Plasmid Problems!!!!

Gregg Silk greggsilk at
Tue Jun 9 19:11:39 EST 1998

I routinely use 200 ug/ml AMP for high copy number plasmids like pUC, 50 ug/ml
is a disastor.

Also I understand the Qiawell 96 ULTRA is preferred, with the cells grown in LB
so that the cells do not overgrow, clogging the filters.

Clones with inserts over 8 kb won't prep well using Qiagen.

Some genomic DNA over 5 kb may be unstable even in DH5alpha, will delete down
to AmpR and ori about 1.5 kb, lack cloning or primer sites and give no signal
when sequencing.

You may have several problems going simultaneously, so keep an open mind.

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