Z rings form precisely at midcell in the <i>noc minCD</i> double mutant.

<p>Spores of the double-mutant (SU681) and wild-type (SU5) strain were germinated in PAB at 34°C. Cells were fixed in ethanol or prepared for immunofluorescence to visualize FtsZ. (A) Mean length of the wild-type and double-mutant outgrown cells collected at 90, 120, 150 and 180 min after spore germination and prepared for ethanol-fixation. Error bars are µm ± SEM. (B and C) Z ring position plotted in relation to the predicted position of potential division sites (dotted lines; 1/2, 1/4, 1/8, 3/8) in the wild-type (B) and double mutant (C) strains at 150 min of spore outgrowth. Bottom-left corner shows the mean cell length of the cells plotted (µm ± SEM). (D and E) Z ring position at the first (medial) division site in the wild-type (D) and the double-mutant (E) cells at 120 min and 150 min of spore outgrowth, respectively. Top left-hand corner shows the average cell length of the cells plotted (µm ± SEM). (F and G) FtsZ localization in wild-type (F) and double-mutant (G) at 120 min of spore outgrowth. Cell containing a midcell Z ring in the double-mutant strains is outlined. (H and I) FtsZ localization in the double-mutant at 150 min (H) and at 180 min (I) of spore outgrowth. (Ii) Amplification of the white rectangle in (I) showing helical-like patterns of FtsZ. Carets point to accumulations of FtsZ at division sites and triangles point to Z rings in the double mutant. Images are phase contrast (left), and FtsZ immunofluorescence (right). Scale bars are 2 µm.