Summary: The growth on solid medium of organisms of the pleuropneumonia group as seen in electron micrographs was compared with the growth in liquid media described in a previous paper (Klieneberger-Nobel & Cuckow, 1955). There is no evidence of a rigid cell wall in these organisms, a finding consistent with those electron micrographs of growth in liquid media and in light microscopical preparations. The newly formed minimal reproductive units, hitherto never demonstrated in the light microscope except when they have grown to a larger size, are here demonstrated in large numbers as a uniform phase of small, delicate elements, the diameter of which measures c. 100 mμ. in the electron micrographs.
KlienebergerE.,
SmilesJ.1942; Some observations on the developmental cycle of the organisms of bovine pleuropneumonia and related organisms. J. Hyg., Camb 42:110
SmithW. E.,
HillierJ.,
MuddS.1948; Electron micrograph studies of two strains of pleuropneumonia-like (L) organisms of human derivation. J. Bact 56:589
TurnerA. W.1935; A study of the morphology and life cycles of the organism of pleuropneumonia contagiosa bovum (Borrelomyces peripneumoniae nov.gen.) by observation in the living state under darkground illumination. J. Path. Bact 41:1