RESEARCH BACTERIOLOGY-BLDG.54
VETERANS ADMINISTRATION

HOSPITAL
HINES, ILLINOIS

July 16, 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:

' Your request that I repeat my experiments
in obtaining small colony variants with 2-methyl 1,4—naphtho-
cuinone has not gone unheeded, as you may well think at this
point. It happened to arrive at an unusually busy period and
I have not been able until recently to set up the test.

Unfortunately, the only sample of quinone
available at the present time has deteriobated considerably.
The original experiments were made with a very pure product
synthesized in the chemical laboratories of the company in
which I was working.

In the one test I have managed to do,

. small colony variants have appeared in considerable numbers
in subcultures of one dilution of quinone, but not in pure
culture as I had originally obtained them. Moreover, brief
trials at subculture have indicated that they lack the sta-
bility of the original sfrains I had obtained; that is, they
revert more quickly, or else subcultures are mixed colonies
of the small colony forms and reverts, I suspect that the
impurity of the quinone may be responsible.

I am not giving up yet-I am still testing
various picked colonies for stability and will be able soon
to repeat the whole experiment. I should like very much to
be able to send you a stable culture of dwarf colonies.

Sincerely,
de, (fam 2 20

Charlotte A. Colwell

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