Dh5 alpha cultures not viable ?

Duncan Clark blackhole at abuse.plus.com
Fri Feb 24 12:15:52 EST 2006


Historians believe that in newspost 
<mailman.1224.1140796133.29584.methods at net.bio.net> on Fri, 24 Feb 2006, 
Siddhartha Parida <sidharth4 at gmail.com> penned the following literary 
masterpiece:
>I had ordered a culture of DH5alpha from a supplier and when i
>inoculated it in a LA + Amp (10mg/ml) the culture was able to grow,

DH5alpha should not be able to grow on its own without an Amp resistant 
plasmid, on Amp plates. It is Amp sensitive.

>i
>streaked it into slants and keep it at 4C for a month but now when i
>want to work on it again, the culture is not growing , i have repeated
>ot many times but without sucess.

I store all strains stocks at -70C in 2 volumes LB plus 1 volume 50% 
(v/v) glycerol. My >25year old stocks are fine. -20C as glycerol stocks 
or 7% DMSO stocks IMHO is better than storage at 4C. I'm sure I still 
have some 10year old room temp stocks as stabs in 0.7% agar LB in screw 
caps eppendorfs which were wax oversealed and they are still viable. For 
real safety, lyophilise.

Duncan
-- 
I love deadlines. I especially like the whooshing noise they make as
they go flying by.

Duncan Clark
GeneSys Ltd.


More information about the Methods mailing list