December 14, 1952

Dear Seymour shu

I've finally gotteh time to collect the few purineless cultures we've had
in E. coli K-12. I hops they will be of some use for you.

Gots has asked for these also, presumably for other purposes. Would peu
be kind enough to make them available to him?

Sincerely
vy, PUP

Boum
The following cultures are enclosed. All are derived from B. coli K-12

in one or two steps.

No. History Responses

W-9 recordedat Yale U. as bictin; uracil
58-5417 (Tatum)

Well recorded at Yale U. as biotin; adenine
5€-5273

W-589 received from Luria as tryptophane ; adenine
175-12

W590 received from Luria as comicx to purines and pyrimidines
1094

W—1278 received fron Novick hypoxanthine, adenine or guanine

not xanthine

These cultures have not been tested for a very long time. Please inform me
of any discrepancies.