Ziervogel H, von Zglinicki T
Humboldt-Universitt zu Berlin, Sektion Biologie.
Acta Histochem Suppl. 1990;39:477-8.
It is quite common that the different procedures for isolation of nuclei make use of the purifying effect of sedimentation through concentrated sucrose. For this reason we investigated by light and electron microscopy the changes of chromatin structure in dependence on the amount and sort of ions present in the solution used for isolation and resuspension of nuclei. A decreasing concentration of monovalent cations (Na+, K+) leads to a swelling of the whole nuclei in consequence of the decondensation of the chromatin fibres. This change of nuclear structure can be reversed by small additions (0.5-1.5 mM) of divalent cations (Mg2+, Ca2+, Cu2+). Inasmuch as each change of the electrostatic balance within the nucleoplasm causes morphological alterations also the pH of the solution influences the chromatin structure. Data of X-ray-microanalysis have established the importance of divalent cations for the maintenance of a certain nuclear structure under conditions of low ionic strength.
通过浓缩蔗糖沉降的纯化作用来分离细胞核的不同程序相当常见。因此，我们通过光学显微镜和电子显微镜研究了染色质结构的变化，该变化取决于用于分离和重悬细胞核的溶液中存在的离子数量和种类。单价阳离子（Na +、K +）浓度的降低会导致染色质纤维解聚，进而使整个细胞核肿胀。通过少量添加（0.5 - 1.5 mM）二价阳离子（Mg2 +、Ca2 +、Cu2 +），这种核结构的变化可以逆转。由于核质内静电平衡的每一次变化都会导致形态改变，所以溶液的pH值也会影响染色质结构。X射线微分析数据证实了在低离子强度条件下二价阳离子对于维持特定核结构的重要性。
