Growing fast or adapting quickly?
A recent Nature paper from the Basan, Hwa, Paulsson, and Sauer labs reports how rapid microbial growth in one condition compromises the ability to quickly switch to new conditions. This remarkably conserved tradeoff emerges directly from the biochemistry of central metabolism and can mathematically predict broadly disparate growth rates on different substrates.
Optimal rapid growth requires maximal fluxes through pathways, but what if microbes need to adapt to a new condition? When switching from hexoses to organic acids, the massive flux through glycolysis must be reverted, but like Sisyphus every molecule pushed “uphill” in the gluconeogenic direction comes down again because glycolytic enzymes are still abundant. Metabolomic analysis revealed this struggle in which long lags result from a series of low metabolite pools before eventually growth resumes. The study found a conserved tradeoff across dozens of conditions and in different species where exceptionally fast growing microbes were terrible at switching between conditions and vice versa. This remarkably conserved tradeoff emerges directly from the biochemistry of central metabolism and its mathematical description enables quantitative predictions of optimal growth rates for which the time spent on growth and lag is balanced and minimized. This model provides a unique perspective on the notorious problem of why bacteria grow on different substrates at broadly disparate rates.
Link to the paper in external page "Nature"