Direct observation of iron-induced conformational changes of mitochondrial DNA by high-resolution field-emission in-lens scanning electron microscopy

摘要

When respiring rat liver mitochondria are incubated in the presence of Fe(III) gluconate, their DNA (mtDNA) relaxes from the supercoiled to the open circular form dependent on the iron dose. Anaerobiosis or antioxi- dants fail to completely inhibit the unwinding. High- resolution field-emission in-lens scanning electron micros- copy imaging, in concert with backscattered electron detec- tion, pinpoints nanometer-range iron colloids bound to mtDNA isolated from iron-exposed mitochondria.