Schematic drawing of plasmid pML1 and construction of plasmid pSNUCIQ3. Plasmid pML1, encoding the lysis protein E, and plasmid pSNUCIQ3, encoding SNUC, were used for the coexpression of gene E and SNUC in E. coli O157:H7. The expression of the killing genes was triggered either by the addition of a chemical inducer (pSNUCIQ3) or by a thermal shift from 28°C to 42°C (pML1). E, lysis gene E; Amp, ampicillin resistance gene; Kan, kanamycin resistance gene; Tet, tetracycline resistance gene; ColE1 and p15A, origins of replication; A1-O4/O3, synthetic, chemically inducible promoter; PRMand PR, rightward “maintenance” and rightward promoters of bacteriophage lambda, respectively; cI857, gene encoding the thermosensitive repressor for the lambda PR promoter; lacIq, gene encoding the repressor for the synthetic A1-O4/O3 promoter; XhoI, PstI, and SalI, restriction sites used for the construction of pSNUCIQ3.