[Electron microscopic studies of fine structure on the oral spirochetes]

Of the strains isolated from periodontitis patients in this laboratory, seven pure cultures with different characteristics were subjected to a scanning electron microscope and transmission electron microscope (negative staining, thin section and freeze-etching method were employed) for the cell morphology investigations. The following results were obtained; 1) Cells were thin, long and twisted to make thme spirals. Some differences were observed in cell length and width, even though in a same isolated strain. 2) It was obvious that the basic cell structure of oral spirochetes consisted of the following seven parts; i.e., outer envelope, axial fibrils, main body, cytoplasm, nucleous structure, ribosomes and fine fibrils. 3) The specific structures, which should be called tubulous and/or ring-like structures, were shown in certain strains. They obviously located at the cell surface of oral spirochetes. 4) Outer envelope, which locates at the most outside layer of the cell, composed with two membranous structures holding one fine granular structures in it, and fold completely the main body and axial fibrils. 5) It was noted that the one end of axial fibrils locating at the space between outer envelope and main body fused with main body resulting in formation of a specific disk-like structure. 6) The surface of the main body was double-layered membranous structures. 7) Nucleous structure, ribosomes, and fine fibrils which were slender than axial fibrils were in the cytoplasm.