[Development of protoplasts of Streptomycetes on media favoring the regeneration and formation of L-forms].

The protoplasts of three Streptomyces species and their regenerative ability were studied using light microscopy. When Streptomyces lividans and S. erythraeus protoplasts are cultivated on regeneration media, their regeneration is not synchronous during the first day; some protoplasts revert to yield the mycelial form and also L-forms of these cultures are produced. If the protoplasts are transferred to a medium inducing L-forms, they grow and multiply for a long time with the production of L-form colonies. This process is maintained if S. lividans L-form cells are passaged on the medium inducing L-forms, but the protoplasts revert to yield the mycelial form on the regeneration medium.