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SST tubes, a cheap alternative

mwgaunt at molbiol.ox.ac.uk mwgaunt at molbiol.ox.ac.uk
Tue Aug 10 11:50:48 EST 1993

  In article <@CGNET.COM:genpt at strix.udac.uu.se>, 5 Aug 1993, (which
  unforunately was not recieved on the local net) Peter Thoren writes:

   >  .....Thomas et al describe a simple way to separate organic and
   >  water phase when extracting DNA. They use so called gel barrier
   >  tubes (SST tubes, Becton Dickinson......
   >  Does anyone out there have a FAX number or address to this company
   >  or are there other places with similar products.

   Similar products are very close at hand. Mukhopadhyay and Roth (Nucleic
   Acids Res. , Vol 21, no. 3, p781 ) report the use of autoclaved DOW
   Corning Corp vacuum grease as a gel barrier for phenol/chloroform
   extraction. Although this sounds bizarre the principle is the same;
   an inert gel, silica, has a density lower than that of water but higher
   than both phenol and chloroform, so on centrifugation the gel settles
   between the aqueous and organic phase creating a gelatinous barrier.
   Thus recovery of the aqueous phase is higher than normal and free from
   any potential protein contamination from the organic interphase.

   Whilst this source of silica gel would seem prone to contamination from
   impurities in the vacuum grease, I have previously used DOW's high vacuum
   grease for the extraction of high copy number viral RNA. I used only 
   freshly opened grease which was autoclaved, aliquoted then spun.
   In work where shorter microfugation times are sufficient high vacuum grease
   is less suitable as it requires over 5 mins at 12-13k for an adequate 
   barrier to form. A lower density grease may work here.

   The company 5'-> 3 Prime ( address by Graham Atherton, 5 Aug 1993) 
   catagorises its gel barriers, which it terms phase lock gels, as heavy 
   and light depending on the density. The two catagories are used for 
   different manipulations, for instance high is always used on RNA 
   extractions ( psst company seems eager to give free samples). 
                                        Hope this helps

                                           Mike Gaunt (mwgaunt at ac.ox.uk.)
                                           Inst. Virology
                                           Oxford  UK.

p.s. I am trying to recall the name of a Finnish University which begins 
     with M....  .I'll recognise the name when I hear it, so I would be 
     very grateful for any suggestions ( with a pronunciation guide please).

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