Ultrastructural study on mitosis and cytokinesis in Scytosiphon lomentaria zygotes (Scytosiphonales, Phaeophyceae) by freeze-substitution
Ultrastructural study on mitosis and cytokinesis in Scytosiphon lomentaria zygotes (Scytosiphonales, Phaeophyceae) by freeze-substitution
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DOI：
10.1007/s007090200015
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发表时间：
2002-01-01
期刊：
影响因子：
2.9
通讯作者：
Motomura, T
中科院分区：
文献类型：
--
作者：
Nagasato, C;Motomura, T
用冷冻固定和置换法研究了花管藻受精卵有丝分裂和胞质分裂的超微结构。在有丝分裂过程中，核膜大部分保持完整。中心体的纺锤体微管（MT）穿过核膜的间隙进入核质。在分裂后期和末期，两个子染色体团部分被内质网包围。末期后，核膜重建，形成两个子核。然后，几个大的空泡占据了子核之间的空间。来自中心体的MT向两个子核之间的中平面延伸，在液泡中。当时，中心体附近的高尔基体活跃地产生许多囊泡。在子核中间，聚集了小球状囊泡和管状池。这些来自高尔基体的小泡从中心体运输到未来的分裂平面。然后，胞质分裂通过这些小泡的融合而进行，但不通过质膜的开槽。在完成与质膜的连续性之后，细胞壁材料沉积在质膜之间。在新生隔的周围仍可见管状池。用这种方法不能观察到微丝。我们的结论是，在褐藻的胞质分裂收益的高尔基体囊泡和管状池的融合，而不是由一个开沟的质膜。
The ultrastructure of mitosis and cytokinesis in Scytosiphon lomentaria (Lyngbye) Link zygotes was studied by freeze fixation and substitution. During mitosis, the nuclear envelope remained mostly intact. Spindle microtubules (MTs) from the centrosome passed through the gaps of the nuclear envelope and entered the nucleoplasm. In anaphase and telophase, two daughter chromosome masses were partially surrounded with endoplasmic reticulum. After telophase, the nuclear envelope was reconstructed and two daughter nuclei formed. Then, several large vacuoles occupied the space between the daughter nuclei. MTs from the centrosomes extended toward the mid-plane between two daughter nuclei, among the vacuoles. At that time, Golgi bodies near the centrosome actively produced many vesicles. Midway between the daughter nuclei, small globular vesicles and tubular cisternae accumulated. These vesicles derived from Golgi bodies were transported from the centrosome to the future division plane. Cytokinesis then proceeded by fusion of these vesicles, but not by a furrowing of the plasma membrane. After completion of the continuity with the plasma membrane, cell wall material was deposited between the plasma membranes. The tubular cisternae were still observed at the periphery of the newly formed septum. Microfilaments could not be observed by this procedure. We conclude that cytokinesis in the brown algae proceeds by fusion of Golgi vesicles and tubular cisternae, not by a furrowing of the plasma membrane.