How to preserve bacteria at 4 degree - (Jun/24/2014 )

Dear all, 

Does anyone know is there any method can use to preserve bacteria at 4 deg. cel? tq. 

Nothing lasts forever, but a stab culture will be about as good as you will get.

Since I have no 80C I keep making stock cultures of my bugs every now and then and thats how I preserve them in the fridge.

I would like to make my cells survive for a relatively short period (weeks) between making more preps, but without loosing the plasmid (~11 kb) and without recombination of it (retroviral vector). I was storing the remains of liquid cultures in a fridge for a day or over a weekend, but this is a bit longer time. I will do a -70 stock too, for a long-term storage, but I don't want to use it after few weeks again.

I never done a stab culture before, can I just stab a normal LB agar I use (with ampicilin) or do I need a special medium for that? I suppose for a few weeks it would probably survive on the plates where they were cultivated, but at the time I picked them they were already making satellite colonies, so that woudn't be a good idea.

A stab should last at least a couple of weeks, but like any culture kept at 4, it will degrade over time, so there is no guarantee that it will work well. I would use the normal growth medium + agar for the stab.