[Spontaneous L-transformation in actinomycetes].

Spontaneous L-transformation was described in Actinomadura and Nocardiopsis. Cultures growing for two days were found to contain polymorphous cells (0.5 to 1.5 mum) lacking a cell wall. A considerable portion of the cell is occupied with a nucleoid while the cytoplasm is forced toward the periphery of the cell. Membranous structures formed by five-layer membranes can be seen in the cytoplasm. Budding has been observed. The above features are typical of bacterial L-forms and has not been found in cells with an intact cell wall.