DNA assay

Blasiak J, Kowalik J. 1998. Interaction between organophosphoms compounds and DNA assayed by the restriction endonuclease EcoRI. Acta Univ Lodz Folia Biochim Biophys 13 31-67. 

HBV DNA was measured by hybridization or branched chain DNA assays (lower detection limit 20,000-200,000 lU/mL) and PCR assays (lower detection limit approximately 50 lU/mL). For references see text... 

Kern, D., et al. (1996). An enhanced-sensitivity branched-DNA assay for quantification of human immunodeficiency vims type 1 RNA in plasma. J. Clin. Microbiol. 34,3196-3202. 

Xu H, Wu HP, Huang F, Song SP, Li WX, Cao Y, Fan CH (2005) Magnetically assisted DNA assays high selectivity using conjugated polymers for amplified fluorescent transduction. Nucleic Acids Res 33 e83... 

MacPherson,J.M., Eckstein, P.E., Scoles, G.J. and Gajadar, A.A. (1993) Variability of the random amplified polymorphic DNA assay among thermal cyclers, and effects of primer and DNA concentration. Molecular and Cellular Probes 7, 293-299. 

Wang YS, Liu B (2007) Silica nanoparticle assisted DNA assays for optical signal amplification of conjugated polymer based fluorescent sensors. Chem Commun 34 3553-3555... 

An elegant approach is to capture the target DNA or RNA with specific oligonucleotides on to a microwell plate. Synthetic branched DNA bearing multiple alkaline phosphatase-labeled probes hybridizes to the target. A chemiluminescent substrate is added to produce signal. This branched DNA assay has been used in infectious disease detection (W3). 

Moreover, the unique adsorption properties of GEC allowed the very sensitive electrochemical detection of DNA based on its intrinsic oxidation signal that was shown to be strongly dependent of the multi-site attachment of DNA and the proximity of G residues to GEC [100]. The thick layer of DNA adsorbed on GEC was more accessible for hybridization than those in nylon membranes obtained with genosensors based on nylon/GEC with a changeable membrane [99,101,102]. Allhough GEC has a rough surface, it is impermeable, while nylon is more porous and permeable. DNA assays made on an impermeable support are less complex from a theoretical standpoint [7] the kinetics of the interactions are not compUcated by the diffusion of solvent and solutes into and out of pores or by multiple interactions that can occur once the DNA has entered a pore. This explained the lower hybridization time, the low nonspecific adsorplion and the low quantity of DNA adsorbed onto GEC compared to nylon membranes. 

DNA assays will certainly play an essential role in future medical research, along with proteomics. This makes high-throughput screening methods necessary. Parallel DNA separation chips coupled with high-sen-sitivity detection such as LIF or mass spectrometry (56) should be able to provide the required structural information in less time than with techniques currently employed (12). 

Labarca, C. and Paigen, K. (1980). A simple, rapid, and sensitive DNA assay procedure. Analytical Biochemistry, 102 344-352. 

The inhibition of RNA synthesis may be followed by the use of [3H]-deoxyuridine or [3H]-uridine in much the same manner as those used for the DNA assays above [183-186]. 

C. Labarca and K. Paigen, Anal. Biocbem. 102, 344-352 (1980). A Simple, Rapid, and Sensitive DNA Assay Procedure. ... 

Fig. 3. Mukiparameter light scatter and DNA assay. Burkitt lymphoma cells induced into apoptosis by irradiation with 4 Gy were analyzed for forward light scatter (FSC) and propidium iodide fluorescence (FL2). Region , viable cells Region 2, apoptotic cells.

The main limitation of the subdiploid DNA peak assay is that it cannot be used accurately on a cycling population, since the fluorescence from apoptotic S and G2M cells overlays the fluorescence from viable G cells. However, this limitation can be largely overcome by the use of the multiparameter light scatter and DNA assay. 

As mentioned above, thick- and thin-film electrodes have been used for different DNA assays, either as genosensors or detectors. Here the discussion will be focused on genosensor devices based on hybridisation event that is, the electrode is used as support/detector of the hybridisation event. 

DNA assays 0X174 HaeIII, Salmonella PCR Glass DC amperometry... 

Figure 12 Examples of immunoassay systems and DNA assays performed with magnetic bead technology (a) sandwich assay (b) competitive assay (c) bridge assay to determine proteins (d) DNA and RNA assays.

In cases A, B and C, the DNA base or sugar modifications can be introduced via automated solid-phase synthetic methods using suitable DNA building blocks. As an alternative route, DNA modifications can be introduced by solid-phase methods which are applied during or after the complete automated solid-phase synthesis, as is the case for the preparation of the DNA assays B and D. 

Organic and inorganic intercalators not covalently attached to oligonucleotides were first reported for study of CT in DNA. These experiments provide little information, because of the lack of an accurate measurement of the distance between the D and A and the concern for pairing of the intercalators. A significant experimental improvement came with DNA assays bearing covalently linked intercalators. By use of these systems systematic measurement of distance dependence and base sequence dependence was possible. These experiments led to three important observations ... 

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