help X-gal

Stephen Mamber mamber at
Thu Jul 6 16:08:48 EST 1995

In article <3t1gs8$6rb at>, Trevor Charles <charles at> says:
>rgoto at (ronald goto) wrote:
>> our stock solution of X-gal is 100 ug/ml 
>>in DMF and we dilute as we need it,  well a new student dituled it in water, I 
>>can not see any ppt but it did freeze solid at -20 C (clue for me it wasn't in 
>>DMF) question is? is it any good??? 
>Could it be that the student made up the stock solution in DMSO? We routinely make our X-gal stocks in DMSO, rather than DMF. DMSO is, of course, solid at
There were two recent articles in Biotechniques (sorry, issues not handy)
about using X-gal in a mixture of water and DMSO.  Rationale was substitute
for 'hazardous' DMF.  Looked reasonable to me, but I recall putting X-gal
in 100% DMSO once and over several days, a faint blue color appeared (even
though the solution was frozen in the refrigerator.  Still, you may be able
to salvage your solution via the Biotechniques procedures.  SWM

mamber at

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