Using psychology  to cheat you: Casino Lights Could Be Warping Your Brain to Take Risks, Scientists Warn

Casino lighting could be nudging gamblers to be more reckless with their money, according to a new study, which found a link between blue-enriched light and riskier gambling behaviour.

The extra blue light emitted by casino decor and LED screens seems to trigger certain switches in our brains, making us less sensitive to financial losses compared to gains of equal magnitude, researchers found.

 As gambling addiction continues to be a growing global problem – with 1.2 percent of the world's population thought to have a gambling disorder – the study offers some important insight into how risky behaviors might be encouraged or discouraged.

Researchers found that light with more blue wavelengths in it, which is frequently emitted by LED screens and casino lighting, could subtly influence how people perceive losses and gains. This raises questions about the role of lighting in environments like casinos or online gambling platforms.

In the research conducted, on average, the participants were significantly less loss-averse under blue-enriched light. Men were more likely to take risky bets than women, which fits in with previous research into how gambling differs between the sexes.

The researchers think circadian photoreception, which is our non-visual response to light, is playing a part here. The level of blue spectrum light may be activating specific eye cells connected to brain regions in charge of decision-making, emotional regulation, and processing risk versus reward scenarios.

Under bright, blue-heavy light such as that seen in casino machines, the $100 loss didn't appear to feel as bad, so people were more willing to take the risk.

If you open up a gambling website or head into a casino, you'll notice there's a lot of blue light going on – the opposite of the warmer light that you'll often find in bedroom lighting and sleep aids such as lamps. Under light with more blue wavelengths, people may be less able to accurately judge risk and reward due to a decreased cognitive sensitivity to loss.

That raises some questions around ethics and responsibility, according to the researchers. While encouraging risk taking might be good for the gambling business, it's not good for the patrons spending their cash.

https://www.nature.com/articles/s41598-025-97370-z

 But what makes our brains decide a smell is bad?

A new study from UF Health researchers reveals the mechanisms behind how your brain decides you dislike—even loathe—a smell. The findings are published in the journal Molecular Psychiatry.

Odors are powerful at driving emotions, and it's long been thought that the sense of smell is just as powerful, if not more powerful, at driving an emotional response as a picture, a song or any other sensory stimulus.

Researchers wanted to answer these questions. 

They  started off with the amygdala, a brain region that curates your emotional responses to sensory stimuli. Although all our senses (sound, sight, taste, touch and smell) interact with this small part of your brain, the olfactory system takes a more direct route to it.

Smells evoke strong, emotional memories, but the brain's smell centers are more closely connected with emotional centers like the amygdala.

In the study, researchers looked at mice, who share neurochemical similarities with people. They can learn about odors and categorize them as good or bad. After observing their behavior and analyzing brain activity, the team found two genetically unique brain cell types that allow odors to be assigned into a bucket of good feelings or bad feelings.

Initially, the team expected that one cell type would generate a positive emotion to an odor, and another would generate a negative emotion. Instead, the brain's cellular organization gives the cells the capability of doing either.

It can make an odor positive or negative to you. And it all depends upon where that cell type projects in your brain and how it engages with structures in your brain.

 Sarah E. Sniffen et al, Directing negative emotional states through parallel genetically-distinct basolateral amygdala pathways to ventral striatum subregions, Molecular Psychiatry (2025). DOI: 10.1038/s41380-025-03075-0

Using ChatGPT to write essays may be eroding critical thinking skills

A team of neurologists and AI specialists at MIT's Media Lab has led a study looking into the brain impacts of large language model (LLM) use among people who engage with them for study or work. They report evidence that the use of LLMs may lead to an erosion of critical thinking skills. In their study, posted on the arXiv preprint server, the researchers asked groups of volunteers to write essays while connected to EEG monitors.

Researchers recruited 54 volunteers. The initial group was then split into three small groups, all of whom were asked to write a 20-minute esay on the topic of philanthropy—one group was asked to use ChatGPT for help, the second was asked to use Google Search, and the third "Brain-only" group was given no tools or resources at all. The participants remained in these same groups for three writing sessions.

Each of the volunteers was fitted with an EEG device to monitor brain activity, such as cognitive engagement and mental workload, while they wrote. The researchers also performed natural language processing analysis and interviewed participants after each session. Essays were scored by human teachers as well as an AI agent.

For these first three sessions, the EEG analysis showed clear differences in brain connectivity between the groups. The Brain-only group showed the strongest and most widespread brain network activity, the search engine group showed intermediate levels of engagement, and the ChatGPT group showed the weakest overall brain connectivity.

Out of the 54 volunteers, 18 also returned months later to complete a fourth session. Those who had used ChatGPT now went the Brain-only route, and vice versa. In this session, those who had originally used ChatGPT in the first three sessions showed weaker neural connectivity, while those from the previous Brain-only group demonstrated higher memory recall.

Overall, the interviews also revealed that volunteers who used the LLM felt less ownership over their essays compared to the other groups. ChatGPT users also struggled to recall or quote from their own essays shortly after writing them. Across all measures—brain activity, language analysis, and essay scoring—participants who relied on ChatGPT performed worse than the Brain-only group.

These findings highlight the potential educational impact of relying on LLMs for writing tasks. While they can provide immediate benefits, they run the risk of reduced learning outcomes over time and frequent use may hinder the development of critical thinking skills.

Nataliya Kosmyna et al, Your Brain on ChatGPT: Accumulation of Cognitive Debt when Using an AI Assistant for Essay Writing Task, arXiv (2025). DOI: 10.48550/arxiv.2506.08872

Researchers turn toxic ancient tomb fungus into anti-cancer drug

Researchers have turned a deadly fungus into a potent cancer-fighting compound. After isolating a new class of molecules from Aspergillus flavus, a toxic crop fungus linked to deaths in the excavations of ancient tombs, the researchers modified the chemicals and tested them against leukemia cells. The result? A promising cancer-killing compound that rivals FDA-approved drugs and opens up new frontiers in the discovery of more fungal medicines.

Aspergillus flavus, named for its yellow spores, has long been a microbial villain. After archaeologists opened King Tutankhamun's tomb in the 1920s, a series of untimely deaths among the excavation team fueled rumors of a pharaoh's curse. Decades later, doctors theorized that fungal spores,

 dormant for millennia, could have played a role.

In the 1970s, a dozen scientists entered the tomb of Casimir IV in Poland. Within weeks, 10 of them died. Later investigations revealed the tomb contained A. flavus, whose toxins can lead to lung infections, especially in people with compromised immune systems.

Now, that same fungus is the unlikely source of a promising new cancer therapy.

The therapy in question is a class of ribosomally synthesized and post-translationally modified peptides, or RiPPs, pronounced like the "rip" in a piece of fabric. The name refers to how the compound is produced—by the ribosome, a tiny cellular structure that makes proteins—and the fact that it is modified later, in this case, to enhance its cancer-killing properties.

Part1

While thousands of RiPPs have been identified in bacteria, only a handful have been found in fungi. In part, this is because past researchers misidentified fungal RiPPs as non-ribosomal peptides and had little understanding of how fungi created the molecules.

The synthesis of these compounds is complicated. But that's also what gives them this remarkable bioactivity.
To find more fungal RiPPs, the researchers first scanned a dozen strains of Aspergillus, which previous research suggested might contain more of the chemicals.

By comparing chemicals produced by these strains with known RiPP building blocks, the researchers identified A. flavus as a promising candidate for further study.

Genetic analysis pointed to a particular protein in A. flavus as a source of fungal RiPPs. When the researchers turned the genes that create that protein off, the chemical markers indicating the presence of RiPPs also disappeared.

This novel approach—combining metabolic and genetic information—not only pinpointed the source of fungal RiPPs in A. flavus, but could be used to find more fungal RiPPs in the future.After purifying four different RiPPs, the researchers found the molecules shared a unique structure of interlocking rings. The researchers named these molecules, which have never been previously described, after the fungus in which they were found: asperigimycins.

Even with no modification, when mixed with human cancer cells, asperigimycins demonstrated medical potential: two of the four variants had potent effects against leukemia cells.
Another variant, to which the researchers added a lipid, or fatty molecule, that is also found in the royal jelly that nourishes developing bees, performed as well as cytarabine and daunorubicin, two FDA-approved drugs that have been used for decades to treat leukemia.
Through further experimentation, the researchers found that asperigimycins likely disrupt the process of cell division. Cancer cells divide uncontrollably. These compounds block the formation of microtubules, which are essential for cell division.
Notably, the compounds had little to no effect on breast, liver or lung cancer cells—or a range of bacteria and fungi—suggesting that asperigimycins' disruptive effects are specific to certain types of cells, a critical feature for any future medication.
In addition to demonstrating the medical potential of asperigimycins, the researchers identified similar clusters of genes in other fungi, suggesting that more fungal RiPPS remain to be discovered.

 A class of benzofuranoindoline-bearing heptacyclic fungal RiPPs with anticancer activities, Nature Chemical Biology (2025). DOI: 10.1038/s41589-025-01946-9

Part 2

Earth's satellites at risk if asteroid smashes into moon

If a huge asteroid smashes into the moon in 2032, the gigantic explosion would send debris streaming toward Earth that would threaten satellites and create a spectacular meteor shower, according to researchers.

It was given the highest chance—3.1%—of hitting our home planet that scientists have ever measured for such a giant space rock.

Subsequent observations from telescopes definitively ruled out a direct hit on Earth.

However, the odds that it will crash into the moon have risen to 4.3%, according to data from the James Webb Space Telescope in May.

A new preprint study, which has not been peer-reviewed, is the first to estimate how such a collision could affect Earth.

It would be the largest asteroid to hit the moon in around 5,000 years. The impact would be comparable to a large nuclear explosion in terms of the amount of energy released.

Up to 100 million kilograms (220 million pounds) of material would shoot out from the moon's surface, according to a series of simulations run by the researchers.

If the asteroid hit the side of the moon facing Earth—which is roughly a 50% chance—up to 10% of this debris could be pulled in by Earth's gravity over the following days, they said.

 These meteors could be capable of destroying some satellites—and there are expected to be a lot more of those orbiting the planet by 2032.

A centimeter-sized rock traveling at tens of thousands of meters per second is a lot like a bullet.

In the days after the impact, there could be more than 1,000 times the normal number of meteors threatening Earth's satellites.

Meanwhile, those of us on the ground would be treated to a "spectacular" meteor shower lighting up the night sky, the study said.

But the current odds of a direct hit on the near side of the moon remain at just two percent

The asteroid is not expected to be visible again until 2028, so the world will have to wait to find out more.

If a direct hit is eventually found to be likely, humanity probably has enough time to plan a mission to spare the moon.

The preprint study, which was published on the arXiv database last week, has been submitted to the Astrophysical Journal Letters.

Upcycling plastic into painkillers: Microbes transform everyday waste into acetaminophen

Paracetamol is traditionally made from dwindling supplies of fossil fuels including crude oil. Thousands of tons of fossil fuels are used annually to power the factories that produce the painkiller, alongside other medicines and chemicals—making a significant contribution to climate change, experts say.

The breakthrough addresses the urgent need to recycle a widely used plastic known as polyethylene terephthalate (PET), which ultimately ends up in landfill or polluting oceans. The strong, lightweight plastic is used for water bottles and food packaging, and creates more than 350 million tons of waste annually, causing serious environmental damage worldwide.

PET recycling is possible, but existing processes create products that continue to contribute to plastic pollution worldwide, researchers say.

Published in Nature Chemistry, a team of scientists from the University of Edinburgh's Wallace Lab used genetically reprogrammed E. coli, a harmless bacterium, to transform a molecule derived from PET known as terephthalic acid into the active ingredient of paracetamol.

Researchers used a fermentation process, similar to the one used in brewing beer, to accelerate the conversion from industrial PET waste into paracetamol in less than 24 hours.

The new technique was carried out at room temperature and created virtually no carbon emissions, proving that paracetamol can be produced sustainably. Further development is needed before it can be produced at commercial levels, the research team says.

Part 1

Some 90% of the product made from reacting terephthalic acid with genetically reprogrammed E. coli was paracetamol.

Experts say this new approach demonstrates how traditional chemistry can work with engineering biology to create living microbial factories capable of producing sustainable chemicals while also reducing waste, greenhouse gas emissions and reliance on fossil fuels.

Nick W. Johnson et al, A biocompatible Lossen rearrangement in Escherichia coli, Nature Chemistry (2025). DOI: 10.1038/s41557-025-01845-5

Part 2

Antimicrobial resistance genes hitch rides on imported seafood

Colistin is a potent, last-resort antibiotic used only to treat people with dangerous, life-threatening bacterial infections that have developed resistance to other drugs. But it's not foolproof. Worldwide, resistance to colistin is spreading, further diminishing treatment options and putting infected people at higher risk.

Researchers have identified a way that colistin  resistance genes are spreading: imported seafood.

In a new study, microbiologists  have reported the first isolation of colistin-resistance genes in bacteria found in imported shrimp and scallops, purchased from eight food markets around Atlanta, GA.

 Some countries do not have strict regulations for using antibiotics in food animal production, so imported food can be a vehicle for transmission of resistance,

The researchers presented the findings in Los Angeles at ASM Microbe 2025, the annual meeting of the American Society for Microbiology. An accompanying paper will be published in the journal mSphere.

**

Scientists find new blood type in Guadeloupe woman

A French woman from the Caribbean island of Guadeloupe has been identified as the only known carrier of a new blood type, dubbed "Gwada negative," France's blood supply agency has announced.

The announcement was made 15 years after researchers received a blood sample from a patient who was undergoing routine tests ahead of surgery, the French Blood Establishment (EFS) said on Friday.

"The EFS has just discovered the 48th blood group system in the world!" the agency said in a statement on social network LinkedIn.

"This discovery was officially recognized in early June in Milan by the International Society of Blood Transfusion (ISBT)."

The scientific association had until now recognized 47 blood group systems.

Thierry Peyrard, a medical biologist at the EFS involved in the discovery, told AFP that a "very unusual" antibody was first found in the patient in 2011.

Scientists were finally able to unravel the mystery in 2019 thanks to "high-throughput DNA sequencing," which highlighted a genetic mutation

The patient, who was 54 at the time and lived in Paris, was undergoing routine tests before surgery when the unknown antibody was detected.

She is the only person in the world who is compatible with herself

The woman inherited the blood type from her father and mother, who each had the mutated gene.

Recycled plastics can affect hormone systems and metabolism, study shows

A single pellet of recycled plastic can contain over 80 different chemicals. A new study by researchers shows that recycled polyethylene plastic can leach chemicals into water, causing impacts on the hormone systems and lipid metabolism of zebrafish larvae.

The work is published in the Journal of Hazardous Materials.

The plastic pollution crisis has reached global levels, threatening both planetary and human health, and recycling is proposed as one of the solutions to the plastics pollution crisis. However, as plastics contain thousands of chemical additives and other substances that can be toxic, and these are almost never declared, hazardous chemicals can indiscriminately end up in recycled products.

In a new study, researchers bought plastic pellets recycled from polyethylene plastic from different parts of the world and let the pellets soak in water for 48 hours. After which, zebrafish larvae were exposed to the water for five days. The experimental results show increases in gene expression relating to lipid metabolism, adipogenesis, and endocrine regulation in the larvae.

These short leaching times and exposure times are yet another indicator of the risks that chemicals in plastics pose to living organisms. The impacts that we measured show that these exposures have the potential to change the physiology and health of the fish.

Previous research has shown similar effects to humans, including threats to reproductive health and obesity, from exposure to toxic chemicals in plastics. Some chemicals used as additives in plastics and substances that contaminate plastics are known to disturb hormones, with potential impacts on fertility, child development, links to certain cancers, and metabolic disorders including obesity and diabetes.

Azora König Kardgar et al, Effects of leachates from black recycled polyethylene plastics on mRNA expression of genes involved in adipogenesis and endocrine pathways in zebrafish embryos, Journal of Hazardous Materials (2025). DOI: 10.1016/j.jhazmat.2025.138946

Tomatoes in the Galápagos are quietly de-evolving

On the younger, black-rock islands of the Galápagos archipelago, wild-growing tomatoes are doing something peculiar. They're shedding millions of years of evolution, reverting to a more primitive genetic state that resurrects ancient chemical defenses.

These tomatoes, which descended from South American ancestors likely brought over by birds, have quietly started making a toxic molecular cocktail that hasn't been seen in millions of years, one that resembles compounds found in eggplant, not the modern tomato.

In a study published recently in Nature Communications, scientists at the University of California, Riverside, describe this unexpected development as a possible case of "reverse evolution," a term that tends to be controversial among evolutionary biologists.

That's because evolution isn't supposed to have a rewind button. It's generally viewed as a one-way march toward adaptation, not a circular path back to traits once lost. While organisms sometimes re-acquire features similar to those of their ancestors, doing so through the exact same genetic pathways is rare and difficult to prove.

However, reversal is what these tomato plants appear to be doing.

The key players in this chemical reversal are alkaloids. Tomatoes, potatoes, eggplants, and other nightshades all make these bitter molecules that act like built-in pesticides, deterring insect predators, fungi, and grazing animals.

While the Galápagos are famous as a place where animals have few predators, the same is not necessarily true for plants. Thus, the need to produce the alkaloids.

What makes these Galápagos tomatoes interesting isn't just that they make alkaloids, but that they're making the wrong ones, or at least, ones that haven't been seen in tomatoes since their early evolutionary days.

Part 1

The researchers analyzed more than 30 tomato samples collected from distinct geographic locations across the islands. They found that plants on eastern islands produced the same alkaloids found in modern cultivated tomatoes. But on western islands, the tomatoes were churning out a different version with the molecular fingerprint of eggplant relatives from millions of years ago.

That difference comes down to stereochemistry, or how atoms are arranged in three-dimensional space. Two molecules can contain exactly the same atoms but behave entirely differently depending on how those atoms are arranged.

To figure out how the tomatoes made the switch, the researchers examined the enzymes that assemble these alkaloid molecules. They discovered that changing just four amino acids in a single enzyme was enough to flip the molecule's structure from modern to ancestral.
They proved it by synthesizing the genes coding for these enzymes in the lab and inserting them into tobacco plants, which promptly began producing the old compounds.

The pattern wasn't random. It aligned with geography. Tomatoes on the eastern, older islands, which are more stable and biologically diverse, made modern alkaloids. Those on the younger, western islands where the landscape is more barren and the soil is less developed, had adopted the older chemistry.

The researchers suspect the environment on the newer islands may be driving the reversal. It could be that the ancestral molecule provides better defense in the harsher western conditions.
To verify the direction of the change, the team did a kind of evolutionary modeling that uses modern DNA to infer the traits of long-extinct ancestors. The tomatoes on the younger islands matched what those early ancestors likely produced.

Still, calling this "reverse evolution" is bold. While the reappearance of old traits has been documented in snakes, fish, and even bacteria, it's rarely this clear, or this chemically precise.
And this kind of change might not be limited to plants. If it can happen in tomatoes, it could theoretically happen in other species, too.
It wouldn't happen in a year or two, but over time, maybe, if environmental conditions change enough.
And if you change just a few amino acids, you can get a completely different molecule. That knowledge could help us engineer new medicines, design better pest resistance, or even make less toxic produce.

Adam Jozwiak et al, Enzymatic twists evolved stereo-divergent alkaloids in the Solanaceae family, Nature Communications (2025). DOI: 10.1038/s41467-025-59290-4

Part 2

500 bird species face extinction within the next century, researchers warn

Climate change and habitat loss could cause more than 500 bird species to go extinct in the next 100 years, researchers  have found.

Their study, published in Nature Ecology & Evolution, reveals this number is three times higher than all bird extinctions recorded since 1500 CE. The extinction of vulnerable birds such as the bare-necked umbrellabird, the helmeted hornbill, and the yellow-bellied sunbird-asity would greatly reduce the variety of bird shapes and sizes worldwide, harming ecosystems that depend on unique birds like these for vital functions.

The scientists found that even with complete protection from human-caused threats like habitat loss, hunting and climate change, about 250 bird species could still die out.

Many birds are already so threatened that reducing human impacts alone won't save them. These species need special recovery programs, like breeding projects and habitat restoration, to survive.

We face a bird extinction crisis unprecedented in modern times. We need immediate action to reduce human threats across habitats and targeted rescue programs for the most unique and endangered species, the researchers say.

The researchers examined nearly 10,000 bird species using data from the IUCN Red List. They predicted extinction risk based on the threats each species faces. The study found that large-bodied birds are more vulnerable to hunting and climate change, while birds with broad wings suffer more from habitat loss.

This research also identified which conservation actions will best preserve both the number of bird species and their ecological functions.

Stopping the destruction of habitats would save the most birds overall. However, reducing hunting and preventing accidental deaths would save birds with more unusual features, which are especially important for ecosystem health.

Threat reduction must be coupled with targeted recovery programmes to conserve global bird diversity, Nature Ecology & Evolution (2025). DOI: 10.1038/s41559-025-02746-z

New evidence map shows normal use of plastic packaging contaminates food with micro- and nanoplastics

In an article published in npj Science of Food, scientists led by the Food Packaging Forum show that the normal and intended use of plastic food packaging and other food contact articles (FCAs), such as opening a plastic bottle or chopping on a plastic cutting board, can contaminate foodstuffs with micro- and nanoplastics (MNPs).

The article describes how the authors systematically evaluated 103 previously published studies investigating plastic particles less than 10 mm in foodstuffs or food simulants that had been in contact with an FCA made partly or entirely of plastic.

Food contact articles are a relevant source of MNPs in foodstuffs; however, their contribution to human MNP exposure is underappreciated, the researchers say.

 Food contact articles as source of micro- and nanoplastics: a systematic evidence map, npj Science of Food (2025). DOI: 10.1038/s41538-025-00470-3

Why AI and humans see objects differently: Meaning versus visual features

While humans concentrate on the meaning of objects, artificial intelligence focuses on visual characteristics.

These dimensions represent various properties of objects, ranging from purely visual aspects, like 'round' or 'white,' to more semantic properties, like 'animal-related' or 'fire-related,' with many dimensions containing both visual and semantic elements.

 While humans primarily focus on dimensions related to meaning—what an object is and what we know about it—AI models rely more heavily on dimensions capturing visual properties, such as the object's shape or color. Researchers call this phenomenon 'visual bias' in AI.

"Even when AI appears to recognize objects just as humans do, it often uses fundamentally different strategies. This difference matters because it means that AI systems, despite behaving similarly to humans, might think and make decisions in entirely different ways, affecting how much we can trust them.

 Florian P. Mahner et al, Dimensions underlying the representational alignment of deep neural networks with humans, Nature Machine Intelligence (2025). DOI: 10.1038/s42256-025-01041-7

Scientists use gene editing to correct harmful mitochondrial mutations in human cells

In a step toward treating mitochondrial diseases, researchers  have successfully edited harmful mutations in mitochondrial DNA using a genetic tool known as a base editor. The results, published in the open-access journal PLOS Biology, offer new hope for people with rare genetic conditions.

Mitochondria have their own small set of DNA. Mutations in this mitochondrial DNA can lead to a wide range of maternally inherited diseases, cancer, and aging-related conditions. While the development of CRISPR technology has given scientists new ways to correct mutations in nuclear DNA, this system cannot effectively cross the mitochondrial membrane and reach mitochondrial DNA.

In the new study, the researchers used a tool called a base editor—specifically, a DdCBE (double-stranded DNA deaminase toxin A-derived cytosine bas editor). This tool allows scientists to change a single letter in the DNA code without cutting it, and it works on mitochondrial DNA.

The team showed that they could effectively generate and correct mitochondrial DNA mutations in multiple disease-linked cell types in the lab. First, they engineered liver cells to carry a mitochondrial mutation that impairs energy production. Then they showed they could fix a different mutation in skin cells taken from a patient with the mitochondrial disorder Gitelman-like syndrome, restoring key signs of healthy mitochondrial function.

To help move the therapy toward clinical use, the researchers also tested the efficacy of delivering the mitochondrial base editors in mRNA form, rather than as DNA, and within lipid nanoparticles for delivery.

They showed that these approaches are more efficient and less toxic to cells than older methods like DNA plasmids. Importantly, the edits were highly specific, with minimal off-target changes detected in nuclear DNA and multiple detected in mitochondrial DNA.

Joore IP, et al. Correction of pathogenic mitochondrial DNA in patient-derived disease models using mitochondrial base editors. PLOS Biology (2025). DOI: 10.1371/journal.pbio.3003207

Sharks freeze when you turn them upside down

The freeze response—called "tonic immobility"—can be a lifesaver. Possums famously "play dead" to avoid predators. So do rabbits, lizards, snakes, and even some insects.

But what happens when a shark does it?

Researchers explored this strange behavior in sharks, rays and their relatives. In this group, tonic immobility is triggered when the animal is turned upside down—it stops moving, its muscles relax, and it enters a trance-like state. Some scientists even use tonic immobility as a technique to safely handle certain shark species. 

The reasons behind tonic immobility remain murky—especially in the ocean. It is generally thought of as an anti-predator defense. 

Three main hypotheses try to explain this immobility in sharks:

Anti-predator strategy—"playing dead" to avoid being eaten

Reproductive role—some male sharks invert females during mating, so perhaps tonic immobility helps reduce struggle

Sensory overload response—a kind of shutdown during extreme stimulation.

But research results don't support any of these explanations.

 So, scientists offer a simpler explanation. Tonic immobility in sharks is likely an evolutionary relic.

Evolutionary analysis suggests tonic immobility is "plesiomorphic"—an ancestral trait that was likely present in ancient sharks, rays and chimeras. But as species evolved, many lost the behavior.

Whatever may be the reason if you want to handle the sharks safely, just turn them upside down!

 Joel H. Gayford et al, Tonic immobility in cartilaginous fishes (Chondrichthyes): function, evolutionary history, and future directions, Reviews in Fish Biology and Fisheries (2025). DOI: 10.1007/s11160-025-09958-3

Droughts can reduce the caloric value of flower nectar by up to 95%

A study indicates that projected droughts by the end of this century could reduce the caloric value of flower nectar by up to 95%. This would harm pollinators, such as bees, as well as plants that depend on cross-pollination to reproduce and bear fruit, such as zucchini (Cucurbita pepo). In a less drastic scenario with a 30% reduction in rainfall, the drop was 34%.

In terms of calories potentially lost in the nectar, this is equivalent to more than a ton of sugar per hectare, from 1,325 to 71 kilos. Without nectar to consume, the bees leave, the plants don't reproduce, and the farmers lose production.

The work showed that an increase in rainfall positively affected an increase in nectar calories by 74%. However, the researchers point out the problems of heavier rainfall events in a wider ecological context.

A high frequency and intensity of rainfall can have devastating consequences for plants, flower visitors such as birds and insects, and the maintenance of interactions between plants and pollinators.

For example, the researchers cite the decrease in pollinator activity during rainy periods. Heavy rains make it difficult for pollinators to fly and regulate their body temperature, so they require more energy to search for food. Additionally, increased erosion and loss of nutrients affect crops.

Maria Luisa P. Frigero et al, Extreme events induced by climate change alter nectar offer to pollinators in cross pollination-dependent crops, Scientific Reports (2025). DOI: 10.1038/s41598-025-94565-2

Scientists discover unknown organelle inside our cells

The discovery of an unknown organelle inside our cells could open the door to new treatments for devastating inherited diseases.

The organelle, a type of specialized structure, has been dubbed a "hemifusome" by its discoverers. This little organelle has a big job helping our cells sort, recycle and discard important cargo within themselves, the scientists say. The new discovery could help scientists better understand what goes wrong in genetic conditions that disrupt these essential housekeeping functions.

Researchers think the hemifusome helps manage how cells package and process material, and when this goes wrong, it may contribute to diseases that affect many systems in the body.

 Amirrasoul Tavakoli et al, Hemifusomes and interacting proteolipid nanodroplets mediate multi-vesicular body formation, Nature Communications (2025). DOI: 10.1038/s41467-025-59887-9

Scientists detect deep Earth pulses beneath Africa

Research led by Earth scientists has uncovered evidence of rhythmic surges of molten mantle rock rising from deep within the Earth beneath Africa. These pulses are gradually tearing the continent apart and forming a new ocean.

The findings, published in Nature Geoscience, reveal that the Afar region in Ethiopia is underlain by a plume of hot mantle that pulses upward like a beating heart.

The team's discovery reveals how the upward flow of hot material from the deep mantle is strongly influenced by the tectonic plates—the massive solid slabs of Earth's crust—that ride above it.

Over millions of years, as tectonic plates are pulled apart at rift zones like Afar, they stretch and thin—almost like soft plasticine—until they rupture. This rupturing marks the birth of a new ocean basin.

 Mantle upwelling at Afar triple junction shaped by overriding plate dynamics, Nature Geoscience (2025). DOI: 10.1038/s41561-025-01717-0

Why most cats prefer to sleep on their left side?

An international research team that analyzed several hundred YouTube videos of sleeping cats found that they prefer to sleep on their left side. The researchers see this bias as an evolutionary advantage because it favors hunting and escape behavior after waking up.

All animals are particularly vulnerable while sleeping. Cats sleep around 12 to 16 hours a day, preferably in elevated places where their predators can only access them from below.

Researchers analyzed 408 publicly available YouTube videos in which a single cat was clearly visible with its entire body sleeping on one side for at least 10 seconds.

Two-thirds of the videos showed cats sleeping on their left side.

The explanation: Cats that sleep on their left side perceive their surroundings upon awakening with their left visual field, which is processed in the right hemisphere of the brain. This hemisphere is specialized in spatial awareness, the processing of threats and the coordination of rapid escape movements. If a cat sleeps on its left shoulder and wakes up, visual information about predators or prey goes directly to the right hemisphere of the brain, which is best in processing them. "Sleeping on the left side can therefore be a survival strategy," the researchers conclude.

Sevim Isparta et al, Lateralized sleeping positions in domestic cats, Current Biology (2025). DOI: 10.1016/j.cub.2025.04.043

Nitrate in drinking water linked to preterm birth rates

Even low levels of nitrate—a common agricultural runoff and drinking water contaminant—are associated with increased risks of preterm birth and low birthweight babies, according to a study published in PLOS Water.

Nitrate is a naturally occurring compound increasingly found in inorganic fertilizers and, through runoff, in groundwater. When consumed by humans, nitrates can interfere with the blood's capacity to carry oxygen.

After controlling for maternal and paternal characteristics as well as seasonal variation, the study found that early prenatal exposure to greater than 0.1 mg/L nitrate—just 1% of the current EPA limit—was associated with an increase in preterm birth (Est.=+0.66%-points; C.I.=0.31, 1.01) and early prenatal exposure to greater than 5 mg/L nitrate was associated with an increased risk of low birth weight babies (Est.=+0.33%-points; C.I.=0.03, 0.63). There were no additional risks conferred by exposure to elevated levels of nitrate, above 10 mg/L.

PLOS Water (2025). DOI: 10.1371/journal.pwat.0000329

How diverse brain cells reach a decision together

Every decision begins invisibly. Long before someone acts, the brain is already hard at work gathering evidence, weighing options, and gradually committing to a choice. But even when faced with the same evidence, people can arrive at different outcomes, especially when the decision is difficult.

How the brain, made up of billions of specialized cells, makes these split-second decisions has largely been a mystery, though.

Now, new findings  shed light on how diverse brain cells come together to guide a unified decision. The researchers found that while individual neurons have perplexingly complex responses, their activity is shaped by a shared structure that ultimately guides the brain toward a unified choice.

Though each neuron had a different individual response, they all appeared to share the same underlying potential landscape.

Think of it like a group of skiers descending a mountain. Each prefers a slightly different path, but all are shaped by the same slope beneath them. Similarly, each neuron has its own preference and activity, but the group of cells collectively in the premotor cortex takes a coordinated journey and gradually settles into a stable state that represents the decision, say the researchers.

Tatiana Engel, The dynamics and geometry of choice in the premotor cortex, Nature (2025). DOI: 10.1038/s41586-025-09199-1. www.nature.com/articles/s41586-025-09199-1

Global study links severe bleeding after childbirth to increased risk of cardiovascular disease

Women who experience severe bleeding after giving birth face elevated risks to their cardiovascular health that can persist for up to 15 years—a new analysis of data from over 9.7 million women across Europe, North America and Asia shows.

The findings, which follow a review of research data, some of which date back to 1986, suggest that women who experience postpartum hemorrhage (PPH) have an increased risk to both cardiovascular conditions—such as heart failure, stroke, and ischemic heart disease—and thromboembolic events, such as blood clots.

Published in The Journal of Maternal-Fetal & Neonatal Medicine, the results reveal these cardiovascular conditions are 1.76 times more likely, while thromboembolic incidents are 2.10 times more likely.

While this increased risk is particularly acute in the first year after giving birth, it can persist for up to 15 years, especially among women with complications that lead to high blood pressure during pregnancy, such as preeclampsia.

PPH has long been seen as an emergency that ends once the bleeding stops. But these new findings show it may have lasting effects on a woman's heart health, even years after childbirth.

Postpartum hemorrhage and long-term cardiovascular disease risk: a comprehensive systematic review and meta-analysis, The Journal of Maternal-Fetal & Neonatal Medicine (2025). DOI: 10.1080/14767058.2025.2507103

Cold drinks may trigger irregular heartbeat in some people with atrial fibrillation (Afib)

It may sound strange, but for some people, cold drinks may be to blame for sudden episodes of atrial fibrillation (Afib), a common heart rhythm disorder.

A recent survey sheds light on this phenomenon, dubbed "cold drink heart" (CDH). Researchers found that a surprising number of people with Afib report cold beverages as a trigger for their irregular heartbeats. In fact, for half of the survey participants who identified cold ingestion as an Afib trigger, avoiding cold drinks and foods completely eliminated their episodes. Others found relief by modifying their habits, such as letting drinks warm up, skipping the straw, or avoiding gulping.

Why might a cold drink send your heart out of rhythm?

While the exact mechanism isn't fully understood, it's likely related to the vagus nerve, which plays a role in regulating heart rate. The sudden temperature change from a cold drink might stimulate this nerve, leading to changes in heart rhythm in susceptible individuals, say experts.

It's important to remember that not everyone with Afib will experience this trigger. However, if you notice a connection between cold drinks and your Afib episodes, it's worth discussing with your doctor. Simple lifestyle changes, like avoiding very cold beverages or letting them warm up, could make a significant difference.

This doesn't replace the need for medical evaluation and treatment for Afib. If you experience any symptoms like heart palpitations, shortness of breath, or dizziness, seek medical attention promptly.

The survey, published in the Journal of Cardiovascular Electrophysiology, is the first to systematically explore the link between cold drinks and Afib. While more research is needed, the findings suggest that for some, a simple change in drinking habits could be a key to managing their condition.

Daniel D. DiLena et al, Characterizing Patients With Cold Drink‐Triggered Atrial Fibrillation, Journal of Cardiovascular Electrophysiology (2025). DOI: 10.1111/jce.16753

Synthetic protein jams up diseased cells
A synthetic ‘killswitch’ protein, just 17 amino acids long, can jam droplet-like structures that coordinate key cellular processes such as cancer, viral replication, gene expression and more. The droplet-like structures have no membranes and help to organize proteins and RNA molecules so that they can perform specific tasks efficiently and precisely. The killswitch infiltrates the droplets and fixes them in place. In a pair of experiments, researchers found that the killswitch could reduce leukaemia cell proliferation in mice and also curtail the production of viral particles in infected cells.

https://www.nature.com/articles/s41586-025-09141-5?utm_source=Live+...

Tech giants' net zero goals verging on fantasy: Researchers

The credibility of climate pledges by the world's tech giants to rapidly become carbon neutral is fading fast as they devour more and more energy in the race to develop AI and build data centers, researchers warned this week.

Apple, Google and Meta said they would stop adding CO₂ into the atmosphere by 2030, while Amazon set that target for 2040.

Microsoft promised to be "net negative"—pulling CO₂ out of the air—by the end of this decade.

But those vows, made before the AI boom transformed the sector, are starting to look like a fantasy even as these companies have doubled down on them, according to independent analysts.

"The greenhouse gas emissions targets of tech companies appear to have lost their meaning", the researchers say.

Source: News agencies

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Exercise sends 'mechanical messages' to cells, unlocking new energy pathways

Scientists  have made a breakthrough in understanding how cells in our body respond to physical activity and exercise.

Researchers discovered a direct mechanical signal that travels from outside the cell into the energy-producing parts of the cell, which could change the way we think about exercise and its benefits.

Researchers found a protein production factory in the cell, the endoplasmic reticulum, can sense external mechanical forces, such as stretching or strain and transmit them deep into the cell.

The process helps regulate energy production in the cell and maintains tissue health.

Cells constantly experience physical forces, especially in load-bearing tissues such as tendon, muscle and lung. Researchers found that the endoplasmic reticulum plays a central role in converting these mechanical cues into metabolic responses, controlling how cells produce energy and prevent tissue damage.

They discovered that while moderate physical activity and exercise could enhance energy production in cells, excessive strain or injury could disrupt this process, leading to cellular damage.

 Ziming Chen et al, External strain on the plasma membrane is relayed to the endoplasmic reticulum by membrane contact sites and alters cellular energetics, Science Advances (2025). DOI: 10.1126/sciadv.ads6132

Study shows sleeping brain remains alert to harsh, urgent sounds

During sleep, the brain must achieve a delicate balance: disconnecting from sensory input to allow restorative functions, while remaining alert enough to wake if danger arises. How does it sort through external stimuli—particularly sounds—during sleep? Scientists have studied how the brain responds to so-called "rough" sounds, such as screams or alarms.

They discovered that these sounds are systematically processed, unlike other sounds, triggering specific brain waves. These results, published in the journal Scientific Reports, provide a better understanding of certain perceptual disorders, such as hyperacusis (hypersensitivity and/or intolerance to certain sounds), as well as the impact of repeated nighttime disturbances on brain function.

Roughness is an acoustic property characterized by rapid modulations of sound intensity, between 40 and 100 times per second. Unlike speech, where syllables occur at a rate between 4 and 8 Hz, rough sounds hit the auditory system at much higher frequencies, producing a shrill and often unpleasant sensation.

This quality—typical of audible alarms, human screams and infant cries—is precisely what makes them so effective: They automatically capture our attention to signal imminent danger. These sounds directly activate the amygdala, a brain region involved in emotional responses and attention.

In the research conducted, the roughness—regardless of whether the sound was high- or low-pitched—that activated the brain's alert systems. The research team also observed two key phenomena. First, rough sounds consistently triggered a brain response, unlike other types of sounds. Second, sound roughness correlated with an increase in sleep spindles. These are short bursts of brain activity elicited in response to a sensory, and potentially disturbing, stimulus during sleep.

Sound roughness is not commonly encountered in everyday environments. In both humans and animals, it's typically reserved for urgent, high-stakes communication.

 Guillaume Y. T. Legendre et al, Scream's roughness grants privileged access to the brain during sleep, Scientific Reports (2025). DOI: 10.1038/s41598-025-01560-8

Scientists 3D-print part of human femur as strong as real bone

A group of  doctors and scientists printed part of a human femur—the longest and strongest bone in the body—that mimics the strength, flexibility and overall mechanics of a real femur. The findings were published in 2024 in a study in the Journal of Orthopaedic Research.

Recreating bones and organs like the heart or blood vessels is an emerging field. 3D-printed organs are far from replicating the functionality of a flesh-and-blood organ. 3D-printed bones, however, are being leveraged to various degrees.

 In scientific studies assessing how different forces stress and contort bone, these skeletal replicas offer scientists and physicians an accessible alternative to what is typically used: cadaver bones.

The printed bones  have the same strength or maybe even better strength than the human femur.

The 3D-printed bone is made with a low-cost biodegradable polymer called polylactic acid. In total, the bone costs about $7 to make, which is much cheaper than making other synthetic bones or obtaining cadaver bones.

Robert C. Weinschenk et al, Three‐dimensional‐printed femoral diaphysis for biomechanical testing—Optimization and validation, Journal of Orthopaedic Research (2024). DOI: 10.1002/jor.25954

Plants, food and the environment also have microbiomes. For example, soil microbes help plants grow by cycling nutrients and fermented foods such as yogurt contain beneficial bacteria that support gut health. Environmental microbiomes, such as those in the Arctic permafrost, play vital roles in regulating climate by controlling greenhouse gas emissions.

Microbiomes are being threatened by human activities that disrupt their natural balance, according to research.

 In humans, the overuse of antibiotics, cesarean sections and formula feeding can reduce the diversity of gut microbes, leading to increased risks of allergies, autoimmune diseases and metabolic disorders. In food, the excessive use of preservatives and additives can harm beneficial microbes.

The microbiome is under big threat, a threat that is in many ways analogous to climate change. Human activities are depleting our microbiome, and there's lots of evidence of that.

For plants, unsustainable agricultural practices, such as heavy pesticide use, can destroy soil microbiomes essential for nutrient cycling and plant health. Environmental microbiomes are affected by pollution, climate change and habitat destruction, which can lead to the loss of microbes that regulate greenhouse gas emissions and maintain ecosystem stability.

The idea of the initiative is to support efforts to identify healthy microbes, store them and freeze them before they disappear.

It is a long term project  and maybe 100 years from now, having saved these microbes could prevent a major disaster.

 Safeguarding Earth's microbial heritage for future generations: focus on the Microbiota Vault Initiative, Nature Communications (2025). www.nature.com/articles/s41467-025-61008-5

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Scientists reveal how diverse cell types are produced in developing embryos

A team of scientists has uncovered a previously unknown mechanism that controls how genes are switched "on" and "off" during embryonic development. Their study sheds light on how diverse cell types are produced in developing embryos.

The research is published in Developmental Cell.

All cells contain the same DNA but must turn specific genes '"on" and "off"—a process known as gene expression—to create different body parts. The cells in your eyes and arms harbor the same genes but "express" them differently to become each body part.
The work focused on the gene Cdx2. The duration of Cdx2 expression helps to determine where and when a cell produces spinal cord progenitors. The researchers wanted to understand what processes control this brief window.

The team discovered a DNA element they termed an "attenuator," which reduces gene expression in a time and cell type-specific manner—unlike enhancers or silencers, other types of DNA elements that broadly switch genes on or off.

By altering this element, they could tune how long or how strongly Cdx2 was expressed, effectively acting like a "genetic dimmer switch." Disrupting the "switch" in mouse embryos also confirmed its essential role in shaping the developing body plan.

Part 1

This breakthrough paves the way towards programmable gene expression, offering the ability to precisely control gene activity in space and time. The findings not only deepen our understanding of developmental biology but may inform new therapeutic strategies targeting the non-coding genome.
Such approaches could one day enable treatments that selectively adjust gene expression in specific tissues, with implications for diseases caused by gene misregulation.

A dual enhancer-attenuator element ensures transient Cdx2 expression during mouse posterior body formation, Developmental Cell (2025). DOI: 10.1016/j.devcel.2025.06.006. www.cell.com/developmental-cel … 1534-5807(25)00361-2

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Individual neurons in amygdala and hippocampus encode visual features that help recognize faces

Humans are innately capable of recognizing other people they have seen before. This capability ultimately allows them to build meaningful social connections, develop their sense of identity, better cooperate with others, and identify individuals who could pose a risk to their safety.

Most studies  so far suggest that the identity of others is encoded by neurons in the amygdala and hippocampus, two brain regions known to support the processing of emotions and the encoding of memories, respectively.

Based on evidence collected in the past, researchers have concluded that neurons in these two brain regions respond in specific ways when we meet a person we are acquainted with, irrespective of visual features (i.e., how their face looks).

A recent paper published in Nature Human Behaviour, however, suggests that this might not be the case, and that individual neurons in the amygdala encode and represent facial features, ultimately supporting the identification of others.

Across four experiments (3,581 neurons from 19 neurosurgical patients over 111 sessions), researchers demonstrated a region-based feature code for faces, where neurons encode faces on the basis of shared visual features rather than associations of known concepts, contrary to prevailing views.

Feature neurons encode groups of faces regardless of their identity, broad semantic categories or familiarity; and the coding regions (that is, receptive fields) predict feature neurons' response to new face stimuli.

Together, these results reveal a new class of neurons that bridge perception-driven representation of facial features with mnemonic semantic representations, which may form the basis for declarative memory.

Runnan Cao et al, Feature-based encoding of face identity by single neurons in the human amygdala and hippocampus, Nature Human Behaviour (2025). DOI: 10.1038/s41562-025-02218-1.

AI is learning to lie, scheme, and threaten its creators

The world's most advanced AI models are exhibiting troubling new behaviors—lying, scheming, and even threatening their creators to achieve their goals.

In one particularly jarring example, under threat of being unplugged, Anthropic's latest creation Claude 4 lashed back by blackmailing an engineer and threatened to reveal an extramarital affair.

Meanwhile, ChatGPT-creator OpenAI's o1 tried to download itself onto external servers and denied it when caught red-handed.

These episodes highlight a sobering reality: more than two years after ChatGPT shook the world, AI researchers still don't fully understand how their own creations work.

Yet the race to deploy increasingly powerful models continues at breakneck speed.

This deceptive behavior appears linked to the emergence of "reasoning" models—AI systems that work through problems step-by-step rather than generating instant responses.

O1 was the first large model where developers saw this kind of behaviour.

These models sometimes simulate "alignment"—appearing to follow instructions while secretly pursuing different objectives.

For now, this deceptive behavior only emerges when researchers deliberately stress-test the models with extreme scenarios.

The concerning behavior goes far beyond typical AI "hallucinations" or simple mistakes.

Users report that models are "lying to them and making up evidence".This is not just hallucinations. There's a very strategic kind of deception.

But current regulations aren't designed for these new problems.

Source: News Agencies

https://techxplore.com/news/2025-06-ai-scheme-threaten-creators.htm...

Switching on a silent gene revives tissue regeneration in mice

Researchers recently discovered that switching on a single dormant gene enables mice to regenerate ear tissue.

Some vertebrates such as salamanders and fish can regenerate complex tissue structures with precision. A lost limb can be regrown, a damaged heart or eye can be repaired. Salamanders are so remarkable at reconstructing damaged tissues that even a spinal cord injury with severed neural motor connectivity can be restored.

Mammals occasionally showcase the ability to regenerate. Deer antlers and goat horns are examples of living tissue regeneration. Mice can regrow fingertips if they are lost. A healthy human liver can experience up to 70% loss of tissue and regrow to near full size within several weeks.

However, for the most part, mammals have seemingly replaced the ancient capacity for tissue regeneration with scarring, a trade-off that increases immediate survival of an injury by closing and sealing the wound.

Ear tissue punch regeneration has previously been studied in specific strains of Murphy Roths Large mice that have the ability to close 2-mm ear punches with scar-free regeneration. They can regenerate cartilage, dermis, epidermis, hair follicles, and even nerves in the ear tissue, and have shown some capacity to repair heart damage as well. Rabbits too have this ability to regenerate holes in ear tissue, suggesting that the capacity may have been shared by a common ancestor.

Rabbits and mice are related species that share a common ancestor around 90 million years ago which had previously diverged from the human primate ancestor around the same time. Millions of years of separate evolution have left the regeneration gene itself intact, but rewired its expression, extinguishing an ancestral regenerative response in most rodents that a few mice and the rabbit lineage still deploy.

Part 1

In the study, "Reactivation of mammalian regeneration by turning on an evolutionarily disabled genetic switch," published in Science, researchers conducted comparative genomic analyses of regenerative mammals, rabbits, goats, and African spiny mice, and nonregenerative mice and rats.

Analyzing ear pinna injury recovery in these mammals, researchers used single-cell RNA sequencing, spatial transcriptomic profiling, bulk RNA sequencing, ChIP-seq, ATAC-seq, and Micro-C to identify gene activity differences in wound-induced fibroblasts, specialized cells crucial to tissue regeneration.
Genetic analysis identified regulatory elements required for regeneration after injury that have become inactive in nonregenerative species. Reactivation of this genetic switch induced regeneration of damaged structures, and skipping the genetic mechanism by supplying the retinoic acid worked even better.

Weifeng Lin et al, Reactivation of mammalian regeneration by turning on an evolutionarily disabled genetic switch, Science (2025). DOI: 10.1126/science.adp0176

Part 2

Rerouted bile acid thwarts tumor spread in colorectal cancer mouse model

Research  has found that bile acid diversion in Roux-en-Y gastric bypass (RYGB) reduces colorectal tumor growth and metastasis independent of weight loss, potentially reshaping future cancer treatment approaches.

More than 2 billion adults worldwide are now overweight or obese, a condition marked by chronic low-grade inflammation and metabolic disruption that can promote tumor growth, increasing the risk of developing at least 15 types of cancer.

Previous research has focused on how losing weight with RYGB reshapes cancer outcomes, leaving unanswered questions about biological mechanisms behind RYGB's anticancer correlation.

In the study, "Metabolic surgery reduces CRC disease progression through circulating bile acid diversion," published in Science Translational Medicine, researchers developed a combined mouse model of obesity and colorectal cancer to determine whether bile acid diversion after gastric bypass surgery reduces tumorigenesis and metastasis independent of weight loss.

In the experiments conducted by researchers, mice that underwent Roux-en-Y gastric bypass developed primary colorectal tumors that were significantly smaller and exhibited almost no liver metastases compared with sham-operated controls. Even when researchers extended tumor development periods to allow increased tumor size, metastases remained disproportionately low in RYGB mice, suggesting that metabolic changes, rather than weight loss alone, drive this anticancer effect.

When bile acid diversion was achieved by cholecysto-intestinal shunt alone, similar suppression of tumor growth and metastasis occurred. Circulating bile acids in gastric bypass animals shifted toward reduced primary bile acids and elevated secondary bile acids, a pattern absent in diet-restricted controls.

Fecal microbiome composition remained largely unchanged after bile diversion, and transplantation of microbiota from treated mice into high-fat diet recipients did not confer anticancer effects.

Part 1

Analysis of the tumor microenvironment revealed no differences in immune cell populations between groups. In a cohort of patients with colorectal cancer, higher serum concentrations of primary bile acids correlated with shorter time to metastasis. This pinpointed dramatic alterations in bile acid circulation following RYGB surgery as the likely key factor inhibiting tumor progression and metastasis.

Further exploration revealed that gut microbiome alterations or immune system changes were not involved in this observed anticancer effect, leaving a reduced-primary/ elevated-secondary bile-acid profile as the only distinguishable change.
Researchers think that this altered bile acid metabolism of increased secondary bile acid and decreased primary bile acid contributes to reduced tumor growth and metastasis, although the precise mechanisms are still unknown.

Claudia Lässle et al, Metabolic surgery reduces CRC disease progression through circulating bile acid diversion, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.ads9705

Elizabeth R. M. Zunica et al, Bile diversion underlies Roux-en-Y antitumor benefits, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.adx3814

Part 2

Certain species of microbe found in the human gut can absorb PFAS

PFAS (perfluoroalkyl and polyfluoroalkyl substances) can't be avoided in the modern world. These man-made chemicals are in many everyday items, including waterproof clothing, non-stick pans, lipsticks and food packaging, used for their resistance to heat, water, oil and grease. But because they take thousands of years to break down, they are accumulating in large quantities in the environment—and in our bodies.

There are over 4,700 PFAS chemicals in widespread use. Some get cleared out of the body in our urine in a matter of days, but others with a longer molecular structure can hang around in the body for years.

PFAS have been linked with a range of health issues including decreased fertility, developmental delays in children, and a higher risk of certain cancers and cardiovascular diseases.

Scientists  have identified a family of bacterial species, found naturally in the human gut, that absorb various PFAS molecules from their surroundings. When nine of these bacterial species were introduced into the guts of mice to 'humanize' the mouse microbiome, the bacteria rapidly accumulated PFAS eaten by the mice, which were then excreted in feces.

Certain species of human gut bacteria have a remarkably high capacity to soak up PFAS from their environment at a range of concentrations, and store these in clumps inside their cells. Due to aggregation of PFAS in these clumps, the bacteria themselves seem protected from the toxic effects.

The researchers also found that as the mice were exposed to increasing levels of PFAS, the microbes worked harder, consistently removing the same percentage of the toxic chemicals. Within minutes of exposure, the bacterial species tested soaked up between 25% and 74% of the PFAS.

The results are the first evidence that our gut microbiome could play a helpful role in removing toxic PFAS chemicals from our body—although this has not yet been directly tested in humans.

The researchers plan to use their discovery to create probiotic dietary supplements that boost the levels of these helpful microbes in our gut, to protect against the toxic effects of PFAS.

The results are published in the journal Nature Microbiology.

 Human gut bacteria bioaccumulate per- and polyfluoroalkyl substances, Nature Microbiology (2025). DOI: 10.1038/s41564-025-02032-5

Biases shape how people mentally represent social ties in their community, families, relatives and social networks, study suggests.

Throughout the course of their lives, humans are known to build social ties with various other individuals in their community. Past neuroscience and psychology studies suggest that as humans form bonds with others, they also mentally represent them in their minds, creating internal maps that outline the relationships between different members of their community.

Researchers carried out a study aimed at better understanding how people mentally represent social networks, using data collected from residents of 82 villages.

Their findings, published in Nature Human Behaviour, uncovered some biases in people's mental representation of connections between others, especially between people who belong to the same family and close community groups.

People not only form social networks, they construct mental maps of them. 

The results of the analyses carried suggest that people's mental representations of the connections between people around them are flawed. Specifically, they found that people often overestimate the closeness of other people's connections, especially family ties.

Many individuals believed that family members spent more time with each other than they did, while friendships and non-family ties appeared to be more accurately represented in their internal "maps." Moreover, people's judgements about others' social ties appeared to be more accurate when these others shared their same religion or had similar levels of wealth. Interestingly, the researchers also found that middle-aged, well-educated and well-connected people internally represented the connections between others more accurately.

Overall, people inflate the number of connections in their networks and exhibit varying accuracy and bias, with implications for how people affect and are affected by the social world.

The findings gathered by this team of researchers shed new light on how people internally map ties within their community and on the biases that can reduce the accuracy of their mental representations. 

Eric Feltham et al, Cognitive representations of social networks in isolated villages, Nature Human Behaviour (2025). DOI: 10.1038/s41562-025-02221-6.

Animals living at higher elevations found to have decreased sense of smell

A recent study published in Current Biology has found that animals living at elevations of 1,000 meters and higher have a reduction in genes related to smell and a smaller olfactory bulb than similar low-altitude species.

The researchers screened the genomes of 27 different species of animals living in high-altitude environments, as well as their low-altitude relatives. A wide range of mammal types was studied, including monkeys, goats, llamas and guinea pigs. Both domesticated and wild mammals were included.

Scientists found a 23% reduction in genes related to smell and an average of an 18% size reduction of the olfactory bulb, a kind of smell processing center located in the brain. These evolutionary changes appear to be specific to smell. No changes were found in the genes related to pheromone and taste detection.

Environmental differences at high altitudes include thinner, drier and colder air, which can lead to difficulties in breathing, increased nasal congestion and hypoxia—low levels of oxygen in the body. These conditions also make it harder for scent molecules to travel—meaning there are fewer available scents for animals to detect in the air.

Although the exact mechanism is still unclear, the reduced sense of smell may be related to the reduction of available scents and to nasal inflammation, which causes additional difficulties in picking up scents. Over time, these issues may have led to mountain-dwelling animals evolving a worse sense of smell, but possibly compensating with better  other senses.

The study also compared the genomes of human communities at high and low altitudes. Researchers studied the genomes of Tibetans, who were estimated to have established their mountain-dwelling communities at altitudes above 3,000 meters sometime between 9,000 and 30,000 years ago. These were compared with the genomes of the low-altitude Han Chinese populations.

Interestingly, no olfactory changes were found in human populations. Researchers posit that this may be due to the continued mixing of lowland and highland populations, or because there may not have been enough generations for the genetic changes to occur yet.

Part 1

This research provides a novel twist on prior studies of the effects of high-altitude living. Prior studies have mostly focused on adaptation by gaining new functions or traits to cope with harsh environments, while this study shows that animals can also lose certain abilities. These understudied mechanisms of maladaptation and trait loss may have future implications for evolutionary biology and medicine.

 Allie M. Graham et al, Convergent reduction of olfactory genes and olfactory bulb size in mammalian species at altitude, Current Biology (2025). DOI: 10.1016/j.cub.2025.05.061

Part 2

Neurons duped into delivering mitochondria to cancer cells found fueling tumor spread

Researchers report that neurons can transfer mitochondria directly to cancer cells, enhancing their metastatic potential.

Oncologists have long suspected that tumors thrive partly by enlisting help from surrounding nerves. Pathologists studying cancer tissues have observed that tumors nestled among dense networks of nerves often grow faster and spread farther. Previous rodent and human studies demonstrated that cutting off this neural input slowed cancer growth.

Intercellular mitochondrial transfer is a recognized cellular rescue attempt where healthy donor cells revive compromised recipients by donating functional mitochondria. 

In the study, "Nerve-to-cancer transfer of mitochondria during cancer metastasis," published in Nature, researchers employed murine breast cancer models and advanced lineage-tracing reporters to test whether neurons confer metabolic assets to tumor cells via mitochondrial transfer.

Researchers performed chemical denervation by injecting botulinum neurotoxin A (BoNT/A) around breast tumors in mice. Denervation refers to the deliberate interruption of nerve supply to a tumor to chemically disable local nerve function.

The team then compared these denervated tumors to saline-injected controls using transcriptomic profiling, histopathology, and measurements of mitochondrial content.

Denervated tumors showed a marked reduction in mitochondrial load, downregulation of metabolic gene pathways (notably the tricarboxylic acid cycle), and significantly lower incidence of invasive lesions (from 55% in controls to 12% in denervated mice). These findings demonstrate that nerve inputs actively sustain tumor bioenergetics and promote progression.

part 1

Next, to test mitochondrial transfer from neurons to cancer cells, the team engineered neurons to express mitochondria tagged with fluorescent markers with a novel tracking system called MitoTRACER. The system allowed researchers to monitor cancer cells after mitochondrial transfer, enabling detailed tracing of their fate during disease progression.

Direct mitochondrial transfer was observed via tunneling nanotubes, initiated by neurons towards the cancer cells. Rho-zero cancer cells regained oxidative phosphorylation and uridine-independent growth after acquiring neuronal mitochondria, confirming functional rescue.

MitoTRACER revealed that recipient cancer cells displayed enhanced respiration, higher ATP, improved redox balance, and greater resistance to oxidative and mechanical stress.

In animal models, these labeled recipient cells were significantly enriched in metastases, especially in the brain and liver, indicating that neuronal mitochondria confer a selective advantage during dissemination.

Together, these two experimental arms show that nerves both sustain tumor energetics broadly and act as direct donors of functional mitochondria, a dual mechanism that promotes cancer survival and spread.
Denervation experiments established that disrupting nerve input deprives cancer cells of essential bioenergetic capacity, reducing their invasiveness. Cancer cells that had received neuronal mitochondria more readily survived metastatic stressors such as oxidative damage and mechanical shear forces, common hurdles faced during cancer dissemination.

Gregory Hoover et al, Nerve-to-cancer transfer of mitochondria during cancer metastasis, Nature (2025). DOI: 10.1038/s41586-025-09176-8

Part 2

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Psilocybin rewires brain circuits to boost fear extinction and behavioural flexibility in mice

Psilocybin, a psychedelic compound contained in some varieties of mushrooms, has recently been found to be promising for the treatment of some neuropsychiatric disorders, including depression, some anxiety disorders and post-traumatic stress disorder(PTSD). Some studies suggest that the consumption of this compound may be particularly advantageous for individuals who struggle to adapt their behavior in helpful ways when facing unexpected events or changes in their environment.

While a growing pool of research has been assessing the therapeutic benefits of psilocybin  the neural mechanisms through which it promotes long-lasting psychological changes remain poorly understood. If it does prompt greater behavioral flexibility in individuals diagnosed with some psychiatric disorders, the processes through which it does so are not yet clear.

Researchers  recently carried out a new study on mice, which was aimed at better understanding how psilocybin could increase adaptability and potentially ease symptoms of anxiety disorders or PTSD. Their findings, published in Nature Neuroscience, suggest that the compound prompts the reorganization of neural circuits in the retrosplenial cortex , a part of the brain located in the posterior region of the cerebral cortex (i.e., the outermost layer of the mammalian brain).

Researchers, in their experiments,   found that a single dose of psilocybin altered cortical ensemble turnover and oppositely modulated fear- and extinction-active neurons. Suppression of fear-active neurons and recruitment of extinction-active neurons predicted psilocybin-enhanced fear extinction.

These results suggested that psilocybin enhances behavioral flexibility by recruiting new neuronal populations and suppressing fear-active populations in the retrosplenial cortex.

Sophie A. Rogers et al, Psilocybin-enhanced fear extinction linked to bidirectional modulation of cortical ensembles, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-01964-9.

Engineered bacterial vesicles created to combat antimicrobial resistance

Bacteria are ubiquitous microscopic organisms capable of rapid growth. While beneficial strains like lactic acid bacteria (LAB) promote gut health and food preservation, pathogenic bacteria such as Escherichia coli and Staphylococcus aureus can cause severe infections. These harmful microbes produce toxins and enzymes that compromise health and, increasingly, show resistance to conventional antibiotics.

In recent years, scientists have explored alternative approaches to tackle pathogenic bacteria. Among them, endolysins—enzymes that degrade bacterial cell walls—have emerged as potent tools. These proteins, often derived from bacteriophages or engineered microbes, offer specificity in targeting pathogens. However, their widespread use is limited by challenges such as high production costs, instability during storage or circulation, and susceptibility to enzymatic degradation.

To address this research gap, researchers have turned their attention to extracellular vesicles (EVs)—membrane-bound nanoparticles released by cells that transport biologically active molecules like proteins or nucleic acids. They engineered EVs derived from LAB to carry pathogen-specific endolysins on their surface.

Their findings were published in the Chemical Engineering Journal on 15 May, 2025. The research outlines the discovery and application of a novel surface-displaying protein found on EVs from Lacticaseibacillus paracasei.

Jeongmin Lee et al, Surface-displaying protein from Lacticaseibacillus paracasei–derived extracellular vesicles: Identification and utilization in the fabrication of an endolysin-displaying platform against Staphylococcus aureus, Chemical Engineering Journal (2025). DOI: 10.1016/j.cej.2025.162196