[SMaLS] Death and chemotaxis: Watching bacterial collectives navigate complex environments

Speaker: Prof. Sujit Datta (Caltech)

Title: Death and chemotaxis: Watching bacterial collectives navigate complex environments

Abstract: Bacteria in nature inhabit complex, crowded environments like soils, sediments, and biological gels. However, lab studies typically focus on cells in bulk liquid. How do environmental complexities shape bacterial behavior? And how is this behavior altered when bacteria encounter viral predators? In this talk, I will describe my group's work addressing these questions using tools from soft matter, 3D imaging, and biophysical modeling. We have developed the ability to directly visualize bacteria from single cells to entire migrating collectives and 3D-print precisely structured collectives in crowded environments that mimic natural soils. I will describe how confined bacteria exhibit hopping-and-trapping motility, how collectives form traveling fronts by processing and following chemical cues (a process known as chemotaxis), and how this collective chemotaxis autonomously stabilizes the migrating front against perturbations. Strikingly, we find that chemotaxis also enables bacterial collectives to outrun viral predators—escaping annihilation not through evolution of resistance, but through speed. Together, these results highlight how chemotaxis enables bacterial collectives to translate local chemical information into robust, large-scale collective resilience.