Overproduction of FzlA hyperactivates constriction. (A) Representative phase-contrast time-lapse microscopy of a WT constricting Caulobacter cell. The timepoints of constriction initiation and completion are denoted. Scale bars, 2 µm. The orange lines represent measures of length or width for each cell. Ti: Time of initiation. Tf: Final timepoint of constriction. (B–E) Superplots comparing the (B) constriction rate (P = 0.1058, one-tail t test), (C) elongation rate (P = 0.2197, one-tail t test), (D) ratio of constriction to elongation rate (P = 0.0493, one-tailed t test), or (E) time to constriction initiation for strains harboring either an EV (EG1644) control or fzlA overexpression (OE; EG3637) construct (P = 0.6, Kolmogorov-Smirnov test). The strains were induced with 0.3% xylose for 1 h prior to and throughout the time-lapse experiment. Each circle is the value of a single cell, while the large squares are the average of a biological replicate. The bar is the average of the three means and statistics were performed using the means of the three biological replicates. EG1644—replicate 1, 67 cells; replicate 2, 63 cells; replicate 3, 54 cells. EG3637—replicate 1, 60 cells; replicate 2, 40 cells; replicate 3, 55 cells. *P < 0.05.
