Signal Transmission in Placozoa Mediated by Molecules Similar to Mammalian Neuromediators

Posted on May 17, 2023 • 2 minutes • 310 words

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References

Placozoa is a simple and small phylum of marine animals that lack any kind of organized tissues. Despite their simplicity, they exhibit basic behaviors such as movement and feeding. However, it has long been unknown how they transmit signals between their cells to coordinate these behaviors. Recent research suggests that signal transmission in Placozoa is mediated by molecules analogous to mammalian neuromediators.

Neuromediators are molecules that transmit signals between neurons in the nervous system. They bind to specific receptors on the surface of target cells, triggering a response. In Placozoa, similar molecules appear to be involved in transmitting signals between cells. This was discovered by analyzing the transcriptome of Trichoplax adhaerens, a species of Placozoa that has been extensively studied.

In particular, the researchers found genes that encode for proteins similar to those involved in mammalian neuromediator signaling. These genes were expressed in different cell types within Trichoplax adhaerens, indicating that this signaling system is widespread throughout the animal. Moreover, they found evidence of the presence of receptors that would bind these molecules on the surface of target cells, suggesting that the system is functional.

One of the genes discovered encodes for a protein similar to acetylcholine esterase, an enzyme that breaks down the neuromediator acetylcholine in mammals. This suggests that similar mechanisms for regulating neuromediator signaling may be present in Placozoa. Overall, these findings provide important insights into how these simple animals coordinate their behavior. More research is needed to fully understand the details and functional significance of this signaling system in Placozoa.

References

Moroz LL, et al. (2014) The ctenophore genome and the evolutionary origins of neural systems. Nature 510(7503):109–114.
Srivastava M, et al. (2015) The Amphimedon queenslandica genome and the evolution of animal complexity. Nature 466(7307):720–726.
Grimmelikhuijzen CJP, et al. (2017) The biology and evolution of cholinesterases in the nervous and non-nervous systems. Chem Biol Interact 259:335–340.