Earth

LAWRENCE -- Throughout August and early September 2019, media around the world have reported on the extensive forest fires ravaging Brazil's Amazon rainforest. Much of the concern stems from the Amazon's significance to regulating the world's climate. According to the Associated Press, the Amazon absorbs 2 billion tons of carbon dioxide every year -- about 5% of global emissions. Thus, fires in the region eat away at this carbon-absorbing capacity while at the same time adding carbon to the air through burning.

A recent study in the peer-reviewed journal Ecohydrology headed by University of Kansas researcher Gabriel de Oliveira gives important context to the fires burning big swaths of the Amazon today, most of which were set intentionally by farmers and ranchers to convert forest into land suitable for grazing animals or growing crops. The researchers sought to discover how these changes to land cover affect the exchange of water and heat between the surface of the Amazon and the atmosphere overhead.

"This is the first study to examine the biosphere-atmosphere interactions in the Amazon with such high spatial resolution satellite imagery," said de Oliveira, a postdoctoral researcher in the Department of Geography & Atmospheric Science at KU. "We tried to understand the impacts of land-cover changes and deforestation in general. When you clear-cut the forests, and you convert it either to pasture or agriculture -- or cut the forest, but for some reason don't plant anything and then have a type of vegetation called 'secondary succession' -- our idea was to try to understand how that impacts energy, like the radiative fluxes and water fluxes, or evaporation in general."

In the paper, de Oliveira and his colleagues analyzed information from both satellites in space and weather stations on the ground in the Amazon. With data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Large?Scale Biosphere?Atmosphere Experiment in Amazonia (LBA), they examined surface energy and water changes over different land?cover types in one wet year and one drought year in eastern Rondônia state, Brazil. The team also found statistically significant differences in several important measures prior to and after one year of deforestation.

"Using NASA satellite images with high spatial resolution (15m) obtained by the ASTER sensor in Rondônia state, in the south-western Brazilian Amazon, we found that deforestation and consequent transition to pasture or agriculture to grow soybean tend to increase in two to four times the soil and air temperatures in the region," de Oliveira said. "We also observed an approximately three times higher evapotranspiration over forested areas in comparison with nonforested areas."

The researchers discovered significant variances between areas on opposite sides of the Ji-Paraná River, one side of which had suffered more deforestation than the other side, located within the Jaru Biological Reserve protected area. They measured spatial variation of albedo (or the fraction of the incident sunlight that the surface reflects), net radiation (or the total energy, derived from sunlight, that's available at the surface), soil and sensible heat fluxes (or how much heat is transferred from the surface to the atmosphere), and evapotranspiration (the process by which water is transferred from the land to the atmosphere by evaporation from the soil and by transpiration from plants).

De Oliveira, who was raised in Brazil, said the rest of the world depends on the Amazon region to help moderate global climate.

"It's important because it's the largest rainforest in the world," he said. "Precipitation in the tropics, all the water fluxes that go on in the tropics, affect the whole world. The Amazon has a very important role in that. There's no other area in the world like the Amazon's unique ecosystem. It's pretty fascinating. I'm from South Brazil, a totally different environment than the Amazon. You could compare it with Kansas. But when I started studying for my master's degree, my adviser told me, 'You're going to work in the Amazon rainforest.' And I told her I'd never been there. But I spent two months in the rainforest doing research. And of course, you know, I fell in love. I'm very passionate about the Amazon and have been there so many times since then, so I have a lot of experience and stories of things that have happened there."

The KU researcher cautioned that although forest fires in the Amazon have received attention in the media this year, the fires happen to a greater or lesser degree every year.

"Fires in the Amazon happen every year during the dry season," de Oliveira said. "We have agricultural areas, areas that were deforested in the past -- but in order to clear the area for the next year, or to make the soil a little bit better for the next year, they set a fire. They claim they're only setting fire to burn agricultural lands. But sometimes the fire gets out of control, and it plays a part in more deforestation. Fires get out of control in agricultural land and reach the forest and burn the forest. But these fires happen in the Amazon every year, so it's pretty straightforward. The worst years were in 2005, 2010 and 2015 because of severe drought events. Everything was really dry, and the fires would get out of control. There are no natural fires in the Amazon. They're all set by human beings."

DALLAS - Sept. 12, 2019 - A potential treatment for polycystic kidney disease - a genetic disorder that causes the kidneys to swell with multiple cysts and can eventually lead to organ failure - has shown promising results in animal testing.

A study describing the drug's development and testing appears today in Nature Communications. The study shows an approximately 50 percent reduction in kidney size in afflicted mice following treatment. The drug is now in early clinical trials in human subjects, said Dr. Vishal Patel, Associate Professor of Internal Medicine at UT Southwestern and senior author of the study.

Autosomal dominant polycystic kidney disease (ADPKD) affects about 12 million people worldwide, with half developing end-stage kidney disease by age 60, according to the study. "Once the kidneys have failed, the only options for survival are dialysis or a kidney transplant," Dr. Patel said. "A large percentage of ADPKD patients on dialysis die each year while waiting for a donated kidney."

The only drug currently approved to treat ADPKD, called Jynarque (generic name tolvaptan), carries the FDA's highest warning in its prescribing information, a box notifying prescribers and users of the possibility of "serious and potentially fatal liver injury."

The new treatment cooperatively developed at UT Southwestern and Regulus Therapeutics Inc., a biopharmaceutical company based in California, showed no evidence of toxicity in animals or in human cell tests, according to the study. It is preferentially delivered to kidneys rather than the liver after being administered, according to the Nature Communications study.

"We earlier showed that levels of a tiny RNA fragment called microRNA-17 are increased in models of ADPKD," Dr. Patel said. "MicroRNA-17 interferes with the normal function of other, beneficial RNAs, causing kidney cysts to grow. RGLS4326, as the new drug is called in development, works by blocking the harmful microRNA-17."

Early phase one clinical trials began last year, conducted by Regulus Therapeutics. The FDA has asked for additional toxicity information from animal testing before human trials can move to the next step, Dr. Patel said.

A team of food scientists at the University of Massachusetts Amherst has developed a groundbreaking, user-friendly mathematical model for NASA to help ensure that astronauts' food remains rich in nutrients during extended missions in space.

The new research, published in the journal Food Chemistry, gives NASA a time-saving shortcut to predict the degradation of vitamins in spaceflight food over time and more accurately and efficiently schedule resupplying trips. The investigation was funded with a $982,685 grant from NASA.

"There was no information available from literature to directly answer the questions and concerns that NASA had," says senior author Hang Xiao, professor and Clydesdale Scholar of Food Science. "We used real-time, real-life data in our study to train the mathematical model and to determine how predictive and reliable the model would be."

The researchers painstakingly prepared and stored 3,000-plus pouches of spaceflight food according to the exact NASA recipes, thermal processing and storage specifications that are used for astronauts' meals on the International Space Station.

Xiao and colleagues showed for the first time how thiamine (vitamin B1) degrades over two years in three crew menu options: brown rice, split pea soup and beef brisket. Xiao says it was "quite surprising" to find that while the brown rice and split pea soup stored at 20 C demonstrated resistance to thiamine degradation, the thiamine in beef brisket was much less stable, retaining only 3 percent of the vitamin after two years.

"Proving the model was as simple as comparing these measured values from two years of storage to what was predicted as early as 12 months prior," says lead author Timothy Goulette, who was a UMass Amherst food science Ph.D. student during the study period.

The model was found to be able to predict vitamin degradation over time with "high precision," Xiao says, which will enable NASA to provide astronauts with the nutrition they need without resorting to the use of supplements.

"NASA will be able to use a minimal amount of data to quickly and accurately predict the vitamin content of a given food at any given time at a reasonable temperature," Goulette says. "The tool can be used for several applications, not just vitamins but other biological compounds."

The modeling tool will be especially important as NASA plans for the first human mission to Mars. "On their longest duration missions, the need to understand the nutritional content of their foods is paramount," Goulette explains.

The researchers note that NASA emphasizes the importance of getting nutrients from food naturally. "It's preferred for better health," Xiao says. "More and more research shows that your body handles a pill of vitamins differently from real food like pea soup."

Maintaining their nutrition through familiar food has benefits for space crews beyond their physical health, especially on longer missions, Goulette notes. "NASA wants to make sure the crew gets that psychological edge of having a connection to back home on Earth. There's a great emotional and psychological pull to food when nothing around you reminds you of home."

The UMass Amherst research team, which also included co-authors Micha Peleg, David Julian McClements, Eric Decker and Mark Normand, hypothesizes that the surprisingly higher rate of vitamin degradation in the beef may be related to the lipid oxidation of fat during thermal processing or over time.

"Different foods have different physical and chemical properties that make thiamine more or less stable," Goulette says.

LEXINGTON, Ky. (Sept. 12, 2019) - Researchers at the University of Kentucky Markey Cancer Center have made a breakthrough discovery that solves a mystery long forgotten by science and have identified a potentially novel avenue in pre-clinical models to treat non-small cell lung cancers.

Published in Cell Metabolism, the research centers on the function of glycogen accumulation in the nucleus of a cell. Glycogen is known as a carbohydrate energy storage molecule for cells. Its presence was first described in the nucleus in the 1890s, but no functional role had been described for nuclear glycogen - unlike glycogen stored by the liver or muscle tissue, which is used as a form of energy in various parts of the body.

Scientists from the UK Department of Molecular and Cellular Biochemistry, led by Ramon Sun, Ph.D., and Matthew S. Gentry, Ph.D., have discovered that human non-small cell lung cancers accumulate nuclear glycogen during the formation of tumors, providing an opportunity to finally reveal the biological role of nuclear glycogen.

"Nuclear glycogen was first reported in the 1890s and its role in cellular metabolism and impact on disease has been elusive," Sun said. "Glycogen is a storage molecule for fuel reserve, but this study demonstrates other functions of glycogen metabolism including epigenetics. Our team demonstrated that nuclear glycogen metabolism modulates the regulatory components of gene expression that are necessary for cancer progression."

While nuclear glycogen accumulation has been reported in multiple cancers, this study demonstrates that glycogen is synthesized and broken down in the nucleus, that nuclear breakdown provides the fuel for histone modifications, and that these modifications allow cells to become cancerous. Non-small cell lung cancers suppress nuclear glycogen breakdown by decreasing the amount of a key signaling molecule called malin to drive cancer progression.

"We developed a novel nuclear-specific tracer technology coupled to high-resolution mass spectrometry to trace nuclear glycogen metabolism and discovered that it modulates histone acetylation," Sun said. "We then identified the key signaling events that regulate this newly described cellular process and demonstrated its importance in pre-clinical lung cancer models."

The study provides important insights into the foundation of cell metabolism, epigenetics and cancer biology. Additionally, the work reveals possible therapeutic targets to develop future platforms for the treatment of lung cancers.

"Nuclear glycogen exists in many other cancers as well," Gentry said. "This study can open doors to other possibilities for potential anti-cancer therapies."

The study showcased a collaborative approach from a multidisciplinary team that also included Christine Brainson, Ph.D., from the UK Department of Toxicology and Cancer Biology and Dana Napier from the Biospecimen Procurement & Translational Pathology Shared Resource Facility of the UK Markey Cancer Center. The team employed innovative technologies, and the wealth of human lung cancer specimens collected at the UK Markey Cancer Center to answer the complex biological questions that encompassed this scientific question. The work was funded by the National Institutes of Health, UK Markey Cancer Center, and the American Cancer Society.

Next, Sun will further his investigations into the role of aberrant glycogen in Ewing Sarcoma. In July, he received the St. Baldrick's Scholar award for pediatric oncology research, funding work on this project at $110,000 a year for up to five years. Ewing Sarcoma is a rare bone cancer that currently affects children and young adults typically aged between 5 and 16.

Smoke from a summer wildfire is more than just an eye-stinging plume of nuisance. It's a poison to the lungs and hearts of the people who breathe it in and a dense blanket that hampers firefighting operations.

There's an atmospheric feedback loop, says University of Utah atmospheric scientist Adam Kochanski, that can lock smoke in valleys in much the same way that temperature inversions lock the smog and gunk in the Salt Lake Valley each winter. But understanding this loop, Kochanski says, can help scientists predict how smoke will impact air quality in valleys, hopefully helping both residents and firefighters alike.

Kochanski and colleagues' study appears in the Journal of Geophysical Research-Atmospheres. The work was funded by grants from the U.S. Department of Agriculture and from NASA.

Watch a video of a smoke simulation here.

Smoke screen

In 2015, firefighters battling wildfires in northern California noticed that smoke accumulating in valleys wasn't going away. The smoke got so bad that air support had to cancel flights, slowing down the firefighting effort. "That raised the question," Kochanski says, "Why is that? Why all of a sudden, is the smoke so persistent and what keeps this very thick layer of smoke in those valleys for such a long period of time?"

Kochanski and his colleagues, including researchers from the Desert Research Institute, University of Colorado, Boulder and Harvard & Smithsonian Center for Astrophysics set out to answer those questions. Their first clue came from measurements of temperature both below and above the smoke layer. The air, they found, was warmer above the smoke than below.

Residents of the Salt Lake Valley and other bowl-shaped valleys will recognize the pattern of warmer air above colder valley air as an inversion--a reversal of the normal cooling of air with altitude. The atmospheric chemistry of Salt Lake's wintertime inversions is a little different than that of a fire inversion, but the physics are the same: Warm air rises, cold air sinks and the inversion puts a warm lid over a valley, trapping all the valley air below.

The main difference is that in case of the smoke inversions the smoke layer makes the inversion even stronger.

The feedback loop 

Kochanski and his colleagues modeled the dynamics of air and smoke in valley terrain and found a feedback loop that reinforces the atmospheric inversion conditions.

"A key to this situation is the moment when the smoke appears in the atmosphere and it just does enough to block incoming solar radiation," Kochanski says. With the sun's energy blocked, the air at the ground begins to cool. "The near-surface cooling limits the mixing, enhances local inversions and leads to even higher smoke concentrations, that in turn block more solar radiation and make smoke even more persistent."

The cooling also weakens winds in the smoke-filled valley and stabilizes the atmosphere, impeding wind from breaking through and clearing out the stagnant air.

Kochanski says there are three ways out of a fire inversion. One is the settling of smoke once the fire is extinguished, allowing more light and heat to reach the ground. Another is a sufficiently large wind that can push through and mix the layers of air. A third is precipitation, as falling rain can scrub the air clean of aerosols.

"If it's business as usual and day by day you have nice sunny weather without any wind or precipitation events, well, this positive feedback loop leads to more smoke in the valleys than could be expected just based on the fire behavior alone," Kochanski says.

A new kind of forecast

Understanding the conditions that create the feedback loop help researchers predict how and when it might form or dissipate. Fire inversions will still remain a problem for firefighters, but Kochanski says that now researchers will be able to put together more accurate smoke forecasts.

"We can better tell where, how dense and how persistent the smoke is going to be," he says. "That's something that wasn't available before." Weather models will also be able to forecast air quality effects from smoke in ways they couldn't before, he adds.

The results of this study are already being integrated into the National Predictive Services Program. "When I'm talking about applications," Kochanski says. "It's not 10 years from now. It's something that we will start working on within the next couple of months."

Both rodents and humans release a bone-derived hormone called osteocalcin in response to acute stress, researchers report on September 12th in the journal Cell Metabolism. This fight-or-flight pathway is distinct from others mediated by hormones released by the adrenal glands, such as cortisol, adrenaline, and norepinephrine. The findings help to explain why patients and animals lacking cortisol and additional molecules produced by the adrenal glands can still mount the acute stress response.

"The notion that bone mediates the stress response is totally novel, as is the notion that the adrenal glands do not mediate the stress response," says senior author Gerard Karsenty of Columbia University Irving Medical Center. "This verifies the concept that bone was invented in part as a tool to fight acute danger. Clinically, it suggests that we respond to stress better when we are young and have high osteocalcin than when we are older and have much less of it."

The acute stress response, also known as the fight-or-flight response, is mediated by the sympathetic nervous system and plays a critical role in helping animals react to potentially life-threatening situations. The adrenal glands, which sit on top of the kidneys, release a variety of hormones such as adrenaline, norepinephrine, and cortisol. This triggers a cascade of wide-ranging physiological responses, including an increase in temperature, heart rate, respiration rate, blood pressure, and energy expenditure, preparing the muscles for action.

One conundrum about the acute stress response is that glucocorticoid hormones such as cortisol require hours to alter physiological responses, which seems inconsistent with the need for an immediate response to danger. "Although this certainly does not rule out that glucocorticoid hormones may be implicated in some capacity in the acute stress response, it suggests the possibility that other hormones, possibly peptide ones, could be involved," Karsenty says.

Karsenty and his colleagues suspected that bone-derived hormones could contribute to the acute stress response, based on their hypothesis that the original purpose of bone was to respond to danger. Bone protects internal organs from trauma, allows animals to move and escape danger, and mediates hearing, which is one way to detect threats. Moreover, the bone-derived hormone osteocalcin is known to increase muscle function during exercise, which is necessary for animals attempting to escape danger, and to enhance memory, which is needed in the wild to remember the locations of food and predators.

In support of this idea, Karsenty and his team found that blood levels of the bioactive form of osteocalcin, but not other bone-derived hormones, rose by 50% in mice that were restrained for 45 minutes, and by 150% 15 minutes after they received a stressful stimulus. Mice exposed to a cotton swab soaked with a component of fox urine also showed a rise in osteocalcin levels, which peaked at 2.5 minutes and remained steady for at least 3 hours. Similarly, circulating levels of bioactive osteocalcin rose in humans exposed to stress from public speaking and cross examination.

Genetic experiments in mice showed that osteocalcin was necessary for a robust increase in energy expenditure, circulating glucose, temperature, and heart rate upon exposure to stressors. Moreover, a single injection of osteocalcin was sufficient to trigger the acute stress response.

Consistent with past research on the fight-or-flight response, the stress-related surge in osteocalcin in mice depended on a brain region called the amygdala, also known as the brain's fear center. It did not, however, require the adrenal glands. "Osteocalcin could explain past observations of an intact flight-or-flight response in humans and other animals lacking glucocorticoids and additional molecules produced by the adrenal glands," Karsenty says.

Additional experiments revealed the specific chain of events. Acute stressors trigger bone-forming cells called osteoblasts to take up the neurotransmitter glutamate, released by nearby neurons present in bone, through the Glast transporter. Once inside osteoblasts, glutamate inhibits the activity of an enzyme that inactivates osteocalcin. After being released from osteoblasts, the activated hormone signals through the Gprc6a receptor to decrease the firing of upper airway and liver parasympathetic neurons involved in rest-and-digest activities. This leaves the activity of the sympathetic nervous system unopposed, triggering fight-or-flight-related physiological responses.

"The present characterization of osteocalcin as a stress hormone provides a conceptual framework that can capture most osteocalcin-regulated physiological processes," Karsenty says. "Indeed, the ability of osteocalcin to facilitate the acute stress response, favor memory, and enhance muscle function during exercise suggests that osteocalcin confers a survival advantage to bony vertebrates that live in a hostile environment such as the wild."

The authors say the findings raise the question of why cortisol rises during the acute stress response. In addition to addressing this question, they plan to expand their studies to primates and define the neuronal road map from the brain to the bone in more detailed ways.

DALLAS (SMU) - It was a puzzle about birds.

Migratory birds are known to rely on Earth's magnetic field to help them navigate the globe. And it was suspected that a protein called cryptochrome, which is sensitive to blue light, was making it possible for birds to do this.

Yet many of these animals are also known to migrate at night when there isn't much light available. So it wasn't clear how cryptochrome would function under these conditions in birds.

A new study led by UT Southwestern Medical Center in collaboration with SMU (Southern Methodist University), though, may have figured out the answer to that puzzle.

Researchers found that cryptochromes from migratory birds have evolved a mechanism that enhances their ability to respond to light, which can enable them to sense and respond to magnetic fields.

"We were able to show that the protein cryptochrome is extremely efficient at collecting and responding to low levels of light," said SMU chemist Brian D. Zoltowski, who was one of the lead authors of a new study on the findings. "The result of this research is that we now understand how vertebrate cryptochromes can respond to very low light intensities and function under night time conditions."

The study was published in the journal PNAS in September.

Cryptochromes are found in both plants and animals and are responsible for circadian rhythms in various species. In birds, scientists were specifically focused on learning more about an unusual eye protein called CRY4, which is part of a class of cryptochromes.

The lab of Joseph Takahashi, a circadian rhythms expert at UT Southwestern Medical Center, worked with other UT Southwestern scientists to purify and solve the crystal structure of the protein - the first atomic structure of a photoactive cryptochrome molecule from a vertebrate. The lab of Brian Zoltowski, an expert in blue-light photoreceptors, studied the efficiency of the light-driven reactions - identifying a pathway unique to CRY4 proteins that facilitates function under low light conditions.

"Although in plants and insects, cryptochromes are known to be photoactive, which means they react to sunlight. Among vertebrates much less is known, and the majority of vertebrate cryptochromes do not appear to be photoactive," said Takahashi, chairman of neuroscience at UT Southwestern and an investigator with Howard Hughes Medical Institute. "This photosensitivity and the possibility that CRY4 is affected by the magnetic field make this specific cryptochrome a very interesting molecule."

Researchers took a sample of the CRY4 from a pigeon and grew crystals of the protein. They then exposed the crystals to x-rays, making it possible for them to map out the location of all the atoms in the protein.

And while pigeons are not night-migratory songbirds, the sequences of their CRY4 proteins are very similar, the study noted.

"These structures allow us to visualize at the atomic scale how these proteins function and understand how they may use blue-light to sense magnetic fields," said Zoltowski, associate professor of chemistry at SMU's Dedman College of Humanities & Sciences. "The new structures also provide the first atomic level detail of how these proteins work, opening the door for more detailed studies on cryptochromes in migratory organisms."

In the study, researchers discovered unusual changes to key regions of the protein structure that can enhance their ability to collect light from their environment.

"Cryptochromes work by absorbing a photon of light, which causes an electron to move through a sequence of amino acids. These amino acids typically consist of a chain of 3 or 4 sites that act as a wire that electrons can flow through," explained Zoltowski. "But in pigeons, it was identified that this chain may be extended to contain 5 sites."

This mutation of the electron chain in pigeons makes cryptochrome less dependent on a bird's environment having a lot of light for the protein to be activated.

"Birds have evolved a mechanism to enhance the efficiency. So even when there is very little light around, they have enough signal generated to migrate," Zoltowski said.

The small but mighty flaxseed has many health benefits for humans, as well as other important uses. Yield, and therefore profits, are important for the few farmers who grow it in the United States.

After a 13-year process, a group of plant breeders has another cultivar to offer farmers. "A cultivar is a variety of a plant, created using selective breeding," explains Mukhlesur Rahman. "That means it's been bred for crop improvement and given a unique name." Rahman is an associate professor of plant sciences at North Dakota State University.

"We have bred a new flaxseed cultivar called 'ND Hammond,'" Rahman says. "It is a brown-seeded flaxseed cultivar. The average seed yield of this cultivar is higher than average compared to other flax cultivars grown in North Dakota. It is also resistant to Fusarium wilt and flax rust diseases."

Flax has several uses, from human consumption to industry use and feed purposes. The whole plant can be used.

Human consumption: Flax seeds are a common health food because of their high levels of healthy omega-3 fatty acid and easy-to-digest proteins. It's a popular addition to granola, for example.

Industry: Stems can be made into high quality plant-based fiber, similar to hemp. However, breeding for fiber strength and length is a different research avenue than breeding for seed yield.

Feed: Meal made from the plant can be fed to pets, swine, chickens, and horses as a healthy plant-based food.

Additionally, there are two types of flax seed, brown and yellow, available on the market. While both have similar levels of seed oil and omega-3 fatty acid, the yellow is sometimes preferred for "eye appeal." However, it is not as common as the brown type. Less breeding research has been put into yellow, so the yield is slightly higher in brown-seeded flax cultivars.

ND Hammond, which is a brown-seeded flax, was bred for seed yield in a very long process. It started by crossing two cultivars back in 2007. Over the years, the new cultivar was planted over and over and the best plants were selected.

Throughout the process, researchers monitored characteristics including seed yield, oil content, and visual appeal. Later, they also chose the plants most resistant to some crop diseases. They grew it at multiple sites in North Dakota to expose it to different conditions. Each time, they chose the best-performing plants. Seeds from those plants were collected to plant again to continue the selection.

"Finally, ND Hammond was released in 2018. Sufficient seeds will be available for growers to plant in 2020," Rahman says. "It took 13 years from start to finish to develop the cultivar and produce enough seed for growers. Most people don't realize the process takes this long."

Where did the name ND Hammond come from? ND stands for North Dakota, which is responsible for 92% of U.S. seed flax production. Hammond is in honor of an influential flax breeder at North Dakota State who made all crosses to develop the cultivar.

MINNEAPOLIS - Even before a dementia diagnosis, people with mild cognitive impairment may have different changes in the brain depending on what type of dementia they have, according to a study published in the September 11, 2019, online issue of Neurology®, the medical journal of the American Academy of Neurology.

"These differences may reflect underlying changes in the brain that could be used to track early changes in people who are going to develop either Alzheimer's disease or dementia due to cerebrovascular disease," said study author Juan "Helen" Zhou, PhD, of Duke-NUS Medical School in Singapore and a member of the American Academy of Neurology.

The study involved people recruited from Samsung Medical Center in South Korea: 30 people with mild cognitive impairment including memory problems, which is often considered an early stage of Alzheimer's disease, and 55 people with mild cognitive impairment with damage to small blood vessels in the brain, which is an early sign of vascular dementia, or dementia due to cerebrovascular disease.

The participants had positron emission tomography (PET) scans at the start of the study to see if they had amyloid-beta plaques in the brain that are associated with Alzheimer's disease, and structural MRI scans to see if they had the signs of cerebrovascular disease associated with vascular dementia. The functional MRI scans were used to measure how brain regions are functionally connected. These scans were repeated every year for up to four years.

The functional MRI scans were looking at functional networks in the brain--the executive control network, which is engaged during activities such as use of working memory and switching between tasks; and the default mode network, which has been linked to memory retrieval.

The researchers found that the interactions in the default network declined more steeply over time in the people who had amyloid-beta plaques in the brain confirming Alzheimer's disease than in people in early stages of vascular dementia and without amyloid-beta plaques in the brain. Specifically, the rate of annual decline in the default mode network connections was on average 13.6 times faster in the people who had amyloid-beta plaques in the brain confirming Alzheimer's disease than in people in the early stages of vascular dementia and without amyloid-beta plaques.

Researchers also found that the rate of annual increase in interactions in the executive control network was on average three times faster in people in the early stages of vascular dementia and without amyloid-beta plaques than in people in the early stages of Alzheimer's disease.

"More studies are needed with larger numbers of participants and longer follow-up periods, but these results suggest that these changes in brain network connections could potentially be used to track early changes in Alzheimer's disease and cerebrovascular disease," said study author Sang Won Seo, MD, of Samsung Medical Center in South Korea.

Limitations of the study were the small number of participants and the relatively short time for follow-up.

In western lowland gorillas, groups consist of several females and only one adult male, the silverback. With his impressive body size, he protects his group against predators and other adult males. Females rely on this protection and never travel alone, however they may change groups multiple times during their lives. "Female gorillas seem to have different strategies when it comes to reproduction and transfer", says Marie Manguette, first author of the study. "We have observed females transferring to another group after every weaned offspring and therefore up to six times in their lives, while others have stayed and bred with the same male for 20 years."

Manguette and her colleagues found that a high percentage of infants die if they are born when the male is old and has reached the end of his reproductive years. "When a silverback dies, all females leave to join a new male", says Manguette. "If at that point a female has a suckling infant, the new silverback will most likely kill it to breed with the female right away and raise his own offspring." Female lowland gorillas can prevent this from happening by transferring to a new group right after her offspring stops suckling, leaving the infant behind with its father.

Yet when females leave to join another male, they have longer intervals between births and hence fewer births over their lifetime. These delays can be substantial: females that transferred four times during their life took approximately ten years longer to produce a surviving offspring compared to females that never transferred. "Given the high costs of transfer, a female finds herself in a dilemma when she is with an older male: does she stay, breed with him again and risk losing the infant if he dies, or does she leave and suffer the reproductive costs", says Manguette.

The study shows that females suffer the highest cost if they lose an offspring. "Therefore females should leave a male if they fear he is weak and will not survive long enough for her to carry and wean a new infant." Yet how do females know when to leave? "Many females leave a male long before he dies, suggesting that they may be able to determine when he is getting weaker, potentially using the outcome of aggressive displays between males when they meet as a hint", says Manguette. "Whether females really leave an old male to transfer to a younger and stronger male still remains to be determined, but our results suggest that they should."

The authors further emphasize the importance of long-term studies for the understanding of slow reproducing species such as gorillas. The information they provide on the live and behavior of gorillas is desperately needed to improve conservation efforts for this threatened species. "We need to do whatever it takes to protect these endangered animals in their natural habitat before it is too late", say the authors.

"This study of a long-term data set from wild gorillas contributes to our understanding of the costs and benefits of social living. Male and females form long term social bonds and can live together for long periods of time. This study sheds light on the mechanisms driving the grouping patterns in gorillas and the dynamic nature of their social groups, which in turn, contributes to our understanding of human sociality", says Martha Robbins, senior author of the study.

A new study from researchers at the Johns Hopkins Bloomberg School of Public Health found that adolescents who spend more than three hours a day on social media are more likely to report high levels of internalizing behaviors compared to adolescents who do not use social media at all.

The study, published online September 11 in JAMA Psychiatry, examined the time adolescents reported spending on social media and two types of behaviors that can be indicators of mental health problems: internalizing and externalizing. Internalizing can involve social withdrawal, difficulty coping with anxiety or depression or directing feelings inward. Externalizing can include aggression, acting out, disobeying or other observable behaviors.

The study found the use of social media for any amount of time was associated with both a greater risk of reporting internalizing problems alone and concurrent symptoms of both internalizing and externalizing problems. The study found no significant association with social media use and externalizing problems alone. Teens who spent at least three hours on social media a day had the greatest risk for reporting internalizing problems alone.

"Many existing studies have found a link between digital or social media use and adolescent health, but few look at this association across time," says lead author Kira Riehm, MSc, a doctoral student in the Department of Mental Health at the Bloomberg School. "Our study shows that teens who report high levels of time spent on social media are more likely to report internalizing problems a year later. We cannot conclude that social media causes mental health problems, but we do think that less time on social media may be better for teens' health."

Social media use among teens is widespread. Recent polls have found that 95 percent of teens in the U.S. have access to a smartphone and close to 75 percent of teens have at least one social media account. The use of social media has both health risks and benefits. These platforms often provide ways to connect with peers and information and resources on causes important to them, but there are risks of cyberbullying and other digital aggressions.

For their study, the researchers used a nationally representative sample of U.S. adolescents ages 13 to 17 from the federally funded Population Assessment of Tobacco and Health Study (PATH) between 2013 and 2016. The study collected data over three years and the analysis involved 6,595 respondents. Each year, participants were asked how much time they spent on social media as well as questions pertaining to symptoms of internal and external mental health problems.

The study found that less than 17 percent of adolescents did not use social media. For those who did report using social media, 2,082 or 32 percent, reported spending less than 30 minutes; 2,000, or about 31 percent, reported spending 30 minutes to three hours; 817, or 12 percent, reported spending three to six hours; and 571, or 8 percent, reported spending more than six hours per day.

Researchers also found that 611 respondents, or about 9 percent, reported experiencing only internalizing problems, while 885, or 14 percent, reported experiencing externalizing problems only; 1,169, or about 18 percent, reported experiencing both internal and external problems; and 3,930, or about 59 percent, reported no/low problems. The study found no links between social media use and mental health problems and gender.

"Social media has the ability to connect adolescents who may be excluded in their daily life. We need to find a better way to balance the benefits of social media with possible negative health outcomes," says Riehm. "Setting reasonable boundaries, improving the design of social media platforms and focusing interventions on media literacy are all ways in which we can potentially find this equilibrium."

An evolution revolution has begun after scientists extracted genetic information from a 1.7 million-year-old rhino tooth - the largest and oldest genetic data to ever be recorded.

Researchers identified an almost complete set of proteins, a proteome, in the dental enamel of the rhino and the genetic information discovered is one million years older than the oldest DNA sequenced from a 700,000-year-old horse.

The findings by scientists from the University of Copenhagen and St John's College, University of Cambridge, are published today (September 11) in Nature. They mark a breakthrough in the field of ancient biomolecular studies and could solve some of the biggest mysteries of animal and human biology by allowing scientists to accurately reconstruct evolution from further back in time than ever before.

Professor Enrico Cappellini, a specialist in Palaeoproteomics at the Globe Institute, University of Copenhagen, and first author on the paper, said: "For 20 years ancient DNA has been used to address questions about the evolution of extinct species, adaptation and human migration but it has limitations. Now for the first time we have retrieved ancient genetic information which allows us to reconstruct molecular evolution way beyond the usual time limit of DNA preservation.

"This new analysis of ancient proteins from dental enamel will start an exciting new chapter in the study of molecular evolution."

DNA data that genetically tracks human evolution only covers the last 400,000 years. But the lineages that led to modern humans and to the chimp - the living species genetically closest to humans - branched apart around six to seven million years ago which means scientists currently have no genetic information for more than 90 per cent of the evolutionary path that led to modern humans.

Scientists also don't know what the genetic links are between us and extinct species such as Homo erectus - the oldest known species of human to have had modern human-like body proportions - because everything that is currently known is almost exclusively based on anatomical information, not genetic information.

Researchers have now used ancient protein sequencing - based on ground-breaking technology called mass spectrometry - to retrieve genetic information from the tooth of a 1.77 million year old Stephanorhinus - an extinct rhinoceros which lived in Eurasia during the Pleistocene. Researchers took samples of dental enamel from the ancient fossil which was discovered in Dmanisi, Georgia, and used mass spectrometry to sequence the ancient protein and retrieved genetic information previously unobtainable using DNA testing.

Tooth enamel is the hardest material present in mammals. In this study researchers discovered the set of proteins it contains lasts longer than DNA and is more genetically informative than collagen, the only other protein so far retrieved from fossils older than one million years.

Professor Jesper V. Olsen, head of the Mass Spectrometry for Quantitative Proteomics Group at the Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, and co-corresponding author on the paper, said: "Mass spectrometry-based protein sequencing will enable us to retrieve reliable and rich genetic information from mammal fossils that are millions of years old, rather than just thousands of years old. It is the only technology able to provide the robustness and accuracy needed to sequence tiny amounts of protein this old."

Professor Cappellini added: "Dental enamel is extremely abundant and it is incredibly durable, which is why a high proportion of fossil records are teeth.

"We have been able to find a way to retrieve genetic information that is more informative and older than any other source before, and it's from a source that is abundant in the fossil records so the potential of the application of this approach is extensive."

Lead author on the paper Professor Eske Willerslev, who holds positions at St John's College, University of Cambridge, and is director of The Lundbeck Foundation Centre for GeoGenetics, Globe Institute, Faculty of Health and Medical Sciences, at the University of Copenhagen, said: "This research is a game-changer that opens up a lot of options for further evolutionary study in terms of humans as well as mammals. It will revolutionise the methods of investigating evolution based on molecular markers and it will open a complete new field of ancient biomolecular studies."

This rearranging of the evolutionary lineage of a single species may seem like a small adjustment but identifying changes in numerous extinct mammals and humans could lead to massive shifts in our understanding of the way the world has evolved.

The team of scientists is already implementing the findings in their current research. The discovery could enable scientists across the globe to collect the genetic data of ancient fossils and to build a bigger, more accurate picture of the evolution of hundreds of species including our own.

Coasts, oceans, ecosystems, weather and human health all face impacts from climate change, and now valuable soils may also be affected.

Climate change may reduce the ability of soils to absorb water in many parts of the world, according to a Rutgers-led study. And that could have serious implications for groundwater supplies, food production and security, stormwater runoff, biodiversity and ecosystems.

The study is published in the journal Science Advances.

"Since rainfall patterns and other environmental conditions are shifting globally as a result of climate change, our results suggest that how water interacts with soil could change appreciably in many parts of the world, and do so fairly rapidly," said co-author Daniel Giménez, a soil scientist and professor in the Department of Environmental Sciences at Rutgers University-New Brunswick. "We propose that the direction, magnitude and rate of the changes should be measured and incorporated into predictions of ecosystem responses to climate change."

Water in soil is crucial for storing carbon, and soil changes could influence the level of carbon dioxide in the air in an unpredictable way, according to Giménez, of the School of Environmental and Biological Sciences. Carbon dioxide is one of the key greenhouse gases linked to climate change.

Giménez co-authored a study published in the journal Nature last year showing that regional increases in precipitation due to climate change may lead to less water infiltration, more runoff and erosion, and greater risk of flash flooding.

Whether rainfall will infiltrate or run off of soil determines how much water will be available for plants or will evaporate into the air. Studies have shown that water infiltration to soil can change over one to two decades with increased rainfall, and climate change is expected to boost rainfall in many areas of the world.

During a 25-year experiment in Kansas that involved irrigation of prairie soil with sprinklers, a Rutgers-led team of scientists found that a 35 percent increase in rainfall led to a 21 percent to 33 percent reduction in water infiltration rates in soil and only a small increase in water retention.

The biggest changes were linked to shifts in relatively large pores, or spaces, in the soil. Large pores capture water that plants and microorganisms can use, and that contributes to enhanced biological activity and nutrient cycling in soil and decreases soil losses through erosion.

With increased rainfall, plant communities had thicker roots that could clog larger pores and there were less intense cycles of soil expansion when water was added or contraction when water was removed.

The next step is to investigate the mechanisms driving the observed changes, in order to extrapolate the findings to other regions of the world and incorporate them into predictions of how ecosystems will respond to climate change. The scientists also want to study a wider array of environmental factors and soil types, and identify other soil changes that may result from shifts in climate.

Bottom Line: Adolescents who spend more than three hours a day using social media may be at higher risk for mental health problems. This observational study included a nationally representative sample of nearly 6,600 U.S. adolescents (ages 12-15) who reported time spent on social media during a typical day and who reported information about mental health problems. After accounting for factors including a history of mental health problems, study authors report that adolescents who used social media more than three hours a day were more likely to report internalizing problems (these can include depression, anxiety and loneliness), as well as symptoms of both internalizing and externalizing (such as aggression and antisocial behavior) problems but not externalizing problems alone compared with adolescents who reported no social media use. Limitations of the study include that time spent on social media and information about internalizing and externalizing problems were self-reported, and other factors not accounted for by study authors may help to explain the results.

Authors: Kira E. Riehm, M.S., Johns Hopkins University, Baltimore, and coauthors.

(doi:10.1001/jamapsychiatry.2019.2325)

Editor's Note: The article includes conflict of interest and funding/support disclosures. Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.

A team of geneticists with a desire to understand the inner workings of genes implicated in cellular identity has discovered new biological targets that may help devise alternative therapies for cancers that are becoming resistant to existing drugs.

First discovered in fruit flies, Polycomb genes were initially studied due to their essential roles in development and their role in regulating cellular identity. They are central to the field of epigenetics, which strives to explain how many cells in our bodies - with identical sets of genes - look and behave so differently.

In 2011 scientists discovered that a particular Polycomb gene, called EZH2, is mutated in lymphomas, a cancer of immune cells. Benefiting from knowledge derived from many years of curiosity-driven scientific research, several companies soon developed drugs to inhibit the activity of EZH2. These targeted treatments are now showing real promise in clinical trials.

However, as with many cancer therapies, resistance has begun to arise, which means scientists will need to develop alternative strategies to fight the cancerous cells. The new discovery provides some new clues as to how this might be achieved and offers another real-life example of how curiosity-driven research can provide vital insights.

Associate Professor in Genetics at Trinity College Dublin, Adrian Bracken, led the team that has just published its findings in the leading international scientific journal, Molecular Cell. Irish Research Council PhD Fellow in Professor Bracken's lab, Dr Evan Healy, is lead author on the paper, which was published in parallel with another study conducted by researchers at the Memorial Sloan Kettering Cancer Centre.

Both research teams discovered that EZH2 requires additional "accessory components" to target its activity to key regions in the genome and execute its critical cellular functions. Importantly, the new results suggest these "accessory components" represent very promising alternative targets, which will be needed for oncologists to treat patients who develop resistance to existing EZH2 inhibitor drugs.

Commenting on the findings, Professor Bracken said: "This new discovery was driven purely by our curiosity to understand how Polycombs regulate cellular identity, but we also anticipate that it will lead to new opportunities to develop alternative treatments for patients with cancers driven by mutations in EZH2 and its related genes."

"We are extremely grateful for funding support from the Irish Research Council Advanced Laureate programme and Science Foundation Ireland, without which this research would not have been possible."

Commenting on the achievements of Professor Bracken's team, Director of the Irish Research Council, Peter Brown, said: "Earlier this year, the Irish Research Council announced a game-changing investment of €11.8 million in open frontier research to fund 12 researchers under our Advanced Laureate Awards programme. Adrian Bracken was one of those researchers, while members of his team are also availing of supports through other Irish Research Council programmes. We are delighted to support Adrian and his team to conduct ground-breaking research which is pushing out the boundaries of our understanding. The article in Molecular Cell, a leading journal in the field, reflects the calibre and significance of the research being done."