A TECHNIQUE FOR STAINING CHROMOSOMES OF THE MOUSE WITH SUDAN BLACK B.

Abstract

Sudan Black B (National Analine Division NZB-1, NZB-7) used in combination with formic, propionic, and lactic acids, has been found to be ideal as a stain fixer for chromosomes of the mouse. The stock solutions are 1% SBB in 100% propionic acid, 1% SBB in 85% lactic acid, and 1% SBB in 20% formic acid. The final reagent consists of one part each of the above and one part distilled water. The mixture is filtered through paper and stored at room temperature. The squash method is used and stain is added directly to material on the slide or may be stained in a small receptacle and then placed on the slide. Sufficient stain to cover the material completely should be used and maximum staining is achieved in 10 to 60 minutes. Sudan Black B does not overstain. Care should be taken upon application of the cover slip to avoid slippage. After cover slipping, slides are dehydrated according to Bridges (1937), Stain Technol. 12:51-52. Slides are mounted permanently with Euparol or Diaphane (Will Corp.) and blotted with absorbent paper. Slides prepared according to this technique show no evidence of deterioration or fading after 8 years of use and storage.