Wednesday, June 24, 2015

6 24 2015 qPCR Quality Check

Today I ran a qPCR quality check to determine if our Opticon two is producing valid data. I did this because the other day we noticed a discrepancy with the data that showed samples in the top and bottom rows had lower expression than those in the middle rows. To test if the machine was working properly I made a master mix including a template of isolated gDNA that I know amplifies and equally distributed it across the plate.

Primer:
1505Ol_Act_FGACCAGCCAAATCCAGACGABC6/13/2012205560O.luridaActin, adductor muscle
1504Ol_Act_RCGGTCGTACCACTGGTATCG6/13/2012206060O.luridaActin, adductor muscle 

Reagent Table:
VolumeReactions X52
Ssofast Evagreen MM 10520
FWD Primer0.526
REV Primer0.526
Nuclease Free H2O8416
gDNA152

The sample I used was from Oly seed oyster isolations I did a while back. 
Sample Info:
Sample IDDateTimeng/ul
NF205/7/201511:17 AM876.31

To make the master mix I added all the reagents together from greatest volume to least volume and then added the gDNA template. I vortexed briefly to ensure homogeneous mixture. I then pipetted 20 ul of this mixture into every other well to make a checker board pattern on the plate. 

Plate Layout:
123456789101112
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample
SampleSampleSampleSampleSampleSample

This pattern was to test the machines fluorescence reading capabilities across the entire plate without having to fill every well with sample. 

I ran the following program which is the same for all the other qPCR's that I have been running.

StepTemperatureTime
Initiation95 C10 min
Elongation95 C30 sec
60 C1 min
Read
72 C30 sec
Read
Repeat Elongation 39 times
Termination95 C1 min
55 C1 sec
Melt Curve Manual ramp 0.2C per sec Read 0.5 C55 - 95 C30 sec
21 C10 min
End

Results:
Amplification
Melt Curve
 Plate Fluorescence

As you can see from the amplification, while all of the well should have had exactly the same amplification there was a significant difference between wells with some wells being orders of magnitude higher. The melt curve shows similar. My favorite image though is the plate fluorescence which shows a rough estimate of the fluorescence detected in each well by the machine. Clearly the center wells have higher fluorescence detection than wells along the edges of the plate. At this time it is apparent that we need to recalibrate the Opticon as it clearly is not producing valid data.

1 comment:

  1. Curious to see what log scale looks like, and range of Ct values. Clearly tops out differently

    ReplyDelete