[Transmission electron microscopic studies of fine structure by fast freeze method on Actinomyces israelii ATCC...

Recently, one of the major objectives was to observe cellular structures in biological-materials including microorganisms as raw as possible. For this purpose, Actinomyces israelii ATCC 12102, an experimented strain, was fixed by a fast freeze method using liquid nitrogen as a cryogen, followed by transmission electron microscopic observations on fine structures. Then, the following results were obtained. 1) Cell wall was an electron dense and thick monolayer. In certain cells, numerous granules were found on cell walls, showing lamellar structures. The cell wall surface to be a wave like structure of which limit was unclear. 2) Cytoplasmic membrane consisted of two electron less dense layers holding an electron dense layer in then. However, fine layers with different electron density crossed over one another, representing a formation of stripe structure in other cells. 3) In cytoplasm, we observed that fine fibers with high electron density crossed over fine fibers with low electron density. 4) We also observed that the specialized ring structure in cytoplasm.