DNAse contamination in plasmid preps

[pnh at ncifcrf.gov]

Michael Cooley (szcooley at chip.ucdavis.edu) wrote:

|: Has anyone else had a problem with degradation of plasmid preps?
|
| I had a similar problem a while back and found that the problem was with 
| the genotype of the bacteria. If the bacteria is HB101 it has the 
| wild-type endA gene. I switched to JM109 and the problem went away.

You might want to have a look at this paper which describes exactly this
problem and compares plasmids obtained from different strains of E. coli:

@article{Taylor1993,
author = "R. G. Taylor
     and D. C. Walker
     and R. R. McInnes",
title = "{{\em E. coli}} host strains significantly affect the
quality of small scale plasmid DNA preparations used for sequencing",
journal = "Nucl. Acids Res.",
volume = "21",
pages = "1677-1678",
comment = "mini-prep",
year = "1993"}

| :::::REMINDER:::::::REMINDER:::::::REMINDER:::::::REMINDER:::::::REMINDER:::: |
|                                                                               |
| The FAQ list for bionet.molbio.methds-reagnts can be retrieved by FTP or read |
| through a WWW hypertext link such as Mosaic. It is available by anonymous FTP |
| from ftp.ncifcrf.gov as the file pub/methods/FAQlist, by anonymous FTP from   |
| net.bio.net as the file pub/BIOSCI/METHDS-REAGNTS/METHODS.FAQ, by Mosaic at:  |
| http://www.ncifcrf.gov:2001/~pnh/info.html, or upon e-mail request to me:     |
|                                                                               |
| Paul N. Hengen, Ph.D.                           /--------------------------/  |
| National Cancer Institute                       |Internet: pnh at ncifcrf.gov |  |
| Laboratory of Mathematical Biology              |   Phone: (301) 846-5581  |  |
| Frederick Cancer Research and Development Center|     FAX: (301) 846-5598  |  |
| Frederick, Maryland 21702-1201 USA              /--------------------------/  |
|                                                                               |
| :::::REMINDER:::::::REMINDER:::::::REMINDER:::::::REMINDER:::::::REMINDER:::: |