The Accumulation of Extracellular Macromolecules by Staphylococcus aureus Grown in the Presence of Sodium Chloride and Glucose

Abstract

SUMMARY When grown in broth cultures containing sodium chloride and glucose, Staphylococcus aureus JHM produced protein, RNA and DNA in the culture fluid. Maximum yields were obtained with about 4 % (w/v) sodium chloride and 0·1 % (w/v) glucose. Accumulation of macromolecules began at the end of exponential growth and was accompanied by a decrease in culture turbidity. Electron microscopy revealed considerable cellular lysis, arising from rupture of newly formed septa. Before lysis occurred, the cocci exhibited many morphological abnormalities. After incubation for about 15 hr the culture showed evidence of fresh growth and the resulting cocci were characterized by abormally thick and uneven walls. The results suggest that there was interference with the regulation of cell-wall synthesis, perhaps due to loss of mesosomes, which were never seen in the cytoplasm of organisms grown in sodium chloride glucose broth.