Inactivation of aSerpula (Treponema) hyodysenteriaehemolysin gene by homologous recombination: Importance of this hemolysin in pathogenesis ofS. hyodysenteriaein mice

Abstract

The role of Serpula hyodysenteriae hemolysin in the pathogenesis of swine dysentery was studied. The inactivation of a gene, tly, encoding a hemolysin, and the virulence of a tly− mutant in mice is reported. We obtained chromosomal integration of the distrupted tly gene via homologous recombination in a S. hyodysenteriae wild‐type strain following electroporation. A plasmid construct, in which the tly gene was disrupted by a kanamycin‐resistance gene, was used for the electroporation. The mutants obtained had reduced hemolysis indicating that the tly encoded hemolysin is not the only hemolysin produced by S. hyodysenteriae. Mice infected with the tly− mutant had fewer cecal lesions than mice infected with the wild‐type S. hyodysenteriae. From these results it was concluded that the tly encoded hemolysin may be an important virulence factor, but not the only one. It was demonstrated that gene transfer to spirochaetes can be achieved through electroporation.

Inactivation of Serpulina hyodysenteriae flaA1 and flaB1 periplasmic flagellar genes by electroporation-mediated allelic exchange

“…To date, only the kanamycin gene has been reported to be functional as a genetic marker in S. hyodysenteriae (59). We have demonstrated that the cat marker is an alternative to kan, and the availability of two functional genetic markers in S. hyodysenteriae will be of great utility in the construction of defined mutants altered in more than one genetic locus.…”

Purification and characterization of VSH-1, a generalized transducing bacteriophage of Serpulina hyodysenteriae

“…Transferring genes into S. hyodysenteriae cells by electroporation to form stable recombinants has been accomplished (23,31). From these experimental results, 500 ng of total DNA, consisting of plasmid and construct DNA (S. hyodysenteriae gene disrupted with an antibiotic resistance gene), was electroporated into 10 10 cells to obtain five recombinants.…”

Physical and genetic map of the Serpulina hyodysenteriae B78T chromosome

“…Three S. hyodysenteriae genes conferring hemolytic activity to transformed Escherichia coli have been cloned (23,24). One of these genes was further characterized and designated tly (34). For convenience these genes will be (Fig.…”

“…Genetic exchange between S. hyodysenteriae cells has not been reported, and only recently has this bacterium been transformed (34). Therefore, classical genetic studies, which have often proved useful for studying the genetics of pathogenicity in many bacteria, have not been applied to S. hyodysenteriae.…”