Abstract
The ultrathin cryo-section has several advantages in the detection of enzyme activities at the light and electron microscopic levels, as it permits quick freeze fixation, and affords better penetration of the reaction medium. To establish a reliable technique for enzyme histochemistry, good visualization of ultrastructure and good retention of enzyme activities are necessary. The authors applied a covered negative staining with silicotungstate to visualize fine morphology on the ultrathin cryo-sections which demonstrated enzyme activity, after treatment with yellow ammonium sulfide. This technique makes it possible to demonstrate different enzyme activities on the same organelle by means of serial sections.
In decalcified bone tissues, alkaline phosphatase activity is detectable on ultrathin cryo-sections but not on 40μm sections without the magnesium reactivation procedure required for the usual enzyme histochemistry.
