Which component of the Gendre solution is used to hydrolyze nuclei?

• A. Alcohol, 95% saturated with picric acid.
• B. Formaldehyde, 37-40%.
• C. Glacial acetic Acid.
• D. 10% ammonium (sodium or potassium) hydroxide in 70% alcohol.

Answer: (A)

Hydrolyzing the nuclei in this method is accomplished by the mildly acidic alcoholic medium provided by the picric acid–saturated alcohol. The 95% alcohol, saturated with picric acid, creates the right acidic environment and solvent balance to hydrolyze nucleic acids without overly damaging tissue structure. This step exposes reactive sites needed for subsequent staining. The other components don’t perform this hydrolysis: fixatives like formaldehyde cross-link; glacial acetic acid and alkaline alcohol would alter staining in different ways and aren’t the hydrolysis agent in this procedure.