Culture

New Brunswick, NJ--Children and adolescents with multisystem inflammatory syndrome in children (MIS-C) who are treated initially with intravenous immune globulin (IVIG) and glucocorticoids have reduced risk for serious short-term outcomes, including cardiovascular dysfunction, than those who receive an initial treatment of IVIG alone, a new study finds.

MIS-C is a rare but serious--and sometimes fatal--condition associated with COVID-19, in which different body organs or systems become inflamed, including the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal system. It can occur weeks after having COVID-19 and even if the child or caregivers did not know the child had been infected.

The new study, published in the New England Journal of Medicine, analyzed treatment and outcomes of more than 596 children and adolescents who had been admitted with MIS-C to one of 58 U.S. hospitals between March 15 and Oct. 31, 2020, in the hopes of providing data that could guide MIS-C treatment in the future, study authors noted.

"It is important to realize that MIS-C is still a new disease process in its infancy, and this is the first large-scale article published looking at treatment options and patient outcomes," said Dr. Steven M. Horwitz, assistant professor of pediatrics in the Division of Pediatric Critical Care at Rutgers Robert Wood Johnson Medical School, and one of the authors of the study. "At our own institution, we have seen an evolution of the initial work-up and treatment of MIS-C over the past year, and a relatively large study such as this will help guide future treatment options."

Study findings showed that, while nearly a third (31%) of children and adolescents treated with IVIG alone experienced new or persistent cardiovascular dysfunction on the second day of treatment or later, that number dropped to 17% for patients whose initial therapy combined IVIG and glucocorticoids. In addition, IVIG and glucocorticoids as initial treatment required less adjunctive therapy on or after the first day of treatment than those who were initially treated with IVIG alone: 34% compared to 70%.

IVIG is a highly concentrated, diverse group of antibodies, delivered through the vein, that is used either to bolster an individual's own antibodies if they are immunodeficient or, as in the case of MIS-C, to help the body defend against an attack on its cells by its own immune system. It is a standard treatment for Kawasaki's disease, which has similarities to MIS-C, and viral myocarditis. Glucocorticoids, meanwhile, are steroid hormones that help suppress inflammation from autoimmune disorders; they include methylprednisolone (prescribed to 68% of those studied who received glucocorticoids), prednisolone and dexamethasolone.

The study's findings regarding treatment outcomes are particularly important given the ongoing issues related to the COVID-19 pandemic, noted Dr. Horwitz.

"While vaccines have played a massive role in reducing the spread of COVID, we are all aware that COVID and MIS-C are not going away anytime soon," he said. "We are now seeing new variants with higher transmission rates and less protection from the vaccines. As such, we expect to keep seeing MIS-C."

While MIS-C is a very serious condition that should not be taken lightly, they have seen the majority of patients do very well, Dr. Horwitz added: "Although MIS-C by definition affects multiple organ systems, the cardiac dysfunction--including arrhythmias, dilated coronary arteries and decreased function--continues to be the biggest concern. With effective treatment, these patients tend to improve in a timely manner and quicker than what we have historically seen with other forms of viral myocarditis."

The new study was funded by the Centers for Disease Control and Prevention under a contract to Boston Children's Hospital as part of the Overcoming COVID-19 surveillance registry, designed to track COVID-19-related severe complications in children and adolescents hospitalized in the United States. Specialists from Robert Wood Johnson Medical School's Department of Pediatrics and The Bristol-Myers Squibb Children's Hospital at Robert Wood Johnson University Hospital are among the Overcoming COVID-19 investigators.

"I give credit to the CDC and Boston Children's Hospital in helping lead this effort. One of the key aspects of this work has been our ability to come together as a pediatric medical community, to collaborate and share information about this new and evolving disease," Dr. Horwitz said.

That understanding involves not only MIS-C as an acute illness, but also long-term follow-up, he added.

"We are not sure if MIS-C is 'just the tip of the iceberg,'" Dr. Horwitz explained. "While most patients with MIS-C recover relatively quickly, we don't know the long-term effects that this disease may carry. Are patients who have had MIS-C prone to developing similar symptoms in the future? Is it safe for patients who have had MIS-C to receive the COVID vaccine? Are there certain genetic predispositions that make people more susceptible to developing MIS-C? These are just some of the questions that we are continuing to study."

Taken together, the bacteria, viruses, fungi and other microbes that live in our intestines form the gut microbiome, which plays a key role in the health of people and animals. In new research from the University of Minnesota, University of Notre Dame and Duke University, scientists found that genetics nearly always plays a role in the composition of the gut microbiome of wild baboons.

"In humans, research has shown that family members share a significant portion of microbes in their gut, but it's hard to answer if our microbiome is shaped more by nature, such as those we inherit from our family, or nurture, such as the similar diets, environments and behaviors families share," said lead author Laura Grieneisen, a postdoctoral fellow in the College of Biological Sciences. "Many human diseases and other markers of health have a genetic component. The number and types of bacteria in the gut are no different. By understanding the heritability of the gut microbiome will help us better link genes, the gut and health."

To examine consistent data, researchers turned to more than 16,000 microbiome samples collected from 585 wild baboons over the course of 14 years. The size and generational scope of this microbiome data -- crucial for understanding how the microbiome is affected by genetics (i.e. microbiome heritability) -- has not yet been collected in humans.

In the research, published in the journal Science, the team tested how host traits (e.g., age, sex), behaviors (e.g., social group membership, grooming), diet, pedigree relatedness, and environmental characteristics (e.g., season, year) predicted 1,034 gut microbiome traits.

Researchers found that:

while prior research in humans indicated that heritable gut microbiome taxa (i.e., species, family and class of an organism) were uncommon, 95% of microbial taxa were heritable in the wild baboon population;

heritability estimates are strongly and positively correlated between humans and baboons, suggesting that traits with low heritability in baboons may also be heritable -- but have gone undetected -- in humans;

microbiome heritability is dynamic and context-dependent, such that heritability is greater in the dry season, with low diet diversity, and in older hosts.

"Our results qualitatively change the field's perspective on the determinants of microbiome composition," said co-author Ran Blekhman, an associate professor in the College of Biological Sciences. "From one in which the host genotype plays no role in the majority of microbiome taxa to one in which the host genotype nearly always plays a role. As a result, microbiome traits might evolve via natural selection on the host."

Researchers state that this opens the door to identifying individual microbes that are particularly shaped by host genetics.

"As a result, if there are microbes that are heritable and linked to health outcomes, it would allow us to better understand the genetic basis of these outcomes," said Grieneisen. "Most of the microbiome may be visible to natural selection on the host genome."

The researchers add that their results are consistent with past work: although the role of a host's genotype is universal, their environment and behaviors are still much more important than genetics in shaping microbiome composition. The team will continue to work with the wild baboon dataset to pursue questions about the drivers and physiological consequences of long-term changes in the microbiome.

This research was supported by funding from the National Institutes of Health, the University of Minnesota Grand Challenges Biology Postdoctoral

A team led by researchers at Baylor College of Medicine found that a screening method known as untargeted metabolomics profiling can improve the diagnostic rate for inborn errors of metabolism, a group of rare genetic conditions, by about seven-fold when compared to the traditional metabolic screening approach.

The study, published in JAMA Network Open, shows that untargeted metabolomics identifies many more disorders of greater variety as compared to traditional methods, including disorders for which there was not a clinically available biochemical test. The researchers hope that adoption of metabolomics to screen for inborn errors of metabolism will result in a more rapid, more efficient and less expensive diagnostic journey for individuals and families with rare metabolic disorders.

"Currently, newborn screening is conducted in every infant born in the U.S. to check for serious but rare health conditions at birth. Screening includes blood, hearing and heart tests," said corresponding author Dr. Sarah Elsea, professor of molecular and human genetics at Baylor and senior director of biochemical genetics at Baylor Genetics. "While newborn screening in general has improved in the last 10 years, clinically screening for inborn errors of metabolism has not changed substantially in the last 40 to 50 years."

Inborn errors of metabolism include conditions that disrupt the normal processes the body uses to transform food into energy and can result in serious conditions. Having an early diagnosis can lead to early treatment, when available. For instance, newborn screening looks for signs of conditions such as phenylketonuria, the body's inability to break down the amino acid phenylalanine, which results in its accumulation. Buildup of phenylalanine can irreparably harm the nervous system, but early intervention may help manage the condition.

"We developed a clinical test - untargeted metabolomics profiling - that looks at a broader range of metabolic compounds in the blood, therefore screening for many more disorders than the currently used approach," said Elsea, a member of Baylor's Dan L Duncan Comprehensive Cancer Center and Center for Drug Discovery. "In the current study, we compared the standard approach and untargeted metabolomics on their effectiveness identifying metabolic conditions."

The researchers compared the results of applying the two approaches to 4,464 clinical samples received from 1,483 unrelated families. They found that the traditional standard analysis has a positive rate of diagnosis of about 1%. However, using the untargeted metabolomics analysis the researchers were able to confirm a positive rate of diagnosis of 7%.

"This is a substantial increase in the ability to diagnose these conditions," Elsea said. "We are now able to identify in one blood sample more conditions than ever before."

"In addition, our analysis of many metabolic compounds in a single blood sample reduces the need of having to take more samples to do further testing looking for specific conditions. This includes taking samples of cerebrospinal fluid, which involves a more invasive procedure than drawing a blood sample," said co-author Dr. V. Reid Sutton, professor of molecular and human genetics at Baylor, medical director of the biochemical genetics laboratory at Baylor Genetics and director of the Inborn Errors of Metabolism Service at Texas Children's Hospital.

This screening approach offers the critical advantages of reducing the time to having a diagnosis and starting treatment, if available.

Using untargeted metabolomics in combination with genetic screening enables researchers and physicians not only to confirm a diagnosis with high degree of confidence, but also to rule out potential conditions. The novel, broader screening approach identifies severe forms of diseases and also mild forms that may not quite fit the characteristics observed in the more severe cases.

"We are finding individuals with milder forms of a disease are more common in our populations than those with severe forms," Elsea said. "Our approach has been quite successful identifying seizure disorders, movement disorders and autism spectrum disorders. Our analyses have taught us to open our minds to a much greater spectrum of disease, allowing us to improve early diagnosis."

The sharp eyes of an eagle, the extraordinary hearing of an owl - to successfully find food, the eyes and ears of birds have adapted optimally to their living conditions. Until now, the sense of smell has played a rather subordinate role. When meadows are freshly mowed, storks often appear there to search for snails and frogs. Researchers at the Max Planck Institute for Animal Behavior in Radolfzell and the Max Planck Institute for Chemistry in Mainz have now studied the birds' behavior and discovered that the storks are attracted by the smell of the mown grass. Only storks that were downwind and could thus perceive the smell reacted to the mowing. The scientists also sprayed a meadow with a spray of green leaf scents released during mowing. Storks appeared here as well. This shows that white storks use their sense of smell to forage and suggests that the sense of smell may also play a greater role in other birds than previously thought.

For farmers around Lake Constance, it's a familiar sight: when they start mowing their meadows, storks often appear next to the tractors as if out of nowhere. The white storks live in the wet areas around the lake, feeding on snails, frogs and small rodents that find shelter in high meadows. If these meadows are mowed, the small animals are easy prey. However, the storks do not always appear when mowing takes place. Until now, it was not known how the storks locate the rich food source.

Previously, it was believed that birds relied primarily on their eyes and ears rather than their sense of smell. "It was simply assumed that birds can't smell well because they don't have real noses," says Martin Wikelski, director at the Max Planck Institute of Animal Behavior. "Yet they have a very large olfactory bulb in the brain with many receptor molecules for scents." So birds have the best prerequisites for a fine nose.

Testing for smell

Wikelski has spent many years observing storks and researching their migratory behavior, among other things. When he talked to his colleague Jonathan Williams about the storks' puzzling reaction to mowed meadows, Williams had an idea. Williams works at the Max Planck Institute for Chemistry in Mainz, Germany, studying volatile organic compounds and their effects on humans and the environment. "My guess was that the storks were reacting to the intense smell of freshly cut grass," Williams says. This typical smell is produced by so-called green leaf odorants and consists of only three different molecules. "These are also added to perfumes, for example, to give them a fresh, "green" note," explains Williams.

The researchers now wanted to find out whether the sense of smell actually leads the storks to freshly mown meadows. To do this, they monitored the birds' movements both from aircraft and via GPS sensors of tagged animals. "We first had to rule out the possibility that the storks could hear the tractor or see the mowing process," Wikelski says. Therefore, they only included storks in the observation that were more than 600 meters away from the mowed meadow and did not have direct visual contact. The researchers also made sure that the storks were not alerted to the mowing process by the behavior of conspecifics or other birds.

Direction downwind

When mowing began, only the storks that were downwind flew to the meadow in question. The conspecifics that were upwind and thus could not perceive the grass smell did not react. To test whether the smell of the cut grass alone attracted the storks, the researchers switched to a meadow that had been mowed two weeks earlier. "The grass of this meadow was still very short. Therefore, it is uninteresting for the storks to forage," Wikelski explained. On this meadow, he and colleagues spread grass that had been mowed a short time before at a greater distance. A short time later, the first storks flew in and searched for food in the mown grass.

The researchers finally mixed a solution of green leaf scents and sprayed it on a meadow with short grass. The meadow then smelled intensely of mown grass and also attracted storks from the surrounding area. "This proves that storks find their way to feeding sites via scents in the air," Williams says.

This finding contradicts the previous assumption that storks primarily use their eyes to find food. Rather, the birds rely on their sense of smell to do so. "There have been storks that have flown more than 25 kilometers from the other side of Lake Constance to mowed meadows," Wikelski says. The researchers suspect that the sense of smell may also play a greater role than previously thought in the foraging activities of other bird species. Birds of prey such as buzzards and red kites are regularly observed flying over freshly mown meadows.

The function of a protein can depend on its abundance in a cell. So, when investigating the properties of a new protein, it is essential to make sure that the same amount is produced by every cell. Researchers at Baylor College of Medicine and Rice University have found a new way to do just that through the creation of new genetic circuits called Equalizers.

The findings, in the current edition of Nature Communications, show how researchers engineered these genetic circuits to buffer protein output from variations in the number of copies of the gene inside the cell, thereby helping to create consistent protein expression. This property is called "gene dosage compensation."

The researchers use an analogy of heating a house to help explain how Equalizers work. Imagine using randomly placed space heaters to heat your home. To ensure each room gets a heater you would purchase some extra ones, but that would mean some rooms might have extra heaters. Those rooms might be too hot, so a solution would be to have thermostats on each heater to downregulate the heat when a room becomes too hot. Those thermostats act as the Equalizer.

Researchers typically encode genes to be expressed on circular pieces of DNA called plasmids. Excess plasmids are often used to ensure that most cells get one, but some cells will get several. The Equalizer is composed of transcriptional negative feedback and post-transcriptional incoherent feedforward loops. These loops counteract the presence of extra plasmids: they sense the outputs, in this case the proteins and mRNAs that the plasmids produce, and tune down their expression if they rise too high.

"We didn't invent the parts, but rather we invented a new way to connect them together into a circuit," said Jin Yang, who shared co-first authorship of the paper with graduate student Jihwan Lee of Rice University. Jin was a bioengineering undergrad at Rice University while developing this work and currently is a Ph.D. student at the Massachusetts Institute of Technology. "In natural systems, some gene networks must control gene dosage variation to remain functional and conserve their properties.

We repurposed and combined two types of gene dosage compensation circuits to create a version that enables uniform expression of any protein scientists want to produce in the lab."

Negative feedback and incoherent feedforward circuit subcircuits can each help compensate for gene dosage, but the researchers found that coupling the two improved overall performance. This is because each circuit is not perfect. For example, the incoherent feedforward loop can saturate because it requires other proteins that are present in limited quantities in the cell. The negative feedback loop is limited in its inhibitory capacity, similar to a leaky sink faucet that cannot be fully closed. But combining these two imperfect circuits produced robust performance, with each circuit helping mitigate the limitation of the other.

"The process we used for these findings was a collaborative effort bringing together computer simulations and biology. This is similar to how engineers work - they draw up their plans, create a model and then build their structure," said Dr. Oleg Igoshin, professor of bioengineering, of biosciences and of chemistry at Rice University and a senior author on the paper. "In this case we were able to create our model and show the effectiveness through computational models before it was then synthetically engineered in the lab."

But why is minimizing expression variation important when it comes to biological research?

"The effect of a protein can depend on its abundance in a cell. If you're studying a new protein and its concentration is too low, you may not be able to observe its function in the cell. If its concentration is too high, the protein may mislocalize, aggregate, produce cytotoxicity or otherwise produce responses that are not physiological. It is therefore important that a protein is expressed at the desired level in every cell under investigation," said Dr. François St-Pierre, assistant professor of neuroscience and McNair Scholar at Baylor and corresponding author of this study. "We believe Equalizers will be of high value both for basic research and for industry."

Maunakea, Hawai'i - Astronomers have made the rare sighting of two stars spiraling to their doom by spotting the tell-tale signs of a teardrop-shaped star.

The tragic shape is caused by a massive nearby white dwarf distorting the star with its intense gravity, which will also be the catalyst for an eventual supernova that will consume both. Found by an international team of astronomers and astrophysicists led by the University of Warwick, it is one of only a very small number of star systems discovered that will one day see a white dwarf star reignite its core.

The team's new research is published in today's issue of the journal Nature Astronomy.

With the help of W. M. Keck Observatory on Maunakea in Hawai'i, the astronomers were able to confirm that the two stars are in the early stages of a spiral that will likely end in a Type Ia supernova - a type that helps astronomers determine how fast the universe is expanding.

The couple - a binary star system called HD265435 - is located roughly 1,500 light-years away; it is comprised of a hot subdwarf star and a white dwarf star orbiting each other closely at a dizzying rate of around 100 minutes. White dwarfs are 'dead' stars that have burned all their fuel and collapsed in on themselves, making them small but extremely dense.

A type Ia supernova is generally thought to occur when a white dwarf star's core reignites, leading to a thermonuclear explosion. There are two scenarios where this can happen. In the first, the white dwarf gains enough mass to reach 1.4 times the mass of our Sun, known as the Chandrasekhar limit. HD265435 fits in the second scenario, in which the total mass of a close stellar system of multiple stars is near or above this limit. Only a handful of other star systems have been discovered that will reach this threshold and result in a Type Ia supernova.

Lead author Ingrid Pelisoli from the University of Warwick Department of Physics explains: "We don't know exactly how these supernovae explode, but we know it has to happen because we see it happening elsewhere in the universe."

"One way is if the white dwarf accretes enough mass from the hot subdwarf, so as the two of them are orbiting each other and getting closer, matter will start to escape the hot subdwarf and fall onto the white dwarf. Another way is that because they are losing energy to gravitational wave emissions, they will get closer until they merge. Once the white dwarf gains enough mass from either method, it will go supernova," she says.

Using data from NASA's Transiting Exoplanet Survey Satellite, the team was able to observe the hot subdwarf. While they did not detect the white dwarf, the researchers observed the brightness of the hot subdwarf varied over time; this suggests a nearby massive object was distorting the star into a teardrop shape.

The astronomers then used Palomar Observatory and Keck Observatory's Echellette Spectrograph and Imager (ESI) to measure the radial velocity and rotational velocity of the hot subdwarf star, which allowed them to confirm that the hidden white dwarf is as heavy as our Sun, but just slightly smaller than the Earth's radius. Combined with the mass of the hot subdwarf, which is a little over 0.6 times the mass of our Sun, both stars have the mass needed to cause a Type Ia supernova.

"Keck's ESI data was crucial in determining that the compact binary system exceeds the Chandrasekhar mass limit, which makes HD265435 one of the very few supernova Ia progenitor systems known," says co-author Thomas Kupfer, assistant professor at Texas Tech University's Department of Physics and Astronomy.

As the two stars are already close enough to begin spiraling closer together, the white dwarf will inevitably go supernova in around 70 million years. Theoretical models produced specifically for this study also predict that the hot subdwarf will contract to become a white dwarf star before merging with its companion.

Type Ia supernovae are important for cosmology as 'standard candles.' Their brightness is constant and of a specific type of light, which means astronomers can compare what luminosity they should be with what we observe on Earth, and from that work out how distant they are with a good degree of accuracy. By observing supernovae in distant galaxies, astronomers combine what they know of how fast this galaxy is moving with our distance from the supernova and calculate the expansion of the universe.

"The more we understand how supernovae work, the better we can calibrate our standard candles. This is very important at the moment because there's a discrepancy between what we get from this kind of standard candle, and what we get through other methods," says Pelisoli.

She adds, "The more we understand about how supernovae form, the better we can understand whether this discrepancy we are seeing is because of new physics that we're unaware of and not taking into account, or simply because we're underestimating the uncertainties in those distances."

"There is another discrepancy between the estimated and observed galactic supernovae rate, and the number of progenitors we see. We can estimate how many supernovae are going to be in our galaxy through observing many galaxies, or through what we know from stellar evolution, and this number is consistent. But if we look for objects that can become supernovae, we don't have enough. This discovery was very useful to put an estimate of what a hot subdwarf and white dwarf binaries can contribute. It still doesn't seem to be a lot, none of the channels we observed seems to be enough," Pelisoli says.

Children with a devastating genetic disorder characterized by severe motor disability and developmental delay have experienced sometimes dramatic improvements in a gene therapy trial launched at UCSF Benioff Children's Hospitals.

The trial includes seven children aged 4 to 9 born with deficiency of AADC, an enzyme involved in the synthesis of neurotransmitters, particularly dopamine, that leaves them unable to speak, feed themselves or hold up their head. Six of the children were treated at UCSF and one at Ohio State Wexner Medical Center.

Children in the study experienced improved motor function, better mood, and longer sleep, and were able to interact more fully with their parents and siblings. Oculogyric crisis, a hallmark of the disorder involving involuntary upward fixed gaze that may last for hours and may be accompanied by seizure-like episodes, ceased in all but one patient. Results appear July 12, 2021, in Nature Communications.

Just 135 children worldwide are known to be missing the AADC enzyme, with the condition affecting more people of Asian descent.

The trial borrowed from gene delivery techniques used to treat Parkinson's disease, pioneered by senior author Krystof Bankiewicz, MD, PhD, of the UCSF Department of Neurological Surgery and the Weil Institute for Neurosciences, and of the Department of Neurological Surgery at Ohio State University. Both conditions are associated with deficiencies of AADC, which converts levodopa into dopamine, a neurotransmitter involved in movement, mood, learning and concentration.

Viral Vector, Real-Time MR Imaging Key to Success

In treating both conditions, Bankiewicz developed a viral vector containing the AADC gene. The vector is infused into the brain via a small hole in the skull, using real-time MR imaging to enable the neurosurgeon to map the target region and plan canula insertion and infusion.

"Children with primary AADC deficiency lack a functional copy of the gene, but we had presumed that their actual neuronal pathway was intact," said co-first author Nalin Gupta, MD, PhD, of the UCSF Department of Neurological Surgery and the surgical principal investigator. "This is unlike Parkinson's disease, where the neurons that produce dopamine undergo degeneration."

While the Parkinson's trial focused on the putamen, a part of the brain that plays a key role in this degeneration, Gupta said the AADC gene therapy trial targeted neurons in the substantia nigra and ventral tegmental area of the brainstem, sites that may have more therapeutic benefits.

"The approach for treating AADC deficiency is much more straightforward than it is for Parkinson's," said Bankiewicz. "In AADC deficiency, the wiring of the brain is normal, it's just the neurons don't know how to produce dopamine because they lack AADC."

Physicians who follow patients with AADC deficiency agree that it is usually treated with limited success by managing symptoms, such as with medications used for Parkinson's disease to increase dopamine, melatonin for sleep disturbances and benzodiazepines to relieve oculogyric crisis.

Following gene delivery, PET imaging demonstrated increased brain AADC activity and screening of neurotransmitter metabolites from cerebrospinal fluid showed elevated concentrations, the researchers noted.

At the start of the study, only two of the seven children had partial head control, just one could reach or grasp and none were able to sit independently. Six of the seven were described as irritable and all but one had insomnia. Their baseline motor skill scores were all within the severe impairment range. Symptoms eased after surgery, starting with oculogyric crisis.

"Remarkably, these episodes were the first to disappear and they never returned," said Bankiewicz. "In the months that followed, many patients experienced life-changing improvements. Not only did they begin laughing and have improved mood, but some were able to start speaking and even walking."

New Goals Reached in Sitting, Walking, Feeding, Speech

All patients experienced recognizable gains in motor function, manifested by increased tone and better head and trunk control, and purposeful limb movements. Head control was attained by six of the seven children by month 12 and four were able to sit independently by this time. Also, at 12 months, three patients could reach and grasp and two were able to walk with trunk support. Two-and-a-half years after surgery, one patient started to take independent steps. One patient was able to speak using a vocabulary of about 50 single words by 12 months and a second was able to communicate with an assistive device between 12 to 18 months after gene delivery.

Significant improvements were reported by parents and caregivers in sleep and mood, as well as in feeding difficulties, such as vomiting, and upper airway obstruction due to profuse mucus secretions and congestion. The procedure was well tolerated without adverse short-term or long-term effects, but one child died at seven months after surgery. The patient appeared to be in good health and the cause of death is "most likely attributable to the underlying primary disease," the researchers stated.

The study follows the Parkinson's trial, which also showed positive results with increased durations of well-controlled symptoms. The Bankiewicz team will start two new gene therapy trials, using the same surgical techniques and viral vector, for early Alzheimer's disease and for multiple system atrophy, a rare neurodegenerative disorder. Both trials will run at Ohio State University and will start next month.

Sugarcane is one of the most productive plants on Earth, providing 80 percent of the sugar and 30 percent of the bioethanol produced worldwide. Its size and efficient use of water and light give it tremendous potential for the production of renewable value-added bioproducts and biofuels.

But the highly complex sugarcane genome poses challenges for conventional breeding, requiring more than a decade of trials for the development of an improved cultivar.

Two recently published innovations by University of Florida researchers at the Department of Energy’s Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) demonstrated the first successful precision breeding of sugarcane by using CRISPR/Cas9 genome editing — a far more targeted and efficient way to develop new varieties.

CRISPR/Cas9 allows scientists to introduce precision changes in almost any gene and, depending on the selected approach, to turn the gene off or replace it with a superior version. The latter is technically more challenging and has rarely been reported for crops so far.

In the first report, researchers demonstrated the ability to turn off variable numbers of copies of the magnesium chelatase gene, a key enzyme for chlorophyll biosynthesis in sugarcane, producing rapidly identifiable plants with light green to yellow leaves. Light green plants did not show growth reduction and may require less nitrogen fertilizer to produce the same amount of biomass. That study, published in Frontiers in Genome Editing, was led by CABBI researchers Fredy Altpeter, Professor of Agronomy at the University of Florida’s Institute of Food and Agricultural Sciences (IFAS), and Ayman Eid, a Postdoctoral Research Associate in Altpeter’s lab.

The second study, also published in Frontiers in Genome Editing, achieved efficient and reproducible gene targeting in sugarcane, demonstrating the precise substitution of multiple copies of the target gene with a superior version, conferring herbicide resistance. Scientists co-introduced a repair template together with the gene-editing tool to direct the plant’s own DNA repair process so that one or two of the thousands of building blocks of the gene, called nucleotides, were precisely replaced in the targeted location. The result was that the gene product was still fully functional and could no longer be inhibited by the herbicide. That study was led by Altpeter and former CABBI Postdoc Mehmet Tufan Oz.

Altpeter’s lab, part of CABBI’s groundbreaking project to develop new oil-rich sugarcane varieties, has pioneered research with sugarcane genome editing using the TALEN gene-editing system. But the two recent publications are the first to successfully demonstrate CRISPR gene-editing in sugarcane as well as gene targeting for precision nucleotide substitution in sugarcane using any genome-editing tool.

“Now we have very effective tools to modify sugarcane into a crop with higher productivity or improved sustainability,” Altpeter said. “It’s important since sugarcane is the ideal crop to fuel the emerging bioeconomy.”

Sugarcane is a hybrid of two kinds of parent plants, so it has multiple sets of chromosomes rather than just two, as with humans or “diploid” plants. That creates genetic redundancy — with many sets of genes doing the same job — which may contribute to the plant’s productivity: If one set breaks, there’s a backup. But it makes sugarcane extremely difficult to modify. Crop scientists have to target all the genes and copies that govern a particular trait in order to make improvements.

With conventional breeding, two types of sugarcane are cross-bred to reshuffle the genetic information present in each parent in the hope of enhancing a desirable trait such as disease resistance. The problem is that genes are transferred from the parents to offspring in blocks, and desirable traits are often linked with deleterious genetic material. This means scientists often have to do multiple rounds of backcrossing and screen thousands of plants to restore the elite background, or underlying plant characteristics, in addition to improving one trait they’re attempting to modify. The process is more time-consuming and costly in plants with complex genomes like sugarcane.

Precise gene-editing technologies such as CRISPR-Cas9 offer a much more targeted path to crop improvement because it avoids the reshuffling of genetic information and simply changes inferior gene versions into superior ones. Given the sugarcane genome’s complexity, Altpeter and his team focused initially on genes that control noticeable traits — leaf color and herbicide resistance — so they could determine if the edits worked.

Beyond providing an easily identifiable phenotype, the targeted genes may prove useful in future research. Changing the chlorophyll content of sugarcane has the potential to increase canopy level photosynthesis or reduce the requirement for nitrogen fertilizer, based on previous plant modeling. Sugarcane is a tall, dense plant, with the top leaves getting lots of sun and shading lower foliage. If the upper leaves have less chlorophyll, sunlight can penetrate deeper into the plant, increasing its biomass with the same amount of light and less fertilizer. Herbicide resistance is not only an agronomically desirable trait to facilitate weed management; it will also facilitate future gene-editing efforts by enabling suppression of non-edited plant cells.

At CABBI, Altpeter and his team are already applying the results to develop improved sugarcane lines. Sugarcane has many different gene targets that can translate into more biomass or the production of lipids or specialty fatty acids — all of which would advance CABBI’s goals to produce fuels and other products from plants to replace petroleum. Because the crop is already harvested and processed for sugar extraction, the basic infrastructure to process its raw material into a product on a shelf is essentially in place.

“Adding value streams is relatively inexpensive compared to other crop alternatives,” Altpeter said.

Butterflies and moths have beautiful wings: the bright flare of an orange monarch, the vivid stripes of a swallowtail, the luminous green of a Luna moth. But some butterflies flutter on even more dramatic wings: parts of their wing, or sometimes the entire wing itself, are actually transparent.

Many aquatic organisms, including jellies and fish, are transparent. But transparent butterfly and moth wings are so arresting that merely catching a glimpse of one typically causes a human to lunge for a camera or at least point it out to their friends. These enigmatic, transparent butterfly wings have not been studied comprehensively.

Doris Gomez and Marianne Elias (French National Center for Scientific Research) set out to change that. Last week, along with a multidisciplinary team of ecologists, biologists and physicists, they published a massive survey on the optics and ecological implications of moths and butterflies with transparent wings in the Ecological Society of America's journal Ecological Monographs. They discovered that transparency has evolved in Lepidoptera more than once, and that there are many ways to be transparent.

Gomez, an ecologist who has studied the physics and ecological aspects of iridescence in hummingbird wings and other bird coloration, was intrigued by these so-called "glasswing" butterflies and moths when she met Elias, an evolutionary biologist who worked on the ecology and evolution of the tropical butterflies Ithomiini, which have transparent wings. Gomez was startled to find that almost nothing had been written about transparency in Lepidoptera, nor in any other terrestrial animal.

"This paper is a breakthrough because everything that's been known so far on transparency was about aquatic organisms," Gomez said. "Transparency is so rare in terrestrial organisms that people never bothered to study it comprehensively."

She and her team analyzed 123 species of Lepidoptera from samples in the French Museum of Natural History's collection. They found transparency, or "clearwing" species, in 31 out of 124 families. But not all species accomplish transparency in the same way. They examined the extent to which transparency affects thermoregulation and provides protection against ultraviolet radiation.

Many insects, including wasps, flies and dragonflies, have clear wings. Their wings consist of a transparent membrane made of chitin. Butterfly and moth wings are made of the same kind of transparent membrane, but in most cases moths and butterflies have opaque scales obscuring the membrane. The scales are what are responsible for their mesmerizing patterns and coloration.

Gomez and her team discovered that clearwing species have a number of ways to make their wings transparent. Some transparent moths and butterflies have no scales on their wings at all, leaving the chitin membrane to show through. Many other species do have scales, which can be transparent, upright, narrow or hair-like, allowing light through the wing.

Physicists have studied instances of transparency in individual species or genera, in the hopes of understanding the physics of how to adapt biological concepts to make people, vehicles and even structures invisible or transparent. But before now, no one had appreciated the wealth of approaches lepidopterans can take to achieve transparency, or the fact that it has evolved multiple times in different groups.

"This is the first comparative analysis of transparent butterfly wings," said Elias. "What is notable is that transparency has evolved several times independently. But the way the wings become transparent can be dramatically different, from highly packed transparent scales to the mere absence of scales, through scale reduction in size and density. There are many ways of being transparent. We don't know why this diversity exists."

In some cases, different strategies lead to the same level of transparency, leaving researchers pondering why such diversity exists at all. They theorize that transparency may be beneficial in different ways for different species, including as camouflage or to mimic wasp and bees. Transparency also seems to help moths and butterflies regulate their body temperature, but does not protect them from UV radiation.

Gomez, who has a passion for working with scientists from across other disciplines, included physicists in the study to explore the optical properties of the wings including discerning what birds, their would-be predators, see when they look at a transparent butterfly. They found that the more light that can pass through a wing - i.e., the more transparent it is - the less visible the butterfly is to predators. Transparency acts like the ultimate camouflage.

Like the butterflies themselves, the results are compelling. However, the scientists emphasize that the study has raised more questions and avenues of exploration to continue to uncover the evolutionary role and ecological implications of transparency.

"Butterflies are such iconic organisms," said Gomez. "They're so wonderful to study. I like to study complex concepts, like iridescence and transparency because there is so much to explore - and it's so easy to get everyone excited about them."

Chronic alcohol abuse and hepatitis can injure the liver and lead to fibrosis, the buildup of collagen and scar tissue. As a potential approach to treating liver fibrosis, University of California San Diego School of Medicine researchers and their collaborators are looking for ways to stop liver cells from producing collagen.

"So we thought...what if we take immunotoxins and try to get them to kill collagen-producing cells in the liver," said team lead Tatiana Kisseleva, MD, PhD, associate professor of surgery at UC San Diego School of Medicine. "If these antibodies carrying toxic molecules can find and bind the cells, the cells will eat up the 'gift' and die."

In a study published July 12, 2021 in Proceedings of the National Academy of Sciences, Kisseleva and collaborators provide the first evidence that liver fibrosis might be treatable with immunotoxins designed to bind a protein called mesothelin. Mesothelin is rarely found in the healthy human body. Only cancer cells and collagen-producing liver cells, known as portal fibroblasts, make the protein.

Kisseleva teamed up with co-author Ira Pastan, MD, at the National Cancer Institute, part of the National Institutes of Health (NIH). Pastan is co-discoverer of mesothelin and an expert on using immunotoxins to target the protein on cancer cells. He leads several clinical trials testing the approach to treat patients with ovarian cancer, mesothelioma and pancreatic cancer.

To test Pastan's immunotoxins in the context of liver fibrosis, Kisseleva's team first needed a model. Since the immunotoxins specifically recognize human mesothelin, a traditional mouse model of liver fibrosis wouldn't work. Instead, they transplanted human liver cells isolated from patients to mice and treated them with the anti-mesothelin immunotoxin.

Compared to untreated mice, 60 to 100 percent of human mesothelin-producing cells were killed by the immunotoxins, which also reduced collagen deposition.

Treatment for liver fibrosis is currently very limited. According to the NIH, weight loss is currently the only known method for reducing liver fibrosis associated with non-alcoholic fatty liver disease. Alcoholic liver disease is most commonly treated with corticosteroids, but they are not highly effective. Early liver transplantation is the only proven cure, but it is offered only at select medical centers to a limited number of patients.

"What we want to know now is, can this same strategy be applied to other organs?" Kisseleva said. "Surprisingly enough, the same cells are responsible for fibrosis in the lung and kidneys. This is especially exciting because we already know from Dr. Pasten's cancer clinical trials that anti-mesothelin immunotoxins are safe in humans, potentially speeding up their application in other areas."

Having a home near a busy airport certainly has its perks. It is close to many establishments and alleviates the problem of wading through endless traffic to catch flights. But it does come at a cost -- tolerating the jarring sounds of commercial airplanes during landing and takeoff.

Researchers at Texas A&M University have conducted a computational study that validates using a shape-memory alloy to reduce the unpleasant plane noise produced during landing. They noted that these materials could be inserted as passive, seamless fillers within airplane wings that automatically deploy themselves into the perfect position during descent.

"When landing, aircraft engines are throttled way back, and so they are very quiet. Any other source of noise, like that from the wings, becomes quite noticeable to the people on the ground," said Dr. Darren Hartl, assistant professor in the Department of Aerospace Engineering. "We want to create structures that will not change anything about the flight characteristics of the plane and yet dramatically reduce the noise problem."

The researchers have described their findings in the Journal of Aircraft.

Aircraft noise has been an ongoing public health issue. Airplanes can generate up to 75-80 decibels during landing, which can be damaging to hearing over the long term. For example, studies have shown that people exposed to sustained aircraft noise can experience disturbed sleep and an increased risk of stroke and heart disease compared to those who do not live near airports.

The source of aircraft noise is different during ascent and descent. During takeoff, the engines are the primary source of noise. On the other hand, when airplanes slow down to land, the engines do not need to generate power and are mostly idling. At this time, the wings begin to reconfigure themselves to slow down the airplane and prepare for touchdown. Similar to the opening of Venetian blinds, the front edge of the wing separates from the main body. This change causes air to rush into the space created, circle around quite violently and produce noise.

"The idea is similar to how a sound is generated in a flute," said Hartl. "When a flute is played, air blown over a hole begins to swirl around the hole, and the size, the length and how I cover the holes, produces a resonant sound of a certain frequency. Similarly, the circulating air in the cove created between the front edge of the wing and the main wing resonates and creates a sharp, unpleasant noise."

Earlier work from Hartl's collaborators at NASA showed that fillers used as a membrane in the shape of an elongated "S" within this cove could circumvent the noise-causing air circulation and thereby lessen the jarring sound. However, a systematic analysis of candidate materials that can assume the desired S-shaped geometry during descent and then recess back into the front edge of the wing after landing was lacking.

To address this gap, the researchers performed comprehensive simulations to investigate if a membrane made of a shape-memory alloy could go back and forth, changing shape for every landing. Their analysis considered the geometry, the elastic properties of the shape-memory alloy and the aerodynamic flow of air around the material during descent. As a comparison, the researchers also modeled the motion of a membrane made of a carbon-fiber-reinforced polymer composite under the same airflow conditions.

Hartl said these types of simulations are computationally expensive since the flow of air around the conformal material has to be modeled while analyzing the air-induced motion of the material.

"Every time the air applies some pressure to the material, the material moves. And every time the material moves, the air moves differently around it," he said. "So, the behavior of the airflow changes the structure, and the motion of the structural changes the airflow."

Consequently, the team had to perform calculations hundreds to thousands of times before the motion of the materials was correctly simulated. When they analyzed the outcomes of their simulations, they found that both the shape-memory alloy and the composite could change their shape to reduce air circulation and thereby reduce noise. However, the researchers also found that the composite had a very narrow window of designs that would enable noise canceling.

As a next step, Hartl and his team plan to validate the results of their simulations with experiments. In these tests, the researchers will place scaled-down models of aircraft wings with the shape-memory alloy fillers into wind tunnels. The goal is to check if the fillers can deploy into the correct shape and reduce noise in near real-world situations.

"We would also like to do better," said Hartl. "We might be able to create smaller structures that can reduce noise and do not require the S-shape, which are actually quite large and potentially heavy."

[Points]

319 Tb/s long-haul transmission of wideband (>120 nm) S, C and L-bands signal using 552 PDM-16QAM, wavelength-division multiplexed channels in a 4-core optical fiber

Long-distance transmission over 3,001 km enabled by adoption of both erbium and thulium doped-fiber amplifiers and distributed Raman amplification

Demonstration shows potential of SDM fibers with standard-cladding diameter and compatibility with existing cabling technologies for near-term adoption of high-throughput SDM fiber systems

[Abstract]

Researchers from the National Institute of Information and Communications Technology (NICT, President: TOKUDA Hideyuki, Ph.D.), Network Research Institute, succeeded the first S, C and L-bands transmission over long-haul distances in a 4-core optical fiber with standard outer diameter (0.125 mm). The researchers, lead by Benjamin J. Puttnam, constructed a transmission system that makes full use of wavelength division multiplexing technology by combining different amplifier technologies, to achieve a transmission demonstration with date-rate of 319 terabits per second, over a distance of 3,001 km. Using a common comparison metric of optical fiber transmission the data-rate and distance produce of 957 petabits per second x km, is a world record for optical fibers with standard outer diameter.

In this demonstration, in addition to the C and L-bands, typically used for high-data-rate, long-haul transmission, we utilize the transmission bandwidth of the S-band, which has not yet been used for further than single span transmission. The combined >120nm transmission bandwidth allowed 552 wavelength-division multiplexed channels by adopting 2 kinds of doped-fiber amplifier together with distributed Raman amplification, to enable recirculating transmission of the wideband signal. The standard cladding diameter, 4-core optical fiber can be cabled with existing equipment, and it is hoped that such fibers can enable practical high data-rate transmission in the near-term, contributing to the realization of the backbone communications system, necessary for the spread of new communication services Beyond 5G.

The results of this experiment were accepted as a post-deadline paper presentation at the International Conference on Optical Fiber Communications (OFC 2021).

[Background]

Over the past decade, intensive research has been carried out worldwide to increase the data rates in optical transmission systems using space-division multiplexing as a means to meet the exponentially increasing demand for optical data transmission. More recently, interest in fibers with the same 125 μm cladding diameter as standard single-mode fibers has grown due to their compatibility with conventional cabling infrastructure and concerns over the mechanical reliability of larger fibers. Particularly with multi-core fibers (MCFs), reducing the cladding diameter limits the number of spatial channels, leading to increasing interest in combining such fibers with wider transmission bandwidths in order to meet the expected growth in transmission capacity expected in SDM fibers. Until now, NICT has built various transmission systems that make use of wavelength division multiplexing across the C and L-bands together with state-of-the-art modulation technology to explore high data-rate transmission in a range of new optical fibers. Recently, NICT and research groups around the world have begun to explore S-band transmission, leading to several new records for transmission capacity in optical fibers, but transmission distance has been limited to only a few tens of kilometers.

[Achievements]

NICT has built a long-distance transmission system around a 4-core optical fiber with a standard cladding diameter to exploit wider transmission bandwidth of >120nm across S, C and L-bands. The system exploits wavelength division multiplexing (WDM) and a combination of optical amplification technology to enable long-haul transmission of 552 WDM channels from 1487.8 nm to 1608.33 nm. The system was used to measure achievable transmission throughput with each channel modulated with PDM-16QAM modulation at distances up to 3,001 km, where a data-rate of 319 terabits per second was achieved. This result may be compared to achievements in other SDM fibers and transmission regimes by calculating the product of transmission capacity and distance, often used as a comparison metric. The data-rate x distance product becomes 957 petabits per second x km, which is over 2.7 times larger than previous demonstrations in SDM fibers with standard outer diameter.

Long distance transmission, not previously demonstrated with S-band signals, was enabled by constructing a recirculating transmission loop experimental set-up that combined 2 kinds of rare-earth doped fiber amplifiers with Raman amplification distributed along the transmission fiber itself.

The 4-core MCF with standard cladding diameter is attractive for early adoption of SDM fibers in high-throughput, long-distance links, since it is compatible with conventional cable infrastructure and expected to have mechanical reliability comparable to single-mode fibers. Beyond 5G, an explosive increase from new data services is expected and it is therefore crucial to demonstrate how new fibers can meet this demand. Hence, it is hoped that this result will help the realization of new communication systems that can support new bandwidth hungry services.

[Future Prospects]

NICT will continue to develop wide-band, long-distance transmission systems and explore how to further increase transmission capacity of low-core-count multi-core fibers and other novel SDM fibers. Further, we will work to extend the transmission range to trans-oceanic distances.

The paper containing the results of this experiment was published at the International Conference on Optical Fiber Communication ((OFC2021, June 6 (Sun) to June 11 (Fri)), one of the largest international conferences related to optical fiber communication, this year held virtually due to Corona virus travel restrictions. It was highly evaluated and was presented in the Post Deadline session, known for release of latest important research achievements on June 11 (Fri) 2021 local time.

A research team from the University of Göttingen and the University of British Columbia (Canada) has investigated how people in five different countries react to various usages of genome editing in agriculture. The researchers looked at which uses are accepted and how the risks and benefits of the new breeding technologies are rated by people. The results show only minor differences between the countries studied - Germany, Italy, Canada, Austria and the USA. In all countries, making changes to the genome is more likely to be deemed acceptable when used in crops rather than in livestock. The study was published in Agriculture and Human Values.

Relatively new breeding technologies, such as CRISPR gene editing, have enabled a range of new opportunities for plant and animal breeding. In the EU, the technology falls under genetic engineering legislation and is therefore subject to rigorous restrictions. However, the use of gene technologies remains controversial. Between June and November 2019, the research team collected views on this topic via online surveys from around 3,700 people from five countries. Five different applications of gene editing were evaluated: three relate to disease resistance in people, plants, or animals; and two relate to achieving either better quality of produce or a larger quantity of product from cattle.

"We were able to observe that the purpose of the gene modification plays a major role in how it is rated," says first author Dr Gesa Busch from the University of Göttingen. "If the technology is used to make animals resistant to disease, approval is greater than if the technology is used to increase the output from animals." Overall, however, the respondents reacted very differently to the uses of the new breeding methods. Four different groups can be identified: strong supporters, supporters, neutrals, and opponents of the technology. The opponents (24 per cent) identify high risks and calls for a ban of the technology, regardless of possible benefits. The strong supporters (21 per cent) see few risks and many advantages. The supporters (26 per cent) see many advantages but also risks. Whereas those who were neutral (29 per cent) show no strong opinion on the subject.

A single tree along a city street or in a backyard can provide measurable cooling benefits, according to a new study from American University. The research shows that "distributed" trees, those that are stand-alone and scattered throughout urban neighborhoods, can help to reduce evening heat. The research suggests that planting individual trees can be a strategy to mitigate urban heat, particularly in areas where land for parks can be scarce.

"There are plenty of good reasons to plant trees, but our study shows we shouldn't underestimate the role that individual trees can play in mitigating heat in urban areas," said Michael Alonzo, assistant professor of environmental science and lead author of the new study. "City planners can take advantage of the small spaces that abound in urban areas to plant individual trees." The study is published in Environmental Research Letters.

While urban parks provide important mid-day cooling for residents and visitors, the key to cooling from individual trees happens in the evening. In the new study, which was conducted in Washington, D.C., cooling benefits from distributed trees were found to occur around 6 or 7 p.m. and after sunset. The study revealed lower temperatures in neighborhoods where at least half the area was covered by canopy from distributed trees. Temperatures were 1.4 degrees Celsius cooler in the evening compared with areas with few trees. Even in the predawn hour, areas with only modest distributed canopy cover (about 20 percent of the area) were cooler than those with no trees, showing that on average, afternoon and evening cooling effects last well into the night, Alonzo added.

To arrive at the findings, Alonzo and his colleagues examined air temperature readings. The data was collected over one hot summer day in 2018, across different areas in Washington, D.C. and at multiple times throughout the day, resulting in more than 70,000 air temperature readings. In their analysis, Alonzo and his colleagues examined tree canopy over paved surfaces, over unpaved surfaces, and both patches such as parks, and distributed trees, such as those one might plant in their back or front yards.

The new study confirms that planting individual trees should be considered as part of a strategy to combat rising temperatures in urban areas. In hot summer months many cities across the United States turn into "heat islands." Due to the urban heat island effect, urban areas, with fewer green spaces and higher amounts of impervious surface, get hotter compared to their rural surroundings.

In urban areas, people are more likely to live adjacent to distributed trees rather than parks. In D.C., there are many places to plant individual trees where canopy will shade paved or unpaved surfaces: on streets with single family homes, streets with rowhouses, backyard or small park plantings, Alonzo said. This opens up avenues for increasing the racial and socioeconomic equity of tree planting, but more effort is required to first reduce impervious surface cover in the most built-up residential and commercial districts, Alonzo added. The top five trees along D.C.'s streets include several species of maples, oaks and elms, all of which provide plentiful shade.

Climate studies show that urban temperatures are warming at all times of day including evenings. Yet studying the cooling benefits from individual trees, as well as their benefits during evening hours, has not been widely researched, Alonzo said, and this is an area scientists should continue to explore. More research will be needed in other locations in the United States and under different weather conditions. Alonzo also plans to conduct more research and has collected air temperature readings by bicycle around D.C. during the pandemic.

Though the study was conducted in D.C., Alonzo said the findings are likely applicable along the East Coast or in other cities with a similar climate.

"Evenings are not quite the respite from heat that we once had," Alonzo said. "These distributed trees do help the city cool off in the evening and that's important for human health."

LOWELL, Mass. - Researchers led by a UMass Lowell environmental science professor say mercury measurements in a Massachusetts forest indicate the toxic element is deposited in forests across the globe in much greater quantities than previously understood.

The team's results underscore concern for the health and well-being of people, wildlife and waterways, according to Prof. Daniel Obrist, as mercury accumulating in forests ultimately runs off into streams and rivers, ending up in lakes and oceans.

Mercury is a highly toxic pollutant that threatens fish, birds, mammals and humans. Hundreds of tons of it are released into the atmosphere each year by coal-burning power plants, as well as through gold mining and other industrial processes, and the pollutant is distributed by winds and currents across the globe. Long-term exposure to mercury, or consuming food containing high levels of the pollutant, can lead to reproductive, immune, neurological and cardiovascular problems, according to Obrist, chair of UMass Lowell's Department of Environmental, Earth and Atmospheric Sciences.

Forests constitute the world's most abundant, productive and widespread ecosystems on land, according to Obrist, who said the study is the first that examines a full picture of how mercury in the atmosphere is deposited at any rural forest in the world, including the deposition of mercury in its gaseous form, which most previous studies do not address.

"Trees take up gaseous mercury from the atmosphere through their leaves and as plants shed their leaves or die off, they basically transfer that atmospheric mercury to the ecosystems," he said.

The results of the project, which is supported by a three-year, $873,000 grant from the National Science Foundation (NSF), were published today in an issue of the Proceedings of the National Academy of Sciences. UMass Lowell student Eric Roy, a double-major in meteorology and mathematics from Lowell, is among the study's co-authors.

For the past 16 months, the team has measured how mercury in the atmosphere gets deposited at Harvard Forest in Petersham, a nearly 4,000-acre site that includes hardwood deciduous broadleaf trees such as red oak and red maple that shed their leaves every year. A set of measurement systems placed at various heights on the forest's 100-foot-tall research tower assessed the site's gaseous mercury deposition from the tree canopy to the forest floor.

"Seventy-six percent of the mercury deposition at this forest comes from gaseous atmospheric mercury. It's five times greater than mercury deposited by rain and snow and three times greater than mercury that gets deposited through litterfall, which is mercury transferred by leaves falling to the ground and which has previously been used by other researchers as a proxy for estimating gaseous mercury deposition in forests," Obrist said.

"Our study suggests that mercury loading in forests has been underestimated by a factor of about two and that forests worldwide may be a much larger global absorber and collector of gaseous mercury than currently assumed. This larger-than-anticipated accumulation may explain surprisingly high mercury levels observed in soils across rural forests," he said.

Plants seem to dominate as a source of mercury on land, accounting for 54 to 94 percent of the deposits in soils across North America. The total global amount of mercury deposited to land currently is estimated at about 1,500 to 1,800 metric tons per year, but it may be more than double if other forests show similar levels of deposition, according to Obrist.

The researchers are continuing their work at a second forest in Howland in northern Maine. Howland Forest, a nearly 600-acre research site full of evergreens that retain their leaves year-round, offers a distinctly different habitat than the deciduous forest in Petersham. Assessing both forests will allow researchers to examine differences in mercury accumulation between different forest types, Obrist said.

The work is providing a hands-on research experience for Roy, a UMass Lowell Honors College student who was invited to become a member of the university's Immersive Scholar program in 2019. The initiative enables first-year students with outstanding academic credentials to participate in lab work and research right from the start of their academic studies.

"It's really exciting to be a co-author," Roy said. "This study allowed us to quantify how much mercury is being accumulated in this type of forest. Modelers can use these results to improve their understanding of how mercury cycles through the environment on a global scale and how that might change in the future."

Roy helped analyze the data collected in the field.

"Eric's contributions to the study are tremendous. It's not very common for an undergrad to play such an important role in a major, federally funded research project," Obrist said. "His work is really impressive and he has become more and more active in data analysis and doing complex flux calculations and data processing. He really earned himself second author position in the paper in the Proceedings of the National Academy of Sciences."