Technical Aspects

Using an RNA template, NASBA and TMA amplify RNA via the simultaneous action of three enzymatic activities: an RNA polymerase activity, a reverse transcriptase (RT) activity, and RNase H activity. The synthesis of cDNA is primed by specifically designed primers, one end of which is a target-specific sequence, while the other end contains a promoter for the RNA polymerase. The RT synthesizes an RNA-DNA hybrid, the RNase H digests the RNA component, and the RT synthesizes double-stranded DNA; finally, the RNA polymerase produces numerous RNA copies (Fig. 1). An excellent overview of the NASBA amplification principle and primer and probe design rules is given by Deiman et al.[1]

NASBA and TMA were originally applied for specific RNA amplification, but the protocol is adaptable for DNA amplification as well, by changing template denaturation, primer design, and sample extraction.

Because the amplification product is single-stranded RNA, it can easily be detected by hybridization with sequence-specific probes. Different techniques can be used: enzyme-linked gel assay,[2] electrochemilumines-cence (ECL),[3] and real -time detection by molecular beacons.[4-7]

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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