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2013年6月7日星期五

Three-billion-year-old microfossils include plankton

"It is surprising to have large, potentially complex fossils that far back," said Christopher H. House, professor of geosciences, Penn State, and lead author.

However, the researchers not only showed that these inclusions in the rocks were biological in origin, but also that they were likely planktonic autotrophs -- free-floating, tiny ocean organisms that produce energy from their environment.

The researchers looked at marine sediment rocks from the Farrel Quartzite in Western Australia. Isotopic analysis using secondary ion mass spectrometry was carried out at UCLA. "Ken (Kenichiro Sugitani, professor, Graduate School of Environmental Studies, Nagoya University, Japan, and a co-author) discovered these unusually shaped microfossils embedded in really old rock," said House.

To determine if these inclusions were actually biological in origin, the researchers looked at 15 different samples of Farrel Quartzite and determined their stable carbon isotope ratios. The percentage of carbon 13 in the microfossils was indicative of material produced by biological processes. They found that the carbon 13 percentage in the background organic matter in the surrounding rock was different from that of the microstructures.

"When considered along with published morphological and chemical studies, these results indicate that the Farrel Quartzite microstructures are bona fide microfossils, and support the interpretation that the spindles were planktonic," the researchers report in the current issue of Geology. The morphological and chemical studies were done by Sugitani and Dorothy Oehler, who is also a co-author and research scientist, Astromaterials Research and Exploration Science Directorate, NASA -- Johnson Space Center.

The spindle-shaped microfossils are from 20 to 60 microns in length, about the size of fine sand and within the size range of today's microplankton.

Stable carbon isotope analysis can determine the biological origin of these microfossils because they used carbon dioxide to create energy and incorporated the carbon into themselves. During this process, the organisms selectively incorporate more carbon 12 than carbon 13 from the available carbon, producing a signature of biological origin.

Oehler notes that the spindles appear to be the same as those found in rocks from the Strelly Pool Formation in Western Australia and the Onverwacht Group in South Africa and Swaziland that are both 3.4 billion years old.

"The existence of these microfossils in diverse locations as far back as 3.4 billion years ago suggests that the oceans probably had life in them for a very extended period of time," said Oehler. "Moreover, this has implications beyond what we have done here, suggesting the evolution of diverse life proceeded quickly."

Also working on this project was Koichi Mimura, Graduate School of Environmental Studies, Nagoya University, Japan.

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Stars don't obliterate their planets (very often)

Now, a new study using data from NASA's Kepler Space Telescope shows that hot Jupiters, despite their close-in orbits, are not regularly consumed by their stars. Instead, the planets remain in fairly stable orbits for billions of years, until the day comes when they may ultimately get eaten.

"Eventually, all hot Jupiters get closer and closer to their stars, but in this study we are showing that this process stops before the stars get too close," said Peter Plavchan of NASA's Exoplanet Science Institute at the California Institute of Technology, Pasadena, Calif. "The planets mostly stabilize once their orbits become circular, whipping around their stars every few days."

The study, published recently in the Astrophysical Journal, is the first to demonstrate how the hot Jupiter planets halt their inward march on stars. Gravitational, or tidal, forces of a star circularize and stabilize a planet's orbit; when its orbit finally become circular, the migration ceases.

"When only a few hot Jupiters were known, several models could explain the observations," said Jack Lissauer, a Kepler scientist at NASA's Ames Research Center, Moffet Field, Calif., not affiliated with the study. "But finding trends in populations of these planets shows that tides, in combination with gravitational forces by often unseen planetary and stellar companions, can bring these giant planets close to their host stars."

Hot Jupiters are giant balls of gas that resemble Jupiter in mass and composition. They don't begin life under the glare of a sun, but form in the chilly outer reaches, as Jupiter did in our solar system. Ultimately, the hot Jupiter planets head in toward their stars, a relatively rare process still poorly understood.

The new study answers questions about the end of the hot Jupiters' travels, revealing what put the brakes on their migration. Previously, there were a handful of theories explaining how this might occur. One theory proposed that the star's magnetic field prevented the planets from going any farther. When a star is young, a planet-forming disk of material surrounds it. The material falls into the star -- a process astronomers call accretion -- but when it hits the magnetic bubble around it, called the magnetosphere, the material travels up and around the bubble, landing on the star from the top and bottom. This bubble could be halting migrating planets, so the theory went.

Another theory held that the planets stopped marching forward when they hit the end of the dusty portion of the planet-forming disk.

"This theory basically said that the dust road a planet travels on ends before the planet falls all the way into the star," said co-author Chris Bilinski of the University of Arizona, Tucson. "A gap forms between the star and the inner edge of its dusty disk where the planets are thought to stop their migration."

And yet a third theory, the one the researchers found to be correct, proposed that a migrating planet stops once the star's tidal forces have completed their job of circularizing its orbit.

To test these and other scenarios, the scientists looked at 126 confirmed planets and more than 2,300 candidates. The majority of the candidates and some of the known planets were identified via NASA's Kepler mission. Kepler has found planets of all sizes and types, including rocky ones that orbit where temperatures are warm enough for liquid water.

The scientists looked at how the planets' distance from their stars varied depending on the mass of the star. It turns out that the various theories explaining what stops migrating planets differ in their predictions of how the mass of a star affects the orbit of the planet. The "tidal forces" theory predicted that the hot Jupiters of more massive stars would orbit farther out, on average.

The survey results matched the "tidal forces" theory and even showed more of a correlation between massive stars and farther-out orbits than predicted.

This may be the end of the road for the mystery of what halts migrating planets, but the journey itself still poses many questions. As gas giants voyage inward, it is thought that they sometimes kick smaller, rocky planets out of the way, and with them any chance of life evolving. Lucky for us, our Jupiter did not voyage toward the sun, and our Earth was left in peace. More studies like this one will help explain these and other secrets of planetary migration.

The technical paper is online at http://iopscience.iop.org/0004-637X/769/2/86/ .

NASA Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development. Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with JPL at the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters in Washington.

NASA's Exoplanet Science Institute at Caltech manages time allocation on the Keck telescope for NASA. JPL manages NASA's Exoplanet Exploration program office. Caltech manages JPL for NASA.

More information about the Kepler mission is at http://www.nasa.gov/kepler .

More information about exoplanets and NASA's planet-finding program is at http://planetquest.jpl.nasa.gov .

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'Dust trap' around young star solves long-standing planet formation mystery

June 6, 2013 — Astronomers using the new Atacama Large Millimeter/submillimeter Array (ALMA) have imaged a region around a young star where dust particles can grow by clumping together. This is the first time that such a dust trap has been clearly observed and modelled. It solves a long-standing mystery about how dust particles in discs grow to larger sizes so that they can eventually form comets, planets and other rocky bodies. The results are published in the journal Science on 7 June 2013.

Astronomers now know that planets around other stars are plentiful. But they do not fully understand how they form and there are many aspects of the formation of comets, planets and other rocky bodies that remain a mystery. However, new observations exploiting the power of ALMA are now answering one of the biggest questions: how do tiny grains of dust in the disc around a young star grow bigger and bigger -- to eventually become rubble, and even boulders well beyond a metre in size?

Computer models suggest that dust grains grow when they collide and stick together. However, when these bigger grains collide again at high speed they are often smashed to pieces and sent back to square one. Even when this does not happen, the models show that the larger grains would quickly move inwards because of friction between the dust and gas and fall onto their parent star, leaving no chance that they could grow even further.

Somehow the dust needs a safe haven where the particles can continue growing until they are big enough to survive on their own [1]. Such "dust traps" have been proposed, but there was no observational proof of their existence up to now.

Nienke van der Marel, a PhD student at Leiden Observatory in the Netherlands, and lead author of the article, was using ALMA along with her co-workers, to study the disc in a system called Oph-IRS 48 [2]. They found that the star was circled by a ring of gas with a central hole that was probably created by an unseen planet or companion star. Earlier observations using ESO's Very Large Telescope had already shown that the small dust particles also formed a similar ring structure. But the new ALMA view of where the larger millimetre-sized dust particles were found was very different!

"At first the shape of the dust in the image came as a complete surprise to us," says van der Marel. "Instead of the ring we had expected to see, we found a very clear cashew-nut shape! We had to convince ourselves that this feature was real, but the strong signal and sharpness of the ALMA observations left no doubt about the structure. Then we realised what we had found."

What had been discovered was a region where bigger dust grains were trapped and could grow much larger by colliding and sticking together. This was a dust trap -- just what the theorists were looking for.

As van der Marel explains: "It's likely that we are looking at a kind of comet factory as the conditions are right for the particles to grow from millimetre to comet size. The dust is not likely to form full-sized planets at this distance from the star. But in the near future ALMA will be able to observe dust traps closer to their parent stars, where the same mechanisms are at work. Such dust traps really would be the cradles for new-born planets."

The dust trap forms as bigger dust particles move in the direction of regions of higher pressure. Computer modelling has shown that such a high pressure region can originate from the motions of the gas at the edge of a gas hole -- just like the one found in this disc.

"The combination of modelling work and high quality observations of ALMA makes this a unique project," says Cornelis Dullemond from the Institute for Theoretical Astrophysics in Heidelberg, Germany, who is an expert on dust evolution and disc modelling, and a member of the team. "Around the time that these observations were obtained, we were working on models predicting exactly these kinds of structures: a very lucky coincidence."

The observations were made while the ALMA array was still being constructed. They made use of the ALMA Band 9 receivers [3] -- European-made devices that allow ALMA to create its so far sharpest images.

"These observations show that ALMA is capable of delivering transformational science, even with less than half of the full array in use," says Ewine van Dishoeck of the Leiden Observatory, who has been a major contributor to the ALMA project for more than 20 years. "The incredible jump in both sensitivity and image sharpness in Band 9 gives us the opportunity to study basic aspects of planet formation in ways that were simply not possible before."

Notes:

[1] The cause of the dust trap, in this case a vortex in the disc's gas', has typical life spans of hundreds of thousand of years. Even when the dust trap ceases to work, the dust accumulated in the trap would take millions of years to disperse providing ample time for the dust grains to grow larger.

[2] The name is a combination of the constellation name of the star-forming region where the system is found and the type of source, so Oph stands for the constellation of Ophiuchus (The Serpent Bearer), and the IRS stands for infrared source. The distance from Earth to Oph-IRS 48 is about 400 light-years.

[3] ALMA can observe in different frequency bands. Band 9, operating at wavelengths of about 0.4-0.5 millimeters, is the mode that so far provides the sharpest images.

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Scientists coax brain to regenerate cells lost in Huntington's disease in mouse model

"This study demonstrates the feasibility of a completely new concept to treat Huntington's disease, by recruiting the brain's endogenous neural stem cells to regenerate cells lost to the disease," said University of Rochester Medical Center (URMC) neurologist Steve Goldman, M.D., Ph.D., co-director of Rochester's Center for Translational Neuromedicine.

Huntington's disease is an inherited neurodegenerative disease characterized by the loss of a specific cell type called the medium spiny neuron, a cell that is critical to motor control. The disease, which affects some 30,000 people in the U.S., results in involuntary movements, problems with coordination, and, ultimately, in cognitive decline and depression. There is currently no way to slow or modify this fatal disease.

For Goldman, the idea behind his strategy to treat the disease emerged from his decades-long study of neural plasticity in canaries. Songbirds like canaries have intrigued biologists because of their ability -- unique in the animal kingdom -- to lay down new neurons in the adult brain. This process, called adult neurogenesis, was first discovered by Goldman and Fernando Nottebohm of the Rockefeller University in the early 1980s, when the two realized that when learning new songs new neurons were added to regions of the bird's brain responsible for vocal control.

"Our work with canaries essentially provided us with the information we needed to understand how to add new neurons to adult brain tissue," said Goldman. "Once we mastered how this happened in birds, we set about how to replicate the process in the adult mammalian brain."

Humans already possess the ability to create new neurons. Goldman's lab demonstrated in the 1990s that a font of neuronal precursor cells exist in the lining of the ventricles, structures found in the core of the human brain. In early development, these cells are actively producing neurons. However, shortly after birth the neural stem cells stop generating neurons and instead produce glia, a family of support cells that pervade the central nervous system. Some parts of the human brain continue to produce neurons into adulthood, the most prominent example is the hippocampus where memories are formed and stored. But in the striatum, the region of the brain that is devastated by Huntington's disease, this capability is "switched off" in adulthood.

Goldman and his team spent the past decade attempting to unravel the precise chemical signaling responsible for instructing neural stem cells when to create neurons and when to create glia cells. One of the most critical clues came directly from the earlier research with canaries. In the part of the bird's brain were new songs are acquired and neurons added, the scientists observed the regulated expression of a protein called brain derived neurotrophic factor, or BDNF. When the production of this protein is triggered, the local neural stem cells are instructed to produce neurons.

At the same time, the scientists also realized that they had to simultaneously suppress the bias of these stem cells to produce glia. They found that when BDNF was combined with another molecule called noggin -- a protein that inhibits the chemical pathway that dictates the creation of glial cells -- they could successfully switch the stem cell's molecular machinery over to the production of neurons.

The next challenge was how to deliver these two proteins -- BDNF and noggin -- precisely and in a sustained fashion to the area of the brain involved in Huntington's disease. To do so, they partnered with scientists at the University of Iowa to modify a viral gene therapeutic, called an adeno-associated virus, to deliver the necessary molecular instructions to the neural stem cells.

The virus infected the target cells in the brains of mice with Huntington's disease and triggered the sustained over-expression of both BDNF and noggin. This, in turn, activated the neighboring neural stem cells which began to produce medium spiny motor neurons. The new neurons were continuously generated and migrated to the striatum, the region of the brain impacted by Huntington's disease, where they then integrated into the existing neuronal networks.

The researchers were able to significantly extend the survival of the treated mice, in some cases doubling their life expectancy. The researchers also devised a way to tag the new neurons and observed that the cells extended fibers to distant targets within the brain and establish electrical communication.

After having established the ability to generate new replacement neurons in mouse models of Huntington's disease, the researchers also demonstrated that they could replicate this technique in the brains of normal squirrel monkeys, a step that brings the research much closer to tests in humans.

"The sustained delivery of BDNF and noggin into the adult brain was clearly associated with both increased neurogenesis and delayed disease progression," said Goldman. "We believe that our data suggest the feasibility of this process as a viable therapeutic strategy for Huntington's disease."

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Predicting the future of coral reefs in a changing world

June 6, 2013 — Rutgers scientists have described for the first time the biological process of how corals create their skeletons -- destined to become limestones -- which form massive and ecologically vital coral reefs in the world's oceans.

In a publication in Current Biology, Tali Mass and her colleagues at the Rutgers Institute of Marine and Coastal Sciences show that specific proteins produced by corals can form limestones in test tubes. These proteins, secreted by corals, precipitate carbonate that forms the corals' characteristic skeleton.

"This is a first step toward understanding how coral build their skeleton," said Mass, a post-doctoral researcher and lead author of the study. The researchers also found that the reaction occurs regardless of water acidity, which suggests that these organisms will survive in coming centuries when the world's oceans are predicted to become more acidic. That also potentially bodes well for the health of the world's coral reefs, which support ecosystems essential to marine diversity that in turn support fisheries.

"The good news is that the change in acidity will not stop the function of these proteins," said Mass. But she is quick to warn that her work shouldn't make people complacent. "Pollution and rising water temperatures also pose major threats to these essential marine organisms."

Limestone rocks are all around us and have been central human history. The Egyptians used them to build pyramids and today they are still used to build monuments. Surprisingly, all limestones are created by living organisms. The rocks are everywhere, it seems, but how they form has not been answered until now.

Scientists have long known that corals made their external skeletons from a matrix of secreted proteins, but didn't understand the mechanism. Mass and her colleagues in Paul Falkowski's laboratory began by asking which proteins might be responsible for the process. They identified over 30 proteins from coral skeleton that could be involved. They described that work earlier this year in the journal, Proceedings of the National Academy of Sciences.

At the same time they searched for genes in the coral genome for proteins that could potentially assist with production of the skeletal mineral calcium carbonate. For this, the scientists went to Debashish Bhattacharya, professor of ecology, evolution and natural resources, director of the Rutgers Genome Cooperative, and a co-author of the paper. A genome is the entirety of an organism's genetic information (DNA) -- in this case, of the particular coral that the researchers were studying.

"We produced a 'draft' genome," Bhattacharya said. "Basically, that's a genome that is not yet fully assembled into chromosomes. So, you don't have the DNA puzzle completely put together, but you have all of the pieces of that puzzle and can figure out what the many pieces -- for example, the genes -- do in the coral."

The genome analysis, done by Ehud Zelzion, bioinformaticist at the Genome Cooperative, led the researchers to four particular proteins. The genes encoding these proteins were cloned and expressed in bacteria, then isolated and placed in solutions representing the current acidity of seawater and the more acidic levels scientists predict for the end of the century.

On the commonly used pH scale, where lower numbers are more acidic, today's seas are a moderately alkaline 8.2. But they are expected to creep toward 7.6 as carbon dioxide concentration increases in the air. Using a scanning electron microscope and other measurement devices, the scientists examined the proteins and found that all had begun to precipitate calcium carbonate crystals in the test tube at both pH levels.

"This work goes a long way toward explaining how corals precipitate calcium carbonate skeletons and clearly shows that the reaction can work at more acidic pH levels," said Falkowski, also a co-author of the study and Board of Governors Professor of geological and marine sciences. "It doesn't mean that ocean acidification is not a concern, but it does suggest that corals will still be able to form skeletons, and coral reefs will continue to exist."

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MRI study: Breastfeeding boosts babies' brain growth

June 6, 2013 — A study using brain images from "quiet" MRI machines adds to the growing body of evidence that breastfeeding improves brain development in infants. Breastfeeding alone produced better brain development than a combination of breastfeeding and formula, which produced better development than formula alone.

A new study by researchers from Brown University finds more evidence that breastfeeding is good for babies' brains.

The study made use of specialized, baby-friendly magnetic resonance imaging (MRI) to look at the brain growth in a sample of children under the age of 4. The research found that by age 2, babies who had been breastfed exclusively for at least three months had enhanced development in key parts of the brain compared to children who were fed formula exclusively or who were fed a combination of formula and breastmilk. The extra growth was most pronounced in parts of the brain associated with language, emotional function, and cognition, the research showed.

This isn't the first study to suggest that breastfeeding aids babies' brain development. Behavioral studies have previously associated breastfeeding with better cognitive outcomes in older adolescents and adults. But this is the first imaging study that looked for differences associated with breastfeeding in the brains of very young and healthy children, said Sean Deoni, assistant professor of engineering at Brown and the study's lead author.

"We wanted to see how early these changes in brain development actually occur," Deoni said. "We show that they're there almost right off the bat."

The findings are in press in the journal NeuroImage and available now online.

Deoni leads Brown's Advanced Baby Imaging Lab. He and his colleagues use quiet MRI machines that image babies' brains as they sleep. The MRI technique Deoni has developed looks at the microstructure of the brain's white matter, the tissue that contains long nerve fibers and helps different parts of the brain communicate with each other. Specifically, the technique looks for amounts of myelin, the fatty material that insulates nerve fibers and speeds electrical signals as they zip around the brain.

Deoni and his team looked at 133 babies ranging in ages from 10 months to four years. All of the babies had normal gestation times, and all came from families with similar socioeconomic statuses. The researchers split the babies into three groups: those whose mothers reported they exclusively breastfed for at least three months, those fed a combination of breastmilk and formula, and those fed formula alone. The researchers compared the older kids to the younger kids to establish growth trajectories in white matter for each group.

The study showed that the exclusively breastfed group had the fastest growth in myelinated white matter of the three groups, with the increase in white matter volume becoming substantial by age 2. The group fed both breastmilk and formula had more growth than the exclusively formula-fed group, but less than the breastmilk-only group.

"We're finding the difference [in white matter growth] is on the order of 20 to 30 percent, comparing the breastfed and the non-breastfed kids," said Deoni. "I think it's astounding that you could have that much difference so early."

Deoni and his team then backed up their imaging data with a set of basic cognitive tests on the older children. Those tests found increased language performance, visual reception, and motor control performance in the breastfed group.

The study also looked at the effects of the duration of breastfeeding. The researchers compared babies who were breastfed for more than a year with those breastfed less than a year, and found significantly enhanced brain growth in the babies who were breastfed longer -- especially in areas of the brain dealing with motor function.

Deoni says the findings add to a substantial body of research that finds positive associations between breastfeeding and children's brain health.

"I think I would argue that combined with all the other evidence, it seems like breastfeeding is absolutely beneficial," he said.

Other authors on the study were Douglas Dean, Irene Piryatinsky, Jonathan O'Muircheartaigh, Lindsay Walker, Nicole Waskiewicz, Katie Lehman, Michelle Han and Holly Dirks, who all work with Deoni in the Baby Imaging Lab. The work was funded by the National Institutes of Mental Health.

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Kickstarter startup kicked upstairs to Logitech

PARIS – The news about Logitech’s acquisition of TT Design Labs, a two-member startup that originated on the crowd -funding Kickstarter program, is generating feel-good vibes in the design and engineering community today.

TT Design Labs was founded by Zahra Tashakorinia and Derek Tarnow, two designers who developed TidyTilt -- a little magnetic device which serves as an iPhone stand, mount and earbud-cord organizer.

While Logitech, a Switzerland-based manufacturer of traditional computer accessories such as mice and keyboards, isn’t disclosing the financial terms of the deal, the company is re-launching TT Design Labs’ TidyTilt, TidyTilt+ and Just Mount in Logitech-branded versions. It has hired the two entrepreneurs to design future Logitech products. Tarnow joins Logitech as a product designer with Tashakorinia as a consultant.

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2013年6月6日星期四

Scientists unexpectedly discover stress-resistant stem cells in fat tissue removed during liposuction

The cells, called Multi-lineage Stress-Enduring (Muse-AT) stem cells from fat, or adipose, tissue, were discovered by "scientific accident" when a piece of equipment failed in the lab, killing all the stem cells in the experiment except for the Muse-AT cells. The research team further discovered that not only are Muse-AT cells able to survive severe stress, they may even be activated by it, said study senior author Gregorio Chazenbalk, an associate researcher with UCLA Obstetrics and Gynecology.

These pluripotent cells, isolated from fat tissue removed during liposuction, expressed many embryonic stem cell markers and were able to differentiate into muscle, bone, fat, cardiac, neuronal and liver cells. An examination of their genetic characteristics confirmed their specialized functions, as well as their capacity to regenerate tissue when transplanted back into the body following their "awakening."

"This population of cells lies dormant in the fat tissue until it is subjected to very harsh conditions. These cells can survive in conditions in which usually only cancer cells can live," Chazenbalk said. "Upon further investigation and clinical trials, these cells could prove a revolutionary treatment option for numerous diseases, including heart disease, stroke and for tissue damage and neural regeneration."

The results of the two-year study are published June 5, 2013 in the peer-reviewed journal PLOS ONE.

Purifying and isolating Muse-AT cells does not require the use of a cell sorter or other specialized, high-tech devices. They are able to grow either in suspension, forming cell spheres, or as adherent cells, forming cell aggregates very similar to human embryonic stem cell-derived embryoid bodies.

"We have been able to isolate these cells using a simple and efficient method that takes about six hours from the time the fat tissue is harvested," said Chazenbalk,a scientist with the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research. "This research offers a new and exciting source of fat stem cells with pluripotent characteristics, as well as a new method for quickly isolating them. These cells also appear to be more primitive than the average fat stem cells, making them potentially superior sources for regenerative medicine."

Currently, embryonic stem cells and induced pluripotent stem cells -- skin cells turned into embryonic-like cells -- are the two main sources of pluripotent cells. However, both types can exhibit an uncontrolled capacity for differentiation and proliferation, leading to the formation of unwanted teratoma, or tumors. Little progress has been made in resolving that defect, Chazenbalk said.

Muse cells originally were discovered by a research group at Tokohu University in Japan and were derived from bone marrow and skin, rather than fat. That research group showed that Muse cells did not produce teratomas in animal models. Further research on the Muse-AT cells isolated at UCLA will need to be done to determine whether that cell population avoids production of teratomas.

In addition to providing a potential source of cells for regenerative medicine, Chazenbalk said the Muse-AT cells may provide a better understanding of cancer cells, the only other cells known to display such stress resistance.

Going forward, Chazenbalk and his team will use Muse-AT cells in animal models to regenerate damaged or dysfunctional tissue to determine how efficiently they grow and perform in the body and to gauge their potential for future clinical use.

"Because lipoaspiration is a safe and non-invasive procedure and Muse-AT cell isolation requires a simple yet highly efficient purification technique, Muse-AT cells could provide an ideal source of pluripotent-like stem cells," the study states. "Muse-AT cells have the potential to make a critical impact on the field of regenerative medicine."

The study was funded by the UCLA Department of Obstetrics and Gynecology, the Eunice Kennedy Shriver National Institute of Child Health & Human Development , the National Institutes of Health through the cooperative agreement U54 HD071836 and by the Department of Stem Cell Biology at Tohoku University in Japan.

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A 20-minute bout of yoga stimulates brain function immediately after

June 5, 2013 — Researchers report that a single, 20-minute session of Hatha yoga significantly improved participants' speed and accuracy on tests of working memory and inhibitory control, two measures of brain function associated with the ability to maintain focus and take in, retain and use new information. Participants performed significantly better immediately after the yoga practice than after moderate to vigorous aerobic exercise for the same amount of time.

The 30 study subjects were young, female, undergraduate students. The new findings appear in the Journal of Physical Activity and Health.

"Yoga is an ancient Indian science and way of life that includes not only physical movements and postures but also regulated breathing and meditation," said Neha Gothe, who led the study while a graduate student at the University of Illinois at Urbana-Champaign. Gothe now is a professor of kinesiology, health and sport studies at Wayne State University in Detroit. "The practice involves an active attentional or mindfulness component but its potential benefits have not been thoroughly explored."

"Yoga is becoming an increasingly popular form of exercise in the U.S. and it is imperative to systematically examine its health benefits, especially the mental health benefits that this unique mind-body form of activity may offer," said Illinois kinesiology and community health professor Edward McAuley, who directs the Exercise Psychology Laboratory where the study was conducted.

The yoga intervention involved a 20-minute progression of seated, standing and supine yoga postures that included isometric contraction and relaxation of different muscle groups and regulated breathing. The session concluded with a meditative posture and deep breathing.

Participants also completed an aerobic exercise session where they walked or jogged on a treadmill for 20 minutes. Each subject worked out at a suitable speed and incline of the treadmill, with the goal of maintaining 60 to 70 percent of her maximum heart rate throughout the exercise session.

"This range was chosen to replicate previous findings that have shown improved cognitive performance in response to this intensity," the researchers reported.

Gothe and her colleagues were surprised to see that participants showed more improvement in their reaction times and accuracy on cognitive tasks after yoga practice than after the aerobic exercise session, which showed no significant improvements on the working memory and inhibitory control scores.

"It appears that following yoga practice, the participants were better able to focus their mental resources, process information quickly, more accurately and also learn, hold and update pieces of information more effectively than after performing an aerobic exercise bout," Gothe said. "The breathing and meditative exercises aim at calming the mind and body and keeping distracting thoughts away while you focus on your body, posture or breath. Maybe these processes translate beyond yoga practice when you try to perform mental tasks or day-to-day activities."

Many factors could explain the results, Gothe said. "Enhanced self-awareness that comes with meditational exercises is just one of the possible mechanisms. Besides, meditation and breathing exercises are known to reduce anxiety and stress, which in turn can improve scores on some cognitive tests," she said.

"We only examined the effects of a 20-minute bout of yoga and aerobic exercise in this study among female undergraduates," McAuley said. "However, this study is extremely timely and the results will enable yoga researchers to power and design their interventions in the future. We see similar promising findings among older adults as well. Yoga research is in its nascent stages and with its increasing popularity across the globe, researchers need to adopt rigorous systematic approaches to examine not only its cognitive but also physical health benefits across the lifespan."

The research team included U. of I. kinesiology and community health professor Charles Hillman and Michigan State University kinesiology professor Matthew Pontifex (a U. of I. alumnus).

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Researchers announce discovery of oldest-known fossil primate skeleton

The scientific paper describing the discovery appears today in the journal Nature.

The international team of scientists who studied the skeleton of Archicebus was led by Dr. Xijun Ni of the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) at the Chinese Academy of Sciences in Beijing. Ni's collaborators include Dr. Christopher Beard of the Carnegie Museum of Natural History in Pittsburgh; Dr. Daniel Gebo of Northern Illinois University; Dr. Marian Dagosto of Northwestern University in Chicago; Dr. Jin Meng and Dr. John Flynn of the American Museum of Natural History in New York; and Dr. Paul Tafforeau of the European Synchrotron Radiation Facility in Grenoble, France. According to Dr. Ni, "Archicebus marks the first time that we have a reasonably complete picture of a primate close to the divergence between tarsiers and anthropoids. It represents a big step forward in our efforts to chart the course of the earliest phases of primate and human evolution."

Archicebus achilles

The skeleton of Archicebus is about 7 million years older than the oldest fossil primate skeletons known previously, which include Darwinius from Messel in Germany and Notharctus from the Bridger Basin in Wyoming. Furthermore, Archicebus belongs to an entirely separate branch of the primate evolutionary tree that lies much closer to the lineage leading to modern monkeys, apes and humans. Darwinius and Notharctus, on the other hand, are adapiform primates that are early relatives of living lemurs, the most distant branch of the primate family tree with respect to humans and other anthropoids.

Dr. Christopher Beard, whose earlier work on Eosimias and other fossil primates from China and Myanmar has placed Asia at the center of early primate evolution, said that, "Archicebus differs radically from any other primate, living or fossil, known to science. It looks like an odd hybrid with the feet of a small monkey, the arms, legs and teeth of a very primitive primate, and a primitive skull bearing surprisingly small eyes. It will force us to rewrite how the anthropoid lineage evolved."

Statistical analyses aimed at reconstructing how much an adult Archicebus would have weighed in life show that it was slightly smaller than the smallest living primates, which are pygmy mouse lemurs from Madagascar. Archicebus would have weighed about 20-30 grams (~ 1 ounce). Dr. Daniel Gebo, an expert on the evolution of body anatomy in primates, said that, "The tiny size and very basal evolutionary position of Archicebus support the idea that the earliest primates, as well as the common ancestor of tarsiers and anthropoids, were miniscule. This overturns earlier ideas suggesting that the earliest members of the anthropoid lineage were quite large, the size of modern monkeys."

Dr. Marian Dagosto notes that, "Even though Archicebus appears to be a very basal member of the tarsier lineage, it resembles early anthropoids in several features, including its small eyes and monkey-like feet. It suggests that the common ancestor of tarsiers and anthropoids was in some ways more similar than most scientists have thought."

The evolutionary relationships among primates and their potential relatives, and among the major lineages within the Primate order have been debated intensively for many years. "To test these different hypotheses and determine the phylogenetic position of the new primate, we developed a massive data matrix including more than 1000 anatomical characters and scored for 157 mammals," said Dr. Jin Meng.

The new fossil takes its name from the Greek arche (meaning beginning or first; the same root as archaeology) and the Greek kebos (meaning long-tailed monkey). The species name achilles (derived from the mythological Greek warrior achilles) highlights the new fossil's unusual ankle anatomy.

Archicebus: exhumed and digitally resurrected

The fossil was recovered from sedimentary rock strata that were deposited in an ancient lake roughly 55 million years ago, during the early part of the Eocene epoch. This was an interval of global "greenhouse" conditions, when much of the world was shrouded in tropical rainforests and palm trees grew as far north as Alaska. Like most other fossils recovered from ancient lake strata, the skeleton of Archicebus was found by splitting apart the thin layers of rock containing the fossil. As a result, the skeleton of Archicebus is now preserved in two complementary pieces called a "part" and a "counterpart," each of which contain elements of the actual skeleton as well as impressions of bones from the other side.

In order to study the entire fossil, the scientific team first had to scan the specimen at ultra high resolution using the state-of-the-art facilities of the European Synchrotron Radiation Facility in Grenoble, France. Three-dimensional digital reconstruction of the fossil using the synchrotron scans allowed the team of scientists to study the tiny, fragile skeleton of Archicebus in intricate detail. "During the past few years, we at the ESRF have developed the technology to look at those parts of the fossil that are still buried in the rock at a level of detail that is unique in the world. Speaking virtually, we made the skeleton stand up," said Dr. Paul Tafforeau, a leading expert in developing paleontological applications of highly sophisticated Synchrotron CT scanning.

"People may see this simply as another discovery of a well preserved fossil, but to reveal the remarkable secrets that have been hidden in the rock for millions of years, we undertook extensive work, applied state-of-the-art technology, and intensive international cooperation took place behind the scenes at several museums. It took us ten years," added Dr. John Flynn, dean of the Richard Gilder Graduate School and curator of the American Museum of Natural History.

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