Earth

An international team of scientists lead by Professor Martina Havenith from Ruhr-Universität Bochum (RUB) has been able to shed new light on the properties of water at the molecular level. In particular, they were able to describe accurately the interactions between three water molecules, which contribute significantly to the energy landscape of water. The research could pave the way to better understand and predict water behaviour at different conditions, even under extreme ones. The results have been published online in the journal Angewandte Chemie on 19 April 2020.

Interactions via vibrations

Despite water is at first glance looking like a simple liquid it has many unusual properties, one of them being that it is less dense when it is frozen than when it is liquid. In the simplest way liquids are described by the interaction of their direct partners, which are mostly sufficient for a good description, but not in the case of water: The interactions in water dimers account for 75 per cent of the energy that keeps water together. Martina Havenith, head of the Bochum-based Chair of Physical Chemistry II and spokesperson for the Ruhr Explores Solvation (Resolv) Cluster of Excellence, and her colleagues from Emory University in Atlanta, US, recently published an accurate description of the interactions related to the water dimer. In order to get access to the cooperative interactions, which make up 25 per cent of the total water interaction, the water trimer had to be investigated.

Now, the team lead by Martina Havenith in collaboration with colleagues from Emory University and of the University of Mississipi, US, has been able to describe for the first time in an accurate way the interaction energy among three water molecules. They tested modern theoretical descriptions against the result of the spectroscopic fingerprint of these intermolecular interactions.

Obstacles for experimental research

Since more than 40 years, scientists have developed computational models and simulations to describe the energies involved in the water trimer. Experiments have been less successful, despite some pioneer insights in gas phase studies, and they rely on spectroscopy. The technique works by irradiating a water sample with radiation and recording how much light has been absorbed. The obtained pattern is related to the different type of excitations of intermolecular motions involving more than one water molecules. Unfortunately, to obtain these spectroscopic fingerprints for water dimers and trimers, one needs to irradiate in the terahertz frequency region. And laser sources that provide high-power have been lacking for that frequency region.

This technical gap has been filled only recently. In the current publication, the RUB scientists used the free electron lasers at Radboud University in Nijmegen in The Netherlands, which allows for high powers in the terahertz frequency region. The laser was applied through tiny droplets of superfluid helium, which is cooled down at extremely low temperatures, at minus 272,75 degrees Celsius. These droplets can collect water molecules one by one, allowing to isolate small aggregates of dimers and trimers. In this way the scientists were able to irradiate exactly the molecules they wanted to and to acquire the first comprehensive spectrum of the water trimer in the terahertz frequency region.

The experimental observations of the intermolecular vibrations were compared to and interpreted using high level quantum calculations. In this way the scientists could analyse the spectrum and assign up to six different intermolecular vibrations.

If a virus penetrates a cell, the immune system reacts immediately and produces the signalling protein interferon. This protein activates hundreds of highly specialised defence mechanisms in all surrounding cells, which can inhibit various steps in the replication of the virus. Even though these so-called interferon-stimulated genes form the backbone of the innate immune system, the mechanisms of action of only a few of them are understood as yet.

The interferon-stimulated gene C19orf66 plays an important role in the defence against hepatitis C viruses. A research team at Ruhr-Universität Bochum (RUB) headed by Professor Eike Steinmann from the Department for Molecular and Medical Virology has now studied how C19orf66 works. The results show that C19orf66 disrupts the formation of the viral replication machinery.

The researchers published their study on 12 April 2020 in the Journal of Hepatology.

Hepatitis C patients produce more of the gene than healthy individuals

"In order to find out whether the C19orf66 gene is increasingly activated in samples from hepatitis C patients, we first examined liver tissue samples from infected and healthy people," explains PhD student Volker Kinast. The analysis showed that the production of C19orf66 is increased in hepatitis C patients.

"In the next step, we checked whether C19orf66 has an antiviral effect against hepatitis C viruses. We conducted experiments using cells that contained a lot of C19orf66 and cells that contained only a little of it. We then observed that the hepatitis C virus replicates much more slowly in cells that contain a lot of C19orf66 than in control cells," says Kinast.

Virological and molecular biological analyses

Additional experiments with cells in which the gene C19orf66 was completely switched off confirmed: C19orf66 inhibits the replication of the hepatitis C virus. In order to understand how C19orf66 does this, the researchers conducted numerous virological and molecular biological analyses.

The results show that C19orf66 disrupts the formation of the viral replication machinery. The hepatitis C virus has the ability to manipulate liver cells in such a way that an accumulation of membrane vesicles occurs within the cell. The virus uses these membrane vesicles as a scaffold to replicate effectively. C19orf66 disrupts and alters the structure of the scaffold and thus inhibits the replication of the virus.

Many people don't know that they are infected

An estimated 71 million people have a chronical hepatitis C infection, and a large percentage of them are not aware of this fact. Over the years, the virus damages the liver, resulting in severe liver disease that often requires liver transplantation.

While considerable resources are invested in seasonal forecasts and early-warning systems for food security, not enough is known about El Niño's impact on the fisheries and aquaculture sectors, even though its name was given in the 1600s by fishers off the coast of Peru.

To remedy that, FAO is publishing, in partnership with French National Research Institute for Sustainable Development (IRD France), the report El Niño Southern Oscillation (ENSO) effects on fisheries and aquaculture. This report captures the current state of knowledge on the impacts of ENSO events across sectors, from food security to safety at sea, from fish biology and fishing operation to management measures.

El Niño is widely known as a climate pattern that begins over the Pacific Ocean but wreaks havoc on ecosystems in land and water far away from its origin. Its consequences include droughts and major harvest shortfalls in large swatches of Africa and Indonesia, forest fires in Australia, and serious flooding in South America.

ENSOs are often simplified to reflect two main phases: El Niño, an anomalous warming phase in the central and/or eastern equatorial Pacific Ocean, and an opposite cooling phase called La Niña.

In the former phase, a thickened surface layer of warm water prevents cold and nutrient-rich deep ocean water to reach the surface layer where photosynthesis occcurs, putting a break on ocean production. This lowers the availability of food to local fish species such as anchoveta, which in turn either migrate southwards or suffer a productivity collapse.

While understanding of ENSOs has developed greatly since the 1950s, researchers have also been stymied as its incidences are rarely similar. Adding to the complexity is that the frequency and intensity of these events appear to have intensified in the past two decades, with some climate models suggesting these trends may continue as the climate changes.

"ENSO is not just a binary phenomenon (either warm or cold). Every ENSO event is different in signal, intensity, duration, and so are their consequences," says Arnaud Bertrand, marine ecologist at IRD, who coordinated the report. "Understanding the diversity is key to developing predictive and preparatory capacities".

Key points :

International experts based in Chile, France and Peru were recruited to produce this report. It addresses successively the diversity of ENSO events; ENSO forecasting; ENSO in the context of climate change; global overview of ENSO impacts; Assessment of regional ENSO impacts on marine capture fisheries; coral bleaching and damage to reefs and related fisheries; ENSO and aquaculture; ENSO and inland capture fisheries.

Five broad types of ENSO were identified:

Extreme El Niño, Moderate Eastern Pacific (EP) El Niño, Moderate Central Pacific (CP) El Niño, Coastal El Niño, Strong La Niña. The authors also recognize that these five types are not static. ENSO events generally worsen with the effects of climate change on fish and fisheries, but the evidence is not yet conclusive enough.

For marine fisheries, the volume as well as the dominant species in fish catches can change dramatically depending on the type of ENSO. While the bulk of the net change is on Eastern Pacific fisheries, there are notable impacts on some fish populations in the Atlantic Ocean and some impact on tuna fisheries in the Indian Ocean. Further analysis of fish populations and sizes could shed light on longer-term effects as ENSO events alter habitats and marine food webs long after they are over.

Fostering nimble fishing techniques can contribute to resilience, as Peruvian fishers showed when they adjusted to catch more shrimp that moved into warmer waters and thus offset the missing anchoveta. At the same time, the authors note that El Niño events do not necessarily favour alternative species productivity of sardine and mackerel populations but rather increase their susceptibility to capture - relevant information for fisheries management systems in operation.

Evidence also suggests that ENSO events can significantly impact aquaculture output, particularly for marine plants, mollusks and crustaceans, while triggering shifts to more drought-resistance species in inland fisheries in countries such as Uganda.

Currently, reasonable forecasts can be made up to six months in advance, but with very little ability to predict which (ENSO) type will occur. ENSO has important impacts on cyclonic activity, ocean conditions or precipitation.

The authors conclude the report with perspectives for ENSO preparedness in a warmer world.

Just where fat is deposited in the body and to what degree a person may benefit from a lifestyle intervention depends, among other things, on how sensitive the brain is to insulin. If the person's brain responds sensitively to the hormone, a significant amount of weight can be lost, unhealthy visceral fat reduced, and the weight loss can be maintained over the long term. However, If the person's brain responds only slightly or not at all to insulin, the person only loses some weight at the beginning of the intervention and then experiences weight regain. Over the long term, the visceral fat also increases. These are the results of a long-term study by the German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Tübingen University Hospital which has now been published in Nature Communications.

To which extent body fat has an unhealthy effect depends primarily on where it is stored. If fat accumulates in the abdomen, this is particularly unfavorable. This is because the visceral fat releases numerous neurotransmitters that affect blood pressure, influence the secretion of the hormone insulin and can cause inflammation. This increases the risk of diabetes, cardiovascular disease and certain types of cancer. The subcutaneous fat which accumulates on the buttocks, thighs and hips has no adverse health effects. However, it is still unclear why fat storage does not occur in the same place in all people. Studies in the Tübingen Lifestyle Intervention Program (TULIP) [1] suggest that brain insulin responsiveness could play an important role here. They showed that people with a high insulin sensitivity in the brain benefit significantly more from a lifestyle intervention with a diet rich in fiber and exercise than people with insulin resistance in the brain. Not only did they lose more weight, they also had a healthier fat distribution. But how does insulin sensitivity affect the distribution of body fat and weight in the long term? Researchers from the German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Tübingen University Hospital investigated this question in a long-term study. For this purpose, they recorded the follow-up data of 15 participants over a period of nine years, in which the insulin sensitivity in the brain was determined by magnetoencephalography before the start of a 24-month lifestyle intervention.

High insulin sensitivity associated with reduction in visceral fat and weight

It was found that insulin action in the brain not only determines body weight, but also the distribution of fat in the body. "Subjects with high insulin sensitivity in the brain benefited from the lifestyle intervention with a pronounced reduction in weight and visceral fat. Even after the lifestyle intervention had ended, they only regained a small amount of fat during the nine-year follow-up," said the head of the study, Professor Martin Heni from Tübingen University Hospital. In contrast, people with brain insulin resistance only showed a slight weight loss in the first nine months of the program. "Afterwards, their body weight and visceral fat increased again during the following months of lifestyle intervention," said first author PD Dr. Stephanie Kullmann from the IDM.

Since the insulin action in the hypothalamus is crucial for the regulation of peripheral energy metabolism, the researchers also investigated how insulin sensitivity in this area of the brain is related to the distribution of body fat. For this purpose, they examined a cross-sectional cohort of 112 participants. The analysis of the data showed that people with high insulin sensitivity in the hypothalamus form little visceral fat. However, insulin sensitivity has no influence on the mass of subcutaneous fat.

Our study reveals a novel key mechanism that regulates fat distribution in humans. Insulin sensitivity in the brain determines where fat is deposited, "said Heni, summarizing the results. Since visceral fat not only plays a role in the development of type 2 diabetes, but also increases the risk of cardiovascular disease and cancer, the study results may also open up new approaches for treatment options beyond metabolic diseases. The researchers in Tübingen are already working on new therapies to abolish insulin resistance in the brain and thus have a beneficial effect on body fat distribution.

Data transmission that works by means of magnetic waves instead of electric currents - for many scientists, this is the basis of future technologies that will make transmission faster and individual components smaller and more energy-efficient. Magnons, the particles of magnetism, serve as moving information carriers. Almost 15 years ago, researchers at the University of Münster (Germany) succeeded for the first time in achieving a novel quantum state of magnons at room temperature - a Bose-Einstein condensate of magnetic particles, also known as a "superatome", i.e. an extreme state of matter that usually occurs only at very low temperatures.

Since then, it has been noticeable that this Bose-Einstein condensate remains spatially stable - although the theory predicted that condensate of magnons, which are attractive particles, should collapse. In a recent study, the researchers have now shown for the first time that the magnons within the condensate behave in a repulsive manner, which leads to the stabilization of the condensate. "In this way, we are resolving a long-standing contradiction between the theory and the experiment," says Prof. Sergej O. Demokritov who led the study. The results may be relevant for the development of future information technologies. The study was published in the journal Nature Communications.

Background and method:

What is special about the Bose-Einstein condensate is that the particles in this system do not differ from each other and are predominantly in the same quantum mechanical state. The state can therefore be described by a single wave function. This results, for example, in properties such as superfluidity, which is characterized by its zero dissipation during the motion of the condensate at low temperatures. The Bose-Einstein condensate of magnons is so far one of the few so-called macroscopic quantum phenomena that could be observed at room temperature.

Previously, the processes in the condensate had been studied exclusively in homogeneous magnetic fields - i.e. in magnetic fields that are equally strong at every point and in which the field lines point uniformly in one direction. As previously, using a microwave resonator, which generated fields with frequencies in the microwave range, the researchers excited magnons forming a Bose-Einstein condensate. In the current experiment, they, however, introduced an additional so-called potential well, which corresponds to inhomogeneous static magnetic field, which creates forces acting on the condensate. This enabled the scientists to directly observe the interaction of the magnons in the condensate.

For this purpose, they used a method of Brillouin light scattering spectroscopy. This involved recording the local density of the magnons with probing laser light focused on the surface of the sample. On this way, the researchers recorded the spatial redistribution of the condensate density at different experimental conditions. The collected data allowed to draw the firm conclusion that the magnons in the condensate interact in a repulsive manner, thereby keeping the condensate stable.

In addition, the researchers observed two characteristic times of dissipation, i.e. dissipation of energy and momentum from the condensate to other states. The time of momentum dissipation - the momentum describes the mechanical state of motion of a physical object - proved to be very long. "This may be the first experimental evidence for possible magnetic superfluidity at room temperature," emphasizes Sergej Demokritov.

Up to now, the use of condensates from magnetic particles has been made difficult mainly by the short lifetime of the condensate. "Our realization of moving condensate and investigation of magnon transport as well as discovery of two different times show that the life-time has nothing to do with the momentum dissipation of the moving condensate," says first author Dr. Igor Borisenko. The results could therefore open new perspectives for magnon applications in future information technologies.

The development of bimetallic nanoparticles (i.e., tiny particles composed of two different metals that exhibit several new and improved properties) represents a novel area of research with a wide range of potential applications. Now, a research team in the University of Maryland (UMD)'s A. James Clark School of Engineering has developed a new method for mixing metals generally known to be immiscible, or unmixable, at the nanoscale to create a new range of bimetallic materials. Such a library will be useful for studying the role of these bimetallic particles in various reaction scenarios such as the transformation of carbon dioxide to fuel and chemicals.

The study, led by Professor Liangbing Hu, was published in Science Advances on April 24, 2020. Research Associate Chunpeng Yang served as first author on the study.

"With this method, we can quickly develop different bimetallics using various elements, but with the same structure and morphology," said Hu. "Then we can use them to screen catalytic materials for a reaction; such materials will not be limited by synthesizing difficulties."

The complex nature of nanostructured bimetallic particles makes mixing such particles using conventional methods difficult, for a variety of reasons - including the chemical makeup of the metals, particle size, and how metals arrange themselves at the nanoscale.

This new non-equilibrium synthesis method exposes copper-based mixes to a thermal shock of approximately 1300 degrees Celsius for .02 seconds and then rapidly cools them to room temperature. The goal of using such a short interval of thermal heat is to quickly trap, or 'freeze,' the high-temperature metal atoms at room temperature while maintaining their mixing state. In doing so, the research team was able to prepare a collection of homogeneous copper-based alloys. Typically, copper only mixes with a few other metals, such as zinc and palladium - but by using this new method, the team broadened the miscible range to include copper with nickel, iron, and silver, as well.

"Using a scanning electron microscope and transmission electron microscope, we were able to confirm the morphology - how the materials formed - and size of the resulting Cu-Ag [copper-silver] bimetallic nanoparticles," Yang said.

This method will enable scientists to create more diverse nanoparticle systems, structures, and materials having applications in catalysis, biological applications, optical applications, and magnetic materials.

As a model system for rapid catalyst development, the team investigated copper-based alloys as catalysts for carbon monoxide reduction reactions, in collaboration with Feng Jiao, professor at the University of Delaware. The electro-catalysis of carbon monoxide reduction (COR) is an attractive platform, allowing scientists to use greenhouse gas and renewable electrical energy to produce fuels and chemicals.

"Copper is, thus far, the most promising monometallic electrocatalyst that drives carbon monoxide reduction to value-added chemicals," said Jiao. "The ability to rapidly synthesize a wide variety of copper-based bimetallic nanoalloys with a uniform structure enables us to conduct fundamental studies on the structure-property relationship in COR and other catalyst systems."

The non-equilibrium synthetic strategy can be extended to other bimetallic or metal oxide systems, too. Utilizing artificial intelligence-based machine learning, the new synthetic method will make rapid catalyst screening and rational design possible.

New York, NY (April 24, 2020) - A new WCS-led study reveals that mountain-dwelling species fleeing warming temperatures by retreating to higher elevations may find refuge from reduced human pressure.

A new study published in Nature Communications by scientists at WCS, the University of California, Berkeley, and the United States Forest Service shows that nearly 60 percent of all mountainous area is under intense human pressure. Most of the pressure is at low elevations and mountain bases, which tend to be easier places for people to live, grow food, and build roads. The scientists then used climate models to make predictions about how species would move under climate change. Based on their predictions, they found that species tend to move to higher elevations, and that these higher elevations tend to have more intact land for species because there is less human pressure.

Without factoring in human pressure, the authors warn that conservation actions may be misguided. Factoring in human pressure reveals the true 'shape' of a mountain for species that are restricted to intact landscapes, which are often the species of greatest conservation concern. Here, the 'true shape' refers to how much land area is potentially available as habitat for a species as it moves up in elevation, not simply how much total land area is available. The true shape can reveal where species will tend to lose versus gain intact land area as they shift under climate change: the elevations where species are expected to lose area represent the priority zones for conservation.

Mountains are home to over 85 percent of the world's amphibians, birds, and mammals, making them global conservation priorities. But mountain-dwelling species are at risk from human activities, such as agriculture, livestock grazing, and development that reduce their habitat, and climate change that threatens to push species upslope as they struggle to find tolerable temperatures.

"Species are adapted to certain temperature conditions. As temperatures warm in mountains, scientists have documented species moving to higher elevations to maintain the same temperatures," said Paul Elsen, a WCS Climate Adaptation Scientist and lead author of the study. "This was always seen as a problem, because species would have less land area and less habitat to occupy at high elevations. But what we found is that as species move upslope, they tend to move away from areas that are already under intense human pressure and into areas with reduced human pressure. As a result, they can occupy more intact land area, even if the total amount of land area declines."

The authors combined several global databases to make their assessments: high-resolution digital elevation models gave a picture about how much surface area is available at different elevations. The Human Footprint Index provided information on pressure from human activities. Global climate models projected how temperatures are likely to change by the late 21st century.

The authors then used computer simulations to place hundreds of thousands of hypothetical 'species' across all mountain ranges at different elevations and then predicted how they would shift their ranges based on climate projections. For each simulation, they compared the amount of area the species had to begin with to the amount they would have after the range shift under climate change.

Said Elsen: "We were surprised to find that many species had more intact land area available after the range shift compared to when they started."

The results suggest that many species in mountain ranges may have more intact land area available in the future if they track warming temperatures to higher slopes, though there were exceptions.

"Our results offer a glimmer of hope for montane species under climate change," Elsen said. "Montane species are still facing tremendous human pressure, especially at low elevations, but we have the opportunity now to protect intact habitats at higher elevations to give these species the best possible chance going forward."

Scientists in Texas and Pennsylvania have identified a protein sensor that restricts how much sugar and fat our cells convert into energy during periods of starvation. It is possible, the scientists say, that the sensor could be fine-tuned to prompt more sugar and fat conversion in people with metabolic conditions such as diabetes, obesity and cardiovascular disease who need help trimming down and living a healthier lifestyle.

The study was published April 21 in the journal Science Signaling.

Senior author Madesh Muniswamy, Ph.D., from the Long School of Medicine at The University of Texas Health Science Center at San Antonio, is an expert in the function and properties of mitochondria. These are the cell structures that convert sugar and fat into chemical energy called ATP.

“We want to offer, in the future, a solution to the metabolic crisis faced by millions of people across the world,” Dr. Muniswamy said. “Millions of people consume too much food, while millions of others are in poverty and subsist on too little food. We are studying what happens at the molecular level in both situations with a goal of developing a drug to intervene.”

Speed of conversion

Our bodies continuously move things from cell to cell with what are sort of like roadways and cars. The vehicle required for fat and sugar conversion is called the mitochondrial calcium uniporter, or MCU. Like traffic moving people to destinations, the speed at which the MCU moves the energy is essential. If it is too slow, conditions such as obesity appear. If it is too fast, malnourishment results.

Driving a regulated speed limit at all times is desirable for proper health, Dr. Muniswamy said.

Keeper of the road

In the Science Signaling article, Dr. Muniswamy and colleagues describe another key component that, like a traffic police officer, regulates this roadway activity.

“We identified a mitochondrial protein called MICU1 that functions as a gatekeeper of this roadway,” Dr. Muniswamy said.

When nutrient levels are low, MICU1 clamps down on the channel activity to prevent excess energy transaction. “When you’re starving, you want to live longer, you don’t want to burn all the sugar and the fat you have, so MICU1 slows down the activity,” Dr. Muniswamy said.

The opposite is also true — if the roadway traffic is driving too slowly, MICU1 can rev it up.

Relieve conditions

“In the future, we might design a new drug to control this pathway to basically alleviate many cardiovascular- and metabolic syndrome-related diseases,” Dr. Muniswamy said. “That’s our plan.

“When you speed up the channel, all the sugar and fat will be burned, and you slim down,” he added.

Acknowledgments

The research involves multiple faculty and staff of the Department of Medicine and the Center for Renal Precision Medicine, both within the Long School of Medicine at UT Health San Antonio. Collaborators are from the Lewis Katz School of Medicine at Temple University, the Penn State University College of Medicine and Cedars-Sinai Medical Center in Los Angeles.

Coauthors in the Long School of Medicine are W. Brian Reeves, M.D.; Kumar Sharma, M.D.; Luke Norton, Ph.D.; Subramanya Srikantan, Ph.D.; Madesh Muniswamy, Ph.D.; Cassidy C. Daw; Travis R. Madaris; Karthik Ramachandran, Ph.D.; Benjamin T. Enslow; Cherubina S. Rubannelsonkumar; Soumya Maity, Ph.D.; Pragya SinghMalla; and Christopher E. Shannon, Ph.D. Dr. Muniswamy is the corresponding author. Coauthor from the School of Dentistry at UT Health San Antonio is Brij B. Singh, Ph.D.

Funding is from the National Institutes of Health and U.S. Department of Defense.

Citation

Mitochondrial pyruvate and fatty acid flux modulate MICU1-dependent control of MCU activity

By Neeharika Nemani, Zhiwei Dong, Cassidy C. Daw, Travis R. Madaris, Karthik Ramachandran, Benjamin T. Enslow, Cherubina S. Rubannelsonkumar, Santhanam Shanmughapriya, Varshini Mallireddigari, Soumya Maity, Pragya Singhmalla, Kalimuthusamy Natarajanseenivasan, Robert Hooper, Christopher E. Shannon, Warren G. Tourtellotte, Brij B. Singh, W. Brian Reeves, Kumar Sharma, Luke Norton, Subramanya Srikantan, Jonathan Soboloff, Madesh Muniswamy

SCIENCE SIGNALING 21 APR 2020

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Journal

Science Signaling

DOI

10.1126/scisignal.aaz6206

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More on this News Release

Traffic officer protein governs speed of sugar/fat conversion pathway

University of Texas Health Science Center at San Antonio

Journal
Science Signaling
Funder

US Department of Defense,
National Institutes of Health

DOI
10.1126/scisignal.aaz6206

Keywords

/Life sciences/Biochemistry/Biomolecules/Carbohydrates/Sugars

/Life sciences/Cell biology/Cellular physiology/Cell metabolism/Cellular energy

/Scientific community/Research programs/Cancer research

Original Source

https://news.uthscsa.edu/traffic-officer-protein-governs-speed-of-sugar-fat-conversion-pathway/

During the past few weeks, empty supermarket shelves, without pasta, rice and flour due to panic buying, has caused public concerns about the possibility of running out of food. Australian farmers have reassured consumers saying that the country produces enough food to feed three times its population. However, will this statement remain true in ten to twenty years in a country severely affected by climate change? The answer is yes, if we are prepared for this and if there is continuous funding towards creating solutions to increase crop production.

"Plant scientists are punching above their weight by participating in global, interdisciplinary efforts to find ways to increase crop production under future climate change conditions. We essentially need to double the production of major cereals before 2050 to secure food availability for the rapidly growing world population," says ANU Professor Robert Furbank from the ARC Centre of Excellence for Translational Photosynthesis (CoETP).

"It is similar to finding a virus vaccine to solve a pandemic, it doesn't happen overnight. We know that Australia's agriculture is going to be one area of the world that is most affected by climate extremes, so we are preparing to have a toolbox of plant innovations ready to ensure global food security in a decade or so, but to do this we need research funding to continue," Professor Furbank says.

Several examples of these innovative solutions were published recently in a special issue on Food Security Innovations in Agriculture in the Journal of Experimental Botany, including five reviews and five research articles.

Co-editor of the Special Issue, ANU Professor John Evans, says that this publication highlights the now widely accepted view that improving photosynthesis - the process by which plants convert sunlight, water and CO2 into organic matter - is a new way to increase crop production that is being developed.

"We are working on improving photosynthesis on different fronts, as the articles included in this special issue show, from finding crop varieties that need less water, to tweaking parts of the process in order to capture more carbon dioxide and sunlight. We know that there is a delay of at least a decade to get these solutions to the breeders and farmers, so we need to start developing new opportunities now before we run out of options," says Professor Evans, CoETP Chief Investigator.

The special issue includes research solutions that range from traditional breeding approaches to ambitious genetic engineering projects using completely different ends of the technological spectrum; from robot tractors, to synthetic biology. All these efforts are focused on finding ways to make crops more resistant to drought and extreme climate conditions and being more efficient in the use of land and fertilisers.

"Our research is contributing to providing food security in a global context, and people often ask what that has to do with Australian farmers and my answer is everything. Aside from the fact that economy and agriculture are globally inter-connected, if Australian farmers have a more productive resilient and stable crop variety, they are able to plan for the future, which turns into a better agribusiness and at the same time, ensures global security across the world," says Professor Furbank.

Researchers at Baylor College of Medicine reveal that astrocytes, the most abundant cells in the brain, play a direct role in the regulation of neuronal circuits involved in learning and memory. The findings appear in the journal Neuron.

"It has become increasingly clear that astrocytes are much more than supportive cells in the healthy adult brain. They play a direct role in a wide variety of complex and essential functions, including neuronal communication through synapses and regulation of neural circuit functions," said corresponding author Dr. Benjamin Deneen, professor of neurosurgery and a member of the Center for Stem Cell and Regenerative Medicine at Baylor. "In this study, we show a new role of astrocytes in normal brain function."

Previous work showed that astrocytes comprise diverse populations with unique cellular, molecular and functional properties. They occupy distinct brain regions, indicating regional specialization. There is evidence suggesting that transcription factors - proteins involved in controlling gene expression - regulate astrocyte diversity. Deneen and his colleagues looked to get a better understanding of the role transcription factor NFIA, a known regulator of astrocyte development, played in adult mouse brain functions.

The researchers worked with a mouse model they had genetically engineered to lack the NFIA gene specifically in adult astrocytes in the entire brain. They analyzed several brain regions, looking for alterations in astrocyte morphology, physiology and gene expression signatures.

"We found that NFIA-deficient astrocytes presented defective shapes and altered functions," said Deneen, who holds the Dr. Russell J. and Marian K. Blattner Chair and is a member of the Dan L Duncan Comprehensive Cancer Center at Baylor. "Surprisingly, although the NFIA gene was eliminated in all brain regions, only the astrocytes in the hippocampus were severely altered. Other regions, such as the cortex and the brain stem, were not affected."

Astrocytes in the hippocampus also had less calcium activity - calcium is an indicator of astrocyte function - as well as a reduced ability to detect neurotransmitters released from neurons. NFIA-deficient astrocytes also were not as closely associated with neurons as normal astrocytes.

Importantly, all these morphological and functional alterations were linked to defects in the animals' ability to learn and remember, providing the first evidence that astrocytes are to some extent controlling the neuronal circuits that mediate learning and memory.

"Astrocytes in the brain are physically close to and communicate with neurons. Neurons release molecules that astrocytes can detect and respond to," Deneen said. "We propose that NFIA-deficient astrocytes are not able to 'listen' to neurons as well as normal astrocytes, and, therefore, they cannot respond appropriately by providing the support needed for efficient memory circuit function and neuronal transmission. Consequently, the circuit is disrupted, leading to impaired learning and memory."

The widely reported "insect apocalypse" is far more nuanced than previous studies have suggested, according to a new study, which reports the findings of a meta-analysis featuring data from 166 long-term surveys across 1,676 sites worldwide. The results demonstrate that global insect population trends are highly spatially variable and reflect both decline and growth. Insects are among the most abundant and diverse animals on the planet and serve a critical role for ecosystem services and in the food web. Several recent case studies have reported drastic declines in insect abundance and species richness - with some global regions estimating biomass losses as high as 25% per decade. When extrapolated globally, such findings paint an apocalyptic picture for Earth's insects, a suggestion that has sparked serious concern among policymakers, scientists and the public. However, despite the alarm, insects are critically understudied and it remains uncertain just how widespread these patterns of decline are. To address this, Roel van Klink and colleagues evaluated a comprehensive dataset of long-term insect surveys from sites across the globe - what Maria Dornelas and Gergana Daskalova call "the largest and most complete assessment to date," in a related Perspective. The analysis by van Klink and colleagues revealed considerable variation in insect population trends, even among adjacent sites. Although highly variable, van Klink et al. report an average decline in terrestrial insect abundance of roughly 9% per decade, which, while lower than other published rates, confirms the general trend. On the other hand, their data also revealed an increase in the abundance of freshwater insects at a rate of nearly 11% per decade, perhaps partly due to successful clean water efforts. "As we continue to tackle challenges in disentangling different insect biodiversity trends, we will be better poised to predict their consequences for ecosystem function and services, such as pollination, decomposition and pest control," write Dornelas and Daskalova.

The discovery of the earliest known modern amphibians in Antarctica provides further evidence of a warm and temperate climate in the Antarctic Peninsula before its separation from the southern supercontinent, Gondwana. The fossils, which belong to the family of helmeted frogs, are described in Scientific Reports this week.

Thomas Mörs and colleagues discovered the fossilized remains of a hip bone and ornamented skull bone during expeditions to Seymour Island, Antarctica Peninsula, between 2011 and 2013. The specimens are approximately 40 million years old and from the Eocene period, and both belong to the Calyptocephalellidae family, also known as helmeted frogs. No traces of cold-blooded amphibians or reptiles from families still in existence had been found to date in Antarctica.

Previous evidence suggests that ice sheets formed across the Antarctic Peninsula before the final break-up of the southern supercontinent Gondwana into continents of the present-day Southern Hemisphere, including South America and Antarctica. The new discovery suggests that the climatic conditions of the Antarctic Peninsula during the late middle Eocene may have been comparable with the humid and temperate climate in the forests of South America today, where all five living species of helmeted frog are exclusively found.

The findings indicate that the forests of South America may be a modern analogue of the Antarctic climate just prior to the glaciation of the southern continent and may now be home to species originally found across the Antarctic Peninsula.

A new way of looking at marine evolution over the past 540 million years has shown that levels of biodiversity in our oceans have remained fairly constant, rather than increasing continuously over the last 200 million years, as scientists previously thought.

A team led by researchers from the School of Geography, Earth and Environmental Sciences at the University of Birmingham have used a big data approach to study this question, which has been disputed by palaeobiologists in recent years.

Using fossil data collected over the past two centuries, and compiled by hundreds of researchers in the Paleobiology Database over the last 20 years, the team was able to show regional-scale patterns of diversity across geological time from the so-called Cambrian Explosion - the point at which most major groups of animals started to appear in the fossil record - to the present day. Their results are published today in Science.

Dr Roger Close, who led the research, explains: "Studies of marine animal diversity over the last five-hundred-odd million years have historically focussed on estimating how "global" diversity changed through time. The problem is that the fossil record is not really global, because both the amount and the parts of the world that are actually preserved in the fossil record changes so much through geological time. This means that so-called "global" diversity curves are misleading."

"To get around this problem, we studied diversity at regional spatial scales. This meant that we could focus on places and times that are well-known in the fossil record. By comparing geographic regions that were similar in size, we could show how marine animal diversity varied across both time and space."

Using these estimates for specific geographic regions, the team was also able to estimate the influence of other environmental factors, such as coral reef systems. At this more localised level, it's possible to see significant variations in diversity across the globe within time intervals, perhaps in response to environmental differences.

"We think of reefs today as being hotspots of diversity, responsible for housing a disproportionate amount of animal species," says Dr Close. "So in areas where there are a higher proportion of reefs, diversity will inevitably be higher."

"Importantly, though we don't find any evidence that diversity increased in a continuous, sustained way through long intervals of geological time. This is a major departure from previous studies of "global" diversity. These studies concluded that marine animal biodiversity had increased steadily over the last 200 million years, culminating in modern levels that were greater than any point in Earth's history. In contrast, our work suggests that modern levels of biodiversity -- at least at the regional scales we studied -- are not exceptional."

Interestingly, the researchers did observe one point in the fossil record where there was a step change in diversity. The team found this evidence at the end of the Cretaceous period, when the dinosaurs became extinct.

"Not long after this devastating mass extinction, we see a distinct shift towards greater regional diversity. This probably had something to do with ecological reorganisation after many species were wiped out. In particular, we see a rebound to much higher diversity among gastropods - a huge group of invertebrates that we would recognise as snails and slugs. This suggests that such a widespread species loss cleared space for other groups to explode - and gastropods were able to take advantage of this," says Dr Close.

"When you look at these individual animal groups, you can see fluctuations in diversity that are often substantial. But taken together, these patterns sum to one of constrained diversity. Some groups might benefit from the misfortune of others, but the overall levels of diversity that we see have remained fairly stable for hundreds of millions of years."

Researchers have unveiled the precise shape of a key player in human metabolism, which could open the door to better treatments for obesity and other metabolic disorders.

The research, scheduled to publish April 24 in the journal Science, centered on a protein in the brain called the melanocortin 4 receptor, or MC4R. This receptor plays a crucial role in regulating the body's energy balance by controlling how much energy is stored as fat.

Mutations in the gene that encodes the MC4R protein are the most common genetic cause of early-onset obesity, affecting approximately 1 in every 1,500 people.

Raymond Stevens, director of the Bridge Institute in the University of Southern California Michelson Center for Convergent Bioscience and founding director of the iHuman Institute at ShanghaiTech University, was interested in the MC4R as part of a larger effort to elucidate the structures of a class of proteins called G protein-coupled receptors, of which MC4R is a member.

As Stevens and his team began to tackle the MC4R structure, they turned to Roger Cone and his colleagues at the University of Michigan Life Sciences Institute.

Scientists in the Cone lab discovered the MC4R and have been studying its biology and pharmacology for more than 25 years. In that time, at least four drugs have been developed to target melanocortin receptors in humans. One of these drugs, setmelanotide, acts at the MC4R to treat rare forms of syndromic obesity. But it is not potent enough to treat more common forms of obesity--such as dietary obesity--explained Cone, who was a senior author of the study.

Working across the three institutions, researchers Yu Jing and Luis Gimenez led the team in determining the structure of the MC4R--and uncovered some unexpected characteristics of the protein that shed new light on how it binds to and interacts with other molecules.

For example, they found a calcium ion binding to both the MC4R and to the primary molecule that the receptor binds. This instance of the bound calcium ion was a first for Stevens and his group, who have determined the structures of many members of this large class of proteins.

"At first it seemed like more of a scientific curiosity. But then further experiments revealed that the calcium is actually required for the function of the receptor," said Stevens, who also was a senior author of the study. "Imagine a lock and key situation; in this case, we found that there's a large key and a small key, and we need both of them to unlock the receptor."

Lex Van Der Ploeg, former chief scientific officer of Rhythm Pharmaceuticals, the company that developed setmelanotide, believes the findings open a new path to structure-based design of agonists and antagonists for the melanocortin receptor family.

"These discoveries can enable the development of melanocortin receptor targeted pharmaceuticals for diverse therapeutic applications," said Van Der Ploeg, who did not participate in this study.

Cone and Stevens highlight the findings as an example of the importance and power of international collaboration.

"We were able to contribute our knowledge of the MC4R to help further the structural biology studies," said Cone, who serves as director of the LSI and a professor of molecular and integrative physiology at the U-M Medical School. "And key structural findings from the USC and ShanghaiTech researchers are helping us answer more questions about how this receptor functions in human metabolism."

There has been a dramatic decrease in cold-water plankton during the 20th century, in contrast to thousands of years of stability, according to a new UCL-led study.

The research, published in Geophysical Research Letters, analysed the fossilised remains of plankton, sampled from the Northeast Atlantic Ocean, south of Iceland. The scientists uncovered a striking change in the types of species that inhabit these waters.

Lead author of the study, Dr Peter Spooner (UCL Geography), said: "The Northeast Atlantic is of crucial importance for the global climate system and marine ecosystems. In this study, we provide the first evidence that Northeast Atlantic circulation in the 20th century was unusual compared to the last 10,000 years.

"This change in Northeast Atlantic circulation caused a replacement of cool, subpolar waters with warmer subtropical waters near Iceland, and has impacted the distribution of marine organisms, particularly plankton. The most striking aspect of our work is the exceptional nature of the shift in the 20th century, in contrast to thousands of years of relative stability, with implications for understanding future change."

The research builds on earlier work which examined how the North Atlantic conveyor circulation has been changing over the industrial era, and was a collaboration with Woods Hole Oceanographic Institution (USA), the Scottish Association of Marine Science, and the University of Edinburgh. The scientists analysed around 150,000 specimens of planktonic foraminifera, tiny single-celled creatures that float in ocean waters.

They compared how different species of plankton fared over a 10,000 year period, using sediment from the bottom of the ocean to reconstruct how the Northeast Atlantic has changed.

They found that between around 6000 BC and 1750 AD, the region was dominated by Turborotalita quinqueloba, a species of plankton that prefer cooler waters (representing around 40% of all species of floating foraminifera).

However, during the 20th century the relative abundance of the species declined dramatically and was replaced by a transitional (warmer water) type of plankton, such as N. incompta and G. glutinata.

Co-lead author Dr David Thornalley (UCL Geography) said, "We are too used to thinking of the North Atlantic as being dominated by natural cycles that last decades. But this is only because direct observations do not go back far enough. These new records allow us to put our observations into a much longer-term context, and reveal the exceptional nature of what has happened in the 20th century."

As well as the change from cold to warmer species, the team found indicators of changing nutrient and food availability, all suggesting that waters from the subtropics were making their way to Iceland.

The findings correlate with other records from across the North Atlantic, which suggest that ocean warming and nutrient changes, driven by increased freshwater into the North Atlantic Circulation Belt, are likely to be the main culprit. The authors argue the evidence all points to changing ocean circulation.

Dr Spooner added: "The end of the Little Ice Age may have triggered a freshwater input early in the industrial era. And with climate change today, we are seeing more freshwater entering the Atlantic, through melting ice, increasing rainfall and pulses of freshwater from the Arctic Ocean."

The habitats of marine species, from plankton and fish to whales, are governed by ocean circulation, temperature and food. The research highlights that not only plankton has been affected.

Dr Spooner said: "Fisheries data only goes back so far, and it is difficult to separate the effects of overfishing from those of climate change, but for some species such as mackerel, which is now being regularly fished around Iceland, it seems clear that the changes we have seen are having a profound impact on where it can be found.

Professor Murray Roberts (University of Edinburgh), ATLAS project coordinator, concluded: "We know that ocean circulation in the area can affect the whole ecosystem, all the way up to top predators such as pilot whales. If the ocean has changed this much in the last hundred years - which we usually think of as being quite a stable period - it is absolutely essential we understand the implications before new human activities like deep-sea mining are allowed to begin."