Nobels note neutrinos, DNA, drugs

Work on particle masses, gene repair, fighting disease honored

dna ligase

Specialized proteins (blue and yellow) can repair damaged DNA. The 2015 Nobel Prize in chemistry was awarded to three researchers who determined how the cell works to protect genetic material in the face of environmental damages or DNA-copying errors.

Courtesy of Tom Ellenberger/Washington Univ. School of Medicine, via NIGMS

The Nobel Prizes in physics, chemistry and physiology or medicine ran the gamut this year, honoring both fundamental science discoveries and research with real-world impacts.

The physiology or medicine award went to three researchers who developed life-saving drugs. William Campbell of Drew University in Madison, N.J., and Satoshi Ōmura of Kitasato University in Tokyo won half the prize for their work on ivermectin, which combats roundworm infections. The other half went to Youyou Tu of the China Academy of Chinese Medical Sciences for her discovery of the antimalarial drug artemisinin.

“This is one of those Nobel Prizes for drugs that have truly impacted hundreds of millions of people, no exaggeration,” says Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases in Bethesda, Md.

In 1974, Ōmura discovered in the vicinity of a Japanese golf course a soil bacterium called Streptomyces avermitilis that makes a compound called avermectin. Campbell determined that the compound can kill some parasites’ larvae. Avermectin was later tweaked to make ivermectin, an even more powerful compound that has helped eliminate river blindness in parts of Latin America and that treats debilitating elephantiasis.

In 1967, Tu and colleagues began combing through over 2,000 traditional Chinese herbal recipes and eventually found a compound in the sweet wormwood plant (Artemisia annua) that showed promise against malaria caused by Plasmodium parasites. After seeing artemisinin combat parasites in mice and monkeys, Tu tested it on herself.

Discoveries honored by this year’s chemistry prize also have implications for health. Tomas Lindahl, Paul Modrich and Aziz Sancar identified molecular repair kits that cells use to fix damaged DNA. Without a way to correct DNA errors, damage would build up and trigger diseases such as cancer.

Understanding the details of DNA repair has been important for designing cancer drugs, says Laurence Pearl, a biochemist and structural biologist at the University of Sussex in England.

DNA is a fragile molecule that can be damaged by sunlight, toxic chemicals, radiation or even normal chemical reactions inside the cell. Lindahl, of the Francis Crick Institute in England, determined that DNA can fall apart on its own, even without injury. He described how a cell can remove and replace damaged DNA constituents.

Sometimes the cell makes mistakes while copying DNA. Modrich’s work revealed how a cell can correct these genetic errors by replacing DNA’s individual units. Modrich is a Howard Hughes Medical Institute investigator at the Duke University School of Medicine.

Sancar, of the University of North Carolina School of Medicine, uncovered some of the proteins responsible for patching up DNA after ultraviolet damage and how they work.

Capturing the identity-shifting behavior of neutrinos won Takaaki Kajita of the University of Tokyo and Arthur McDonald of Queen’s University in Kingston, Canada, the physics prize. The scientists led giant underground experiments that revealed that the elusive particles morph from one variety into another.

Those findings demonstrated that neutrinos have mass, which confirmed many physicists’ suspicions but defies the standard model, the framework that predicts the properties of nature’s particles and forces.

Physicists knew that three types of neutrinos exist in nature: electron, muon and tau. In 1998, Kajita and his team at the Super-Kamiokande experiment found evidence that neutrinos produced in Earth’s atmosphere switched identities before striking the detector, located under a Japanese mountain. Three years later, McDonald’s Sudbury Neutrino Observatory collaboration discovered that some neutrinos emitted by the sun change type en route to Earth.

— Andrew Grant, Meghan Rosen, Tina Hesman Saey, Laura Sanders, Sarah Schwartz and Thomas Sumner

Read more in-depth coverage in our Nobels 2015 Editor’s Pick

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