Sunday, July 25, 2010
Rosalind Elsie Franklin was born in London, England on July 25, 1920, the second of five children of a prominent Anglo-Jewish family. Her father Ellis Franklin was a partner at Keyser's Bank and her mother Muriel (Waley) Franklin was active in charity work. Growing up with brothers, both older and younger, Franklin became more interested in sports and competitions than girlish things. In 1932, at age eleven, Franklin entered St. Paul's School for Girls and at the competitive school she showed an aptitude for math and science in addition to a facility for languages.
Franklin left St. Paul's in 1936, entering Newnham College at Cambridge (one of the two women's colleges at Cambridge) to major in physical chemistry. She was awarded her B.A. in 1941 and received a scholarship and a grant to do research for a year under R.G.W. Norrish's supervision. Afterwards, with the war on, Franklin was able to find a position doing research for the newly formed British Coal Utilization Research Association. Her research involved studying the microstructure of coal. Measuring the density with different liquids and helium gas she was able to determine the amount of small pores in a sample of coal. When the coal was heated to carbonizing temperatures the amount of pores increased. Her results made it possible to predict the behaviour of different coals with a high amount of accuracy. This work yielded a thesis, for which she received her Ph.D. in 1945.
After the war Franklin went to France, getting a position in the lab of Jacques Mering where she learned the technique of X-ray crystallography. X-ray crystallography is a technique in which the atomic structure of a substance by subjecting it to X-ray bombardment. The X-ray photons are diffracted by the substance and are detected by a photographic plate. The atomic structure of the substance being investigated can be determined by measuring the angles of diffraction. Franklin applied used this technique to continue her studies of carbon structure. Franklin liked the intellectual and egalitarian nature of French culture, preferring it to the middle class English customs of her upbringing.
In 1950 Franklin returned to England to work in the lab of John T. Randall at Kings College London. She was assigned to work with Maurice Wilkins to use X-ray crystallography to study DNA. The much less collegial atmosphere at Kings College did not suit Franklin and she and Wilkins did not communicate. Franklin worked on her own, with graduate student Raymond Gosling, taking increasingly clear pictures of DNA. From her pictures she realized that DNA could assume two different structures, which she labeled A and B. The A form is seen in drier conditions than the B form, the B form being the form that is found en-vivo. Previous researchers had been unable to determine an exact structure because they had been analyzing a mixture of the two forms.
Unknown to Franklin, Wilkins showed one of her diffraction photographs to Francis Crick and James Watson who were at Cambridge also working to determine the structure of DNA. The photograph provided crucial information that allowed them to publish their structure for DNA in 1953. Although they remained cordial with Franklin, Watson and Crick never fully acknowledged the help they received from Franklin in determining their structure.
Unhappy working at Kings College, Franklin arranged to transfer her fellowship to work at the crystallography laboratory of J.D. Bernal at Birkbeck College. There Franklin used her skill with X-ray crystallography to study viruses, particularly the tobacco mosaic virus (TMV) and determined that the virus' genetic material (RNA in the case of TMC) is embedded in the inner wall of its protein shell. In the Fall of 1956 Franklin was diagnosed with ovarian cancer. She died on April 16, 1958.
Elkin, Lynne Osman; "Rosalind Franklin and the Double Helix"; Physics Today (2003)56:42-48
Maddox, Brendal; Rosalind Franklin: The Dark Lady of DNA
; Harper Collins; 2003
The Rosalind Frankin Papers at profiles.nlm.nih.gov
Sunday, July 18, 2010
Charles Palache was born in San Francisco, California on July 18, 1869. His father, James Palache, had come to California from New York as a cabin boy in 1849 lured by the gold rush, and there set up as a merchant. His mother, Helen Whitney, had come to California in a covered wagon from Green Bay, Wisconsin. Charles, a sensitive child, showed an early interest in natural history and avidly collected rocks. During his childhood his family moved across the bay to Berkley. In 1887 he graduated from Berkley High School and entered the University of California Berkley, selecting to study mining, because of the emphasis on natural history in the program. He soon found out that he was "repelled by the prospect of life in the mine" but when assigned to make a map of the Berkley hills he found that he enjoyed the work. During the assignment he found a set of ponds up in the hills in a place unlikely for ponds. He returned to the ponds and mapped them with his professor. The lakes were actually a result of the rift that would eventually cause the 1906 San Francisco earthquake.
Palace graduated at the top of his class and stayed at Berkley to earn his doctorate under Andrew C. Lawson. In 1894 Palache went to study in Europe where he studied crystallography under Victor Goldschmidt, laying the foundation for the work he would pursue for the next fifty five years. Palache, after returning to California, received an offer to become an assistant at Harvard University. In 1899 he took part in the Harriman expidition to Alaska, postponing his wedding in order to do so. In 1902 he was named assistant professor, professor in 1910 and professor emeritus after his retirement in 1941.
Palache's major field of work at Harvard was morphological crystallography. There is scarcely a crystallized mineral that he did not work on. He was the first person to bring a Goldschmidt two circle reflecting gonometer to a America. A gonometer is an instrument used to measure the angles of crystals. Palache published over 150 papers on crystallography. In 1919 he helped organize the Mineralogical Society of America and two years later served as its president. He was elected to the National Academy of Science in 1934. In 1936 he was elected president of the Geological Society of America and in 1937 he was the first recipient of the Roebling Medal given by the Mineralogical Society of America. Palache's greatest achievement however was the comp
Plache's greatest achievement, however, was the preparation of the 7th edition of the Dana System of Mineralogy using the new tool of X-ray crystallography. This is the standard handbook used to identify minerals. The first volume was published in 1944 and the second in 1951.
Palache died on December 5, 1954
Daly, Reginald;"Charles Palache: 1896-1954"; Biographical Memiors Vol. 30; National Academy Press; 1957
Frondel, Cliford; "Memorial of Charles Palache" at frankin-sterlilnghill.com
Charles Palache: 1896-1954 at pbs.org
Sunday, July 11, 2010
Sunday, July 4, 2010
John Howard Northrop was born on July 5, 1891, in Yonkers, New York. His father John Isaiah Northrop, a tutor in the zoology department at Columbia University was fatally injured in an explosion and fire at the zoology museum shortly before his birth. His mother, Alice Rich Northrop, was a botanist and naturalist and helped introduce nature studies into the curriculum of the New York City Schools.
Northrop excelled in chemistry and mathematics in the public schools of Yonkers, New York. Northrop attended Columbia University, studying chemistry and zoology, and was an outstanding member of the rifle and fencing teams, graduating with a B.S. in 1912. He continued at Columbia, earning a M.A. in 1913 and his pH.D. in 1915, completing a thesis on "The Organic Phosphoric Acid of Starch".
After finishing his doctorate, Northrop accepted an offer to work under Jaques Loeb at the Rockefeller Institute. He became an associate a the institute a year later and with the exception of a year spent as a Captain in the Chemical War Service (1917-1918) he remained at the institute becoming an associate member in 1920, a member in 1924. In 1949 he was appointed professor of bacteriology at the University of California and was later appointed professor of biophysics.
Northrop's work at Columbia concerned carbohydrates. Later, working under Loeb, he did research on Drosophilia, examining the relationship between environmental factors and heredity. During World War I, Northrop worked on ways of producing chemicals that were in short supply including acetone. In 1920 Northrop isolated pepsin using a method previously described by Cornelius Pekelharing, but was unable to crystallize it. When in 1926 James B. Sumner crystallized urease, Northrop took another look at the problem. In 1929 Northrop was able to crystallize pepsin and after numerous attempts to separate the enzyme activity from the protein, he was able to conclude that enzymes are proteins. At the time there was doubt about the nature of enzymes, and it was Northrop's work that was able to conclusivley demonstrate the protein nature of enzymes.
Enzymes are the catalysts that allow chemical reactions to take place in biological systems. Pepsin is a digestive enzyme that breaks down proteins into amino acids. Pepsin is secreted by the chief cells of the stomach in an inactive form called a zymogen. Hydrochloric acid, secreted by the parietal cells of the stomach cause the inactive pepsin (called pepsinogen) to cleave itself, leaving the active form of the enzyme.
Northrop is the author of Crystaline Enzymes published in 1939 and was the editor of the Journal of General Physiology for a number of years. In 1949 Northrop, along with Sumner, were awarded the Nobel Prize for Chemistry for their work demonstrating the protein nature of enzymes. Other awards Northrop has won include the Stevens Prize (from Columbia) in 1931, the Chandler Medal in 1936, the Elliot Medal in 1939 and the Alex Hamilton Medal in 1961. He also has honorary doctorates from the Universities of Harvard, Columbia, Rutgers and Yale.
Northrop died on May 27, 1987..
Herriott, Roger M.; "John Howard Northrop"; Journal of General Physiology (1981) 77:597-599
Herriott, Roger M.; "John Howard Northrop" in Biographical Memiors, Vol. 63; National Academy Press; 1994
John H. Northrop, Nobel Biography