Fig. 3: Phenylobacterium immobile reproduces symmetrically.
a Micrographs from timelapses at the time of the first and second cell division events for Caulobacter crescentus CB15 (PYE, 30 °C), P. immobile ET (R2A, 30 °C), and Escherichia coli MG1655 (LB, 37 °C). Cell outline schematics highlight daughter cell lineages. Full timelapses are shown in Supplementary Movies 1–3. Scale bars: 1 µm. b Schematics of the quantification of degrees of replicative asymmetry from time-lapse microscopy. The daughter cells of an initial binary cell division event divide again after the times t1 and t2, respectively. For bacteria with replicative asymmetry among daughter cells, one daughter cell undergoes subsequent cell division at a later time point (t2), than its sibling (t1), i.e., ∆t = t2 − t1 > 0. To compare species with different growth rates, we defined the degree of asymmetry as ∆t / t2, i.e., how much extra time the late-dividing daughter cells spends to divide, as a proportion of their total generation time. c Histograms of degrees of asymmetry calculated for daughter cell pairs as described in (b), from time-lapse experiments conducted as in (a) for C. crescentus, P. immobile, and E. coli in at least three biologically independent replicates (in total n = 433, n = 473, and n = 207 daughter cell pairs, respectively). The right-most bins represent degrees of asymmetry above 50%. Source data are provided as a Source Data file. d Histograms of generation times of individual cells, from daughter cell pairs analyzed in (c). For C. crescentus CB15, the approximate time difference between the bimodal peaks is highlighted. The right-most bins represent generation times above 150 min for C. crescentus and E. coli, or above 20 h for P. immobile. Source data are provided as a Source Data file. e Histograms of relative cell constriction site positions in C. crescentus NA1000 (n = 1900), P. immobile ET (n = 1900), and E. coli MG1655 (n = 1200), divided into 100 bins, quantified from snapshot images of cells grown in batch cultures to mid-exponential phase under growth conditions corresponding to those used for timelapses presented in (a). Vertical lines show mid-cell position ±5%. Schematic cell illustrations highlight that relative constriction site positions are not sorted by cell polarity. Source data are provided as a Source Data file.
