Problem with DNA extraction from plants - CTAB solution and nanodrop results (Jun/22/2006 )
It may be very trivial, but it's my first experience with DNA extraction. I'm using Steenkamp solution (a kind of CTAB) and when I add the solution to the ground leaf sample, it makes a ball and doesn't dissolve (like glue). I replaced the solution with usual CTAB solutions which appear on internet protocols. for the new one I got these figures from nanodrop. 260/280= 2.04, 260/230=2.78. for the second one I don't know if it's valid and should I work on all the samples. this figure seems too high (compared to 1.8 which mostly referred to).
The higher OD indicates RNA contamination of your DNA. If you have not treated with RNase you will have a extracted total Nucleic acid.
Thank you Ian
I used RNase A (from bovine pancreas), I put it in TE and added to all samples, I don't know why 260/230 is high for two of the samples (I didn't autocalve the CTAB solution for those that have high ratio). I was using freeze dried leaves and I didn't put the ground samples in liquid nitrogen.
What should be the reason for high OD?
thank you again.
I'm not certain of this, but I believe that adding RNAse will degrade the RNA into nucleotides, but not remove them. Since the OD depends on the nucleotide concentration, this probably will have little or no effect on the spectrum. If you precipitate after RNAse treatment, the small RNA fragments will not precipitate. Try a phenol/chloroform extraction followed by an ethanol precipitation.