TABLE 1.
Bacterial strains and plasmids used
| Strain or plasmid | Description | Source or reference |
|---|---|---|
| Strains | ||
| Sakai 813 | Isogenic stx1 and stx2-negative nontoxigenic derivative of the Sakai strain; contains insertion of kanamycin resistance gene into stxA2 gene and has deletion of 624-bp BsiWI fragment encompassing the start of the stxA1 gene and the 5′ flanking region | Chihiro Sasakawa |
| LZ1 | ygeH deletion mutant of Sakai 813 | This study |
| LZ2 | etrA deletion mutant of Sakai 813 | This study |
| LZ3 | eivF deletion mutant of Sakai 813 | This study |
| 193 Nalr | Spontaneous nalidixic acid-resistant mutant of recent bovine EHEC O26:H- isolate from the United Kingdom | This study |
| Plasmids | ||
| pKD46 | For deletion mutagenesis; encodes lambda Red genes | 11 |
| pKD3 | For deletion mutagenesis; template plasmid | 11 |
| pCP20 | For deletion mutagenesis; encodes FLP recombinase | 11 |
| pBAD30 | Low-copy-number expression vector with arabinose-inducible promoter | 20 |
| pBADetrA | etrA cloned into pBAD30 | This study |
| pBADeivF | eivF cloned into pBAD30 | This study |
| pAJR71 to pAJR75 | GFP fusion plasmids with promoters from LEE-1 to LEE-5 operons cloned in frame 5′ to the gene amplified from enhanced half-life GFP vector peGFP (Clontech, Ltd., Basingstoke, United Kingdom) | 48 |