Dyes for PCR

Michael Coady coady at ERE.UMontreal.CA
Tue Mar 8 16:09:29 EST 1994

In article <763154840snz at genesys.demon.co.uk> Duncan at genesys.demon.co.uk writes:
>Thanks for all the responses but could someone actually list the dyes. The UK
>is very backwood when it comes to Biotechniques. I don't know of any 
>academic libraries in the locality that get it. Over here it isn't free and 
>is rarely seen. Although I have a personal subscription it only started from 
>Vol. 14. I can get the journal but it means a trip to the Science Reference 
>library in London and that will waste a whole day commuting etc.

	Well sure.. though I wouldn't mind going to London to get
some article photocopied :-).
	They found that either xylene cyanol or bromophenol blue
would inhibit PCR.  Tartrazine (FD& C Yellow #5, Aldrich Chemicals)
inhibited the PCR at 1500 mg/ml.  Yellow food colouring from the
supermarket (Schilling brand, McCormick & Co., Baltimore) is
also PCR-compatible up to a dilution of 1:160.  Cresol red didn't
have enough solubility to be inhibitory. Ficoll seemed to be inhibitory
but sucrose was not.  Inhibition was also found with visible conc's
of metacresol purple, thymol blue, methylene blue, caramel
colouring and red, green and blue food colourings.  Neutral red
and basic fuchsin was colourless at the pH of the reaction.
The authors recommend using 2 ul of 60% sucrose/1 mM cresol red
in a 10 ul reaction and they colour templates by adding 1-2
ul of Schilling yellow food colour per 100 ul of diluted DNA.
	The authors also mention other advantages of these dyes
such as not causing a shadow when doing EtBr staining of agarose
gels.  For those who've joined this discussion lately, le me
stress that this is from Hoppe et al, in Biotechniques Vol. 12,
p. 679 (approximately) and I am not affiliated with that 
group at all.


Michael J. Coady
The opinions expressed above are solely those of the author and do not,
in any way, shape or form, represent the Universite de Montreal.

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