X-gal and IPTG, when will it be added to the culture base?

Dear brothers

for your question:( Supplemental time: 2009-11-13 21:29)

Answer 1: At the end of the day, X-gal is only the substrate of semi-lactose glycosidease, the amount of the substrate does not have a definite value, as long as the concentration of the substrate is sufficient color, generally in the culture base, the final concentration of X-gal is 40ug/40ug/ug ml, the final concentration of IPTG is 24ug/ml, you can show color, we put these directly on the surface, it is easier to show color, and then a little waste

Answer 2: If you use a lot, very anxious to use, do a good job directly added to the medium. But if you only need one or two plates, now time to add, and x-gal is very expensive, I am generally painted, each plate x-gal 40ul (20mg/ml), IPTG 4ul (200mg/ml).

answer 3: Usually a well-matched amp^- LB plate, x-gal 40ul (20mg/ml), IPTG 4ul (200mg/ml) added to the liquid, and then mixed the coating plate. It can also be applied to the plate first.

answer 4: Mix in the bacteria after 1 hour of shaking bacteria. X-GAL is afraid of light and is careful to avoid large amounts of light. The lights can be turned off when operating on the ultra-clean table. The blue-and-white spot screening bacteria I do are too dense and generally not fully coated. Take one-tenth, and 40XGAL and 4IPTG mix on the line. If the coating is less, the blue spots will not be obvious. Found that blue spots can not obviously put the plate 4 degrees and a half hours later the color will be a little deeper

a answer 5: in the prefabribrio containing appropriate antibiotics 90mmagar Add 40ul2% x-gal (20mg/ml), 7ul20% IPTG (0.8mol/L) on the plate, when applying the action to be fast, and even.