Store DNA concentrated or dilute?
Stephen R. Lasky
Stephen_Lasky at brown.edu
Tue Mar 12 08:20:12 EST 1996
In article <Do4L55.HtG at ncifcrf.gov>, pnh at cockleberry.ncifcrf.gov (Paul N
> Bernard Murray (bernard at elsie.nci.nih.gov) wrote:
> : A long time transfecter in our lab maintains that storing plasmids
> : at too high a concentration (eg. much more than 1 g/l) leads to
> : concatamer formation which reduces transfection efficiency.
> How do concatamers form in purified cccDNA???? I can see how a batch of
> restriction digested vector DNA which is frozen and thawed can give you
> transformants with concatamers, but with cccDNA it doesn't make sense.
Exactly, and in addition, 1 migrogram per microliter is not really a
concentrated solution of DNA. I have been storing plasmids frozen at 2 to
5 ug/ul for years and never had any problems with restriction digests,
isolating inserts, or transfecting the plasmids into bugs or eukaryotic
cells. I haven't tried to sequence DNA that has been stored for a long
time like this, but I suspect that it would sequence.
Stephen R. Lasky Ph.D. Brown U/Roger Williams Medical Center, Providence, RI.
Phone: 401-456-5672 Fax: 401-456-6569 e:mail: Stephen_Lasky at brown.edu
America may be unique in being a country which has leapt from barbarism to decadence without touching civilization. John O'Hara.
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