Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences (ICG SB RAS), Novosibirsk, 630090, Russia.
Department of Anatomy, Division of Histology and Cell Biology, School of Medicine, Jichi Medical University, Shimotsuke, Japan.
Protoplasma. 2022 Sep;259(5):1371-1376. doi: 10.1007/s00709-021-01725-y. Epub 2021 Nov 23.
In this study, intercellular nuclear migration (INM), also known as cytomixis, was documented in cryofixed plant meiocytes for the first time. Intact tobacco inflorescences and flower buds as well as dissected individual anthers were cryofixed in liquid nitrogen by plunge freezing. Cryosubstituted and cryosectioned male meiocytes were analyzed by light microscopy. For cryosubstitution, the frozen material was kept in acetic alcohol at - 70 °C for 1 week. For cryosectioning, the frozen material was sectioned at - 20 °C, and fixed with precooled acetic alcohol. Fixation of the intact tobacco inflorescences in Carnoy's solution was used as a control. Microscopy revealed good preservation of cell structure in the cryofixed anthers, flower buds, and inflorescences. INM was detectable in all the studied cryofixed and chemically fixed samples. The cytological picture of INM observed in the cryofixed meiocytes did not noticeably differ from the picture obtained with the chemically fixed cells. These results indicate that INM is observable irrespective of whether a physical or chemical fixation method is employed, with minimal damage from handling. Our results contradict the notion that INM is a phenomenon caused by mechanical, osmotic, or chemical artifacts during sample preparation.
在这项研究中，细胞间核迁移（INM），也称为细胞融合，首次在冷冻固定的植物减数分裂细胞中被记录下来。完整的烟草花序和花蕾以及分离的单个花药通过浸入液氮中进行冷冻固定。通过光显微镜分析冷冻替代和冷冻切片的雄性减数分裂细胞。对于冷冻替代，将冷冻材料在-70°C的乙酸酒精中保持 1 周。对于冷冻切片，将冷冻材料在-20°C下切片，并使用预冷的乙酸酒精固定。使用 Carnoy 溶液固定完整的烟草花序作为对照。显微镜显示冷冻固定的花药、花蕾和花序中的细胞结构保存良好。在所有研究的冷冻固定和化学固定样品中都可以检测到 INM。在冷冻固定的减数分裂细胞中观察到的 INM 的细胞学图像与用化学固定细胞获得的图像没有明显区别。这些结果表明，无论使用物理还是化学固定方法，只要处理造成的损伤最小，INM 都是可以观察到的。我们的结果与 INM 是在样品制备过程中由于机械、渗透或化学人为因素引起的现象的观点相矛盾。
