[DIYbio] Re: Bacterocins as an alternative selection method

Ideally you would have an E Coli strain that carries all the Kan-synthesis genes  - but the first one! - in the chromosome.

You would then transform it with a plasmid carrying the missing Kan-synthesis gene (e.g. KanA or KanB) and a Kanamycin immunity gene. It would then start producing kanamycin and be immune against it.

So it kills all the other bacteria that haven't taken up the plasmid. The plasmid itslef would aso be selfish, because if the plasmid is lost, it loses Kanamycin immunity and gets killed.


Plasmid size would not be much bigger than usual plasmids. Usually you have (100 bp promoter? +) 900 bp kanamycin resistance, now you have 1000 bp kanamycin synthesis and 1000 bp immunity. Both expressed from the same promoter, saving bp.