Bacterial Cultivation and Citrate Utilization

All bacterial strains (listed in Table S1 in the supplemental material) were cultured aerobically at 37°C unless stated otherwise in the particular section. Cells were cultured in lysogenic broth (LB) or on agar plates (LA) with the appropriate amount of the following antibiotic(s) or inducer when needed: carbenicillin, 100 μg/mL; tetracycline, 15 μg/mL; and 1 mM IPTG (isopropyl-β-d-thiogalactopyranoside; Sigma). To test for the ability to use citrate, we used modified Simmons’s medium, as previously described in reference 57 (link). One representative of three independent experiments is shown. Incubation in Koser’s citrate broth (Condalab) was done overnight, and where necessary, 0.1% glucose, 15 mM nitrate, and 15 mM fumarate were included. The citrate levels were measured with a citrate assay kit (Sigma-Aldrich), following the manufacturer’s instructions.