Do you know: Small colonies of microbes communicate to coordinate their behavior
in 2025
A new study published in Scientific Progress shows evidence of electrical signaling and coordinated behavior in choanoflagellates, the closest living relatives of animals. This elaborate example of cell communication provides important insights into the early evolution of multicellular animals and nervous systems.
Researchers from Burkhardt’s group at the Michael Sars Center, University of Bergen, have revealed remarkable behavioral diversity within the rose-shaped colonies of the choanflagellate Salpingoeca rosetta — and the little organisms surprised them even more. “???????We found communication among the cells of the colonies, which controls the shape and ciliary beating throughout the rosette,” explains the first author Jeffrey Colgren. “We didn’t have clear expectations of what we would see in the cultures before putting them under the microscope, but when we did, it was very exciting.”
Multicellularity is a defining characteristic of all animals, enabling them to interact with their environment in unique ways by integrating the input of highly specialized cell types, such as neurons and muscle cells. For coanoflagellates, flagellated organisms found in marine and aquatic environments around the globe, the boundary between uni- and multicellular is not so distinct. Some species, including S.rosetta, show complex life cycles including colonial stages. Although the colonies are formed by cell divisions, like developing animal embryos, they lack specific cell types and are more like a group of individual cells than a cohesive organism. “S. rosetta is a powerful model for investigating the emergence of multicellularity during animal evolution,” says last author Pawel Burkhardt. “Since our study shows that colonial choanoflagellates coordinate their movements through shared signaling pathways, it provides great insights into early sensory-motor systems.”
Using a newly developed genetic tool that enables the visualization of calcium activity in S. rosetta, the team discovered that the cells synchronize their behavior through voltage-gated calcium channels, the same type of channels used by neurons animals and muscle cells. “This evidence of how information flows between cells in choanoflagellate colonies points to cell-cell signaling at the apex of multicellularity,” says Colgren. Significantly, the discovery suggests that the ability to coordinate movement at the cellular level predates the first animals.
Moving forward, the team plans to further investigate how signals propagate between cells and whether similar mechanisms exist in other choanoflagellate species. “The tools developed and the results of this study open up many new and interesting questions”,
Colgren concludes. “We’re excited to see where we and others take this in the future.”