DEPC-Treating buffers etc.......

[Paul_Hand_at_HRIW05 at HRI.BBSRC.AC.UK]

     > Ken Howe wrote:
     
     > Dear Netters,
     > What's the concensus on DEPC-treating buffers (PIPES, HEPES, Tris, 
     etc) > or salt solutions (NaCl, MgSO4, MgCl2, Mn++, Zn++ etc) vs 
     filter 
     > sterilization vs autoclaving for removal of RNases?  Can I treat 
     > previously made solutions, or do I need to make them in DEPC-treated 
     > water over again?
     
     > Eric Anderson replied - 
     
     > one thing to keep in mind is that you can't treat any buffer with a 
     > free amino group (i.e. Tris) with DEPC...best thing that you can do 
     > is sterile filter or autoclave and hope for the best.
     
     
     It's also not a good idea to autoclave buffers like Tris: we prepare 
     stocks of DEPC-treated water and use them to make up Tris and other 
     solutions for RNA work. Part of the treatment is an autoclaving step 
     anyway. If you're really paranoid you can filter sterilise the final 
     solutions, but we normally don't and have had no problems so far. I 
     suspect that RNases would pass through a 0.2 micron filter anyway, but 
     it would keep the bugs out.
     
     An important point about DEPC treatment of water is to stir thoroughly 
     after autoclaving to drive off residual ethanol. We normally stir 
     vigorously for at least 2 hours on a magnetic stirrer.
     
     Paul Hand                         Horticulture Research International
     Handp at bbsrc.ac.uk