Effect of Teichoic Acid on Resistance to the Membrane-lytic Agent of Streptococcus zymogenes

Abstract

The resistance of S. zymogenes to its own lytic agent has been shown to be due to the production of a specific, inhibitory teichoic acid. A survey of streptococcal strains showed that only strains resistant to the lytic agent produced the specific inhibitor. In addition, the inhibitor can be removed from spheroplasts of resistant strains, thereby making them sensitive to the lysin. Throughout the early part of the growth cycle, the inhibitor is associated with the cell and cannot be found in the medium. During late logarithmic phase, however, the inhibitor is released into the medium by the cells, and therefore is a contributing factor to the apparent lability of the lytic agent. The purified, inhibitory teichoic acid contains ribitol, phosphate, glucose, and D-alanine. The alkaline lability of the biological activity of the teichoic acid was correlated with the hydrolysis of the D-alanine. A streptococcal strain which is sensitive to the membrane-lytic agent produced an inactive ribitol teichoic acid which lacks the ester-linked D- alanine, whereas a lysin-resistant mutant of this strain produces a teichoic acid which contains D-alanine and which has inhibitory activity.