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SUMMARY : Certain strains of Streptococcus pyogenes produced a starch-like sub- stance in the presence of maltose and plasma. Amylolytic strains of group A streptococci produced larger amounts of the substance than other strains of these organisms. The substance was elaborated in the presence of optimal concentrations of plasma, with either starch, glycogen or maltose in the medium. It was not pro- duced when either glucose-1 -phosphate, glucose, cellobiose, melibiose, saccharose or lactose was substituted for maltose. The amylolytic properties of certain strains of group A streptococci were reported by Keogh & Simmonds (1940) and by Crowley (1950,1954). The latter found that amylase production was a property of certain variants, and that amylase-positive organisms not infrequently lost the property during sub- culture on medium containing plasma. The effect of serum and plasmaon amylase production was further studied, and this paper reports findings related to (1) the effect of plasma on the liberation of amylase, and (2) the formation of a starch-like substance. METHODS Strains. The history of six group A strains used is shown in Table 1. All of the strains were originally received from the Streptococcal Reference Labora- tory, Public Health Laboratory Service. Table 1. The group A streptococci used in the experiments

The Formation of a Starch-like Polysaccharide from Maltose by Strains of Streptococcus pyogenes