Self-organized canals enable long range directed material transport in bacterial communities

Abstract

Long-range material transport is essential to maintain the physiological functions of multicellular organisms such as animals and plants. By contrast, material transport in bacteria is often short-ranged and limited by diffusion. Here we report a unique form of actively regulated long-range directed material transport in structured bacterial communities. Using Pseudomonas aeruginosa colonies as a model system, we discover that a large-scale and temporally evolving open channel system spontaneously develops in the colony via shear-induced banding. Fluid flows in the open channels support high-speed (up to 450 µm/s) transport of cells and outer membrane vesicles over centimeters, and help to eradicate colonies of a competing species Staphylococcus aureus. The open channels are reminiscent of human-made canals for cargo transport, and the channel flows are driven by interfacial tension mediated by cell-secreted biosurfactants. The spatial-temporal dynamics of fluid flows in the open channels are qualitatively described by flow profile measurement and mathematical modeling. Our findings demonstrate that mechanochemical coupling between interfacial force and biosurfactant kinetics can coordinate large-scale material transport in primitive life forms, suggesting a new principle to engineer self-organized microbial communities.

Active bulging promotes biofilm formation in a bacterial swarm

“…More recently, mechanical forces at the interfaces are expected to play crucial roles in the surface-associated life of microbial communities (14)(15)(16)(17). For instance, cell-substrate mechanical interaction drives biofilm morphogenesis and orientational ordering of cells (18,19); while surface flows have been shown to promote the expansion (20)(21)(22)(23)(24)(25) and material transport (26) within bacterial colonies. However, it remains largely unexplored how the physical environment of interfaces may contribute to more diverse processes involved in the development and behavior of surface-associated microbial communities.…”