During infection, SigE is not required for colonization of the respiratory tract of immunocompetent mice. However, it is needed for a specific set of functions associated with virulence, particularly those involved in surviving the innate immune response when the infection

progresses in immunocompromised mice. Although SigE systems are widely conserved, the details as to which aspects are shared and which have diverged are complex. As evidence accumulates Repotrectinib from studies in different bacteria, it is becoming apparent that these sensory modules are important for Selleckchem SB525334 stress survival, particularly with respect to the cell envelope. However, the nature of the stresses that SigE systems combat varies. During infection, comparisons are even more difficult, since differences are seen not only amongst SigE systems from one pathogen to another, but also within different niches in the host or during the progression of disease for a single pathogen. Methods Strains and media A complete list of strains used in this study

can be found in Table 1. B. bronchiseptica strains are derivatives of the previously described B. bronchiseptica strain RB50 [58]. B. bronchiseptica was maintained on Bordet-Gengou (BG) agar (Difco) containing 10% defibrinated sheep blood (Hema Resources) and 20 μg/ml streptomycin. In liquid culture, B. bronchiseptica was grown in Stainer-Scholte broth [59] with aeration. G protein-coupled receptor kinase Chloramphenicol was used at 20 μ/ml and IPTG at 1 mM

where noted. The RB50ΔsigE mutant was constructed as described below. E. coli strains used to measure SigE activity are derivatives of MG1655 that carry the σE-dependent rpoHP3::lacZ reporter (strain CP-868596 mouse SEA001 [34]). E. coli strain BL21(DE3) pLysS was used to express constructs for protein purification. E. coli were grown in LB broth in a gyratory water bath with aeration. Ampicillin was used at 100 μg/ml, tetracycline at 20 μg/ml, and kanamycin at 15 μg/ml as needed for experiments with E. coli. Table 1 Strains and plasmids   Strain name Genotype Source, Reference E. coli SEA001 MG1655 ΦλrpoHP3::lacZ ΔlacX74 [60]   SEA5036 BL21(DE3) ΔslyD::kan pLysS pPER76 [61]   XQZ001 BL21(DE3) ΔslyD::kan pLysS pXQZ001 This work   SEA4114 CAG43113 ΔrpoE::kan ΔnadB::Tn10 [62]   SEA008 SEA001 pTrc99a [62]   SEA5005 SEA001 pSEB006 This work   XQZ003 DH5α pXQZ0003 This work   SS1827 DH5α pSS1827 [63] B.