Initiation of wall assembly sites in Streptococcus faecium.

In electron micrographs of replicas of Streptococcus faecium, sites of wall growth are located between pairs of raised equatorial bands. Analysis of cells taken from cultures with mass doubling times between 30 and 125 min indicates that rounds of wall synthesis are initiated at a time close to division, which is temporally unrelated to the initiation or termination of chromosome replication. Growth sites are initiated at a relatively constant volume independent of growth rate when the volume contained within the two segments of wall adjoining an equatorial band marker approaches ca. 0.26 micrometer 3.