UNITED STATES DEPARTMENT OF AGRICULTURE
AGRICULTURAL RESEARCH ADMINISTRATION
BUREAU OF AGRICULTURAL AND INDUSTRIAL. CHEMISTRY

Beltsville, Maryland

Room 305-A
North Building

April 21, 1960

Dr. Joshua Lederberg

Assistant Professor of Genetics
The University of Wisconsin
College of Agriculture
Madison, Wisconsin

Dear Dr. Lederberg:

Thank you for your comments on our paper entitled: "The utiliza-
tion of some organic compounds by one strain each of S. anatum,

s- oranienburg, and S. pullorum," J. Bact. 59(3):361-366, March
950.

The organism requiring thiamine should have been 8. —<-
but in the process of preparation for publication, it was
accidentally transposed as S. pullorum.

I quite agree with your comments regarding the importance of
distinguishing between the availability of a carbon compound
as an energy source in a synthetic medium on the basis of its
metabolic utilizability and the specific growth requirements
of an organism. Metzger's results with pantothenate and
Pseudomonas sp. (J. Bact. 64:135, 1947) appear to show that
distinction. Further work along such lines would indeed be
desirable if we are to obtain a clear picture of the role of
various substances in the nutrition of microorganisms.

Supplemental studies on the specific growth factors required by
our 5. pullorum strain are contemplated, if we are to continue
along theee lines.

Sincerely yours,

Frank Davis, Bacteriologist
Microbiology Research Division