No Blue Colonies...I'm not that good.
jsupolek at aol.com
Tue Feb 19 01:09:05 EST 2002
I'm trying to shotgun clone in chromosomal fragments of a cellulolytic anaerobe
into pUC19. Everthing has gone well, and I'm using a Rec- strain of E. coli
for transformation. But all I get are white colonies. NO blue colonies at all,
not even on the control bacteria with unligated plasmid. Some plates had
X-gal, and some had Bluo-gal. Some had IPTG and some did not. Amp
concentration was 10mg/ml, and I did 1:1, 1:10, 1:100, and even 1:1000
dilutions. Colonies were in numbers in proportion to the dilutions, so they
were my E. coli. Why didn't any of them turn blue?? I don't necessarily need
the b/w colony selection for what I'm screening for, but it would be helpful.
I would appreciate any help. Thank you, S. Polek
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