THE UNIVERSITY OF CHICAGO

CHICAGO 37+ILLINOIS

DEPARTMENT OF BOTANY

26 May 195),

Dear Dr. Lederberg,

If you recall, we met while you were at the
University of California, Dept. of Bacteriology, one summer
session teaching a course in Microbial Genetics. I am now
here at the University of Chicago teaching Microbial Genetics
among other courses in Cytology and Genetics and continuing
my research in microbial genetics,

I am currently doing some work which re-

quires auxotrophs of E. coli. It is in this comection that I
am writing. Such a request may involve as many as 25-30 mutants
Since I would want auxotrophs with single, specific requirements
covering the amino-acids, vitamins, growth factors, purines, and
pyrimidines. They should be as stable as possible, i.e., very
low spontaneous reversion rate. Your help will be most appre~
ciated since it would involve considerable effort on my part to
assemble such a complete collection.

Sincerely,

a) adaan

E. D. Garber