A SIMPLIFIED SILVER DIAMMINE METHOD FOR THE STAINING OF NUCLEIC-ACIDSIN POLYACRYLAMIDE GELS

High sensitivity and low background, which are the significant feature s of the procedure of Johansson and Skoog (J. Biochem. Biophys. Method s. 1987, 14, (Suppl.) 33) for silver staining of nucleic acids in poly acrylamide gels, have been improved by excluding ethanol From all solu tions and increasing the length of washing steps after sensitisation a nd staining. Including a fixation step before sensitisation increased the contrast of the bands even at high concentration of nucleic acid, producing a shift in the tone of colour from black to grey instead of gold to yellow bands. This technique is superior in terms of sensitivi ty and background to a number of other silver staining protocols, thre e which utilise silver diammine and three which utilise silver nitrate ions.