Worlds In Collision

Two terrestrial planets orbiting a mature sun-like star some 300 light-years from Earth recently suffered a violent collision, astronomers at UCLA, Tennessee State University (TSU) and the California Institute of Technology will report in a December issue of the Astrophysical Journal.

"It's as if Earth and Venus collided with each other," says Benjamin Zuckerman, UCLA professor of physics and astronomy and a co-author on the paper. "Astronomers have never seen anything like this before. Apparently, major catastrophic collisions can take place in a fully mature planetary system."

"If any life was present on either planet, the massive collision would have wiped out everything in a matter of minutes — the ultimate extinction event," says co-author Gregory Henry, an astronomer at TSU. "A massive disk of infrared-emitting dust circling the star provides silent testimony to this sad fate."

Zuckerman, Henry and Michael Muno, an astronomer at Caltech at the time of the research, were studying a star known as BD+20 307, which is surrounded by a shocking 1 million times more dust than is orbiting our sun. The star is located in the constellation Aries. The astronomers gathered X-ray data using the orbiting Chandra X-ray Observatory and brightness data from one of TSU's automated telescopes in southern Arizona, hoping to measure the age of the star.

"We expected to find that BD+20 307 was relatively young, a few hundred million years old at most, with the massive dust ring signaling the final stages in the formation of the star's planetary system," Muno says.

Those expectations were shown to be premature, however, when Carnegie Institution of Washington astronomer Alycia Weinberger announced in the May 20, issue of the Astrophysical Journal that BD+20 307 is actually a close binary star — two stars orbiting around their common center of mass.

"That discovery radically revised the interpretation of the data and transformed the star into a unique and intriguing system," says TSU astronomer Francis Fekel who, along with TSU's Michael Williamson, was asked to provide additional spectroscopic data from another TSU automated telescope in Arizona to assist in comprehending this exceptional binary system.

The new spectroscopic data confirmed that BD+20 307 is composed of two stars, both very similar in mass, temperature and size to our own sun. They orbit about their common center of mass every 3.42 days.

"The patterns of element abundances in the stars show that they are much older than a few hundred million years, as originally thought," Fekel says. "Instead, the binary system appears to have an age of several billion years, comparable to our solar system."

"The planetary collision in BD+20 307 was not observed directly but rather was inferred from the extraordinary quantity of dust particles that orbit the binary pair at about the same distance as Earth and Venus are from our sun," Henry says. "If this dust does indeed point to the presence of terrestrial planets, then this represents the first known example of planets of any mass in orbit around a close binary star."

Zuckerman and colleagues first reported in the journal Nature in July 2005 that BD+20 307, then still thought to be a single star, was surrounded by more warm orbiting dust than any other sun-like star known to astronomers. The dust is orbiting the binary system very closely, where Earth-like planets are most likely to be and where dust typically cannot survive long. Small dust particles get pushed away by stellar radiation, while larger pieces get reduced to dust in collisions within the disk and are then whisked away. Thus, the dust-forming collision near BD+20 307 must have taken place rather recently, probably within the past few hundred thousand years and perhaps much more recently, the astronomers said.

"This poses two very interesting questions," Fekel says. "How do planetary orbits become destabilized in such an old, mature system, and could such a collision happen in our own solar system?"

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Study Reveals Strongest Predictors for Oscar Nominations

If you're an actor angling for an Academy Award nomination on Tuesday, you better hope you didn't leave the audience rolling in the aisles, suggests a new study from UCLA's California Center for Population Research.

"The odds of being nominated for an Academy Award are so much greater for performers who appear in dramas that — at least this time of year — it really pays to be a drama queen," says Gabriel Rossman, one of the study's two authors and an assistant professor of sociology at UCLA.

Albeit to a lesser degree, it also helps to have a major film distributor, prior Oscar nominations, a high spot in the pecking order in past movie credits, fewer films competing for attention and good collaborators. And it doesn't hurt to be a woman.

"A performer's odds of being nominated are largely set before the cameras even start rolling, back when the script was bought, the director was signed and the film was cast," says Nicole Esparza, the study's lead author and a Robert Wood Johnson Scholar in Health Policy Research at Harvard University. "It's surprising how many variables other than a performer's talent play a role in determining who gets nominated."

The 80th Academy Awards nominations are scheduled to be announced at 5:30 a.m. on Tuesday at the Academy's Samuel Goldwyn Theater in Beverly Hills.

Using Internet Movie Database (IMDb) records for every Oscar-eligible film made between the founding of the Academy of Motion Pictures Arts and Sciences in 1927 and 2005, Esparza and Rossman looked for conditions that improved the odds of a performer getting the nod.

The researchers looked at number of Oscar-eligible films in any given year, the distributors and studios behind each performer's films, the film's tone or subject matter, the cast size, the sex of the performer, the performer's contacts within the industry, and past Oscar nominations among a film's cast, directors and writers.

The single greatest predictor of a nomination proved to be serious subject matter — or at least a film that was classified by IMDb as a drama, despite the possible presence of comedic elements. In examining IMDb records on 171,539 performances by 39,518 actors in 19,351 Oscar-eligible films, the researchers found that actors were nine times more likely to receive a nomination for their work in a drama than in a non-drama.

"In the entertainment industry, there's long been a sense that the nomination process prefers dramas, but I don't think anybody is aware of the magnitude of the effect," Rossman says.

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Plants With More Vitamin C May Result From University Discovery

UCLA and Dartmouth scientists have identified a crucial enzyme in plant vitamin C synthesis, which could lead to enhanced crops. The discovery now makes clear the entire 10-step process by which plants convert glucose into vitamin C, an important antioxidant in nature.

"If we can find ways to enhance the activity of this enzyme, it may be possible to engineer plants to make more vitamin C and produce better crops," says Steven Clarke, UCLA professor of chemistry and biochemistry, director of UCLA's Molecular Biology Institute and co-author of the research study, to be published as a 'Paper of the Week' in the Journal of Biological Chemistry and currently available online.

"We hit on gold," Clarke says, "because we now have a chance to improve human nutrition and to increase the resistance of plants to oxidative stress. Plants may grow better with more vitamin C, especially with more ozone in the atmosphere due to pollution."

Carole Linster, a UCLA postdoctoral fellow in chemistry and biochemistry and lead author of the study, discovered the controlling enzyme, GDP-L-galactose phosphorylase, which serves as the biosynthetic pathway by which plants manufacture vitamin C.

"Our finding leads to attractive approaches for increasing the vitamin C content in plants," Linster says. "We now have two strategies to provide enhanced protection against oxidative damage: Stimulate the endogenous activity of the identified enzyme or engineer transgenic plants which overexpress the gene that encodes the enzyme."

When life on Earth began, there was almost no oxygen, Clarke notes.

"Two billion years ago, plants devised an efficient way to get sunlight to make sugar from carbon dioxide that produced oxygen as a waste product; that waste product probably killed off most of all living species at that time," Clarke says. "The only organisms that survived developed defenses against it, and one of the best defenses is vitamin C. Plants learned how to make vitamin C to protect themselves."

Prior to the new research, vitamin C may have been the most important small molecule whose biosynthetic pathway remained a mystery.

An essential vitamin for humans, vitamin C is also an important antioxidant for animals and plants. Humans do not have the ability to make vitamin C and get it from dietary sources, especially from plants. It was not until 1998 that a biosynthetic pathway was proposed to explain how plants make this compound. Research confirmed much of the pathway, although one crucial missing link continued to baffle scientists and remained unknown until this new research.

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Googling Brain Proteins With 3-D Goggles

The Allen Brain Atlas, a genome-wide map of the mouse brain on the Internet, has been hailed as "Google of the brain." The atlas now has a companion of the brain's working molecules, a sort of pop-up book of the proteins, or proteome map, that those genes express.

The protein map is "the first to apply quantitative proteomics to imaging," says Richard Smith, Battelle fellow at the US Department of Energy's Pacific Northwest National Laboratory, who led the mapping effort with Desmond Smith of UCLA's David Geffen School of Medicine.
"Proteins are the lead actors, the most important part of the picture," PNNL's Smith says. "They are the molecules that do the work of the cells."

Fine-tuning such proteome maps will enable comparisons of healthy brains with others whose protein portraits look different. Contrasts in location and abundance of proteins may display the earliest detectable stages of Alzheimer's, Parkinson's and other neurological diseases. They hope such diseases might be curbed if caught and treated early enough.

The National Institutes of Health-funded study, performed at DOE's Environmental Molecular Sciences Laboratory on PNNL's campus, is published in the advance online edition of Genome Research and featured in current Nature online Neuroscience Gateway.

To produce the map, the team characterized center-brain slices as scores of 1 millimeter cubes, or "voxels," to "show us where proteins appear in the brain and where they vary in abundance," PNNL's Smith says. "We labeled all the proteins so we would have reference points so we know we're looking at the same protein between different parts of the brain and from one mouse to another."

Until now, proteomics, which enlists a specially modified instrument called a mass spectrometer for the task of identifying proteins and tallying them, has been akin to flying blind over a lake of proteins. The abundance and protein type could be discerned from a given sample, but "knowing their location and how the abundances change in different cases is important for understanding what they do," PNNL's Smith says.

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