On the mode of in vivo assembly of the cell wall of Bacillus subtilis.

During logarithmic growth Bacillus subfilis synthesizes teichoic acid, but not teichuronic acid. Under conditions of phosphate limitation, teichoic acid synthesis stops, and teichuronic acid synthesis is activated. Suitable radioactive labeling experiments have shown that both of these polymers are attached only to glycopeptide chains synthesized at the same time as these specialized polymers are made. An examination of the teichoic acid glycopeptide complex obtained by lysozyme digestion from cells labeled with D[aH]glucosamine during a period of phosphate limitation, and with D-[14C]glucosamine after resumption of logarithmic growth, has shown that the glycan chains adjacent to those linked covalently to teichoic acid represent a nearly random selection of new and old chains. This last finding is interpreted to indicate that during cell wall growth there is a random intercalation of new and old glycopeptide chains.