Earth

The thylacine, that famous extinct Australian icon colloquially known as the Tasmanian Tiger, is revealed to have been only about half as big as once thought - not a "big" bad wolf after all.

Using advances in 3D analysis, a recent study by Monash University's Biomedicine Discovery Institute and School of Biological Sciences, shows the thylacine, an icon of Australian biodiversity and extinction, only weighed about 17 kilograms on average. This positions it as just over half the size of the previously most commonly used estimate of 29.5 kilograms, substantially revising how we understand its biology and role in Australian ecosystems.

The research, published in Proceedings of the Royal Society B, is led by PhD student Douglass Rovinsky under the supervision of the BDI's Dr Justin W Adams and Assoc Prof Alistair Evans from the School of Biological Sciences.

It unravels the mystery of the size of the thylacine by bringing together traditional measurement techniques with advanced three-dimensional (3D) scanning and volumetric methods, and the largest database of museum specimens that spans 6 countries and incorporates 93 individual thylacines.

The researchers established that there were strong differences in the average male and female body size, with the male mean of 19.7 kilograms and female mean of 13.7 kilograms. The mixed sex population mean of 16.7 kilograms is then well below the 21 kg threshold for when predators are likely to take large prey.

"We demonstrate strong differences in average male and female body size. This result also fundamentally challenges prior views about the thylacines as a carnivore, and underscores that thylacines were a predator that evolved to consume prey smaller than themselves," said Dr Adams.

Despite extinction in the 1930s and film footage, the species is a true enigma with almost no direct observations supporting an understanding of their behaviour and biology.

"We wish we could watch just how the thylacine hunted, and what sort of prey it could take - this is our closest look yet at an essential ingredient of the predator's behaviour, how big it really was," said Assoc Prof Evans.

The newly established body mass estimates for thylacines place them as specialists on small prey, challenging prior interpretations of them as convergent with species like wolves that specialise in pack-hunting prey substantially larger than themselves.

"Rewriting the thylacine as a smaller animal changes the way we look at its position in the Australian ecosystem - because what a predator can (and needs to) eat is very much dependent on just how big they are," said Mr Rovinsky. "Many of the 19th century newspaper reports just might have been 'tall tales' - told to make the thylacine seem bigger, more impressive... and more dangerous!"

Every year, 150 to 300 children in the United States are diagnosed with diffuse intrinsic pontine gliomas (DIPGs), aggressive and lethal tumors that grow deep inside the brain, for which there are no cures. In a study funded by the National Institutes of Health, researchers showed that experimental drugs designed to lower the body's natural production of alpha-ketoglutarate extended the lives of mice harboring DIPG tumors by slowing the growth of the cancer cells. Interestingly, they also found that artificially raising alpha-ketoglutarate levels with DIPG-causing genes may slow the growth of other brain tumors. The results, published in Cancer Cell, were part of a nationwide study that explored the cyclical role that cancer cell metabolism may play in regulating brain tumor genes.

Led by senior author Sriram Venneti, M.D., Ph.D., and a team of researchers at the University of Michigan Medical School in Ann Arbor, the researchers primarily studied H3K27M tumors, DIPGs linked to mutations in a gene, called histone 3. Histones are proteins cells spool chromosomes around. This helps cells cram lengthy chromosomes into tiny nuclei and control gene activity. Any genes that are buried in the spools cannot be read and are thus turned off. Cells can "epigenetically" fine tune spooling by using a process known as methylation to chemically tag histones. For years scientists knew that cancer genes often alter the metabolism of tumors. In this study, the researchers not only found that this may be true for patients with H3K27M tumors but also that these alterations in metabolism may be part of a feedback loop involving alpha-ketoglutarate (α-KG), that epigenetically keeps these and other brain tumors in a cancerous state.

Brain scans of H3K27M patients showed that they had higher levels of certain precursor metabolites - namely glucose and glutamine - than patients with deep brain tumors who do not carry the H3K27M mutations. Then through a series of detailed experiments on mice and cells in petri dishes, the researchers found that H3K27M mutations induced the cancer cells to produce high levels of α-KG and this, in turn, spurred more growth. Further results suggested that this happened because α-KG prevented methylation of histones and thus epigenetically kept genes that are vital for cancer cells exposed and active. For instance, lowering α-KG levels with experimental drugs increased histone methylation, slowed cancer cell growth, and helped mice harboring the DIPG tumors live longer. In contrast, they saw surprisingly opposite results in lower grade tumors associated with mutations in isocitrate dehydrogenase genes (IDH1), which naturally produce lower levels of α-KG. Introducing H3K237M genes into IDH1 tumors slowed growth by raising alpha-ketoglutarate levels which, in turn, increased methylation and turned off cancer-sustaining genes. The researchers concluded that understanding the intricate details behind these feedback loops may help researchers devise effective ways to treat DIPG and other brain tumors.

Using high-resolution data from the joint NASA-U.S. Geological Survey Landsat program, researchers have created the first map of the causes of change in global mangrove habitats between 2000 and 2016 - a valuable tool to aid conservation efforts for these vital coastline defenders.

Mangroves are hardy trees and shrubs that grow in the salty, wet, muddy soils of Earth's tropical and subtropical coastlines. They protect the coastlines from erosion and storm damage; store carbon within their roots, trunks, and in the soil; and provide habitats for commercially important marine species. The study showed that overall, mangrove habitat loss declined during the period. However, losses from natural causes like erosion and extreme weather declined more slowly than human causes such as farming and aquaculture. For conservation and resource managers trying to prevent loss or re-establish new habitats, this finding highlights the need for strategies that account for natural causes of loss.

The global map will benefit researchers investigating the carbon cycle impacts of mangrove gain and loss, as well as help conservation organizations identify where to protect or restore these vital coastal habitats.

Protecting coastal boundaries

In 2010, mangroves covered about 53,000 square miles of Earth's coastlines, straddling the line between salt water and muddy soil with their long, stilt-like root systems. The majority of these ecosystems are found in Southeast Asia, but they exist throughout the tropical and subtropical latitudes over the globe.

These hardy trees and shrubs provide a "triple whammy" of environmental benefits, said Lola Fatoyinbo Agueh, an environmental scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Mangroves are uniquely efficient carbon sinks: locations where carbon is stored out of the atmosphere. They make up only 3 percent of Earth's forest cover, but if they were all cut down, they could contribute up to 10 percent of global carbon emissions. Adapted to withstand salty water, strong tides, low-oxygen soils and warm tropical temperatures, mangroves protect the coastlines from erosion and storm surges and provide a "nursery" for marine creatures.

"Mangroves provide shoreline protection from extreme storms and tidal waves," said Fatoyinbo. "Because they are amphibious trees, their root structure protects the inland areas from the coast, and they also protect the coast from the inland areas, because they're able to accumulate a lot of the soil that comes in from upstream or from the coast. They hold that sediment in their roots and essentially grow new land. If you have areas where you have increased erosion due to sea level rise, mangroves might counter that."

Mangroves have been threatened by deforestation for decades, as agriculture and aquaculture, urban development and harvesting have caused the loss of more than a quarter of mangrove forests in the past 50 years. Forests in Southeast Asia have been especially hard-hit, as countries like Indonesia clear mangroves to make room for shrimp and rice farming.

When planning conservation or restoration efforts for these crucial forests, experts need to know what the primary human and natural threats are for their area. Using high-resolution imagery from Landsat 5, 7 and 8, Fatoyinbo and her colleagues used machine learning algorithms to create a high-resolution map of mangrove losses between 2000 and 2016, with an important addition: They showed what drove those losses.

The team found that nearly 1300 square miles of mangrove forests were lost during the study period, or about 2 percent of global mangrove area. Sixty-two percent of the lost area was due to human causes, mainly farming and aquaculture. The rest was due to natural causes, including erosion and extreme weather events.

Over the period, both human and natural drivers of loss declined, the team said. But human impact declined more quickly.

"On the one hand, it's great," said lead author Liza Goldberg, a NASA Goddard intern and rising freshman at Stanford University. "It shows that conservation efforts are increasing in effectiveness on a local scale, and there's an increase in awareness of the importance of mangroves, economic damage from storms, and loss of life. But on the flip side, the decline in losses, especially in Southeast Asia, means that in many areas, there are simply no more mangroves to lose."

While natural drivers of loss also decreased, they did so more slowly, the team said. This shift in the proportion of loss drivers poses challenges for conservation and resource managers.

"The main takeaway is that conservation and restoration efforts should continue to increase their focus on evaluating and mitigating natural threats," Goldberg said.

Besides their role in stabilizing coastal ecosystems, mangroves are vital to Earth's carbon cycle - the exchange of carbon between the land, ocean, atmosphere and living things. Their leaves fall to the soil and decompose very slowly, creating carbon-rich peat instead of releasing it back into the atmosphere. When these trees and shrubs are cut down or destroyed by storms or floods, that carbon instead escapes into the atmosphere, where it contributes to climate change as a greenhouse gas.

"The type of carbon emissions you'll see from mangroves depend on what type of conversion is happening," said Fatoyinbo. "If you're doing clear-cutting and digging up the soil where most of the carbon is stored to put in a shrimp pond, that will have a very different rate of emission from, let's say, a tropical storm that comes in and damages standing trees, but where you might have regrowth happening afterwards."

The team is collaborating with nonprofit and other organizations to put their data to work, helping with carbon emissions estimation, conservation planning and other initiatives to protect these ecosystems for future generations.

Growing young scientists

Goldberg began working with Fatoyinbo and David Lagomasino when she was just 14, starting with basic lab tasks and advancing quickly to writing her own analysis codes for mangrove data. She recently completed her senior year of high school at Atholton High School in Maryland and will begin undergraduate studies at Stanford University this fall.

"Working with Liza has been really amazing. She's very inspiring," said Fatoyinbo. "We had a lot of discussion with her and large international organizations that are interested in mangroves, and when we asked what would help them better implement their policies and procedures, we kept hearing about needing better change maps and better understanding what the drivers of change are. Liza took that and ran with it."

Goldberg plans to continue partnering with Fatoyinbo's team during her undergraduate studies.

"It's been an honor to work with Lola and her team for the last couple of years," Goldberg said. "It's rare to find an environment where people are so supportive regardless of your age and level of expertise, and it's been invaluable for my own research as I go into college. This environment is unique to NASA and to Goddard."

Researchers around the world are on the hunt to find cheaper, better lithium-ion battery materials to power large scale machines, such as electric vehicles. One of their goals is to find alternative lithium-metal-oxide electrodes to those containing cobalt, an element common within phone and laptop batteries but too expensive and short on capacity to propel electric vehicles over long distances.

For decades, researchers at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have taken part in the pursuit to uncover battery materials that perform as well as, if not better than, the ones we use today. Among the materials they’re investigating are manganese-rich compounds, because manganese is abundant and inexpensive; lithium-manganese oxides are also thermally safer to use, but not as energy dense as their cobalt counterparts.

“The ultimate goal is to make a structurally-stable, manganese-rich electrode for a lithium-ion battery that can give you long-time energy.” — Argonne scientist Jason Croy

The laboratory’s study of manganese-rich materials is shaped by the work that Argonne Emeritus Fellow Michael Thackeray has been doing since the early 1980s. While a postdoc at Oxford University in 1981-1982, Thackeray worked alongside battery scientist John Goodenough, one of the Nobel-prize winning architects of the modern lithium-cobalt-oxide battery.

Working together, Goodenough and Thackeray discovered a lithium-manganese-oxide electrode with a “spinel-type” structure that was cheaper and safer than the popular layered structure of lithium-cobalt-oxide Goodenough helped identify, though it suffered from inferior performance. A material “in spinel” is arranged in a cubic, close-packed 3D structure. Spinel electrodes have 3D channels to accommodate lithium quickly, and can therefore deliver high power, making them unique over the 2D layered and 1D tunnel electrode structures that other lithium-ion batteries adopt.

Goodenough and Thackeray’s spinel research, which Thackeray expanded when he joined Argonne in 1993, has transformed Argonne’s battery program to this day. In a recently published paper in Advanced Energy Materials, Thackeray discusses how their research on the structures and compositions of manganese-based lithium-metal oxides has evolved, and informs ongoing work today.

Building on their early work, Argonne researchers have developed a number of manganese-rich materials, including lithium-rich nickel-manganese-cobalt (NMC) cathodes, which Thackeray co-invented. Lithium-rich NMC is a breakthrough cathode technology that has provided noticeable improvements in performance and reliability over standard NMC compositions in lithium-ion technology. Argonne’s NMC technology has been licensed to manufacturers worldwide including General Motors, which adopted the cathode material in its Chevy Volt and Bolt models.

Thackeray and Goodenough’s work continues to inspire ongoing research at Argonne, where researchers are integrating spinel-type materials into cathodes at the nanoscale level, and are fine tuning spinel properties to engineer desirable properties within the cathode. For example, different spinel-type materials have been identified that can help stabilize NMC cathodes and aid the design of cathode and electrolyte materials for all-solid-state lithium-ion cells and batteries.

Argonne scientist Jason Croy and colleagues are intensifying work on a version of the NMC technology that boosts both the lithium and manganese content over currently used versions, ideally improving a battery’s energy density and safety while lowering costs. The improved technology is available for licensing.

“The ultimate goal of this research is to make a structurally-stable, manganese-rich electrode for a lithium-ion battery that can give you long-time energy,” Croy said. “The hope is that, by combining spinels with new materials, we’ll be able to develop new economically-viable options to cobalt- and nickel-rich materials.”

Stewart began looking at the effects of climate change on primate habitats with spatial data from the Coupled Model Intercomparison Project Phase 5, which estimates regional and seasonal temperature change per unit of CO2 emission, and range data of 426 separate primate species and subspecies, courtesy of the International Union for Conservation of Nature. Using these figures, she was able to project the effects current and estimated future global temperature increases would have on the precise territories that were home to particular primate species, based on projected emissions of CO2.

Specifically, she looked at annual average temperatures to see if they would exceed the pre-industrial seasonal maximum temperature (PSMT), or if they already had. In other words, she wanted to see how much hotter future average temperatures in a particular range would be than its hottest temperatures before carbon emissions began warming the planet.

To do this, she created individual range maps for each of the 426 species and subspecies of primates. She then estimated temperature increases as a direct result of the amount of CO2 emitted, measured in billions of tons.

According to her calculations, a 2˚C increase in global average temperatures above pre-industrial levels — the ceiling affirmed by the Paris Agreement — would lead to more than a quarter of all species ranges’ experiencing temperatures higher than those of pre-industrial times. For eight per cent of species, their entire current range would be significantly hotter than in the pre-industrial past.

“That’s where my assumption really gets its power,” she explains. “The maximum pre-industrial temperature under which these primates could function could have been a very brief period of time, for instance, the hottest week of the summer. But with this model, it becomes the average annual temperature.”

Hot, lazy, dangerous days

While two-thirds of primates still live in habitats with average temperatures below their PSMT, one-third are living in ranges that have experienced higher temperatures. That can spell serious trouble, especially if their ranges are particularly small.

“When it gets really hot, the primates need to rest in shade more. That means they can’t forage for food or socialize and play as much as they should,” she says. “Their food supply could also be at risk, and seasonal changes in temperature can even affect their reproductive cycles.”

She notes that nine species, several of them endangered and two critically so, are currently living in habitats that are entirely above their threshold temperature.

Her work has clearly impressed her supervisors. Turner says she is “a superb young researcher exploring scientific questions in animal behaviour while making her research relevant to conservation and sustainability. This study models potential climate change impacts on our closest animal relatives, and Brogan is continuing to bring together primates and sustainability issues in her current PhD research."

Hoping to help

Stewart is well aware that the struggle to mitigate the effects of climate change is not the work of a single individual, but rather a collaborative effort that requires sharing knowledge among researchers. She hopes the 426 maps she created for this paper will be of use to future colleagues.

“If someone is looking for specific data, I could send them my maps where I isolate different species in different areas,” she says. “It would be ideal if this research actually contributed to conservation efforts.”

The Natural Sciences and Engineering Research Council, Canada Graduate Scholarships (NSERC-CGS), the Fonds de recherche du Québec – Nature et technologie (FRQNT), Mitacs Globalink and the Quebec Centre for Biodiversity Science provided funding for this study.

Read the cited paper: “Climate change impacts on potential future ranges of non-human primate species.”

Journal

Climatic Change

DOI

10.1007/s10584-020-02776-5

CHAMPAIGN, Ill. -- Imagine reading by the light of an exploded star, brighter than a full moon - it might be fun to think about, but this scene is the prelude to a disaster when the radiation devastates life as we know it. Killer cosmic rays from nearby supernovae could be the culprit behind at least one mass extinction event, researchers said, and finding certain radioactive isotopes in Earth's rock record could confirm this scenario.

A new study led by University of Illinois, Urbana-Champaign astronomy and physics professor Brian Fields explores the possibility that astronomical events were responsible for an extinction event 359 million years ago, at the boundary between the Devonian and Carboniferous periods.

The paper is published in the Proceedings of the National Academy of Sciences.

The team concentrated on the Devonian-Carboniferous boundary because those rocks contain hundreds of thousands of generations of plant spores that appear to be sunburnt by ultraviolet light - evidence of a long-lasting ozone-depletion event.

"Earth-based catastrophes such as large-scale volcanism and global warming can destroy the ozone layer, too, but evidence for those is inconclusive for the time interval in question," Fields said. "Instead, we propose that one or more supernova explosions, about 65 light-years away from Earth, could have been responsible for the protracted loss of ozone."

"To put this into perspective, one of the closest supernova threats today is from the star Betelgeuse, which is over 600 light-years away and well outside of the kill distance of 25 light-years," said graduate student and study co-author Adrienne Ertel.

The team explored other astrophysical causes for ozone depletion, such as meteorite impacts, solar eruptions and gamma-ray bursts. "But these events end quickly and are unlikely to cause the long-lasting ozone depletion that happened at the end of the Devonian period," said graduate student and study co-author Jesse Miller.

A supernova, on the other hand, delivers a one-two punch, the researchers said. The explosion immediately bathes Earth with damaging UV, X-rays and gamma rays. Later, the blast of supernova debris slams into the solar system, subjecting the planet to long-lived irradiation from cosmic rays accelerated by the supernova. The damage to Earth and its ozone layer can last for up to 100,000 years.

However, fossil evidence indicates a 300,000-year decline in biodiversity leading up to the Devonian-Carboniferous mass extinction, suggesting the possibility of multiple catastrophes, maybe even multiple supernovae explosions. "This is entirely possible," Miller said. "Massive stars usually occur in clusters with other massive stars, and other supernovae are likely to occur soon after the first explosion."

The team said the key to proving that a supernova occurred would be to find the radioactive isotopes plutonium-244 and samarium-146 in the rocks and fossils deposited at the time of extinction. "Neither of these isotopes occurs naturally on Earth today, and the only way they can get here is via cosmic explosions," said undergraduate student and co-author Zhenghai Liu.

The radioactive species born in the supernova are like green bananas, Fields said. "When you see green bananas in Illinois, you know they are fresh, and you know they did not grow here. Like bananas, Pu-244 and Sm-146 decay over time. So if we find these radioisotopes on Earth today, we know they are fresh and not from here - the green bananas of the isotope world - and thus the smoking guns of a nearby supernova."

Researchers have yet to search for Pu-244 or Sm-146 in rocks from the Devonian-Carboniferous boundary. Fields' team said its study aims to define the patterns of evidence in the geological record that would point to supernova explosions.

"The overarching message of our study is that life on Earth does not exist in isolation," Fields said. "We are citizens of a larger cosmos, and the cosmos intervenes in our lives - often imperceptibly, but sometimes ferociously."

With the number of extreme weather days rising around the globe in recent years due to global warming, it is no surprise that there has been an upward trend in hospital visits and admissions for injuries caused by high heat over the last several years. But cold temperatures are responsible for almost all temperature-related deaths, according to a new study published in the journal Environmental Research.

According to the new study by researchers at the University of Illinois Chicago, patients who died because of cold temperatures were responsible for 94% of temperature-related deaths, even though hypothermia was responsible for only 27% of temperature-related hospital visits.

"With the decrease in the number of cold weather days over the last several decades, we still see more deaths due to cold weather as opposed to hot weather," said Lee Friedman, associate professor of environmental and occupational health sciences in the UIC School of Public Health and corresponding author on the paper. "This is in part due to the body's poorer ability to thermoregulate once hypothermia sets in, as well as since there are fewer cold weather days overall, people don't have time to acclimate to cold when those rarer cold days do occur."

Hypothermia, or a drop in the body's core temperature, doesn't require sub-arctic temps. Even mildly cool temperatures can initiate hypothermia, defined as a drop in body temperature from the normal 98.7 degrees to 95 degrees Fahrenheit. When this occurs, organs and systems begin to shut down in an effort to preserve the brain. The process, once started, can be very difficult to get under control; however, people who are more regularly exposed to lower temperatures are better able to resist hypothermia.

"People who were experiencing homelessness in the records we looked at were less likely to die from temperature-related injury," Friedman said. "Because they have greater outdoor exposure, they acclimate better to both heat and cold."

Heat-related issues are more likely to self-resolve by getting to a cooler place or by hydrating, Friedman said.

The researchers looked at inpatient and outpatient heat- and cold-related injuries that required a hospital visit in Illinois between 2011 and 2018. They identified 23,834 cold-related cases and 24,233 heat-related cases. Among these patients, there were 1,935 cold-related deaths and 70 heat-related deaths.

Friedman said government data systems that track temperature-related deaths significantly undercount these deaths.

"We found five to 10 times more temperature-related deaths by linking the hospital data to data from the National Weather Service and medical examiner's data," he said. "There are a lot more people dying from temperature-related injuries than is generally reported."

Friedman and his colleagues also found that cumulative costs associated with temperature-related hospital visits were approximately $1 billion between 2011 and 2018 in Illinois.

Adults older than age 65 and Black people were almost twice as likely to be hospitalized due to temperature-related injuries. Individuals who visited a hospital due to cold temperatures also commonly had multiple health issues, including electrolyte disorders, cardiovascular disease and kidney failure.

"Currently, the public health community focuses almost exclusively on heat injury. Our data demonstrate that improved awareness and education are needed around the risk for cold injuries, especially since there are fewer but more severe cold weather days -- leaving less chance for acclimation, which can be protective against hypothermia," Friedman said.

DURHAM, N.C. -- If you've ever been woken up before sunrise by the trilling and chirping of birds outside your window, you may have wondered: why do birds sing so loud, so early in the morning?

Researchers at Duke University say there may be a good reason why birds are most vocal at first light. By singing early and often, a new study suggests, birds perform better during the day.

The morning cacophony is mostly males, whose songs are meant to impress potential mates and rivals.

"It's like they're warming up backstage, before the sun comes up and the curtain rises," said co-author Stephen Nowicki, a biology professor at Duke.

Scientists have proposed various hypotheses for why birds do their most vigorous singing in the early morning hours. One idea is that it's the best time to broadcast, since there's little wind to distort their sound. Others have suggested that the dim light makes it difficult to do much else, like hunt for insects.

But a study in the journal Animal Behaviour points to another benefit: the early morning vocal warm-up works wonders for their singing.

To test the "warm-up hypothesis," Nowicki and Duke biologist Susan Peters recorded 11 male swamp sparrows between 2 a.m. and noon for two to three mornings each.

The song of the swamp sparrow is a simple trill of up to five notes, repeated around 5 to 10 times a second. "It sounds a bit like a melodious police whistle," Nowicki said.

Birdsong may look effortless, but it requires balancing competing demands of speed and dexterity, said first author Jason Dinh, a biology Ph.D. student who did the study while still an undergraduate at Duke.

Birds switch from one note to the next by opening and closing their beaks. To go from low to high and back down again in rapid-fire succession, a bird must precisely coordinate the movements of their beak and voice box with each breath.

To monitor the birds' performance, the researchers measured each bird's trill rate and vocal range over the course of the morning.

For swamp sparrows, the concert can start as early at 2:30 a.m. But they don't wake up singing like virtuosos, the study found.

Statistical analysis of the recordings revealed that they start off taking it easy; singing slower, or with a more limited range. They only start to nail their songs -- picking up the tempo and reaching for higher and lower pitch -- just after dawn, after hundreds of takes.

The more they warmed up, the better they got. "They're able to perform more difficult songs later in the morning," Dinh said.

While it's hard to make direct comparisons to the physiological effects in humans, Dinh said, the warm-up up may help get their blood flowing and temperature rising to meet the physical demands of singing.

Previous playback experiments by this research team have shown that a well-sung song, compared to a rusty one, is a bigger turn-on for females and more threatening to eavesdropping males, Peters said.

If male swamp sparrows see improvements in their singing within hours, the researchers say, the next step is to find out if females take note. If so, then males that sing early and often may have an advantage in attracting a mate.

Unlike living organisms, to avoid extinction, viruses need to hijack living host machineries to generate new viruses. The devastating respiratory virus, influenza A virus, utilize its hemagglutinin (HA) proteins to search for suitable host cells. Generally, HA has two important functions: selection of host cell and viral entry. Upon attaching to host cells, Influenza A virus are brought into host cells via endocytosis. A lipid bilayer cargo, known as endosome, carries influenza A virus from cell membrane into cytoplasm of host cell. Although the environment inside endosome is acidic, influenza A virus remains alive. More strikingly, HA undergoes structural change to mediate viral membrane to fuse with host endosomal membrane to form a hole in order to release viral components. Generation of this fusion event is elaborated as fusogenic, and hence structural changes of HA needed for this event is called as fusogenic transition. The mechanism of this event has been kept in Pandora's Box for decades despite extensive studies have been done to reveal its mystery. Now, Keesiang Lim and Richard Wong from Kanazawa University and colleagues have studied the molecular dynamic of HA using high-speed atomic force microscopy, a technique enabling real-time visualization of molecules on the nanoscale. The researchers were not only able to record the fusogenic transition of HA, but also observe its interaction with exosomes (a lipid bilayer cargo similar to endosome released by cells to outside environment).

The scientists initially observed the native conformation of HA under neutral physiological buffer, a condition that resembles to a neutral condition in host cell (a pH of 7.6). In this condition, HA was appeared as an ellipsoid, which is in agreement with findings generated by other tools such as X-ray crystallography and cryo-electron microscopy. Wong and colleagues have successfully recorded the fusogenic transition, which happening when HA was exposed to an acidic environment. Their HS-AFM results illustrated a transition of HA from an ellipsoid to a Y-shape together with declination of height and circularity/roundness of HA over time. The researchers reassure the conformational change happens because a particular subunit of HA became easily to be digested by trypsin after the transition.

To study how HA can facilitate the fusion between viral membrane and host endosome membrane, Wong and colleagues let HA interacted with exosomes, a lipid bilayer cargo that mimics endosome. The HA-exosome interaction is expected to be similar to HA-endosome interaction during membrane fusion. During the interaction, conformational change of HA was found again before its docked on an exosome. Fusogenic transition releases a particular peptide, known as fusion peptide, which later inserts into the exosomal membrane, enabling the HA molecule to embed on the membrane. The scientists also found evidences that the HA-exosome interaction caused deformation or rupture of exosome, leading to a 'leakage' of exosomal materials.

The findings of Wong and coworkers provide important insights for the mechanism of HA-mediated membrane fusion. In addition, their work also demonstrates the advantages of HS-AFM for studying biological processes. Lim and Wong exhilaratingly commented: "This study strongly suggests that HS-AFM is a feasible tool, not only for investigating the molecular dynamic of viral fusion proteins, but also for visualizing the interaction between viral fusion proteins and their target membranes."

[Background]

Influenza A hemagglutinin
Influenza A hemagglutinin (HA) is a protein residing on the surface of influenza A virus (the culprit that causes 'the flu' or influenza), playing a key role in viral infectivity. HA's functions include attaching influenza A virus to target cells and viral entry. After the virus attaches to its host cell, it is trapped in a lipid bilayer cargo known as endosome, and subsequently enters into host cytoplasm. This process is called as endocytosis. Acidic environment in endosome triggers structure changes of HA to allow HA to orchestrate fusion between viral membrane and host endosomal membrane. Finally, viral components can be released into host cells and new viruses will be made. The main target cells in human beings are typically located in the upper respiratory tract. Richard Wong from Kanazawa University and colleagues have now applied high-speed atomic force microscopy to study the fusogenic transition of HA, and the interaction of HA with lipid-bilayer membranes.

Atomic force microscopy
Atomic force microscopy (AFM) is an imaging technique in which the image is formed by scanning a surface with a very small and sharp tip. Horizontal scanning motion of the tip is controlled via piezoelectric elements, while vertical motion is converted into a height profile, resulting in a height distribution of the sample's surface. As the technique does not involve lenses, its resolution is not restricted by the so-called diffraction limit as in X-ray diffraction, for example. In a high-speed setup (HS-AFM), the method can be used to produce movies of a sample's structural changes in real time, as one biomolecule can be scanned in 100 ms or less. Wong and colleagues successfully applied the HS-AFM technique to study the fusogenic transition of HA, and how it fuses with the membranes of biological particles.

Hydrogenases can convert hydrogen just as efficiently as expensive platinum catalysts. In order to make them usable for biotechnological applications, researchers are deciphering how they work in detail. A team from Ruhr-Universität Bochum and the University of Oxford now reports in the journal Proceedings of the National Academy of Sciences (PNAS) that the transfer of protons and electrons by the enzyme takes place spatially separated, but is nevertheless coupled and thus, a decisive factor for efficiency. The article was published online on 10 August 2020.

Most efficient hydrogen producers

The so called class of [FeFe]-hydrogenases, which are for example found in green algae, are nature's most efficient hydrogen producers. They can both produce and split hydrogen. The actual chemical reaction takes place at the active site buried deep inside the enzyme. "The electrons and protons required for the reaction must therefore find an efficient way to get there," explains Dr. Oliver Lampret from the Photobiotechnology Research Group in Bochum, one of the authors of the paper. Electron transport takes place via an electric wire, so to speak, consisting of several iron-sulphur clusters. The protons are transported to the active centre via a proton transfer pathway consisting of five amino acids and one water molecule.

"Although it was known that there was a proton-coupled electron transfer mechanism, researchers had so far assumed that the coupling only takes place at the active centre itself," says Professor Thomas Happe, Head of the Photobiotechnology Research Group.

Protein engineering makes coupling visible

The team manipulated the hydrogenases in such a way that the proton transfer was significantly slower, but hydrogen could still be converted. Using dynamic electrochemistry, they showed that hydrogen conversion decreased significantly and more importantly, significant overpotentials were needed to catalyse the production or splitting of hydrogen. By manipulating the proton transfer pathway, the researchers had indirectly reduced the rate of electron transfer.

"As the two transfer routes are spatially separated, we assume that a cooperative long-range coupling of both processes is necessary for efficient catalysis," concludes Oliver Lampret. The findings should help to develop more efficient miniaturised hydrogenase catalysts in the future.

A new study from oceanographers at NOAA and the University of Miami Rosenstiel School's Cooperative Institute for Marine and Atmospheric Studies (CIMAS) has for the first time described the daily variability of the circulation of key deep currents in the South Atlantic Ocean. The research by the lead scientists based at the University of Miami's Rosenstiel School of Marine and Atmospheric Science (UM) and NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML) demonstrates strong variations in these key currents, changes that are linked to climate and weather around the globe.

The study, published in the journal Science Advances, found that the circulation patterns in the upper and deeper layers of the South Atlantic often vary independently of each other, an important new result about the broader Meridional Overturning Circulation (MOC) in the Atlantic.

"A key finding from this study is that our data showed that the ocean currents in the deepest parts of the South Atlantic Ocean behave differently than we thought before we had this new long-term dataset, which may have large implications for the climate and weather forecasts made by ocean models in the future," said Marion Kersale, an oceanographer with the UM Rosenstiel School's Cooperative Institute for Marine and Atmospheric Studies and lead author on the study.

The MOC is one of the main components of ocean circulation, which constantly moves heat, salt, carbon, and nutrients throughout the global oceans. Variations of the MOC have important impacts on many global scale climate phenomena such as sea level changes, extreme weather, and precipitation patterns.

The MOC consists of an upper cell of warmer, lighter waters that sits on top of colder, denser waters, known as the abyssal cell. These water masses travel around the global ocean, exchanging temperature, salinity, carbon and nutrients along the way.

This study provided remarkable insights into the full-depth vertical, horizontal, and temporal resolution of the MOC. A key new result from this study has been the estimation of the strength of the abyssal cell (from 3000 m to the seafloor), which previously have only been available as once-a-decade snapshot estimates from trans-basin ship sections.

This study found that the upper layer circulation is more energetic than that in the very deep, or abyssal, layer at all time scales ranging from a few days to a year. The flows in the upper and deep layers of the ocean behave independently of one another which can impact how the entire MOC system influences sea level rise and hurricane intensification in the Atlantic.

Research such as the study led by Kersale is helping oceanographers to refine and improve our understanding of the complexities of the MOC system. These observations will allow scientists to validate Earth system models and will aid in UM Rosentiel School and NOAA's goals to improve our understanding of the climate/weather system. 

Does urbanisation drive bumblebee evolution? A new study by Martin Luther University Halle-Wittenberg (MLU) and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig provides an initial indication of this. According to the study, bumblebees are larger in cities and, therefore, more productive than their rural counterparts. In "Evolutionary Applications", the research team reports that differences in body size maybe caused by the increasingly fragmented habitats in cities.

Over the last 200 years, the habitat of bumblebees and other insects has changed dramatically. Now they are less likely to live in rural areas but more likely to be surrounded by roads and concrete walls. "Living in a city can have both benefits and disadvantages for bumblebees. One the one hand, residential gardens and balconies, allotment gardens, botanical gardens and city parks provide rich food sources for bumblebees. On the other hand, cities are significantly warmer than their surrounding rural areas. In addition, impervious surfaces, streets and large buildings create considerably smaller habitats that are isolated from one another. These might pose a challenge to bumblebees," says Dr Panagiotis Theodorou from the Institute of Biology at MLU, who led the research at MLU and iDiv.

The team of biologists at MLU wanted to find out whether urbanisation is associated with shifts in bumblebee body size with consequences on the ecosystem service of pollination they provide. The scientists collected more than 1,800 bumblebees in nine German metropolitan areas and their rural surroundings and used potted red clover plants as reference for pollination in all locations. Their work concentrated on three locally common bumblebee species: the red-tailed bumblebee (Bombus lapidarius), the common carder bee (Bombus pascuorum) and the buff-tailed bumblebee (Bombus terrestris). The researchers measured the body size of every bumblebee they caught and counted the number of seeds produced per red clover plant. "Our results show that bumblebees from more fragmented urban areas were larger compared to their rural counterparts, by around four percent," says biologist Dr Antonella Soro from MLU. The results were similar for all three bumblebee species.

Body size is linked to an organism's metabolism, life history, space use and dispersal as well as a major determinant of species interactions, including pollination. "Larger bumblebees can see better, they have larger brains and they are better in learning and memory. They are also less likely to be attacked by predators and can travel greater distances, which is an advantage in a fragmented landscape such as the urban one. In addition, large bumblebees visit more flowers per flight and are capable of depositing a higher number of pollen grains on stigmas, which makes them better pollinators," says Soro. This might be the explanation of the positive relationship between body size and pollination documented by the researchers. The study gives an indication that the severity of habitat fragmentation could impact a bumblebee's body size and thus also indirectly influence pollination. According to Theodorou, there are still a lot of open questions regarding the effects of urban-related environmental changes on bees and pollination. Therefore, the team points to the importance of further studies to better understand the evolutionary responses of bees to urbanisation, information that can help improve urban planning.

Overallocation of surface water for growing food crops is shifting agriculture and other industry to use groundwater - which is much more difficult to measure and monitor.

Using local producer knowledge as 'soft data' to estimate groundwater use in modelling is a helpful tool in mapping sustainable use of scarce resources, Flinders University experts say.

Environmental and water researchers from Flinders have described the technique in a new paper published online in the Journal of Hydrology: Regional Studies.

The heavily agricultural La Vi River Basin in Vietnam was the focus of the study, forming part of a five-year project funded by the Australian Centre for International Agricultural Research (ACIAR).

"Groundwater use for food and industrial production is increasing globally, putting pressure on groundwater resources and associated ecosystems," says Flinders University Professor Okke Batelaan.

"In many countries, particularly in developing regions as well as Australia's Murray-Darling Basin (MDB), this abstraction may be poorly organised and not regularly gauged for data."

The researchers, including John Allwright fellow Flinders PhD candidate Manh Hai Vu, interviewed local farmers about their land use, agricultural practices and water use.

The approach was very helpful in collecting base line information for future use - particularly when climate change or variable rainfall pose a threat to future water management, says Dr Margaret Shanafield, from the National Centre for Groundwater Research and Training based at Flinders University.

"Although often thought of as a wet, tropical climate, Vietnam's South central coast has long dry seasons, and hence suffers from surface water shortages, similar to many parts of Australia," she says. "Groundwater use provides a significant solution to local farmers for producing cash crops and improving livelihood."

The system could also be used in Australia in areas such as the northern part of the MDB where groundwater is largely unmonitored.

The study developed a cost-effective and computationally simple solutions for estimating groundwater abstraction in data-poor agricultural regions, researchers say.

Patients with early onset psychosis may benefit from treatment for depression, including with anti-depressants alongside other medication, new research shows.

According to scientists at the University of Birmingham's Institute for Mental Health, depression may be an intrinsic part of early phase psychotic disorders that should be treated together with other more prominent symptoms to improve patient outcomes.

Depression is often identified alongside psychotic disorders such as schizophrenia in the early stages of the disorder, but is not currently routinely treated. In a new study, published in Schizophrenia Bulletin, the researchers set out to find out more about the associations between depression and psychosis, and particularly whether there were similarities in brain structure that could help future diagnostic pathways at an early stage.

Data was gathered from 1700 patients as part of the PRONIA study, a largescale European study which uses machine learning to find ways to predict how people with recent onset psychosis might recover.

The team used demographic and clinical data along with detailed symptom measures and neuroimaging information from a structural MRI scan from participants with recent onset psychosis and recent onset depression. They interrogated the data using machine learning software to try to find out whether it was possible to identify a subgroup of patients with distinct symptoms of both depression and psychosis.

Their results showed that, in fact, there was little difference in either the patients' depressive symptoms or in the structural brain changes in patients with depression, with and without psychosis. This shows that there is no subgroup of patients with both depression and psychosis, but rather that depression may be an intrinsic part of a majority of patients' psychosis.

The team argue their findings show that treatments focused on depression may well be an effective additional first-line treatment for psychosis, to be given alongside regular interventions.

Professsor Rachel Upthegrove, of the University of Birmingham's Institute for Mental Health, led the study. She says: "Our results suggest that depression is absolutely inherent in early phases of schizophrenia and so may one of the most important factors that we can target with treatments.

"We know that depression in patients with schizophrenia frequently leads to poorer outcomes, and so understanding how treatment such as antidepressant might be used to improve these outcomes could be a big step forward."

Paris Lalousis, a Priestly PhD Fellow at the University of Birmingham and the University of Melbourne, contributed to the study. He says: "Machine learning is a tool that has the potential to help solve the diagnostic and treatment conundrums that the complexity of mental health disorders present, and analyses using multimodal data are needed to advance the field. Our results show that using a principled approach and both psychopathological and biological factors can shed light into the experiences of patients with depression in early psychosis."

The team has already embarked on a clinical trial to test the approach in patients. The ADEPP trial will test people in the first stages of psychosis who take anti-depressants alongside anti-psychotic drugs. The trial will assess over a six month period whether the anti-depressants have an effect on the patients' ability to recover from their psychosis.

For the first time, researchers have found a way to describe conditions deep in the convection zone of "white dwarf" stars, which are home to some of the densest collections of matter in the Universe.

In a project conducted at the National Ignition Facility at Lawrence Livermore National Laboratory, the research team, including University of Rochester engineering professor Gilbert (Rip) Collins, simulated the crushing pressure created as stars cease to produce their own fuel, leaving only an extremely dense core.

"This is the first time we have been able to lock down an equation of state, describing the behavior of matter that is intrinsic to white dwarf stars, in particular the regime in a part of white dwarfs where oscillations occur that have been particularly difficult to model," says Collins, who was a coauthor on the team's paper published in Nature.

Collins is the director of science, technology, and academics at the Laboratory for Laser Energetics and is the Tracy Hyde Harris Professor of Mechanical Engineering and is a professor in the Department of Physics and Astronomy.

The results are important because they add to the growing body of evidence being collected by high-energy-density researchers about the formation and evolution of planets, stars, and other astrophysical bodies, which in turn can suggest possible approaches to creating novel materials in laboratories on Earth.

"Decades ago, underground nuclear tests made a couple of measurements in a similar regime, but now we're able to do this with a much higher level of accuracy and precision," says Collins.

Inwardly converging shock waves

White dwarf stars, sometimes called "star corpses" in popular literature, are what stars like our sun become after they have exhausted their nuclear fuel and expelled most their outer material. The process leaves behind a hot core that cools down over the next billion years or so, according to information from NASA's Goddard Space Flight Center. A white dwarf star the size of the Earth is 200,000 times as dense.

The density is achieved when the star is no longer able to create internal, outwardly directed pressure, because fusion has ceased. As that happens, gravity compacts the star's matter inward until even the electrons that compose the dwarf star's atoms are smashed together. One recent analysis has suggested that white dwarf stars are an important source of carbon found in galaxies.

To study the process, researchers fired nanometer laser light into a hohlraum--a tiny gold cylinder--bathing a spherical 1 mm sample of a carbon-based compound known as CH (methylidyne) in x-ray radiation heated to nearly 3.5 million degrees, at pressures ranging from 100 to 450 million atmospheres.

The experiments described in the paper simulate what happens in hot DQ white dwarf stars, first discovered in 2007, which contain a carbon and oxygen core surrounded by an envelope, or atmosphere, of mostly carbon. The researchers focused specifically on replicating the high pressure regimes that occur in an area of oscillating pulsations where previous attempts to model the behavior of matter have produced inconsistent results.

The paper describes how the x-ray radiation bath in the hohlraum is absorbed by an outer region (ablator) of the spherical fuel sample, which heats and expands, launching inwardly converging shock waves toward the center of sphere. The shocks coalesce into a single strong shock, traveling at a speed of 150 to 220 kilometers per second and traversing the sample in about 9 nanoseconds.