抄録
A quantitative analysis of cell organelles was carried out by electron microscopy on synchronized populations of mouse leukemia L 5178 Y cells. The ratio of total mitochondrial volume-to-cytoplasmic volume (volume density of mitochondria) increased gradually from G1 to G2 through mid-S phase. The number of mitochondria per cell was nearly constant from G1 to mid-S phase but increased significantly from mid-S to G2 phase. The volume density of lysosomes increased by about 40% from mid-S to G2 phase, while no remarkable difference was detected in the volume density between G1 and mid-S phase. The surface area of rough-surfaced endoplasmic reticulum in unit volume of cytoplasm (surface density of rER) increased by about 140% from G1 to G2 phase. The volume density of Golgi apparatus increased by a small amount during interphase. The volume density of lipid bodies was the highest at mid-S phase, whereas their number per unit volume of the cytoplasm (numerical density of lipid bodies) decreased continuously from G1 to G2 phase through mid-S phase. The significance of these results is discussed with reference to mitochondria) proliferation, lysosomal activity and membrane turnover.
