Media, bacterial strains, and plasmids.

Cells were grown in lysogeny broth (LB; 1% tryptone, 0.5% yeast extract, 0.5% NaCl ± 1.5% Bacto agar) at 30°C, unless indicated otherwise. The antibiotic concentrations used were tetracycline (Tet), 5 μg/ml; ampicillin (Amp), 50 μg/ml; chloramphenicol (Cam), 25 μg/ml; and kanamycin (Kan), 25 μg/ml. The bacterial strains and plasmids used in this study are listed in Tables S3 and S4, respectively. A description of their construction and a list of the primers used (Table S5) are included in the supplemental material. All deletion strains used were obtained from the Keio knockout collection (47) and confirmed by sequencing.

We purchased A22 [S-(3,4-dichlorobenzyl)isothiourea HCl] from Calbiochem. We purchased compound 1 (catalog no. PH000337; 2,4-dichlorobenzyl imidothiocarbamate), compound 9 (152811; 3,4-dichlorophenylhydrazine HCl), compound 11 (T165948; 4-fluorobenzyl imidothiocarbamate HBr), compound 20 (MP265, PH012544; 4-chlorobenzyle imidothiocarbamate HCl), and compound 22 (T282057; 2-chlorobenzyl imidothiocarbamate) from Sigma. We purchased compound 4 (DP01615; 2,4-dichlorobenzyl butylamine) and compound 21 (S01620; 3-chlorobenzyl imidothiocarbamate) from Maybridge via Fisher Scientific. We purchased compound 10 [3-(3,4-dichlorophenyl)propan-1-amine], compound 19 (Z18380660), compound 23 ([(4-nitrophenyl)methyl]sulfanyl}methanimidamide HCl), and CBR-4830 (EN300-214505) from Enamine. We verified the purchased compounds via liquid chromatography-mass spectrometry (LC-MS). All compounds were dissolved in DMSO (J. T. Baker) to 10 mg/ml or the highest obtainable concentration below 10 mg/ml and stored at −20°C.