Blue color comes late lately in yeast 2 hybrid

Riekeltje Koedood rkoedood at
Thu Jul 11 12:11:28 EST 1996

Forgot to mention, I modified the original protocol by adding 2mM MgCl2
(based on previous experiments with lac Z, tissue culture and embryos).
This significantly increased the blue color. The original protocol didn't
have any Mg in it.

Marieke Koedood
Boston University

Edward K.L. Chan (echan at wrote:
: We are having problems to reproduce the blue color in our positive
: controls.  Sometimes it takes 2-3 hours for the blue color to
: show up.  The problem is that at other times the color is so weak that
: it may take overnight to come up.  Any helpful comment welcome.
: We are using the HybridZap system from Stratagene and the tech support
: has not been very helpful for this problem.  The yeast colonies are
: transferred to Whatman paper and processed for color development.
: A discussion on the importance of each reagent/step may be most useful.
: Thank you in advance.

: Ed Chan

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