LURIA, Salvador Edward

(b. 13 August 1912 in Turin, Italy; d. 6 February 1991 in Lexington, Massachusetts), geneticist, administrator, and writer who won the 1969 Nobel Prize in physiology or medicine for his work on viral and bacterial genetics.

Luria was the son of David Luria, an accountant who managed a printing business, and Ester Sacerdote, a homemaker. The Lurias were members of one of the most prominent Jewish families in Turin, and Salvatore (as his name was originally spelled) attended the Liceo d'Azeglio, one of the most prestigious high schools in northern Italy. Afterward he studied at the University of Turin medical school, where he took his degree with honors in 1935. He was then drafted into the Italian army as a medical officer. After he was discharged in 1937, Luria decided against a career in medicine and undertook more theoretical studies on radiology, physics, and mathematics in Enrico Fermi's laboratory at the Physics Institute of the University of Rome.

It was in Rome that Luria began the work that would lead to major discoveries about DNA (deoxyribonucleic acid) in the 1960s, and ultimately to his being awarded a Nobel Prize in 1969. (DNA is present in the chromosomes of all cell nuclei; the distinctive double helical strand is the chemical basis of heredity and carries genetic information for most living things.) Inspired by the work of the physicist Max Delbrück, he became interested in bacteriophage (phage), viruses that infect and kill bacteria. Luria went to France in 1938 when the situation for Italian Jews deteriorated after Italy became more closely tied with Nazi Germany. He briefly did research in Paris, and then, as the German Army approached the city, fled to New York in 1940 and obtained a position at Columbia University. In the early 1940s, funded by a Guggenheim Fellowship, he worked with Delbrückat Vanderbilt University and then accepted a faculty position in the microbiology department at Indiana University in Bloomington. There he met and married Zella Hurwitz, a psychologist, on 18 April 1945. They had one son, Daniel, who became a political economist. In 1947 Luria became a naturalized citizen of the United States.

At Bloomington, Luria discovered that bacteria, like higher organisms, can mutate or change genetically, and he developed a test to detect such mutations. He exposed bacteria to phage and then identified strains that continued to grow, indicating that they had mutated to become resistant to the damaging effects of the phage. Luria later discovered that phage can mutate. This work, along with that of two other phage researchers, Delbrück and Alfred Day Hershey, brought the study of genetics down to the molecular level. The trio began what came to be called the "phage group," and had a profound impact on genetic research of the 1960s. (The phage group was a group of researchers associated with the Cold Spring Harbor Laboratory, Long Island, New York. Today's comparatively sophisticated understanding of viruses is based on the work the phage group did in the 1960s.)

In 1950 Luria moved to the University of Illinois, where he remained until becoming professor and chair of the Massachusetts Institute of Technology (MIT) Department of Microbiology in 1959. At Illinois, Luria found that phage damaged by radiation can be "reactivated" by exchanging genes with other phage. He then accidentally discovered the process of restriction, where DNA is broken down into small pieces by protein catalysts called enzymes. Restriction enzymes later were crucial tools in what became known as genetic engineering, since they allowed biochemists to cut DNA and then take the pieces and insert them into other organisms. This ultimately led to the creation of genetically modified plants and animals.

By the 1960s Luria was busy building the MIT Department of Microbiology into one of the best in the United States. Deciding that phage research had gone as far as it could, he set his sights on different problems and became interested in cell membranes. He held a series of influential research conferences to draw attention to the field, and studied a class of proteins called colicins. Colicin produced by one type of bacteria can kill bacteria of other strains. Luria and his associates found that colicin works by creating a hole in the bacterial membrane and causing a fatal leakage of salts.

By the 1960s the scientific community had come to appreciate the work of the phage group. It was clear that work on phage had opened up a new era in biochemistry and molecular biology. It also was evident that DNA was the genetic molecule, and the work of the phage group in making that obvious was finally appreciated. In 1962 one of Luria's students, James Watson, received the Nobel Prize along with Francis Crick for discovering the structure of DNA. It was just a matter of time before Luria's earlier work on mutations in the DNA in bacteria and phage would also be recognized. Finally, in 1969, Luria was awarded the Nobel Prize in physiology or medicine along with the other two founders of the phage group, Delbrück and Hershey. The consensus by scientific observers at the time was that this award was long overdue, but the phage group's work was so revolutionary when it was first performed that its significance was fully appreciated only in the light of later work.

In 1972 Luria was asked by the president of MIT to create a Center for Cancer Research, and he recruited a stellar group of scientists, thus putting the center on a firm footing before his retirement in 1985. In 1984 Luria published his autobiography, A Slot Machine, A Broken Test Tube, the last of a series of books he wrote before his death from a heart attack in 1991 at his home in Lexington, Massachusetts. These include a textbook on viruses written in the 1950s and two books on biology written in the 1970s. One of these, Life: The Unfinished Experiment (1973) received the National Book Award in 1974.

A friendly and witty man, Luria had other interests besides science. He studied sculpture while on sabbatical in France in the 1960s and continued to create works for several years. Toward the end of his life he taught a world literatures course at MIT. Throughout his career Luria was interested in liberal political causes. He was active in the peace movement, being a critic of the Vietnam War and of U.S. defense spending.

Luria is considered one of the most influential molecular biologists of the twentieth century because of the breadth of his interests and the quality of his discoveries. He opened up several new fields, including phage research, as well as the study of mutations at the molecular level, the repair of radiation damage, and the enzymes needed for genetic engineering. His Nobel Prize capped a career that put him at the center of the most important discoveries in mid-century biochemistry.

Luria's papers are located at the American Philosophical Library in Philadelphia, Pennsylvania. Biographies of Luria include his autobiography, A Slot Machine, A Broken Test Tube (1984). See also "Salvador Edward Luria," in Modern Scientists and Engineers (1980) and James Watson, "Memoirs: Salvador E. Luria," in Proceedings of the American Philosophical Society (1999). Obituaries are in the New York Times (7 Feb. 1991) and the Washington Post (8 Feb. 1991).

Maura C. Flannery