Figure 4. Growth rate vs age obtained from experiments: Growth rate vs age plots are shown for E. coli experimental data.

The red dots correspond to the binned data trends showing the variation in growth rate. The medium in which the experiments were conducted are (A) Alanine ($⟨T_d⟩$ = 214 min) (B) Glycerol ($⟨T_d⟩$ = 164 min) (C) Glucose-cas ($⟨T_d⟩$ = 65 min). The error bars show the standard deviation of the growth rate in each bin scaled by $\frac{1}{\sqrt{N}}$, where N is the number of cells in that bin. The dashed vertical lines mark the age at initiation of DNA replication (left line) and the start of septum formation (right line). In case of glucose-cas, the initiation age is not marked as it occurs in the mother cell.

Figure 4—figure supplement 1. Growth rate vs age curves extended beyond the division event.

(A,B,C) The binned growth rate trend is shown in red as a function of age for E. coli experimental data. The trends are obtained using the cell size trajectories extending beyond the division event (age >1). The plots are shown for (A) Alanine medium (N = 720 cells) (B) Glycerol medium (N = 594 cells). (C) Glucose-cas medium (N = 664 cells). The error bars in all three plots represent the standard deviation of the growth rate in each bin scaled by $\frac{1}{\sqrt{N}}$, where N is the number of cells in that bin. The growth rate trend appears to be periodic in each of the growth media that is, $\lambda$ at age ≈one is close to $\lambda$ at age ≈ 0. These trends agree with that of Figure 4 in the appropriate age ranges. (D) Simulations are carried out for N = 2500 cell cycles. The cell size trajectories are collected beyond the division event (age >1). The binned data trend for growth rate vs age plot is shown as purple circles for exponentially growing cells following the adder model. We observe the trend to be nearly constant as expected for exponential growth. The binned growth rate trend is also found to be nearly constant for the simulations of exponential growing cells following the adder per origin model (shown as magenta diamonds). (Inset) Shown as green squares is the elongation speed vs age plot for simulations of N = 2500 cell cycles of linearly growing cells following the adder model. As expected for linear growth, the binned elongation speed trend remains approximately constant with age. The growth rate trends for the models with exponential growth agree with that of Figure 3B. The elongation speed trend (inset) also agrees with the trend in Figure 3—figure supplement 3.

Figure 4—figure supplement 2. Inspection bias in the growth rate vs time from constriction plots obtained from experiments.

(A,C,E) The binned growth rate trend is shown in red as a function of time from the onset of constriction (t-$T_n$). Time t- $T_n=$ 0 corresponds to the onset of constriction for all cells considered. The plots are shown for (A). Alanine medium. (C) Glycerol medium. (E) Glucose-cas medium. The error bars in all three plots represent the standard deviation of the growth rate in each bin scaled by $\frac{1}{\sqrt{N}}$, where N is the number of cells in that bin. (B,D,F) The average generation time for the cells present in each bin of (B) Alanine medium (A) (D) Glycerol medium (C) (F) Glucose-cas medium (E) are shown. The vertical dashed lines represent the time range within which the average generation time remains approximately constant. The growth rate trends within this time range are consistent with that in Figure 4 for the respective growth condition as there is negligible inspection bias.