Ultrastructure and capsule of Mycoplasma meleagridis

The ultrastructural study of Mycoplasma meleagridis utilized the electron microscope techniques of sectioning, histochemical staining, critical-point drying, and freeze etching. The predominant morphotype was a spherical form ranging in diameter from 200 to 700 nm. The other morphotypes were dumbbell-shaped cells interconnected by membranous tubules, and chains of streptococcal-like cells. These forms suggest replication by binary fission. An extracellular structure in the form of a capsular matrix was observed by staining with ruthenium red and potassium tellurite, and was also seen in specimens prepared by critical-point drying and freeze etching.