Basic dyes for the staining of DNA in mammalian tissues and absorption spectra of stained nuclei in the visible light.

This communication presents informations on the staining of DNA with basic dyes, such as ethyl violet, Janus green, a new red dye obtained from Janus green, and Giemsa, belonging to different chemical groups. It has been found that DNA of tissue sections from which RNA has been extracted selectively with cold concentrated phosphoric acid can be stained with aqueous solutions of these dyes. Further, DNA of tissue sections from which RNA has been extracted and the sections then hydrolysed in 6 N HCl at 28 degrees C for 15 min can also be stained with aqueous solutions of ethyl violet, Janus green, and Giemsa. Moreover, tissue sections that have been hydrolysed in 6 N HCl and then stained with aqueous solutions of these dyes, including the new red dye obtained from Janus green, reveal well-stained nuclei. The absorption spectra of nuclei stained with aqueous solutions of ethyl violet, Janus green and Giemsa, following the above stated three procedures of staining have been presented. Absorption data of nuclei stained with the new red dye after Feulgen hydrolysis of tissue sections as well as those of nuclei in tissue sections from which RNA has been extracted have also been presented herein. The implications of these findings have been discussed.