microtubule-nucleating centers, that are involved in the displacement of DNA during nuclear division. We found the existence of a single MTOC in one pole of the nucleus at early anaphase. Our results lead us to propose a new hypothesis in which it is suggested that metaphase corresponds to the arrangement of condensed DNA bodies, or "chromosomes" around the MTOC and, through the assembly of microtubules, one set of uncondensed chromatin is displaced to the opposite pole of the nucleus, while the other remains condensed and associated to the original MTOC. We observed six chromosomes in our preparations, corroborating previous observations (2,3). Whether or not a new MTOC is formed during nuclear division remains to be clarified.
通过使用针对DNA的特异性染色剂分析了溶组织内阿米巴滋养体的核分裂，目的是确定染色质在其生命周期中的连续变化。此外，我们对微管组织中心（MTOC）中微管的内部结构排列进行了表征，并确定了染色体的数量及其与纺锤体的关联。MTOC由多个微管成核中心形成，这些中心在核分裂过程中参与DNA的移位。我们发现在后期早期细胞核的一极存在单个MTOC。我们的结果使我们提出了一个新的假设，即中期对应于浓缩的DNA体或“染色体”围绕MTOC的排列，并且通过微管的组装，一组未浓缩的染色质被移位到细胞核的相对极，而另一组保持浓缩并与原始MTOC相关联。我们在制备物中观察到六条染色体，证实了先前的观察结果（2,3）。在核分裂过程中是否形成新的MTOC仍有待阐明。
