FINE STRUCTURE OF THE REITER TREPONEME AS REVEALED BY ELECTRON MICROSCOPY USING THIN SECTIONING AND NEGATIVE STAINING TECHNIQUES

Abstract

Applying both thin sectioning and negtaive staining techniques, the fine structure of the Reiter treponeme has been revealed by electron microscopy.The cell envelope, which is shown as a three-layered membrane in sections, encloses inclusively both the cell body and the axial filament twisting around the cell. In addition to the cell envelope, the cytoplasm is surrounded by the cell membrane composed of three layers: outer and inner dense layers and an intermediate lighter layer. The cell membrane resembles the cytoplasmic membrane of bacteria in appearance and size, but it seems to have the nature of both the cell wall and the cytoplasmic membrane. The nuclear fibrils run parallel to the longitudinal axis of the cell in the central region of the cytoplasm. The membranous organelles, presenting membranous stacks, laminated bodies and tubular structures, are situated in the cytoplasm, and they seem to correspond to the intracytoplasmic membrane system of bacterial cells. Dense granules in the cytoplasm are probably the polyphosphate granules since they are volatilized by electron bombardment.
Whole cells and isolated axial filaments of the treponeme were negatively stained with phosphotungstate. Immediately after sonic oscillation, the cell envelope is ruptured and consequently the axial filament consisting of a bundle of about 6 fibrils becomes free. Each fibril of the axial filament penetrates separately into the cytoplasm near the end of the cell. The fibril is composed56 KAWATA AND INOUE Vol. 8, No. 2of the core and the sheath. As the digestion of the cells with trypsin proceeds, large membranous bodies, corresponding to the membranous organelles in sections, becomes distinctly visible in the partially digested cytoplasm.