Among the many topics that discuss the Nobel Prize controversy, many people will mention Rosalind Franklin. Despite her indelible contribution to uncovering the structure of dna's double helix, she was bound by the times and often referred to as the "dark lady behind DNA." Thankfully, her name and scientific contributions are now becoming known to more people.
But to this day, what many people still don't know is that Franklin is not the only female scientist who has made key contributions in the exploration of the structure of DNA. It was the research of another female scientist that laid the groundwork for Franklin's work.
Her name was Florence Bell (later renamed Florence Sawyer). In the words of some scientists, Bell may be the real "Lady of Darkness."
The female scientist explains...
On 23 March 1939, the Yorkshire Evening News reported a news story that seemed unusual at the time. "Miss Florence Bell, a 25-year-old Cambridge graduate," was presenting a fibre testing method for wool at a scientific conference in Leeds. Apparently, the focus of this report is solely on the fact that she is a woman pursuing a career in science.
The Yorkshire Evening News reported on Bell in 1939. | Image credit: University of Leeds
What came up with the title "Women Scientists Explain" and the readers of the newspaper did not know was that the physicist had quietly laid the groundwork for one of the most important scientific milestones of the 20th century in her doctoral studies.
Bell's doctoral dissertation had several chapters describing the structure of protein fibers in jellyfish, shark fins and hair, which seemed to be an unimaginable milestone in biology at the time.
In addition to this, there is another chapter that stands out. This part of Bell's research explains how X-rays could be used to reveal the regular and ordered structure of a biological fiber, then known as thymonucleic acid.
Today, thymic nucleic acid is also better known as DNA, or DNA. Bell's X-ray method became an important tool, eventually revealing the now-known structure of the DNA double helix.
New X-ray analysis methods
Born in London in 1913, Bell became a female student studying natural sciences at Gordon College, Cambridge, studying chemistry, physics and mineralogy.
After leaving Cambridge in 1936, Bell spent a brief time in Manchester with Lawrence Bragg. Lawrence was awarded the 1915 Nobel Prize in Physics with his father, William Bragg. They showed how X-rays could be used to reveal the arrangement of atoms and molecules in simple crystals, such as salts.
In 1937, Bell was recommended by Prague to the University of Leeds as a research assistant to physicist William Astorbury.
Bell and Astebury at the University of Leeds. | Image credit: University of Leeds
Astebery was now working to apply Prague's method to the study of wool and other biological fibers. His X-ray studies of proteins in wool fibers show that they are structured like a chain of molecules, connected by smaller chemicals called amino acids. This molecular necklace can be stretched or compacted.
While this may seem inconsequential, it turns out that the deformation of these proteins is crucial to understanding their function. Astorbury's study of wool has changed our understanding of biology at the molecular level.
Due to his success in wool, Astebery began working on other biofibers. To do so, he needed a pair of hands that were proficient in this new method of X-ray analysis. The owner of these hands is Florence Bell.
Astri sometimes called Bell "the devil's advocate" because she not only possessed great experimental skills, but also had a keen intellect and was often willing to challenge his ideas. Under the influence of the times, Asteberry also thought that science was a "male-only" job, and it was clear that Bell had subverted his ideas.
He tasked Bell with X-rays to study DNA. Taking an X-ray image is not easy. It takes 10 hours of exposure and works in a dark room close to a high-pressure, high-temperature X-ray tube.
But Bell's superb skill and perseverance paid off. In 1938, based on X-ray images she had taken, she and Asterbury proposed an early model of the structure of DNA. This model provided an important foothold for later scientists.
In 1938, Florence managed to take an X-ray photograph of DNA, which Astri described as "the instrument chosen in the Creation Symphony." | Image credit: University of Leeds
"Housewife"
But it's a great pity for the scientific community that bell's DNA research work was in full swing when her research came to an abrupt halt.
With the outbreak of World War II, in 1941 she was drafted into the Women's Auxiliary Corps of the Air Force as a radio operator. She is said to have conducted early research on radar (radio detection and ranging) technology during her service.
At the same time, Astridbury always wanted Bell to stay in his lab and fight for it. He had written to the British War Department saying that without Bell's help , "he could barely continue his research". The University of Leeds even extended her position so that she could continue to work after the war.
But Bell never returned. After marrying an American soldier, she submitted her resignation to the University of Leeds and immigrated to the United States, where she became an industrialist.
Later, she gave up her career to take care of her four children wholeheartedly. When she died in 2000, her occupation on her death certificate was recorded as a "housewife."
Bell's son once recalled that in the last days of Bell's life, she liked to say that one of the greatest achievements of her life was to become the first woman in the Royal Air Force to wear trousers.
Of course this is Bell being humble. Studying DNA through X-rays, Bell not only provided an important foothold for James Watson and Francis Crick's model, but also paved the way for Franklin's famous "Photo 51."
Appendix: TIMELINE OF DNA Structure Discovery
1869: Swiss scientist Friedrich Michel isolates a gray, weakly acidic substance from the nucleus of a white blood cell, which he calls a nuclide, which was later shown to be DNA.
1931: Based on estimates of the chemical composition of DNA, chemist Fibas Levine proposes that DNA is made up of simple repeating units of four chemicals. This is known as the tetranucleotide hypothesis. At that time, many scientists concluded that DNA was a very dull repetitive molecule, so it was a candidate for a nearly impossible carrier of genetic information.
1938: Bell and Asteberry conduct X-ray studies of DNA fibers, demonstrating that X-ray crystallography can be used to reveal the molecular structure of DNA.
1944: American microbiologist Oswald Avery and his colleagues Marklin Markkati and Colin McLeod discover that DNA can impart nonviral pneumococcal pathogenic abilities. This is the first strong evidence that DNA may carry biological information.
1950: American biochemist Ervin Chagolf uses a chemical analysis method called distributed chromatography developed by Azil Martin and Richard Singer in the laboratory of the Wool Industry Research Association in Leeds, overturning the idea that DNA is just a boring, repetitive molecule and opening up the possibility that it may carry biological information through its chemical composition.
1951: A year before Rosalind Franklin and Raymond Gosling took the famous "Photo 51", Elwin Betton took X-ray images of the same DNA while working on the newly formed Biomolecular Structure Department at the University of Leeds.
1952: Franklin and Gosling use X-ray crystallography to obtain photographic images of DNA. This image shows a pattern of black spots arranged in a cross shape, which is very striking. The photo, dubbed "Photo 51," suggests that the molecule is coiled into a spiral, one of the important clues to determine the structure of DNA.
1953: Watson and Crick publish a model of the structure of the DNA double helix in nature. This structure explains how molecules replicate biological information from one generation to the next.
1962: Watson, Crick, and Maurice Wilkins are awarded the Nobel Prize in Physiology or Medicine.
Source: Principles
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#创作团队:
Compile: Takeko
Typography: Wenwen
#参考来源:
https://theconversation.com/florence-bell-the-housewife-who-played-a-key-part-in-our-understanding-of-dna-175220
https://alumni.leeds.ac.uk/florence-bell
https://www.bshs.org.uk/florence-bell-the-other-dark-lady-of-dna
#图片来源:
Cover image: MaxPixel
首图：courtesy of Chris Sawyer via University of Leeds