a mechanism for memory transfer between individuals in C. elegans

IN earlier work, Murphy's lab discovered that mother worms who are sickened by P. aeruginosa learn to avoid the bacterium, and that they can impress this avoidance behavior upon their offspring for the next four generations. Mother worms who've eaten P. aeruginosa absorb a bacterial small RNA called P11 through their intestines, which touches off a signal in the worm's germ line reproductive cells that is then transmitted to a neuron that controls behavior. Afterwards, the new behavior is conveyed to future progeny via changes made to germ line cells.

"We found that one worm can learn to avoid this pathogenic bacterium and if we grind up that worm, or even just use the media the worms are swimming in, and give that media or the crushed-worm lysate to naïve worms, those worms now 'learn' to avoid the pathogen as well," explains Murphy.

This finding suggests that worms secrete some signal that, when picked up by other worms, can modify their behavior. Interestingly, the progeny of worms "educated" by receipt of this signal also avoid pathogenic P. aeruginosa for the following four generations. This suggests that the secreted signal touches off the same learning pathway in recipient worms as in those directly exposed to the pathogen. Murphy's group sought to identify the secreted signal.

"What we discovered is that a retrotransposon called Cer1 that forms viral-like particles seems to carry a memory not only between tissues (from the worm's germline to its neurons) but also between individuals," says Murphy.

https://phys.org/news/2021-09-scientists-mechanism-memory-individuals-elegans.html