AN ALTERNATIVE METHOD FOR PREPARATION OF SCHIFF-LIKE REAGENT FROM OSMIUM AMMINE COMPLEX FOR SELECTIVE STAINING OF DNA ON THIN LOWICRYL SECTIONS

Batches of osmium-ammine (OA) complex vary considerably in staining pr operties when used in a Feulgen-like reaction for selective staining o f DNA-containing structures. An alternative procedure for preparation of Schiff-like reagent from OA complex is described. It is based on ge neration of H2SO3, respectively SO2, within the OA solution and ensure s more favorable conditions for production of a Schiff like stain than bubbling with SO2 does. The method is reproducible and yields high st aining intensity. Data obtained suggest that the ability of OA complex to produce Feulgen-like staining is strongly influenced by variations in its chemical composition. Their unfavorable effect can be overcome by selecting suitable conditions for preparation of a Schiff-like rea gent. Conditions for obtaining specific and sensitive Feulgen-like sta ining are determined.