Bénard J, Riou G, Saucier J M
Nucleic Acids Res. 1979;6(5):1941-52. doi: 10.1093/nar/6.5.1941.
The kinetoplast DNA networks of Trypanosoma cruzi exist under two forms which have been studied by equilibrium density centrifugation in CsCl gradients containing ethidium bromide and by band sedimentation analysis. The relative proportion of the two forms has been measured and varies significantly between the exponential and stationary phase of growth, suggesting that one of these forms is a replicative intermediate. Both forms exhibit very high sedimentation coefficients. The sedimentation velocity ethidium titration was used to measure the superhelix density of the kinetoplast DNA after having established the validity of the method with in vitro closed DNA networks. The superhelix density of the native form of the kinetoplast DNA minicircles is very low and varies according to the physiological state of the trypanosomes. Furthermore, we observed a significant increase of the superhelix density of the kinetoplast DNA of trypanosomes grown in the presence of ethidium.
克氏锥虫的动基体DNA网络以两种形式存在，这两种形式已通过在含有溴化乙锭的CsCl梯度中进行平衡密度离心以及条带沉降分析进行了研究。已测量了这两种形式的相对比例，并且在生长的指数期和稳定期之间有显著差异，这表明其中一种形式是复制中间体。两种形式都表现出非常高的沉降系数。在用体外封闭DNA网络确定该方法的有效性之后，使用沉降速度溴化乙锭滴定法来测量动基体DNA的超螺旋密度。动基体DNA小环天然形式的超螺旋密度非常低，并且根据锥虫的生理状态而变化。此外，我们观察到在溴化乙锭存在下生长的锥虫的动基体DNA的超螺旋密度显著增加。
