Preparation of Competent E. coli Cells

Select plates; 100µg/ml ampicillen in cooled LB agar, pour plate (25ml to 90mm petri dish) and when set spread a mixture of 50µl 20mg/ml X-gal in DMSO and 50µl 1M IPTG in water (filter sterilised).


pBluescript plasmids are not very good at going blue; incubation at 4°C for an hour followed by a couple of hours back at 37°C sometimes inproves colour. If things still really arenít turning blue then incubation at 42°C can help.