Unit structures of macromolecular layer in the cell wall of Bacillus aneurinolyticus

In order to clarify the morphological details of the unit structures in the macromolecular layer (MML) of the bacterial cell wall, ghost cells of Bacillus aneurinolyticus were observed with the electron microscope in the negatively stained specimens. The unit structures usually showed a ring image with the central dot of PTA-deposit or an image of paired rodlets sandwiching a stripe of PTA-deposit between them even in the same wall. The author concluded from these images that an unit structure must be a cylindrical body with a central canal. Then, a new name "unit cylinder" was given to it. Rough measurements of the unit cylinder were also performed. Rigidity and elasticity of the cell wall were considered as based upon the morphological features and the array pattern of the unit cylinders. Therefore, the MML was regarded as a skeleton structure of the cell body. Besides, the MML consisting of the unit cylinders with central canals was considered to be an ultra-micro-filter from the viewpoint of metabolism in bacterial physiology.