Color enhanced TEM of ultra-thin sections of Corynebacterium diptheriae. Unusual shape of bacterium contains large amounts of glycogen granules. A membrane bound structure dominates the lower interior of the cell. Mesosome (an infolding of the plasma membrane as well as a septum, involved in division) growing inward from the cell wall are seen. Corynebacteria are rod-shaped, gram-positive and nonmotile. Though many of the species are pathogens in domestic animals, birds and plants, the most important is the species C. diptheriae--the causative agent of diptheria in humans. The disease is characterized by the formation of a false membrane on any mucous surface and occasionally on the skin. In nasal diptheria, fever is a much more evident symptom. Adenitis is often severe, with serious discharge from the nostrils, which may be blood tinged. Myocarditids and late neuritis are commonly present. TEM Magnification = x26,500 at 70mm