[L-forms of streptococcus in the scanning electron microscope. 1. Structural elements of L-colonies]

Broth culture of stable L-forms of beta-hemolytic streptococcus, group A, was studied in the log phase. Internal portion of the centrifugate constituting the matrix of the L-population represented a structureless mass in which the borders of individual cells were not always distinct; the cells adhered to one another and were irregular in shape. The described morphological picture corresponded to the internal part of the L-colonies from the semifluid medium in observation under phase and scanning microscope. A more peripheral portion of the centrifugate was formed by the spherical cells, about 2 mum in diameter; penetrating holes or crater-like invaginates and also small spherical structures, about 0.5 mum in diameter were often revealed on these cells. Filamentous structures, up to 200 mum in length which protruded far into the surrounding environment served as the most peripheral elements. Analogous structure were described in the L-colonies examined by phase contrast microscopy. The data of transmission and scanning microscopy are compared.