Episode Summary

Finally found some good stories, so we're back! This episode: How slime molds encode and use memories built into their own bodies!

Microbe of the episode

Microbe of the episode: Aeromonas salmoncida

Jesse's takeaways

Despite being single-celled organisms, slime molds have fairly complex behavior, including a basic form of memory. They often grow as a network of tubes of cytoplasm branching out from one place to find and exploit new sources of food in their environment. When these tubes connect to new food, other less productive branches of its body shrink away.
As it turns out, this body form serves a role in memory also. This study determined that the slime mold's tubes undergo constant squeezing, which moves cell contents around and also shrinks them. When tubes are connecting to a food source though, they secrete a softening agent that allows the pressure to expand the tubes instead of shrinking them. These larger tubes consequently are capable of transporting more softening agent farther away to newer food sources, so the history of food discoveries is recorded in the slime mold's own body, which also influences its responses to new discoveries.


Researchers find a single-celled slime mold with no nervous system that remembers food locations

Journal Paper

Kramar M, Alim K. 2021. Encoding memory in tube diameter hierarchy of living flow network. Proc Natl Acad Sci 118.

Other interesting stories

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Porous interior of bone