An improved procedure is reported for the histochemical localization of glucose-6-phosphate dehydrogenase in fresh-frozen sections of animal and plant tissues. Used in this procedure are an incubation medium and an inert high-molecular-weight polyvinyl alcohol as a stabilizer to check enzyme diffusion. The incubation medium consists of 10 mg each of nicotinamide adenine dinucleotide phosphate and nitroblue tetrazolium chloride and 60 mg of glucose-6-phosphate per 20 ml of 22% polyvinyl alcohol solution in 0.2 M Tris-maleate buffer, pH 7.2. Use of this medium has given consistent results with the tissues tested. Because the use of an electron-transfer agent in the incubation medium often resulted in enzyme diffusion, its use in glucose-6-phosphate dehydrogenase localization is considered undersirable. Incubation time of 15 to 30 min for animal tissue and 20 to 45 min for plant tissue of 37degreesC was found to be optimal for producing the characteristic blue formazan at the reaction sites.
Triterpenic glycosides have been reported to have spermicidal potential, furthermore "CONSAP" cream, with these constituents as the active compounds, has reached clinical trial as a male contraceptive (1). Panax and other araliacious plants are rich sources of triterpenic glycosides. We recorded 100% immobilization of human spermatozoa by the ethanolic extract of the fresh leaves of Pentapanax leschenaultii (DC). Seem at the 2% level when assayed by the methods reported (2, 3). Since the plant has not been investigated, chemical analyses of the light petroleum-and n-butanol-soluble portions of the extract were carried out. The corn
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