STREPTOCOCCAL L FORMS II

Abstract

The chemical composition of a group A beta hemolytic Streptococcus and its corresponding osmotically fragile L form is compared. Osmotically protective washing procedures must be employed for chemical analyses of the L form to be meaningful. Washing this form with distilled water results in complete cellular disintegration and loss of as much as 40% of the total nucleic acid content. No difference in the total nucleic acid content of the coccus (12.37%) and its intact L form (12.11%) is found when a protective washing procedure (0.3 M sucrose) is employed. Cold trichloroacetic acid extracts of these organisms contain a greater amount of UV absorbing material when cultured at a low (0.1%) rather than a high (1.5%) glucose concentration. Complete amino acid analyses and carbohydrate investigations of the coccus and its protected L form revealed that ornithine and the major cell wall carbohydrates (glucosamine, rhamnose, and muramic acid) are absent in the L form. The same predominating amino acids as well as a high content of serine and leucine are found in the L form as compared with the parent streptococcus. These differences cannot be accounted for in the L form by dry weight differences due to loss of the streptococcal cell wall.