disappearing DNA - (Sep/11/2004 )

Has anyone ever had trouble with DNA disappearing or degrading when cut with restriction enzyme? We resuspend the DNA in TE and have used several enzymes each separately with separate buffers. We cut the DNA at 37celsius and store the DNA in the fridge.
The above question relates to my other post on plasmid DNA. (see DNA plasmid extraction trouble) The few times we get what could possibly be plasmid, it does the disappearing act. We have so far assumed it is not plasmid and the problem is in our isolation method, but I wonder if something could be happaning to the plasmid after we isolate it.

PS. Why doesn't my keyboard have a degrees symbol?

on a pc the one just below the "esc" should be it :

shift+^ = °



mike

What kind of cells do you use? e.g. the strain.

Some of the cells I used to work with, this kind of disappearing-DNA problem often occured. Sometimes you just can't avoid it. Try keep the DNA all the time on ice when you are using it. And when you are not using it, keep it at -20°C