Fig. 4: Biochemical screening reveals that glutamate supplementation reduces the strength of cooperative growth.
From: Cooperative growth in microbial communities is a driver of multistability
a Subset of molecules used to supplement BHI in which focal species were inoculated at low population density (104 CFU/mL). Heatmap shows the fold growth (OD24h/OD0h, n = 3) in supplemented BHI and control (BHI only, bottom); glutamate (dashed borders) markedly increases the fold growth of all species with cooperative growth dynamics, allowing for Mc’s growth even below its survival threshold (105 CFU/mL). Maximum fold growth is scaled for each column relative to monoculture of the indicated species. b Effect of glutamate supplementation on the growth dynamics of each focal species at different initial population densities. Panels show per capita growth rates as a function of the initial population density in BHI (empty dots) and BHI supplemented with glutamate (filled dots) at 100 mM, which is the dose that produced maximum fold-growth in a dose-response assay (Supplementary Fig. 8). Cn maintains its logistic growth pattern irrespective of glutamate supplementation, whereas Sa and Se adopt an analogous, monotonically decreasing growth pattern upon elimination of the weak Allee effect. Glutamate supplementation also lowers the survival threshold of Mc. Error bars are the standard error (SE) across replicates, n = 3.
