Question

You measured the diameter of the micronucleus using fluorescence microscopy and electron microscopy. How do the measurements compare?

Answer 1

Electron microscopes differ from light microscopes in that they produce an image of a specimen by using a beam of electrons rather than a beam of light. Electrons have much a shorter wavelength than visible light, and this allows electron microscopes to produce higher-resolution images than standard light microscopes.

For light microscopy, the nucleus is usually stained with orcein, Giemsa, or DAPI. These “nuclear stains” do not actually stain the nucleus but rather the chromatin or DNA contents within it. Consequently, when the nuclear shape is different from the chromatin shape such as within the mitotic nucleus and many stages of conjugation, staining can give a misleading interpretation of nuclear size, position, and behavior.

By electron microscopy the nuclear envelope may be clearly visible, but the shape and position of the dynamic, sometimes elongate, Micronuclei can be difficult to observe, however each component of the micronucleus can be distintly viewed and this is where the two methods can be compared.