polysaccharides in DNA extractions

Jack Kramer kramer at news.miami.edu
Fri Aug 21 19:13:38 EST 1992


In article <1992Aug21.154346.18547 at ccu.umanitoba.ca> browns at ccu.umanitoba.ca (Stuart Brown) writes:
>
>I use a CTAB extraction to remove polysaccharides from plant and fungal DNA
>preps.  Add CTAB to 1% and NaCl to 0.7M, mix, then extract 2X with chloroform.
>Excellent description of this method in "Current Protocols in Molecualr Biology"(the Big Red Book).  I think removing the polysaccs. is much easier than trying
>to digest them away.
>

Thanks for all the responses.  The majority have been along these same
lines.  I have used the CTAB procedures, even increasing the CTAB to
5% and 3x the normal buffer to tissue ratio.  This helps for most
plants.  Lyophilizing the tissue and keeping it frozen under liquid
N until thawed in the hot CTAB helps even more.  However, in some
really slimey cultivars, after 2 extractions of the CTAB with
chloroform/isoamyl alcohol, the first isopropanol precipitation still
produces a majority of slime.  Some of the white DNA can be fished
out of the slime and works in subsequent PCR but most of it is
buried in the slime.

Further suggestions are solicited.



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