Delbrück's brother Justus, a lawyer, as well as his sisterEmmi Bonhoeffer were active along with his brothers-in-lawKlaus Bonhoeffer andDietrich Bonhoeffer inresistance to Nazism. Found guilty by thePeople's Court for roles in theJuly 20, 1944 plot to assassinate Hitler, Dietrich and Klaus were executed in 1945 by theRSHA. Justus died in Soviet custody that same year. His son, Tobias Delbruck is a professor at the Institute of Neuroinformatics at the University of Zurich and ETH Zurich.[7] Professor Tobias Delbruck is also one of the pioneers in the domain of event cameras,[8] now increasingly being deployed in dynamic vision systems.
Delbrück's workplace in Berlin: Kaiser Wilhelm Institute for Chemistry, now theFree University of Berlin.
Delbrück returned to Berlin in 1932 as an assistant toLise Meitner, who was collaborating withOtto Hahn on irradiation ofuranium withneutrons. Delbrück wrote a few papers, including one in 1933 ongamma rays' scattering by aCoulomb field's polarization of a vacuum. Though theoretically tenable, his conclusion was misplaced, whereasHans Bethe some 20 years later confirmed the phenomenon and named it "Delbrück scattering".[10]
In 1935, Delbrück published a collaboration withNikolay Timofeev-Ressovsky andKarl Zimmer the major work,Über die Natur der Genmutation und der Genstruktur. It was considered to be a major advance in understanding the nature of gene mutation and gene structure.[11] The work was a keystone in the formation of molecular genetics.[12] It was also an inspirational starting point for Erwin Schrödinger's thinking, a course of lectures in 1943, and the eventual writing of the bookWhat Is Life? The Physical Aspect of the Living Cell.[13]
Drawing of a plaque in Buttrick Hall, Vanderbilt University commemorating the work of Max Delbrück.[18]
Although Delbrück'sRockefeller Foundation fellowship expired in 1939, the Foundation matched him up withVanderbilt University inNashville, Tennessee, where from 1940 to 1947 he taughtphysics, yet had his laboratory in the biology department.[19] In 1941, Delbrück metSalvador Luria ofIndiana University who began visiting Vanderbilt.[19] In 1942,Delbrück and Luria published onbacterial resistance tovirus infection mediated by randommutation.[19]Alfred Hershey ofWashington University in St. Louis began visiting in 1943.[19] The Luria–Delbrück experiment, also called the Fluctuation Test, demonstrated that Darwin's theory of natural selection acting on random mutations applies to bacteria as well as to more complex organisms. The 1969 Nobel Prize in Physiology or Medicine was awarded to both scientists in part for this work. To put this work in its historical perspective,Lamarck in 1801 first presented his theory of Inheritance of Acquired Characteristics, which stated that if an organism changes during life in order to adapt to its environment (for example stretches its neck to reach for tall trees), those changes are passed on to its offspring. He also said that evolution happens according to a predetermined plan. Darwin published his theory of evolution in his 1859 bookOn the Origin of Species with compelling evidence contradicting Lamarck. Darwin said that evolution is not predetermined but that there are inherent variations in all organisms, and that those variations that confer increased fitness are selected by the environment and passed on to the offspring. In the feud between Lamarck and Darwin, Darwin talked of pre-existing changes, but the nature of these changes was not known and had to await the science of genetics byGregor Mendel's experiments on pea plants published in 1866. Support for Darwin's theory was provided whenThomas Hunt Morgan discovered that a mutated white-eyed fruit fly among red-eyed flies was able to reproduce true white-eyed offspring. The most elegant and convincing support for Darwin's ideas, however, was provided by theLuria-Delbruck experiment,[20][21][22] which showed that mutations conferring resistance of the bacterium E. coli to T1 bacteriophage (virus) existed in the population prior to exposure to T1 and were not induced by adding T1. In other words, mutations are random events that occur whether or not they prove to be useful, while selection (for T1 resistance upon challenge with T1 in this case) provides the direction in evolution by retaining those mutations that are advantageous, discarding those that are harmful (T1 sensitivity in this case). This experiment dealt a blow to Lamarckian inheritance and set the stage for tremendous advances in genetics and molecular biology, launching a tsunami of research that eventually led to the discovery of DNA as the hereditary material and to cracking the genetic code. Of course, by thenAvery, along with McCloud (and earlier, McCarty) was well on the way to showing the genetic capability of DNA.
In 1945, Delbrück, Luria, and Hershey set up a course inbacteriophage genetics atCold Spring Harbor Laboratory onLong Island, New York.[19] ThisPhage Group spurredmolecular biology's early development.[23] Delbrück received the 1969Nobel Prize in Physiology or Medicine, shared with Luria and Hershey "for their discoveries concerning the replication mechanism and the genetic structure of viruses".[3][19][24] The committee also noted that "The honour in the first place goes to Delbrück who transformed bacteriophage research from vague empiricism to an exact science. He analyzed and defined the conditions for precise measurement of the biological effects. Together with Luria he elaborated the quantitative methods and established the statistical criteria for evaluation which made the subsequent penetrating studies possible. Delbrück's and Luria's forte is perhaps mainly theoretical analysis, whereas Hershey above all is an eminently skillful experimenter. The three of them supplement each other well also in these respects." That year, Delbrück andLuria were also awarded byColumbia University theLouisa Gross Horwitz Prize. In late 1947, as Vanderbilt lacked the resources to keep him, Delbrück had returned to Caltech as a professor of biology, and remained there for the rest of his career.[19] Meanwhile, he set upUniversity of Cologne's institute formolecular genetics.
Delbrück helped spurphysical scientists' interest in biology. His inferences on genes' susceptibility to mutation was relied on by physicistErwin Schrödinger in his 1944 bookWhat Is Life?,[27] which conjectured genes were an "aperiodic crystal" storing codescript and influenced crystallographerRosalind Franklin and biologistsFrancis Crick andJames D. Watson in their 1953 identification of cellular DNA's molecular structure as a double helix.[28][29] In 1977, he retired fromCaltech, remaining a Professor of Biology emeritus. He became interested in the behavioral sciences and spent some unfruitful effort on mold behavior in the 1960s.
Max Delbrück died, at age 74, on the evening of Monday, March 9, 1981, atHuntington Memorial Hospital inPasadena, California. On August 26 to 27, 2006—the year Delbrück would have turned 100—family and friends gathered at Cold Spring Harbor Laboratory to reminisce on his life and work.[30] Although Delbrück held some anti-reductionist views; he conjectured that ultimately a paradox—akin perhaps to thewaveparticle duality ofphysics—would be revealed about life. His view however, was later refuted upon the discovery of thedouble helix structure of DNA.[31]
^ab"Max Delbrück".Encyclopædia Britannica. Encyclopædia Britannica, Inc.Archived from the original on December 26, 2018. RetrievedJune 25, 2013.A refugee from Nazi Germany, Delbrück went to the United States in 1937, serving as a faculty member of the California Institute of Technology (1937–39; 1947–81) and of Vanderbilt University (1940–47). He became a U.S. citizen in 1945.
^Ton van Helvoort (1992). "The controversy between John H. Northrop and Max Delbrück on the formation of bacteriophage: Bacterial synthesis or autonomous multiplication?".Annals of Science.49 (6):545–575.doi:10.1080/00033799200200451.PMID11616207.
^Lily E. Kay (1985). "Conceptual models and analytical tools: The biology of physicist Max Delbrück".Journal of the History of Biology.18 (2):207–246.doi:10.1007/BF00120110.PMID11611706.S2CID13630670.
^Stefanie Tapke."Max Delbrück – Biographical".Biographical article. Nobel Media.Archived from the original on June 12, 2018. RetrievedSeptember 13, 2013.
^Ellis E.L. "Bacteriophage: One-step growth curve" in Phage and the Origins of Molecular Biology (2007) Edited by John Cairns, Gunther S. Stent, and James D. Watson, Cold Spring Harbor Laboratory of Quantitative Biology, Cold Spring Harbor, Long Island, New YorkISBN978-0-87969-800-3
^Luria SE "Mutations of bacteria and bacteriophage" in Phage and the Origins of Molecular Biology (2007) Edited by John Cairns, Gunther S. Stent, and James D. Watson, Cold Spring Harbor Laboratory of Quantitative Biology, Cold Spring Harbor, Long Island, New York, pgs. 173-179.ISBN978-0-87969-800-3
^Luria SE. A Slot Machine, a Broken Test Tube. An Autobiography. Harper and Row, New York, 1984. Alfred P. Sloan Foundation Series
^M. P. Murphy and L. A. J. O'Neill (1997).What Is Life? the Next Fifty Years: Speculations on the Future of Biology. Cambridge University Press.p 2.ISBN0-521-59939-3
Letter from Jim Watson – Delbrück was instrumental in getting fellowship support for Watson so that he could stay in Cambridge, play tennis, and discover the rules of nucleotide base pairing in DNA. This is a letter from Watson to Delbrück that describes the discovery.
Interview with Max Delbrück Oral History Project, California Institute of Technology Archives, Pasadena, California.
