UC San Diego

Cells, the fundamental unit of life, exist in an ever-changing environment. The ability to sense the environment and decide on a suitable strategy is therefore one of the most important cellular functions. In this dissertation, I will describe two examples of signal transmission and processing that utilize ions. In Chapter 2, I will demonstrate how Bacillus subtilis cells self-organize to optimize longe-range signal transmission, in a striking example of statistical physics informing multilevel cellular behavior. In Chapter 3, I will show how B. subtilis spores use stored ions to integrate external signals to decide whether to revive from dormancy. Taken together, these examples show the integral role of ions in biological signaling: weaving communication wires that span thousands of cells, and working to reignite life from a complete stop.