Nucleic acids amplification techniques

Alternative methods of diagnosis include enzyme immunoassay, DNA probes, and nucleic acid amplification techniques. 

Antibody capture of viruses can be used as a preparatory step in nucleic acid amplification techniques. Immunocapture of virus particles can be used to streamline and/or optimize the concentration, purification and specificity requirements of polymerase chain reaction assays. 

Nucleic acid amplification techniques will undoubtedly have a substantial future impact on the practice of laboratory medicine. Ultimately, the spread and acceptance of these techniques will be limited by cost and other considerations. 

Birch, L., Dawson, C. E., Cornett, J. H., and Keer, J. T. (2001) A comparison of nucleic acid amplification techniques for the assessment of bacterial viability. Lett Appl Microbiol. 33,296-301... 

We have exemplified BART applications in molecular IVDs and demonstrated its compatibility with various amplification methods, its ability to detect and quantify different targets, to cope with crude sample preparations and to provide rapid results under challenging conditions. Overall, BART is a universal reporter system for any molecular in vitro diagnostic tests based on isothermal nucleic acid amplification techniques. 

Saldanha J, Gerlich W, Lelie N, Dawson P, Heerman K, Heath A. An international collaborative study to establish WHO international standard for Hepatitis B virus DNA nucleic acid amplification techniques. Vox sang 80 63-71, 2001. 

Recombinant luciferases and stable liquid ATP standards have increased the reliability of ATP biomass assays. Detection limits of ATP and ATP+AMP assays have reached the level of a single cell and can, combined with filtration techniques, reach 1 cell/mL. The assay of ATP+AMP is the most reliable method for hygiene monitoring. With immunocapture, bacteriophages or nucleic acid amplification combined with sensitive ATP reagents bacteria can be identified. In the near future we expect to see an abundance of user-friendly systems at acceptable prices. 

Walker, G. T., et al. (1992). Strand displacement amplification—an isothermal, in vitro DNA amplification technique. Nucleic Acids Res. 20, 1691-1696. 

Several of the enzymes involved in the processes of repheating, transcription and reverse transcription are available commercially and are used by molecular biologists in the manipulation of nucleic acids. One of the most important of these is Taq polymerase (Taq), which is a thermostable DNA polymerase named after the thermophihe bacterium Thermus aquaticus from which it was originally isolated. This enzyme is especially important, as it is central to the technique known as PCR, which allows sophisticated, targeted in vitro amplification and manipulation of sections of DNA or RNA. DNA... 

To properly accession and purify nucleic acids for analysis, the receiving laboratory must know the sample type. Both heparin and urine have been reported to inhibit PCR, to the detriment of blood samples containing the former and nearly all samples of the latter. In recent years, extraction technology and amplification chemistry have improved so that each sample type is susceptible to analysis. Proper identification of sample type provides the receiving laboratory with an opportunity to apply appropriate techniques to its extraction and analysis. 

SELEX is a widely used technique for screening of aptamers which are nucleic acid ligands. According to this method, a pool of DNA with a random sequence region attached to a constant chain is constituted by amplification then transcribed to RNA. RNA pool is separated according to the affinity of RNA molecules to a target protein. DNA molecules obtained by reverse transcription from retarded RNA molecules are amplified and the cycle is repeated. 

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