Research Bacteriology
Bldg. 54 = Room 16

VETERANS ADMINISTRATION

HOSPITAL
HINES, ILLINOIS

 

March 25, 1952

YOUR FILE REFERENCE:

IN REPLY REFER TO:

Dr. Joshua Lederberg
Department of Genetics
College of Agriculture
University of Wisconsin
Madison 6, Wisconsin

Dear Dr. Lederberg:

Unfortunately, in the course of a series of changes in
my own fortunes since publishing the article about which you wrote
me, I have lost both small colony variant and parent strains of
BE. coli which I used for the work I reported on in 1946, using
e-methyl 1, 4 naphthoquinone.

However, through the courtesy of Dr. W. Kirchheimer of
the Northwestern University Medical School, I have been able to
obtain a subculture of one of the strains which I used. It was
called E. celi II in my paper, a saccharose fermenter. I am for-
warding this culture to you under separate cover. He regretted
not being able to locate the E. coli I strain which I had also
originally obtained from that collection.

As I remember it, I subjected this strain to 6 serial
streakings on plain agar, picking a single colony each time, and
the culture which grew from the sixth colony was the one I used
with the quinone.

I trust that this one strain will prove satisfactory for
your purposes and that you will have no difficulty obtaining the
dwarf colonies. I shall be interested to hear what success you
have had and what conclusions you make as to whether they are in-
duced or selected by the quinone.

Very sincerely,

Ww, “8 ( o Kee \. Se, to

CHARLOTTE A. COLWELL, Ph. D.

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