UNIVERSITY OF ILLINOIS

DEPARTMENT OF BACTERIOLOGY

362 NOYES LABORATORY OF CHEMISTRY
URBANA

November 5, 1951

Dr. J. L. Lederberg
Department of Genetics
University of Wisconsin
Madison 6, Wisconsin

Dear Josh:

Since Roger has come I have been continuously impressed
with the high rate of respiration in some of his pseudomonad
strains. For this reason I think we had best prepare a mutant
for our Pyruvate Oxidation Factor as an aid in the study of
our keto acid systems. Roger says that you have prepared some
mutants of his A 3.12 strain and would be likely to have one
which we could use in working out the conditions for the use
of your penicillin technique. If you have such a mutant,
would you send us a transfer and give us some notion of the
penicillin concentration you used with this organism and the
UV killing curve. We can get the latter quickly with Lu's
UV lamp but would appreciate the others if you have them
handy.

Thanks for your help.

With best regards.

Sincerglf yours,

reaper“
_ I. C. Gunsalus we

Tec/pke