Crystals during X-gal staining

Basavaraju Shankarappa bsh at MED.PITT.EDU
Thu Apr 21 16:35:28 EST 1994

> I have been using X-gal to stain cells blue after transient tranfections. 
> The cells are blue allright but there are lots of crystals in the stain so
> the results are not very photogenic.  The problem seems to arise when the
> X-gal stock (10% in DMF, frozen at -20 C) is diluted 1:100 in the working
> buffer for staining (5mM K ferricynanide, 5mM K ferrocyanide, 2 mM MgCl2,
> made up in PBS).  As soon as the X-gal hits the aqueous buffer the
> solution goes cloudy. 
> Does anyone know how to prevent this? Am I stuck with filtering? 
> Thanks.
> Allison Haggarty

	Hi Allison:
	Sometime back there was an article in BioTechniques describing
the use of DMSO as a solvent for X-gal instead of DMF.  I know that 
DMSO is much more miscible with water than DMF.  I think that might
solve your problem. 
	Raj Shankarappa
bsh at

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