Edelmann L
Fachbereich Theoretische Medizin, Universität des Saarlandes, Homburg/Saar, FRG.
Scanning Microsc Suppl. 1991;5(4):S75-82; discussion S82-4.
A new adsorption staining method for transmission electron microscopy is described by means of which cellular adsorption sites of alkali-metal ions can be visualized in freeze-substituted and low temperature embedded biological material. The main features of this staining method are: 1) the use of Cs(+)-ions which are known to accumulate in living cells like K(+)-ions and 2) the removal of the staining solution from thin sections of the embedded material by centrifugal force. It is shown that sections of freeze-substituted and Lowicryl embedded frog skeletal muscle which has not been treated with chemical fixatives can be stained with electron-dense Cs(+)-ions: protein sites of preferential ion adsorption are visualized. These sites are similar to those accumulating monovalent ions in living cells as had been shown previously with frozen-hydrated preparations. An observed pH-dependency of the adsorption staining is consistent with the view that the ion adsorption sites are beta- and gamma-carboxyl groups of cellular proteins. The results obtained so far indicate that the new method can be used to investigate weak interactions between cellular proteins and different ions by electron microscopic methods.
本文描述了一种用于透射电子显微镜的新型吸附染色方法，通过该方法可以在冷冻替代和低温包埋的生物材料中观察到碱金属离子的细胞吸附位点。这种染色方法的主要特点是：1）使用已知会像钾离子一样在活细胞中积累的铯离子；2）通过离心力从包埋材料的薄片中去除染色溶液。结果表明，未经化学固定剂处理的冷冻替代和Lowicryl包埋的青蛙骨骼肌切片可以用电子致密的铯离子染色：优先离子吸附的蛋白质位点得以显现。这些位点与先前在冷冻水合制剂中显示的活细胞中积累单价离子的位点相似。观察到的吸附染色的pH依赖性与离子吸附位点是细胞蛋白质的β-和γ-羧基这一观点一致。目前获得的结果表明，该新方法可用于通过电子显微镜方法研究细胞蛋白质与不同离子之间的弱相互作用。
