Event

Spatial organization in living systems is crucial for their functioning and is typically achieved in complex environments—from molecular processes in the crowded cytoplasm to microbial collectives growing in structured habitats. In the first part of my talk, I will discuss how bacterial colonies self-organize and acquire their shape in 3D complex environments. While laboratory studies of bacteria in well-mixed cultures or flat colonies have provided valuable insights into bacterial cellular processes, they fail to capture the spatial arrangements found in natural settings, such as soils and hosts. As a result, how colonies grow and function in these 3D environments remains largely unknown, despite their prevalence in nature. By integrating experiments with biophysical modeling, I will show how colonies growing in 3D transparent granular environments develop architectures—driven by differential access to nutrients—that fundamentally differ from their flat-culture counterparts and are generic across species and environmental conditions.

In the second part of my talk, I will shift focus to biomolecular phase separation into condensates—an emerging mechanism for intracellular organization. Although condensate size is often crucial for biological function, the mechanisms governing size regulation and self-organization remain elusive. Using the algal pyrenoid—a condensate that mediates one-third of global CO₂ fixation—as an experimental model, I will highlight general biophysical principles that control condensate size through active mechanisms—observed in vivo here for the first time—and discuss their implications for how cells spatially organize their materials and functions.

 Taken together, these findings reveal new principles for predicting and controlling the organization, shape, and size of living systems in complex, crowded environments across scales.