Siegel was one of the researchers that Franklin met during her 1954 visit to the United States. In this letter, he described
another sample of TMV he was sending her for x-ray diffraction analysis.
Number of Image Pages:
1 (60,175 Bytes)
1955-02-23 (February 23, 1955)
University of California, Los Angeles. College of Agriculture
Original Repository: Churchill Archives Centre. The Papers of Rosalind Franklin
Courtesy of the Churchill Archives Centre.
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Thank you for letting us know of your interesting results. The strain which you have is U2. We sent it to you as a 1.7 percent
virus solution in 0.1 ionic strength cacodylate buffer.
I am sending you some of our common strain which is referred to in our publications as U1. It is also made up in cacodylic
acid buffer and is at a concentration of 31 mg per cc. We prepare our virus solutions by differential centrifugation of a
You will notice that the preparation of U1 that we have sent is murky brown in appearance. This is due to an adsorbed host
nucleoprotein. Should you desire to work with a colorless preparation the adsorbed host nucleoprotein can be gotten rid of
as described in the accompanying separate. None of the properties that we have examined appear to be different for the colored
and colorless preparations, such as infectivity, electrophoretic mobility, UV sensitivity, UV absorption, etc.
We would very much be interested in hearing of any further progress that you make with this material.