July 18, 1953

Dr. T. Puck

Biophysics Laboratory

University of Colorado Medical School
Denver 7, Colorado

Dear Ted:

We are leaving in a week or so to drive to San Francisco to the S.A.5.
meetings. Our itinerary is not yet fixed, though we would probably prefer
the northern route. But can you tell us whether you expect to be at home
in August, 3c that we could welgh the chances of a detour to Denver? Within
rather wide margins, the relevant dates would be about August 1 and August 22,
Perhaps we will see you at the meeting itself.

I enjoyed your ms,, but as I feared there is not much I can add by way of
discussion. It would be interesting sometime to make a more therough genetic
as well as physiological atudy of phage~resistance. About all we do know now,
from the genetic side, is summarized in the 1951 CSH pp. 430-431, and in Genetics
in the 20th Century, pp. 276-278. I have had in mind to do a more thorough
study of the interactions of different V, alleles in heterozygotes, but none of
my students so far worked up very much ifterest in this. This kind of analysis
should be paralleled by a more exacting study of allsorptive properties of the
different genotypes than we have felt we could do. On the other hand, the T phages
are probably not the best material for receptor studies; I think rather clearer
results, from the point of view of extraction of the recpéors, could be gotten
with phages for the mmencemmmtfien better defined somatic and K antigens of other
BE. cold or Salminella strains/ than K~12 or B (which are "rough" as can be).

I was particularly lpressed by your synthetic lysin (the dimethyl aminoethyl
acrylate)—- doas this actually lyse and clear the B cultures? As is obvious,
such a reagent might have a great many applications, apart from phage work: to
mention two offhand, to lyse E. coli for enzymatic studies, and as a selective
agent in mtation, recombination studies, etc. If it works so cleanly, is it
available for further trial? Boris Rotman is here this year to work on the
curious "activatioh" of lactase when coli cells are extracted, or simly treated
with henzene or pentanol. It would be interesting tc determine whether this lysin
also "activates"; phage lysates are supposed to have full lac&ase activity. If it
would be more convenient, I wopld write to W.¥. Davis Siam, but I thought I might
try to beg some from you first. Dr. Rotman will be in the lab. most of the time
we're away.

Sincerely,

Joshua Lederberg