higBA loci and results showing HigB toxicity is masked by HigA. (A) The higBA operon of Pseudomonas aeruginosa
PA14. The toxin gene higB (not annotated, 5514513‐5514791) and the antitoxin gene higA (PA4674, PA14_61840, 5514196‐5514516) were unveiled using RASTA software. (B) Overnight cultures of strains of Escherichia coli
TG1/pCA24N (pCA24N, control), E. coli
TG1/pCA24N (lacZ) (pCA24N(lacZ), control), E. coli
TG1/pCA24N(His‐higB) (pCA24N(higB)), E. coli
TG1/pCA24N(higA‐FLAG) (pCA24N(higA)), E. coli
TG1/pCA24N(His‐higB‐higA‐FLAG) (pCA24N(higBA)), and E. coli
TG1/pCA24N(His‐higB‐higAX‐FLAG), where “X” indicates the translation start signal was changed to a threonine codon so antitoxin HigA is not produced (pCA24N(higBAX)), were inoculated into 25 mL of LB medium at an initial of turbidity of 0.05 at 600 nm at 37°C. IPTG (0.01 mmol/L) was added after 1 h. The error bars shown are standard deviation from three independent cultures.