Horinouchi Yusuke, Togashi Tatsuya
Marine Biosystems Research Center, Chiba University, Kamogawa, 299-5502, Japan.
Bot Stud. 2019 Jun 20;60(1):8. doi: 10.1186/s40529-019-0256-z.
Some marine algae exhibit several characteristics of mitosis (e.g., the timing of mitosis such as diurnal periodicity) that are unique from those of land plants. Not only the timing but also other characteristics of mitosis, including the process itself and the number of chromosomes involved, are largely unknown in ulvophycean marine green algae. Effective mitotic inhibitors are useful for observing mitosis and identifying the number of chromosomes. However, few such inhibitors are available for ulvophycean algae. Here, we examined the timing and process of mitosis and the number of chromosomes with several mitotic inhibitors in the haploid gametophyte cells of the Ulvophyceae alga Monostroma angicava.
Mitosis did not occur during the light period but began immediately after the onset of the dark period. The typical process of mitosis was observed. The mitotic inhibitors colchicine and 8-hydroxyquinoline, which generally arrest mitosis in land plants, were ineffective in M. angicava. We found that three other mitotic inhibitors, amiprophos methyl, griseofulvin and oryzalin, are effective to arrest mitosis. With three-dimensional fluorescence microscopy, we demonstrated that there were nine chromosomes in each cell.
In the gametophyte cells of M. angicava, mitosis occurs diurnally. It is triggered by the onset of the dark period. We identified the number of chromosomes as N = 9. Our study shows effective inhibitors to observe mitosis in ulvophycean algae.
一些海藻表现出有丝分裂的几个特征（例如，有丝分裂的时间，如昼夜周期性），这些特征与陆地植物不同。不仅有丝分裂的时间，而且有丝分裂的其他特征，包括过程本身和涉及的染色体数量，在石莼目海洋绿藻中很大程度上是未知的。有效的有丝分裂抑制剂对于观察有丝分裂和确定染色体数量很有用。然而，很少有这样的抑制剂可用于石莼目藻类。在这里，我们用几种有丝分裂抑制剂研究了石莼目藻类角叉菜单条紫菜单倍体配子体细胞中有丝分裂的时间、过程和染色体数量。
有丝分裂在光照期间不发生，但在黑暗期开始后立即开始。观察到了典型的有丝分裂过程。通常使陆地植物有丝分裂停滞的有丝分裂抑制剂秋水仙碱和8-羟基喹啉对角叉菜无效。我们发现另外三种有丝分裂抑制剂，甲基胺草磷、灰黄霉素和氨磺乐灵，对阻止有丝分裂有效。通过三维荧光显微镜，我们证明每个细胞中有九条染色体。
在角叉菜的配子体细胞中，有丝分裂每天发生一次。它由黑暗期的开始触发。我们确定染色体数量为N = 9。我们的研究表明了在石莼目藻类中观察有丝分裂的有效抑制剂。
