Presenter: Henry Mattingly, Ph.D., Yale University
Topic: How do inferences shape functions in biology?
Organisms’ survival depends on their abilities to sense the environment and act appropriately. To what extent does incomplete information limit and shape the functions of biological systems? Past studies have used information theory to quantify how well organisms make inferences, but few have connected those inferences to actions. I will talk about a recent project in which we have made progress on this question, using Escherichia coli chemotaxis as a model system. First, we found that the rate at which an E. coli bacterium acquires information about its environment sets a theoretical upper limit on how fast it can climb a chemical gradient. Then, we experimentally measured information transfer by the chemotaxis signaling pathway using a single-cell FRET reporter, and we measured how fast cells climb gradients. We found that E. coli cells get much less information to make behavioral decisions than previously thought. Despite this, they use this little information efficiently, climbing gradients at speeds that are within a factor of two of the theoretical limit. These results demonstrate that information can be a limited resource for performing biological functions. This in turn suggests that normative theories about how to best use information may be powerful tools for understanding the design of sensing and response systems in biology, beyond bacteria.