To the best of our

knowledge, this is the first m-PCR method published to detect Salmonella, Campylobacter, and E. coli O157:H7 simultaneously from watershed samples. The m-PCR assay allowed less time and reagents to be used. Because quantification with plating was not possible with these watershed samples, the qRT-PCR method reported here allows pathogens to be quantified rapidly and accurately. Inhibitors present in both water and soils selleck products are present in watershed run-off and our method was optimized so that the assay was just as sensitive as the use of pure cultures in PBS. This research was funded by a USDA National Research Initiative (NRI) grant #6226-63000-001-16 awarded to P.M., A.M.D., D.J.D., S.C.R., and Andrew Sharpley. “
“Site-directed integration/mutagenesis systems are used to carry out targeted transpositions on DNA. The well-characterized IS30-element and its transposase have numerous advantages that predestine it to be a good candidate for such applications. In order to generate nonflagellated mutants of Salmonella Enteritidis, a new site-directed mutagenesis system has been developed and applied. The system was constructed based on the assumption that the DNA-binding FljA component of the fusion transposase would bind to its target (the

operator of fliC), and as a consequence, insertions could be concentrated in the flagellin operon. The system consists of two components: one expresses the fusion transposase and the other is an integration donor plasmid harbouring the (IS30)2 reactive structure. click here The application of this site-directed mutagenesis system on a strain of S. Enteritidis 11 (SE11) resulted

in several nonmotile mutants with fliD insertion that could next serve as negatively markered vaccine candidates. Analysis of less motile mutants generated by the fusion transposase revealed further hot spot sequences preferred by the fusion construct. Insertional transposon mutagenesis is a frequently used technique with the enormous advantage not only of the generation of new phenotypes, but the identification of the mutated gene directly. Transposon mutagenesis can be achieved by several means including both random and site-directed methods. Site-directed or targeted mutagenesis mediated by insertion sequence (IS) elements and transposons relates to the use of a novel recombinant DNA technology for the targeted modification of DNA. Because of their ability to generate insertions, IS elements and transposons represent a useful and efficient tool in biotechnology by introducing ‘foreign’ DNA into the genome of various plants, animals or bacteria (for a review, see Coates et al., 2005; Kolb et al., 2005; Voigt et al., 2008). There are two major ways of modifying the mobile element enable it able to carry out targeted transposition. One can alter the characteristics of the transposition itself by modifying the specificity of the transposase and/or its target sites.