- Person
- Leo Szilard
- Lived
- 1898–1964
- Field
- Nuclear physics
- From
- Hungarian-American
The story
After the Second World War, Leo Szilard, who had conceived the nuclear chain reaction and served as chief physicist at the Manhattan Project's Metallurgical Laboratory, turned to biology. He left the laboratory on 1 June 1946 and secured a research professorship at the University of Chicago that let him work in biology and the social sciences.
In 1947 he teamed up with Aaron Novick, a Chicago-trained chemist who had worked at the Metallurgical Laboratory and at Los Alamos during the war. The two men saw biology as a field that had not been explored as much as physics and was ready for scientific breakthroughs.
Together they invented the chemostat. The name comes from the idea of a static chemical environment. In a chemostat, fresh nutrient medium flows continuously into a vessel of microorganisms while used culture flows out at the same rate, keeping the volume constant. By adjusting the flow, the experimenter can set the growth rate. The cells settle into a steady state in which nutrients, cell density and other conditions stay constant, so scientists could study bacteria and their mutations under stable, measurable conditions. Szilard and Novick also developed methods for measuring bacterial growth rates.
Their experiments also led to the discovery of feedback inhibition, the mechanism by which the end product of a chain of biochemical reactions switches off its own production, much as a thermostat turns off a boiler. Feedback inhibition turned out to be one of the fundamental ways living cells regulate growth and metabolism.
Both men went on to shape the new science of molecular biology. In 1959 Novick founded the University of Oregon's Institute of Molecular Biology, believed to be the first research institute with molecular biology in its name, and he is regarded as one of the field's founders. Szilard continued biological research on topics including ageing and helped create the Salk Institute for Biological Studies.
Chemostats remain a standard tool in microbiology. Researchers use them for physiological experiments that need cells growing steadily, and for studying how microorganisms compete under controlled conditions.
Why it matters
The chemostat is still used in microbiology and biotechnology, and feedback inhibition is a core concept in biochemistry and drug design.
About Leo Szilard
Physicist who conceived the nuclear chain reaction in 1933, drafted Einstein’s letter to Roosevelt, co-built the first reactor, then campaigned for the rest of his life against nuclear war.
More about Leo Szilard
- Szilard's advice helped clone the first human cellLeo Szilard gave essential advice that, according to Theodore Puck and Philip Marcus, made their 1955 cloning of a human cell a reality.
- Leo Szilard saw the chain reaction, and rescued scholarsWaiting at a London traffic light in September 1933, Leo Szilard conceived the nuclear chain reaction; that same year he helped found a group that found posts for 2,500 refugee scholars.
- Szilard found a way to make medical isotopesIn 1934 at St Bartholomew's Hospital, Leo Szilard and Thomas Chalmers discovered the Szilard–Chalmers effect, widely used to prepare medical isotopes.
- Szilard first proposed the cyclotron and electron microscopeLeo Szilard filed the earliest known patent applications for the electron microscope (1928) and the cyclotron (1929), and one for the linear accelerator (1928).
- Szilard and Einstein invented a silent refrigeratorBetween 1926 and 1930 Leo Szilard worked with Albert Einstein on a refrigerator with no moving parts, patented in the United States in 1930.
- Leo Szilard linked information and thermodynamicsIn his Berlin research of the 1920s, Leo Szilard showed a deep connection between information and entropy, making him a founding figure of information theory.
- Szilard petitioned Truman not to bomb without warningIn July 1945 Leo Szilard drafted a petition, signed by about 70 Manhattan Project scientists, urging President Truman not to use the atomic bomb on Japan without warning.
- Szilard fought for civilian control of the atomAfter the war Leo Szilard lobbied for changes to the Atomic Energy Act of 1946 that placed American nuclear energy under civilian rather than military control.
- Leo Szilard helped rescue 2,500 refugee scholarsIn 1933 Leo Szilard helped found the Academic Assistance Council in Britain, which by 1939 had found places for more than 2,500 refugee scholars.
Sources
- Leo Szilard Wikipedia
- Chemostat Wikipedia
- Aaron Novick Wikipedia
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.