Speaker: Allyson Sgro (HHMI Janelia Research Campus)
Title: Understanding the emergence of microbial collective behaviors
Abstract: Groups of cells of all kinds work together as part of multicellular behaviors ranging from collective migration to development. These behaviors are coordinated at the level of single cells, where information about other cells and the environment are encoded in intracellular signaling dynamics that then drive cellular-level behaviors. We face two challenges in understanding how these complex behaviors are coordinated. First, linking these signals and cellular-level behaviors to observed population-wide behaviors is challenging because it requires bridging size- and time-scales. Second, because behaviors are coordinated via information cells can sense locally and this information is shaped by their environments, it is important to interrogate these behaviors in their natural contexts.
To address these challenges, we focus on a cellular slime mold, Dictyostelium discoideum, that uses a biochemical environmental signal during starvation to coordinate aggregation into multicellular groups for continued survival. To better understand the signaling dynamics required for coordinating behavior, we take a joint theory-experiment approach where we interrogate mathematical models of how these biochemical signaling dynamics could potentially drive coordinated behaviors with experimental data. Our work suggests several key features of signaling networks are important to robustly coordinate collective multicellular behaviors. To identify how natural environments shape coordination and thus behaviors, we have designed a naturalistic soil model environment where we can visualize how environments interact with different types of cells to affect collective outcomes. Our current findings suggest that the single-cell and population-wide signaling behaviors that coordinate development are robust in highly complex, three-dimensional environments, and that there are also other important cellular properties we do not yet fully understand required for success in nature.