In situ hybridization. (A) Hematoxylin and eosin staining. P textilis venom gland showing acini (a) lined with single layer of epithelium. (B) NBT/BCIP (nitro-blue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate p-toluidine salt) staining. Localization of nonenzymatic subunit of pseutarin C mRNA in P textilis venom gland by in situ hybridization using DIG-labeled purified PCR product as probe. Arrows indicate gene-specific staining. The mRNA of pseutarin C is localized to the columnar epithelial cells. Original magnification, × 10.