Heart health tip for older adults in 2023: Step it up a bit

The evidence-based health benefits of walking continue to accumulate, according to ongoing research by a University of Massachusetts Amherst physical activity epidemiologist, who leads an international consortium known as the Steps for Health Collaborative.

Findings from the latest study led by Amanda Paluch, assistant professor of kinesiology in the School of Public Health and Health Sciences, show that older adults who walked between 6,000 and 9,000 steps per day had a 40-50% reduced risk of a cardiovascular event, such as a heart attack or stroke, compared to those who walked 2,000 steps per day.

"We found for adults over 60, there was a strikingly lower risk of a cardiovascular event or disease over an average follow-up of six years," says Paluch, whose team's research was published this week in the journal Circulation. "When accumulating more steps per day, there was a progressively lower risk."

Earlier this year, research by Paluch and the Steps for Health Collaborative showed that more movement, even below the highly touted but unscientific "10,000 steps per day," was associated with longevity benefits. The meta-analysis of 15 studies involving nearly 50,000 people from four continents found that walking between 6,000 and 8,000 steps per day was linked with a lower risk of death from all causes among older adults.

Following those findings, Paluch and team wanted to tackle the less-charted territory of steps per day and cardiovascular disease. The results were similar, in terms of the most beneficial range of steps.

While there appears to be a continual additional benefit for those who walk more than 6,000 steps, Paluch says, encouraging the least-active older adults to take more steps is perhaps the most important public health message.

"The people who are the least active have the most to gain," she says. "For those who are at 2,000 or 3,000 steps a day, doing a little bit more can mean a lot for their heart health. If you're at 6,000 steps, getting to 7,000 and then to 8,000 also is beneficial, it's just a smaller, incremental improvement."

The meta-analysis of eight studies involved more than 20,000 people from the U.S. and 42 other countries. For younger adults, no link between steps per day and cardiovascular risk was detected.

"This is because cardiovascular disease is a disease of aging and often doesn't come to fruition until we're at older ages," says Paluch, whose project was supported by the Centers for Disease Control and Prevention (CDC). "You're not going to see many people develop cardiovascular disease after six years of follow-up in young to middle adulthood."

Future research involving younger adults and steps per day would focus on the precursors of cardiovascular disease, including high blood pressure, obesity and type 2 diabetes. "Those conditions develop in younger adults and are important for early prevention," Paluch says.

Four of the eight studies the researchers analyzed included data about walking intensity, or how fast the steps were taken. "We're interpreting these results with caution, but we did not find any striking association with walking intensity," she says. "There was no additional benefit with how fast you're walking, beyond the total number of steps that you accumulated."

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Common food dye can trigger inflammatory bowel diseases, animal study suggests

Long-term consumption of Allura Red food dye can be a potential trigger of inflammatory bowel diseases (IBDs), Crohn's disease and ulcerative colitis, says McMaster University's Waliul Khan. Researchers using experimental animal models of IBD found that continual exposure to Allura Red AC harms gut health and promotes inflammation.

The dye directly disrupts gut barrier function and increases the production of serotonin, a hormone/neurotransmitter found in the gut, which subsequently alters gut microbiota composition leading to increased susceptibility to colitis.

Khan said Allura Red (also called FD&C Red 40 and Food Red 17), is a common ingredient in candies, soft drinks, dairy products and some cereals. The dye is used to add colour and texture to foodstuffs, often to attract children.

The use of synthetic food dyes such as Allura Red has increased significantly over the last several decades, but there has been little earlier study of these dyes' effects on gut health. Khan and his team published their findings in Nature Communications. Yun Han (Eric) Kwon, who recently completed PhD in Khan's laboratory, is first author.

"This study demonstrates significant harmful effects of Allura Red on gut health and identifies gut serotonin as a critical factor mediating these effects. These findings have important implication in the prevention and management of gut inflammation," said Khan, the study's senior author, a professor of the Department of Pathology and Molecular Medicine and a principal investigator of Farncombe Family Digestive Health Research Institute.

"What we have found is striking and alarming, as this common synthetic food dye is a possible dietary trigger for IBDs. This research is a significant advance in alerting the public on the potential harms of food dyes that we consume daily," he said.

"The literature suggests that the consumption of Allura Red also affects certain allergies, immune disorders and behavioural problems in children, such as attention deficit hyperactivity disorder."

Khan said that IBDs are serious chronic inflammatory conditions of the human bowel that affect millions of people worldwide. While their exact causes are still not fully understood, studies have shown that dysregulated immune responses, genetic factors, gut microbiota imbalances, and environmental factors can trigger these conditions.

In recent years there has been significant progress in identifying susceptibility genes and understanding the role of the immune system and host microbiota in the pathogenesis of IBDs. However, similar advances in defining environmental risk factors have lagged, he said.

Khan said that environmental triggers for IBDs include the typical Western diet, which includes processed fats, red and processed meats, sugar and a lack of fibre. He added that the Western diet and processed food also includes large amounts of various additives and dyes.

He added that the study suggests a link between a commonly used food dye and IBDs and warrants further exploration between food dyes and IBDs at experimental, epidemiological and clinical levels.

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Early forests did not significantly change the atmospheric CO2

Scientists have discovered that the atmosphere contained far less CO2 than previously thought when forests emerged on our planet, the new study has important implications for understanding how land plants affect the climate.

The research has been led by the University of Copenhagen in collaboration with the University of Nottingham and alters 30 years of previous understanding. The study is published in Nature Communications.

Earth's continents were colonized by tall trees and forests about 385 million years ago. Before then, shallow shrub-like plants with vascular tissue, stems, shallow roots, and no flowers had invaded the land. Textbooks tell us that the atmosphere at that time had far higher CO2 levels than today and that an intense greenhouse effect led to a much warmer climate. The emergence of forests was previously thought to promote CO2 removal from the atmosphere, driving the Earth into a long cool period with ice cover at the poles.

Reconstructing atmospheric CO2 levels in the geological past is difficult and has previously relied on proxies that also depend on parameters that had to be assumed. Climate scientists agree that CO2 plays a crucial role in shaping Earth's climate both today and in the past. Therefore, a grand challenge for Earth scientist is to understand what has controlled the abundance CO2 in the atmosphere.

"We calibrated a mechanistic model for the gas-exchange between plant leaves and the ambient air to the oldest lineage of vascular land plants, namely clubmosses. With this approach, we could calculate the CO2 level in the air solely from observations made on the plant material," tells associate professor Tais W. Dahl from the Globe institute at University of Copenhagen, who led the study in collaboration with an international team of researchers from Germany, Saudi Arabia, UK, and USA.

The new method builds on three observations that can be made both in living plants and fossil plant tissue, including the ratio of two stable carbon isotopes and the size and density of stomata (pore openings) through which CO2 is taken up by the plant. The researchers calibrated the method in living clubmosses and found that this approach can accurately reproduce ambient CO2 levels in the greenhouse.

"The newly calibrated method to study CO2 levels from the geological record is superior to previous approaches that produce estimates with unbound error bars simply because they depend on parameters that cannot be independently constrained in the geological record," says Barry Lomax Professor at University of Nottingham and a co-author on the study.

The research team applied the method to some of the oldest vascular plant fossils that lived before and after trees evolved on our planet and discovered that the ratio of the two stable carbon isotopes, carbon-13 and carbon-12, is very similar to that of modern plants. Further, the stomata density and size were also very similar to that observed in their living descendants. These observations kickstarted a more thorough investigation of the early CO2 record.

Dahl and colleagues collected data from 66 fossils of three distinct species of club mosses found in 9 different localities worldwide 410 to 380 million years in age. In all cases, the atmospheric CO2 levels were only 30-70% higher (~525 -- 715 ppm) than today (~415 ppm). This is far lower than previously thought (2000-8000 ppm). Ppm stands for parts-per-million and is the unit used to measure carbon dioxide concentrations in air.

The team utilized a paleoclimate model to show that Earth was a temperate planet with mean tropical surface air temperatures of 24.1-24.6°C.

"We used a fully coupled atmosphere-ocean model to find that Earth had ice-covered poles when forests emerged. Yet, land plants could thrive in the tropical, subtropical and temperate zones," explains Georg Feulner from the Potsdam Institute for Climate in Germany, who co-authored the study.

The new study suggest that trees actually play an insignificant role on atmospheric CO2 levels over longer time scales because early trees had deeper root systems and produced more developed soils that are associated with lower nutrient loss. With more efficient nutrient recycling in soils, trees actually have a smaller weathering demand than the shallow shrub-like vegetation that came before them. This idea goes against previous thinking that trees with deeper root system promoted CO2 removal through enhanced chemical weathering and dissolution of silicate rocks.

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Cracking the mystery behind a deadly brain cancer

The brain cancer, glioblastoma, is a fierce and formidable opponent. Its millions of victims include Senator John McCain, President Biden's son, Beau, and famed film critic Gene Siskel, to name just a few. Most patients succumb within two years and few make it past five, a statistic that hasn't improved in decades due to lack of effective treatment options.

"The aggressiveness of glioblastoma is notorious," says Cold Spring Harbor Laboratory (CSHL) Professor Alea Mills. "The norm is to do surgery, treat with harsh drugs, and just hope for the best." But now, Mills and her colleagues have discovered in this deadly cancer a vulnerability, known as BRD8, that may finally lead to new treatment options and better patient outcomes.

The CSHL team recently solved a decades-old mystery surrounding glioblastoma's aggressiveness by linking the BRD8 protein to another protein, named P53. A staple in the body's natural cancer defenses, P53 prevents cells from overgrowing and turning into tumors. Almost all cancers depend on P53 becoming mutated and thus disabled. But weirdly, in the majority of glioblastoma cases, P53 is unscathed. "So why does this cancer act like P53 is broken?" asked CSHL postdoctoral fellow Xueqin Sun. This critical question led Mills' team to discover that BRD8 had gone rogue in glioblastoma, crippling P53 in a completely new way.

BRD8 shuts down access to genes in chromosomes. If a gene is wound up tightly, it cannot be used -- it's as if it were "asleep." Mills and her team revealed that BRD8 was inappropriately active in glioblastoma, keeping many of P53's critical anticancer defenses at rest. When the researchers inactivated BRD8 via genome editing, P53's "arsenal" suddenly woke up and began blocking tumor growth.

"It's like BRD8 is saying 'NO ENTRY' to P53's tumor-preventing power, but when we hit BRD8 in the right way -- go in there almost like a scalpel, but molecularly -- the tumor is annihilated," Mills explains. She and her team implanted tumor cells from glioblastoma patients into mice and watched the tumors grow in the brain. When BRD8 was inactivated, P53 was unlocked -- the tumors stopped growing and the mice lived longer.

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The other paleo diet: Rare discovery of dinosaur remains preserved with its last meal

Microraptor was an opportunistic predator, feeding on fish, birds, lizards -- and now small mammals. The discovery of a rare fossil reveals the creature was a generalist carnivore in the ancient ecosystem of dinosaurs.

Finding the last meal of any fossil animal is rare. When McGill University Professor Hans Larsson saw a complete mammal foot inside the rib cage of the small, feathered dinosaur, his jaw dropped. Of the many hundreds of carnivorous dinosaur skeletons, only 20 cases preserve their last meals. This new find makes 21.

"At first, I couldn't believe it. There was a tiny rodent-like mammal foot about a centimeter long perfectly preserved inside a Microraptor skeleton. These finds are the only solid evidence we have about the food consumption of these long extinct animals -- and they are exceptionally rare," says Larsson, who came across the fossil while visiting museum collections in China.

Microraptor was not a picky eater

Fully feathered with wings on both its arms and legs, this dinosaur is closely linked to the origin of birds. Microraptor was about the size of a crow and one of the smallest dinosaurs. The first specimen was discovered in deposits in Liaoning, China, in the early 2000s.

"We already know of Microraptor specimens preserved with parts of fish, a bird, and a lizard in their bellies. This new find adds a small mammal to their diet, suggesting these dinosaurs were opportunistic and not picky eaters," says Larsson who is a Professor of Biology at the Redpath Museum of McGill University.

"Knowing they were not specialized to any particular food is a big deal," he adds. According to the team of researchers, this could be the first evidence of a generalist carnivore in dinosaur ecosystems. Generalist predators are important stabilizers in today's ecosystems, like foxes and crows, because they can feed among several species that may have differing population abundances.

"Knowing that Microraptor was a generalist carnivore puts a new perspective on how ancient ecosystems may have worked and a possible insight into the success of these small, feathered dinosaurs," says Larsson.

From Science Daily

Exquisite views of distant galaxies

For decades, the Hubble Space Telescope and ground-based telescopes have provided us with spectacular images of galaxies. This all changed when the James Webb Space Telescope (JWST) launched in December 2021 and successfully completed commissioning during the first half of 2022. For astronomers, the universe, as we had seen it, is now revealed in a new way never imagined by the telescope's Near-Infrared Camera(NIRCam) instrument.

The NIRCam is Webb's primary imager that covers the infrared wavelength range from 0.6 to 5 microns. NIRCam detects light from the earliest stars and galaxies in the process of formation, the population of stars in nearby galaxies, as well as young stars in the Milky Way and Kuiper Belt objects.

The Prime Extragalactic Areas for Reionization and Lensing Science, or PEARLS, project is the subject of a recent study published in Astronomical Journal by a team of researchers, including Arizona State University School of Earth and Space Exploration Regents Professor Rogier Windhorst, Research Scientist Rolf Jansen, Associate Research Scientist Seth Cohen, Research Assistant Jake Summers and Graduate Associate Rosalia O'Brien, along with the contribution of many other researchers.

For researchers, the PEARLS program's images of the earliest galaxies show the amount of gravitational lensing of objects in the background of massive clusters of galaxies, allowing the team to see some of these very distant objects. In one of these relatively deep fields, the team has worked with stunning multicolor images to identify interacting galaxies with active nuclei.

Windhorst and his team's data show evidence for giant black holes in their center where you can see the accretion disc -- the stuff falling into the black hole, shining very brightly in the galaxy center. Plus, lots of galactic stars show up like drops on your car's windshields -- like you're driving through intergalactic space. This colorful field is straight up from the ecliptic plane, the plane in which the Earth and the moon, and all the other planets, orbit around the sun.

"For over two decades, I've worked with a large international team of scientists to prepare our Webb science program," Windhorst said. "Webb's images are truly phenomenal, really beyond my wildest dreams. They allow us to measure the number density of galaxies shining to very faint infrared limits and the total amount of light they produce. This light is much dimmer than the very dark infrared sky measured between those galaxies."

The first thing the team can see in these new images is that many galaxies that were next to or truly invisible to Hubble are bright in the images taken by Webb. These galaxies are so far away that the light emitted by stars has been stretched.

The team focused on the North Ecliptic Pole time domain field with the Webb telescope -- easily viewed due to its location in the sky. Windhorst and the team plan to observe it four times.

The first observations, consisting of two overlapping tiles, produced an image that shows objects as faint as the brightness of 10 fireflies at the distance of the moon (with the moon not there). The ultimate limit for Webb is one or two fireflies. The faintest reddest objects visible in the image are distant galaxies that go back to the first few hundred million years after the Big Bang.

For most of Jansen's career, he's worked with cameras on the ground and in space, where you have a single instrument with a single camera that produces one image. Now scientists have an instrument that has not just one detector or one image coming out of it, but 10 simultaneously. For every exposure NIRCam takes, it gives 10 of these images. That's a massive amount of data, and the sheer volume can be overwhelming.

To process that data and channel it through the analysis software of collaborators around the globe, Summers has been instrumental.

"The JWST images far exceed what we expected from my simulations prior to the first science observations," Summers said. "Analyzing these JWST images, I was most surprised by their exquisite resolution."

Jansen's primary interest is to figure out how galaxies like our own Milky Way came to be. And the way to do that is by looking far back in time at how galaxies came together, seeing how they evolved, effectively, and so tracing the path from the Big Bang to people like us.

"I was blown away by the first PEARLS images," Jansen said. "Little did I know, when I selected this field near the North Ecliptic Pole, that it would yield such a treasure trove of distant galaxies, and that we would get direct clues about the processes by which galaxies assemble and grow -- I can see streams, tails, shells and halos of stars in their outskirts, the leftovers of their building blocks."

Third-year astrophysics graduate student O'Brien designed algorithms to measure faint light between the galaxies and stars that first catch our eye.

"The diffuse light that I measured in between stars and galaxies has cosmological significance, encoding the history of the universe," O'Brien said. "I feel fortunate to start my career right now -- JWST data is like nothing we have ever seen, and I'm excited about the opportunities and challenges it offers."

Read more at Science Daily

Ecology: More than the sum of its parts

Global warming, as a component of climate change, is probably one of the best-known risks to the ecological balance of ecosystems and global biodiversity. However, ecosystems worldwide are also exposed to many other human-induced global change factors (GCFs) -- with the number and intensity of simultaneously acting factors increasing. Examples include phenomena such as light pollution, i.e. the brightening of the night sky caused by artificial light sources, or the accumulation of pesticides, such as fungicides, in the environment.

"We have a pretty clear picture of how some of these factors individually can affect parts of an ecosystem, such as a plant community. In fact, their individual impacts on a community can be quite different and even opposite," explains Benedikt Speißer, first author of the recent study and doctoral student in the laboratory of Mark van Kleunen in the Department of Biology at the University of Konstanz. What happens when an ecosystem is exposed to several of these factors simultaneously has been less well studied, although this is likely the case in most natural ecosystems.

Experiments under controlled conditions

To address this lack of knowledge, the ecologists led by Mark van Kleunen investigated how simultaneously acting GCFs affect the composition and productivity of plant communities and what role the sheer number of factors plays in this. For this purpose, they created small artificial ecological communities -- generally known as mesocosms -- consisting of nine different grasses and forbs native to Central Europe, where the selected species are widespread and often co-occur. Under controlled conditions, the researchers subsequently exposed these mesocosms to different numbers -- 0, 1, 2, 4, or 6 -- of GCFs for a duration of several weeks.

"For our experiments, we selected GCFs that do indeed often act simultaneously on an ecosystem, but differ greatly in their respective chemical and physical natures," explains van Kleunen. Besides the GCFs already mentioned -- climate warming, light pollution and fungicide accumulation -- microplastic pollution, eutrophication, which is the accumulation of nutrients in an ecosystem, and soil salinization were additional factors studied.

Quantity not quality

The researchers found that as the number of GCFs acting simultaneously increases, so does biomass production in the plant communities. "The more GCFs, the higher the probability to include a highly influential factor, such as eutrophication. In these cases, one could expect higher productivity due to the high availability of nutrients," Speißer explains. However, the researchers' analyses showed that interactions between other factors can also contribute to this effect.

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Do polar bear paws hold the secret to better tire traction?

Traction is important. Humans have been continually interested in discovering how to better move across wet or frozen surfaces safely -- whether to improve shoes for walking on sidewalks or tires to maneuver the roadways. But what makes it possible for some arctic animals to walk and run across the ice so effortlessly and gracefully without slipping and falling? Three researchers from The University of Akron (UA) took a deep dive into the paws of polar bears to find out. Their research was published in the November issue of the Journal of the Royal Society Interface.

Why polar bears?

The project team included Ali Dhinojwala, the H.A. Morton Professor of Polymer Science in the School of Polymer Science and Polymer Engineering, Nathaniel Orndorf, a 2022 Ph.D. graduate who is now employed as a senior material scientist at Bridgestone Americas, and Austin Garner, a 2021 Ph.D. graduate who is now an assistant professor of biology at Syracuse University. The project began during the height of the pandemic when things were on lockdown.

"We had an ongoing project for many years focused on ice; we were looking at the friction of materials and we were interested in this topic because we are in Akron and our national partners need to develop tires with a strong grip on the road in ice and snow conditions," said Dhinojwala. "Nate had an interest in how nature has adapted to this solution for snow. The example that came to his mind was polar bears -- and the research began from there."

The project was very interdisciplinary, combining approaches and techniques from both biological and materials research. Orndorf and Dhinojwala are polymer scientists who integrate biology into their research, while Garner is an animal biologist who integrates materials science into his research.

The idea was to look at the paw pads of polar bears. Reviewing older literature, the team discovered that previous work studied the microstructures (papillae, the little bumps on the pad of the foot) of polar bear paws and asserted that the papillae were adaptations for improved traction on snow. The previous studies did not include other species of bear so Garner helped identify two species closely related to the polar bear (the brown bear and American black bear) and one distantly related (the sun bear) to include in the study.

"The quietness of the lab during COVID gave me the opportunity to connect with a variety of scientists and environmentalists across the country," said Orndorf. "I reached out to museums, taxidermists and many others to collect and view actual samples and replicas of bear paw pads."

Orndorf and Garner then prepared the paw pad samples from the bears and imaged them using a scanning electron microscope. The team also created 3D printouts of the structures to vary diameter and height of features. They were then tested in snow in the lab to see how they reacted to the conditions.

What the team discovered was that all bears (except sun bears) have papillae on their paw pads, but that the papillae on polar bears were taller -- up to 1.5 times. And, that the taller papillae of polar bears help to increase traction on snow relative to shorter ones. Even though polar bears have smaller paw pads compared to the other species (likely because of greater fur coverage for heat conservation), the taller papillae of polar bears compensate for their smaller paw pads, giving them a 30-50% increase in frictional shear stress.

"Papillae are not unique to polar bears. Previous work [in that area] made the implicit assumption that papillae themselves are adaptations for enhanced traction on snow without studying the paw pads of other bears. It was fascinating for us to discover that the other North American bears have them as well and that the physical characteristics of the papillae are what matters for traction on snow," said Garner.

Impact on traction

Now that the research has been published, other scientists and manufacturers can look at its application to their specific projects.

"If you look at snow tires you will see that they do have some deeper treads, but this research could also show various ways to design them that could have a larger impact," said Dhinojwala.

But the interest isn't just for tire manufacturers. "Individuals who do high altitude climbing are interested in this research, companies that specialize in the delivery of goods in bad weather would love to have better grip, etc." he added.

The same experiments could also be performed on animals such as dogs, wolves, foxes and mountain goats to determine if specific snow/ice induced surface roughness profiles are present in different animals, [TE1] or if nature has evolved different surface roughness profiles in order to increase traction on ice and snow, and which profile has the best performance.

Building on past research

This isn't the first research conducted in the area of traction or grip at UA. As part of the Biomimicry Research Center (BRIC) at The University of Akron, and in collaboration with faculty members in the BRIC program, Dhinojwala and his team have examined gecko adhesion, spider silk, mussel adhesion, and structural colors inspired by birds and other organisms. His research is supported by National Science Foundation, Air Force Office of Scientific Research and Industries.

His team is continuing to look at ice -- how ice formation takes place, ice adhesion, etc. Research that is very helpful for the automotive and aircraft industries. His students have just begun working with NASA on a grant funded project in this area.

"It's exciting to give our students such interesting research projects to be part of," said Dhinojwala. "They are an asset to our team, and many go on to continue to be excellent research partners after they leave UA."

Read more at Science Daily

Serotonin 2C receptor associated with obesity and maladaptive behavior

A collaborative study involving Baylor College of Medicine, the University of Cambridge and the University of Exeter Medical School reveals a new gene associated with obesity and maladaptive behavior. The evidence shows that rare mutations in the gene for the serotonin 2C receptor play a role in the development of obesity and dysfunctional behaviors in humans and animal models. The findings, published in the journal Nature Medicine, have both diagnostic and therapeutic implications.

"Serotonin is a chemical produced in the brain that acts as a neurotransmitter, that is, it relays messages from one part of the brain to another. Serotonin communicates the message by binding to brain cells carrying serotonin receptors. These brain cells are involved in a variety of functions, including mood, appetite and some social behaviors, among others," said co-corresponding author Dr. Yong Xu, professor of pediatrics- nutrition and molecular and cellular biology at Baylor.

In the current study, the Xu lab and the lab of Dr. I. Sadaf Farooqi at the University of Cambridge, collaborated to investigate the role of one of the serotonin receptors, namely serotonin 2C receptor, in weight regulation and behavior. By combining the individual expertise of each lab -- basic and genetic animal studies in the Xu lab and human genetics in the Farooqi lab -- the team was able to make the case that serotonin 2C receptor is an important regulator of body weight and certain behaviors.

The project started with the finding that some children diagnosed with severe obesity carried rare mutations or variants of the serotonin 2C receptor gene. The researchers identified 13 different variants associated with obesity in 19 unrelated people. Further characterization of the variants revealed that 11 of them cause loss-of-function of the receptor.

"People who carried loss-of-function variants had hyperphagia, or an extreme appetite, some degree of maladaptive behavior and emotional lability, which refers to rapid, often exaggerated changes in mood including strong emotions such as uncontrollable laughing or crying or heightened irritability or temper," Xu said.

The researchers found that animal models carrying one of the human loss-of-function mutations also became obese, which confirmed the team's suspicion that loss-of-function mutations of the serotonin 2C receptor gene were involved in obesity.

"This is an important discovery from the diagnostic point of view," Xu said. "We suggest that the serotonin 2C receptor gene should be included in diagnostic gene panels for severe childhood-onset obesity."

In addition, the team identified a mechanism by which such mutations can lead to obesity. "We found that the serotonin 2C receptor is required to maintain normal firing activity of POMC neurons in the hypothalamus," Xu said. "When the receptor has a loss-of-function mutation, the firing activity of POMC neurons is impaired and as a result the animals overeat and become obese. A normal firing activity of these neurons is required to suppress overeating."

The researchers also worked with a mouse model to explore the connection between the loss-of-function mutations and behavior.

"We confirmed that having the mutation led to decreased sociability and increased aggression in mice," Xu said. "Before these findings, there was little evidence that the serotonin 2C receptor was required to maintain normal behavior and to prevent aggression. We are interested in investigating the mechanism."

At the translational level, the findings suggest that patients who develop obesity because of a loss-of-function mutation of this gene, might benefit from compounds that can bypass the deficit in the mutated receptor, such as setmelanotide, by acting directly on downstream pathways. Further studies need to be implemented to test this approach.

Read more at Science Daily

Ancient asteroid grains provide insight into the evolution of our solar system

The UK's national synchrotron facility, Diamond Light Source, was used by a large, international collaboration to study grains collected from a near-Earth asteroid to further our understanding of the evolution of our solar system.

Researchers from the University of Leicester brought a fragment of the Ryugu asteroid to Diamond's Nanoprobe beamline I14 where a special technique called X-ray Absorption Near Edge Spectroscopy (XANES) was used to map out the chemical states of the elements within the asteroid material, to examine its composition in fine detail. The team also studied the asteroid grains using an electron microscope at Diamond's electron Physical Science Imaging Centre (ePSIC).

Julia Parker is the Principal Beamline Scientist for I14 at Diamond. She said: "The X-ray Nanoprobe allows scientists to examine the chemical structure of their samples at micron to nano lengthscales, which is complemented by the nano to atomic resolution of the imaging at ePSIC. It's very exciting to be able to contribute to the understanding of these unique samples, and to work with the team at Leicester to demonstrate how the techniques at the beamline, and correlatively at ePSIC, can benefit future sample return missions."

The data collected at Diamond contributed to a wider study of the space weathering signatures on the asteroid. The pristine asteroid samples enabled the collaborators to explore how space weathering can alter the physical and chemical composition of the surface of carbonaceous asteroids like Ryugu.

The researchers discovered that the surface of Ryugu is dehydrated and that it is likely that space weathering is responsible. The findings of the study, published today in Nature Astronomy, have led the authors to conclude that asteroids that appear dry on the surface may be water-rich, potentially requiring revision of our understanding of the abundances of asteroid types and the formation history of the asteroid belt.

Ryugu is a near-Earth asteroid, around 900 metres in diameter, first discovered in 1999 within the asteroid belt between Mars and Jupiter. It is named after the undersea palace of the Dragon God in Japanese mythology. In 2014, the Japanese state space agency JAXA launched Hayabusa2, an asteroid sample-return mission, to rendezvous with the Ryugu asteroid and collect material samples from its surface and sub-surface. The spacecraft returned to Earth in 2020, releasing a capsule containing precious fragments of the asteroid. These small samples were distributed to labs around the world for scientific study, including the University of Leicester's School of Physics & Astronomy and Space Park where John Bridges, one of the authors on the paper, is a Professor of Planetary Science.

John said: "This unique mission to gather samples from the most primitive, carbonaceous, building blocks of the Solar System needs the world's most detailed microscopy, and thats why JAXA and the Fine Grained Mineralogy team wanted us to analyse samples at Diamond's X-ray nanoprobe beamline. We helped reveal the nature of space weathering on this asteroid with micrometeorite impacts and the solar wind creating dehydrated serpentine minerals, and an associated reduction from oxidised Fe3+ to more reduced Fe2+.

It's important to build up experience in studying samples returned from asteroids, as in the Hayabusa2 mission, because soon there will be new samples from other asteroid types, the Moon and within the next 10 years Mars, returned to Earth. The UK community will be able to perform some of the critical analyses due to our facilities at Diamond and the electron microscopes at ePSIC."

Read more at Science Daily