Miniature cell formation in Chlamydia psittaci.

In an electron microscope study on the developmental cycle of the goat pneumonitis strain of Chlamydia psittaci in L cells, it was observed that miniature reticulate bodies, measuring approximately 0.2 mum in diameter and surrounded by double unit membranes, were produced infrequently from normal-sized reticulate bodies through a "budding"-like process. As little as 0.1 mug of penicillin per ml greatly increased the frequency of the miniature reticulate body formation.