How Bacteria Maintain Size Homeostasis

Abstract: We discovered the ‘adder’ principle of size homeostasis in bacteria in 2012 and reported extensive supporting data last year. The adder principle states that cells add nearly constant size between birth and division irrespective of the size at birth. This simple but counter-intuitive mechanism overturns the 50-year old sizer and timer paradigm in cell size control. I will discuss how we discovered adder, how general it is, and what we do and do not understand.

Bio: I am a theoretical physicist by training, leading an experimental quantitative biology laboratory since 2007. The first phase of my lab was at Harvard University, where I was a Bauer Fellow from 2007 to 2012. I moved my lab to UCSD in 2012 to join the campus-wide initiative in quantitative biology. While my career path from theoretical physics to experimental biology may seem unusual, running through every choice I made thus far is my desire to understand how one cell becomes two cells. In research, I aim at principles of basic cellular reproduction, as did the pioneers in the first golden era of microbial physiology from the 1940s to 1960s. I use mainly a model organism Escherichia coli to answer fundamental, often long-standing biological questions.