The results showed that compared with LM EGD-e, LM-Δrli87 grew faster (P < 0.05) at low temperature (30 °C), high selleck compound temperature (42 °C), and in alkaline condition (pH = 9), similarly (P > 0.05) in acidic and high osmatic pressure (10% NaCl) conditions. When cultured in medium containing 3.8% ethanol, the growth was not significantly different between the two strains (P > 0.05). When cultured at pH 9, they had similar growth rates in the first 5 h (P > 0.05), but the rates were significantly different after 6 h (P < 0.05). The
expression of rsbV, rsbW, hpt, clpP, and ctsR was upregulated in LM-∆rli87 compared with LM EGD-e at pH 9, indicating that the rli87 gene regulated the expression of the five genes in alkaline environment. Our results suggest that the rli87 gene has an important regulatory role in LM’s response to temperature (30 and 42 °C), alkaline
“TonB-dependent transporters (TBDTs) are bacterial outer membrane proteins that are usually involved in the uptake of certain key nutrients, NU7441 datasheet for example iron. In the genome of Salmonella enterica ssp. enterica serovar Typhi, the yncD gene encodes a putative TBDT and was identified recently as an in vivo-induced antigen. In the present study, a yncD-deleted mutant was constructed to evaluate the role of the yncD gene in virulence. Our results showed that the mutant is attenuated in a mouse model by intraperitoneal injection and its virulence is restored by the transformation of a complement plasmid. The competition experiments showed that the survival ability of the yncD-deleted mutant decreases significantly in vivo. To evaluate its vaccine potential, the yncD-deleted mutant was inoculated intranasally in the
mouse model. The findings demonstrated a significant immunoprotection against the lethal wild-type challenge. The regulation analysis showed that yncD gene promoter is upregulated under acidic condition. The present study demonstrates that the yncD gene plays an important role in bacterial survival inside the host and is suitable for the construction of attenuated vaccine strains as a candidate target gene. TonB-dependent transporters (TBDTs) are transporter proteins located in the Thiamine-diphosphate kinase outer membrane of Gram-negative bacteria. They are dependent for their function on contact with the TonB complex, which transduces the proton motive force of the cytoplasmic membrane to energize substrate transport through specific TBDTs across the outer membrane (Schauer et al., 2008). The TonB system, including the TonB complex and TBDTs for key nutrients such as iron and nickel, is of great medical relevance because the survival of pathogenic bacteria in their hosts depends on their capability to take up these nutrients (Perkins-Balding et al., 2004; Miethke & Marahiel, 2007; Schauer et al., 2007, 2008). In the genome of Salmonella enterica ssp. enterica serovar Typhi Ty2 (S.