DEPARTMENT OF GEMET!CS

.

FACULTY OF MEDICINE, CWWi UNIVERSITY

Joancho-3% Kit&u, O~aks, Japan.

cct. ZL, 1961.

Or. Ida $rskov

international Salmonella
and Xscherichia Center,
Stateas Seruridnstitut,
Copenhagen, S.
  ijenmark.

'.                     D

   Thank you for your letter of September 21. I underetand
;TOLW opinion that K-12 is not suitable for agglutination test
of F+ serum, and you have.the better male strains of E. coli
such. as C poup 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. 1 am
grateful if you could send me your anti-f .serum with your euitable
F+ *  Yfr,  and F- carrying same genetic back ground.

    PIr . Sugino and rryself recently found that our n fwctore,
do ,behave as sex-factor in K-12. F-R+ x F-R- gives recombinanta
by cell to cell contact, for example.
/?.a ,ie, ,F'rofessor J. Lederberg suggested to&me 'I I tiagine he{
Iii-. Y. drskov) will be in touch with you concerning the passibii.;ity
of his continuing an immunological. examination of the strains   '.
which are rendered fertile by the 3 factoF for coruparfson with I
the standard 7. 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
G' facilitate hi8 making such's study,---"                    I- '_/ ,

  I am hoping that if we could co-work togather on'thia, fine
as Josh has suggested, such aa genetic control on.praductf.oa ':-. .,','
of male substances in E. coli by F and R including on the-pi-oblsno..
nf repression of mating by H i;n Qie bacteria.                     -'
                                   I                          '*             
                                                 1

  I would like to ask on your opinion in this poiu't.
Please send my best regards to`Dr. Frft+#rskov. 1
                                                                

With best re&rds,.:

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