Thread: bacterial transformation

Hi,
I got into this new lab yesturday, and we were doing bacterial transformation. In order to increase bacterial competency, we snap freezed the bacteria in liquid N2.
My mentor told me that it increased the cell competency by 5 fold...
Does anyone know why?

Thanks

is it permeating the membrane?

I know that some of the things we do to increase competence, like the use of MgSO4, are done just because they work. No one really understands why exactly. I don't know if that's the case with liquid Nitrogen, you'd have to check the literature.

Increases membrane permeability is the broad answer, how we don't always know.

Increases cell survival during freeze. Nothing to do with permeability. Making cells competent is harsh and slow freezing is also harsh, and cells die.

Certainly liquid nitrogen is used for storing cells, but I don't think that's the use they are putting it to in this case though. If his supervisor said it increased competence and he was just talking about freezing for storage, he must have misspoke.

For some reason I was picturing some sort of process of repeated snap freezing followed by thawing, which can be used to lyse cells. (Although, obviously not to that extent.)

Thanks for your replies,

I also think that it was snap freezed to increase cell survival and ultimately the number of resulting competent cells.