Studies on the chromosome by scanning electron microscope--a new trial with long-term Giemsa staining.

Chromosomes, which can be seen under a light microscope (LM) as bands, are too thin to see with a scanning electron microscope (SEM). We noticed that chromosomes increase in thickness with Giemsa staining, so that scanning microscopic specimens could be prepared by long-time Giemsa staining for SEM observation, and in the present study the following results were obtained. 1) When the duration of the trypsin treatment was kept constant, and the Giemsa staining was performed from 30-min to 24-h, it was found that the thickness of the chromosomes increased with the length of treatment time, and the fibrous structures were clearly seen. 2) While a sufficient thickness of the chromosomes was obtained with the long-time Giemsa staining, the bands became unclear as the time of staining was extended. 3) A long-time Giemsa staining without trypsin treatment showed more "highly packed" fibers, so that the trypsin treatment was felt to be related to the dispersion of the fibers.