title: Changes of physiological and biochemical properties of Salmonella enterica serovar Typhimurium by deletion of cpxR and lon genes using allelic exchange method.
abstract: To construct a novel Salmonella attenuated live vaccine, the cpxR and lon genes were deleted from a wild-type Salmonella enterica serovar Typhimurium (S. Typhimurium) using allelic exchange method, resulting in S. Typhimurium CK31 (DeltacpxR), CK38 (Deltalon), and CK111 (DeltacpxR/lon). These mutated strains were grown normally, as was the wild-type strain. The biochemical properties of the mutants remained highly similar to those of the wild-type. In comparison with the wild-type, 1.5 to 3.3-fold increases of fimbrial products such as Agf, Fim, and Pef fimbria in the mutants CK31, CK38, and CK111 were observed by using a transmission electron microscope and dot blotting. Furthermore, CK38 and CK111 morphologically appeared elongated in shape and produced 2.0- and 3.2-fold increases, respectively, of capsular polysaccharide, which is a major antigenic component. Approximately 10(4)-fold attenuation assessed by analysis of LD(50) of BALB/c mouse was observed by deleting the lon/cpxR (CK111) genes. This result indicated that deletion of lon and cpxR genes induced significant attenuation.
authors.affiliation: Division of Biological Sciences, Pusan National University, Busan 609-735, South Korea.
authors.forename: Sam Woong
authors.initials: SW
authors.lastname: Kim
authors.forename: Ki Hwan
authors.initials: KH
authors.lastname: Moon
authors.forename: Hyung Suk
authors.initials: HS
authors.lastname: Baik
authors.forename: Ho Young
authors.initials: HY
authors.lastname: Kang
authors.forename: Sung Koo
authors.initials: SK
authors.lastname: Kim
authors.forename: Jeong Dong
authors.initials: JD
authors.lastname: Bahk
authors.forename: Jin
authors.initials: J
authors.lastname: Hur
authors.forename: John Hwa
authors.initials: JH
authors.lastname: Lee
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D003001:Cloning, Molecular; D055786:Gene Knockout Techniques / Q000379:methods*; D005798:Genes, Bacterial / Q000235:genetics; D007928:Lethal Dose 50; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D010641:Phenotype; D049070:Protease La / Q000235:genetics*; D015203:Reproducibility of Results; D022562:Salmonella Vaccines / Q000235:genetics / Q000633:toxicity; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D014613:Vaccines, Attenuated / Q000235:genetics / Q000633:toxicity
chemical_list: D001426:Bacterial Proteins; D022562:Salmonella Vaccines; D014613:Vaccines, Attenuated; C085504:CpxR protein, Bacteria; D049070:Protease La