L1 arrest

Hi everyone!
I made a bleaching synchronized with gravid worms to remove E. coli because I want to work with probiotic bacterias.
I discovered that the worms are arrested in L1 even if they are fed with the new bacteria. However, I did the same with E.coli and the worms grow.
How I can prevent the arrest in L1? Could worms not like new food?


Interesting. It sounds like the L1s are unable to eat the probiotic bacteria, or don’t recognize it as food. Maybe the cell size of the probiotic bacteria is too large for the small mouths of newly hatched L1s?

One obvious thing you might try would be to dope the probiotic bacteria with “dead” food - either E. coli that you’ve killed or axenic media? This could help if the L1s just need to get a bit bigger before they can eat the probiotic bacteria.

There are mutants that continue to pump their pharynx off of food, and so might conceivably eat even without recognizing the probiotic bacteria as food (or maybe drug treatments to achieve the same effect? it’s not something I’ve ever worked with), but that seems like a stretch. Cute if it worked, though.

One other possibility: maybe the “probiotic” bacteria are hostile to the worms? Have you tried feeding them killed “probiotic” bacteria? Mixing the “probiotic” with living E. coli (this is a bit problematic as it can change the behavior of both bacterial species)? Or, of course, this is a different reason to experiment with mixing the “probiotic” bacteria with killed E. coli or another adequate non-living food source.

Thanks for your answers, they have helped me to look for information and advance my studies.
I have searched for bibliography and in several studies of probiotics with elegans the worms grow with E.coli (dead or alive, depending on the article) up to the larval stage L4. In this larval stage, the worms transfer to the probiotic bacteria.

Thank you so much for the interest shown in this post.