Open AccessIdentification and analysis of bacterial virulence genesin vivo
Author(s) -
Kate E. Unsworth,
David W. Holden
Publication year - 2000
Publication title -
philosophical transactions - royal society. biological sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.753
H-Index - 272
eISSN - 1471-2970
pISSN - 0962-8436
DOI - 10.1098/rstb.2000.0602
Subject(s) - virulence , salmonella , biology , gene , mutagenesis , plasmid , secretion , in vivo , function (biology) , phenotype , genetics , pathogenicity island , microbiology and biotechnology , vacuole , in vitro , mutation , bacteria , biochemistry , cytoplasm
Signature-tagged mutagenesis is a mutation-based screening method for the identification of virulence genes of microbial pathogens. Genes isolated by this approach fall into three classes: those with known biochemical function, those of suspected function and some whose functions cannot be predicted from database searches. A variety of in vitro and in vivo methods are available to elucidate the function of genes of the second and third classes. We describe the use of some of these approaches to study the function of the Salmonella pathogenicity island 2 type III secretion system of Salmonella typhimurium. This virulence determinant is required for intracellular survival. Secretion by this system is induced by an acidic pH, and its function may be to alter trafficking of the Salmonella-containing vacuole. Use of a temperature-sensitive non-replicating plasmid and competitive index tests with other genes show that in vivo phenotypes do not always correspond to those predicted from in vitro studies.