Growth of bacterial L forms and bacterial protoplasts.

Numerous morphological, physiological, and biochemical studies have been carried out on bacterial forms exhibiting a pronounced osmotic fragility (for review see Weibull, 1958b). Naked bacterial protoplasts, obtained by means of a complete removal of the cell wall by lysozyme in a sucrose medium (Weibull, 1953) offer an example of such an osmotically fragile structure. Osmotically sensitive forms may also result when the cell wall is only partly degraded. Such structures have been named spheroplasts (Hurwitz et al., 1958; Michael and Braun, 1959). The so-called bacterial L forms, which are highly pleomorphic and which may arise when normal bacteria are subjected to an unfavorable environment, are also markedly sensitive to changes in the osmotic pressure of the surrounding medium (for reviews see Dienes and Weinberger, 1951; Klieneberger-Nobel, 1951; Tulasne, 1953; Schellenberg, 1954). The present paper describes some investigations concerning the growth of a stable L form, of bacterial protoplasts, and of the normal bacteria from which these forms were derived. Liquid media were used for the experiments. Samples of the bacterial material were taken at various times during growth and were analyzed chemically. The data obtained show that the growth characteristics of the bacterial forms studied agree in many respects. Differences, however, also exist.