Polymerase Chain Reaction (PCR)
Definition
Polymerase chain reaction (PCR) using a method used to amplify a small amount of DNA in order to allow scientist to study it in detail[1]. RNA can also be extracted from samples and converted into complimentary DNA (cDNA) for PCR amplification [4]. Primers are used to identify the location of the DNA in the sample. Enzymes that have defined segments of DNA are taken advantage of to recreate cDNA [4].
Primers
PCR primers are single strands of DNA used to identify the location of the DNA in the sample. This refers to a small set of nucleotides in DNA. For bacteria and archaebacteria primers that are ubiquitous to the 16s ribosomal RNA (rRNA) are used [1,2,3,5,6]
Method
There are three essential steps when conducting PCR.
1. The melting of the target DNA [2]
2. After the DNA has been melted the primers are combined into a synthesized DNA [2]
3. Finally, there is a primer extension by thermostable DNA polymerase [2]
Uses
PCR is helpful for scientist as it recreates small strands of DNA using either DNA or RNA. This is especially helpful in looking at genetic ecology studies as it allows scientists to get a closer look at DNA [5]. Pathogens among samples are able to be seen using PCR [1,4,6]. Bacterial cultures is the traditional way to sample these, but it usually only accounts for a small amount of microbial biomass [1].
References
1. Bruce, K.D., Hiorns, W.D., Hobman, J.L., Osborn, A.M., Strike, P., Ritchie, D.A., 1992. Amplification of DNA from native populations of soil bacteria by using the polymerase chain reaction. Applied and Environmental Microbiology 58, 3413–3416. https://doi.org/10.1128/AEM.58.10.3413-3416.1992
2. Henson, J.M., French, R.C., n.d. THE POLYMERASE CHAIN REACTION AND PLANT DISEASE DIAGNOSIS 30.
3. Picard, C., Ponsonnet, C., Paget, E., Nesme, X., Simonet, P., 1992. Detection and enumeration of bacteria in soil by direct DNA extraction and polymerase chain reaction. Applied and Environmental Microbiology 58, 2717–2722. https://doi.org/10.1128/AEM.58.9.2717-2722.1992
4. Schochetman, G., Ou, C.-Y., 2021. Polymerase Chain Reaction 5
5. Tsai, Y.L., Olson, B.H., 1992. Detection of low numbers of bacterial cells in soils and sediments by polymerase chain reaction. Applied and Environmental Microbiology 58, 754–757. https://doi.org/10.1128/AEM.58.2.754-757.1992
6. WILSONl, K.H., Blitchington, R.B., Greene, R.C., 1990. Amplification of Bacterial 16S Ribosomal DNA with Polymerase Chain Reaction. J. CLIN. MICROBIOL. 28, 5.