Unrversity oF MINNESOTA

Tue Mepicat ScHoot
Mrinneapoiis 14

DEPARTMENT OF BACTERIOLOGY

i . August 30, 1957
AND IMMUNOLOGY $
wectd Sipe 4,

Joshua and Esther Lederberg
Department of Bacteriology
University of Melbourne
Carleton N3

Melbourne, Victoria, Australia.

Dear Josh and Esther:

We were quite pleased that you got off on your trip without undue delay.

Trust that you have found the trip both pleasant and profitable. Your climate
could be no more unpleasant that Minnesota and Wisconsin these past few days.
It has rained. No not really rain, rather tears of the Republicans after

teh cefeat of Kohler by Proxhire.

We were in Madison yesterday. We went down to see how everything was progressing.
Most of you were on vacation or trips but we suw several old friends and had

a thoroughly enjoyable time. Visited Bob in the hosphtal. He was running around
from place to piace cheerin: up the rest of the floor. His problem worked

out very well from all indications. A considerably stronger case can be made

for cytoplasmic inheritance now. I hope taat he tries to infect now.

We have nothing really new since last December. The mut-nts which come out

of heteroka yons are frequently different one from the other---i.e. of

8 cyst- dissociates there are 3 distinctly differant types, as indicated by
ability to form prototrophic heterokaryons. We do get the feeling that there

may be recombination involved also but the mut nts complicate things. Presumptive
recoibinants are always rare-- less than 2% of the products of sectoring
prototrophs. None (presumptive recombinants) can be obtained by direct plating
of the spores from mixed growth. That we can go into at some later date p«rhaps.

Ann was busy isolating new mutants and Heumann was in the lab. Could not find
Newt Morton to learn something about the new facilities in Medical Genetics.

oar transduction experiments have been sonething less than spect:cular. Products
of the metabolism select for different types. More or less the same type of
thing that Werner Braun has with alanine and Brucella. TI must sot know how to
design experinents for I always seem to get involved in this sort of stuff.

Oh well, it keeps the boys off the streets.

We have been looking at some clinical materials. The Streptomyces are non-
pathogenic? We have found that some of the orginims called Nocardia are

S treptomyces through and through. Where the Streptomyces comes from is
in doubt.

S yve rton is still in Europe but will start back in a week. He intends to

hide away in a lab here next year and avoid al_ administrative duties. This
is unlikely however because he failed to delegate any authority.

4 3
I had best end. Oyr very best wishes. id Okey b. Keble