Noise signature in added size suggests bacteria target a commitment size to enable division

Abstract

Recent experiments suggested that sizer-like division strategy, a deviation from the adder paradigm might be produced by additional degradation events of cell division machinery molecules. We revisited single cell size data from a recently microfluidics setup using the above model. We observed that such additional degradation process, although reproduces size observations in the mean sense, it is unable to capture cell size fluctuations. We further extended recently proposed power law models to include commitment size. Our proposal is in agreement of both mean and fluctuation profiles seen in experiments. Our approach suggests further uses of noise profiles on dissecting cell size regulatory mechanisms. SIGNIFICANCEWe contrast cell division models against bacteria cell size data in minimal media. Our results seems to support the idea that division starts once bacteria meet a given commitment size.