6-4-1952
Dear Josh--
Thanks very much for the reprints I received today. They reminded me of a question I've been wanting to ask you.
Do you have any knowledge of any E. coli strain which will show "sex life" with E. coli A.T.C.C. 9723? This is the strain from which my E. coli mutants were derived. I wondered if you'd ever tester W-1177 with 9723. 9723 has been used by several people for different purposes.
How about E. coli B in this regard? I have a number of mutants from Gots
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and cold spring harbor derived from B.
I'm beginning to think that gene recombination would be quite useful to "reshuffle" the purine deficiencies in the same strain, for metabolic studies, and would appreciate any ideas you could pass along.
Bernie Davis recently gave me a purine-requiring strain he'd received from you, which appears quite similar to one of my B. subtilis mutants, in that it grows on guanine and diaminopurine, but not adenine. I'm wondering if you happen to have much of a supply of purine-deficient mutants, and histidine-less mutants. I'm particularly interested in ones which appear to grow [ . . . ] of the purine bases and I'm studying a relation between such a metabolic black and biosynthesis of histidine. I'd be very grateful for anything you can send me, especially in K-12 where gene recombination
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technics are available.
I'm about o embark on the job of getting double-mutants in B. subtilis, and possibly after that it may be feasible to try gene recombination with this organism. Has anyone tried any recombination work with the spore- formers?
Sorry you didn't make the Boston S.A.B. meeting. Your pal, Zinder, did and very good job of representing you, however, at the symposium.  Naturally, it could not be quite the same!
See you in San Francisco--or will you be in Rome?
Yours,
Bob Guthrie