一种游仆虫无性生殖周期中大核及其DNA含量的变化

应用光学显微镜、显微光度计和定量细胞化学技术研究了一种游仆虫无性生殖周期中大核及其 DNA 含量的变化特征,获得如下结果:(1)游仆虫细胞周期分成 G_1期、S 期和 D 期,各个时期在整个细胞周期中所占的时间速率分别为36%、59%和5%。(2)游仆虫细胞周期中,G_1期大核迅速增大,但此时大核无 DNA 合成现象,DNA 分布密度随大核增大而降低;S 期大核前期增大,此后变小,大核 DNA 含量连续增加,大核 DNA 分布密度也随着增高。8期结束后,大核 DNA 含量相当于 G_1大核的两倍;D期大核又显著增大,DNA 分布密度稍高于 G_1期大核的水平。(3)由游仆虫孚尔根反应大核的形态,大核 DNA 三维吸收图像和显微光度术定量分析数据表明,游仆虫大核 DNA 含量的变化仅发生在 S 期,S 期大核中 DNA 合成与大核改组带相联系。

Changes of Macronucleus Size and Its DNA Content during Asexual Cell Cycle of Euplotes sp.

Studies on the changes of macronucleus size and its DNA content during asexual cell cycle of Euplotes sp.with light microscopy,microphotometry,and quantitative cytochemical techniques.Results as follows:(1) asexual cell cycle of Euplotes sp. might be divided into G_1,S,and D periods.Their relative time ratio are 36%,59% and 5% respectively.(2) In G_1,macronucleus size increases rapidly,with no DNA synthesis.Average density of maoronncleus DNA decreases as macronucleus size increases.During S period,macronucleus size increases first,then decreases;macro- nucleus DNA increases continuously,so is its density.After S period,total amount of macronuoleus DNA is twice as that of G_1.During D period,macronucleus size increases remarkably,macronucleus DNA density is a little higher than that of G_1. (3) With Feulgen reaction to show macronucleus,3 dimensional absorbing graph of maoronucleus DNA,and quantitative microphotometric data,it is clear that macronucleus DNA of Euplotes sp.increases only during S period.Synthesis of macronucleus DNA are related with the appearance of macronuoleus reorganization bands.