[The M-protein heterogeneity of Streptococcus pyogenes strains isolated from clinically healthy and ill children in an organized collective].

The study of the kinetic curves of the lysis of group A S. pyogenes cell-walls (cells), serovars 29 and 12 M, variants M+ and M-; with endo-N-acetyl-muramidase revealed that the kinetics of the lysis of virulent and avirulent strains was different: variant M- was lyzed faster than M+. This difference in the cell-wall lysis of both variants made it possible to use this method for the identification of M+ and M- states of the strains.

[The heterogeneity of Streptococcus pyogenes strains isolated from clinically healthy and sick children in an organized collective].

Experiments on typed strains used as an example revealed that kinetic curves obtained in the lysis by endo-N-aretylmuramidase of virulent strains greatly differed from those obtained from nonvirulent ones: the lysis rate of M+ variants was less than that of M- variants; M- strains gave rather steep kinetic curves of lysis, while those of M+ strains were more declivous. In this study group A S. pyogenes cultures isolated from healthy and sick children in a summer camp were used.

[The biochemical and immunological properties of group A type M 29 streptococci cultured in the presence of a bovine blood serum preparation].

The influence of the preparation of cattle blood serum on group A streptococcus, type M 29, has been studied. The study has revealed that the addition of 17% of dialysis water obtained from a fraction of cattle blood serum to the standard culture medium (3% Todd-Hewitt broth) produces changes in the amino acid composition of the cell walls of M+ variant without altering the antiphagocytic resistance of the mutant thus obtained. The dialysate of the pepsin digest of the cell walls of the mutant contains Fc-receptors and receptors to fibrinogen, while the initial strain contains only receptors to fibrinogen which are, in this case, the pepsin fragments of M protein.