Allan McCulloch Campbell, the Barbara Kimball Browning Professor in the School of Humanities and Sciences, Emeritus, at Stanford and one of the world’s foremost experts on bacterial viruses, died on April 19 in Palo Alto. He was 88.

Allan McCulloch Campbell

Allan McCulloch Campbell (Image credit: Courtesy Stanford News Service)

Campbell was best known for describing how some viruses create genetic sleeper agents inside bacteria that remain dormant, sometimes for generations, awaiting a vulnerable moment when they can awaken and kill their hosts.

The existence of latent viruses that can be transmitted from one generation to the next without external reinfection had been suspected since the 1920s, but it wasn’t until Campbell’s work in the 1960s that scientists understood the mechanism by which this happened.

The Campbell model

While at the University of Rochester in New York, Campbell hypothesized that under certain conditions, a particular virus that can attack and kill bacteria did so by inserting its genes into the DNA of its host, the bacteria E. coli.

This hypothesis became known as the “Campbell model” and was eventually confirmed by Campbell and others. Their research showed that upon entering the bacterial cell, the virus, called phage lambda, snips the host’s circular chromosome and braids its own DNA into the dangling ends. Once safely ensconced, the virus lies low until the host weakens or stops growing, at which point it awakens and spawns virus particles that dissolve, or “lyse,” the bacterial cell.

The Campbell model helped pave the way for tools that today are mainstays of biological research, such as replicating segments of DNA and inserting them into chromosomes of other organisms.

“His model for the integration and excision of lambda is in genetics textbooks and was an important part of the education of one learning about recombination of plasmids” – small, circular, independently replicating DNA molecules – “and viruses with chromosomes, as I did in graduate school in the 1980s,” said Tim Stearns, the Frank Lee and Carol Hall Professor of Genetics and the chair of the biology department.

Insightful scientist

When he joined Stanford in 1968, Campbell continued his research focus on phage lambda, working to clarify the molecular details of how the virus inserted and removed its genes from the bacterial host. In both his phage research and in related work characterizing how E. coli synthesizes biotin – a B-vitamin essential to life – Campbell worked with his long-time collaborator and wife, Alice del Campillo Campbell.

Campbell’s daughter, Wendy Nelson, said that growing up with parents who were both scientists taught her and her brother to engage in critical thinking early on. “They both valued education and taught us to ask a lot of questions and to be curious,” Nelson said.

Campbell’s colleagues remember him as a brilliant scientist who had a gentle and unfailingly polite demeanor. “Allan attended essentially all of the departmental seminars, he listened closely, and then would almost always raise his hand ‘tentatively’ when the question period began,” recalled Philip Hanawalt, the Dr. Morris Herzstein Professor in Biology, Emeritus.

“He would then offer the most insightful – and sometimes devastating – question, but he would deliver it with utmost courtesy and sensitivity,” Hanawalt said. “I always asked Allan to be a member of the graduate thesis advisory committees for my students, because he would be incisive in his criticism of their work but he would deliver his evaluations so gently that they would never feel intimidated or threatened by them.”

Sharon Long, the William C. Steere, Jr. – Pfizer Inc. Professor in Biological Sciences,  called Campbell a “scholar’s scholar” for his integrity, thoroughness and clarity. “Every week he would spend a day in the library reading the newly arrived issues for a broad range of journals,” Long said. “In the days before internet searches, a five-minute conversation with Allan was often all you needed to know exactly where to go to find a needed research paper.”

Campbell’s wide-ranging intellect made him an invaluable resource within his department, said Robert Simoni, the Donald Kennedy Chair in the School of Humanities and Sciences and a professor emritus of biology. “He was a terrific and helpful sounding board for research topics quite distant from his own research,” Simoni said.

Campbell’s son, Joseph Campbell, remembers once suggesting to his father that he pursue “trendier” science topics that had more research grants available. “His response to me was, ‘I worked very hard all my life so that I can work on whatever I thought was interesting, not what the world thought was interesting, so that’s what I intend to do.’”

Donald Court, a former graduate student and postdoctoral researcher, said Campbell helped guide his career. “He never told me directly what to do but through discussions and advice made sure that I developed my own ideas and path in research,” said Court, who is now a senior investigator at the National Institutes of Health.

A career in science

Campbell was born on April 27, 1929 in Berkeley, California. Despite an obvious early talent in mathematics, Campbell chose to pursue laboratory research. “I … felt that experimental science kept me in touch with reality, whereas mathematics invited me to dwell within a dream world of abstractions,” he wrote in a personal history that was published in the Annual Review of Genetics.

Campbell enjoyed gardening, hiking, attending the opera with his wife and traveling. He kept in shape by taking brisk, rambling walks around campus and, until a few years ago, bicycling to work every day. One of his annual traditions was to bike to Stanford football games with his children. “He wasn’t a big sports person,” Nelson said, “He just thought it was a nice traditional thing to do.”

Campbell earned his bachelor’s degree in chemistry at the University of California, Berkeley, and master’s and doctoral degrees from the University of Illinois. He was a member of the National Academy of Sciences and a fellow of the American Academy of Microbiology, the American Association for the Advancement of Science and the American Academy of Arts and Sciences. For his accomplishments, he also received the Abbott ASM Lifetime Achievement Award from the American Society of Microbiology in 2004.

Campbell is survived by his wife of 59 years, Alice del Campillo Campbell; his two children, Joseph Campbell and Wendy Nelson; and his five grandchildren, Andrew, Eli, and Ray Nelson, and Theodore and Grace Campbell.

A memorial service is planned for the summer.