ELECTRON MICROSCOPE STUDIES OF THE INTRACYTOPLASMIC MEMBRANE SYSTEM IN CLOSTRIDIUM TETANI AND CLOSTRIDIUM BOTULINUM

Abstract

The vegetative cells and sporulating cells of Clostridium tetani and Clostridium bolulinum were examined electron-microscopically by the use of ultrathin sectioning, negative staining, and carbon replica techniques, focusing especially on the observa-tion of the intracytoplasmic membrane system (ICMS). The ICMS which originated from the inward development of the cytoplasmic membrane, could be recognized in the cytoplasm of the vegetative cells of both organisms. The configuration of the ICMS was diverse, exhibiting a multilayered, tubular, vesicular, or reticular ap-pearance. The ICMS was clearly observable in negatively stained whole cell pre-parations, presenting an entire and somewhat stereographical view.
The participation of the ICMS in new septum formation of dividing cells was also recognized. Furthermore, in sporulating cells, it was observed that the forespore membrane was produced by the infolding and the extension of the cytoplasmic membrane into the cytoplasm. The initial spore coat appeared at first fragmentarily in the sporangial cytoplasm surrounding the outer unit membrane layer of the forespore membrane without any appreciable relation with the forespore membrane or the cytoplasmic membrane, and then gradually proceeded to envelope the whole spore portion.
In both negatively stained and carbon replica preparations one to several crescent-or sickle-shaped wrinkles or protrusions on the surface of the cell ends were visible. They were considered to correspond to the marked inner structural changes accom-panying the sporulation and cell division processes.
By observing the carbon replica and chromium-shadowed preparations of cell wall fraction of both organisms, a regularly arranged striped surface pattern with about 125 A or 140 A striation intervals was visible.