Hi
I am having problems with isolating plasmids from the dam negative
E.coli strain JM110. I have read that it has a endonuclease that cleaves
double stranded DNA and that this is the reason for the problems. Still
I manage to isolate some of my plasmids, but not the others. I have
tried SV Wizard miniprep (column) and ordinary isopropanol-method. After
isolation and digestion with restriction enzymes I can see no bands on
the gel.
All the plasmids are low-copy, but the ones I have trouble with have a
copy-up mutation that makes the copy number about 10 times higher than
the ones I have managed to isolate from.
Any help would be appreciated!
Trond Erik Vee Aune
