The efficiency of tranformation depends on the ligation mix so you may wish to plate 100-200 ul or several plates of 200 ul for each ligation. This amount is usually sufficient to obtain the isolated colony. Flame the spreader between plates and cool before each use. C. This can be reused if necessary for up to one week. Day 2 Examine the plates and determine the efficiency of transformation.
Bacteria carrying recombinant plasmids therefore form white colonies.
X-gal is very expensive but the cost can be minimized by spreading concentrated solution of the sugar on the surface of the plate rather than incorporating it in the media. Spread the solutions over the entire surface of the plate using a glass spreader. Incubate the plate at 37 degrees C until all the fluid has been absorbed. Because of the low volatility of dimethylformamide this can take up to 4 hours. Inoculate the plate with the transformed bacteria as before and incubate inverted at 37 degrees C for 16 hours.