Thanks Greg!

Wouldn't have happened without the support of @saramitri.bsky.social and crucial contributions from @juliensluneau.bsky.social @andrewhq9.bsky.social @pengellab.bsky.social + Gunn, Eric, Maggie and Alisson

Thanks to @snf-fns.ch and others for funding :)

These findings raise many new questions (to us) and has changed how we think about the emergence of cross-feeding interactions.

Metabolite release rates are sensitive to changes in intracellular metabolism, suggesting that metabolism is optimized on the network level to use, reuse and retain metabolites proportionally to their relative value. Retaining or reusing "cheap" metabolites might not be worth the investment.

Also, the value of a metabolite is more important than any other factor in explaining variability in release rates

Across the board we find such a correlation. The only real exception is an engineered strain.

Here we propose and test the hypothesis that metabolite release generally constitutes a fitness cost that microbes have evolved to reduce. If this is true -> release of high-value metabolites should be more strongly selected against compared to low-value metabolites