Osmotic stability and sodium and potassium content of L-forms of Streptococcus faecalis.

A stable L-form of Streptococcus faecalis (T(53)) was transferred in media containing decreasing concentrations of sucrose until it grew in medium without added osmotic stabilizer. This L-form (designated T(53I)) was compared with T(53) from which it was derived. The survival of these two L-forms suspended at different osmolalities showed that maximal survival for T(53I) was 350 to 400 milliosmolal and for T(53) was 900 to 1,000 milliosmolal. Both peaks were at the osmolality of their growth media. Measurement of intracellular potassium and sodium showed that the concentration of these ions was reduced in T(53I).