TEL. FJ 0177

THE WALTER AND ELIZA HALL INSTITUTE

OF
MEDICAL RESEARCH
DIRECTOR C/o ROYAL MELBOURNE
Sin MACFARLANE BURNET F.Rs. HOSPITAL POST OFFICE,
MELBOURNE,
VICTORIA, AUSTRALIA
13th June, 1958,
Dr. J. Lederberg, _ Ae
Genetics Building, bam
Department of Medical Genetics, ee

School of Medicine,
University of Wisconsin,
MADISON 6.

Dear Joshua,

It was good to receive your letter of June 4 and to know you have such
a fine lead on the possible specificity of the muco- polysaccharides in the role
of bacterial conjugation. This opens up for you a wonderful avenue of work of
which { am sure you will take full advantage.

I am concerned that you have not received either of the lots of KDE
which I have sent you. The last lot despatched from here on Feb. 26 was registered
and we have asked the postal authorities to check on what happened to it. Meanwhile
f am sending another lot labelled slightly differently as the customs may be side
tracking this material.

The enclosed photograph is of crystalline RDE which Gordon Ada and I
succeeded in obtaining last week. It seems to be approaching 95 to 100% purity
and has very high activity. If you get promising results with the material I am
sending you we will let you have some of this crystalline material. Incidently
I doubt whether any local RDE obtainable for a while will have sufficient titre
or the required degree of purity for your work. Gordon and I can probably let
you have sufficient material provided we can get it to you safely.

We are beginning to make a little progress with the mechanism of induction
of the enzyme by neuraminic acid derivatives. Feldman's Medium did not prove entirely
satisfactory because on prolonged incubation the RDE rapidly disappeared. This
difficulty has been largely overcome by the addition of small amounts of acid treated
peptone to the medium in which there is only a low level of enzyme produced in the
absence of the induced substance,

/2.
Although this is not an entirely synthetic medium we think it will
allow us to make some observations on the induction phenomenon. ‘We will
let you have a copy of our results when they are obtained.

I do hope this material gets through to you this time. Please let me
know if it has not arrived within a week of this letter.

Gordon and all the others send their regards and best wishes to you +
I believe Gus has written to you recently about the Spirillum cultures.

Kindest personal regards.

Yours sincerely,

KA An,