I have heard that plasmids can be stored in isopropanol for years because they remain very stable in it. Any suggestions?
I agree with Jonas and se no reason to store plasmid DNA in isopropanol. I usually store plasmid DNA both @ -20°C (in elution buffer) and in bacteria as -80°C stock.
Probably for many years. The preparation of digested plasmid I use to control for ligation efficiency (parallel +/- T4 DNA ligase reactions) has been stored in water at -20*C since 1998, and still performs consistently. Some days ago I happened to check a plasmid stored in TE at -20*C since 1990. The supercoiled form was gone, but it did transform with no problems.
I would expect 100% isopropanol to work even better.
Isopropanol is used to precipitate the DNA/ Plasmid not to store. Plasmids are insoluble in isopropanol, therefore they clings together and get precipitated. For storage purpose it is suggested to uses TE buffer or D/W
Why not store plasmid DNA dried down on a piece of filter paper @ room temperature? Then you do not have to add isopropanol now and then, nor do you have to worry about defrosting your freezer. If we are talking about long time storage.
Plasmid DNA can be stored long term in water or TE buffer (10 mM Tris, 1 mM EDTA, pH 8.0) with few negative consequences. Alcohols, including isopropanol and ethanol, are typically used at around 70% v/v to precipitate DNA, in conjunction with salt (NaCl, ~200 mM final) and/or a carrier, such as glycogen. If a long-term precipitation is to be performed, ethanol is preferred, as stability in isopropanol is not as good. It's easy to switch from isopropanol to ethanol, simply pellet and resuspend in 70% ethanol.
Years, even decades.
In my experience at least 5 years if not more.
I have experience to store plasmid long time in TE buffer. Store of plasmid on filer paper is also good method, but storage at 4oC will give better storage condition rather than at room temperature. Storage of plasmid under ppt. condition will not be a good procedure.
I have never used Isopropanol for storage but have stored precipitates with Ethanol/NaCl for 20 years and they still transform when resuspended. Similarly I store them in TE and again still intact after 20years for this long we store at -80 but that may not be nescessary.
- Badges
- Science topic