2 research outputs found
Effects of molecular noise on cell size control
Cells employ control strategies to maintain a stable size. Dividing at a
target size (the `sizer' strategy) is thought to produce the tightest size
distribution. However, this result follows from phenomenological models that
ignore the molecular mechanisms required to implement the strategy. Here we
investigate a simple mechanistic model for exponentially growing cells whose
division is triggered at a molecular abundance threshold. We find that size
noise inherits the molecular noise and is consequently minimized not by the
sizer but by the `adder' strategy, where a cell divides after adding a target
amount to its birth size. We derive a lower bound on size noise that agrees
with publicly available data from six microfluidic studies on Escherichia coli
bacteria.Comment: 10 pages, 3 figure
Multigenerational memory in bacterial size control
Cells maintain a stable size as they grow and divide. Inspired by the
available experimental data, most proposed models for size homeostasis assume
size control mechanisms that act on a timescale of one generation. Such
mechanisms lead to short-lived autocorrelations in size fluctuations that decay
within less than two generations. However, recent evidence from comparing
sister lineages suggests that correlations in size fluctuations can persist for
many generations. Here we develop a minimal model that explains these seemingly
contradictory results. Our model proposes that different environments result in
different control parameters, leading to distinct inheritance patterns.
Multigenerational memory is revealed in constant environments but obscured when
averaging over many different environments. Inferring the parameters of our
model from bacterial size data in microfluidic experiments, we recapitulate
observed statistics of homeostasis and phenotypic inheritance. Our work
elucidates the impact of the environment on cell homeostasis and growth and
division dynamics.Comment: 17 pages, 8 figure