Characteristic Properties and Biological Significance of Stable Protoplast Type L-Forms

Compared to other organisms surrounded by cell walls bacteria show a great variability of their cell envelopes. Numerous terms and definitions have been used to characterize the different cell wall deficient bacterial forma (protoplasts, gymnoplasts, quasiprotoplasts, mureinoplasts, sphero-plasts, soniplasts, L-forms, L-variants, L-phase organisms). They can be reduced to 4 main types: protoplasts, spheroplasts, protoplast type L-forms, and spheroplast type L-forms (Fig. 1).