F. C. Bawden (1908-1971) was a pioneering plant pathologist and virologist based at the Rothamsted Experimental Station in
England. He and N. W. Pirie were longtime collaborators in plant virology. During 1957 Franklin's team studied a number
of different virus samples provided by Bawden, and elucidated their structures. In this letter, Franklin consulted him about
the problems involved in preparing samples of potato virus for X-ray diffraction photos.
Number of Image Pages:
1 (90,806 Bytes)
1958-03-20 (March 20, 1958)
Bawden, F. C.
Rothamsted Experimental Station
Original Repository: Churchill Archives Centre. The Papers of Rosalind Franklin
Reproduced from the Franklin Collection at the Churchill Archives Centre with the permission of the copyright holder.
Many thanks for your letter, and for taking so much trouble with the manuscript. I agree entirely with the more important
of your amendments and with almost all the minor suggestions as well.
I should very much like to look at some potato X, and could start work on it the day I receive it. I like to work with pellets
of about 10 mg; so if I were successful at the first attempt, which is rather unlikely with a new virus, 10 mg would be all
I should need. It would be nice to have enough for several attempts if you can spare it.
The major problem, from my point of view, is to find from what solvent (pH and salt concentration) a pellet with good mechanical
and optical properties can be obtained. With TMV we use 0.02 M phosphate buffer, pH 7.0. About 2 years ago Jim Watson had
a small amount of potato X, and our experience with this was that the pellet formed a rather rigid gel and could not be re-dispersed
in distilled water. Possibly the trouble was due to the virus not being adequately purified. What we need is a pellet which
(after some dilution, if necessary) can be made to flow while the virus concentration is still high. (We, have a refrigerated
centrifuge). So it would be a great help if you would make same recommendations as to desirable buffers and concentrations.
One further point. The, capillary tubes which we normally use are of a borosilicate glass (transparent to X-rays). They have
a slight alkaline reaction. This is not enough to harm TMV, but causes TMV protein to depolymerise. If it is likely to be
harmful to potato X I could use Pyrex tubes instead.