Microorganisms take in nutrients and grow while leaking many metabolites into the environment.Not only poisons and garbage unnecessary for cell growth, but also metabolites essential for cell growth are leaked.This appears to be detrimental to the cells, but it remains unclear why the cells did not evolve to prevent the leakage of essential metabolites.

　The research group expressed the state of the cell as the concentration of the internal chemical component group, and formulated a dynamical system model in which the state changes with time due to the chemical reaction, leakage of the chemical component, and concentration dilution accompanying volume growth.The effect of leakage of chemical components on the growth rate of cells in the steady state was simulated by computer.

　As a result, it was found that when there is a polymorphic reaction such as a catalytic reaction in the chemical reaction network inside the cell, even if a certain metabolite is essential for cell growth, its leakage can increase the growth rate.In addition, "flux control of multi-body reaction" in which when one reactant leaks, the rate of another chemical reaction increases relatively, and "balance between growth and dilution" regarding the balance between chemical reaction and concentration dilution associated with biomass production. We have clarified two mechanisms to increase the growth rate called "control".

　Since the leaked essential metabolites are also useful for other cell types, it is useful for the exchange of leaked metabolites among many cell types and for elucidating the origin of diversity and symbiosis of microbial ecosystems.In addition, the mechanism of growth promotion by leakage of metabolites is expected to be widely applicable to biological and social systems due to the general properties of growing systems such as cells.

Paper information:[Physical Review Letters Advantage of leakage of essential metabolites for cells