Trivial transformation improvement

George Rutherford gruther at
Fri Feb 25 14:12:55 EST 2000

In article <0325688F.00464EDB.00 at>,
a.krimer at wrote:

> I'm sorry Rafa bit I agree with Chen. In fact,  I have performed a
recovery time
> curve several years ago.
> Depending on stress conditions my bacteria needed about 5-15 minutes to
> After 15 minutes I have got more clones each time, and after 50-60 minutes,
> every 20-25 min (doubling time) I have got approximately twice colonies each
> time.
> I think it is not so much work to do this work to optimize the recovery time.
> Hope this helps.

Snipped previous

Sigh....I guess I'll toss in my $.02. First, I have doubts about the
doubling time of the jazzed-up bacteria we use in molbio conforming to the
garden variety doubling time of 20 minutes. When I make electrocompetent
DH5alpha, the doubling time is 35-40 minutes (by OD550); XL-1 Blue are
slower yet (both grown in SOC). Note that these are untransformed cells
that lack the extra baggage of a replicating plasmid.

You may be seeing a doubling of colonies over your time course, but do you
know whether or not you are seeing a doubling of identical sibs or might
they actually be unique clones? I realize that this would be a pain to
test, but I don't think you can include or exclude either possibility
without an apprpriate experiment. Personally, I would never do such an
experiment (after all, I'm not a micro guy); I just let the little
beasties recover for 30 to 90 mins., depending on what else I'm doing.



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