Effect of magnesium and iron on the growth of and production of extracellular proteins by Staphylococcus aureus strain S-6
1988
Hirooka, E.Y. | De Salzberg, S.P.C. | Bergdoll, M.S.
The effect of magnesium and iron on the growth, cellular morphology, deoxyribonuclease, coagulase, and enterotoxin B (SEB) production of Staphylococcus aureus strain S-6 in a pancreatic digest of casein (NAK) which had been treated with aluminum to remove mineral ions was determined. Growth of S. aureus in the treated NAK medium (NAKSA) was minimal; The morphology of the cells was heterogenous with many large cells as well as some that were gram negative. The cells gradually reverted towards normal as the Mg2+ concentration was increased to 1.1 microgram/ml. Cell dry weight increased from 0.36 +/- 0.27 mg/ml to 1.16 +/- 0.41 mg/ml, DNase activity increased from 7.6 units/mg dry weight to 77.0 units/mg dry weight, and SEB production increased from 12.2 to 54.3 microgram/mg cell dry weight when the Mg2+ content was increased to 1.1 microgram/ml. Increasing the Fe2+ content above the 0.4 microgram/ml in the NAKSA medium containing 1.1 microgram/Mg2+ resulted in decreases in dry weight and DNase activity, a slight increase in SEB production, and a relatively large increase in coagulase production.
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