Sit K H, Bay B H, Wong K P
Department of Anatomy, Faculty of Medicine, National University of Singapore, Kent Ridge.
Anat Rec. 1993 Feb;235(2):183-90. doi: 10.1002/ar.1092350202.
The rounding up of mitotic human Chang liver cells in monolayer culture was studied quantitatively. It was surprising to find significant reduction in cell surface area considering that endocytosis has been demonstrated to be at a complete standstill in M phase. Uptake studies using impermeant BCECF (2',7'-bis(2-carboxyethyl)-4(5)-carboxyfluorescein free acid) pH indicator and particulate neutral red dye in aqueous buffer showed preferential internalization into mitotic cells in direct contrast to expectation since interphase cells do not have arrested endocytosis. However, infolded plasma membrane ruffles and internalized extracellular material were demonstrated in prophase cells, much like those seen in interphase rounding via the induction of intracellular alkalinizations. Raised intracellular pH (pHi) is a universal and consistent finding in M phase cells. Despite cessation of small pit endocytosis, it remains possible for plasma membrane internalization to be a causal factor in the observed surface area reduction in mitotic rounding.
对单层培养的有丝分裂期人类 Chang 肝细胞的变圆过程进行了定量研究。令人惊讶的是，尽管已证明内吞作用在 M 期完全停止，但细胞表面积却显著减小。在水性缓冲液中使用非渗透性 BCECF（2',7'-双（2-羧乙基）-4（5）-羧基荧光素游离酸）pH 指示剂和颗粒状中性红染料进行的摄取研究表明，与预期相反，有丝分裂细胞优先摄取，因为间期细胞的内吞作用并未停止。然而，在前期细胞中观察到了内陷的质膜褶皱和内化的细胞外物质，这与通过诱导细胞内碱化在间期变圆过程中看到的情况非常相似。细胞内 pH（pHi）升高是 M 期细胞普遍且一致的现象。尽管小窝内吞作用停止，但质膜内化仍有可能是有丝分裂变圆过程中观察到的表面积减小的一个因果因素。
