Hayflick life span (Hayflick界限)
1961年,Leonard Hayflick利用来自胚胎和成体的成纤维细胞进行体外培养,发现:胚胎的成纤维细胞分裂传代50次后开始衰退和死亡,相反,来自成年组织的成纤维细胞只能培养15~30代就开始死亡。Hayflick等还发现,动物体细胞在体外可传代的次数,与物种的寿命有关;细胞的分裂能力与个体的年龄有关,由于上述规律是Hayflick研究和发现的,故称为Hayflick界限。
Goods are carried by several of transport--on road or rail, by sea or air.
people are no longer worried about whether their food is safe or not they enjoy a better life.
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