Septation in Zymomonas mobilis

Abstract

Freeze-etching and thin sectioning have been used to demonstrate that the gram-negative rod, Zymomonas mobilis ATCC 29191, divides by septation. During this division process the plasma membrane and peptidoglycan grow symmetrically inwards into the cytoplasm at the cell centre, leaving the outer membrane behind at the cell surface. The outer membrane continues to grow causing it to bleb vesicles into the external milieu. Once the septum aperture has closed, the nascent peptidoglycan of the septum splits in two; next, the outer membrane travels inwards between the two new peptidoglycan layers separating the cells. Once this inward growth is finished, cell separation is complete.