- Meselson , Matthew Stanley
- (1930–) American molecular biologistMeselson, who was born in Denver, Colorado, studied liberal arts at the University of Chicago and physical chemistry at the California Institute of Technology, Pasadena. After he obtained his PhD in 1957 he remained at the Institute until 1960 when he moved to Harvard, where he served from 1964 as professor of biology and from 1976 as Thomas Dudley Cabot professor of natural sciences.In 1957 Meselson, in collaboration with the American biologistFranklin Stahl (1910––sp;–sp;), conducted one of the classic experiments of molecular biology, which clearly revealed the semiconservative nature of DNA replication. It seemed likely that when the double helix of DNA duplicated, each new helix, and hence each daughter cell, would contain one DNA strand from the original helix; in the jargon of the time, replication would be semiconservative. The other possibility was that one daughter molecule would contain both the old strands and the other daughter molecule both the new strands – conservative replication.Meselson and Stahl grew many generations of the bacteriumEscherichia coli on a simple culture medium containing ammonium chloride (NH4Cl), labeled with the heavy isotope of nitrogen, 15N, as the only nitrogen source. They then added normal 14N nitrogen to the medium and removed bacterial cells at intervals, extracting their DNA by ultracentrifugation. The density of the DNA in successive samples could be determined by the method of equilibrium density gradient centrifugation, in which samples of differing density diffuse into discrete bands corresponding to their own effective density. Ultraviolet absorption photographs of these bands allowed the concentration of DNA in each band to be determined. The results showed that (following the introduction of 14N) after one doubling of the E. coli bacteria all the DNA molecules contained equal amounts of15N and 14N, i.e., they were all half labeled. After two generations there were equal amounts of half-labeled DNA molecules and wholly 14N molecules. This effectively demonstrated that replication is semiconservative. The results were published in the Proceedings of the National Academy of Sciences, as The Replication of DNA in Escherichia coli (1958).Meselson has also worked with Sidney Brenner and François Jacob on the mechanism of viral infection. In 1961, working with the virus T4, they showed that on invasion of a host bacterial cell the viral DNA releases messenger RNA, which, when it arrives at the host ribosomes, instructs these to make viral protein rather than bacterial proteins.
Scientists. Academic. 2011.
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Meselson, Matthew Stanley — Meselson , Matthew Stanley … Scientists
Meselson, Matthew Stanley — born May 24, 1930, Denver, Colo., U.S. U.S. molecular biologist. He received his Ph.D. from California Institute of Technology; from 1964 he taught at Harvard University. He conducted research with Franklin Stahl that showed that, during cell… … Universalium
Meselson, Matthew Stanley — (n. 24 may. 1930, Denver, Col., EE.UU.). Biólogo molecular estadounidense. Obtuvo un Ph.D. en el Instituto Tecnológico de California; desde 1964 enseñó en la Universidad Harvard. Junto con Franklin Stahl realizó investigaciones que demostraron… … Enciclopedia Universal
Matthew Meselson — Matthew S. Meselson Born 24 May 1930 (1930 05 24) (age 81) Denver, Colorado, USA Citizenship USA … Wikipedia
Meselson — Matthew Meselson. Matthew Stanley Meselson (* 24. Mai 1930 in Denver, Colorado) ist ein US amerikanischer Genetiker, Biologe und Chemiker. Leben Meselson studierte Chemie an der Univer … Deutsch Wikipedia
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Stanley — /stan lee/, n. 1. Arthur Penrhyn /pen rin/, (Dean Stanley) 1815 81, English clergyman and author. 2. Edward George Geoffrey Smith, 14th Earl of Derby, 1799 1869, British statesman: prime minister 1852, 1858 59, 1866 68. 3. Francis Edgar, 1849… … Universalium
Matthew — /math yooh/, n. 1. one of the four Evangelists, a customs collector from Capernaum, summoned to be one of the 12 apostles: originally called Levi. Matt. 9:9 13. 2. the first Gospel. Abbr.: Matt. 3. a male given name. * * * (as used in… … Universalium
Matthew — (as used in expressions) Arnold, Matthew Barrie, Sir James (Matthew) Boulton, Matthew Flinders, Matthew Hale, Sir Matthew Lewis, Matthew Gregory Meselson, Matthew Stanley Perry, Matthew C(albraith) Petrie, Sir (William Matthew) Flinders Ridgway,… … Enciclopedia Universal
Matthew Meselson — Matthew Stanley Meselson (* 24. Mai 1930 in Denver, Colorado) ist ein US amerikanischer Genetiker, Biologe und Chemiker. Leben Meselson studierte Chemie an der University of Chicago und schloss sein Studium am California Institute of Technology… … Deutsch Wikipedia