October 15, 1951.

. Dr. PB. R. Edwards,
Enteric Bacteriglogy Laboratory,
Communicable Disease Center,
Box 185, Chamblee, Ga...

Dear Dr. Edwards;

_ Firstly, Mr. Zinder and I wish to. record our thanks for the large
set of Salmonella cultures, and the gift of d-serum, which have arrived
in good condition and are being actively used.

-A preliminary survey shoxs that there 1s a very close correlation
between the presence of the XII somatic antigen and the capacity of
the celis te adeorb 2 filtrable agent with "transforming" activity
from preparations from S. typhimuriun. Further experiments are under
way to determine whether this absorgtion is actually succeeded by
serological or cultural changes between so many distinct serotypes.
The only exception to the correlation is that S. pullorum and gallinarum
may adsorb very slowly or not at all. The XIl-carrying S. coli types

should be very interesting experimental material in view of their
cultural distinctiveness.

In an sarlier letter, I mentioned sir. Zinder's experiments with
S. typhimurium. The only extension 0 inter-typs recombinations so
far has been with typhimuirum x typhi. Previously, we had been able
to secure alterations of typhi in the direction of rhamnose- or of
arabinose-fergentation. With the help of your d-serua, a possibly
more interesting experiment was carried out. In the presence of d-anti-
serua in soft agar, typhi cells,exposed to FA (filtrable agent) from
typhimirium, produced new flagellar types in 2/4 trials. The new types
resemble typhi culturally, but do not react with d-antiserum. #2 carries
the "i" antigen, presumably from typhimurium. We were unable to diagnose
#1 with the few sera at our disposal. Cultures of these types, as well as
of the "parental" bacteria are ehelosed: Typhimurium LT~2 (Phage Type 2
from Lilleangen) and Typhi sY¥9 (received from Kauffmann as the Watson
strain). We would appreciate it if you could scrutinize these cultures
more adequately with the typing sera at your disposal. The possibility
is not completely eliminated that the new types are "artificial phases"
occurring independently of treatment with PA. This seems unlikely,
but we are multiplying our controls to cover this contingency.

Yours sincerely,

Joshua Lederberg,
Associate Professor of Genetics
P.S. Theodcultures are dried on silica gel to preserve them and facdli-
tate their shipment. ‘The bacteria may be resuscitated by breaking the
tubes below the label and pouring the granules into broth, Most of

the ceils are on the granules nearer the rounded end of .thentube.

ar, Zinder worked out a very satisfactory and dimpla modification

fcr Gard's technique, based unon the growth tubes used in mycological

' work. About 3.al. of: serum ager is added te babes af sha fora illus-
trated. The ingewlun, ia then introduced at ona’ end. Phase alterations
result, in adgratioa te the other. The method iq especially weicone for

its” econoay. dn serum, —

“dele