We have good luck with applying the IPTG & X-Gal to the surface only
of the plates. As always TIME=$. I mix small amounts of my two
stocks and spread 100ul of this stock on the plates circa half an hour
before I plate my cells (spread or streak). The stocks we use:
2% X-Gal (in pmsf)
The final is equivalent to 83 ul 2% X-Gal, 17 ul 100 mM IPTG/plate.
I have not tried to see how much less I could use, but believe that it
could be lowered some.
Ann L. Williams
Oklahoma State University
Biochemistry & Molecular Biology
246 Noble Research Center
Stillwater OK 74078-3035
Phone: (405) 744-9340
Fax: (405) 744-7799
e-mail: awilliams at biochem.okstate.edu