Event description
In this talk, I will walk through my journey from studying the physiology of individual bacterial cells to exploring how these cells interact and form complex communities. My early work focused on how bacteria regulate growth and internal organization—particularly how they make decisions in processes such as chemotaxis and cell division. Over time, my
interests shifted toward understanding what happens when bacteria do not act in isolation: how they interact, share resources, and collectively respond to their environment.
I will present our current work on understanding and predicting cross-feeding interactions between bacterial cells under varying environmental conditions. Many natural bacterial isolates are auxotrophs—unable to produce certain amino acids—and must rely on neighboring cells for these essential building blocks. This exchange, known as crossfeeding,
is thought to occur through leakage from partner cells. However, how these interactions are maintained in dynamic environments, and what roles different cell types play, remains poorly understood. To address these questions, we adopted a bottom-up approach using simplified consortia of bi- or uni-directional cross-feeding auxotrophs in spatially structured systems. By coupling single-cell microfluidics experiments with mathematical modeling, we tracked growth dynamics in space and time. We found that cross-feeding interactions are highly localized, and that small subsets of cells can drive the resumption of growth in fluctuating environments. Our models also predict how these interactions are modulated under sublethal levels of antibiotics, offering insight into the conditions that foster microbial cooperation.
I will conclude by outlining how single-cell microfluidics and systematic characterization of bacterial responses to host-derived molecules can shed light on microbe–host ecological dynamics. As a case study, I will focus on the bile acid cycle, where microbial transformations of host-produced molecules may act as a form of chemical communication—shaping both microbial communities and host physiology.