Bennett W N
Department of Biological Sciences, University of Wisconsin-Milwaukee 53201.
Arch Environ Contam Toxicol. 1990 Jan-Feb;19(1):118-23. doi: 10.1007/BF01059819.
Cadmium (Cd) toxicity and amelioration of Cd toxicity by Mn were measured in Chlorella pyrenoidosa, using turbidostat culture. The responses were measured in terms of the maximum specific growth rate, mu max, of the populations. In turbidostat culture mu max is a dependent variable that can be measured continuously. Cd (as CdCl2.2.5 H2O) was added to control populations at a concentration of 1.8 microM Cd. Toxicity was expressed after a 5 generation lag and resulted in a mu max steady state 62% lower than the initial control after 2 generations. With continued Cd exposure, Mn (as MnCl2.6H2O) was then added stepwise to a concentration of 10.4 microM Mn which caused a rapid, immediate increase in mu max followed by linear increase until a steady-state plateau was reached at a mu max 90% of control. The ameliorative response spanned 20 culture generations. After addition of Mn (10.4 microM), cellular Cd concentration did not change and cellular Mn concentration increased. Increase in mean cell size accompanied Cd exposure and was significantly decreased when supplemented with 10.4 microM Mn. Possible mechanisms of the amelioration are discussed.
利用恒浊器培养，测定了莱茵衣藻中镉（Cd）的毒性以及锰对镉毒性的改善作用。通过群体的最大比生长速率（μmax）来衡量这些反应。在恒浊器培养中，μmax是一个可以连续测量的因变量。向对照群体中添加浓度为1.8微摩尔/升镉（以CdCl₂·2.5H₂O形式）。在5代的延迟期后表现出毒性，两代后导致μmax稳态比初始对照低62%。在持续镉暴露的情况下，然后逐步添加锰（以MnCl₂·6H₂O形式）至浓度为10.4微摩尔/升锰，这导致μmax迅速立即增加，随后呈线性增加，直到在μmax达到对照的90%时达到稳态平台。改善反应跨越20个培养代。添加锰（10.4微摩尔/升）后，细胞镉浓度没有变化，细胞锰浓度增加。平均细胞大小的增加伴随着镉暴露，当补充10.4微摩尔/升锰时显著降低。讨论了可能的改善机制。
