High concentration of calcium ions in Golgi apparatus

The interphase NIH3T3 cells were vitally fluorescentstained with calcium indicator fluo-3 and Glogi probe C6NBD-ceramide, and then the single cells were examined by laser scanning confocal microscopy (LSCFM) for subcellular distributions of Ca2+ and the location of Golgi apparatus. In these cells, the intracellular Ca2+ were found to be highly concentrated in the Golgi apparatus. The changes of distribution of cytosolic high Ca2+ region and the Golgi apparatus coincided with the cell cycle phase.In calcium free medium, when the plasma membrane of the cells which had been loaded with fluo-3/AM were permeated by digitonin, the fluorescence of the Golgi region decreased far less than that of the cytosol. Our results indicated that the Glogi lumen retained significantly high concentration of free calcium.

dbcAMP对小鼠U_(14)腹水型瘤细胞的影响——扫描电镜观察和流式细胞光度计分析

本文根据扫描电镜观察,报告了dbcAMP引起小鼠U_(14)腹水瘤细胞微绒毛和质膜表面的细微形态变化。U_(14)腹水瘤的多数细胞体积大,大小相近,表面有许多细长微绒毛;微绒毛表面和微绒毛间细胞质膜表面,仅见很细微的点状微突。腹腔内注射dbcAMP的U_(14)腹水瘤,85%以上的细胞体积缩小,大小不等,表面微绒毛缩短且减少。在没有微绒毛的部位,细胞质膜表面有许多颗粒状微突起,较对照组明显易见。微绒毛表面也有与之大小类似的微突起,使微绒毛表面凹凸不平。流式细胞光度计分析结果表明,在本文实验条件下,dbcAMP未引起U_(14)腹水瘤细胞周期的变化,细胞膜表面和微绒毛的变化,也不单纯是细胞周期中微绒毛数量和分布的改变。因此作者认为,这些变化不是通过改变细胞周期引起的。cAMP引起微绒毛退缩的机制不详。至于微绒毛间的颗粒状微突起是微绒毛退缩的遗迹,抑或是由cAMP引起,尚待研究。cAMP引起瘤细胞表面形态的变化,进一步证明了cAMP在小鼠体内诱导恶性细胞分化的作用。