DEPARTMENT OF GENETICS
FACULTY OF MEDICINE, OSAKA UNIVERSITY

Joancho-33, Kitaku, Osaka, Japan.

Oct. 21, 1961.
Dr. Ida Orskov

International Salmonella
and Escherichia Center,
Statens Seruminstitut,
Copenhagen, S.

Denmark.

Dear Dr. Orskov ;

Thank you for your letter of September 21. I understand
our opinion that K-12 is not suitable for agglutination test
of F+ serum, and you have the better male strains of BE. coli
such as C rroup 100 which could be used for f+ test.

I would like to test if the R factor repress the mating
capacity of your male strains, and if it is repressed, then
we can test the possibility which we discussed before. I am
grateful if you could send me your anti-f serum with your suitable
F+, Hfr, and F- carrying same genetic back ground.

Mr. Sugino and ryselif recently found that our n factors
do ,behave as sex-factor in K-i2. F-R+ x F-R- Rives recombinants
by cell to cell contact, for example. *
Ree onofessor J. Lederberg suggested to me " I imagine he( :
vr. F. G@rskov) will be in touch with you concerning the possibility
of his continuing an immunological examination of the strains
which are rendered fertile by the R factor for comparison with -
the standard F. As it is quite unlikely that anyone in the ‘world |
could do this particular immunological work so well -and there
is every reason to believe that it will be quite adventageous: .
to’ facilitate his making such a study.---" cae

I am hoping that if we could co-work, togather on this, line
as Josh has suggested, such as genetic control on production -.. ee
of male substances in E. coli by F and R including on the “Broblen .
of repression of mating by R in this: bacteria.

t
-

I would like to ask on your opinion in this point.
Please send my best regards to Dr. Fritz. Prskov. - .

With best regards,

Yours Cael .
een ate

nori Hirota —
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