XGAL & IPTG -- how low can you go?

[Glen Shearer]

We're spending tons of dollars on XGAL and IPTG for blue/white selections.

Now we use per 100 ml LB agar : 80 ul XGAL (50 mg/ml stock in DMSO) and
400 ul IPTG (24 mg/ml stock).
I seem to remember seeing a post that lower amounts will work well for
blue/white plates.

Anyone tried lower amounts with good results?

thanks,
Glen
gshearer at whale.st.usm.edu