Osmotic Stability andSodiumandPotassium Content ofL-Forms ofStreptococcus (aecalis

A stable L-form ofStreptococcus faecalis (T53) was transferred inmedia containing decreasing concentrations ofsucroseuntil itgrew inmediumwithout addedosmotic stabilizer. ThisL-form (designated T53,) was compared withT53 fromwhichitwas derived. Thesurvival ofthese twoL-forms suspended atdifferent osmolalities showed thatmaximal survival forT58I was 350to400milliosmolalandforT,3 was 900to1,000 milliosmolal. Bothpeaks were attheosmolality oftheir growth media. Measurement ofintracellular potassium andsodiumshowedthattheconcentration ofthese ions was reduced inT,3,1. Manybacterial L-forms areosmotically fragile, requiring electrolytes, sucrose, orother osmotic stabilizers inthemediumtosurvive. Although L-forms ofa numberofspecies of gram-negative bacilli havebeengrownwithout osmotic stabilizer, streptococcal L-forms have usually required sucrose orNaClinthemedium(3). Inthepresent study, wehaveexamined a stable L-form ofStreptococcus faecalis trained togrowinmediawithout osmotic stabilizer. Theability ofthisL-form tosurvive atdifferent osmolalities andintracellular levels of NaandK ionshasbeencompared withtheLformfromwhichitwasderived growing in mediacontaining 0.5Msucrose.