Ultrastructural alteration of the cell surface of Staphylococcus aureus cultured in a different salt condition

Staphylococcus aureus growing in a normal NaGI medium has a specific NaGI tolerance property to grow in the medium contain. ing NaGl in as high a concentration as over 10%. In our comparative study of the cells proliferating in the normal NaGI medium and 10% NaGl medium, we have observed the following differences aside from the changes of lipid composition in the cytoplasmic membrane previously reported. 1. S. aureus grown in high NaGl medium undergoes changes as to increase its size and reduce its surface area. 2. The thickness and weight of cell wall are increased to about 1. 7 times and 1. 32 times, respectively. 3. The protoplast prepared from S. aureus growing in the high NaGI medium shows a weaker resistance to hypotonic condition than that from normal cell.