Structural Studies of the Surface Projections of Chlamydia Trachomatis By Electron Microscopy

Rod-like projections on the surface of Chlamydia trachomatis have been studied by a combination of computer image analysis and electron microscopy. the rods, c. 60-80 Å in diameter and c. 500 Å in length, were found on the surface of prokaryocells of C. trachomatis inserted in the cytoplasmic membrane through a ring-like structure in the outer membrane. the rod-like structures were found at all stages of the life cycle, even in very small elementary bodies (EBs) of C. trachomatis and in vesicles < 0.2 μm. Computer image analysis of isolated rods indicated that they comprise helically arranged subunits with a periodicity of c. 50 Å. From their localisation and distribution, these structures may be related to the proliferation, or to the infectivity, of chlamydiae.