title: Deletion of yncD gene in Salmonella enterica ssp. enterica serovar Typhi leads to attenuation in mouse model.
abstract: TonB-dependent transporters (TBDTs) are bacterial outer membrane proteins that are usually involved in the uptake of certain key nutrients, 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.
authors.affiliation: Department of Microbiology, Third Military Medical University, Chongqing, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Xiong
authors.forename: Zhijin
authors.initials: Z
authors.lastname: Chen
authors.forename: Guiming
authors.initials: G
authors.lastname: Xiang
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Xiancai
authors.initials: X
authors.lastname: Rao
authors.forename: Fuquan
authors.initials: F
authors.lastname: Hu
authors.forename: Yanguang
authors.initials: Y
authors.lastname: Cong
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D050296:Microbial Viability; D012485:Salmonella typhi / Q000235:genetics* / Q000472:pathogenicity*; D014435:Typhoid Fever / Q000382:microbiology* / Q000473:pathology*; D014436:Typhoid-Paratyphoid Vaccines / Q000008:administration & dosage / Q000276:immunology; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics* / Q000378:metabolism*
chemical_list: D026901:Membrane Transport Proteins; D014436:Typhoid-Paratyphoid Vaccines; D014613:Vaccines, Attenuated; D037521:Virulence Factors