ABOVE: Aequorea victoria, the species of jellyfish Osamu Shimomura used to isolate green fluorescent protein.

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For a complete list of our obituaries, see here.

NASA

Renowned by the scientific community for his research on black holes and relativity and beloved by the public for his guest appearances on The Simpsons and The Big Bang Theory, Stephen Hawking died in March at the age of 76. While working on his PhD in 1963 at Cambridge University, he was diagnosed with amyotrophic lateral sclerosis and given two years to live. It was an active mind and a sense of humor, he said in 2013 documentary called Hawking, that kept him alive another five decades.

Having ALS may have actually heightened Hawking’s mental prowess, Kip Thorne, a physicist at Caltech who frequently collaborated with Hawking, told NPR. “It was because of this handicap that he developed new ways of thinking,” Thorne said, “new ways of wrapping his brain around things that enabled him to out-think anybody else in the field.”

Hawking “left an intellectual vacuum in his wake,” astrophysicist Neil deGrasse Tyson wrote on Twitter the day the physicist died. “But it’s not empty. Think of it as a kind of vacuum energy permeating the fabric of spacetime that defies measure.”

UI NEWS BUREAU

Longtime estrogen researcher Ann Nardulli died in June of cancer. She was 69.

Nardulli earned her master’s degree and PhD from the University of Illinois in the lab of endocrinologist Benita Katzenellenbogen and then stayed at the university for the rest of her career, first as a postdoc and then as a professor in the Department of Molecular and Integrative Physiology.

“Dr. Nardulli did pioneering work that identified the protein complexes with which the estrogen receptor associated, many previously unknown, and she and her laboratory associates went on to elucidate how these proteins collaborated with and modulated the activities of the estrogen receptor in breast cancer cells and tumors,” Katzenellenbogen wrote in an email to The Scientist.

In recent years, her research has focused on estrogen’s effect on the brain. “Her legacy really isn’t over yet,” Bonnie Zeigler, a research associate for 16 years in Nardulli’s lab and a coauthor on numerous papers, told The Scientist. Zeigler said several papers the lab had been working on are either submitted or being written up.

Zeigler said she and Nardulli were like “scientific sisters,” and credits Nardulli with giving a lot of “trust and opportunity.”

Nobel Prize winner Aaron Klug, who developed crystallographic electron microscopy and determined the biological structures of nucleic acid, passed away in November. He was 92.

After finishing his PhD in solid state physics at the University of Cambridge in 1952, Klug worked with X-ray crystallographer Rosalind Franklin at Birkbeck College, University of London, where he was introduced to the problem of visualizing nucleoprotein complexes. He eventually figured out how to translate 2-D electron micrographs of the complexes in to 3-D structures. The process came to be called crystallographic electron microscopy.

“Klug was a towering giant of 20th century molecular biology,” Venki Ramakrishnan, president of Britain’s Royal Society, said in a statement. He “made fundamental contributions to the development of methods to decipher and thus understand complex biological structures.”

SALK INSTITUTE

Pioneering immunologist Melvin Cohn died in October. He was 96. Cohn cofounded the Salk Institute for Biological Studies, and there he studied the evolutionary selection pressures that shape the immune system, showed how immune cells and antibodies respond directly to infection and pathogen exposure, and made computer models to predict immune system behavior.

Before Jonas Salk personally invited Cohn to join the institute in 1961, Cohn served in the military, studying the after effects of dropping the atomic bomb on Hiroshima. He also researched gene activity with French biochemist Jacques Monod, who won the Nobel Prize in 1965 for the work. Cohn held positions at Washington University School of Medicine in St. Louis and then Stanford University, where he caught Salk’s attention.

“Mel helped to make Salk what it is today,” Suzanne Bourgeois-Cohn, Cohn’s wife and fellow Salk scientist, said in a statement. “I and his many friends will miss him terribly.”

NORTHWESTERN UNIVERSITY

Founder of the American Women in Science, Neena Schwartz died in April at the age of 91. Schwartz was an endocrinologist at Northwestern University and discovered the hormone inhibin, Through further studies she reveals its role in regulating reproductive cycles.

Schwartz “was a tremendous scientist, a pioneer for women in the sciences, and a leader in our discipline of endocrinology,” Teresa Woodruff and Kelly Mayo, both of Northwestern University, wrote in a memorial in Endocrine News.

Early in her career, Schwartz studied rats’ hormonal cycles, uncovering the basic mechanics of the hypothalamic-pituitary-gonadal crosstalk of hormones that controls reproduction. She then described inhibin, which leads to a drop in follicle stimulating hormone. “I’ve never seen a result that was clearer. So there was an inhibin in this follicle fluid,” Schwartz said in a 2008 interview. “Not only was it important to demonstrate what was going on in the cycle, but the fluid gave gallons of material from which people could isolate the inhibin. So the biochemists and the molecular biologists jumped in and were able to isolate the inhibin within a few years.”

Schwartz also championed women in science and wrote a book, A Lab of My Own, talking about feminism in science. She also eventually opened up about being gay and told BoingBoing in 2010 that “in science, you work in unusually close quarters with other people, and you don’t talk much about your personal life. But if nobody asks you, and you never tell, your sexuality becomes like this elephant in the room.” She said support was “astounding” after she came out.

In April, psychiatrist Beatrix Hamburg died from Alzheimer’s disease. She was 94. Hamburg was an expert on school violence and championed the idea of peer counseling, in which peer groups offer guidance to teens instead of authority figures.

“She became one of the nation’s leading experts on the problems of adolescence and different stages of adolescence . . . during an era in which most people simply didn’t really think about them in any particular way or fashion,” Jack Barchas, chairman of Weill Cornell Medical College’s psychiatry department, said in a 2015 video that announced a humanitarian prize awarded to Hamburg and her husband, psychiatrist David Hamburg.

Hamburg also was concerned with young adults’ stress levels. “She was truly a pioneer in understanding the importance of stress in the lives of children very early on before we appreciated how long-lasting the effects of trauma are in early life and adolescence,” Huda Akil, a ­codirector and senior research professor at the Molecular & Behavioral Neuroscience Institute at the University of Michigan, told The Washington Post.

TOM KLEINDINST

Green fluorescent protein discoverer Osamu Shimomura died in October at the age of 90.

Shimomura and his wife Akemi Shimomura, a research assistant, were working at Princeton University when they isolated green fluorescent protein (GFP) from 10,000 jellyfish they collected in Washington state’s Puget Sound. Shimomura later joined the Marine Biological Laboratory (MBL) in Woods Hole, Massachusetts.

“The development of GFP to visualize the inner workings of cells, organs, and entire organisms precipitated a golden age of innovation in microscopy and imaging that continues to unfold,” Nipam Patel, director of the Marine Biological Laboratory, where Shimomura worked from 1982 until he retired in 2001, said in a statement. “The importance of Dr. Shimomura’s contribution to contemporary biological discovery cannot be overstated.”

NYU LANGONE HEALTH

Microbiologist and pathologist Ruth Nussenzweig, who led the fight against malaria, died in April at the age of 89.

Nussenzweig’s work led to the first malaria vaccine approved by the World Health Organization for use in Africa, according to the The New York Times. Over her career, she published more than 200 scientific papers, with her latest on vaccines against Plasmodium vivax appearing in January in Scientific Reports.

“Her work in the field of immunology serves as a guide for the development of a new generation of recombinant vaccines,” Maurício Martins Rodrigues told Agência FAPESP in 2013.

Nobel Prize winner Thomas Steitz, who used X-ray crystallography to determine the atomic structure of the ribosome, died of pancreatic cancer in October. He was 78.

After a PhD at Harvard University, where Steitz met his wife Joan, he did a postdoc at the MRC Laboratory of Molecular Biology in Cambridge, England, working with Nobel Prize winners Max Perutz and John Cowdery Kendrew, who won for their X-ray crystallography of proteins. MRC was famous for its canteen, where scientists spent much of their time discussing experiments. “Initially I wondered how anyone got any experiments done since they were spending so much time in the canteen, and then I realized that the many discussions reduced the number of unwise or unnecessary experiments that were done and enhanced the good ones,” Steitz wrote in his Nobel biography.

Once Steitz finished his postdoc in 1970, both he and his wife were looking for academic positions. They ended up at Yale University, where both were given assistant professor positions—that was in contrast to the University of California, Berkeley, where Joan was offered only a research associate, according to The New York Times. “I was very, very lucky to have married Tom,” Joan Steitz told The Times. “He really believed I should have as equal an opportunity to succeed as he.”

And both did. In 2000, Tom Steitz developed the atomic picture of the ribosome, earning him a shared Nobel in Chemistry in 2009. In September 2018, a few weeks before Tom passed away, Joan Steitz won the Lasker special achievement award.

Together, they were considered “one of the great power couples of science,” according to the Hartford-Courant.

TOM ZUBACK

Mathilde Krim, a founding chairwoman of amfAR, the Foundation for AIDS Research, died last January at the age of 91.

“She saw that AIDS would demand the intellectual resources of the fields of medicine, basic science and public health, and she set out to bring them to amfAR to guide its research grantmaking, overturning many stereotypical notions of gay men in the process,” the late Allan Rosenfield, former dean of the Mailman School and a member of amfAR’s Board of Trustees, wrote about Krim, according to an obituary published by amfAR.

As AIDS was emerging in the early 1980s, Krim foresaw the ability of the illness to reach epidemic levels and drove research efforts to better understand it underlying cause. She founded the AIDS Medical Foundation, which later merged with the National AIDS Research Foundation and was renamed amfAR.

“My greatest AIDS hero has died,” Peter Staley, a gay rights activist and veteran of the activist group ACT UP, tweeted after hearing of Krim’s death. He added that she was a “warrior against homophobia & AIDS-related stigma, defender of science & public health, and mother-figure to countless activists.”

THE ROCKEFELLER UNIVERSITY

Biologist Günter Blobel, who determined how cells organize the trafficking of proteins between intracellular compartments, died in February of cancer at the age of 81.

“Günter was a towering figure in the scientific community who made fundamental contributions to our understanding of the most basic processes that underlie life on our planet,” Richard Lifton, president of The Rockefeller University, said in a statement. “His work revolutionized cell biology, demonstrating that seemingly impenetrable problems could be understood in molecular detail.”

In 1971, Blobel and David Sabatini started to lay the foundation for the signal hypothesis of protein organization. Then, Blobel and others confirmed the idea, showing that certain amino acid sequences direct a particular protein to a specific target organelle. That, it turns out, is important for molecular trafficking, but when the system breaks down, it can contribute to disease.

Blobel’s “loss will be felt deeply at Rockefeller and throughout the scientific community, where he was revered for his passion for science, personal generosity and inspired leadership,” Lifton said.

UC DAVIS

In April, marine biologist Susan Williams was killed in a six-vehicle car crash. She was 66.

“What a loss for our country and our oceans and everybody that has ever met her,” Lynn Woolsey, former US House Representative (D-CA), told The Press Democrat. “She was able to put words to science and make it real.” She noted that Williams’s ability to communicate science was essential for California lawmakers, who turned to her for advice as they worked to craft legislation that protected the environment.

Williams was the former director of the University of California, Davis, Bodega Marine Laboratory. Her work focused on conserving the world’s oceans and her experiments revealed that seagrass could store carbon dioxide, helping to restore damaged ocean habitats.

“She was among the most renowned marine ecologists in the U.S. and the world,” Gary Cherr, who succeeded Williams as director of the Bodega Marine Laboratory, said in a statement. “She was somebody who has been tremendously impactful in terms of research—restoring habitats in degraded environments—and impacting state and national policy.”

Coleader of the Human Genome Project, John Sulston died in March at age 75. He was in charge of the UK-based team of the project and championed open access to the project’s data. Prior to working on sequencing the human genome, he traced how each cell in C. elegans developed—an effort that won him a Nobel Prize in 2002.

Around that time, Sulston was working on the Human Genome Project with his colleagues at what is now the Wellcome Trust Sanger Institute. There, his group sequenced and submitted about a one-third of the human genome to the project, with the rest coming from the US National Institutes of Health and the US Department of Energy. While working on the project, he encouraged open access to all genomic data, from human to nematode and beyond.

Sulston’s “dedication to free access to scientific information was the basis of the open access movement, and helped ensure that the reference human genome sequence was published openly for the benefit of all humanity,” Jeremy Farrar, director of the Wellcome Trust, said in a statement. “It’s just one of the ways that John’s approach set the standard for researchers everywhere.”

Five months after being diagnosed with brain cancer, marine biologist Ruth Gates died of the disease at the age of 56.

Gates started her own lab at the University of Hawaii in 2003 and not long after showed, through genetic studies, that algae living on coral were complex species. These algae “used to just be green balls,” Peter Edmunds, a coral scientist at California State University and a friend of Gates, told The Atlantic. “But Ruth showed us that, oh my god, these things are so much more diverse than we thought.”

Her research revealed a connection between a warming climate and coral bleaching events, and, at the time of her death, she and colleague Madeleine van Oppen of the Australian Institute of Marine Science were using that information to selectively breed corals to better tolerate climate change and other stressors.

“Ruth was not only a shining star in coral research, but an indomitable spirit in every aspect of life,” Hawaii Institute of Marine Biology researcher Judy Lemus, a friend and colleague of Gates, said in a statement. “Her enthusiasm was contagious, and she absolutely loved what she did. Her loss will be felt deeply within our own community and throughout the broader research community.”

COURTESY OF THE SEYFARTH-CHENEY FAMILY

Social cognition pioneer Dorothy Cheney died of breast cancer in November at the age of 68.

Cheney was perhaps best known for developing strict experimental precision for study animals in the wild. Cheney and Robert Seyfarth, her husband and research partner, “really pushed the limit [of scientific rigor] and established that as the new standard for doing field biology,” says Marc Schmidt, a biology professor at University of Pennsylvania, where Cheney was a professor. The couple, he said, shifted the disciple from being focused on observation to using experimentation, which included playing recorded alarm calls in the wild and other innovative techniques.

The duo’s methods revealed, for example, that monkeys in Amboseli National Park in Kenya could distinguish predators in their alarm calls. “They’re not just gasping when they see a predator,” Jacinta Beehner, an associate professor at the University of Michigan and a former postdoc of Cheney, told The Scientist. “They’re saying, ‘leopard!’ They’re saying, ‘snake!’ They’re saying, ‘raptor!’”

Their work also revealed that animals understand their rank and the social hierarchy of others in their group. “It’s considered to be a precursor to language, where you can organize information in a hierarchical structure,” said Beehner, who worked on this project.

AARHUS UNIVERSITY

Jens Christian Skou, who discovered the sodium-potassium pump in cell membranes, died in May at age 99.

Skou started his career in surgery, earning his medical degree from the University of Copenhagen in 1944. But as he performed operation after operation, he became increasingly interested in how anesthetics worked on the body, and, in 1947, enrolled as a graduate student at Aarhus University to research the topic. “I got so interested in doing scientific work that I decided to continue and give up surgery,” Skou wrote in his autobiography for the Nobel Prize, which he won in 1997.

As Skou studied anesthetics, he discovered that an enzyme could transport ions across the cell membrane—the sodium-potassium pump. At first, not everyone believed him, saying he was “talking nonsense,” he said in 2008, according to an obituary on Aarhus University’s website. But the idea eventually took hold, helping to explain essential features of cell physiology, including how nerve cells send and receive signals.

Skou was also an advocate for research funding. “His tireless struggle to tell politicians and the outside world about the importance of non-targeted funding for research has had a huge impact on the research environment,” Lars Bo Nielsen, dean of the Faculty of Health at Aarhus University, where Skou was professor emeritus, says in a statement. “He has been a cornerstone and a beacon for research, and there are a great many people who are deeply grateful for his efforts.”