cloning confusion - HELP!!

Carine Tischmann Carine.Tischmann at
Tue Nov 19 16:44:17 EST 1991

Thanks for taking the time to read and respond to our posting.  We are
confident about our ampicillin levels.  When plating out competent
cells on amp+ and amp- plates, we get growth on the amp- plates but no
growth on the amp+ plates as predicted.  Furthermore, we have made up
several liquid broth solutions and several different batches of plates,
all of which have produced the same results. The plates and the broth
have been made from the same initial broth solution.

In regard to the yeast contamination, we are not completely ruling that
out yet.  It is a possibility we hadn't thought of, but the colonies do
look and smell like E.coli.  We have managed to grow up unrelated, amp
resistant DNA in liquid medium as a control.

We are in the process of running another transformation right now and
will definitely keep you updated.

Once again, thank you very much.

Carine Tischmann
Carine.Tischmann at

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