X-GAL CLEAVAGE BY V. CHOLERAE

[coyne at uctvax.uct.ac.za]

Dear Netters,

I am attempting to isolate transposon generated lacZ operon fusions in 
Vibrio cholerae by cleavage of X-gal to generate blue colonies.  According to
Bergeys, V. cholerae is lactose negative.  However, I have found that
V. cholerae is able to cleave X-gal to generate blue colour which is a major 
problem with respect to my strategy.  I would greatly appreciate it if anyone 
could supply me with an answer to the following question:

   Does V. choerae possesses a beta-galactosidase enzyme?
   (The bacterium was scored as lac- as a function of growth on lactose).

You may post the answer e-mail it directly to me.

Many thanks in advance,

Vernon Coyne
vernon at micro.uct.ac.za