Preparation of a new red dye from Janus black and its use in the staining of DNA-aldehyde molecules.
This communication presents a method for the preparation of a new red dye from an aqueous solution of Janus black by adding NHC1 and sodium thiosulphate to it. This new red dye when used on acid-hydrolysed tissue sections reveals the presence of red nuclei when sections after staining are dried between folds of filter paper, differentiated in n-butanol, cleared in xylene and mounted. Similarly stained sections when treated with SO2 water show partial leaching of the dye from the nuclei. Tissue sections when treated with cold concentrated phosphoric acid for 20 min and then stained with an aqueous solution of Janus black reveal the presence of orange-red nuclei. The new red dye obtained from Janus black does not respond to treatment under UV rays. The in vitro absorption data of the red dye indicate peaks at 210, 270 and 545 nm. The in situ absorption spectra of nuclei stained with the new red dye following Feulgen procedure reveal the peak of maximum absorption at 560 nm and those of nuclei treated with cold concentrated phosphoric acid and then stained with this red dye reveal peak at 530--540 nm. Some relevant points raised out of this investigation have been discussed.