盘基网柄菌AK127细胞超微结构的观察

The Ultrastructural Observation on Dictyostelium discoideum AK127 Cells

盘基网柄菌AK127细胞是gP150蛋白基因被剔除的突变细胞。为探明发育期间AK127细胞亚显微结构特征,用透射电镜观察了发育14h、16h、20h的细胞,结果表明:发育14h细胞内含丰富内质网系统,由内质网组织围裹细胞质密度明显低于周围的细胞质,能清楚地观察到多层膜组成的多膜结构。细胞核的内核膜产生凹陷,使内外核膜间产生一个含丝状物质的泡状空间,内核膜上可见螺旋状染色物质,外核膜表面布满颗粒状物质。发育到16 h时,多膜结构内某些膜开始解体,形成自噬泡。线粒体膜性结构完整。发育20 h细胞内有一个内含数个多膜结构的大自噬泡。据此笔者推测多膜结构作为一个储备营养成分"仓库",为维持细胞生命所用。这些数据提示gp150分子的缺失对于细胞的结构和生理过程均有较大影响,gp150分子在细胞生长和发育过程中起重要作用。

Dictyostelium discoideum AK127 cells are the lagC protein gene knock-out mutant strains. We studied the AK127 cells ultrastructural characteristic in the development of 14 h, 16 h and 20 h of cells with a transmission electron microscopy. The result showed that the 14 h of cells contained rich endoplasmic reticulum system. The density of cytoplasm wrapped around by the endoplasmic reticulum significantly lower than the surrounding cytoplasm. Abundant multi-membrane structure can be observed clearly. Because of inner nuclear membrane depression, some bubbly spaces containing filamentous material are produced between out nuclear membrane and inner nuclear membrane. Some spiral chromatins are suspended on inner nuclear membrane and out nuclear membrane is covered by granular materials. Development to 16 h, some membranes in the multi-membrane structure commence to disrupt and several autophagic vacuoles begin to emerge. In the developement 20h cells, a large autophagic vacuole containing several multi-membrane structures can be observed. According to this, we presumes that these multi-membrane structures may be regarded as a reserve nutrients ＂warehouse＂, in order to maintain cell life. These results suggest that absence of gp150 have a certain relationship with bubbly nuclei, multi-membrane structure and disappearing of endoautophagy in mitochondrion. We consider that gp150 is a key factor in Dictyostelium discoideum cell differentiation and development.