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CAMP Seminar: Adaptive regulation of bacterial cell size and division cycle

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Shiladitya Banerjee, University College London
29 January 2018 from 3:30 PM to 4:30 PM
339 Davey Laboratory
Contact Name
Reka Albert
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How cells coordinate growth and division to maintain a narrow size distribution within a species population is a longstanding question. Recently, evidence has emerged that Escherichia coli and a number of other unicellular organisms divide when their size increments by a fixed amount, but the physical origins of this incremental rule for size control have remained elusive. In this talk I will discuss my recent work that integrates single-cell imaging experiments and theoretical modelling to demonstrate that bacteria maintain size homeostasis through two distinct phases of growth: a phase in which cells uniformly add new cell wall material for a fixed duration, followed by a second phase in which new growth localizes to the division plane, leading to a constant size increment. This mechanism is conserved across a wide range of growth conditions, allowing cells to adapt their size and shapes to environmental variations. In particular, my results show that in response to antibiotic stresses, bacteria adapt their division cycle to increase fitness by altering their surface-to-volume ratio. This suggests a novel mechanism of drug resistance by mechanical feedback, motivating further investigation of the molecular regulations of cellular shape, size, and division.