THE COLORADO FOUNDATION FOR RESEARCH IN TUBERCULOSIS

 

 

GERALD B. WEBB MEMORIAL BUILDING, AT THE UNIVERSITY OF COLORADO MEDICAL CENTER

4200 East Ninth Avenue
Denver 20, Colorado

February 19, 1957
ATR MATL \A

Dr. Joshua Lederberg
Tepartment of Genetics
University of “isconsin
Madison 6, Wisconsin

 

Dear Joshua and Esther:

Enclosed you will find summaries of two experiments on UV of HFT lambda, which
I long ago rromised. I have not written a text summary to go with them because
I believe we have alreadv discussed the significant results. “hen I am able to
make new lysates (having troubles) I will repeat them in entirety and also make
more extensive analysis, especially of transductions to *% recipients. I have
just returned from three days at Caltech, where I discussed these experiments
(as well as my growth experiments) with the people attending the meeting. It
seems that Arbe@ has found similar UV results recently. However, I was able to
present the dates on these experiments and to get the impression across that the
people in Gen-va had not come on something new.

The meeting was quite good, although two nights and a day in the desert in the
middle of twem made me so tired that I did not do well in discussing my data.
Keiser and Weigle were very pleasant and I am planning to return for a couple of
weeks to do some experiments with Veigle, vrobably on the growth of transducing
particles. He is doing quite well and has confirmed most of our observations.
He has now isolated HFT 17, 27 with the lambda mutant he is using. This mutant
really grows better than we are using. He checked diets and found the low
titers we get in HFT, so there are really strain differences. I talked with
Kaiser, who is both sharp and easy totalk with, and he said that lambda 26 does
not form stable lysogenics and that you (or we) should check the origin of the
strains so labeled. There is a lysogenizing recombinant between lambda 26 and

a better lysogenizing mutant which has the plaque character of lambda 26 and
this may be what we have. He was willing to send any stocks requested. If you
have not met him, I would suggest it, since he has worked out a great deal of
lambda genetics, and has 2 great deal of information. From the standpoint of
coli genetics he hes a Jacobian view, but this is chiefly owing to the fact that
he has not heard of other data. I hope to see more of him this summer, since
his wife comes from Ft. Collins and he will »%e vacationing there.

I have not been productive of late, since it has been a period of nothing going
right. I hope that my trip has changed it all and I again will be able to get
results of mzaning. IJ will send along some data (old) on crossing heterogenotes
in a few days and try once again to put my data for our papers in final forn.

The culture of “116, arrived broken but we were able (easily) to isolate a
Gal-M~ clone from it. The old data suggested that W2281 gave a large number of

 
Dr. Joshua Lederberg
February 19, 1957
Cont'd

Lpt/S ransductions with LFT lysates. I wanted to see if this was a property of
the Lo” of W2281 or of some other marker in the W1210 line. I planned to isolate
Lp® from “1210 and compare them with #2281. However, I have not obtained L
heterogenotes with fresh lysates on “2201 so that it may be that the old data

are explainable on the change of lysates with time. Weigle told me that Arbe#@
has looked at HFT lysates under the electron microscope and finds agreement to
30% between plaque titer and particle counts, so that there cannot be many non-
plaque forming particles in the lysate (or lysates?) that he looked at. This
may be good forthe S/S explanation, which I believe Weigle may be considering
nowe J did not have a chance to talk with him about this.

What is it going to be--Stanford, Berkeley or Madison? Everyone wants to know,
I suprose even yourselves.

As ever,

Ma L. Morse, Ph.D.

MLM/mb
Encls.