Thursday, February 19, 2015

2 19 2015 Test DNA Extraction Methods

Due to the low yields of high molecular weight DNA in the 96 Well Plate extraction and some advice from Brent and Steven, I'm now directly comparing DNEasy extractions with DNAzol. I selected 4 samples from the Oyster Bay September 2014 samples (1N9-12 18,19,20,21) to extract. I put equal amounts (visually pieces about the size of a grain of rice made of mantle and ctenidia) of each sample into two separate 1.5 ml tubes. One set of tubes is being processed using the DNEasy single sample kit with reagents from the 96 Well plate kit since both use the same reagents and the 96 Well plate kit is far fresher. The other set of tubes has been processed using the standard DNAzol technique.

The DNEasy kit takes an overnight incubation at 56 C so I filled the tubes with 180 ul ATL buffer and 20 ul Proteinase K. Vortexed to mix, centrifuged for 30 seconds, vortexed to resuspend and stuck into the incubator. These tissues will be processed tomorrow.

The DNAzol kit protocol went as follows.

  1. Added 1 ml DNAzol to tissue tube. 
  2. Homogenized using cleaned/previously used pestle with 5-10 strokes and grinding.
  3. Incubated at room temp for 10 minutes. 
  4. Centrifuged at 10,000 g for 10 minutes. 
  5. Moved 700-900 ul supernatant to fresh tube.
  6. Added 500 ul 100% EtOH (bottled opened 1/20/2015)
  7. Mixed through inversion. 
  8. Incubated for 3 minutes at room temp. 
  9. Centrifuged at 5000 g for 5 minutes
  10. Removed supernant
  11. Washed with 1 ml 75% EtOH
  12. Vortexed until pellet broke up. 
  13. Centrifuged at 2000 g for 2 minutes. 
  14. Removed supernatant.
  15. Washed with 1 ml 75% EtOH
  16. Vortexed until pellet broke up. 
  17. Centrifuged at 2000 g for 3 minutes.
  18. Carefully removed all supernatant. Used 1 ml pipetter to remove bulk and 200 ul pipetter to remove leftovers. 
  19. Added 300 ul Nanopure water.
  20. Mixed through pipetting. 
Lots of DNA created. DNA elution is almost milky in two of the samples. 

Will quantify tomorrow after I finish DNEasy extraction. 

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