Phenotypes caused by toxins and their cognate antitoxins in E. coli. (A) The toxic effect of nine toxins of Bosea sp. PAMC 26642 on E. coli growth. E. coli BL21(DE3) cells transformed with pBAD33 or pBAD33-toxin were spotted on M9 agar plates supplemented with or without 0.1% arabinose, followed by incubation at 37°C or 18°C. C indicates pBAD33. (B) Neutralization of toxin effects by antitoxin expression. E. coli BL21(DE3) cells transformed with pET21c or pET21c-antitoxin were spotted on M9 agar plate supplemented with or without both arabinose and IPTG, and the plates were incubated at 37°C or 18°C. A; cells with pBAD33/pET21c, B; pBAD33-toxin/pET21c, C; pBAD33/pET21c-antitoxin, and D; pBAD33-toxin/pET21c-antitoxin.
