[Speroplast behavior in cultures of Thermus ruber]

Spheroplasts spontaneously originating in cultures of Thermus ruber, which are cultivated on potato-peptone media, are capable of growth and multiplication. They may reach 10 mc in diameter. Spheroplasts multiply by budding which can be preceded with inner division or budding; as a result 2--9 and more protoplast bodies are formed under the "envelope" of a spheroplast. Self-reproduction of spheroplasts is most active in a semiliquid potato-meat-peptone medium containing 0.2--0.3 per cent of agar. Microcolonies, which are clusters of spheroplasts in the process of budding, are formed at 45 degrees C in this medium during 1--2 days. Reversion of spheroplasts to rod-like cells occurs if L-lysine and/or DL-alpha-aline are added to the potato-peptone medium. Spheroplasts spontaneously produced by Thermus ruber are similar to the unstable type of L-form in their fine organization and behaviour in cultures.