Peter-Jürgen Müller

Kinetics and Regulation of Erythrogenic Toxins Type A and C During Growth of Streptococcus Pyogenes

The production of erythrogenic toxins type A (ETA) and C (ETC) is described as a function of growth kinetics. Group A streptococcal strains C 203 S and NY 5 were cultivated in yeast-peptone extract, Todd-Hewitt medium and a synthetic medium. Two main growth phases occurred during growth: a first logarithmic phase and a second linear phase. These phases were separated by a short stationary interphase caused by limitation of the amino acids L-serine and L-leucine. Maximum production of ETC was observed during the logarithmic phase, it was correlated to a high level of viable cells. ETA was produced mainly during the short stationary interphase. The production of ETC is regulated by L-isoleucine. A stagnation or reduction of the concentration of viable cells was observed during the interphase. The phosphate limitation caused during streptococcal growth induced expression of the extracellular protein phosphatase and surprisingly, of a serine proteinase activity. The association between these results and the pathogenicity of streptococci is discussed.

Kinetics of growth and product formation in cultures from streptococci of groups a and c

During growth of streptococci of Lancefield groups A and C in a culture medium containing glucose, yeast extract and peptone, two main growth phases occur: growth phase I and growth phase II (diauxic growth). They are separated by a short stationary phase (1st stationary phase). The diauxic growth is caused by transient limitations as well as the availability of new sources of the amino acids L-serine and L-arginine. Growth phase I consists of an exponential and a nearly linear part. These growth kinetics are reflected by the kinetics of gas metabolism as well as by product formation. Hyaluronic acid is formed during the nearly linear phase whereas the enzyme alkaline phosphatase, is exclusively excreted in the 1st stationary phase. Also carbon dioxide and L-lactate are mainly produced in a growth phase-dependent mode. In the late stationary phase (2nd stationary phase) more oxygen is consumed whereas the demand for oxygen in the 1st stationary phase is nearly zero.

Influence of the Phosphorylation State on the Biological Activity of a Low-molecular Mitogen from Group A Streptococci

A low molecular weight mitogen (LMP) from Streptococcus pyogenes strain NY 5 was successively purified by adsorption on phenylsepharose, chromatography on Resource S and Superdex G 30 and finally by affinity chromatography on antiphosphothreonine agarose. The N-terminal protein sequence of the mitogen was determined. The occurrence of phosphoamino acids was investigated by immunoassay using monoclonal antibodies. The LMP is a threonine-phosphorylated protein different of HPR protein of PTS-system, its mitogenic activity was lost after treatment with streptococcal protein phosphatase or alkaline phosphatase. The inactivated LMP was activated by phosphorylation with phosphokinase and ATP. The active LMP was also inactivated in streptococcal cultures secreting acid protein phosphatase during the phase of phosphate limitation.

Metabolism of phosphate-limited cultures of Streptomyces IV. Protein-phosphorylation of antibiotics-producing cultures

It has been demonstrated that in the cellular proteins of Streptomyces hygroscopicus JA 6599 and Streptomyces noursei JA 3890 b, the producers of the antibiotics turimycin and nourseothricin, respectively, phosphorylated proteins are present. Numbers and concentrations of phosphorylated proteins decreased during the idiophase as characterized by phosphate limitation, antibiotic biosynthesis and phosphatase formation. Phosphoamino acids of serine, threonine and tyrosine were found in the hydrolysates of proteins. Protein tyrosyl kinase was demonstrated in the cellular extracts. The results supports the hypothesis that protein phosphorylation possesses a function in the regulation of growth and secondary product formation.