Are you trying to digest plasmid DNA from agro to make sure you have
transformed a binary vector construct?
Yield and quality of DNA from agro are usually much lower than you
would get from E. coli, so sometimes it is difficult to directly
analyze DNA isolated from agro.
I have had good luck using Qiagen plasmid minipreps. Usually, I get
DNA of good enough yield and quality to see restriction digestion
products. In the past, using simple alkaline lysis type procedures,
results were typically more variable- sometimes I could see digestion
products, sometimes not. However, I found the DNA was always of
sufficient quality to retransform into E. coli. This means that to
analyze a plasmid from agro, you may need to transform the DNA back
into E. coli, where prepping and doing a digest will be trivial. If
results of the DNA analysis from E. coli look good, you know your
plasmid in agro was OK.
On Jun 18, 2008, at 11:02 AM, priyadarsini Tripuraneni wrote: