Timothy Loeb
Rockefeller Institute
for Medical Research
New York,. New York
August 22,. 1958

Dr. Joshua Lederberg

Department of Genetics

University of Wisconsin
Madison, Wisconsin

Dear Dr. Lederbergs

To avoid duplication in an area which is under active
investigation by your group, the following letter is sent
to you (' on the advisement of Dr. Maurice Fox ) explaining
the lines along which I may eventually be able to develop
my doctorate thesis. In continuance of the excellent work
which you have published, . various protoplasting techniques will
be used in an attempt to determine if any differences can

be distinquished in the cell wall of E. coli K-12 as a function

"1 “qa

of the bacterium's mating type (/ FY and FT ).. If sexual differ-
entiation can be perceived at the cell wall, this distinction
will be further investigated by the use of such surface phenomena
as phage adsorption, and by immmological and chemical procedures,
If sexual differentiation appears to be solely a property of
the cytoplasmic membrane ( as your data tends to indicate ),
attention will then be turned to the kinetics of pt transfer
using radioactive sulfer as a cytoplasmic tracer,

IT would be most grateful for any advice you could give,
and specifically I have the following questions and requests:
1) Have you as yet investigated the temperature coefficient
of F transfer? 2) I understand that one of your students has

completed a thesis on a study of rf transfer. Is it possible

 
ele.

to obtain a microfilm or other copy of this thesis? 3) TI have
acquired the following coli strains from the Cold Spring Harbor
collections: 58-161 and WI 1773 CS67 and W 1; CB8100 and CS1OL.
Do you have any strains which you feel would be more suitable
for the project outlined above and if so is it possible to
procure them from you?

I'thank you for your kind attention and hope to meet you

again whenever you have occasion to be at The Institute’.

Yours truly;