FEDERAL SECURITY AGENCY
PUBLIC HEALTH SERVICE
WASHINGTON 25, D.C.

 

SN REPLYING, ADDRESS THE
PUBLIC HEALTH SERVICE

REFER To:
Toc. Research Laboratory,
411 East 69th St., New York 21, N. ¥.

April. 10, 1950,

Dr. Joshua Lederberg,
Department of Genetics,

The University of “isconsin,
College of *griculture,
Medison 6, Wisconsin.

Dear Joshua?

Thanks for the strains, reprints, and information. I will
be glad to test the prolineless mutant on our sample of hydroxy-
proline. Copies of our joint reprint, together with a few copies of
the “xnerientia paper, are being sent to you under separate cover.

I had not been intending to publish the note which appeared
in MGB, out will be glad to consider that you have sufficiently
twisted my arm so that I am obligated to overcome my hesitation about
flocding the market with short notes, I will try some time soon to
write it up in slightly greater detail. I will be glad to omit the
menticn of lambda at vour request but it does seem appropriate to
mention the formal possibility, quite without this evidence, of a
particle intermediate in size between a molecule and a cell. If you
don't mind I would like to send this manuscript to you for comment
before submitting it for. publication.

Miss Cahn and I aporeciate your offer to try to fit her in
if a vacancy arises. I imagine you will. hear from her as soon as the
necessary documents are available. ileanwhile, the situation has shifted
in thet the veteran who threatened to displace her has been assigned
elsewhere. We are therefore planning to keep her on for another year.
Iam sufficiently convinced, however, that she would be better off as
a graduate student so that I would be glad to let her leave in the
early fall if an opening should arise, even though we might have to
scramble around a bit for a replacement.

Our EMB has been behaving satisfactorily. Thanks for the
note on suggesting a source for a pood product. Our fermentation
experiments, originally designed to test the imortance of segregation
in connection with our studies on the phenomic lag, have led into some
unexpected channels. Certain of your strains have proved to be completely
unable to utilize the sugars for which they are fermentation negative,
as they don't show traces cf growth on these sugars as a carbon source.
Dr. Joshua Lederberg April 10, 1950,

In other instances, however, the negative fermentation,as shown by
absence of staining on EMB medium,is nevertheless accompanied by an
ability to produce perfectly heavy, rapid growth on the same sugars.
This has been observed with W-677 which grows well on galactose and
arabinose, though we have confirmed your description of this mutant

as being fermentation negative on these sugars. On matritol it dees

not grow but it dees give rise to reversions which then grow well on
mannitol but without staining on EMB mannitol, I woncer if this is

the sort of behavior that is referred to by Esther as a slow fermenter?

With best regards,

Sincerely,
é

(levzcee

Bernard D. Davis

BDD/h1

P.S. - Just got a letter from Guthrie telling me that he is looking
for a laboratory job, but giving no reason for his resignation.