Development and Properties of Subsp. 15 NIIEG Vaccine Strain without the Gene.

The genomic analysis of all subspecies , as found in Gen Bank NCBI, reveals the presence of genes encoding proteins like to the multifunctional RecBCD enzyme complex in and other bacteria. To date, the role of the gene in , which encodes the alpha chain of exonuclease V, in DNA metabolism processes, has not been studied either in vitro or in vivo. subsp.

Superoxide dismutase B gene (sodB)-deficient mutants of Francisella tularensis demonstrate hypersensitivity to oxidative stress and attenuated virulence.

A Francisella tularensis live vaccine strain mutant (sodB(Ft)) with reduced Fe-superoxide dismutase gene expression was generated and found to exhibit decreased sodB activity and increased sensitivity to redox cycling compounds compared to wild-type bacteria. The sodB(Ft) mutant also was significantly attenuated for virulence in mice. Thus, this study has identified sodB as an important F.

A method for allelic replacement in Francisella tularensis.

A vector for mutagenesis of Francisella tularensis was constructed based on the pUC19 plasmid. By inserting the sacB gene of Bacillus subtilis, oriT of plasmid RP4, and a chloramphenicol resistance gene of Shigella flexneri, a vector, pPV, was obtained that allowed specific mutagenesis. A protocol was developed that allowed introduction of the vector into the live vaccine strain, LVS, of F.