Cloning bacteria: no growth
 

Hi

I am cloning competent E coli (tranformed with DNA ligated plasmid) on agar plate with ampicilin (50ug/mg) + X-gal/IPTG. There's no growth (blue/white) on my plate. Even when i use control plasmid with and without insert, there is no growth! What could be the problem?

Re: Cloning bacteria: no growth
 

1. It could be the competent cells have been thawed. Buy a new batch and test the control plasmid with them.

2. Your LB plates might contain too much antibiotic. Are you sure you added the right amount?

3. Find someone in your lab or building who has cloned successfully, then watch every step of what they do. If they use different volumes of cells to ligation, or a different waterbath, or different tubes (sometimes microfuge tubes can bind DNA), copy what they did and try again.

Good luck!