X-Gal replacement - help needed

Damian Bond damian.bond at virgin.net
Wed Aug 11 14:28:11 EST 1999

We have invented a superior form of X-Gal for use in detection of
transformed cells in agar or plaque assays.

The compound works in exactly the same way as X-Gal and can be utilised in
any assay utilising expression or interruption of the Lac Z operon.

The substrate gives a much more intense colouration than X-Gal. Independent
feedback confirms that most false positive isolates and therefore work
arising from interpretation of pale blue colonies is avoided. The
interpretation is much more clear.

The new compound is also resistant to autoclaving. In other words we can
supply LB Agar with IPTG and the new Gal already incorporated. All the user
needs to do is add water, autoclave and pour plates. No more messing around
with stock solutions in DMSO with addition to cooling agar or spreading on
dry agar plates

I am trying to assess whether there is a need for such a product and to
guess at idea of volumes. The price of such a product is directly related to
volume. The cost of synthesising a new compound is very high for small
quantities. For small quantities, my initial costings show that the product
would be approximately twice as expensive as the current X-Gal method (i.e.
$ US 24 per plate to the end user).

Is this price premium justified by the improved convenience in preparation
and ease of reading ?

Could anyone using X-Gal in LB Agar please respond to me and a) let me know
if this is of interest and b) how many plates your lab would use in a year.

If anyone is using X-Gal or similar Chromogenic substrates for other
applications, such as mammalian cell tissue culture, please contact me with
ideas of quantities used. We have synthesised similar compounds with the
same improvements in stability and clarity for Glucuronide, Glucoside and

Finally if any companies are interested in distribution of such a product -
please contact me.

Thanks in advance for your help.

Damian Bond
 e-mail damian.bond at virgin.net

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