Table 1 List of bacterial strains and plasmids used in the present study.
Bacteria/plasmid | Genotypic characteristics | References |
|---|---|---|
S. Typhimurium | ||
 JOL401 | Wild-type (WT) | Lab stock |
 JOL911 | Δlon, ΔcpxR | [13] |
 JOL2500 | Δlon, ΔcpxR, ΔsifA, Δasd | [15] |
 JOL3000 | Δlon, ΔcpxR, ΔrfaL, ΔpagL::lpxE,Δasd | Lab stock |
 JOL2782 | JOL2500 carrying pJHL204-H1N1 HA | In this study |
 JOL2837 | JOL3000 carrying pJHL204-H1N1 HA | In this study |
E. coli | ||
 DH5α | E. coli F−Φ80dlacZΔM15Δ (lacZYA-argF) U169recA1 endA1 hsdR17(rk-mk+) phoA supE44 thi1 gyr A96 relA1λ- | Lab stock |
 BL21(DE3) | F–, ompT, hsdSB (rB–mB–), dcm, gal, λ(DE3) | Lab stock |
 E. coli 232 | F—λ—φ80Δ(lacZYA-argF) endA1 recA1 hadR17 deoR thi-1 glnV44 gyrA96 relA1 ΔasdA4 | Lab stock |
 F. tularensis | Source for lpxE amplification | Lab stock |
Plasmid | ||
 pET28a( +) | IPTG-inducible expression vector; Kanamycin resistance | Novagen |
 pJHL204 | asd + , CMV promoter, SV40 promoter, pBR322 ori | Lab stock |
 pKD46 | Ori101-repA101ts; encodes Lambda red genes (exo, bet, gam); native terminator (tL3); arabinose-inducible for expression (ParaB);bla | [20] |
 pKD3 | oriR6K gamma, bla (ampR), rgnB (Ter), catR, FRT | [20] |
 pCP20 | Helper plasmid, contains a temperature-inducible flp gene for removing the FRT flanked chloramphenicol gene | [41] |