Evidence for Taxonomic Utility of Periodic Acid-Thiocarbohydrazide-Silver Proteinate Cytochemical Staining for Electron Microscopy

Abstract

Various species of bacteria belonging to taxonomically separate genera were studied by using EM and different cytochemical staining methods. Judging from these results and those reported previously in the literature, it is concluded that the periodic acid-thiocarbohydrazide-silver proteinate reaction (Thiery method) separates the bacteria into 4 large groups according to the production of silver grains at the site of the cell wall or the cytoplasmic membrane or both. In the Corynebacterium-Mycobacterium-Nocardia group only the cytoplasmic membrane reacts; in Bacillus and Brucella only the cell wall reacts; in Lactobacillus and Microbacterium the cell wall and the cytoplasmic membrane react; and in Escherichia and Clostridium neither the cell wall nor the cytoplasmic membrane reacts. This staining method clearly separated M. leprae from certain leprosy-derived coryneform bacteria.