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SCHOOL OF MEDICINE

SAINT LOUIS

THE EDWARD MALLINCKRODT
DEPARTMENT OF PHARMACOLOGY
EUCLID AVENUE AND KINGSHIGHWAY

March 15, 1958

Dr. Joshua Lederberg
Department of Genetics
University of Wisconsin
Madison, Wisconsin

Dear Josh:

We have had some very interesting results from E. coli strains
which you sent us. We have made penicillin protoplasts with
each of the five strains. None of them accumulates nuceotides.
However, they all leak ultraviolet absorbing material into

the medium so that at the present time the interpretation of
the results is very difficult. I wonder if the function of
sucrose and magnesium in protoplast formation isn*t partly to
prevent the leakage of materials at too rapid a rate. This
leakage in E.coli under the influence of penicillin had been
previously obersved by Bink] yy» who identified the ultraviolet
absorbing material as uracil.v I want to try other stabilizing
substances on these protoplasts since it may be possible to
prevent this leakage.

Somewhat more interesting is the nucleotide accumulation in
the DAP protoplasts. With one strain we observed nothing, but
in the other strain, there seemed to be a,small accumulation
of nucleotide. This would correspond to the accumulation of _
nucleotides in staphylococci in lysine-deficient medium which

I mentioned to you. We isolated a compound from a small scale
run with DAP protoplasts and in general it has chromatographic
and electrophoretic properties similar to the staphylococcal
compound. To go any further, we have to have a very much larger
quantity of material which we are in the process of trying to
get_ now. It would be very worthwhile for us to have additional
DAP strains, particularly the organism used by Bauman and
Davis, and by Meadow and Work, and I would very much appreciate
it if you could send additional strains to me as soon as con-
venient for you. It may be that one of them will accumulate

a larger quantity of nucleotides.

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¢ 98

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Dr. Joshua Lederberg

March 15, 1958

Page 2

We have rather large scale preparations of extracts from
various types of coli protoplasts from the above experiments,
and if any of these would be interesting to you, I would be
very glad to send them.

Best regards,

Sincerely,

seal Strominger

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