Interface-mediated three-dimensional microbe expansion

Microbe expansion such as bacterial swarming is commonly found at the interface. Usually, the expansion occurs in a quasi-two-dimensional scenario. However, it is less known that how the microbes expand into the third dimension. Here, we study a recently discovered mode of vertical growth of bacterial colonies termed as “active interface bulging” (Ref: Liu, Siyu, et al. "Active bulging promotes biofilm formation in a bacterial swarm." bioRxiv (2022): 2022-08.). We characterized the growth and interaction dynamics of this unique process by high resolution imaging. Our findings shed light on microbe expansion and biofilm formation.