Science. 1957 Nov 8;126(3280):961-4. doi: 10.1126/science.126.3280.961.
The molecular nutritional requirements exhibited by mammalian cells can vary with the following conditions: whether the cells are plated singly or in massive inoculum; whether a clonal strain or a mixture of different genotypes is employed; whether the macromolecular fraction of serum used as a supplement was previously exposed to prolonged dialysis or other procedures which may release bound micromolecules. In addition, the nature of the medium in which the cells were previously grown, the time permitted for incubation of the cells in the test medium, and the presence of substances or conditions which may specifically introduce the need for certain molecules to preserve balance can strongly influence nutritional requirements. This great versatility may reflect the ability of the mammalian cell to assume different metabolic states characteristic of specific types of differentiation. Under certain conditions, growth of single HeLa cells of the S3 clonal strain requires the presence of cholesterol at a level of 0.5 to 1 microgram per milliliter.
细胞是单独培养还是大规模接种；使用的血清大分子部分是否先前经过长时间透析或其他可能释放结合的小分子的程序处理；细胞先前在其中生长的培养基的性质、细胞在测试培养基中孵育的时间、以及可能专门引入对某些分子的需求以保持平衡的物质或条件。这种巨大的多功能性可能反映了哺乳动物细胞能够呈现出特定分化类型的不同代谢状态的能力。在某些条件下，S3 克隆株的单个 HeLa 细胞的生长需要胆固醇的存在，其水平为每毫升 0.5 至 1 微克。
