low plasmid yields in dh5alpha

Murata Takehide via methods%40net.bio.net (by take_murata from hotmail.com)
Fri Feb 22 07:59:41 EST 2008


Dear Ed, 
Reduce the cultivation period.  During long period, E. coli may lose plasmid but get anti-antibiotics secreted in media and E. coli can be alive. 
 
Take
http://www.brc.riken.jp/lab/dna/
 
> Hi.  We've been going through our old plasmids and makingfresh stocks.  We've found a few that we're not able tominiprep and get reasonable concentrations (<50ng/ul).We're using Qiagen miniprep kits and invitrogen dh5alphaand have had much success purifying>One thought was that the plasmids might be producing aproduct that is toxic to dh5alpha, and maybe they'd dobetter in another strain. Has anyone had a similar problemthat was resolved by growing the plasmid in another strain?>I'm thinking XL1-blue might help because it retains thelac repressor, and that might help stop any backgroundexpression from the lac promoter.  Any other ideas wouldbe appreciated.  Thanks>-Ed
 
_________________________________________________________________
確定申告大丈夫?Live Searchで検索していろいろ下準備。
http://search.live.com/results.aspx?mkt=ja-jp&q=%E7%A2%BA%E5%AE%9A%E7%94%B3%E5%91%8A&FORM=MGCEAB


More information about the Methods mailing list