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dna extraction from soil samples - (May/11/2010 )

Hello all!

I am new in this forum. Sending sunny greetings from Germany... :P

I started to work in terrestrial ecology field few weeks ago. My project is to asses microbial diversity in polluted soil using qpcr. But I already faced first problem, which is DNA extraction. I tried with protocol they usually use in the lab for "normal" soil. The concentrations were very law, the most problematic is 260/230 ratio (around 0,7 -1,4). I also tried with NucleoSpin Soil Kit, results pretty the same...

I need ideas, advices... how to isolate relatively pure DNA with reasonable concentrations from soil, enivronmental samples

Thank you in advance.

-alkb-

have you tried a pcr with your DNA and checked the yields/quality of the result?

Maybe the bad reading comes from something in the polluted soil interfering with the photometric reads. I have the experience that with soil these photometric and quantifications methods are only partly reliable.....too many factors that can influence your results...

-gebirgsziege-

gebirgsziege on May 11 2010, 11:02 AM said:

have you tried a pcr with your DNA and checked the yields/quality of the result?

Maybe the bad reading comes from something in the polluted soil interfering with the photometric reads. I have the experience that with soil these photometric and quantifications methods are only partly reliable.....too many factors that can influence your results...


Thanks for your answer. No, I didnít run pcr yet, because I though good dank quality is a "must be"!!! :P

-alkb-

It is good if you have, but I had horrible samples which were working perfectly, so I would give it a try.

-gebirgsziege-

I think humic acids have the same absorbance as DNA, so your concentrations might be totally wrong.
You can always add a cleanup step if you want with a Qiaquick or MinElute.
Try the PCR and don't forget the BSA.

-Maddie-