Anisimov A P
Tsitologiia. 1997;39(2-3):218-28.
Mechanisms of polyploidization of albumen gland cells of S. lauta have been studied using squash preparations in combination with autoradiography of DNA synthesis. During the growth period of the gland normal and abnormal (polyploidizing) mitoses were noticed in addition to endomitoses. Diploid foot cells and poorly differentiated secretory cells are reproduced by the normal mitosis (2c : 2c). These poorly differentiated secretory cells go then through polyploidization by different means. Tetraploid nuclei are substantially formed by abnormal mitoses (4c), which take 40-60% of all mitoses. Metaphase blocks (C-mitosis type) dominate among them; anaphase blocks and their sequences (bladed nuclei) occur rarely. The abnormal polyploid series 3c-6c ... and hypoploid (2c, 3c) mitoses originate from asymmetric mitoses (1c : 3c). Singular nuclei are defined as endomitotic even in the first cycles (4c, 6c). The second and following cycles of the main polyploid nuclei series ... 8c-16c-32c and of alternative series ... 12c-24c pass through endomitosis of classical (insect) type (Geitler, 1939). Unlabelled endomitoses were observed in an hour, while labeled ones were seen in 8-24 hours after 3H-thymidine injection. So, endomitosis can be defined as a real phase of the cell cycle. Integrity of the nuclear envelope as the formal feature of endomitosis was proven at the ultrastructural level (Anisimov, 199). It is emphasized that the normal mitosis is followed by an abnormal polyploidizing mitosis and then by endomitosis. These processes could be considered as compatible and successive polyploidization mechanisms. This conclusion is in agreement with dynamics and speed of DNA and RNA synthesis during cell polyploidization and differentiation (Anisimov, 1988, 1994b, 1995b).
利用压片标本结合DNA合成的放射自显影技术，对光滑双脐螺蛋白腺细胞多倍体化的机制进行了研究。在腺体生长期间，除了核内有丝分裂外，还观察到正常和异常（多倍体化）有丝分裂。二倍体足细胞和分化程度低的分泌细胞通过正常有丝分裂（2c:2c）进行增殖。这些分化程度低的分泌细胞随后通过不同方式进行多倍体化。四倍体核主要由异常有丝分裂（4c）形成，占所有有丝分裂的40%-60%。其中中期阻断（C-有丝分裂类型）占主导；后期阻断及其序列（叶片状核）很少出现。异常多倍体系列3c-6c……和亚倍体（2c、3c）有丝分裂起源于不对称有丝分裂（1c:3c）。即使在第一个周期（4c、6c），单个核也被定义为核内有丝分裂。主要多倍体核系列……8c-16c-32c和替代系列……12c-24c的第二个及后续周期通过经典（昆虫）类型的核内有丝分裂（盖特勒，1939年）。注射3H-胸腺嘧啶核苷1小时后观察到未标记的核内有丝分裂，而在8-24小时后观察到标记的核内有丝分裂。因此，核内有丝分裂可被定义为细胞周期的一个真实阶段。在超微结构水平上证实了核膜的完整性是核内有丝分裂的形式特征（阿尼西莫夫，199）。需要强调的是，正常有丝分裂之后是异常多倍体化有丝分裂，然后是核内有丝分裂。这些过程可被视为兼容且连续的多倍体化机制。这一结论与细胞多倍体化和分化过程中DNA和RNA合成的动态变化及速度一致（阿尼西莫夫，1988年、1994b、1995b）。
