Protein staining of ribboned epon sections for light microscopy

Summary Procedures are described for obtaining and handling ribboned epon sections 0.3–2 thick for light microscopy, and for the cytological application of two intense acid dyes, Aniline Blue Black and Coomassie Brilliant Blue R 250. The technique allows precise localization of proteins and some other materials, and, because the sections are ribboned, facilitates three-dimensional visualization of the structures involved. The dyes may be used in combination with the periodic acid-Schiff reaction and with autoradiography.This work was supported in part by a Public Health Service fellowship 5-F2-GM-22, 031-02 to the author and in part by NSF grant GB 3460 to Dr. W. A. Jensen.