Tag Archives: Jacques Monod

The Life and Legacy of George Klein: Cancer Virus Pioneer and Witness to the Holocaust

George Klein, professor emeritus of tumor biology at the Karolinska Institute in Stockholm, where he worked with his wife Eva from the very beginning, passed away on December 10, 2016, at the age of 91. Klein was best known for discovering that Epstein-Barr virus (EBV)—the herpesvirus now known to cause infectious mononucleosis—causes two human cancers, Burkitt’s lymphoma and nasopharyngeal carcinoma. Moreover, Klein discovered that EBV triggers Burkitt’s lymphoma by facilitating a chromosomal translocation of the cellular c-myc oncogene, resulting in its constitutive expression. Klein also played pioneering roles in developing the concept of tumor-suppressor genes, and in opening the field of tumor immunology. Klein’s key discoveries are summarized below. But, first, Klein, like several other protagonists in these tales, was profoundly affected by events of the Second World War, and by the early days of the Cold War that followed.

From an announcement for a 2015 symposium at the Karolinska Institute, honoring George and Eva on the occasion of their 90th birthdays

George Klein’s Jewish family moved from Eastern Slovakia to Budapest in 1930. Nineteen-year-old George was working as an assistant secretary to the Jewish Council in Budapest when Nazi Germany began its occupation of Hungary in March 1944. Because George had been working for the Jewish Council, in April 1944 he chanced that to see the Vrba-Wetzler Report, known at the time as the “Auschwitz Report.” It was written by, and was secretly transmitted to the Jewish Council by Rudolf Vrba and Alfred Wetzler, two escapees from Auschwitz. It described firsthand the fate of Jews arriving at Auschwitz, and was meant to warn Hungary’s Jews, so that they might hide from, or rebel against their Nazi oppressors.

The Auschwitz report was not publicized in Hungary for reasons explained below. However, George’s supervisor at the Jewish Council gave him permission to tell his relatives and friends of what the report revealed. But they, like most Hungarian Jews, could not believe that such atrocities could actually be taking place. [During May, June, and July 1944, 437,000 Hungarian Jews were deported to Auschwitz; to be “resettled” according to the Nazis. But, in fact, most were murdered in the gas chambers.]

Klein was arrested and pressed into forced labor by the Nazis. Afterwards, since he knew the contents of the Auschwitz Report, he fled when he was about to be ordered to board one of the deportation trains to Auschwitz. Having escaped from almost certain death, he lived underground until January 1945, when the Russian Army liberated Budapest.

Forty-three years later, Klein was watching, Shoa, the monumental (nine-hour-long) French documentary film about the holocaust. Watching the movie, Klein chanced to see a man named Vrba (one of the six principal holocaust witnesses in the film) describe his experiences as a prisoner in Auschwitz. The events that Vrba recounted horrified Klein.

Later in the film, as Vrba described his escape from Auschwitz, Klein suddenly realized, “the report I had been given to read under a promise of secrecy in Budapest in May 1944—at the age of nineteen and at a time when deportations from the Hungarian countryside were at their peak—was identical to the Auschwitz Report of Vrba and Wetzler (1).”

Next in this remarkable tale, Klein decided to try to find Vrba, to “tell him of what enormous help his report had been to me. If I had not known what was awaiting me at the other end of the train trip, I would never have dared to risk an escape. It was not difficult to find Vrba, for it turned out that we were scientific colleagues. He is a professor of neuropharmacology in Vancouver, and I am now (in the Spring of 1987) sitting in a comfortable armchair in the faculty club at a Canadian university, talking with someone who, at first glance, seems quite ordinary. He impresses me as being relaxed and jovial. By now I have also read his book (Escape from Auschwitz, 1964), and I am aware that he has survived more death sentences than anyone else I have ever met (1).”

Vrba (1924–2006), was indeed a professor of pharmacology at the University of British Columbia; a position he held from 1976 until the early 1990s. Note that he and Wetzler were the first prisoners ever to escape from Auschwitz. Vrba’s real name was Walter Rosenberg. Rudolf Vrba was the nom de guerre he used after joining the resistance in his native Czechoslovakia. Afterwards, he made the change legal.

The horrors of the holocaust remained an obsession for Klein, although he was uncertain as to why that was so. “Was it to honor my murdered family, my murdered classmates? Or was it rather to steel myself against the darkest side of our human heritage?” In any case, Auschwitz and the holocaust were the main topics of conversation when Klein met with Vrba.

Vrba took Budapest’s Jewish Council to task for not widely broadcasting the warnings in the Auschwitz Report. He, and others, have alleged that Dr. Kastner, a well-known Zionist leader in Budapest, decided to keep the Report secret, in return for a promise from the Germans to allow sixteen-hundred people, as selected by Kastner, to safely emigrate from Hungary. Klein retorted that he knew Kastner from his work for the Jewish Council, and considered him to be a hero, because he had rescued many, while others tried to rescue only themselves or their own families. [In 1957, Kastner was murdered in Israel by a young man whose family was exterminated by the Nazis. Kastner remains a controversial figure to this day.]

Klein and Vrba next discussed whether dissemination of the Auschwitz Report might have caused Budapest’s Jews to revolt against the Nazi program of annihilation.  Klein argued that of the dozen or so people that he warned, no one believed him. Vrba countered, “You were a mere boy. Why would anyone believe what you were saying? The Jews would certainly have believed their responsible leaders (1).” Nonetheless, Vrba conceded that even the prisoners at Auschwitz were in denial of what they could see with their own eyes: “…prisoners, who knew full well that no one ever returned from the gas chambers, repressed such knowledge as they themselves lined up for execution in front of the chamber doors.”

Klein asked Vrba how he is able to live and function in Vancouver, a pleasant and friendly place, where no one has the slightest concept of what he endured: “…you must go back constantly to those days. You are called in as a witness at trials of old Nazis or their followers, people who claim that the holocaust never happened. You try to describe something that cannot be described in any human language, you try to explain the incomprehensible, you want people to listen to something they do not want to hear (1).” Vrba, in fact, never did reveal his Auschwitz experience to his colleagues. Vrba explained: “What would have been the use? No one who has not experienced it can understand.” Their conversation went on for almost ten hours. Afterwards, they parted like old friends, despite any differences in their views.

In the Fall of that year, Klein was reunited with Vrba in Paris, together with another newfound friend, German scientist Benno Muller-Hill. In 1966, Muller-Hill was a graduate student in Walter Gilbert’s Harvard laboratory, when he purified the lac repressor; the first genetic control protein to be isolated. Muller-Hill then began a second career lecturing and writing about the role of Nazi doctors and scientists in the holocaust. Klein met Müller-Hill for the first time at a meeting at the Institute for Genetics in Cologne, and the two immediately developed a close friendship.

Muller-Hill was in Paris to visit colleagues at the Pasteur Institute, as well as to meet Vrba. Klein was visiting Paris after attending a scientific meeting in Lyon. Vrba was in Paris at the invitation from the French radio service to refute claims of the ultra-right French leader, Jean Marie Le Pen, that the Nazi gas chambers never existed, and that if the Nazis indeed had any intent to annihilate the Jews, it was merely one of many episodes of the war. [Marine Le Pen, currently a leader of France’s ultra-right National Front, and a candidate for the presidency of France, is Jean Marie’s daughter. She was recently taken to task for denying that French officials and police were complicit in the Nazi roundup of more than 13,000 French Jews in July 1942 (they were later deported to Auschwitz). Le Pen also calls for the deportation of all immigrants from France; a stance that mainly targets Muslims.]

Klein and his two companions ambled about Paris on a beautiful Fall afternoon. They strolled around the Luxembourg Gardens, then continued along the banks of the Seine, turned toward the Latin Quarter, and then stood before the façade of Notre Dame. Yet their minds were elsewhere. “Vrba suggested that we visit the holocaust memorial behind Notre Dame…That walk of only a few minutes took us from the noisy tourist crowd to the silence of the museum’s rooms, where you feel alone and isolated among the symbolic chains and barbed wire. A faint glow of sunlight came in through the narrow openings in the wall. We were surrounded by the voices of the victims…We were all completely speechless. Even Vrba’s macabre sense of humor and his sharp sarcasm had fallen silent for the moment (1).”

After they exited from the memorial, they sat down in a small bistro, where Klein asked his two companions whether German scientists and doctors were actual architects of the holocaust or, instead, merely passive followers. “Benno had concluded from his exhaustive documentation that, contrary to what many wanted so desperately to believe, the ‘euthanasia programs’…and the horrible human experiments… could not be ascribed to a small minority of madmen, opportunists, or charlatans. On the contrary, they had been carried out by quite ordinary and in some instances, eminent physicians and scientists… He (Verba) thought … that would not explain why so many apparently ordinary people took part in the murders without showing any signs of remorse, or how the annihilation program could have been carried out with such efficiency… The discussions between Benno and Vrba continued for several hours (1).”

The day became even more notable later, since Klein had arranged for the threesome to have dinner that evening with Francois Jacob. After a glass of sherry in Jacob’s Latin Quarter apartment, the foursome went to a small restaurant around the corner.

Francois Jacob, and fellow Pasteur Institute scientist Jacques Monod, were awarded Nobel Prizes for their work together on the regulation of lactose metabolism in E. coli (2). More apropos the current episode, Jacob and Monod each received France’s highest military honors for his service during the Second World War—Jacob for his heroism serving with the Free French forces, and Monod for his heroism in the Resistance (2). Yet Jacob’s harrowing escape from Nazi-occupied France at 19-years in age, and his wartime exploits as one of Charles De Gaul’s most highly decorated volunteers, were barely known to his three dinner companions.

At first, Klein was somewhat worried that his friends might not like each other. Jacob often found conversation to be difficult; partly because the thousands of pieces of shrapnel that he carried in his body from the war, made it hard for him to sit comfortably. [Jacob’s wartime wounds prematurely ended his surgical career, and led him to turn to a career in science (2).] But, the get-together didn’t go badly at all.

Conversation eventually turned to the issue of holocaust deniers, as well as to those who would put the past completely behind them. As they talked, the incongruity of the scene suddenly struck Klein. They were sitting in a “first-class Parisian restaurant, surrounded by elegant people, having a very nice dinner in the best French tradition.” “…why did the three of us, with Jacob listening, choose to spend that beautiful Saturday in Paris compulsively focusing our attention on the black birds? We were all citizens of free countries, living well in peaceful times. Were we haunted by feelings of guilt toward the dead? Were we afraid that the whole experience would recur if we let go? We knew that the wide and relentless river of history is rarely influenced by knowledge of the past. In no more than one or two generations, archives of extreme horror turn into scraps of faded paper, with no more influence than dried leaves. I suddenly felt that we were like a traveler with a fear of flying, forcing himself to stay awake and keep his seatbelt buckled during the entire flight, obsessed with the idea that the plane would surely crash if he were to fall asleep. But perhaps we had other motives. Perhaps we wanted to feel a solidarity with each other by selecting a more or less taboo subject for our conversation, one avoided by most others. Or did we try to perform a kind of autopsy, using our brains to understand what human minds are capable of at their worst? Have we appointed our brains to serve as the pathologist and the cadaver at the same time?”

The above recounts only a small sampling of Klein’s conversations with Vrba, Muller-Hill, and Jacob, during their day together in Paris. For more, see reference 1.

In January 1945, 19-year-old George Klein emerged from the Budapest cellar where had been hiding during the last weeks of the German occupation. He gazed on the dead soldiers, civilians, and horses that were frozen in the snow, and was struck by the thought that he had survived, despite the likelihood that he would have ended his 19 years in a Nazi gas chamber or a slave labor camp. However, with the city now in Russian hands, George faced a new threat to his freedom; the Russian patrols that were exporting young Hungarians to labor camps in Russia.

Mindful of the danger on the streets, George was yet eager to begin his medical studies. So, he cautiously dodged the Russian patrols as he made his way to Budapest’s medical school, only to find war-torn deserted buildings and dead soldiers there.

Undeterred by the situation in Budapest, George and a friend set out to Szeged, with the hope of attending the medical school there. The journey of 160 miles took the pair five days, by way of a variety of vehicles, including a Russian military truck. In any case, they were admitted to the Szeged university on the same day that they arrived. And while the school was a shadow of its former self, with all the professors having fled to the West, to George, it was a “previously forbidden paradise (3).”

George spent two years in Szeged, and then returned to Budapest when the University reopened there. Back in Budapest, George fell “desperately” in love with Eva Fisher, a fellow medical student. [George describes their whirlwind romance in reference 3.] George now faced a dilemma. Before he met Eva, he finalized plans to visit Stockholm (under the sponsorship of the Jewish Student Club there). But going to Stockholm would mean leaving Eva behind, under conditions in which travel back into Hungary could be risky. Nonetheless, George went to Stockholm, with Eva believing she would never see him again. Yet the trip would be a defining experience for George and, eventually, would be important for Eva too. In Stockholm, George would learn of, and be riveted by the research of renowned cell biologist Torbjörn Caspersson, at Stockholm’s Karolinska Institute.

Caspersson’s research so enthralled George that he diligently pressed Caspersson for a junior research assistantship in his laboratory. But once George had been accepted by Caspersson, he viewed his situation with a “mixture of ecstatic happiness and enormous anxiety.” “I knew virtually nothing…I was halfway through my medical studies…I was desperately in love with a girl whom I had only known during a summer vacation of eight days and who was on the other side of an increasingly forbidding political barrier (3).”

Despite these misgivings, George knew that his future lay in Sweden, rather than Hungary. He had been accepted into Caspersson’s laboratory, and Hungary was falling increasingly under totalitarian Soviet domination. But Eva was still in communist Hungary. So, George risked returning there with one goal; to marry Eva, and then to leave Hungary for good. “The reunion with Eva confirmed what we both already knew: we wanted to live and work together (3).”

But George and Eva didn’t have the necessary documents to get married, nor did Eva have a passport to leave Hungry. Moreover, communist bureaucrats made it increasingly difficult to obtain these documents. In some instances, up to six weeks might be needed. However, George and Eva were daring and resourceful. When told by a police officer that it would take at least three weeks to obtain a marriage license, George suddenly acted on impulse: “I had always heard others tell of such things but I myself had neither seen nor done it. I pulled a fairly modest bill out of my pocket and put it in the policeman’s hand. ‘Pardon me, how much time was it you said?’ ‘I’ll go get it at once,’ he answered (3).”

With similar persistence and ingenuity, George and Eva obtained all their necessary documents, and they were married that very day! One document, a certificate asserting that neither George nor Eva had a venereal disease, would normally require a three-week lab test. But they beseeched an older colleague, now a doctor at a children’s hospital, to write the certificate for them. Their colleague did so, on his Children’s Hospital stationary. George and Eva then went to the prefecture to be married, only to find a disagreeable marriage official, who was determined to leave work for the day. But, when the official leafed through their papers, and saw the venereal disease certificate written on Children’s Hospital stationary: “He laughed until tears ran down his cheeks. This was the funniest thing he had seen during his whole time in service.” He then gladly married the couple.

As the Iron Curtain descended about Hungary, George and Eva left for Sweden, where they would now continue their medical studies. What’s more, Eva joined George in Caspersson’s laboratory at the Karolinska Institute. The couple would work together at the Karolinska until George’s death at the age of 91. [Eva was born to Jewish parents in Budapest in 1925. In 1944 and 1945, she and several members of her family hid from the Nazis at the Histology Institute of the University of Budapest. Encouraged by Caspersson, Eva had an independent research career, while also collaborating with George. She is best known for discovering natural killer cells, and for generating the Burkitt’s lymphoma cell lines, which she and George studied together (see below).]

George and Eva, at the Karolinska Institute, 1979

We conclude with a brief review of some of George Klein’s contributions to virology and to cancer research.

Tumor immunology: In 1960, George and Eva used methylcholanthrene to induce tumors in mice. Next, they surgically removed the tumors, killed them with irradiation, and inoculated them back into genetically compatible mice. Next, they challenged these mice with cells from a variety of different tumors, and showed that the immune systems of the inoculated mice rejected only those cancer cells that came from the original tumor. Thus, there are tumor-specific antigens that can be recognized by the immune system. See Aside 1.

[Aside 1: Importantly, the tumor resistance seen in these experiments did not arise spontaneously in the original tumor-bearing animals. Instead, it developed in the test mice, in response to sensitization with killed tumor cells. Thus, these experiments per se do not point towards an immune mechanism of tumor surveillance. Nonetheless, harnessing such a mechanism is currently a promising means of cancer therapy, and was a major theme in Klein’s thinking.]

The following year, Klein’s group showed that polyoma virus-induced tumors share a common antigen. Importantly, polyoma virus-induced tumors, and polyoma virus-transformed cells, were rejected irrespective of whether they released virus. Thus, antiviral immunity as such was neither necessary nor sufficient for tumor rejection. This was the first demonstration that tumors caused by a virus might share a common antigen. The Kleins, and others, later found similar “group-specific” transplantation antigens on other virus-induced tumors, including retrovirus-induced lymphomas.

Burkitt’s lymphoma: “Sometime in the mid-1960s, Eva suggested that we should use our experi­ence on virus-induced murine lymphomas to examine a human lymphoma with a presumptive viral etiology. Could we detect group specific antibody responses that might be helpful in tracing a virus? Burkitt’s lymphoma (BL) was the obvious choice (3).” [Burkitt’s lymphoma, originally described by Dennis Burkitt in 1958, is a malignant B-cell lymphoma that is most prevalent in tropical Africa and New Guinea. It is the most common childhood cancer in equatorial Africa. Burkitt first proposed that the lymphoma might have a viral etiology, since its geographic distribution is like that of yellow fever, which is caused by a flavivirus. In 1964, Tony Epstein and Yvonne Barr, by means of electron microscopy, discovered a virus in cells which they cultured from BL tissue, thereby giving credence to Burkitt’s premise.]

Klein’s group identified a membrane antigen (MA) that was expressed in some BL-derived cell cultures. Werner and Gertrude Henle had previously discovered that the MA antigen is a structural protein from a newly discovered herpesvirus—the virus that Epstein and Barr first saw in 1964. Klein decided to call that virus the Epstein Barr virus (EBV). The MA antigen is now known to be one of the EBV envelope glycoproteins. Klein and collaborators later identified complement receptor type 2 (CR2), also known as the complement C3d receptor, as the cell surface attachment protein for the viral MA glycoprotein. CR2 receptors on B cells play a role in enabling the complement system to activate B cells.

By 1970, Klein’s group, in collaboration with Harald zur Hausen, found that the subset of BL-derived cell lines that express MA are, in fact, those that produce EBV. However, more than 90% of the BL cell lines, and all nasopharyngeal carcinomas, were found to contain multiple EBV genomes per cell, irrespective of whether they produced virus. Thus, only a subset of BL and nasopharyngeal carcinoma cells that harbor EBV genomes, actually produce the virus. During this time, the Henles discovered that EBV is the cause of infectious mononucleosis, and that EBV could immortalize normal B cells in culture.

Oncogene activation by chromosomal translocation: A sero-epidemiological study, begun in Uganda in 1971 by Geser and de-The, showed that children with a high EBV load are more likely to develop BL than are children with a low EBV load. Thus, the presence of EBV genomes in a B cell increases the likelihood of it turning into a BL. “But this is still not a satisfactory explanation; some essential element is obviously missing (3).”

What then is the missing event that gives rise to BL? A 1972 study by Manolov and Manolova, Bulgarian scientists working with the Kleins, found that a particular chromosomal marker, 14q+, was present in about 80% of BL tumors. After the Manolovs returned to Bulgaria, the Kleins, in collaboration with Lore Zech, used the chromosomal banding technique recently developed by Caspersson and Zech to examine the BL-cell chromosomes more precisely. They showed that the 14q+ marker was derived from chromosome 8, which broke at the same site (8q24) and underwent a reciprocal translocation with the short arm of either chromosome 2 or chromosome 22. All BLs carried one of the translocations.

Meanwhile, another research group found that carcinogen-induced mouse plasmacytomas are associated with an almost homologous chromosomal translocation. Thus, a common mechanism seemed to underlie two distinct types of tumors, in two distinct species. In each instance, a putative oncogene was translocated to an immunoglobulin locus, which might then have caused the oncogene to be constitutive expressed. A somewhat similar mechanism was reported earlier for the induction of bursal lymphomas in chickens by the avian leukosis virus (ALV) . In that instance, the cellular c-myc gene came under the control of the ALV provirus promotor. What’s more, Michael Cole’s group identified the transposed gene in BL, and in the mouse plasmacytomas, as c-myc. It is not yet clear how EBV infection promotes the chromosomal translocation.

Tumor suppressor genes: In the early 1970s, Klein, and collaborator Henry Harris, played a pioneering role in developing the concept of tumor suppressor genes. They found that when highly malignant mouse cells are fused with normal mouse cells, the hybrid cells are non-malignant when inoculated into genetically compatible mice. That is, tumorgenicity is suppressed by fusion with normal cells. However, tumorgenicity reappears after some apparently important chromosomes, contributed by the normal cell, are lost from the hybrid cells.


  1. George Klein. Pieta, MIT Press, 1992.
  1. The Converging Lives of Jacques Monod, Francois Jacob, Andre Lwoff, and Albert Camus in Wartime France, Posted on the blog March 27, 2017.
  1. George Klein and Eva Klein. 1989. How One Thing Led to Another, Annual Review of Immunology, 7:1-33.

The Converging Lives of Jacques Monod, Francois Jacob, Andre Lwoff, and Albert Camus in Wartime France

In the 1950s and 1960s, two French biologists at the Pasteur Institute, Francois Jacob and Jacques Monod, explained how genes are regulated in bacteria. Their studies of the “lac operon” of E. coli indeed opened up the field of gene regulation, and were a key development in the new science of molecular biology. Their experimental findings also implied the existence of an unstable intermediate between genes and protein synthesis, which eventually led to Jacob’s discovery, in collaboration with Sydney Brenner and Matt Meselson, of messenger RNA (1).

Jacob and Monod shared in the 1965 Nobel Prize for physiology or medicine for their breakthrough studies on gene regulation. Fellow Pasteur Institute scientist, Andre Lwoff, received a share of the award for his pioneering studies on the nature of lysogeny (i.e., how a bacteriophage’s genome can be incorporated into the genome of a host bacteria, and remain latent until being activated by an inducing factor).

In 2013, evolutionary biologist Sean B. Carroll published a book—Brave Genius: A Scientist, a Philosopher, and their Daring Adventures from the French Resistance to the Nobel Prize—that relates how wartime circumstances brought together Jacques Monod and his scientific colleagues Francois Jacob and Andre Lwoff (2). But while much of that story is already known (3), Carroll also tells us of the little known, but remarkable coming together of Monod and philosopher/writer Albert Camus, one of the intellectual giants of the 20th century. Coming from very different intellectual backgrounds, Monod and Camus forged a deep friendship, united in their opposition to tyranny and oppression. Carroll’s book was the inspiration for this post.

When Albert Camus learned that he had won the Nobel Prize for Literature in October 1957, he wrote to a few well-wishers, including an old friend in Paris:

My dear Monod,

      I have put aside for a while the noise of these recent times in order to thank you from the bottom of my heart for your warm letter. The unexpected prize has left me with more doubt than certainty. At least I have friendship to help me face it. I, who feel solidarity with many men, feel friendship with only a few. You are one of these, my dear Monod, with a constancy and sincerity that I must tell you at least once. Our work, our busy lives separate us, but we are reunited again, in one same adventure. That does not prevent us to reunite, from time to time, at least for a drink of friendship! See you soon and fraternally yours.

                                                                                                                                             Albert Camus

Camus appears somewhat downcast in his note to Monod. At 43-years-in-age, he was the second youngest writer ever to receive the Nobel Prize for literature (Rudyard Kipling at 42 was the youngest), and he was worried that the ballyhoo surrounding the award might distract him from his writing. And, he was concerned that the prize might stir up additional contempt from critics of his writing, as well as from his leftist colleagues who opposed his condemnation of Soviet communism.

But, why did philosopher/writer Camus—an intimate of some of the greatest writers and artists of the mid-twentieth century, including Sartre and Picasso—write to scientist Monod, and acknowledge the special importance he placed on their friendship? Likewise, why did he assert: “I have known one true genius, Jacques Monod.” And, what is the same adventure that Camus refers to?

A brief background to our tale is as follows. In March 1939, Hitler took control of Czechoslovakia. Next, on September 1, Germany invaded Poland. On September 2nd, Poland’s allies, Britain and France, issued an ultimatum to Germany: withdraw or face war. On September 3rd, the ultimatum expired, Britain and France declared war on Germany, and the Second World War was underway; sort of. Although Germany went on to conquer Poland in a mere eight days, several months passed without further action. Then, in May 1940, Nazi Germany invaded and overran France in just six weeks. Marshall Pétain surrendered to the Germans, the French Forces were disbanded, the pro-Nazi Vichy government was put in place under former prime minister Pierre Laval and the 84-year-old Pétain, and the Nazi occupation of the defeated French nation began.

A few months before the Nazis invaded France, thirty-year old Jacques Monod was a doctoral student in zoology at the Sorbonne. [A polymath, he also founded a Bach choral group, and was an accomplished cellist, and seriously considered a career in music (4).]  But as war with Germany loomed, Monod enlisted in the army—in the communication engineers—where he thought he might use his scientific talents if war were to break out. Consequently, Monod was serving on the front lines when the Germans invaded. France suffered the most colossal military disaster in its history, and Monod returned to his studies in Paris.

Life in France grew progressively harsher under the Nazis; beginning with subjugation, and followed by deportations, enslavement, and mass murder. Early on, Monod joined one of the first units of the French Resistance; a group of ethnologists and anthropologists at the Musée de l’Homme (Museum of Man).

One of Monod’s duties for the Musée de l’Homme group was to distribute its newspaper, at night. This seemingly simple task was extremely dangerous since capture could mean deportation to a concentration camp or execution. Monod, in fact, had several close escapes. On one occasion, the Gestapo raided his laboratory at the Sorbonne. Fortunately, since they were fearful of the viruses and radioactive isotopes in the lab, they didn’t search it as thoroughly as they might have. Otherwise, they might have found sensitive documents that Monod would hide inside the leg of a mounted giraffe outside his office. In any case, the Germans soon routed the short-lived Musée de l’Homme group

Monod’s wife, Odette, was the granddaughter of Zadoc Kahn, the former chief rabbi of France. Since the Vichy government soon began enacting Nazi policies, including anti-Jewish laws, and because of homegrown French anti-Semitism, Odette sought refuge for herself, and for her and Jacque’s twin sons (born in August 1939, four weeks before the war broke out), under assumed names, in a village outside of Paris. Meanwhile, Jacques had to register with the Vichy authorities as the spouse of a Jewish person.

With Odette and the children concealed, Monod joined the most militant unit in the Resistance; the Communist-led Franc-Tireurs (Free Shooters) group. Monod was not then a Communist Party member. Nonetheless, he joined the Franc-Tireurs since they actually were fighting the Germans—assassinating German officers in the streets and carrying out sabotage. One of his missions for the Franc-Tireurs took him to Geneva—through the Alps to avoid arrest—to request money for arms from the United States Office of Strategic Services; the precursor of the present Central Intelligence Agency.

By this time, Monod had gone completely underground. He wore a disguise during the day, slept in safe houses at night, and stayed away from his laboratory at the Sorbonne. But then, Andre Lwoff, the head of microbial physiology at the Pasteur Institute, offered Monod a refuge and a place to work in his laboratory at the Pasteur Institute. Monod then led a double-life. By day, as Monod, he worked on his experiments at the Pasteur Institute. At night, he carried out his duties for the Franc-Tireurs, as “Marchal” (from a character in a novel by Stendhal), and as  commander “Malivert.” [Lwoff too had been active in the Resistance, gathering intelligence for the Allies, while also hiding downed American airmen in his apartment.]

Jacques Monod’s identity card for the French Forces of the Interior (FFI), in his nom de guerre ‘Malivert.’

Monod was resolutely committed to the Resistance, while also maintaining a productive research program. At the Pasteur Institute, he and his student, Alice Audureau, made key discoveries that would lead to the later breakthroughs he would make with Jacob. [For instance, Monod and Audureau discovered mutations in E. coli genes that caused the induction of lactose metabolism; a finding that would have important implications concerning gene action and regulation.] Moreover, he was devoted to Odette and their twin sons, and managed to make frequent clandestine visits to see them.

Monod took on increasing responsibilities in the Franc-Tireurs, as more members of the group were discovered and executed by the Germans. In fact, by the time of the allied invasion of Normandy in June 1944, Monod, had become chief of staff of the operations bureau for the National Resistance Organization; a position from which his three predecessors had disappeared (4). As such, Monod prepared battle plans for the allied surge to Paris. He also arranged parachute drops of weapons, railroad bombings, and mail interceptions.

Interestingly, Monod also recruited to the Resistance renowned French chemist, John Frédéric Joliot-Curie (Aside 1), who devised a unique recipe for Molotov cocktails, which were the Resistance’s principal weapon against German tanks. In addition, Monod organized the general strike that facilitated the liberation of Paris. Then, after the liberation of Paris, he became an officer in the Free French Forces, and a member of General de Lattre de Tassigny’s general staff.

[Aside 1: John Frederick Joliet was working as an assistant to Marie Curie, when he married Marie’s daughter, Irene. Afterwards, both John Frederick and Irene changed their surnames to Joliot-Curie. In 1935, the couple was awarded the Nobel Prize in Chemistry for their seminal research on radioactivity. John Frederick then worked at the Collège de France on controlled chain reactions. His work on that was cited by Albert Einstein in his famous 1939 letter to President Franklin Roosevelt, warning Roosevelt of the possibility of a nuclear weapon: “In the course of the last four months it has been made probable through the work of Joliot in France as well as Fermi and Szilard in America—that it may be possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future…This new phenomenon would also lead to the construction of bombs…” The Nazi invasion ended Joliet-Curie’s nuclear research. Nevertheless, he managed to smuggle his research notes out of France to England.]

Francois Jacob, a Jewish, nineteen-year old 2nd-year medical student, was planning on a career in surgery when the German occupation of France began in the Spring of 1940. Resolved to carry on the fight against Hitler, Jacob left medical school and boarded one of the last boats for England. In London, he was one of the first of the French to join Charles de Gaulle’s Free French Forces. He wanted to enroll in a combat unit, but, despite his incomplete medical training, he was commissioned as a medical doctor, and then served as a medical officer in North Africa. His surgical career was prematurely cut short in August 1944, when he was severely wounded at Normandy; by a bomb dropped from a German Stuka dive bomber. At the time, he was tending to a dying officer.

For their wartime service, Jacob and Monod were each awarded France’s highest honors for valor. Jacob was awarded the Cross of Liberation, as well as the Légion d’Honneur and the Croix de Guerre. Monod likewise received the Légion d’Honneur and the Croix de Guerre, as well as the American Bronze Star.

Unable to practice surgery after the war because of his wartime wounds, Jacob eventually turned to a career in science. He was accepted at the Pasteur Institute, where he beseeched Lwoff (Monod’s host at the Pasteur Institute) to serve as his mentor. Lwoff rebuffed Jacob several times, but finally agreed to take the young doctor under his wing. Then, in the cramped quarters of Lwoff’s laboratory at the Pasteur, Jacob and Lwoff’s student, Elie Wollman, began a fruitful collaboration that produced key insights into bacterial conjugation and the regulation of lysogeny (Aside 2). After that, Jacob and Monod forged their extraordinary collaboration that would lead to their Nobel Prizes. Note that Jacob’s earlier work with Wollman, on lysogenic induction, would provide the underpinning for his later work on gene regulation with Monod (3).

[Aside 2: Elie Wollman, born in 1917, was Jewish. In 1940, he escaped from the Nazis in Paris and then worked underground in the Resistance as a physician. His parents, Eugene and Elizabeth Wollman, were Pasteur Institute scientists who were seized by the Nazis in 1943 and sent to Auschwitz. They were never heard from again (3).]

In December of 1939, our other main protagonist, twenty-six-year-old Albert Camus, was an unknown, aspiring writer, working as a reporter and editor for a newly founded left-wing newspaper, Alger Republican, in his native Algeria; which was then under French control. Camus was completely opposed to the war, which he saw as “another unnecessary, avoidable, disastrous, absurd chapter of history that would consume the lives of those who did not make it or wish for it.” His antiwar editorials in the Alger Republican outraged French government officials who were calling for unity against Germany. The government finally shut down the newspaper, leaving Camus unemployed. So, Camus returned to France, where the prospects for employment were now better because wartime mobilizations had left many businesses shorthanded. See Aside 3.

[Aside 3: Camus started writing The Stranger while in Algeria, basing it on people and places he knew there. His purpose in The Stranger was to express how one might react to his philosophical notion of the “absurd”—the disconnect between our desire for a rational existence, and the actual world, which appears confused and irrational—in the form of a novel. Meursault, the narrator, and principle character in The Stranger, shows no grief over his mother’s death, no remorse over having committed an unintended murder, and no belief or interest in god. Even while Meursault was awaiting the guillotine, he was reconciled to “the tender indifference of the world.” Meursault’s honesty in describing his feelings makes him a ‘stranger’ in the setting of the novel, and seals his fate.]

Camus was not called up for military service when he returned to France, because he had contracted tuberculosis in Algeria, when he was 17 (Aside 4). Nonetheless, he twice attempted to enlist—the second time when the French Army was on the verge of surrender to the Nazis—to express his solidarity with those who were being drafted. In any case, the military rejected him each time because of his tuberculosis. So, he managed to get a job in Paris as a layout designer for the newspaper Paris-Soir.

[Aside 4: In the pre-antibiotic era, tuberculosis was often fatal, and the 17-year-old Camus indeed had a close brush with death. That experience had a profound effect on the “precocious philosopher,” who made notes on the question of “how, in the light of the certainty of death, one should live life.”]

Parisians began fleeing from their city when the German invasion began in May of 1940. Then, in June, as the Germans were on the verge of entering Paris, the stream of refugees became a flood, with about 70 percent of the city’s metropolitan population of nearly five million eventually taking flight from the city. All Parisian newspapers stopped publishing. However, Paris-Soir hoped to resume its operations in the south, with a reduced staff. Thus, Camus joined the stream of refugees, driving an automobile (almost all the paper’s regular drivers had been drafted), with a Paris-Soir executive as his passenger. After Camus and his passenger were well on their way, Camus suddenly realized that in the rush to vacate from Paris, he may have left his manuscript for The Stranger behind in his room. “He jumped out of the car and threw open the trunk, and was relieved to find in his valise the complete text of The Stranger.” See Aside 5.

[Aside 5: In 1885, Joseph Meister, at nine-years-of-age, was the first recipient of Louis Pasteur’s rabies vaccine and, as an adult, was caretaker of the Pasteur Institute; a position that he still held at the start of the Nazi occupation in 1940.  In despair over the fall of France, and wrongly believing that German bombs killed his family after he sent them away, he went to his apartment, closed the windows, and turned on the gas in his stove (5, 6).]

Camus went with Paris-Soir to Clermont-Ferrand. There, the paper began to publish again, using printing facilities made available by Pierre Laval, the former premier, and now architect of the Petain Vichy government. But with the paper now under Laval’s control, it began publishing anti-Semitic articles, and other articles in support of the Vichy government. Camus did not write any of these items. In any case, he was let go by Paris-Soir after the draftees of the 1940s were discharged and could return to work. Camus then went back to Algeria, where he completed The Stranger.

In 1942, with The Stranger about to be published in France, Camus suffered a nearly fatal relapse of his tuberculosis. He wanted to return to France for treatment in the Massif Central mountain range, but several months would pass before Algerian authorities gave him permission to do so. Then, upon returning to Paris, he would have a purpose that would totally engage him.

One night, under an assumed name (because of the need for secrecy in the Resistance), Camus stole into the clandestine headquarters of Combat (the journalistic arm and voice of the French Resistance), to implore the staff to take him on since he “had already done a little journalism” and would be happy to help in any way. Like Monod, Camus then led a double-life, carrying out his duties at Combat, as “Bauchard.” At first, he helped to select and edit articles, and prepare the paper’s layout. Then, in 1943 he became the paper’s editor, and wrote stirring editorials, exhorting Frenchmen to act against the German occupiers. By the time The Stranger was published in 1942, his recognition as Camus led to his acceptance into the literary and artistic circle that included Sartre, Simone de Beauvier, and Picasso.

Albert Camus’s false identity card, in the name of Albert Mathé, writer. All of the information on the card — birthdate, place, parents — is false.

Camus was suffering from recurrent bouts of tuberculosis all the while that he was carrying out his work at Combat. Nonetheless, as Camus, he also published his essay, The Myth of Sisyphus, which, like The Stranger, contemplates the experience of the Absurd (see Aside 3, above). And he also wrote The Plague, which depicts a city’s response to an outbreak of bubonic plague; perhaps a metaphor for the Nazi occupation. Remarkably, no one at Combat had an inkling that the man who at first had been editing and arranging pages for them as Bauchard was in fact the now renowned Camus. See Aside 6.

[Aside 6: Among laypeople, Jacques Monod is perhaps best known for his “popular” book, Chance and Necessity, published in 1970, and a bestseller in its day. Monod’s Chance and Necessity, and Camus’ The Myth of Sisyphus, are each relevant here because they point up how Camus influenced Monod’s view of the meaning of life. While Camus took a philosophical approach to that issue, Monod’s assessment was also informed by his knowledge of life’s fundamental molecular mechanisms. With the 1953 discovery by Watson and Crick of the molecular structure of DNA, it was apparent how accidental, random, unpredictable mutations in the sequence of bases in DNA were the source of all biological diversity. Thus, Monod knew that all living forms, including humans, are the products of chance genetic mutations and circumstances: “Man at last knows that he is alone in the unfeeling immensity of the universe, out of which he emerged only by chance. Neither his destiny nor his duty have been written down. The kingdom above or the darkness below: it is for him to choose.” [Monod’s title, Chance and Necessity, is from Democritus’ dictum “Everything in the universe is the fruit of chance of chance and necessity.”]  

That we live in a world that is indifferent to our hopes and suffering was the reason for Monod to inquire into the meaning of life, which, for Camus, was “the most urgent of questions.” Camus was often branded an existentialist, but unlike many contemporary existentialist thinkers, Camus vehemently rejected nihilism. In The Myth of Sisyphus, he wrote that Sisyphus gave his life meaning by choosing to believe that he remained the master of his own fate, even though he was condemned to rolling his rock uphill each day, only to have it roll back down.

On the opening page of Chance and Necessity, Monod includes a lengthy quotation from the closing paragraphs of The Myth of Sisyphus. “The struggle itself towards the heights is enough to fill a man’s heart…One must imagine Sisyphus happy.” Camus is advocating that we oppose the certainty of death in an uncaring Universe by living life to the fullest. For Monod, life is like Sisyphus, pushing its rock uphill. The end might be bleak, but “the struggle towards the heights is enough to fill a man’s heart.”]

By 1944, the liberation of Paris was imminent, Combat went from a monthly publication to a daily one, and the paper chanced to circulate in the open. Camus was still writing his editorials anonymously. And when his identity was finally revealed, his inspiring, eloquent words resulted in his widespread public acclaim.

Monod and Camus were very likely aware of each other at this point in our saga, but they had not yet met. Their meeting would happen after the liberation of France, and it would be in response to a new totalitarian threat; from the Soviet Union. It transpired as follows.

In 1948, Monod was working full-time on his research at the Pasteur Institute, when events in the Soviet Union moved him to write a stirring editorial that appeared on the front page of Combat. [Camus had left Combat the previous year, after it became a commercial paper.] Monod’s piece was in response to a pseudoscientific doctrine advanced by Stalin’s head of Soviet agriculture, Trofim Lysenko, which asserted that organisms could swiftly change their genetic endowment in response to a new environment. [Lysenko’s doctrine is reminiscent of discredited Lamarckian doctrine, also known as heritability of acquired characteristics—i.e., the premise that if an organism changes to adapt to an environment, it can pass on those changes to its offspring.] Lysenko based his doctrine on his purported discovery of a means to enable winter wheat to be sown in the spring.

Stalin embraced Lysenkoism—during an acute grain shortage in Russia—since it was in accord with his ideology to create the New Soviet Man. Stalin also banned all dissent against Lysenko’s doctrine. Consequently, traditional Russian geneticists were exiled or murdered, Mendelian genetics was no longer practiced in the Soviet Union, and Soviet agriculture suffered severely.

Monod was roused to write his editorial after French Communist newspapers began to widely disseminate Lysenko’s doctrine in France. One Party newspaper proclaimed Lysenko’s discovery “A Great Scientific Event,” and further asserted that the notion of evolution by natural selection was a racist form of thinking, in harmony with Nazi doctrine (7). Another Party newspaper condemned Mendelian genetics for being “bourgeois, metaphysical and reactionary,” while claiming that it must be false because it is reactionary; having been invented by an Austrian monk. In Contrast, Lysenkoism is true because it is progressive and proletarian.

A Party member’s position on Lysenko indeed had become a gauge of his commitment to Stalin’s Soviet cause. But for Monod, the Soviet embrace of Lysenko was “senseless, monstrous, unbelievable.” As expected, Monod’s article was strongly condemned by the powerful French Communist Party, which enjoyed broad support from both intellectuals and workers; many of whom saw the Soviet Union as a model for a French socialist state. In any case, the Party’s strong backlash inspired Monod to “make his life’s goal a crusade against anti-scientific, religious metaphysics, whether it be from Church or State.” Importantly, a separate consequence of the Lysenko affair was that it influenced François Jacob to focus his research in the field of genetics. See Aside 7.

[Aside 7: Ironically, the observation that Jacob and Monod initially set out to explain looked remarkably like Lysenkoism. When E. coli are fed a solution of glucose and lactose, they grow rapidly until glucose—their preferred carbon source—is depleted. Only then, they turn to metabolizing lactose. But, in contrast to Lysenko’s doctrine, Jacob and Monod showed that when E. coli “adapts” to lactose, it does so without changing its genes. Instead, the genes encoding the enzymes that metabolize lactose lie dormant until lactose induces them, under conditions in which glucose is not available. That is, Jacob and Monod determined that lactose regulates lactose metabolism in the cell by acting as an inducer of genes that already exist in the cell; as opposed to lactose causing the cell to undergo a Lamarckian acquisition of a genetic characteristic. In so doing, Jacob and Monod created the now well-established paradigm of inducers, regulators, regulator genes, and operators.]

While Monod was crusading against Lysenkoism, Camus was having his own feud, in public, with Sartre, who had chastised him for his anti-Soviet stance. Camus had once been a Communist, in Algeria, mainly because he was troubled by the way in which the European French treated the native Algerians. However, he was never very sympathetic to the Marxist cause. Monod too had once been a member of the Communist Party; but only because it enabled him to have a voice in the running of the Resistance. In any case, Camus seized upon Monod’s condemnation of Lysenkoism in his feud with Sartre.

Our two main protagonists finally met when Camus co-founded the anti-Stalin, anti-totalitarian Groupes de Liaison Internationale. Monod attended one of the group’s meetings. There, he, and Camus, discovering that they shared much in common, forged their friendship. Carroll writes: “Camus, who so treasured the sense of solidarity that existed among the Resistance, had in Monod a new comrade who shared both the deep bond of that wartime experience and an unqualified opposition to a new common enemy.”

As noted, Monod’s views on the meaning of life owed much to Camus. Likewise, Camus learned from Monod. Camus not only used Monod’s case against Lysenko in his dispute with Sartre, but he also “borrowed” from Monod in The Rebel; in which Camus argued that revolution inevitably leads to tyranny. In any event, after Camus and Monod had separately fought the Nazis, they were now united against another oppressor—the totalitarian state run by Stalin. [Camus’ anti-Soviet stance cost him the friendships of many French intellectuals on the left. He and Sartre never spoke to each other again.]

Monod was also troubled by the situation of scientists working under Eastern European Soviet regimes. In 1959, he organized the escape into Austria of Hungarian biochemist Agnes Ullman (who participated in the failed Hungarian uprising of 1956), and her husband, also a scientist. Earlier, in 1958, Agnes Ullman managed to visit Monod at the Pasteur Institute, and confided to him that she and her husband wanted to defect from Hungary. Monod maintained contact with the Ullmans in Hungary, using coded messages, written in invisible ink, which turned blue when exposed to iodine. The Ullmans finally crossed into Austria, hidden underneath a bathtub, in a compartment of a pull-along camping trailer. See Aside 8.

[Aside 8. Agnes Ullmann, became Monod’s long-time close collaborator at the Pasteur Institute. Now retired, she was carrying out research at the Pasteur Institute as recently as 2012; 53 years after her rescue from Hungary. At the Institute, she collaborated with Monod on characterizing the lac operon promoter, on complementation between β-galactosidase subunits, and on the role of cAMP in overcoming the repressive effect of glucose (catabolite repression) on lactose metabolism in E. coli.]

There are numerous other instances in which Monod stepped forward to fight injustice and defend human rights. In 1952, he wrote a letter in Science that might have been “ripped from today’s headlines.” It protested the U.S. government’s rejection of visa requests for himself and other Europeans who had once been Communists. Monod also condemned the treatment of Jews in the Soviet Union, while continuing to speak out against Soviet totalitarianism in general. And, in 1965, shortly after Monod, Lwoff, and Jacob received word of their Nobel Prizes, they publicly appealed to the French government to allow the use of contraceptives, and the legalization of abortion. See Aside 9.

[Aside 9: Jacob too was devoted to the defense of human rights. He chaired a committee of the French Academy of Sciences that supported persecuted scientists living under totalitarian regimes, and he worked for the release of those who had been imprisoned for their political views. Moreover, he forcefully advocated for the public support of the biological and medical sciences. What’s more, Jacob also had a distinguished writing career that produced a series of acclaimed books, including The Logic of Life: A History of Heredity; Of Flies, Mice and Men; The Possible and the Actual, and his memoir, The Statue Within. In Joshua Lederberg’s review of the latter for The Scientist, he stated:As a work of literature, it evokes unmistakable overtones of Rousseau, Proust, and Sartre.” In Jon Beckwith’s view, all of Jacob’s books are “written in a fluid and elegant style” Others refer to the “clarity and grace” of Jacob’s writing. See reference 8 for more on Jacob.]

In 1966, Martin Luther King Jr. and Harry Belafonte visited France to raise funds for the Southern Christian Leadership Conference (SCLC). Remarkably, Monod was chosen to introduce King to a crowd of 5,000 people at Paris’ Palais des Sports. Belafonte was introduced by French singer and actor Yves Montand (9).

Coretta Scott King shaking hands with Jacques Monod, as Martin Luther King Jr. looks on. From l-r: French actress Simone Signoret, Harry Belafonte, French actor and singer Yves Montand. 29 March 1966, at a meeting of the “Movement for the Peace.”

The intellectual lives of Monod and Camus played out in entirely different areas. Yet the parallels were striking. Each, in his way, searched for meaning in life. Moreover, each put his life on the line to oppose ignorance, injustice, and totalitarianism. And, it is clear from their correspondences that they were dear to each other. Here is the note from Monod that elicited Camus’ response at the top of this post.

My dear Camus,

My emotion and my joy are profound. There were many times when I felt like thanking you for your friendship, for what you are, for what you managed to express with such purity and strength, and that I had likewise experienced. I wish that this dazzling honor would also appear to you, in some small part, as a token of friendship and of personal, intimate recognition. I would not dare coming to see you right now, but I embrace you fraternally.

Jacques Monod

This piece ends with a few personal thoughts. Jacques Monod was a Nobel Prize-winning scientist, a hero of the French Resistance, a rescuer of persecuted scientists from behind the Iron Curtain, and a leading voice against tyranny and oppression. And, he was also blessed with dashing good looks. I remember well the women among my fellow graduate students in the 1960s finding him to be very attractive. But, on a more serious note: Today, when political and religious blocs dismiss evidence-based science in favor of alternative ‘facts’ in order to advance their ideologies, and when they are tacitly aided by a press that all too often gives equal validity to all points of view, and while scientists seem to be groping for an effective response, one can hope that scientists with the courage, eloquence, and eminence of Jacques Monod and Francois Jacob might emerge to take up the cause of science and reason. Meanwhile, it is especially important for young scientists, and the public, to be aware of the examples set by these men. See Aside 10.

[Aside 10: The following is from a March 8, 2017 editorial in Nature.  “Last week, state legislators in Iowa introduced a bill that would require teachers in state public schools to include ‘opposing points of view or beliefs’ in lessons on topics including global warming, evolution and the origins of life… Since last month, Indiana, Idaho, Alabama, Texas, Oklahoma and Florida have all introduced and discussed similar tweaks to the way in which they want to educate their children… Although these proposed changes are typically presented by their supporters as giving teachers the chance to discuss genuine scientific controversies, in truth they are (very) thinly veiled attempts to pursue political and religious agendas that have no place in school science lessons — for whatever age. They seek to import the alternative facts and misleading rhetoric of the new federal government and to impose it on children who deserve much better from those elected to serve them.”]


  1. A Most “Elegant” Experiment: Sydney Brenner, Francois Jacob, Mathew Meselson, and the Discovery of Messenger RNA , Posted on the blog October 6, 2016.
  2. Sean B. Carroll, Brave Genius: A Scientist, a Philosopher, and their Daring Adventures from the French Resistance to the Nobel Prize, Crown, 2013.
  3. Genealogies and a Selective History of Lysogeny: Featuring Friedrich Loeffler, Emile Roux, Andre Lwoff, Elie Wollman, and Francois Jacob, Posted on the blog January 28, 2015 (8).
  4. Agnes Ullmann, In Memoriam: Jacques Monod (1910–1976), Genome Biology and Evolution 3:1025-1033. 2011, DOI: https://doi.org/10.1093/gbe/evr024.
  5. Louis Pasteur: One Step Away from Discovering Viruses, Posted on the blog January 7, 2015.
  6. Dufour, H. D., and S. B. Carroll, History: Great myths die hard, Nature 502:32–33, 2013.
  7. John Marks, Jacques Monod, François Jacob, and the Lysenko Affair: Boundary Work, L’Esprit Créateur: Genetics and French Culture. 52:75-88.
  8. Beckwith, J., and M. Yaniv, Francois Jacob (1920-2013), Current Biology 23:R422-R425, 2013.
  9. Remembering Dr. Martin Luther King Jr., CBS Minnesota, January 19, 2013, 3:51 PM.

A Most “Elegant” Experiment: Sydney Brenner, Francois Jacob, Mathew Meselson, and the Discovery of Messenger RNA

What was the most “elegant” experiment ever? Many molecular biologists, who were active during the so-called “golden age” of the 1950s and 1960s, might opt for the 1958 experiment of Mathew Meselson and Franklin Stahl, which demonstrated the semiconservative replication of DNA (1). My choice is the 1960 experiment by Sidney Brenner, Francois Jacob, and Matt Meselson, which established the existence of messenger RNA (mRNA) (2). The story behind the discovery is an appropriate topic for the blog since bacteriophage T2 had a key role to play. It is told here, largely through the words of one of its contributors, Pasteur Institute scientist and Nobel laureate, Francois Jacob (3).

Imagine for the moment that we are back in the late 1950s, at a time when the precise role of RNA was not yet known. However, pertinent evidence was accumulating, which implied that RNA had a role in protein synthesis. For example, cellular RNA levels correlated with the levels of protein synthesis.

But what might the role of RNA be? The example of eukaryotic cells seemed to indicate that DNA could not directly serve as the template for protein synthesis. The DNA in those cells is contained within the membrane-bounded nucleus, whereas protein synthesis occurs in the cytoplasm. Might RNA then serve as an intermediate information carrier?

Jacob, and others, knew that protein synthesis took place in the cytoplasm, on tiny granules called ribosomes. Moreover, “for each gene there were corresponding ribosomes specifically charged with producing the corresponding protein (3).” This remark might seem to suggest an accurate view of protein synthesis. Nonetheless, the understanding of ribosomes at the time was fundamentally wrong. Each gene was thought to be transcribed to a unique RNA that became an integral component of a ribosome. Moreover, that integral RNA was thought to confer on the ribosome the specificity to support the synthesis of only the one protein that corresponded to that particular RNA—a scenario under which an entire ribosome needed to be produced de novo to support the translation of a gene.

With that view of ribosomes in mind, Jacob was troubled by the results from an earlier experiment, carried out in 1957 by Arthur Pardee, Jacob himself, and Jacques Monod—the famous (and also quite “elegant”) PaJaMa experiment (4). In this experiment, the Lac gene of an Hfr (male) strain of E. coli is transferred to a Lac-minus, F-minus (female) strain. [This experiment is famous because it was carried out under experimental conditions which enabled the three researchers to demonstrate the existence of a previously unknown regulatory molecule; the “repressor.”] What troubled Jacob was that the Lac gene of the donor E. coli strain was expressed “immediately upon entry of the gene…”—a result not in accord with the thinking of the day about the nature of ribosomes, and the way in which they translated genes into proteins.

It seemed impossible to Jacob that ribosomes, which are complex structures composed of proteins and RNA, could be produced quickly enough to enable the virtually immediate translation of the transferred Lac gene, as had been seen in the PaJaMa experiment. What’s more, the prevailing view of ribosomes also did not fit “with the existence of units of activity recently baptized ‘operons,’ that contained several genes. Nor with a regulation functioning directly on the DNA through the intermediary of a switch, now called an ‘operator.’”

The “perplexity prevailing in the Pasteur group” led to a new line of thought— “either direct synthesis of the protein on DNA itself, with no intermediary; or production of an unstable intermediary, probably an RNA with rapid renewal. But the former hypotheses seemed highly improbable and the latter without a chemical basis, without any trace of a molecule that could substantiate it.”

In 1959 Jacob attended a colloquium on microbial genetics in Copenhagen, where he intended to discuss this conundrum. “A small group attended, including notably Jim Watson, Francis Crick, Seymour Benzer, Sydney Brenner, Jacques (Monod), and even the physicist Niels Bohr. Courteous as ever, Jim Watson spent most of the sessions ostentatiously reading a newspaper. So, when it came time for him to speak, everyone took from his pocket a newspaper and began to read it”

When Jacob’s turn to speak came, he raised the possibility of a need for an unstable intermediary, which he called X. “No one reacted. No one batted an eyelash. No one asked a question. Jim continued to read his newspaper.”

“A new opportunity to discuss protein synthesis arose around Easter 1960 in Cambridge (England), in Sydney’s small apartment in King’s College, where he was a Fellow.” Although the meeting that morning was casual, several heavy hitters were present, including Francis Crick, Leslie Orgel, and Ole Maaloe, in addition to Jacob and Brenner.

Crick and Brenner discussed the results of a recent experiment carried out by Pardee and Monica Riley (Pardee’s student at the time). “They had succeeded in charging the DNA of male bacteria with radioactive phosphorus; in making them transfer to females the gene of galactosidase; in letting it synthesize the enzyme for some minutes; and then in destroying the gene through the disintegration of the radioactive phosphorus. The result was clear: once the gene was destroyed, all synthesis stopped. No gene, no enzyme. Which excluded any possibility of a stable intermediary.” [Recall the thinking that stable ribosomes contained an integral RNA that conferred its specificity.]

“At this precise point, Francis and Sydney leaped to their feet. Began to gesticulate. To argue at top speed in great agitation. A red-faced Francis. A Sydney with bristling eyebrows. The two talked at once, all but shouting. Each trying to anticipate the other. To explain to the other what had suddenly come to mind. All this at a clip that left my English far behind. For some minutes, it was impossible to follow them, just as it would have been impossible for them to follow a discussion in French between Jacques (Monod) and me. What had set off Francis and Sydney was, once again, a connection between the lactose system and phage. After infecting the colon bacillus, certain highly virulent phages blocked the synthesis of new ribosomes. As had been shown by two American Researchers, Elliot Volkin and Lazarus Astrachan, the only RNA then synthesized had two remarkable properties: on the one hand, unlike ribosomal RNA, it had the same base composition as DNA; on the other hand, it renewed itself very quickly. Exactly the properties required for what we called X, the unstable intermediary we had postulated for galactosidase. Why, in Paris, when we were looking for a support material for X, had we not thought of this phage RNA? Why had I not thought of it? Ignorance? Stupidity? Oversight? Misreading of the literature? Failure of judgment? A little of all these, no doubt. A mixture that, as in a detective novel, had made us fail to spot the murderer, the molecule responsible. In the last analysis, however, what mattered was that X, the unstable intermediary, was materializing…it had to be shown that all this was not a dream; that this RNA of the phage was indeed the unstable intermediary functioning in the synthesis of proteins: the issue that we and Sydney immediately decided to take up. …” See Aside 1.

[Aside 1: Volkin and Astrachan, at the Oak Ridge National Laboratory in Tennessee, showed that there actually are two kinds of RNA seen during phage infection—a stable type found in ribosomes (now known as ribosomal RNA, which does not have the same base composition as the DNA ), and an unstable, rapidly turning over type, that has the same base composition as the viral DNA, but not the bacterial DNA (5). Transfer RNA remained to be discovered.]

That afternoon, Jacob and Brenner found out that they each had been invited to spend a month (June) at the California Institute of Technology. Brenner’s invitation came from Matt Meselson, and Jacob’s from Max Delbruck. “A unique opportunity to work together to demonstrate the nature and role of X.” Importantly, Meselson recently developed a technique that would make the discovery possible.

That evening, at a party given by Crick and his wife, Jacob and Brenner discussed the experiment that they were envisioning. But: “It was difficult to isolate ourselves at such a brilliant, lively gathering, with all the people crowding around us, talking, shouting, laughing, singing, dancing. Nevertheless, squeezed up next to a little table as though on a desert island, we went on, in the rhythm of our own excitement, discussing our new model and the preparations for experiments at Caltech.”

In their new concept of protein synthesis: “The ribosomes had lost all specificity. They had become simple machines for assembling amino acids to form proteins of any kind, like tape recorders that can play any kind of music depending on the magnetic tape inserted in them. In protein synthesis, it was X, the unstable RNA copied on a gene, that had to play the role of the magnetic tape, associating with the ribosomes to dictate to them a particular sequence of amino acids corresponding to a particular protein.” Thus, the experiment would be to “show that the unstable RNA, synthesized after infection of a colon bacillus by the virulent phage, associated with pre-existing ribosomes, synthesized before infection, to produce the proteins of the phage.”

A key problem would be to distinguish ribosomes made before infection from any ribosomes that might be made after infection. Their solution would be provided by Matt Meselson’s new technique in which “he marked macromolecules by cultivating bacteria in heavy isotopes before putting them back in a normal environment. Using ultracentrifugation, he could then separate the marked molecules along gradients of density…”

Thus, the plan was to grow cells for several generations in medium containing the heavy isotopes 15N and 13C as the sole nitrogen and carbon sources, respectively. In this way, essentially all ribosomes present in the cells would be “heavy”. Next, the cells would be washed and placed in medium containing the normal isotopes, 14N and 12C. Then, the cells would immediately be infected with the phages. Any new ribosomes made after the infection got underway would be “light”.

Here is a key point. Recall that Volkin and Astrachan showed that the only RNA that is made after infection is the unstable RNA, which has the same base composition as the phage DNA. [That is so because the phage shuts down host transcription and translation.] Consequently, this phage RNA can be specifically labeled by adding 32P to the infected cultures (5). Brenner, Jacob, and Meselson hoped to find this rapidly turning-over phage-specific RNA in the density gradients, in association with the old heavy ribosomes that were made before infection. “If we were right, if our hypothesis was correct, the radioactivity of the RNA had to be associated, in the gradients, with the band of “heavy” ribosomes.”

However: “We were not succeeding.” The problem that was frustrating their efforts was that the ribosomes were unstable in the density gradients. “In vain did we try to check through the experiment, to modify it, to change a detail here and there. It was now three weeks since Sydney Brenner and I had arrived at the California Institute of Technology. We had come for the sole purpose of carrying out this experiment with Matt Meselson. An experiment that we had no doubt was going to change the world. But the gods were still against us. Nothing worked.”

“Our fine confidence at the start had evaporated. Disheartened, Meselson had departed-to get married! Sydney and I talked about going back to Europe. In a burst of compassion, a biologist by the name of Hildegaard had taken us under her wing and, to give us a change of scene, driven us to a nearby beach. There we were, collapsed on the sand, stranded in the sunlight like beached whales. My head felt empty. Frowning, knitting his heavy eyebrows, with a nasty look, Sydney gazed at the horizon without saying a word. Never yet had I seen Sydney Brenner in such a state. Never seen him silent…And our time was running out. For, come what may, Sydney and I had decided to leave at month’s end.”

“Hildegaard tried to tell us stories to lighten the atmosphere. But we were not listening. Suddenly, Sydney gives a shout. He leaps up, yelling, “The magnesium! It’s the magnesium!” Immediately we get back in Hildegaard’s car and race to the lab to run the experiment one last time. We then add a lot of magnesium… Sydney had been right. It was indeed the magnesium that gave the ribosomes their cohesion. But the usual quantities were insufficient in the density gradients used to separate heavy and light compounds. This time we added plenty of magnesium. The result was spectacular. Eyes glued to the Geiger counter, our throats tight, we tracked each successive figure as it came to take its place in exactly the order we had been expecting. And as the last sample was counted, a double shout of joy shook the basement at Caltech…This was merely one experiment, performed in extremis… But we now knew that we had won. That our conception explained the transfers of information in the synthesis of proteins…Scarcely was the experiment over than we gave a seminar at Caltech to demonstrate the existence of X and its role as magnetic tape. No one believed us. The next day we left, each to his own home. The bet had paid off. In the nick of time.”

Apropos our Virology blog, this experiment also showed that viruses subvert the cellular protein synthesis machinery for their own ends.


Nobel laureate Sidney Brenner was the main subject of two earlier posts—The Phage in the Letter, reposted September 8, 2016 and Sidney Brenner: Only Joking, January 5, 2014 (6, 7). Each of these posts highlighted Brenner’s mischievous sense of humor. Jacob offers more insight into Brenner’s personality in his account of the episode on the beach with Hildegaard: “There we were, collapsed on the sand, stranded in the sunlight like beached whales. My head felt empty. Frowning, knitting his heavy eyebrows, with a nasty look, Sydney gazed at the horizon without saying a word. Never yet had I seen Sydney Brenner in such a state. Never seen him silent. On the contrary, he was an indefatigable talker at every opportunity. A tireless storyteller, able to discourse for days and nights on end. Interminable monologues on every conceivable subject. Science, politics, philosophy, literature, anything that cropped up. With stories he made up as he went along. Generously laced with jokes. With nasty cracks, too, at the expense of just about everyone. An excellent actor, he could render a speech in Hungarian, a lecture in Japanese. Mimic Stalin or Franco. Even himself. He went without a break from one register to another. A sort of fireworks whose effects he gauged from the expressions of the people around him.”

In the September 8th reposting I wrote: “While Brenner’s work as a molecular biology pioneer may have justified a Nobel Prize, he received the award in 2002 for his later studies of the nematode Caenorhabditis elegans, in which his research group traced the fate of each cell from the zygote right through to the adult worm. Their work established C. Elegans as a model system that is now studied in hundreds of laboratories all over the world (6).”

Jacob collaborated with Jacques Monod to elucidate the genetic switch that regulates beta-galactosidase synthesis in E. coli. Their collaboration established the concepts of regulator genes and operons, for which they shared in the 1965 Nobel Prize for physiology or medicine.

François Jacob (left), with Jacques Monod and André Lwoff. This Pasteur Institute threesome shared the 1965 Nobel Prize for Physiology or Medicine
François Jacob (left), with Jacques Monod and André Lwoff. This Pasteur Institute threesome shared the 1965 Nobel Prize for Physiology or Medicine “for their discoveries concerning genetic control of enzyme and virus synthesis.” Lwoff’s share of the award was for his pioneering studies of lysogeny (8).

In 1940, Jacob, who was Jewish, left medical school in occupied France to join Free French Forces in London. He then served as a medical officer in North Africa, where he was wounded, and was wounded again, this time severely, at Normandy in August 1944. Monod too was active in the French Resistance, during the Nazi occupation of Paris. He eventually become chief of staff of the French Forces of the Interior. In that capacity, he helped to prepare for the Allied landings in Normandy. Monod and Jacob each received France’s highest honors for their wartime service. For more on Jacob, see Genealogies and a Selective History of Lysogeny: Featuring Friedrich Loeffler, Emile Roux, Andre Lwoff, Elie Wollman, and Francois Jacob, posted January 28, 2015 (8).

Matt Meselson (still at Harvard at 86 years in age) is best known for showing that DNA replication is semi-conservative and for his part in the discovery of messenger RNA. Jacob tells us that at the time of their collaboration at Cal Tech: “He (Meselson) was haunted by the Cold War, by the need to establish better relations with the Soviet Union. In his soft voice, he could discourse for hours on strategy, tactics, nuclear arms, the Rand Corporation, first strikes, reprisals, annihilation.” Meselson later helped to persuade President Richard Nixon to renounce biological and chemical weapons, and to support an international treaty (the 1972  Biological Weapons Convention) banning the use of biological agents.


  1. Meselson M and FW Stahl, 1958. The Replication of DNA in Escherichia coli, Proceeding of the National Academy of Sciences USA. 44:671–82.
  2. Brenner S, F Jacob, and M Meselson, 1961. An Unstable Intermediate Carrying Information from Genes to Ribosomes for Protein Synthesis, Nature 190:576-80.
  3. Francois Jacob, The Statue Within: An Autobiography, English language translation copyright 1988 Basic Books Inc.
  4. Pardee, AB, F Jacob, and J Monod, 1959. The genetic control and cytoplasmic expression of ‘inducibility’ in the synthesis of β-galactosidase by coli, Journal of Molecular Biology 1:165–178.
  5. Volkin E and L Astrachan. 1956. Phosphorus Incorporation in Escherichia coli Ribonucleic Acid after Infection with Bacteriophage T2. Virology 2:149-161.
  6. The Phage in the Letter. Reposted on the blog September 8, 2016.
  7. Sidney Brenner: Only Joking. Posted on the blog January 5, 2014 (find under Archives, January 2014).
  8.  Genealogies and a Selective History of Lysogeny: Featuring Friedrich Loeffler, Emile Roux, Andre Lwoff, Elie Wollman, and Francois Jacob. Posted on the blog January 28, 2015.

Genealogies and a Selective History of Lysogeny: Featuring Friedrich Loeffler, Emile Roux, Andre Lwoff, Elie Wollman, and Francois Jacob

I am intrigued by the genealogies of our leading scientists, since their mentors too were often preeminent scientists. Earlier postings noted the example of Jonas Salk, who did postgraduate studies under Thomas Francis; one of the great pioneers of medical virology, perhaps best known for developing the first influenza vaccine (1, 2). James Watson, who did his doctoral studies in Salvatore Luria’s laboratory, and Renato Dulbecco, who trained under both Luria and Max Delbruck (3), are other examples. In fact, Watson and Dulbecco shared a lab bench in Luria’s lab. Howard Temin did his doctoral (and postdoctoral studies too) in Dulbecco’s lab (4). And Delbruck, who hugely influenced the new science of molecular biology, did his doctoral studies under Max Born, the 1954 Nobel Laureate in physics. Moreover, Delbruck later served as an assistant to Lisa Meitner (5).

Important research paths were undertaken, and major contributions were made, which resulted from less formal interactions between budding young scientists and top scientists of the day. Howard Temin’s chance encounter with Harry Rubin, while on a mission to Dulbecco’s lab, is a case in point (4).

Our last posting told how Louis Pasteur came within a whisker of adding the discovery of viruses to his list of extraordinary achievements (6). Robert Koch played a part in that story for developing his famous postulates, which provided the standard for demonstrating that a particular microbe causes a particular disease.

The Pasteur article also noted that in 1898 Friedrich Loeffler and Paul Frosch isolated the foot and mouth disease virus; the first virus isolated from animals. However, the piece did not point up that Loeffler had trained under Robert Koch. Also, it did not underscore the special significance of what Loeffler and Frosch achieved. In brief, by the 1890s Dmitry Ivanovsky and Martinus Beijerinck had independently discovered that the agent responsible for tobacco mosaic disease passes through bacterium-proof filters. Nevertheless, neither Ivanovsy nor Beijerinck appreciated the implication of their observation. Ivanovsky believed his filters might be defective, while Beijerinck thought the disease was caused by a “living liquid.” In contrast, Loeffler and Frosch, in addition to isolating the first virus that is pathogenic in animals, also carefully considered all possible explanations for their experimental findings, and then were the first to conclude the existence of a kind of microbe too small to be retained by bacterium-proof filters, and too small to be seen under a microscope, and that will not grow on laboratory culture media. They also correctly predicted that smallpox, cowpox, cattle plague, and measles are similarly caused by a “filterable virus.”

Loeffler made another major discovery, fourteen years earlier, in 1884, when he used his mentor’s postulates to identify the bacterium that causes diphtheria, Corynebacterium diphtheriae. Importantly, Loeffler also discovered that when he injected C. diphtheriae into animals, the microbe did not need to spread to the tissues it damaged. This observation led Loeffler to propose the bacteria were secreting a poison or toxin that spread to the remote sites and caused disease there.

Loeffler’s idea of a toxin was a new concept that subsequently was confirmed by Emile Roux, who had been Louis Pasteur’s assistant (6). Using bacterium-proof filters developed by Charles Chamberland in Pasteur’s lab, Roux showed that injecting animals with sterile filtrates of C. diphtheriae cultures caused death with a pathology characteristic of actual diphtheria. Roux was also a co-founder of the Pasteur Institute, where he was responsible for the production of diphtheria anti-toxin; the first effective diphtheria therapy. See Aside 1.

[Aside 1: Earlier, Roux suggested the approach Pasteur used to generate attenuated rabies virus for the Pasteur rabies vaccine (aging spinal cords from rabbits that succumbed to experimental rabies infections of their spinal cords). Roux later withdrew from the rabies project because of a disagreement with Pasteur over whether the rabies vaccine might be safe for use in humans (6).]

So, Loeffler and Roux trained under Koch and Pasteur, respectively. But why might toxin production by C. diphtheriae interest virologists. Well, in 1951, Victor Freeman at the University of Washington showed that the lethal toxins produced by C. diphtheriae (and by Clostridium botulinum as well) are the products of lysogenic bacteriophage carried by the bacteria. This was shown by the finding that avirulent strains of these bacteria became virulent when infected with phages that could be induced from virulent strains. So, are diphtheria and botulism due to bacteria or to viruses? Our chain of genealogies continues with a selective history of lysogeny.

Almost from the beginning of phage research (bacteriophage were discovered independently by Frederick Twort in Great Britain in 1915 and by Félix d’Hérelle in France in 1917), some seemingly normal bacterial cultures were observed to generate phage. Initially, this phenomenon was thought to be a sign of a smoldering, steady state kind of persistent phage infection. Then, during the 1920s and 1930s, the French bacteriologists, Eugene Wollman and his wife Elizabeth, working together on Bacillus megatherium at the Pasteur Institute, provided evidence that instead of a steady state infection, the phage actually enter into a latent form in their host cells; a form in which they might be harmlessly passed from one cell generation to the next. [Considering the state of knowledge back then, note the insightfulness of Eugene Wollman’s 1928 comment, “the two notions of heredity and infection which seemed so completely distinct and in some ways incompatible, . . . almost merge under certain conditions.”] See Aside 2.

[Aside 2: Since some bacterial strains would, on occasion, spontaneously undergo lysis and release bacteriophage, the cryptic bacteriophage they carried were called “lysogenic.” Thus, it is a bit odd that “lysogeny” eventually came to refer to the temperate relationship between these phages and their host cells.]

In the late 1930s, the Wollmans developed a close friendship with Andre Lwoff, their new colleague at the Pasteur Institute. The Wollmans introduced Lwoff to their ideas about lysogeny, but, as Lwoff confesses, he was not then impressed by bacteriophage (7).

The Nazi occupation of Paris during the Second World War began in 1940. From then on, the Jewish Wollmans were prevented from publishing their research findings. Nevertheless, they continued their research at the Pasteur Institute until 1943, when they were seized by the Nazis and sent to Auschwitz. They never were heard from again. Their friend, Lwoff, grieved their loss and became active in the French resistance, gathering intelligence for the Allies, while also hiding downed American airmen in his apartment.

After the war, Lwoff received several honors from the French government for his efforts against the Nazis. He also returned to his research at the Pasteur Institute, studying the genetics of Moraxella; a bacterial pathogen of the human respiratory tract. Because of his work as a microbial geneticist, he was invited to the 1946 Cold Spring Harbor Symposium, where he met Max Delbruck. And as happened to others, meeting Delbruck resulted in Lwoff being seduced by bacteriophage.

Andre Lwoff
Andre Lwoff

Back in Paris, Lwoff’s passionate interest in phages was heightened further by discussions with Jacques Monod, a friend of Max Delbruck, and Lwoff’s neighbor in the attic of the Pasteur Institute. Although Monod was Lwoff’s junior colleague (in fact, it was Lwoff who first stirred Monod’s interest in microbiology), Lwoff’s conversations with the future Nobel Laureate resulted in Lwoff becoming intensely fascinated by lysogeny, which he began to study in 1949 (7).

Because of Lwoff’s earlier friendship with the Wollmans, he chose to study a lysogenic strain of B. megatarium. And, making use of techniques he learned from Renato Dulbecco during a brief stint at Cal Tech, he was able to follow a single lysogenic bacterium, which enabled him to observe that a bacterium could go through multiple rounds of replication without liberating virus. What’s more, he discovered that the phages are released in a burst when the cell lyses, thereby dispelling the still current notion that phages are liberated continuously by lysogenic bacteria. Furthermore, Lwoff showed that lysogenic bacteria usually do not contain phage particles, since none are detected when the cells are experimentally lysed with lysozyme; confirming the earlier (1937) findings of the Wollmans.

Lwoff went on to show that temperate phage genomes are maintained in a previously unknown integrated state in their host cell, and he gave the integrated phage genomes a name, “prophage.” He also discovered, unexpectedly, that irradiating lysogenic bacteria with ultraviolet light could induce the temperate phages to emerge from their latent state, and then replicate in, and lyse their host cells. And, he discovered that the phages lyse their host bacterial cells by producing enzymes that destroy bacterial cell walls.


Lwoff’s elucidation of the fundamental nature of lysogeny in bacteria would later provide a paradigm for the DNA tumor viruses, the herpesviruses, the oncogenic retroviruses, and HIV. He was awarded a share of the 1965 Nobel Prize for physiology or medicine for his lysogeny research. He shared the award with his fellow Pasteur Institute scientists, François Jacob and Jacques Monod, who received their awards for their pioneering studies of gene regulation in E. Coli.

A rather intriguing aspect of this story is that Lwoff was joined in his research on lysogeny at the Pasteur Institute by Elie Wollman; the son of Eugene and Elizabeth. Elie, born in 1917, escaped from the Nazis in Paris in 1940 and worked in the French resistance as a physician. In 1946, after the war, he came to the Pasteur Institute, where he took its microbiology course and then became Lwoff’s research assistant. Then, in 1947, Elie too happened to meet Max Delbruck (in Paris in this instance) and was invited to join the Cal Tech phage group, where he spent the next two years. See Aside 3.

Elie Wollman
Elie Wollman

[Aside 3: By the early 1940s, the then young Cal Tech “phage group,” headed by Max Delbruck, was on its way to becoming the World’s great center for phage research (5). However, the American group had little interest in lysogeny, since Delbrück neither believed in it, nor saw its importance. Instead, Delbruck was totally committed to the study of lytic phages. Then, during the late 1940s, Delbruck began to lose interest in molecular biology and looked for new research directions. When he thought of turning his attention to brain function, he asked his group to put together a series of seminars based on papers written by prominent neuroscientists of the day. Elie Wollman was the only member of the Cal Tech group who declined to participate in that endeavor, since he was totally committed to bacteriophage. Moreover, Elie was the one who finally convinced Delbruck that “such a thing as lysogeny does exist (7).”

Elie himself tells us that when he looked into a bibliographical index at Cal Tech, he came across an index card referring to his parent’s 1937 paper, which reported their finding that lysogenic cells contain a non-infectious form of the phage (8). “Delbruck’s comment on the card was “Nonsense.”]

After Eli’s two-year stint with Delbruck in Pasadena, he returned to the Pasteur Institute. Meanwhile, Francois Jacob had come to the Institute in the hope of beginning a research career in genetics under the tutelage of either Lwoff or Monod. Before that, in 1940, Jacob, who also was Jewish, left medical school in occupied France to join Free French Forces in London. He then served as a medical officer in North Africa, where he was wounded, and was later severely wounded at Normandy in August 1944, ending his dream of becoming a surgeon.

Francois Jacob
Francois Jacob

Initially, Jacob was spurned by both Lwoff and Monod, but was finally taken on by Lwoff, who suggested that he, Jacob, start work on “the induction of the prophage.” Jacob confesses he had no idea what that meant, but he accepted the project. Thus it came to pass that Francois Jacob and Elie Wollman established a particularly close and friendly collaboration, in which they turned their attention to the lambda prophage of E. coli. Their initial goal was to clarify the events of bacterial conjugation so that they might then understand the phenomenon whereby a temperate phage carried by a lysogenic bacterium is activated to undergo vegetative replication when that bacterium conjugates with, and transfers its integrated phage genome to a non-lysogenic bacterium.

To accomplish their goal, Wollman and Jacob began with experiments to locate the lambda genome on the chromosome of the lysogenic cell, and to follow its transfer during conjugation into a non-lysogenic recipient cell. A key feature of their experimental approach was conceived by Wollman (8). It was simply to interrupt conjugation between a lysogenic donor (Hfr) cell and a non-lysogenic recipient (F-minus) cell, at various times, by using a kitchen blender to break the mating cells apart. Using the blender to interrupt conjugation, and also using bacterial strains in which the recipient bacteria contained a set of mutations, and plating the mating mixture on selective media, Wollman and Jacob were able to measure the length of time required for each of the corresponding wild-type genes to be transferred from the Hfr donor cells to the F-minus recipient cells. Indeed, the time intervals between the appearances of each wild type gene in the recipient cells directly correlated with the distances between the genes, as independently determined by recombination frequencies. Thus, the interrupted mating approach gave Wollman and Jacob a new means to construct a genetic map of the bacterium, while also enabling them to locate the integrated phage genome on that map. Their experimental approach also allowed Wollman and Jacob to establish that, during conjugation, the donor cell’s genome is transferred linearly to the recipient cell. [The designation “Hfr” was coined by William Hayes because Hfr strains yielded a high frequency of recombinants when crossed with female strains.]

Importantly, Wollman and Jacob’s study of the activation of a lambda prophage when it enters a non-lysogenic F-minus recipient (a phenomenon they called “zygotic induction”), showed that the temperate state of the lambda prophage is maintained by some regulatory factor present in the cytoplasm of a lysogenic bacterium, but which is absent from a non-lysogenic one. It led to the discovery of a “genetic switch” that regulates the activation of the lysogenic bacteriophage, and of a phage-encoded repressor that controls the switch. These findings are among the first examples of gene regulation, and are credited with generating concepts such as the repressor/operator, which were firmed up by Jacob and Monod in their Nobel Prize-winning studies of the E. coli lac operon. See Aside 4.

[Aside 4: At the time of Wollman and Jacob’s interrupted mating experiments, kitchen blenders had not yet made their way to European stores. Eli was aware of these appliances only because of his earlier stint at Cal Tech. He bought a blender for his wife before returning to France, and then “borrowed” it for these experiments.]

Wollman and Jacob went on to demonstrate that the fertility or F factor, which confers maleness on the donor bacteria, can exist either in an integrated or an autonomous state. Indeed, this was the first description of such a genetic element, for which they coined the term “episome;” a term now largely replaced by “plasmid.”

Wollman and Jacob also determined that the E. coli chromosome is actually a closed circle. The background was as follows. Only one F factor is integrated into the chromosome of each Hfr strain, and that integration occurs at random. And, since the integrated F factor is the origin of the gene transfer process from the Hfr cell to the F-minus cell, interrupted mating experiments with different Hfr strains gave rise to maps with different times of entry for each gene. However, when these time-of-entry maps were taken together, their overlapping regions gave rise to a consistent circular map. The discovery of the circular E. coli chromosome was most intriguing, because all previously known genetic maps were linear. See Aside 5.

[Aside 5: The bacterial strain used by Wollman and Jacob in their study of zygotic induction was, in fact, the original laboratory strain of E. coli (i.e. E. coli K12) that was isolated in1922 from a patient with an intestinal disorder. In 1951, Esther Lederberg discovered that K12 is lysogenic. The discovery happened when she accidentally isolated non-lysogenic or “cured” derivatives of E. coli K12 that could be infected by samples of culture fluid from the parental K12 strain, which sporadically produced low levels of phage. Esther gave the lysogenic phage its name, lambda.

Esther was the wife of Joshua Lederberg, who received a Nobel Prize in 1958 for discovering sexual conjugation in bacteria, and the genetic recombination that might then ensue. Prior to Lederberg’s discoveries, genetic exchange and recombination were not believed to occur in bacteria. Lederberg’s Nobel award was shared with George Beadle and Edward Tatum (the latter was Lederberg’s postdoctoral mentor) for their work in genetics.

Joshua Lederberg, working with Norton Zinder (9), also discovered transduction, whereby a bacterial gene can be transferred from one bacterium to another by means of a bacteriophage vector. And, working together with Esther, Joshua discovered specialized transduction, whereby lambda phage transduces only those bacterial gene sequences in the vicinity of its integration site on its host chromosome. Esther and Joshua also worked together to develop the technique of replica plating, which enabled the selection of bacterial mutants from among hundreds of bacterial colonies on a plate and, more importantly perhaps, to provide direct proof of the spontaneous origin of mutants that have a selective advantage.]

In 1954 Elie Wollman was appointed a laboratory head in his own right at the Pasteur Institute. He retired from research in 1966 to become vice-director of the Institute, which he then rescued from a severe financial crisis. He continued to serve in that role for the next 20 years, while garnering numerous prestigious awards for his research and service.

Francois Jacob earned his doctorate in 1954 for his lysogeny studies. Then, realizing that he and Jacques Monod, his senior neighbor in the Pasteur Institute attic, were actually studying the same phenomenon, gene repression, he entered into a hugely productive collaboration with Monod that led to the elucidation of the genetic switch that regulates beta-galactosidase synthesis in E. coli (9). Their collaboration established the concepts of regulator genes, operons, and messenger RNA, for which they shared in the 1965 Nobel Prize for physiology or medicine, as noted above. See Asides 6 and 7.

Jacques Monod
Jacques Monod

[Aside 6: One of Jacob and Monod’s first experiments was the famous 1957 PaJaMa experiment, carried out in collaboration with Arthur Pardee, who was then on sabbatical at the Pasteur Institute. In brief (for aficionados), a Lac-positive, Hfr strain was grown in an inducer-free media, and then mated, still in an inducer-free media, with a Lac-minus, F-minus strain. (Note that the deletion in the Lac-minus, F-minus strain included the LacI gene, which encodes the yet to be discovered lac repressor.) As expected, in the absence of inducer, no beta-galactosidase is detected initially. But, after the donor DNA sequence, which bears the normal Lac genes (including LacI), is transferred to the Lac-minus recipient, it initially finds no repressor in the recipient cell and begins to synthesize beta-galactosidase. Then, as the donor cell’s lac repressor gene begins to be expressed in the recipient cell, in the inducer-free media, expression of the donor cell’s beta-galactosidase gene ceases. The PaJaMa experiment thus showed that the genetic regulation of enzymatic induction depends on a previously unknown regulatory molecule, the repressor.

Notice the similarity between the rationale for the PaJaMa experiment and that of the earlier Wollman and Jacob experiment on zygotic induction. In each instance, a process regulated by a repressor is suddenly in the repressor-free environment of a recipient cell.]

[Aside 7: In June of 1960, Francois Jacob, Matt Meslson, and Sidney Brenner came together in Max Delbruck’s Cal Tech lab to carry out an experiment that confirmed the existence of messenger RNA. The key to the experiment was their ability to distinguish ribosomes present in the cell before infection from ribosomes that might have been made after infection. They cleverly did that by incorporating heavy isotopes into ribosomes before infection, so that they might be separated in a density gradient from ribosome made after infection. Then, they showed that RNA produced by T2 phage in E. Coli associates with ribosomes that were synthesized by the cell entirely before infection. Furthermore, the new phage-specific RNA directs the synthesis of phage-specific proteins on those “old” ribosomes. I vote for this experiment as the most elegant in the entire history of molecular biology (11).]

Incidentally, during the Nazi occupation of Paris, Monod too was active in the French Resistance, eventually becoming chief of staff of the French Forces of the Interior. In that capacity, he helped to prepare for the Allied landings in Normandy. Monod and Jacob each received France’s highest honors for their wartime service.See Aside 7.

[Aside 7: I am singularly intrigued by the experiences of Andre Lwoff, Elie Wollman, Francois Jacob, and Jacques Monod during the Second World War. References 3 and 5 recount the wartime experiences of Renato Dulbecco and of Max Delbruck, and of other great scientists of the time. Other posts on the blog give accounts of virologists courageously placing themselves in harm’s way under different circumstances. Examples include pieces featuring Ciro de Quadros, Carlo Urbani, Peter Piot, and Walter Reed.]


(1) Jonas Salk and Albert Sabin: One of the Great Rivalries of Medical Science, Posted on the blog March 27, 2014.

(2) Ernest Goodpasture and the Egg in the Flu Vaccine, Posted on the blog November 25, 2014.

(3) Renato Dulbecco and the Beginnings of Quantitative Animal Virology, Posted on the blog, December 4, 2013.

(4) Howard Temin: “In from the Cold,” Posted on the blog December 16, 2013
(5) Max Delbruck, Lisa Meitner, Niels Bohr, and the Nazis, Posted on the blog November 12, 2013.

(6) Louis Pasteur: One Step Away from Discovering Viruses, Posted on the blog January 7, 2015.

(7) Lwoff, Andre, The Prophage and I, pp. 88-99, in Phage and the Origins of Molecular Biology, J. Cairns, G.S. Stent, and J.D. Watson eds., Cold Spring Harbor Laboratory Press, 1966.

(8) Wollman, Elie L, Bacterial Conjugation, pp. 216-225, in Phage and the Origins of Molecular Biology, J. Cairns, G.S. Stent, and J.D. Watson eds., Cold Spring Harbor Laboratory Press, 1966.

(9) “The Phage in the Letter,” Posted on the blog November 4, 2013.

(9) Francois Jacob, Nobel Lecture, December 11, 1965.

(11) Norkin, Leonard C., Virology: Molecular Biology and Pathogenesis, ASM Press, 2010.

Andre Lwoff