UNIVERSITY OF ILLINOIS
DEPARTMENT OF ENTOMOLOGY D
DIVISION OF BIOLOGICAL SCIENCES ecember 29,1951
303 HARKER HALL
URBANA, ILLINOIS

U.S.A.
Dr. Joshua Vederd erg
Department of Jenetics
University of Witna—

adison, “isconsin
Dear Dr Jederberg,

Thank you for your letter.Only a few weeks ago I had the opnortinity
of talking to Dy, B.D.Davis during a meeting of the A,C.S, at Austin, Texas.
You may perhaps (Cora that Bp hag not only been isolated but also
chemically identified as carnitine, a betain which has been isolated
before from meat extracts.e have also now fomd that E.coli ,when grow
synthetically,does not contain Bp,or could only contain ik in the minutest
amdunts.It is therefore not surprising that our effo to produce
a Buléss mtant were unsuccessful. Ve have no microbial assay of
Bp, bub there is a vague possibility that we would succeed with Neurésnora
where we failed with coli.

As to your query about microsymbionts eCe, there has been very little
work in this field ,except for some new work in Germany which has
not yet been vublishedProfessor Puchner is writing a new book which
should be out early in 2952 ( at Brkheuser,2asel) and there was a
symposium on symbiosis during the International Congress of Entomology
at Amgterdem last summer at which I wag one of the sneakers. The full
reprott of this symposium will appear very soon (if it has not already
appeared) in a dutch entomolosical Jonmal. You will find the most
recent references,mostly to unnublisheé work, in the vavers given by
A.Koch and L.Zothe The latter did a lot of work on the question of
nitrogen fixation by symbionts ( which neither Wig¢lesworth nor myself
believes to be true), I think instead of laboriously collecting these
few references for you you will find them conveniently presented in that
symmosium report,and later in Buchnerg book. The full account of the
work reported in Science 1950 has not yet been written up for publication,
but has been Testing in a drawer of my desk. I do not know of any other substi¢

tution experiments,
Yours sincerely
, /. oe ae

G. 5 . Fraenkel