February 23, 1953

Dear Ben: (Us leon)

Do you know Dr. Alex Keynan? I had a letter from Goldwasser
(at the "Israeli Institute for Biological Research'— what is
this?) inquiring about the possibility of our having Keynan
as a postdoctoral fellow next year. If you can give me your
impressions of him, I would be pleased to mve them

Personally, nothing mach new here; professionally you have
our reprints. We did not quite understand what you meant about
Elie Wollmann "mediating" @or us amidst the group at Paris.

We keep hearing feuspqam about you now and then. Is it your
sister who has been working in Plant Pathology here lately? I
understand you are partly going back to your studies on the blue-
pigmented forms. Had you noticed A. J. Weil's observation that
chloromycetin inhibits the formation of prodigisein? Does this
make any sense on any enzymatic scjeme? What did you actually
do at Paris— are you going to work on adaptive enzymes?

With best regards

t f
Blo Leh ee
~ Joshua Lederberg

P.S. I had a letter lately from Snell asking for another
culture of Y=117 (arginineless), and gather he is resuming
studies with canavanine. He mentioned that peptides seem more
active in reversing the inhibitioh than free arginine, as one ”
might expect of a competitive inhibitor dor arginine assimilation
into pepeides.