Study to look at molecules from Earth found in space
Many of the organic molecules that make up life on Earth also have been found in space. A U-M astronomer will use the Herschel Space Observatory to study these chemical compounds in new detail in the warm clouds of gas and dust around young stars.
They hope to gain insights into how organic molecules form in space, and possibly, how life formed on Earth.
“The chemistry of space makes molecules that are the precursors of life. It’s possible that the Earth didn’t have to make these things on its own, but that they were provided from space,” says Ted Bergin, an associate professor in the Department of Astronomy.
Bergin is a co-investigator on the Heterodyne Instrument for the Infrared aboard Herschel and a principal investigator on one of its key observing programs.
Herschel, a European Space Agency mission with NASA participation, is scheduled to launch Wednesday. An orbiting telescope that will unlock new wavelengths on the electromagnetic spectrum, it will allow astronomers to observe at the far-infrared wavelengths where organic molecules and water emit their chemical signatures.
Meteorites flecked with amino acids, which make proteins, have fallen to Earth from space. In faraway galaxies and stellar nurseries, astronomers have detected complex organic sugar and hydrocarbon molecules that are key components in RNA and chlorophyll in plants. Bergin expects to detect tens if not hundreds of these kinds of compounds — some of which have never been found before outside the Earth.
He also is involved in a Herschel project to look for water molecules in space. Traces of water in warm clouds of gas and dust around young stars could hold clues to how water forms and behaves in space, and how this elixir of life came to be so abundant on Earth. Scientists believe water got to Earth in a similar way as organic molecules.
Boredom in marriage leads to long-term dissatisfaction
Boredom, not only conflicts, causes couples to lose interest in their marriage, new findings indicate.
Researchers at U-M and Stony Brook University interviewed 123 couples in their seventh year of marriage and again nine years later.
“These findings show directly, for the first time, that not only conflicts but also simple boredom with the relationship can shape relationships over the long term,” said Terri Orbuch, a research professor at the Institute for Social Research and Institute for Research on Women and Gender.
Orbuch collaborated on the new study, which is published in the journal Psychological Science, with lead author Irene Tsapelas and Arthur Aron of Stony Brook University.
Participants were asked, “During the past month, how often did you feel that your marriage was in a rut, or getting into a rut, that you do the same thing all the time and rarely get to do exciting things together as a couple?”
The study indicated that greater boredom in year seven predicted significantly less satisfaction at year 16. In addition, greater satisfaction in year seven did not significantly predict less boredom in year 16.
Being bored with the marriage undermines closeness, which in turn reduces satisfaction, Orbuch says.
Couples can reduce boredom by participating together in exciting activities. The closeness may lead to greater satisfaction, partner responsiveness, commitment and trust, the researchers said.
— By Jared Wadley, News Service
Nanomovies can provide high-definition look at RNA
Building on a technique they used to produce nanomovies of RNA molecules in motion, researchers have created “high definition” versions of the animations that reveal even more details about how RNA changes shape and binds with drug molecules.
The research, led by Hashim Al-Hashimi, associate professor of chemistry and biophysics, and Ioan Andricioaei of the University of California, Irvine, fuses two methods of gleaning atomic-level information about RNA. It lays the groundwork for a whole new approach to drug design, says Al-Hashimi.
The work is described in a paper published online this week in the journal Nucleic Acids Research.
Typically, RNA works by radically changing shape when bound to something else. The shape changes, in turn, trigger other processes or cascades of events.
Al-Hashimi’s earlier nanomovies showed how parts of the RNA molecule — which has ladder-like arms connected by a flexible hub or linker — twist, bend and rotate relative to one another.
Unlike animations produced from theoretical calculations — an approach known as molecular dynamics simulations — Al-Hashimi’s earlier nanomovies were based on actual NMR data and covered a much longer timescale than the simulations. However, there are limits to how much detail such nanomovies can reveal, Al-Hashimi says.
Movies produced with molecular dynamics simulations, on the other hand, provide better resolution. But because they’re based on theoretical calculations, it’s hard to know how closely they reflect reality, says Irvine’s Andricioaei.
By marrying the two techniques, Andricioaei, Al-Hashimi and co-workers were able to validate the simulations and combine them with NMR data to produce a “fully resolved, high-definition movie of what RNA does,” Al-Hashimi says.
In addition to Al-Hashimi and Andricioaei, joint first authors of the Nucleic Acids Research article are UC Irvine graduate student Aaron Frank and U-M graduate student Andrew Stelzer.
— Nancy Ross-Flanigan, News Service
Research indicates Native Americans descended from same source in Asia
U-M researchers and their colleagues have uncovered additional genetic evidence supporting the idea that the ancestors of Native Americans descend from the same source in Asia.
While other scientists have suggested there may have been multiple migratory waves with multiple origins, U-M population geneticist Noah Rosenberg said his team’s latest findings support the idea that “most Native Americans likely descend from the same founding population.”
The new evidence is detailed in the May edition of the journal Molecular Biology and Evolution, published by Oxford Journals. The paper’s first author is anthropologist Kari Schroeder of the University of California, Davis.
The team studied a genetic variant that’s common among Native Americans throughout North and South America but absent from all other human populations, except some inhabitants along the eastern edge of Siberia. The rare genetic variant, known as the 9-repeat allele at microsatellite D9S1120, has been found in all Native American populations sampled to date and was identified by Schroeder, Rosenberg and their colleagues two years ago.
Follow-up studies have now shown it’s highly unlikely that multiple founding populations settled the Americas. “What we’ve shown in this paper is that this variant has a single origin, which is evidence that all of the individuals who carry the variant have a single origin as well,” says Rosenberg, an assistant research professor at the Life Sciences Institute.
The latest studies also suggest that the founders lived apart from the ancestors of modern Asian populations for several thousand years before moving southward in the Americas.
— Jim Erickson, News Service
New brain imaging process helps assess likely survival
As early as one week after patients begin treatment for brain tumors, a new imaging analysis method is able to predict which patients would live longer, researchers from the Comprehensive Cancer Center have found.
The method uses a standard magnetic resonance imaging, or MRI, protocol to monitor changes over time in tumor blood volume within individual voxels of the image, rather than a composite view of average change within the tumor.
This parametric response map allowed researchers to see specific areas in which tumor blood volume increased or decreased, which may have canceled each other out when looking at the changes as an average.
Results of the study appear in the advance online edition of Nature Medicine.
“What we have potentially is a generalized analytical approach that we can use to quantify treatment intervention in patients,” says study author Brian Ross, professor of radiology and biological chemistry at the Medical School and co-director of the Molecular Imaging Program at the Comprehensive Cancer Center.
The researchers looked at 44 people with high-grade glioma, a type of brain tumor, who were treated with chemotherapy and radiation. Each participant underwent MRIs before treatment, and one week and three weeks after starting treatment. The researchers then looked at the relative cerebral blood volume and the relative cerebral blood flow of the tumor to analyze voxel-wise changes among the serial scans.
Looking at standard comparisons using averages, the scans indicated no change one week and three weeks into treatment. But, using the parametric response map approach, the researchers were able to show changes in the tumor’s blood volume and blood flow after one week that corresponded to the patient’s overall survival.
Additional authors are Thomas Chenevert, Charles Meyer, Dr. Christina Tsien, Dr. Theodore Lawrence, Dr. Daniel Hamstra, Dr. Larry Junck, Dr. Pia Sundgren, Timothy D. Johnson, David Ross and Alnawaz Rehemtulla.
— Nicole Fawcett, UMHS Public Relations
