Three AAAS members are among the winners of this year’s scientific Nobel Prizes, honored for groundbreaking research in physics and medicine.
Saul Perlmutter, head of the Supernova Cosmology Project at the Lawrence Berkley National Laboratory at the University of California, Berkeley, received one half of the 2011 Nobel Prize for research suggesting that the expansion of the universe is accelerating rather than slowing down. He shares the prize with Brian Schmidt of the Australian National University and Adam Riess of Johns Hopkins University and the Space Telescope Science Institute.
AAAS members Jules Hoffmann of University of Strasbourg and the late Ralph Steinman of Rockefeller University shared the 2011 Nobel Prize in Physiology or Medicine with Bruce Beutler of the Scripps Research Institute. Hoffmann and Beutler were recognized for their work showing how the human innate immune system first responds to invading microbes. Steinman was honored for his discovery of immune dendritic cells, which activate later stages of the immune response.
Steinman died on 30 September from pancreatic cancer, a disease he sought to treat with experimental therapies that drew from his own research. Although prizes are not given to deceased researchers, the Nobel Assembly was not aware of Steinman’s death until 3 October. In a statement released after the award announcement, the Assembly said Steinman would remain a 2011 Nobel laureate.
Steinman discovered the dendritic cell in 1973. In further experiments, he confirmed that these cells play a key role in the body’s adaptive immune system, which consists of highly specialized cells with the memory to fight off specific pathogens. Steinman showed that dendritic cells activate T cells in the adaptive immune system, helping the T cells to zero in on particular microbes.
Hoffman’s prize-winning research focused on the body’s first line of immune defense, often called the innate immune system. In fruit fly experiments published in 1996, he and his colleagues revealed the importance of the Toll gene, which protected the flies from bacterial and fungal infections. Subsequent research by Hoffmann, Beutler and other have since uncovered numerous Toll-like genes that activate the innate immune system against microorganisms. Beutler published some of this work in mice in the journal Science just two years after Hoffmann’s initial Toll discoveries.
Perlmutter led one of two teams who in 1996 studied a type of exploded star called type Ia supernovae to learn more about the universe’s expansion since the Big Bang. By measuring the brightness and wavelength of the light from these supernovae, the research teams determined that the universe’s expansion was speeding up—contrary to a popular belief that the gravitational pull of the galaxies should be putting the brakes on expansion. The discoveries by Perlmutter, Schmidt, and Riess soon led to explorations of the role that “dark matter” might play in driving this mysterious acceleration.
The 2011 Nobel Prize in Chemistry was awarded to Dan Schectman of the Technion-Israel Institute of Technology for his discovery of quasicrystals—crystals with a regular but non-repeating pattern. Scientists had considered such crystals mathematically impossible, and Schectman’s work was widely dismissed by his colleagues. But his discovery was eventually confirmed in other laboratory experiments, and in 2009 Science published a report found in minerals unearthed in the Koryak Mountains in Russia.