Polymerase chain reaction figure

FIGURE 28.14 The polymerase chain reaction (PCR). Three cycles are shown the target region appears after the third cycle. Additional cycles lead to amplification of the target region. 

FIGURE 13.21 Polymerase chain reaction (PCR). Oligonucleotides complementary to a given DNA sequence prime the synthesis of only that sequence. Heat-stable Taq DNA polymerase survives many cycles of heating. Theoretically, the amount of the specific primed sequence is doubled in each cycle. 

Figure 28.9 The polymerase chain reaction. Details are explained in the text.

Figure 40-7. The polymerase chain reaction is used to amplify specific gene sequences. Double-stranded DNA is heated to separate it into individual strands. These bind two distinct primers that are directed at specific sequences on opposite strands and that define the segment to be amplified. DNA polymerase extends the primers in each direction and synthesizes two strands complementary to the original two. This cycle is repeated several times, giving an amplified product of defined length and sequence. Note that the two primers are present in excess.

A variation on the theme of conventional assay uses both lanthanide-labeled and biotin-labeled single strands to form split probes for sequence of target strands (Figure 12).120 When both of these bind to DNA, the complex binds (via the biotin residue) to a surface functionalized with streptavidin, immobilizing the europium and allowing assay to be carried out. This approach is already very sensitive to DNA sequence, since both sequences must match to permit immobilization of the lanthanide, but can be made even more sensitive by using PCR (the polymerase chain reaction) to enhance the concentration of DNA strands. In this way, initial concentrations corresponding to as few as four million molecules can be detected. This compares very favorably with radioimmunoassay detection limits. 

Figure 13.16 The polymerase chain reaction for the amplification of DNA sequences. DNA is heated to separate the two strands. A primer is attached to the 5 end of each strand and extended using DNA polymerase 1. The two new strands are separated as before and the cycle repeated up to 30 times.

Figure 2 Cytokine gene expression in immunopotentiating reconstituted influenza virosomes (IRIV) stimulated peripheral blood mononuclear cells (PBMC). PBMC were cultured in the presence or absence of IRIV. On days 1 and 2, culture cells were harvested and total cellular RNA was extracted and reverse transcribed. The cDNAs thus obtained were tested in real time polymerase chain reaction assays in the presence of primers specific for the indicated cytokine genes. Source From Refs. 6 and 9.

Regarding reverse transcriptase polymerase chain reaction (RT-PCR) analysis to assess a splice site variant, as seen in Fig. 12.6, if one designs forward (F-) and reverse (R-) RT-PCR primers to span the SNP (which in turn creates or abolishes a splice site), one wiU have different size PCR products (labeled a, b, and c in the figure) that can easily be resolved on a gel. 

Figure 3.25 Polymerase chain reaction. The steps involved in the chain reaction are as follows (i) Incubation of the DNA at a temperature above 90 °C in order to separate the two strands of the DNA duplex, (ii) Cooling of the solution to about 50 °C to allow annealing of the primers to the template (i.e. the nucleotides bind to the template DNA according to the basepairing rules), (iii) Finally, addition of the polymerase and Mg ions to extend the nucleotide primer and complete the synthesis of the complementary DNA, which takes place at about 70 °C. (iv) The sequence (i) to (iii) is repeated to allow another extension to occur many repetitions can be carried out which results in enormous multiplication of the DNA strands. NTPs - deoxyri-bonucleoside triphosphates.

Figure 1.3 Polymerase chain reaction, or PCR, allows scientists to produce many exact copies of a piece of DNA. The process is illustrated here.

FIGURE 3.10 Polymerase chain reaction can amplify a single molecule of DNA into millions of identical copies. 

Are there any other possible uses for the construction of complex topological species One possible application is in the mass production of DNA polyhedral catenanes by biological means, such as the polymerase chain reaction (PCR) (Saiki et al. 1986) or by production in vivo. Figure 21 illustrates that semi-conservative replication (the mechanism used by DNA polymerases) cannot reproduce a stable branch. The DNA with different sequences in the two arms of the branch (cartooned as dashed and solid lines) leads to two heterologous duplex DNA molecules, rather than a second branched molecule. 

Sources of DNA DNA may be obtained from white blood cells, amniotic fluid, or chorionic villi (Figure 32.15). For amniotic fluid, in the past, it was necessary to culture the cells in order to have suffi cient DNA for analysis. This took two to three weeks to grow a suffi cient number of cells. The development of the polymerase chain reaction (PCR, see below) has dramatically shortened the time needed for a DNA analysis. 

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