Fig. 9.

GFP-L-MltG localize differently from FtsZ-L-RFP. (A) Representative phase and fluorescent images of strain IU10353 (ftsZ-L₂-mKate2 gfp-L₁-mltG) grown in BHI to mid-exponential phase (OD₆₂₀ ≈0.15). Numbers on top of panels indicate stage of cell division (see text and Experimental details). The last row shows superimposed images from the two fluorescent channels, with overlapping signals shown as yellow. Scale bar (top left image) = 1 μm. (B) Averaged images and fluorescence intensity traces. Cells were binned into division stages 1–4, and images of the indicated number of cells (n) from two experiments were averaged and quantified using the graphical user interface program (GUI) described in Experimental procedures. Row 1, cell shapes from phase-contrast images; row 2, GFP-L-MltG fluorescent signal, row 3, FtsZ-L-RFP fluorescent signal and row 4, normalized average fluorescence intensity distributions along the horizontal cell axis for each channel (black, phase; green, MltG; red, FtsZ). (C) Representative growth curve of strains IU1824 (wild-type parent), IU9148 (ftsZ-L₂-mKate2), IU10228 (gfp-L₁-mltG), and IU10353 (ftsZ-L₂-mKate2 gfp-L₁-mltG). (D) Scatter plot of GFP-L-MltG versus FtsZ-L-RFP width at midcell equators and septa of cells in division stages 1 to 3 in (B). Labeled midcell widths were quantified using the GUI program (see Experimental procedures). The dotted reference line (same width of each protein) has slope = 1 and intercepts the origin. For statistical analysis, differences between the midcell widths of MltG and FtsZ were calculated for each cell in each division stage, and a one-sample t test (GraphPad Prism) was performed to determine if differences are significantly different from 0. ***, p<0.001. Data in (B) and (D) were from two independent biological replicates.