Humic acids and DNA purification

Paul A. Vescio vescip at rpi.edu
Fri Sep 9 04:17:47 EST 1994


In Article <34n4i3$a26 at mserv1.dl.ac.uk>, <Herveg at bian.ucl.ac.be> wrote:
>Miguel Villegas <hcampos at usb.ve>
>
>>Some of these waters
>>have high
>>contents of dissolved humic acids (H.A.), polimers of highly
>>refractary organic 
>>material.
>
>Humic acids! I learn the existence of these compounds from Hagelberg E.:
>Humic acids contaminate some archaeological bones ... , they are extracted
>together with the DNA! So when regions of mtDNA are submitted to PCR
>amplification for haplotype determination, they inhibit the DNA Pol!
>
>How can we purify this DNA to avoid this kind of contamination, easy to
>recognize because the DNA solution is colored in brown!
>The purification technology requires some knowledge about those compounds,
>What are they, what property can be used to separate them from DNA?
Try adding Polyvinylpolypyrrolidone to your lysed cell/soil mixture.  The
PVPP absorbs quit a few of the humics.  also try an ammonium acetate/CTAB
precipitation to get rid of them.   Give me an email buzz and maybe I can
give a few more suggestions.  I have been working on DNA extractions from
sediments for about 2.5 years with some pretty good results.
--------------------------------------------------------------------------------
Paul A. Vescio                      
Biology Dept.
Rensselaer Polytechnic Institute

!!New York Rangers  Stanley Cup Champions 1994!! 



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