Function of cell wall teichoic acid in thermally injured Staphylococcus aureus

Abstract

Thermally injured cells of S. aureus lack the ability to grow on tryptic soy agar containing 7.5% NaCl. This injury phenomenon was examined in 3 strains of S. aureus: MF-31; H (Str); and, isolated from H (Str), 52A5, a mutant which lacks teichoic acid in the cell wall. Temperatures for sublethal heat treatment were selected to produce maximum injury with minimum death for each strain. Examination of isolated cell walls showed that Mg was lost from the wall during heating, and that the degree of cell injury was accentuated when Mg2+ were removed from or made unavailable to the cell. S. aureus 52A5 was more heat sensitive than its parent strain. Cells containing higher levels of wall teichoic acid generally showed less injury than normal cells. Cells with the weaker cation-binding polymer, teichuronic acid, in the cell wall generally showed greater injury. Cell wall teichoic acid of S. aureus apparently aids in the survival of the cell by the maintenance of an accessible surface pool of Mg.