Inoue Competent Cell procedure

Ned Mantei mantei at
Fri Mar 15 01:24:29 EST 1996

In article <4ia7ur$eq3 at>,
Christian.Moews at (Christian Moews) wrote:

> friedmrd at (Richard Friedman) wrote:
> >Out of curiosity, Why do we need to grow the cells at 18oC prior to making
> >them competent? Seems pretty cold to me.
> Also for E. coli membrane fluidity is critical. (Eu-) Bacteria
> maintain a constant fluidity by regulating the content of unsaturated
> fatty acids.
> If you lower temperature,  this will increase the amount of those
> fatty acids which will by disturbance through the C=C bonds facilitate
> the entry of foreign DNA.
> I did not find this written, but it sounds pretty plausible.

An interesting speculation. My theory had been that more bacteria die and
lyse during growth at 37 C compared to <30 C, and that the released DNA
would compete with the plasmid DNA you want to transfect.

Ned Mantei
Dept. of Neurobiology, Swiss Federal Institute of Technology
CH-8093 Zurich, Switzerland
mantei at   Fax: +41-1-633-1046

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