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ty SOFD FROM THE ORIGINAL IN THE
REPRODUCED FROM THE ONIGE ae
CALIFORNIA iNSTITUTE OF -TECHT OLOGY ARCHIVES
FOR REFERENSE OLY

June 9, 1042
PERMISSION NECESSARY FOR REPRODUCTION )

Dear Liax:

I have just seen our peview in Advances in
aNgymolo-y;.e Itd lite a reprint of it, if you have any lerc.

Tou may have heard thet se are soins to Stenlord
next month. I'm Going to work with Seacle on the proble::
of the fuscure. In case you haven't heard, the Set-up is
88 follows: she nold’ Veurospora requires, in addition to
aC source end inorganic salts, only one growth factor-~
Diotin.e All other Lactors are Synthesized by the orsan=
isme By irrediation, Beadle and tatum have been able to
induce rutations which require other factors in edition
to biotin. whe mtants can be isolated, crossed with one
another, etce ‘he mutations are inherited as recessives,
So far, the: have obtained mutations for thiamin, Bs, pan-
tothenic, tro nicotinics, and helf a dozen anino ecids.
In adcition, there are sone Waich require unknorm factors.
the importence of this ig obvious. In addition to being
& Systematic method for the discovery of new growton factors,
each mutant is an assay orgenism for the factor in question.
this in itself is of great usefulness for ‘mown substances
wnose assay is difficult (€eSe, BG). Where are a dozen other
variations end ansles to the problem. For example, this
is very favorable material for Studying the catalytic role
of vitamins in cell metabolism. ind then, of course, there
is the problen of the future--the chemistry of th Sens

+he whole thing is so beautifully conceived,
the choice of organism so verfect both for chemicel and
genetic analysis, the tecnnicues for handling it so precise,
that it is indeed a nlarvellous creation to behold. Beadle
is really an experimentalist of the first magnitude.

Dave, by the way, is already at Stanford. Ke
is working on the isolation of the unlmnown factors,

Erik is going to Pittsburgh--my native heethe-
in September. ie will be at the Vest Penn Hospital, workins
on the enzymatic aspects of sulfa drugs. He got his PheD.
this year, ,

Pearl sends lovee Present my compliments to
Lannye

/ Uli _ Horonah