Hennessey T L, Rubin H
Cancer Res. 1986 Dec;46(12 Pt 1):6041-8.
An in vitro line of transformed BALB/3T3 mouse fibroblasts was exposed to a 100 mM increase in the NaCl concentration of its growth medium. The rate of growth, as measured by the incorporation of tritiated thymidine, decreased almost 100-fold during the first 24 h of exposure to the hyperosmotic medium and then increased approximately 10-fold during the second 24 h of exposure. Cell counts of cultures passaged in medium with excess NaCl revealed a gradual increase in growth rate over a period of several weeks. The early kinetics by which salt tolerance developed in this cell line indicated a process of physiological adaptation rather than selection of preexisting variants in the control population. Clonally derived populations exposed to excess NaCl all showed a similar response. Cultures which tolerated a 100 mM increase in NaCl also grew well in medium containing 200 mM sucrose, indicating that their tolerance was not specific for NaCl. Although the initial response of cultures exposed to excess NaCl appeared to be one of physiological adaptation, tolerance for salt became hereditary after continued passage in hyperosmotic medium. Cultures that were returned to control conditions after prolonged exposure to excess NaCl inherited a high level of tolerance for salt which persisted for several hundred generations without selection.
将一株转化的BALB/3T3小鼠成纤维细胞体外培养系置于其生长培养基中NaCl浓度增加100 mM的环境下。通过掺入氚标记的胸腺嘧啶核苷来测定生长速率，在暴露于高渗培养基的最初24小时内，生长速率下降了近100倍，然后在接下来的24小时暴露期间增加了约10倍。在含有过量NaCl的培养基中传代培养的细胞计数显示，在几周的时间里生长速率逐渐增加。该细胞系中耐盐性形成的早期动力学表明这是一个生理适应过程，而非从对照群体中选择预先存在的变体。克隆衍生的群体暴露于过量NaCl时均表现出相似的反应。耐受NaCl浓度增加100 mM的培养物在含有200 mM蔗糖的培养基中也生长良好，这表明它们的耐受性并非NaCl特有的。尽管暴露于过量NaCl的培养物的初始反应似乎是生理适应之一，但在高渗培养基中持续传代后，对盐的耐受性变得可遗传。长时间暴露于过量NaCl后再回到对照条件的培养物继承了高水平的耐盐性，且在没有选择的情况下持续了几百代。
