FIGURE 1.

Pneumococcal cell division morphology. Following the initial formation of the Z-ring and divisome machinery, septal and peripheral PG synthetic complexes begin to make new PG as invagination begins (A). Two concentric rings of newly synthesised PG surrounding the existing sacculus form as a result, whilst a portion of MapZ, FtsZ, EzrA, and FtsA (MapZ Ring) begin to migrate to the new equators. For simplicity, newly synthesised peripheral PG is drawn as a single orange colour, but likely consists of some mixture of newly synthesised peripheral PG attached to remodelled septal PG (see Trouve et al., 2021) (B). Septal PG synthesis continues to close the central septum whilst peripheral PG synthesis continues to elongate the cell from midcell (C). This process continues until the septum is closed. The divisome machinery then migrates to the midcells of the newly formed daughter cells and the cycle repeats (D). Note that pneumococcus exists natively as encapsulated cells that are often in chains of divided cells (Barendt et al., 2009).