Scientists have discovered that choanoflagellates coordinate their movements through electrical signals from voltage-gated calcium channels, providing important insights into multicellularity and the early evolution of the nervous system. A recent study published in Science Advances provides compelling evidence for the existence of electrical signaling and coordinated behavior in choanoflagellates. The discovery sheds light on the early evolution of multicellular communication and the origins of animal nervous systems.
Researchers from Burkhardt's group at the Michael Sass Center at the University of Bergen have discovered that there is significant behavioral diversity in the rosette-shaped colonies of the choanoflagellate Salpingoecarosetta, and these little creatures have more surprises hidden.
"We discovered communication between colony cells that regulates the shape of the entire rosette and the beating of cilia," explains first author Jeffrey Colgren. "We had no clear expectations before we put the cultures under the microscope, but when we put the cultures under the microscope we were very excited."
Multicellularity is a defining characteristic of all animals, allowing animals to interact with their environment in unique ways by integrating input from highly specialized cell types such as neurons and muscle cells. For flagellate-like organisms found in marine and aquatic environments around the world, the line between unicellular and multicellular is less clear-cut.
Some species, including S. rosetta, exhibit complex life cycles that include colony stages. Although communities form through cell division, much like developing animal embryos, they lack specialized cell types and are more similar to a group of individual cells than a cohesive organism.
Pawel Burkhardt, the last author, said: "S. rosetta is a powerful model for studying the emergence of multicellularity during animal evolution. Our study reveals that groups of choanoflagellates coordinate their movements through shared signaling pathways, which provides fascinating insights into early sensory-motor systems."
The team used a newly developed genetic tool to visualize calcium activity in S. rosetta cells and found that the cells synchronized their behavior through voltage-gated calcium channels, the same kind used by animal neurons and muscle cells.
"This evidence shows how information flows from cell to cell in a choanoflagellate community, suggesting that cell-cell signaling is going on fervently," Colgren said. "Astonishingly, this finding shows that the ability to coordinate movement at the cellular level predates the first generation of animals."
Going forward, the team plans to further investigate how signals propagate between cells and whether similar mechanisms exist in other algae. "The tools and findings developed in this study raise many interesting new questions," Kolgren concluded. "We're really looking forward to seeing where we and others go in the future."
Compiled from /scitechdaily