BME103:T130 Group 13
(→Research and Development)
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Revision as of 23:57, 1 November 2012
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Lab Write-Up 1
Lab Write-Up 2
Lab Write-Up 3
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LAB 1 WRITE-UP
When we unplugged the PCB Board of the LCD from the Open PCR Circuit Board, the machine's LCD screen turned off.
When we unplugged the white wire that connects the Open PCR Circuit Board to the 16 Tube PCR Block, the machine could not register or measure the temperature.
On October 18, 2012, our group first tested the Open PCR Machine. At first the machine seemed overwhelming in its design. However, after following the instructions and advice from peers and professors, we were able to determine how to properly setup, program, and run a simple test.
Polymerase Chain Reaction
Polymerase Chain Reaction is a technology that amplifies a single piece of DNA. This technology works very similarly to the natural DNA replication cycle. One PCR cycle consists of three basic steps, denaturation, annealing and extension. In the denaturation step, heat (usually about 95 degrees Celsius) is used to separate the DNA into two strands. Then in the annealing step, the temperature is decreased to 50 degrees Celsius and the DNA primer, specific to the target sequence for that organism, anneal to the separated strand of DNA. The primers mark the beginning and the end of the targeted DNA sequence. Finally, the extension step required the temperature to be raised to 72 degrees Celsius so that the DNA polymerase is activated. The DNA polymerase begins synthesis at the DNA primer. This results in two double stranded target DNA sequences. The PCR cycle is repeated many times to amplify the targeted strand.
There are typically many cycles that need to take place in the PCR in order to amplify a patient's DNA.
|Template DNA (20ng)||0.2 μL|
|10 μM forward primer||1.0 μL|
|10 μL reverse primer||1.0 μL|
|GoTaq master mix||50.0 μL|
|Total Volume||100.0 μL|
We ran a total of 8 samples. We made 3 samples from Patient 1 (ID#65685) was female and aged 58. We made 3 samples from Patient 2 (ID#58278) who was also female and aged 53. The remaining 2 samples were the positive and negative controls. The positive control for this experiment was the cancer DNA template and the negative control was the no DNA template.
DNA Measurement Equipment Tester
1) Turn on the excitation light using the switch for the blue LED.
2) Place your smart phone on the cradle
Research and Development
Specific Cancer Marker Detection - The Underlying Technology
The reason that the cancer-associated sequence of r17879961 will produce a DNA signal while the non-cancer DNA sequence of the same SNP (single nucleotide polymorphism) will not produce a DNA signal lies in the arrangement of nucleotides at the molecular level. The lack of a DNA signal is due to the inability of the reverse primer to bind to the forward strand during the annealing phase of PCR. To detect the cancer-associated sequence of r17879961, the reverse primer AAC TCT TAC ACT CGA TAC AT is used. This is because the cancer-associated mutation is represented by a single nucleotide in a particular triplet: instead of the normal ATT, the middle T mutates into a C, thus rendering a triplet of ACT (which you can see in the reverse primer shown above). At the protein level, this mutation of 1 nucleotide changes the coded protein from isoleucine to threonine. As a result, the primer will not attach to the normal r17879961 DNA sequence as it will not have the corresponding base pairs (TGA) in the particular section of DNA that the mutated sequence would have.
(BONUS points: Use a program like Powerpoint, Word, Illustrator, Microsoft Paint, etc. to illustrate how primers bind to the cancer DNA template, and how Taq polymerases amplify the DNA. Screen-captures from the OpenPCR tutorial might be useful. Be sure to credit the source if you borrow images.)
(Your group will add the results of your Fluorimeter measurements from Week 4 here)