Other PCRBased Assays

The PCR single-strand conformation polymorphism (PCR-SSCP) technique was also tested for the identification of Listeria genus and individual Listeria species. This approach employs the PCR amplification of a variable region of the 16S rRNA, and the analysis of the denatured amplified product by electrophoresis in a nondenaturating polyacrylamide gel. The method was found to be able to identify almost all species of the Listeria genus.[11,12] A variation of this method was also used by Manzano et al.,[13] who analyzed a short amplified fragment of the 16S rRNA gene by PCR temperature gradient gel electrophoresis (PCR-TGGE) in a polyacrylamide gel. By the use of PCR-TGGE, the species L. monocytogenes, Listeria seeligeri, and Listeria ivanovii were distinguished, whereas the L. innocua and Listeria welshimeri PCR products migrated to the same position in the gel. More recently, an identification approach based on the PCR of a fragment of the iap gene and on the analysis of the PCR product obtained by DGGE (PCR-DGGE) was also developed for the direct identification of Listeria spp. in food samples. Species-specific DGGE migration that allows the identification of individual Listeria species was obtained. Nevertheless, it should be noted that the specificity of the PCR-TGGE and PCR-DGGE methods was not tested toward Listeria grayi.[14] Other PCR-based identification approaches, such as repetitive sequence base PCR (rep-PCR) with primer sets targeting the enterobacterial repetitive intergenic consensus sequence (ERIC), 16S-amplified rDNA-RFLP analysis (ARDA), randomly amplified polymorphic DNA (RAPD) technique, and rDNA spacer PCR analysis, have also been described.[1U5-18]

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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