Mitotic spindle formation in Triparma laevis NIES-2565 (Parmales, Heterokontophyta).
Mitotic spindle formation in Triparma laevis NIES-2565 (Parmales, Heterokontophyta).
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Triparma laevis NIES-2565（Parmales，Heterokontophyta）有丝分裂纺锤体的形成。
DOI：
10.1007/s00709-016-0967-x
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发表时间：
2016
期刊：
影响因子：
2.9
通讯作者：
S.
中科院分区：
文献类型：
--
作者：
Yamada;K.;Nagasato;C.;Motmomura;T.;Ichinomiya;M.;Kuwata;A.;Kamiya;M.;Ohki;K. & Yoshikawa;S.
并列藻类拥有硅质壁，代表着硅藻的姐妹谱系；它们被认为是理解硅藻进化的关键类群。硅藻具有良好的特征和独特的有丝分裂结构，但Parmales的有丝分裂机制尚不清楚。本文用透射电子显微镜观察了石斑鱼间期和有丝分裂过程中的微管排列。间期细胞有四个或五个中心粒(∼长80 nm)，从中心粒向细胞质发出。在早期，MTS束出现在核外部位。中心粒相对于MT束的位置在其伸长过程中发生了变化。在较短的MT束的外侧(∼590 nm)和延长的MT束的两侧(∼700 nm)均可观察到中心粒。中期，纺锤体由两种类型的MTS-MT束和单个MTS(可能是动粒MTS)组成，前者穿过核中央的细胞质隧道，后者可能从极点延伸到核。核膜仅在动粒MTS穿透的区域消失。末期，子代染色体向两极迁移，分离染色体之间出现MT束。这些观察表明，MT在细胞周期中并不总是发生在中心粒的外围，纺锤体也经常发生。莱维斯的形态与硅藻相似。
The parmalean algae possess a siliceous wall and represent the sister lineage of diatoms; they are thought to be a key group for understanding the evolution of diatoms. Diatoms possess well-characterized and unique mitotic structures, but the mitotic apparatus of Parmales is still unknown. We observed the microtubule (MT) array during interphase and mitosis inTriparma laevisusing TEM. The interphase cells had four or five centrioles (∼80 nm in length), from which MTs emanated toward the cytoplasm. In prophase, the bundle of MTs arose at an extranuclear site. The position of centrioles with respect to an MT bundle changed during its elongation. Centrioles were observed on the lateral side of a shorter MT bundle (∼590 nm) and on either side of an extended MT bundle (∼700 nm). In metaphase, the spindle consisted of two types of MTs-MT bundle that passed through a cytoplasmic tunnel in the center of the nucleus and single MTs (possibly kinetochore MTs) that extended from the poles into the nucleus. The nuclear envelope disappeared only at the regions where the kinetochore MTs penetrated. In telophase, daughter chromosomes migrated toward opposite poles, and the MT bundle was observed between segregating chromosomes. These observations showed that MT nucleation does not always occur at the periphery of centrioles through cell cycle and that the spindle ofT. laevishas a similar configuration to that of diatoms.