Cell wall assembly in Bacillus subtilis: location of wall material incorporated during pulsed release of phosphate limitation, its accessibility to bacteriophages and concanavalin A, and its susceptibility to turnover.

Addition of a pulse of phosphate to a phosphate-limited chemostat culture of Bacillus subtilis W23 led to the synthesis of teichoic acid and the consequent development by the bacteria of the ability to bind phage SP50. In cultures growing at different rates, phage-binding properties became maximal approximately one generation time after addition of the pulse. Removal of the incorporated teichoic acid by turnover also reached its maximum rate after a similar interval. After pulsed release of phosphate limitation in B. subtilis NCTC 3610, the alpha-glucosyl residues of the incorporated teichoic acid, detected by their interaction with concanavalin A, became maximally exposed at the same time that phage binding was maximum. At that time the bacteria bound phage all over the cylindrical part of the surface and at about one-third of the polar caps. That fraction of the receptor material that is exposed soon after its incorporation was distributed along the cylindrical length of most of the bacteria, but few phages bound to the polar caps, except in the case of short bacteria; these bound phages in a markedly asymmetric manner at one pole and along their length. The significance of these results is discussed in relation to the mode of assembly of the cell wall.