TABLE 1.

Bacterial strains and plasmids used in this study

Strain or plasmidGenotype or relevant characteristicsSource or reference
Strains
    S. enterica serovar Typhimurium UK-1
    χ9241ΔpabA1516 ΔpabB232 ΔasdA16 ΔaraBAD23 ΔrelA198::araC PBAD lacI TT53
    χ9277χ9241 ΔsopB1925This study
    χ9373Δpmi-2426 Δ(gmd-fcl)-26 ΔPfur81::TT araC PBAD fur ΔPcrp527::TT araC PBAD crp ΔasdA21::TT araC PBAD c2 ΔaraE25 ΔaraBAD23 ΔrelA198::araC PBAD lacI TTLab collection
    χ9402χ9373 ΔsopB1925This study
    S. pneumoniae WU2Wild-type virulent, encapsulated type 32
Plasmids
    pMEG-375sacRB mobRP4 oriR6K; Cmr Apr8
    pYA3733pMEG-375 with ΔsopB1925 mutationThis study
    pYA3493Plasmid Asd+; pBRori β-lactamase signal sequence-based periplasmic secretion plasmid20
    pYA36340.7-kb DNA encoding the α-helical region of PspA from amino acid 3 to amino acid 257 in pYA34934
    pYA4088852-bp DNA encoding the α-helical region of PspA from amino acid 3 to amino acid 285 in pYA349354