THE ROCKEFELLER INSTITUTE
FOR MEDICAL RESEARCH

667TH STREET ANP YORK AVENUE
NEW YORK 21. N. Y.

November 17, 1952

Dear Josh:

The weather played us a mean trick and I was most disappointed. Had hoped
that iffyou had to be weather bound it would be herdas from the airport we
were bound for a gathering at the "Sagers" which you would have enjoyed.

The 541, 565 xylose story seems to be as follows; 541 is composed of a mixture
of predombnantly xyl slows (score as the transducees) a few xyl+ and still fewer
xyl-. $65 is xin all probability a mitant of the slows and therefore a two
gene difference from the wild type + and hence is only transduced to slow
by the full plus LT-2.Unfortunataly it is here that transduction fails us
techically, Study of these intermediates would possibly give @ us an independent
allogenic transformation but the selection is impossible,

Have been mulling over your last letterjon pnase variation and am disturbed
by the following. When LT-2 ~ id x- abony phase variation remains, If I
understood you it should disappear as both the recipient and the donor are in
the alternativé “released “condition, thus the suppressed antigen in the demmerrecipient
should be lost with the antigen,paralleling their relationship in FA. The
transducee having both antigens in a single cell should not migrate under the
conditions of the experimant. Since the transduction does occur and phase
variation ensues , the latter would seem to be completely cytoplasmically
initiated and controlled,although having a more or less permanent affect on
nuclear genes.

Have been doing very little with transduction of late other than checking
which of the auxotrophic singles you sent will be skable enough foo further
analysis. My time is spent grinding up spleens and determining the ratios
and total counts of virulent and avirulent cells therein, ‘The results are
beginning to come in and I believe we @ill be able to make some sense out of
both the role of heterogeneity in the bacterial population and its relation
to nutrition in this disease model, .

Bertani's results with phage superinfection seem to clarify and verify
my own conclusions with regard to the interference experiments.He found that
superinfection with a lytic variant leads to a rapid increase in the amount
of this phage present and then its dissappearance, the survivors all carrying
the parental phage.More careful analysas of own variant shows that it is
also lytic, at least for certain typhimuri Mend gallinarut™* The experiment
then answered another question for which a more direct answer would have been
impossible--Ds lytic viruses also transduce?

Received my copy of Stocker's tome today and there is little I can add
to your discussion of the publication of the flagellar story to date.I do feel
that things should either be not mentioned at all or gone into as far as results
permit.Tracks and so forth should be developed, I'm not sure of the phase varaision
story as there apparently are some inconsistencies, Further docunentation of
puage FA identity should not be included as it is quite irrelevant to the main
themeand is the subject of a paper which I was going to discuss with you had we net
this weekend.

Sincerely,

Ohi
K P jdm ordered |