Scientists zero in on the life-threatening fungus, Candida auris' ability to stick

In 2009, a mysterious fungus emerged seemingly from out of thin air, targeting the most vulnerable among us. The fungus in question poses a very real threat. Scientists are trying to figure out what makes the life-threatening fungus Candida auris tick—and why even the best infection control protocols in hospitals and other care settings often fail to get rid of it.

Researchers have now zeroed in on C. auris' uncanny ability to stick to everything from skin to catheters and made a startling discovery.

They discovered that C. auris is unlike any other known fungus in that it employs a type of protein, called an adhesin, that acts very similar to those used by oceanic organisms, such as barnacles and mollusks.

The new adhesin is only present in C. auris so we don't know where it came from evolutionarily. It doesn't look like it came from any other organisms by sequence similarity. The bonds formed by Scf1, they revealed, are cation-pi bonds, which are among the strongest non-covalent chemical bonds in nature.

Furthermore, the team discovered that SCF1 was associated with increased colonization and an enhanced ability to cause disease. Using mouse models, they demonstrated that a loss of both SCF1 and IFF4109 diminished the ability of a strain of C. auris to colonize skin and an in-dwelling catheter. What's more, strains designed to over express SCF1 saw enhanced virulence and more fungal lesions.

It could be that adhesin is required to get attached to blood vessels,  or maybe it changes the host-receptor interactions which has been true for the related fungus Candida albicans, but we don't know in this case yet.

Darian J. Santana et al, A Candida auris –specific adhesin, Scf1 , governs surface association, colonization, and virulence, Science (2023). DOI: 10.1126/science.adf8972

Researchers find a cancer enhancer in the genome that drives tumor cell growth

Researchers have found that cancer cells can enhance tumor growth by hijacking enhancer DNA normally used when tissues and organs are formed. The mechanism, called enhancer reprogramming, occurs in bladder, uterine, breast and lung cancer, and could cause these types of tumors to grow faster in patients.

The results also pinpoint the role that specific proteins play in regulating the enhancer region which may lead to improved treatments for these cancer types. Living cells, even cancer cells, follow instructions in the genome to turn genes on and off in different contexts. The genome is like a recipe book written in DNA that gives instructions on making all the parts of the body. In each organ, only the recipes relevant to that organ should be followed, whether it's the instructions for lung, breast or some other tissue. Like flipping pages in a recipe book, the DNA containing the instructions for turning genes on in the lung is open and used in the lung, for example, but closed and ignored in other types of cells.

Scientists know that some cancer cells are opening the wrong pages in the recipe book—ones that contain the SOX2 gene, which can cause tumours to grow uncontrollably. They wanted to find out: how does the gene become expressed in cancer cells?

The researchers analyzed genome data to look for enhancer DNA that could activate SOX2 in cancer cells. The enhancer they found is open in many different types of patient tumors, meaning this could be a cancer enhancer active in bladder, uterus, breast and lung tumors. Unlike many cancer-causing changes, this enhancer reprogramming mechanism does not arise out of mutation due to DNA damage; it is caused by part of the genome opening when it should be staying closed.

The researchers then determined that the enhancer causes increased cancer cell growth because when they removed the enhancer in lab-grown cells, the cancer cells created fewer new tumour colonies.

Part 1

To figure out why cells have a DNA region that makes cancer worse, the team generated mice without this DNA region, and found these mice do not form a separate passage for air and food in their throat as they develop. Thus, this potentially dangerous cancer-enhancer region is likely in the human genome to regulate airway formation as the human body forms. However, if a developing cancer cell opens this region, it will form a tumor that grows faster and is more dangerous for the patient.

The researchers also found that two proteins known to have a role in the developing airways, FOXA1 and NFIB, are now regulating SOX2 in breast cancer.

The enhancer is activated by the FOXA1 protein and suppressed by the NFIB protein. This means that drugs suppressing FOXA1 or activating NFIB may lead to improved treatments for bladder, uterine, breast and lung cnacer.

Now that scientists know how the SOX2 gene is activated in certain types of cancers, they can look at why this is happening by asking,  "Why did the cancer cells end up on the wrong page of the genome recipe book?"

Luis E Abatti et al, Epigenetic reprogramming of a distal developmental enhancer cluster drives SOX2 overexpression in breast and lung adenocarcinoma, Nucleic Acids Research (2023). DOI: 10.1093/nar/gkad734

Part 2

Self-healing of synthetic diamonds observed at room temperature

A team of chemists, materials scientists and aeronautical engineers, reports evidence of self-healing in a sample of synthetic diamond at room temperature.

In their study, reported in the journal Nature Materials, the group created samples of microwire diamonds, caused them to crack and then used an electron microscope to watch them heal. The editors at Nature have also published a Research briefing in the same journal issue outlining the work.

Ever since scientists discovered that diamonds could be made not only in the lab but also in industrial settings, work has been ongoing to find ways to make them less prone to cracking, which limits their use in a wide variety of applications. Prior research has shown that if diamonds are made using a hierarchical internal structure, they become less prone to cracking—but not enough to allow their use in desired applications. More recently, scientists have discovered that nanotwinned diamond composites (ntDC) have some degree of self-healing. But these observations were made with tests conducted at high pressure and temperatures. In this new effort, the research team wondered if similar types of self-healing might be possible at normal pressure and room temperature. To find out, the researchers created several ntDC nanotwinned samples using onion carbon compressed at very high temperatures. They then set up DSC and ntDC nanobeams using an ion beam technique. After mounting ntDC samples, the nanobeams were used to create cracks in the samples, the results of which were viewed using a scanning electron microscope. To ensure their results were reliable, the team conducted multiple fracture tests.

The research team observed self-healing in the ntDC samples. Testing showed the healed samples had a tensile strength of 34%. In studying the healed samples, the researchers found the presence of sp² and sp³-hybridized carbon atoms on opposite sides of cracks, which they describe as osteoblasts; these allowed for healing as they bonded with one another. The team also conducted simulations of what they observed and found that such interactions triggered C-C re-bonding across gaps, allowing healing.

Keliang Qiu et al, Self-healing of fractured diamond, Nature Materials (2023). DOI: 10.1038/s41563-023-01656-4

Fractured diamond can heal itself at room temperature, Nature Materials (2023). DOI: 10.1038/s41563-023-01665-3

Nobel in medicine goes to two scientists whose work enabled creation of mRNA vaccines against COVID-19

Two scientists won the Nobel prize in medicine on Monday for discoveries that enabled the creation of mRNA vaccines against COVID-19 that were critical in slowing the pandemic—technology that's also being studied to fight cancer and other diseases.

Katalin Karikó and Drew Weissman were cited for contributing "to the unprecedented rate of vaccine development during one of the greatest threats to human health," according to the panel that awarded the prize in Stockholm.

The panel said the pair's "groundbreaking findings ... fundamentally changed our understanding of how mRNA interacts with our immune system."

Traditionally, making vaccines required growing viruses or pieces of viruses and then purifying them before next steps. The messenger RNA approach starts with a snippet of genetic code carrying instructions for making proteins. Pick the right virus protein to target, and the body turns into a mini vaccine factory.

But in early experiments with animals, simply injecting lab-grown mRNA triggered a reaction that usually destroyed it. Karikó and Weissman figured out a tiny modification to the building blocks of RNA that made it stealthy enough to slip past immune defenses.

mRNA   vaccine is a "game changer" in shutting down the coronavirus pandemic, crediting the shots with saving millions of lives.

The duo's pivotal mRNA research was combined with two other earlier scientific discoveries to create the COVID-19 vaccines.

www.nobelprize.org/prizes/medi … dvanced-information/

Separating molecules requires a lot of energy. A nanoporous, heat-resistant membrane could change that

Industry has long relied upon energy-intensive processes, such as distillation and crystallization, to separate molecules that ultimately serve as ingredients in medicine, chemicals and other products.

In recent decades, there has been a push to supplant these processes with membranes, which are potentially a lower-cost and eco-friendly alternative. Unfortunately, most membranes are made from polymers that degrade during use, making them impractical.

To solve this problem, a  research team has created a new, sturdier membrane that can withstand harsh environments—high temperatures, high pressure and complex chemical solvents—associated with industrial separation processes.

Made from an inorganic material called carbon-doped metal oxide, it is described in a study published Sept. 7 in Science.

Researchers have developed is a technique to easily fabricate defect-free, strong membranes that have rigid nanopores that can be precisely controlled to allow different-sized molecules to pass through.

To create the membrane, the research team took inspiration from two common, but unrelated, manufacturing techniques.

The first is molecular layer deposition, which involves layering thin films of materials and is most often associated with semiconductor production. The second technique is interfacial polymerization, which is a method of combining chemicals that is commonly used to create fuel cells, chemical sensors and other electronics.

Bratin Sengupta et al, Carbon-doped metal oxide interfacial nanofilms for ultrafast and precise separation of molecules, Science (2023). DOI: 10.1126/science.adh2404

 Scientists find microplastics  in clouds too!

Researchers  have confirmed microplastics are present in clouds, where they are likely affecting the climate in ways that aren't yet fully understood.

In a study published in Environmental Chemistry Letters, scientists climbed Mount Fuji and Mount Oyama in order to collect water from the mists that shroud their peaks, then applied advanced imaging techniques to the samples to determine their physical and chemical properties.

The team identified nine different types of polymers and one type of rubber in the airborne microplastics—ranging in size from 7.1 to 94.6 micrometers.

Each liter of cloud water contained between 6.7 to 13.9 pieces of the plastics.

What's more, "hydrophilic" or water-loving polymers were abundant, suggesting the particles play a significant role in rapid cloud formation and thus climate systems.

"If the issue of 'plastic air pollution' is not addressed proactively, climate change and ecological risks may become a reality, causing irreversible and serious environmental damage in the future," the researchers warned.

When microplastics reach the upper atmosphere and are exposed to ultraviolet radiation from sunlight, they degrade, contributing to greenhouse gasses.

Microplastics—defined as plastic particles under 5 millimeters—come from industrial effluent, textiles, synthetic car tires,  personal care productsand much more.

Yize Wang et al, Airborne hydrophilic microplastics in cloud water at high altitudes and their role in cloud formation, Environmental Chemistry Letters (2023). DOI: 10.1007/s10311-023-01626-x

The very first beat: How a heart starts to pulse

How muscles change during endurance training

Nobel Prize in physics for split-second glimpse of superfast spinning world of electrons

Three scientists won the Nobel Prize in physics on Tuesday for giving us the first split-second glimpse into the superfast world of spinning electrons, a field that could one day lead to better electronics or disease diagnoses.

The award went to French-Swedish physicist Anne L'Huillier, French scientist Pierre Agostini and Hungarian-born Ferenc Krausz for their work with the tiny part of each atom that races around the center and is fundamental to virtually everything: chemistry, physics, our bodies and our gadgets.

Electrons move so fast that they have been out of reach of human efforts to isolate them, but by looking at the tiniest fraction of a second possible, scientists now have a "blurry" glimpse of them and that opens up whole new sciences. 

The electrons are very fast, and the electrons are really the workforce in everywhere. Once you can control and understand electrons, you have taken a very big step forward.

The scientists, who worked separately, used ever-quicker laser pulses to catch the atomic action that happened at such dizzying speeds—one quintillionth of a second, known as an attosecond.

www.nobelprize.org/uploads/202 … physicsprize2023.pdf

Atmospheric microplastic transport predominantly derived from oceans, study finds

Microplastics in our natural environments are of increasing concern as these tiny particles (<5mm diameter) pollute ecosystems, posing issues to the well-being of animals and humans alike. There are two principal categories of microplastics: primary particles are manufactured for their size and originate from consumer products, such as the microbeads used in cosmetics, while secondary microplastics occur due to the breakdown of larger materials, such as plastic water bottles and matter from industrial waste.

This breakdown occurs due to ultraviolet radiation from the sun causing plastic to become brittle and thus susceptible to the erosive action of waves in particular to shear off flakes into the surrounding environment.

Their longevity during decomposition, taking upwards of 500 years to complete in a landfill, is a critical factor of their detrimental impact on habitats. Marine animals ingest microplastics suspended in the ocean, and microplastics mixed with the sand on our beaches is barely noticeable. Research has discovered microplastics in the smallest plankton all the way through to filter feeding giants of the sea—whales.

But it is not just the ocean that transports these tiny particles across the globe. Atmospheric wind regimes can carry microplastics vast distances, and their shape has a critical impact on airborne retention before deposition.

New research published in Nature Geoscience considers a theory-based model to determine the settling velocity (the point at which a particle stops being suspended in air and settles due to gravity) of microplastics of various sizes and shapes (up to 100μm long and down to 2μm wide), as compared to previous research that has assumed spherical microplastics. The effect of air turbulence on settling velocity was also factored to determine long distance transport.

 Shuolin Xiao et al, Long-distance atmospheric transport of microplastic fibres influenced by their shapes, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01264-6

Science trying to take the STING out of runaway inflammation

Cytokine storm: Everybody came to know about it during the covid-19 pandemic.  But once this dangerous form of infection-triggered runaway inflammation started claiming lives by the thousands, a legion of scientists jumped into the hunt for ways to calm these storms.

Now, a study led by immunobiology experts at Cincinnati Children's, offers important new details on how two elements of our body's immune system clash with each other to prompt a chain of reactions that can release deadly floods of cell-killing, organ-damaging cytokines. Details were published Oct. 3, 2023, in the journal Cell Reports.

These findings have implications for both autoimmunity as well as cancer. Researchers have discovered an independent cell signaling pathway that allows a type of immune cell called an effector memory T cell (T_em) to become a critical driver of innate cytokine storms.

With a pathway defined, next steps include confirming whether medications that target key points along the pathway can disrupt the inflammation cycle before it becomes uncontrollable.

Part 1

The chain reaction appears to start when T_em cells interact with dendritic cells, which serve as the immune system's primary detector of viral and bacterial invasions. These starburst shaped cells carry a large collection of receptors to detect various types of invaders. Once they encounter a harmful visitor, dendritic cells latch on and sound an alarm that instructs the rest of the immune system's machinery to begin producing T cells that are custom designed to eliminate that type of invader.

When the immune system wins the battle, most of the custom T cells stand down. But a few guards linger in the blood and other body tissues to be ready to "effect" a rapid response should the same type on infection occur again. Hence the name effector memory T cells.

However, the research team discovered that ongoing encounters with T_em cells, such as those occurring when people have autoimmunity or live in a state of chronic inflammation, actually cause DNA strands within dendritic cells to break. This, in turn, prompts a DNA repair pathway that rapidly generates large numbers of inflammatory cytokines, including IL-1b, IL-6 and IL-12.

This flood, or storm, of cytokines causes the tissue damage that occurs in autoinflammatory diseases including type 1 diabetes, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel diseases like Crohn's disease. For some people with these conditions, ongoing inflammation also increases their risk of developing cancer.

Scientists worked for the last 10 years to examine the genetic activity and cell-to-cell communications occurring behind this process. 

The team found a surprising clue when examining the transcriptional profile of dendritic cells following their interaction with T_em cells. Specifically, they detected upregulation of expression of Tmem173, which encodes for stimulator of interferon genes (STING). The STING pathway has been described in previous research as being important to detect viral infections. But when T_em cells harm dendritic cells, the STING pathway does not follow the same route that it typically does when directly responding to viral infections.

In this situation, STING teams up with the gene TRAF6 and the transcription factor NFkB to form an "axis" of activity that drives runaway production of innate inflammatory cytokines.

The researchers further reasoned that if they could prevent STING and TRAF6 from working together, they could cut off the inflammation chain reaction at an early stage. In mice gene-edited to lack the STING pathway, that's exactly what they found. When treated with a drug known to induce an intense T cell-mediated inflammatory response, these mice did not produce a flood of innate cytokines.

The mouse study involved a whole-body elimination of STING. Attempting the same in humans would not be advisable because STING is used by a number of cell types outside the immune system in necessary ways.

Part 2

The goal before the scientists now is  to develop a highly focused method or methods for blocking STING within targeted immune cells, without disrupting its other important functions. If they  can achieve that, they may have a powerful new tool for controlling hyper-inflammation.

Hannah Meibers et al, Effector Memory T cells induce innate inflammation by triggering DNA damage and a non-canonical STING pathway in dendritic cells, Cell Reports (2023). DOI: 10.1016/j.celrep.2023.113180. www.cell.com/cell-reports/full … 2211-1247(23)01192-0

Part 3

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Why does it get hot when you rub things together? Unraveling the mystery of dynamic friction at the atomic level

Friction, an everyday phenomenon, has perplexed scientists for centuries. Though extensively researched, our understanding remains fragmented, primarily due to the multifaceted interactions that span across varying scales. Achieving an accurate grasp of the precise contact conditions between objects has been a longstanding challenge, a feat recently made possible through advancements in scanning probe microscopy.

Yet, even with these technological breakthroughs, the intricacies of dynamic friction—the force needed to maintain the movement of a molecule—have remained elusive. While scientists can measure static friction by moving a single molecule on a surface, both the measurement and theoretical understanding of dynamic friction have yet to be fully unveiled. Now, writing in Physical Review Letters and Physical Review B, a collaborative team of scientists report their groundbreaking study that dives deep into this challenge. They meticulously examined the manipulation of a carbon monoxide (CO) molecule on a single-crystal copper surface using an atomic force microscope. Backed by ab initio calculations, their findings shed light on how the CO molecule positions change relative to the microscope tip and surface, as well as the relationship between the motion of the molecule induced by the tip, energy dissipation, and both static and dynamic friction. This research stands out for its unequivocal clarity on the friction process. Not only does it provide fresh insights into a long-studied phenomenon, but it also paves the way for future studies on energy dissipation relaxation processes.

Norio Okabayashi et al, Dynamic Friction Unraveled by Observing an Unexpected Intermediate State in Controlled Molecular Manipulation, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.148001

Norio Okabayashi et al, Energy dissipation of a carbon monoxide molecule manipulated using a metallic tip on copper surfaces, Physical Review B (2023). DOI: 10.1103/PhysRevB.108.165401

**

Research shows humans can inherit AI biases

New research by psychologists provides evidence that people can inherit artificial intelligence biases (systematic errors in AI outputs) in their decisions.

The astonishing results achieved by AI systems that can, for example, hold a conversation as a human does have given this technology an image of high reliability.

More and more professional fields are implementing AI-based tools to support the decision-making of specialists to minimize errors in their decisions. However, this technology is not without risks due to biases in AI results. We must consider that the data used to train AI models reflects past human decisions. If this data hides patterns of systematic errors, the AI algorithm will learn and reproduce these errors. Indeed, extensive evidence indicates that AI systems do inherit and amplify human biases.

The most relevant finding of this new research is that the opposite effect may also occur: that humans inherit AI biases. That is, not only would AI inherit its biases from human data, but people could also inherit those biases from AI, with the risk of getting trapped in a dangerous loop. 

The most significant finding of the research was that after interaction with the AI system, those volunteers continued to mimic its systematic error when they switched to performing the diagnosis task unaided. In other words, participants who were first assisted by the biased AI replicated its bias in a context without this support, thus showing an inherited bias. This effect was not observed for the participants in the control group, who performed the task unaided from the beginning.

These results show that biased information by an artificial intelligence model can have a perdurable negative impact on human decisions. The finding of an inheritance of AI bias effect points to the need for further psychological and multidisciplinary research on AI-human interaction.

Furthermore, evidence-based regulation is also needed to guarantee fair and ethical AI, considering not only the AI technical features but also the psychological aspects of the AI and human collaboration.

Lucía Vicente et al, Humans inherit artificial intelligence biases, Scientific Reports (2023). DOI: 10.1038/s41598-023-42384-8

When fire & ice combine

Nobel Prize in chemistry for work on quantum dots, used in electronics and medical imaging

Three scientists won the Nobel Prize in chemistry Wednesday for their work on quantum dots—tiny particles just a few nanometers in diameter that can release very bright colored light and whose applications in everyday life include electronics and medical imaging.

Moungi Bawendi of MIT, Louis Brus of Columbia University, and Alexei Ekimov of Nanocrystals Technology Inc., were honored for their work with the tiny particles that "have unique properties and now spread their light from television screens and LED lamps," according to the Royal Swedish Academy of Sciences, which announced the award in Stockholm.

Quantum dots are tiny inorganic particles that glow a range of colors from red to blue when exposed to light. The color they emit depends upon the size of the particle.

Scientists can engineer the dots from materials that include gold to graphene to cadmium, and create their color by controlling their size. The tiniest particles, in which electrons are most tightly confined, emit blue light. Slightly larger particles, in which electrons bounce around a longer wavelength, emit red light.

What is anaphylaxis?

Maybe volcanoes doomed the dinosaurs

A machine-learning algorithm suggests that volcanic activity, rather than an asteroid,.... The algorithm simulated 300,000 scenarios of different amounts of volcanic gases until it found one that matched data from fossils. The gases would have started to cause dinosaur-dooming climate chaos long before the asteroid impact. “You can actually recreate the environmental conditions that could cause a dinosaur extinction solely by volcanism, as if the asteroid weren’t there,” says computational geologist and study co-author Alexander Cox. “But of course, we can't discount the fact that the asteroid definitely didn't cheer up the dinosaurs.”

https://www.science.org/doi/10.1126/science.adh3875

 How Amazonian forest degradation and monsoon circulation are interlinked

A pair of concerned researchers, has developed a computer model that shows linkages between forest degradation in the Amazon River basin and monsoon circulation.

That research suggested that if deforestation continues in the Amazon River basin, it could lead to a tipping point at which a certain degree of change can cause permanent changes to an ecosystem. In the case of the Amazon, the change would be from rainforest to a drier, savanna-like climate.

Over the course of many years, many studies have been conducted to understand how the characteristics of the Amazon River basin work together to maintain such a large rainforest. Such studies have shown that regional water cycling along with moisture exaltation from the plants, together with sunlight and even dust blown over from Africa, all contribute to the unique ecosystem, the largest rainforest in the world. Such work has also suggested that disruptions to parts of the system, such as cutting down trees, could result in major changes to the ecosystem. And if such changes were to occur, other studies have suggested the region would change from a rainforest to one that featured a vast savanna-like climate. Such a possible change is of major concern to climate scientists because the rainforest produces a lot of the Earth's oxygen. Additionally, destruction of the trees would result in the release of carbon they sequester, likely into the atmosphere, contributing further to climate change.

In this new effort, the researchers attempted to create a model that ties together degradation of the rainforest and monsoon circulation to show how and why a tipping point might be reached. To create their nonlinear dynamical model, the pair used data from other models that have been built over the past 40 years to simulate conditions in the rainforest. They also added weather data for the same period, including rainfall amounts, wind speeds and direction, and degree of evapotranspiration. They then modeled the rainforest in its original state to serve as a starting point. Next, they tweaked parameters to see the effects on the entire system. The model showed that cutting down trees at current rates in the Amazon region would indeed lead to a tipping point. They conclude that ecosystems with a feedback loop, such as the Amazon River basin, are particularly sensitive to change.

Nils Bochow et al, The South American monsoon approaches a critical transition in response to deforestation, Science Advances (2023). DOI: 10.1126/sciadv.add9973

New research may make future design of nanotechnology safer with fewer side effects

A new study, published in Nature Nanotechnology, may offer a strategy that mitigates negative side effects associated with intravenous injection of nanoparticles commonly used in medicine.

Nanotechnology's main advantage over conventional medical treatments is its ability to more precisely target tissues, such as cancer cells targeted by chemotherapy. However, when nanoparticles are injected, they can activate part of the immune system called complement. 

Complement is a group of proteins in the immune system that recognize and neutralize bacteria and viruses, including nanoparticles which are foreign to the body. As a result, nanoparticles are attacked by immune cells triggering side effects that include shortness of breath, elevated heart rate, fever, hypotension, and, in rare cases, anaphylactic shock.

The activation of the immune system after injection of nanoparticles can be challenging to understand and prevent. This new research is one step closer to providing a better understanding and a solution for people to receive the benefits of nanoparticles without side effects.

The researchers say while some progress has been made in mitigating adverse reactions through slow infusion and premedication with steroids and antihistamines, a significant number of people still experience reactions.

The goal is to prevent, avoid and mitigate adverse reactions and immune activation. 

Part 1

Specifically, this study focuses on an interesting group of complement inhibitors (called "regulators"). The research showed promising results.

Researchers  observed that the regulators being studied effectively inhibited complement activation by nanoparticles in human serum in vitro and animal models. Specifically, when injected at very low doses, the regulators completely and safely blocked activation of complement by nanoparticles in the animal models used. According to the authors, this is significant because when nanoparticles activate complement, the resulting immune response can not only cause an adverse reaction but it can also reduce the efficacy of nanomedicines.

This research also provides a better understanding of why and how complement regulators could help the body respond more favorably to nanoparticles. The study team observed that of the trillions of nanoparticles entering the blood in a standard injection, only a small fraction activated complement. Complement regulators worked as soon as nanoparticles started activating complement, thereby promptly mitigating immune activation.

These results suggest we have an exciting opportunity to explore how to further optimize the use of regulators with nanoparticles, with the goal of improving the efficacy and tolerability of multiple nanotechnology-based therapeutics and vaccines.

 The next step is to test the complement inhibitors with multiple nano particles and in difference disease models to fully understand the potential of this approach with the ultimate goal to apply the research in a clinical setting.

Inhibition of Acute Complement Responses Toward Bolus-Injected Nanoparticles by Targeted, Short-Circulating Regulatory Proteins, Nature Nanotechnology (2023). DOI: 10.1038/s41565-023-01514-z. www.nature.com/articles/s41565-023-01514-z

Part 2

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Iron atoms discovered on the move in Earth's solid inner core

The iron atoms that make up the Earth's solid inner core are tightly jammed together by astronomically high pressures—the highest on the planet.

But even here, there's space for wiggle room, researchers have found.

A study led by The University of Texas at Austin and collaborators in China found that certain groupings of iron atoms in the Earth's inner core are able to move about rapidly, changing their places in a split second while maintaining the underlying metallic structure of the iron—a type of movement known as "collective motion" that's akin to dinner guests changing seats at a table.

The results, which were informed by laboratory experiments and theoretical models, indicate that atoms in the inner core move around much more than previously thought.

The results could help explain numerous intriguing properties of the inner core that have long vexed scientists, as well as help shed light on the role the inner core plays in powering Earth's geodynamo—the elusive process that generates the planet's magnetic field.

Scientists think that iron atoms in the inner core are arranged in a repeating hexagonal configuration. According to Lin, most computer models portraying the lattice dynamics of iron in the inner core show only a small number of atoms—usually fewer than a hundred. But using an AI algorithm, the researchers were able to significantly beef up the atomic environment, creating a "supercell" of about 30,000 atoms to more reliably predict iron's properties.

At this supercell scale, the scientists observed groups of atoms moving about, changing places while still maintaining the overall hexagonal structure.

The researchers said that the atomic movement could explain why seismic measurements of the inner core show an environment that's much softer and malleable than would be expected at such pressures.

Youjun Zhang et al, Collective motion in hcp-Fe at Earth's inner core conditions, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2309952120

Scientists discover arginine drives metabolic reprogramming to promote tumor growth in liver cancer

Cancer cells are chameleons. They completely change their metabolism to grow continuously. University of Basel scientists have discovered that high levels of the amino acid arginine drive metabolic reprogramming to promote tumor growth. This study suggests new avenues to improve liver cancer treatment.

The liver is a vital organ with many important functions in the body. It metabolizes nutrients, stores energy, regulates the blood sugar level, and plays a crucial role in detoxifying and removing harmful components and drugs. Liver cancer is one of the world's most lethal types of cancer. Conditions that cause liver cancer include obesity, excessive alcohol consumption and hepatitis C infection. Early diagnosis and appropriate therapeutic strategies are crucial for improving treatments in liver cancer.

In the past decade, scientists have made much progress in understanding the multiple facets of cancer. Historically, it has long been viewed as a disorder in cell proliferation. However, there is growing evidence that cancer is a metabolic disease. In other words, cancer arises when cells rewire their metabolism to allow uncontrolled cell proliferation. How do cells change their metabolism and how does this change in turn lead to tumorigenicity? With their new study in Cell, researchers have discovered a key driver of metabolic rewiring in liver cancer cells.

Healthy liver cells gradually change their behavior when turning into cancer cells. They reprogram their metabolism to grow as fast as possible, for example, they consume much more glucose than normal cells and they enhance the uptake of nutrients.

The most important thing they found is  elevated levels of arginine, although cancer cells produce less or none of this amino acid. The tumour cells accumulate high levels of arginine by increasing its uptake and suppressing its consumption.

Part 1

Furthermore, they found that the high levels of arginine are necessary for tumor development, independently of the amino acid's role in protein synthesis. This then begged the question: How does arginine lead to tumorigenicity?

At high concentrations, arginine binds to a specific factor, which triggers metabolic reprogramming and promotes tumour growth by regulating the expression of metabolic genes. As a consequence, tumour cells revert back to an undifferentiated embryonic cell state, in which they can divide indefinitely. Interestingly, tumour cells also benefit in another way from increasing the uptake of arginine.

Our immune cells depend on arginine to function properly. Therefore, depleting arginine in the tumour environment helps the tumour cells escape the immune system.

What do these findings mean for cancer therapy? The scientists propose to target the specific arginine-binding factor rather than depleting arginine.

Furthermore, metabolic changes such as increased arginine levels may serve as biomarkers for detecting cancer at an early stage, which is crucial for successful cancer treatment and patient survival.

 Arginine reprograms metabolism in liver cancer via RBM39, Cell (2023). DOI: 10.1016/j.cell.2023.09.011. www.cell.com/cell/fulltext/S0092-8674(23)01032-2

Part 2

How male mosquitoes compensate for having only one X chromosome

The research group has discovered the master regulator responsible for balancing the expression of X chromosome genes between males and females in the malaria mosquito.

This discovery helps scientists to better understand the evolution of the epigenetic mechanisms responsible for equalizing gene expression between the sexes. The findings may contribute to the development of new ways to prevent the spread of malaria. 

Just like humans, the sex of a mosquito is determined by the sex chromosomes: females have two X chromosomes (XX), while males have an X and a Y chromosome (XY). This can be problematic, as males have only half the number of X chromosome genes as females, and hence would have only half the amount of proteins from the X chromosome. To compensate for this, there must be a way to increase the expression of X chromosome genes in males.

The researchers discovered that the protein SOA (sex chromosome activation) is the key regulator that balances X chromosome gene expression in male mosquitoes. They found that SOA works by binding to X chromosome genes and increasing their expression, but only in males. Female mosquitoes, on the other hand, only produce a small amount of very short, non-functional SOA.

Balancing gene expression on sex chromosomes is essential for development in some species. However, others do not have such a mechanism at all. It is now discovered that in mosquitoes, balancing X chromosome expression by SOA is not necessary for development, but it does give males a head start.

This is an important clue as to how the mechanisms that balance gene expression on sex chromosomes may have evolved in the first place.

Agata Izabela Kalita et al, The sex-specific factor SOA controls dosage compensation in Anopheles mosquitos, Nature (2023). DOI: 10.1038/s41586-023-06641-0

How do our brains tell us when something goes wrong?

Whether improperly closing a door or shanking a kick in soccer, our brains tell us when we've made a mistake because these sounds differ from what we expect to hear. While it's long been established that our neurons spot these errors, it has been unclear whether there are brain cells that have only one job—to signal when a sound is unexpected or "off."

A team of neuroscientists has now identified a class of neurons—what it calls "prediction-error neurons"—that are not responsive to sounds in general, but only respond when sounds violate expectations, thereby sending a message that a mistake has been made.

Brains are remarkable at detecting what's happening in the world, but they are even better at telling you whether what happened was expected or not. It 's found that there are specific neurons in the brain that don't tell you what happened, but instead tell you what went wrong. Neurons like these might be vital in learning how to speak or how to play a musical instrument. Both of those behaviors involve lots of trial and error, lots of mistakes, and lots of learning from mistakes

Nicholas J. Audette et al, Stimulus-specific prediction error neurons in mouse auditory cortex, The Journal of Neuroscience (2023). DOI: 10.1523/JNEUROSCI.0512-23.2023

Unique voice prints in parrots could help birds be recognized in a flock, no matter what they say

Parrots are exceptional talkers. They can learn new sounds during their entire lives, amassing an almost unlimited vocal repertoire. At the same time, parrots produce calls so they can be individually recognized by members of their flock—raising the question of how their calls can be very variable while also uniquely identifiable.

A study on monk parakeets might have the answer: individuals have a unique tone of voice, known as a voice print, similar to that in humans. This finding in a wild parrot raises the possibility that a voice print might also be present in other vocally flexible species, such as dolphins and bats.

It makes sense for monk parakeets to have an underlying voice print. It's an elegant solution for a bird that dynamically changes its calls but still needs to be known in a very noisy flock.

Humans have complex and flexible vocal repertoires, but we can still recognize each other by voice alone. This is because humans have a voice print: our vocal tract leaves a unique signature in the tone of our voice across everything that we say.

Other social animals also use vocal cues to be recognized. In birds, bats, and dolphins, for example, individuals have a unique "signature call" that makes them identifiable to members of the group. But signature calls encode identity in only one call type. To date, almost no evidence exists for animals having unique signatures that underlie all calls made by an individual. In other words, almost no animals are known to have a voice print.

Like humans, parrots use their tongue and mouth to modulate calls, meaning that their grunts and shrieks sound much more human than a songbird's clean whistle.

Also, like humans, parrots live in large groups with fluid membership. There could be tens of birds vocalizing at the same time. They need a way of keeping track of which individual is making what sound.

Part 1

Armed with shotgun microphones, researchers recorded the calls of hundreds of individuals, collecting over 5000 vocalizations in total, making it the largest study of individually-marked wild parrots to date. Importantly, they re-recorded the same individuals over two years, which revealed how stable the calls were over time.

They then used a set of models to detect how recognizable individuals were within each of the five main call types given by this species. Surprisingly, they found high variability in the so-called "contact call" that birds use to broadcast their identity. This overturned a long-held assumption that contact calls contain a stable individual signal—and suggested that the parakeets are using something else for individual recognition.
To test if voice prints were at play, scientists turned to a machine learning model widely used in human voice recognition, which detects the identity of the speaker using the timber of their voice. They trained the model to recognize calls of individual parrots that were classed as "tonal" in sound.
Once the model was trained on an individual, they then tested to see if the model could detect the same individual from a different set of calls that were classed as "growling" in sound. The model was able to do this three times better than expected by chance, providing evidence that monk parakeets have a voice print, which could allow individuals to recognize each other no matter what they say.

The researchers, however,  caution that the evidence is still preliminary. Before we can speak of a true voice print, we need to confirm that the model can repeat this result when it is trained with more data from more individuals, and that birds can also recognize this timbre in the vocalizations.

Simeon Smeele et al, Evidence for vocal signatures and voice-prints in a wild parrot, Royal Society Open Science (2023). DOI: 10.1098/rsos.230835. royalsocietypublishing.org/doi/10.1098/rsos.230835

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Part 2

Common Plastic Additive Linked to Autism And ADHD

The number of kids being diagnosed with autism spectrum disorder ( ASD) and attention deficit hyperactivity disorder ( ADHD) has risen sharply in recent decades, and a new study points to the common plastic additive bisphenol A (BPA) as a potential reason why. BPA is used in a lot of plastics and plastic production processes, and can also be found inside food and drink cans. However, previous research has also linked it to health issues involving hormone disruption, including breast cancer and infertility.

In this new study, researchers from Rowan University and Rutgers University in the US looked at three groups of children: 66 with autism, 46 with ADHD, and 37 neurotypical kids. In particular, they analyzed the process of glucuronidation, a chemical process the body uses to clear out toxins within the blood through urine.
The research found that kids with ASD and ADHD couldn't clear out BPA and another similar compound called Diethylhexyl Phthalate (DEHP) with as much efficiency as other kids, potentially leading to longer exposure to their toxic effects.

"Detoxification of these two plasticizers is compromised in children with ASD and ADHD," write the researchers in their published paper. "Consequently, their tissues are more exposed to these two plasticizers."

It was only in the case of BPA that the difference was statistically significant though: the efficiency was reduced by about 11 percent for kids with ASD and 17 percent for kids with ADHD, compared with the control group of children.
Part 1

The researchers think that gene mutations in certain individuals means that BPA can't be cleared as well as it needs to be, which means the substance sticks around in the body. That potentially could cause damage in terms of neuron development and operation.

Conditions like ASD and ADHD are thought to be brought on by a combination of genetic and environmental influences, and this new study brings together both of them. However, it's only part of the story – not every child with a neurodevelopmental disorder had problems flushing out BPA, so there are other factors at play, too.

Work is continuing to identify how exactly ASD and ADHD take hold in the body – whether it's in utero before birth for example, or later on in life – as the data isn't enough to show whether BPA exposure causes either disorder.

"There is an extensive body of epidemiological evidence for a relationship between neurodevelopmental disorders and environmental pollutants such as plasticizers," write the researchers.

"How important plasticizer originated neurodevelopmental disorder is in the overall occurrence of these disorders is not known, but it must account for a significant proportion or would not have been so easy to detect in a metabolic study of moderate size such as this study."

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0...

Part 2

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Digital watermark protections can be easily bypassed

Perhaps the most chilling aspect of AI is its capacity to generate deepfake images.

But recent developments portend a more unsettling trend as digital fakery turns malicious. Not only celebrities and politicians, ordinary citizens are targeted, too. People's faces are appearing in images on social media without their consent. 

Major digital media companies—OpenAI, Alphabet, Amazon, DeepMind—have promised to develop tools to combat disinformation. One key approach is the use of watermarking on AI-generated content.

A paper published Sept. 29 on the preprint server arXiv raises troubling news about the ability to curb such digital abuse.

Researchers ran tests demonstrating easy run-arounds of protective watermarks.

We don't have any reliable watermarking at this point because the researchers broke them all!

The team used a process called diffusion purification, which applies Gaussian noise to a watermark and then removes it. It leaves a distorted watermark that can bypass detection algorithms. The rest of the image is only minimally altered.

They further successfully demonstrated that bad actors with access to black-box watermarking algorithms could foist fake photos with markings that trick detectors into believing they are legitimate.

Better algorithms will certainly come along. As has been the case with viral attacks, the bad guys will always be working to break whatever defenses the good guys come up with, and the cat-and-mouse game will continue.

Mehrdad Saberi et al, Robustness of AI-Image Detectors: Fundamental Limits and Practical Attacks, arXiv (2023). DOI: 10.48550/arxiv.2310.00076

How synthesized plankton molecules inhibit cancer proteins

Researchers have discovered how to harness the toxic power of plankton to manufacture anti-cancer molecules.

In a paper, "Synthesis of portimines reveals the basis of their anti-cancer activity," published in Nature, the team details the steps taken in synthesizing marine toxins, portimine A and portimine B, enabling in-depth investigations into their properties

Dinoflagellate-derived cyclic imine toxins, specifically portimine A and portimine B, are of interest due to their potential anti-cancer therapeutic properties. Previous research has shown the effects of cyclic imine toxins on cancer cells, but the molecular mechanisms underlying the cause of the anti-cancer activity were unknown. Access to these toxins in large quantities is currently hard to come by as the only known producer is a type of tiny marine plankton, Vulcanodinium rugosum. To test the toxin's activity, the researchers first needed to innovate a way to synthesize large enough quantities to work with.

The synthesis began with constructing a minimally-decorated carbon skeleton devoid of most oxygen atoms. The idea was to leverage a macrocycle's innate reactivity to install the correct oxygenation pattern and stereochemistry.

Strategic ring-chain tautomerization events were employed to facilitate the synthesis using ring-closing alkyne metathesis to construct the 14-membered macrocycle in the portimines' skeleton. The innovation represents a scalable and concise synthesis of portimines. With the desired molecules created, the next step was to see how they interacted with cancer cells.

Part 1

The team tested interactions across a broad panel of 20 human and mouse cancer cell lines, ranging from Jurkat leukemia to metastatic human fibrosarcoma cells, triple-negative breast cancer and glioblastoma brain-tumor-initiating cell lines. Consistent potent cytotoxic activity was observed across the entire panel of cancer cell lines that were evaluated with portimine A. The fully synthetic portimine B was found to be substantially less effective.

Portimine A was identified as a potent inducer of apoptosis in various cancer cell lines, including MC38 cells, a colorectal carcinoma testing model. The apoptosis caused by portimine A had minimal effects on non-cancerous cells and low toxicity in mice.
Specifically, portimine A was found to target the 60S ribosomal export protein NMD3, blocking polysome formation and inhibiting protein translation and was observed to be an effective agent for suppressing tumor growth in vivo.

The exposure time to portimine A was limited by its half-life of around 30 minutes. The short duration still resulted in a significant reduction in tumor growth, indicating a very potent activity and potential therapeutic uses in the future.

Junchen Tang et al, Synthesis of portimines reveals the basis of their anti-cancer activity, Nature (2023). DOI: 10.1038/s41586-023-06535-1

The chemical synthesis and anti-cancer properties of portimines, Nature (2023). DOI: 10.1038/d41586-023-02788-y

Part 2

Study challenges the rules of evolutionary biology

Charles Darwin said that evolution was constantly happening, causing animals to adapt for survival. But many of his contemporaries disagreed. If evolution is always causing things to change, they asked, then how is it that two fossils from the same species, found in the same location, can look identical despite being 50 million years apart in age?

Everything changed in the past 40 years, when an explosion of evolutionary studies proved that evolution can and does occur rapidly—even from one generation to the next. Evolutionary biologists were thrilled, but the findings reinforced the same paradox: If evolution can happen so fast, then why do most species on Earth continue to appear the same for many millions of years?

This is known as the paradox of stasis and researchers set out to investigate it. 

  They conducted a long-term study in a community of lizards, measuring how evolution unfolds in the wild across multiple species. In doing so, he may have found the answer to one of evolution's greatest challenges.

The research was published as the cover story in the Proceedings of the National Academy of Sciences.

Scientists call this a paradox because it doesn't seem to make any sense. The most common explanation is that natural selection  is working to stabilize a species' appearance, with the assumption that an average form will help them survive the best. The problem is, when people do field studies, they almost never find that this kind of 'stabilizing' selection actually exists

Part 1

Scientists set up a field study with four different species of Anolis lizards (anoles) on a small island at the Fairchild Tropical Botanic Gardens in Coral Gables, Florida. They measured natural selection in all four lizard species over five consecutive time periods by catching and monitoring the survival of every lizard on the island.

The researchers searched day and night for lizards. Using long fishing poles with tiny lassos at their tips, they gently captured them by their strong necks, placed them in coolers, and documented the exact branch or stump where they found each lizard.

Back in the lab, they measured the lizards' heads, legs, feet, weight, and even the stickiness of their toes. After assigning an identifying number to each lizard and marking them with a tiny tag under the skin, the team released the lizards to the same branches where they'd found them. They went out in the following days and weeks to catch the rest of them.

Every six months for three years, the researchers started the process over again. Catching the same lizards, taking measurements, releasing them, and making notes of which lizards survived and which didn't.

For a very long time, evolutionary biologists have tried to figure out what was behind this paradox of stasis idea," the scientists said. "What this study shows is that the answer may not be particularly complicated—we just had to conduct a study in the wild for a long enough time to figure it out."

Stroud, James T. et al, Fluctuating selection maintains distinct species phenotypes in an ecological community in the wild, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2222071120. doi.org/10.1073/pnas.2222071120

Part 3

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Firefighting Fungi
Underneath every mushroom is a sprawling, branching network of rootlike structures called a mycelium. Now researchers have successfully grown these networks into Pop Tart–size sheets that could act as a fire retardant in building materials. Mycelium contains a lot of carbon. When exposed to fire, the sheet briefly burns, releasing water and carbon dioxide into the air, before petering out and leaving behind a black layer of carbon.

Why this is so cool: Unlike asbestos, which is still sometimes added to building materials as a fire retardant, mycelium does not shed noxious compounds when exposed to fire. Mycelium could replace the fire-retardant foam that insulates many commercial buildings, which can produce carbon monoxide and other toxic products when it combusts. Mycelium is also a biological material, and any waste it leaves behind is compostable.

What the experts say: “If the product reaches the end of its life, you can just chuck that mycelium in your garden,” says Everson Kandare an engineer at RMIT University in Melbourne, Australia. “Just toss it in the green beans.”

Remnant of cell division could be responsible for spreading cancer

Once thought to be the trash can of the cell, a little bubble of cellular stuff called the midbody remnant is actually packing working genetic material with the power to change the fate of other cells—including turning them into cancer.

When one cell divides into two, a process called mitosis, the result is not just the two daughter cells.

One cell divides into three things: two cells and one midbody remnant, a new signaling organelle. The midbody is full of genetic information, RNA, that doesn't have much to do with cell division at all, but likely functions in cell communication.

Researchers  analyzed the contents of midbodies—which form between the daughter cells during division—and tracked the interactions of the midbody remnants set free after cell division. Their results point to the midbody as a vehicle for the spread of cancer throughout the body.

What the researchers found inside midbodies was RNA—which is a kind of working copy of DNA used to produce the proteins that make things happen in cells—and the cellular machinery necessary to turn that RNA into proteins. The RNA in midbodies tends to be blueprints not for the cell division process but for proteins involved in activities that steer a cell's purpose, including pluripotency (the ability to develop into any of the body's many different types of cells) and oncogenesis (the formation of cancerous tumours).

A midbody remnant is very small. It's a micron in size, a millionth of a meter. But it's got everything it needs to sustain that working information from the dividing cell. And it can drift away from the site of mitosis, get into your bloodstream and land on another cell far away.

Part 1

Many midbody remnants are reabsorbed by one of the daughter cells that shed them, but those that touch down on a distant surface, like a lunar lander, may instead be absorbed by a third cell. If that cell swallows the midbody, it may mistakenly begin using the enclosed RNA as if it were its own blueprints.

Previous research showed that cancer cells are more likely than stem cells to have ingested a midbody and its potentially fate-altering cargo. Stem cells, which give rise to new cells and are valuable for their pluripotency, spit a lot of midbodies back out, perhaps to maintain their pluripotency.

Future research may be able to harness the power of midbody RNA to deliver drugs to cancer cells or to keep them from dividing.

The researchers identified a gene, called Arc, that is key to loading the midbody and midbody remnant with RNA. Taken up long ago from an ancient virus, Arc also plays a role in the way brain cells make memories.

Sungjin Park et al, The mammalian midbody and midbody remnant are assembly sites for RNA and localized translation, Developmental Cell (2023). DOI: 10.1016/j.devcel.2023.07.009

Part 2

Vacuum cleaner-effect in fungi can hold nanoplastics at bay

Researchers have investigated the effect of tiny polystyrene particles on bacteria and fungi. While these nanoplastics reduced both bacterial and fungal growth, the fungus actually managed to "clean up" their surroundings, thereby easing the effect of the plastics. 

Nanoplastics have been proven to induce toxicity in diverse organisms, yet very little is known how this new pollutant is affecting the soil ecosystem. To study these nanoparticles of polystyrene, the researchers used microfluidic chips, a growth system that allowed them to observe interactions of single cells with the plastics under the microscope.

At the highest nanoplastics concentration, the fungi caught most of the tiny plastics present in their vicinity, in a process that  the researchers labeled the 'vacuum cleaner effect.' Overall, they found that nanoplastics can cause a direct negative effect on the soil microbes. This highlights the need for further studies that can explain how the microbial stress response might affect soil functions.

The nanoplastic particles clung to the surface of the fungal branches in such a way that the surroundings were almost nanoplastic-free. The fungus cleaned up its surroundings under high concentrations, and could then grow better again. Although the results of the study were confirmed for many conditions, the researchers point out that it might be species dependent.

This serves as a reminder to reduce our plastic waste and the pollution of soils. Finding fungi that can specifically collect nanoplastics from the soil solution may help other organisms to sustain the pollution better, and perhaps attract bacteria that can break down plastics. The fungal 'vacuum cleaner' is not an easy fix for the problem, but can give a little hope for the future.

Paola M. Mafla-Endara et al, Exposure to polystyrene nanoplastics reduces bacterial and fungal biomass in microfabricated soil models, Science of The Total Environment (2023). DOI: 10.1016/j.scitotenv.2023.166503

Models suggest interlinking rivers in India to meet water demand may adversely impact monsoon rainfall amounts

A team of civil engineers and meteorologists at the Indian Institute of Technology, working with colleagues from the Indian Institute of Tropical Meteorology and the University of Hyderabad, has found, via modeling, that a plan to interlink rivers in India to capture rain runoff could inadvertently have a negative impact on the amount and location of monsoon rainfall.

In their study, published in the journal Nature Communications, the group used a variety of modeling techniques to test the possibility of unintended changes to weather patterns in India as interlinking projects are undertaken.

Officials in India have a clear problem on their hands—their country has a population of 1.4 billion people, the highest of any country in the world. And it is still growing. Such growth is presenting a host of problems, including how to feed so many people, sustain economic growth and manage water. This last problem has become dire—for India to feed its people, it must grow more food and that will require more water. But water availability is decreasing. To meet the demand, scientists and government officials have proposed and instigated a plan that entails digging canals between rivers to interlink them, with the idea of capturing more rainfall. Instead of allowing most of its rainfall to run off into rivers and then to the sea, the country plans to divert some of that water into other rivers that can be shunted into drier areas, where it can be used for irrigation. But doing so, the researchers on this new effort insist, could have unintended and perhaps disastrous side effects.

Part 1

Prior research has shown that exchange of material such as aerosols into the atmosphere can lead to a land-atmospheric feedback system, resulting in cooling of temperatures in a region, and subsequent changes in rainfall amounts. Likewise, irrigation efforts have been found to instigate land-atmosphere feedback as water from such systems evaporates into the atmosphere. Such systems have been found to have an impact on local hydrological cycles, and in some cases, can impact monsoon rains. These findings convinced the team on this new effort to take a closer look at the possible impact of interlinking rivers.

To estimate possible impacts, the team used causal delineation techniques along with general climate models that have been modified to focus specifically on India and its weather, and also a reanalysis of datasets built from land-atmosphere feedback systems that already exist in India.

The researchers found that land-atmosphere feedbacks from interlinked rivers could generate causal pathways between river basins in India—as one example, they found incidences of decreased rainfall in September (during monsoon season) by up to 12% in parts of the country that are already experiencing water shortages. They also found evidence of some areas experiencing more dryness during El Niño years. They conclude that more study is required before approving new river linking efforts.

Tejasvi Chauhan et al, River interlinking alters land-atmosphere feedback and changes the Indian summer monsoon, Nature Communications (2023). DOI: 10.1038/s41467-023-41668-x

Part 2

Why eyeballing four is easy but five is hard

Our brains use one mechanism to size up four or fewer items, and a different one f... — which is why doing the latter is so much harder. The brain contains specialized neurons that fire when we see a specific number of objects: some fire primarily when presented with one dot on a screen, for example. Brain scans of 17 people revealed that the neurons specializing in numbers of four or less responded very specifically and selectively to their preferred number. Neurons that specialize in five through nine responded strongly not only to their preferred number, but also to numbers immediately adjacent to it.

https://www.nature.com/articles/s41562-023-01709-3.epdf?sharing_tok...

Copycat nutrient leaves pancreatic tumors starving

A study by scientists suggests an entirely new approach to treat pancreatic cancer. The research shows that feeding tumors a copycat of an important nutrient starves them of the fuel they need to survive and grow. The method, described in the journal Nature Cancer, has been used in early clinical trials for lung cancer. However, the unique properties of pancreatic cancer may make the strategy an even stronger candidate in the pancreas.

Pancreatic cancer relies on the nutrient glutamine much more than other cancers, so therapies that can interfere with tumors' ability to access glutamine could be highly effective.

Pancreatic cancer is relatively rare, accounting for only 3% of all cancers. However, it has one of the lowest survival rates among cancers: most people only live three to six months after being diagnosed with this disease.

One of the challenges of treating pancreatic cancer has to do with the physical properties of the tumors themselves.

Pancreatic tumors tend to be packed in dense connective tissue that keeps them encapsulated from the rest of the body and cuts off their supply of oxygen. As a consequence, these cancers develop unique metabolic properties compared to other tumors, and this is something we may be able to exploit with new treatments.

Part 1

One of the metabolic quirks of pancreatic cancer is that it relies heavily on glutamine to produce energy for growth and survival. In the past, scientists have tried to block access to glutamine to slow the growth of pancreatic tumors, but this is easier said than done.

The new method relies on a molecule called DON that has structural similarities to glutamine but can't actually be used as a nutrient source. By studying mice, the research team found that DON significantly slowed pancreatic tumour growth and stopped the tumors from spreading.

Although DON was able to stop pancreatic tumors from using glutamine, pancreatic cancer cells can use other nutrients to grow in glutamine's absence. To combat this effect, the researchers combined DON with an existing cancer treatment that blocks the metabolism of asparagine, another important nutrient. The combined treatment had a synergistic effect, helping prevent the spread of pancreatic tumors to other distant organs, such as the liver and lungs.

This could be a game changer for pancreatic cancer, and a lot of the preclinical work needed to rationalize it and is already happening.

Maria Victoria Recouvreux et al, Glutamine mimicry suppresses tumor progression through asparagine metabolism in pancreatic ductal adenocarcinoma, Nature Cancer (2023). DOI: 10.1038/s43018-023-00649-1

Part 2

Evidence that albatrosses use infrasound to navigate long journeys

A new study  provides the first evidence that wandering albatrosses, one of the widest-ranging seabirds, may use infrasound to help them navigate long and featureless foraging trips covering thousands of miles.

Researchers show that albatrosses  orientate towards areas of "loud" microbarom infrasound when flying on long distance foraging trips. The paper published on this work is titled "Albatross movement suggests sensitivity to infrasound cues at sea."

Infrasound is a form of low-frequency sound that is inaudible to humans but is ubiquitous in the marine environment. Microbaroms are a type of infrasound associated with colliding ocean waves. Such wavy areas are also associated with strong winds, which albatrosses depend on to help them fly efficiently. The researchers used GPS trackers to determine the flight paths of 89 wandering albatrosses breeding in the Crozet Islands archipelago, Southern Ocean, over the course of their foraging trips to sea, which can last up to a month. They then compared these flight paths to modeled acoustic maps that the team had developed to represent the distribution of microbarom infrasound.

This revealed that wandering albatrosses orientate towards areas of "loud" microbarom infrasound when departing on bouts of directed flight, suggesting that they may perceive and respond to microbarom infrasound propagated over long distances.

 Natasha Gillies et al, Albatross movement suggests sensitivity to infrasound cues at sea, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2218679120

How plant-derived nutrients can affect the gut and brain

Can plant-derived nutrients alter gut bacteria to affect brain function? Scientists investigated this question in a study of overweight adults.

Their findings, published in the journal Gut, suggest that dietary fiber can exert influence on both the composition of gut bacteria and the reward signals in the brain and associated food decision-making. Prebiotics are used to foster the colonization of beneficial bacteria in the gut. These indigestible dietary fibers are found in plant-derived foods such as onions, leeks, artichokes, wheat, bananas, and in high concentrations in chicory root. They support gut health by promoting the growth and activity of beneficial gut bacteria. Researchers have now investigated whether certain prebiotics can also influence brain function by improving communication between the gut microbiome and the brain.

The study shows consumption of high-dose dietary prebiotics leads to a reduction in reward-related brain activation in response to high-calorie food stimuli. The results suggest a potential link between gut health and brain function, in this case food decision-making.

The findings, derived from advanced neuroimaging, next-generation sequencing of gut bacteria, and combined analyses of potential metabolic pathways, suggest that functional microbial changes may underlie the altered brain response towards high-caloric food cues. 

A better understanding of the underlying mechanisms between the microbiome, gut, and brain could help to develop new strategies that promote healthier eating habits in people at risk.

Evelyn Medawar et al, Prebiotic diet changes neural correlates of food decision-making in overweight adults: a randomised controlled within-subject cross-over trial, Gut (2023). DOI: 10.1136/gutjnl-2023-330365

Study shows live plant pathogens can travel on dust across oceans

Plant pathogens can hitch rides on dust and remain viable, with the potential for traveling across the planet to infect areas far afield, a finding with important implications for global food security and for predicting future outbreaks.

A study, "Assessing Long-distance Atmospheric Transport of Soilborne Plant Pathogens," published in the journal Environmental Research Letters, is the first to provide computer modeling evidence to support the idea that massive dust storms can transport viable pathogenic spores across continents and oceans.

The researchers found that viable spores of the deadly fungal plant pathogen Fusarium oxysporum (F. oxy) could be transported across the ocean and were likely deposited across a range of regions that include agricultural production zones.

The researchers found that this Godzilla ( a major dust storm) dust event could have potentially brought over 13,000 viable live spores, which is not a lot, but it's never been shown before, by any means, that viable soilborne pathogens could be transported trans-oceanically with dust.

Hannah Brodsky et al, Assessing long-distance atmospheric transport of soilborne plant pathogens, Environmental Research Letters (2023). DOI: 10.1088/1748-9326/acf50c

Сoconut shells can make concrete more durable

Scientists have found that concrete's compressive strength can be increased by 4.1% and its flexural strength by 3.4% by adding a small amount of coconut shell (only 5%). The material's performance increased by 6.1% compared to clear concrete. This effect is due to the fact that the cement paste—the bridge between all solid concrete particles—penetrates into the pores of the shell, firmly binding it with other components.

These results show that large amounts of coconut shell can be recycled without harm to the environment while improving the quality of building materials.

Sergey A. Stel'makh et al, Alteration of Structure and Characteristics of Concrete with Coconut Shell as a Substitution of a Part of Coarse Aggregate, Materials (2023). DOI: 10.3390/ma16124422

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Animals find humans scarier than lions

Human voices evoke more fear among animals living in the South African savanna than do snarls from lions. Researchers set up speakers near 21 water holes, which played one of several sounds when triggered by animal movement. When they heard humans, giraffes, leopards, elephants and 16 other species were twice as li... as when they heard growling lions, barking dogs or guns. The researchers suggest that recordings of human voices could be used to keep animals away from areas where a lot of poaching happens.

https://www.cell.com/current-biology/fulltext/S0960-9822(23)01169-7?utm_source=Nature+Briefing&utm_campaign=00a3d0b50b-briefing-dy-20231010&utm_medium=email&utm_term=0_c9dfd39373-00a3d0b50b-44672165