Promega minipreps crapping out

Jody K. Hirsh jkh141 at nwu.edu
Wed Jan 3 13:54:25 EST 1996


In article <crawford-0201961220260001 at powerlarry.mib.uga.edu>, 
crawford at bscr.uga.edu says...
>
>In article <2814E93001B938D9 at office.mmc.org>, varyc.mmcri at mmc.org 
wrote:
>
>> Hi all,
>> Has anybody noticed a recent tendency for the Promega minipreps to 
fail
>when doing large numbers of (bluescript) preps?
>> I originally thought it might have been due to evaporation of the EtOH
>from the wash solution but we've seen the problem with a new kit.
>> Previously we've had no problems.
>> 
>> Any thoughts greatly appreciated.
>> 
>> Cal Vary
>
>
>Our lab has had problems with these preps as well.  We traced our 
problem
>to the host strain.  Ecoli strains which are endoA (JM 83, BL-21 etc)
>positive yielded miserable results in our hands.  We have solved the
>problem and now get excellent results.  If you would like further
>information plz feel free to e-mail me and I will explain

-- 
DH5(alpha) and XL1-bluse are recommended by Qiagen for this reason. 
Also they have less carbohydrate I think.  I would recommend switching to 
the Qiaprep Spin Plasmid kit, they come out to about $1 per prep. 

Promega kits also work much better with vaccuum than with spinning. If 
you don't want to buy their "pig" you can rig up a sidearm flask with a luer 
connector stuck in the top.  But this isn't efficient though if you have more 
than a few. 

One other thought-- is someone new doing the preps and are they possibly 
vortexing  the lysates?


Jody K. Hirsh
Northwestern University, Chicago, IL.   USA
jkh141 at nwu.edu




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