The microbial geneticist Salvador Edward Luria would have celebrated his centenary birthday this month, and it is to him that we turn our attentions today.
Luria was born in Turin, Italy, on August 13, 1912, the second son of David and Esther Luria. As a boy, his attitude toward school was lukewarm – he received his best grades in math and literature courses, but never fully developing a passion for learning. He eventually decided to study medicine due to the influence of his parents, graduating from the University of Turin Medical School in 1935. It was during medical school, however, that he became interested in the ways in which modern physics could be used to solve problems in biology and genetics.
Upon graduating, Luria decided to combine his love for biology and physics by studying radiology. He finished physics and radiology courses at the University of Rome, where he learned about recent theories regarding genes as a molecule and also about bacteriophages, which are viruses that infect bacteria. In 1938 Luria moved to Paris, where he became a Research Fellow at the Institute of Radium. In order to escape Nazi persecution, Luria immigrated to New York in 1940 (later becoming a U.S. citizen in 1947), where he received a Rockefeller Foundation fellowship and worked as a Research Assistant in Surgical Bacteriology at the College of Physicians and Surgeons at Columbia University.
During the annual meeting of the American Physical Society in December 1940, Luria met Max Delbrück, who introduced him to the bacteriophage experiments that they would work on together later that summer, including an investigation into the mechanisms by which phage multiply within bacteria. The duo discovered that different phage strains interfere with each other when attacking bacteria.
In 1943 Luria moved yet again to Indiana University where he thrived, forming close friendships and training numerous graduate students. It was at Indiana that conducted one of his most important studies, showing that bacteria mutated spontaneously into phage-resistant forms. Later, again in collaboration with Delbrück, Luria developed the “fluctuation test” for calculating bacterial mutation rates. This work provided statistical evidence for the existence of genes in bacteria, which established microbes as suitable subjects for genetics research. The work was also a source of great recognition for Luria within the biological community.
Throughout his career, Luria was not only a scientist, but also an outspoken policy advocate, and as a result he quickly gained the attention of Linus Pauling. On May 15, 1957, Pauling wrote to Luria for the first time, asking if he would be willing to sign his name on the “Appeal by American Scientists” – the beginnings of what would become Pauling’s famous United Nations Bomb Test Petition. Pauling sent a cover letter to Luria along with a copy of the appeal, which urged scientists to support an international agreement to stop the testing of nuclear bombs in the atmosphere. Pauling wrote in the document,
Each added amount of radiation causes damage to the health of human beings all over the world and causes damage to the pool of human germ plasm such as to lead to an increase in the number of seriously defective children that will be born in future generations.
Luria supported Pauling in this effort, and so began a series of exchanges over many years in which the two scientists requested one another’s support for various political, social and environmental causes.
One such letter was penned on March 25, 1965, when Luria wrote to Pauling regarding a Vietnam War protest that a group in Boston had recently sponsored. In it, he noted his exasperation with the contemporary political climate – one which reminded him all too much of his early life in Europe.
We now feel that the time for polite questioning is past and that something more drastic and dramatic is needed. Also, most of us feel the need to bear witness publicly of our personal refusal to acquiesce in a policy that is immoral and criminal. The situation in my mind has the same nightmare quality I felt in Germany in the ‘thirties and in France during the Algerian war. In both situations not enough intellectuals were able or willing to stand up and be counted.
Luria thought that the public’s conscience could possibly be stirred if a group of National Academy of Science members resigned from the organization while issuing a public announcement stating that the action was being taken in protest of the war in southeast Asia. He asked Pauling if this would be wise and Pauling responded by stating that he would agree to resign from the NAS if nine other members also agreed.
Over time, Luria continued down his career path, first by moving to the University of Illinois and then to the Massachusetts Institute of Technology, where he served as an adviser for both the reorganization of its biology department and for the development of its microbiology department. His collaborations with Delbrück likewise continued over the course of what would become a long and successful career.
In 1969 the duo received, alongside Alfred Hershey, the 1969 Nobel Prize in Physiology or Medicine for “discoveries concerning virus replication and genetics and the importance of contributions to the biological and medical sciences.” True to his convictions, Luria donated part of his prize money to the peace movement, helping to organize the Vietnam War Moratorium in Boston. Meanwhile, the three scientists, Luria, Delbrück and Hershey, became known as the “Phage Group,” an informal assembly who worked with seven strains of bacteriophage, comparing their findings and results.
Luria continued to be engaged in the humanities as an activist well into the 1970s, during which time he participated in debates over genetic engineering, among other issues. In 1972, he also set up and directed a new center for cancer research at MIT, expanding the molecular and cellular biology programs there. All the while he wrote prolifically, a body of work which included a popular science book, Life: The Unfinished Experiment. The book was a huge success and he continued to publish essays and opinion articles on scientific and political issues until his death from a heart attack in Lexington, Massachusetts, on February 6, 1991.