Coordinated Incorporation of Nascent Peptidoglycan and Teichoic Acid into Pneumococcal Cell Walls and Conservation of Peptidoglycan During Growth

Choline-containing pneumococcal cell wals are sensitive to autolysin, whereas ethanolamine-containing walls are not. Bacteria were labeled with radioactive peptidoglycan precursors while growing either in choline- or in ethanolaminecontaining media. Subsequently, the labeled cells were allowed to grow for four to five generations in nonradioactive medium supplemented with the alternative amino alcohol source (i.e. cells labeled in choline medium yields ethanolamine; cells labeled in ethanolamine medium yields choline). The autolysin sensitivity of the isotope label in cell walls prepared from such bacteria indicates that nascent peptidoglycan and teichoic acid units that are synthesized at the same time are attached to one another, incorporated into the cell surface at the cellular equator, and remain conserved during growth the division of the bacteria.