The Wellcome Digital Library project was today featured on BBC Radio 4's "Today" programme. The report by Fergus Walsh, medical correspondent of the BBC featured recordings from King's College London, Wellcome Trust and Churchill Archives, Cambridge. The report centered on the archives relating to the critical discovery of the structure of DNA and the contributions of Crick, Franklin, Watson and Wilkins respectively.
The report can be heard on the BBC iPlayer (for those based in the UK) for the next week and starts at the 02:50 mark until 02.55. (http://www.bbc.co.uk/iplayer/episode/b01hjs46/Today_16_05_2012/) or is available on the Today programme website (http://news.bbc.co.uk/today/hi/today/newsid_9721000/9721286.stm).
In the visit to King's, Fergus Walsh was given a tour of our principle vault and shown "Photo 51" alongside a number of other items in the joint Maurice Wilkins/Biophysics collection. Some of these images can be seem on his blog post (http://www.bbc.co.uk/news/health-18041884).
For our partner institutions, a photo gallery of Crick correspondence from the Wellcome Trust collection was put up on the BBC Today programme home page (http://news.bbc.co.uk/today/hi/default.stm).
Wednesday, 16 May 2012
Maurice Wilkins and the ultrasonic pursuit of the mechanisms of life
The scientific career of Maurice Wilkins did not solely focus on the structure and refinement of DNA. Having begun reading Physics at Cambridge in 1936, Wilkins went on to work on luminosity and phosphorescence and made contributions to wartime radar research in Birmingham and later at the University of California, Berkeley, on the Manhattan Project to develop the first atomic bomb. After reading Erwin Schrödinger’s seminal “What is Life?” (1944), which influenced a generation of scientists, and following a period of soul-searching following the atomic bombing of Hiroshima and Nagasaki, Wilkins decided to focus his research on biophysics – the use of physics to study biological structures. He began his work by investigating the effect of ultrasonics on chromosomes.
Wilkins’ began research on the biological implications of ultrasonic technology when he first moved back to the UK after his wartime experience in America. Whilst at St Andrews, he was talking to the Glasgow University-based geneticist, Charlotte Averback, about Hermann Muller’s work using x-rays to cause mutations within fruit flies and he wondered whether he could replicate it using another physical agent. As Wilkins states in the The Third Man of the Double Helix (2003):
“No-one seemed to have tried strong high frequency sound (ultrasonics) on chromosomes...it was a way of starting [in biophysics]; I could do it on my own and it might help us to understand how genes worked” (p91)
The aim of his experiments was to explore the effects of ultrasonics on a living cell nucleus and especially its effect on the process of mitosis. The hope was that the ultrasonics ray would cause breakage of the chromosome and provide an interesting comparison with similar breaks engendered by other agents such as x-rays.
The initial experiments typified Wilkins’ approach to science, as he constructed by himself a high power ultrasonic generator for the experiments. A paper produced by G G Selman and Wilkins published in July 1949, states that their high intensity ultrasonic apparatus could “generate and measure higher unfocused ultrasonic intensities than any we have yet found recorded in the literature” (p229, G. G. Selman & M. H. F Wilkins, "The production of high intensity ultrasonics at megacycle frequencies” in Journal of Scientific Instruments, Volume 26).
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Yet results proved disappointing: no evidence of the cytogenetical effects of ultrasonics were found despite using an array of different samples including root tips, chick heart fibroblasts and Tradescantia pollen tubes.
Wilkins was soon keen to move onto other projects when he realised pursuing ultrasonics was not worthwhile and he was asked by John Randall to take over research into how DNA moved and grew in living cells. It was this shift into microscope studies of DNA that would lead Wilkins to recognise the potential of x-ray diffraction to elucidate the structure of the molecule.
Thursday, 10 May 2012
Selecting Material for Digitisation: Glass Slides and X-ray acetates
Part of my role for the project is
to select relevant material from the Biophysics collection for digitisation.
The Biophysics collection of paper, glass plate and acetate photographic
material produced by staff members and spans from the department's inception in
1947, to 1984. My brief was to select a subset of 4000 images from this
collection relating to DNA research carried out by Maurice Wilkins and others.
The bulk of the images came from the quarter plate glass
plate negative collection that comprises of 18300 individual items. While DNA
research accounts for a significant proportion, other departmental work notably
on muscle and the structure of collagen are also represented. The DNA related
slides had to be handpicked from this larger total. Fortunately, the entire
series had been indexed by the department. During the cataloguing project in
2011, these index books were digitised and transcribed into a spreadsheet, which
made the task of selection much easier.
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| Example of index entries for the quarter plate glass negatives: The entry referenced as "867" is of particular interest as this refers to "Photo 51", the best image of Structure B DNA produced by Rosalind Franklin. |
The selection criteria used was based on my own
understanding of the collection and the brief of the project. Having worked on
the cataloguing project of the papers prior to this role, I felt confident in
my ability to determine which material should be included. For the most part
this was fairly academic as each slide indicated who created them and all
material from well known DNA researchers was selected (e.g. Wilkins, Franklin,
Gosling, Wilson etc.). When the creators’ relationship to DNA research was not
so obvious, such as visiting academics or PhD students, then I consulted the
catalogue to see whether they collaborated in DNA research. I decided to
include all work (not just DNA research) in the early years of the department
as often related project techniques and microscopy work helped shape the later
DNA research. Supplementary material relating to microscopy studies, chemical
analysis and model building and a smaller number of half plate glass plate
negatives and photographic prints were also included.
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| An example of a quarter plate glass negative: This image was referenced in the index as "2747" and shows an x-ray diffraction exposure of lithium (Li) DNA in a B configuration created by Maurice Wilkins in April 1958. |
The jewel in the crown so to speak was the third main source
of material - the x-ray acetates. Remarkably, some of the original x-ray
exposures have survived and capture the various samples, salts and techniques
that the KCL Biophysics department used in their x-ray diffraction studies of
DNA and later RNA and nuceleoproteins. It was decided early on that all the
x-rays were to be digitised, due in part due to their intrinsic value but
secondly because of their unstable physical condition. Acetate film has a
tendency to deteriorate and undergo what is known as vinegar syndrome. This is
when the acetate degrades and begins to oxidise creating a vinegar smell. The
surface often begins to warp and crack and fades the original image. The
condition is autocatalytic which means that once it has begun it cannot
be stopped with the only stabilisation solution being to isolate and freeze the
material. Many of the x-rays show the early signs of this condition (small pock
marks) but the vast majority have retained clear x-ray patterns.
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| X-ray diffraction exposure showing clear warping and peeling of the emulsion layer but retaining the x-ray pattern of DNA. |
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| X-ray diffraction exposure of DNA with typical pock marks associated with acetate deterioration |
Digitisation is the best strategy for long term preservation of this material for several reasons. Firstly, by producing a digital copy we can retain valuable content before further deterioration ensues. Secondly, the digital copy will be more accessible than the original as a high quality scan can provide a greater degree of clarity than the physical copy and thirdly by producing a digital surrogate it reduces the risk of damage from physical handling and allows for the original material to be put into cold storage.
Overall, the images selected from the Biophysics Department
are representative of the biophysical approach to genetics taken between
1947-1969.The collection provides an unprecedented record of x-ray diffraction
studies in genetics as well as fully documenting the experimental work of
Maurice Wilkins and his colleagues carried out at King’s.
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