[Electron microscope study of the plasmid DNA from various strains of Treponema pallidum]

Electron microscopic investigation and electrophoretic analysis of DNA from two cultural strains of pale treponemes (Treponema pallidum VIII and Treponema pallidum Reiter) allowed us to identify the circular molecules of plasmid DNA their size evaluated as 7 to 8 MD. Side by side with the molecules of this size the electron microscopic pictures of the plasmid DNA of both strains of pale treponemes show small superspiralized molecules of plasmid DNA. According to electrophoretic data the size of this DNA is evaluated as two thousand base pairs.