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

**

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

Part 2

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

Part 2

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

Air pollution is linked to adverse birth outcomes in India

Prenatal exposure to ambient fine particulate matter and climatic factors, such as temperature and rainfall, are associated with adverse birth outcomes in India, according to a study published in PLOS Global Public Health 

Ambient air pollution poses a global threat to human health, with a disproportionate burden of its detrimental effects falling on those residing in low and middle-income countries. Referred to as the silent killer, ambient air pollution is among the top five risk factors for mortality in both males and females.

With a diameter of less than 2.5 microns, ambient fine particulate matter 2.5 (PM2.5), which primarily originates from the burning of fossil fuels and biomass, is considered the most harmful air pollutant. In the 2023 World Air Quality Report, India was ranked as the third-most polluted country out of 134 nations based on its average yearly PM2.5 levels.

Ambient air pollution has been associated with a range of pediatric morbidities, including adverse birth outcomes, asthma, cancer, and an increased risk of chronic diseases.

To address the knowledge gap, the researchers investigated the impact of ambient air pollution on adverse birth outcomes at the national level, focusing on  low birth weight and preterm birth, and used different geospatial models to highlight vulnerable areas. The analysis provided evidence of the association between in-utero exposure to PM2.5 and adverse birth outcomes by leveraging satellite data and large-scale survey data.

The individual-level analysis revealed that an increase in ambient PM2.5 is associated with a greater likelihood of low birth weight and preterm birth. Climatic factors such as rainfall and temperature were also linked to adverse birth outcomes. Children residing in the Northern districts of India appeared to be more susceptible to the adverse effects of ambient air pollution.

PLOS Global Public Health (2025). DOI: 10.1371/journal.pgph.0003798

Unlocking the mystery behind Barrett's esophagus

A research team has shed light on the process that drives Barrett's esophagus formation. This condition affects the lining of the esophagus—the tube that carries food from the mouth to the stomach—and increases the risk of developing esophageal adenocarcinoma, a serious and often deadly cancer.

The study, published in the Journal of Clinical Investigation, reveals that two important genes involved in guiding and maintaining the identity of the esophagus and intestine, SOX2 and CDX2, are altered in Barrett's esophagus. The findings not only deepen our understanding of how the disease develops but also open the door to new ways of identifying people at risk and potentially preventing the condition from progressing to cancer.

It is known that Barrett's esophagus usually develops after long-term exposure to acid and bile reflux, which transforms the cells of the lining of the esophagus into cells that look more like those in the stomach and the intestine.

The esophagus, which is not normally exposed to acid, adapts to acid reflux by becoming more like the stomach or the intestine, organs that are used to an acidic or bile-rich environment.

Eliminating acid reflux with medication does not heal Barrett's esophagus; the cells do not revert to their typical esophagus characteristics.

Under the microscope, Barrett's lesions show increased cell proliferation and a disorganized tissue with stomach-like and intestine-like cells where only esophageal cells should be.

To gain insight into what drives the transformation of esophageal cells into stomach and intestinal cells, the team investigated transcription factors SOX2 and CDX2, which are proteins that regulate the identity of esophageal and intestinal cells, respectively.

The findings support the idea that Barrett's esophagus may arise from the acid- and bile-triggered reprogramming of normal esophageal cells by altering the balance of SOX2 and CDX2. This new understanding could help scientists find strategies to intervene earlier in the disease process as well as develop new ways to provide an early diagnosis.

Ramon U. Jin et al, SOX2 regulates foregut squamous epithelial homeostasis and is lost during Barrett's esophagus development, Journal of Clinical Investigation (2025). DOI: 10.1172/JCI190374

Food contact articles as source of micro- and nanoplastics

At the frontier between two lives—the evolutionary origins of pregnancy

An international research team  has uncovered new insights into how specialized cell types and communication networks at the interface between mother and fetus evolved over millions of years. These discoveries shed light on one of nature's most remarkable innovations—the ability to sustain a successful pregnancy. The findings have just been published in Nature Ecology & Evolution.

Pregnancy that lasts long enough to support full fetal development is a hallmark evolutionary breakthrough of placental mammals—a group that includes humans. At the center of this is the fetal-maternal interface: the site in the womb where a baby's placenta meets the mother's uterus, and where two genetically distinct organisms—mother and fetus—are in intimate contact and constant interaction.

This interface has to strike a delicate balance: intimate enough to exchange nutrients and signals, but protected enough to prevent the maternal immune system from rejecting the genetically "foreign" fetus.

To uncover the origins and mechanisms behind this intricate structure, the team analyzed single-cell transcriptomes—snapshots of active genes in individual cells—from six mammalian species representing key branches of the mammalian evolutionary tree. These included mice and guinea pigs (rodents), macaques and humans (primates), and two more unusual mammals: the tenrec (an early placental mammal) and the opossum (a marsupial that split off from placental mammals before they evolved complex placentas).

By analyzing cells at the fetal-maternal interface, the researchers were able to trace the evolutionary origin and diversification of the key cell types involved. Their focus was on two main players: placenta cells, which originate from the fetus and invade maternal tissue, and uterine stromal cells, which are of maternal origin and respond to this invasion.

Using molecular biology tools, the team identified distinct genetic signatures—patterns of gene activity unique to specific cell types and their specialized functions. Notably, they discovered a genetic signature associated with the invasive behavior of fetal placenta cells that has been conserved in mammals for more than 100 million years.

Part 1

This finding challenges the traditional view that invasive placenta cells are unique to humans, and reveals instead that they are a deeply conserved feature of mammalian evolution. During this time, the maternal cells weren't static, either. Placental mammals, but not marsupials, were found to have acquired new forms of hormone production, a pivotal step toward prolonged pregnancies and complex gestation, and a sign that the fetus and the mother could be driving each other's evolution.
To better understand how the fetal-maternal interface functions, the study tested two influential theories about the evolution of cellular communication between mother and fetus.

The first, the "Disambiguation Hypothesis," predicts that over evolutionary time, hormonal signals became clearly assigned to either the fetus or the mother—a possible safeguard to ensure clarity and prevent manipulation. The results confirmed this idea: certain signals, including WNT proteins, immune modulators, and steroid hormones, could be clearly traced back to one source tissue.
The second, the "Escalation Hypothesis" (or "genomic conflict"), suggests an evolutionary arms race between maternal and fetal genes—with, for example, the fetus boosting growth signals while the maternal side tries to dampen them. This pattern was observed in a small number of genes, notably IGF2, which regulates growth. On the whole, evidence pointed to fine-tuned cooperative signaling.

These findings suggest that evolution may have favored more coordination between mother and fetus than previously assumed.
The so-called mother-fetus power struggle appears to be limited to specific genetic regions and there absolutely isn't any conflict.

Daniel J. Stadtmauer et al, Cell type and cell signalling innovations underlying mammalian pregnancy, Nature Ecology & Evolution (2025). DOI: 10.1038/s41559-025-02748-x

Part 2

This material emits infrared light better than it absorbs it, without violating the laws of physics

New results published in the journal Physical Review Letters detail how a specially designed metamaterial was able to tip the normally equal balance between thermal absorption and emission, enabling the material to better emit infrared light than absorb it.

At first glance, these findings appear to violate Kirchhoff's law of thermal radiation, which states that—under specific conditions—an object will absorb infrared light (absorptivity) in one direction and emit it (emissivity) with equal intensity in another, a phenomenon known as reciprocity.

Over the past decade, however, scientists have begun exploring theoretical designs that, under the right conditions, could allow materials to break reciprocity. Understanding how a material absorbs and emits infrared light (heat) is central to many fields of science and engineering. Controlling how a material absorbs and emits infrared light could pave the way for advances in solar energy harvesting, thermal cloaking devices, and other technologies.

Pioneering experiments conducted by a team of researchers in 2023 yielded tantalizing results. By using a single layer of the magneto-optical material indium arsenide (InAs) and subjecting it to a powerful magnetic field of about one tesla (slightly less powerful than an MRI machine but about 100,000 times more powerful than Earth's magnetic field), the team successfully achieved nonreciprocity. Though this confirmed theoretical predictions, the effect was weak and only operated under a very narrow set of conditions.

The newly reported design succeeded in doubling the effect seen previously, making it the first reported observation of "strong" nonreciprocal thermal emission.

To achieve this record-breaking result, researchers created a metamaterial made of five, 440-nanometer-thick layers of electron-doped indium gallium arsenide (InGaAs). The doping concentration increased as the depth increased. The InGaAs layers were then transferred to a silicon substrate.

The sample was then studied with a custom-designed angle-resolved magnetic thermal emission spectroscopy (ARMTES) set up, which heated the sample to 540 Kelvin (512 Fahrenheit) and subjected it to a 5 tesla magnetic field.

The researchers then measured the nonreciprocity of the material, demonstrating that it exhibited twice the effect previously reported. This effect persisted over a wide range of angles and a broad range of infrared wavelengths (from 13 to 23 microns).

This experiment for the first time realizes strong nonreciprocal emission, with nonreciprocity as high as 0.43, which is much higher than nonreciprocity in literature.

Zhenong Zhang et al, Observation of Strong Nonreciprocal Thermal Emission, Physical Review Letters (2025). DOI: 10.1103/PhysRevLett.135.016901

New neurons continue to form in the adult human hippocampus: Study

A study in the journal Science presents compelling new evidence that neurons in the brain's memory center, the hippocampus, continue to form well into late adulthood. The research from Karolinska Institutet in Sweden provides answers to a fundamental and long-debated question about the human brain's adaptability.

The hippocampus is a brain region that is essential for learning and memory and involved in emotion regulation. Back in 2013, a research group showed in a high-profile study that new neurons can form in the hippocampus of adult humans. The researchers then measured carbon-14 levels in DNA from brain tissue, which made it possible to determine when the cells were formed.

In the new study, the researchers combined several advanced methods to examine brain tissue from people aged 0 to 78 years from several international biobanks. They used a method called single-nucleus RNA sequencing, which analyzes gene activity in individual cell nuclei, and flow cytometry to study cell properties. By combining this with machine learning, they were able to identify different stages of neuronal development, from stem cells to immature neurons, many of which were in the division phase.

To localize these cells, the researchers used two techniques that show where in the tissue different genes are active: RNAscope and Xenium. These methods confirmed that the newly formed cells were located in a specific area of the hippocampus called the dentate gyrus. This area is important for memory formation, learning and cognitive flexibility.

The results show that the progenitors of adult neurons are similar to those of mice, pigs and monkeys, but that there are some differences in which genes are active. There were also large variations between individuals—some adult humans had many neural progenitor cells, others hardly any at all.

This gives us an important piece of the puzzle in understanding how the human brain works and changes during life.

 Ionut Dumitru et al, Identification of proliferating neural progenitors in the adult human hippocampus, Science (2025). DOI: 10.1126/science.adu9575.

A single genetic mutation may have made humans more vulnerable to cancer than chimpanzees

New research has uncovered an evolutionary change that may explain why certain immune cells in humans are less effective at fighting solid tumors compared to non-human primates. This insight could lead to more powerful cancer treatments.

The study was published in Nature Communications. It revealed a tiny genetic difference in an immune protein called Fas Ligand (FasL) between humans and non-human primates.

This genetic mutation makes the FasL protein vulnerable to being disabled by plasmin, a tumor-associated enzyme. This vulnerability seems unique to humans and is not found in non-human primates, such as chimpanzees.

The evolutionary mutation in FasL may have contributed to the larger brain size in humans. But in the context of cancer, it was an unfavorable trade-off because the mutation gives certain tumors a way to disarm parts of our immune system.

FasL is an immune cell membrane protein that triggers a programmed cell death called apoptosis. Activated immune cells, including CAR-T cells made from a patient's immune system, use apoptosis to kill cancer cells.
The UC Davis team discovered that in human genes, a single evolutionary amino acid change—serine instead of proline at position 153—makes FasL more susceptible to being cut and inactivated by plasmin.

Plasmin is a protease enzyme that is often elevated in aggressive solid tumors like triple negative breast cancer, colon cancer and ovarian cancer.

This means that even when human immune cells are activated and ready to attack the tumor cells, one of their key death weapons—FasL—can be neutralized by the tumor environment, reducing the effectiveness of immunotherapies.

The findings may help explain why CAR-T and T-cell-based therapies can be effective in blood cancers but often fall short in solid tumors. Blood cancers often do not rely on plasmin to metastasize, whereas tumors like ovarian cancer rely heavily on plasmin to spread the cancer.

Significantly, the study also showed that blocking plasmin or shielding FasL from cleavage can restore its cancer-killing power. That finding may open new doors for improving cancer immunotherapy.

By combining current treatments with plasmin inhibitors or specially designed antibodies that protect FasL, scientists may be able to boost immune responses in patients with solid tumors.

Brice E. N. Wamba et al, Evolutionary regulation of human Fas ligand (CD95L) by plasmin in solid cancer immunotherapy, Nature Communications (2025). DOI: 10.1038/s41467-025-60990-0

Burns and fireworks injuries: What to do when seconds count

This is what experts advice....

From a barbecue explosion to a severe firework injury, a lot can go wrong when celebrating.

When it does, minutes—even seconds—can significantly impact the extent of the injury. Although prevention is key,  response is also essential.

Alcohol impairs your reaction time. 

If a firework or sparkler injures an eye, immediately protect it from pressure or further trauma by placing a cup or makeshift device over it. Don't try to cover it with a towel or anything that touches the eye.

More than a third of firework burns are to the hands and fingers. Should a firework go off in your hand, wrap it in a clean towel and keep it covered until you get to the hospital.

If you catch on fire, from a firework, bonfire, barbecue or cooking incident,  immediately stop, drop and roll.

A lot of people like to run and jump in the water. That's not always the best thing. Unless you're standing on a dock or on the edge of a pool, those few seconds it's going to take you to run to the water, you're burning that whole time. It's much more effective to stop, drop, and roll.

Experts also advise against icing a burn, which can cause further damage.

You can run normal temperature water over it, and then if it's very serious, of course, call emergency ambulance or seek medical care.

If running water isn't accessible, a cool, wet cloth can be used as an alternative. However, once the initial pain subsides, you should replace the damp towel with a clean, dry cloth to prevent the burn from becoming infected.

Missing beneficial bacteria in infant guts linked to rising asthma and allergy cases

Nearly one in four infants lacks enough healthy gut bacteria essential for training their immune systems, putting them at greater risk of developing non-communicable diseases (NCDs) such as allergies, asthma, and eczema by age 2.

Bifidobacteria are among the first group of good bacteria to colonize the human gut, and their presence has been linked to positive health outcomes for the host, including protection against metabolic diseases, gastrointestinal tract infections, and inflammation.

A recent study published in Communications Biology analyzed the gut microbiomes of 412 infants, selected to represent the diverse demographics of the U.S, and found a widespread deficit of Bifidobacteria in infants. Long-term health data from the infants suggested that a lack of detectable Bifidobacteria in infants may contribute to the development of atopy, a genetic predisposition to developing allergic diseases.

Global estimates suggest that up to 40% of the population has some form of allergy to substances present in the environment—pollen, dust, mites, or animal dander. The last few decades have also witnessed a growing prevalence of allergic conditions among children, ranging from seasonal allergies with mild symptoms, such as a runny nose, sneezing, and itchy eyes, to severe eczema and life-threatening food allergies that can send someone into an anaphylactic shock.

Emerging data suggests that the rise in such NCDs actually begins during the first 1,000 days of a child's life—inside the mother's womb and through the first two years of life. Scientists think that while environmental and lifestyle changes play a role, a key factor may be disruptions in the gut microbiome. In infants, this disruption includes the widespread loss of certain beneficial strains of Bifidobacterium that are essential for early immune development and long-term health.

A baby's mode of delivery (C-section or vaginal birth), whether they were breastfed or formula-fed, and exposure to antibiotics can shape the diversity of their gut microbiome, a factor that has been linked to health issues later in life, including allergies, autoimmune diseases, obesity.

Data analysis revealed that 25% of  infants between 1 and 3 months of age were deficient in Bifidobacterium, and the deficiency was more pronounced in C-section births (35%) than in vaginal births (19%). In C-section infants, the beneficial bacteria were often replaced by potentially pathogenic bacteria that are known to use up human milk oligosaccharides, components in breast milk that shape the infant gut microbiome.
They also found that microbiomes rich in Bifidobacterium had fewer antimicrobial-resistant and disease-causing genes, along with more beneficial metabolic profiles.

The researchers highlight that while the term dysbiosis or imbalance in the microbiome is still up for debate, the strong correlation between microbiome composition and infant health suggests that the absence of these key Bifidobacterium strains represents a true dysbiosis in early life.

John B. Jarman et al, Bifidobacterium deficit in United States infants drives prevalent gut dysbiosis, Communications Biology (2025). DOI: 10.1038/s42003-025-08274-7

Scientists use lightning to make ammonia out of thin air

 Researchers have harnessed human-made lightning to develop a more efficient method of generating ammonia—one of the world's most important chemicals. Ammonia is also the main ingredient of fertilizers that account for almost half of all global food production.

The research was published in Angewandte Chemie International edition.

The team have successfully developed a more straightforward method to produce ammonia (NH₃) in gas form. Previous efforts by other laboratories produced ammonia in a solution (ammonium, NH₄⁺), which requires more energy and processes to transform it into the final gas product.

The current method to generate ammonia, the Haber-Bosch process, comes at great climate cost, leaving a huge carbon footprint. It also needs to happen on a large scale and close to sources of cheap natural gas to make it cost-effective.

Naturally occurring ammonia (mostly in the form of bird droppings) was once so high in demand it fueled wars.

The invention of the Haber-Bosch process in the 19th century made human-made ammonia possible and revolutionized modern agriculture and industry. Currently, 90% of global ammonia production relies on the Haber-Bosch process.

Industry's appetite for ammonia is only growing. For the past decade, the global scientific community has wanted to uncover a more sustainable way to produce ammonia that doesn't rely on fossil fuels.

In this new research scientists have successfully developed a method that allows air to be converted to ammonia in its gaseous form using electricity. 

Part 1

The plasma-based method this team developed uses electricity to excite nitrogen and oxygen molecules in the air. The team then passes these excited molecules to the membrane-based electrolyzer to convert the excited molecules to ammonia.

The researchers said this is a more straightforward pathway for ammonia production. This new approach is a two-step process, namely combining plasma and electrolysis.

 Wanping Xu et al, Regulating Multifunctional Oxygen Vacancies for Plasma‐Driven Air‐to‐Ammonia Conversion, Angewandte Chemie International Edition (2025). DOI: 10.1002/anie.202508240

Part 2

Circadian disruption by night light linked to multiple cardiovascular outcomes

Researchers have linked brighter night-time light exposure to elevated risks of five major cardiovascular diseases.

Circadian rhythms govern fluctuations in blood pressure, heart rate, platelet activation, hormone secretion, and glucose metabolism. Long-term disruption of those rhythms in animal and human studies have produced myocardial fibrosis, hypertension, inflammation, and impaired autonomic balance.

In the study, "Personal night light exposure predicts incidence of cardiovascular diseases in >88,000 individuals," posted on medRxiv, researchers conducted a prospective cohort analysis to assess whether day and night light exposure predicts incidence of cardiovascular diseases and whether relationships vary with genetic susceptibility, sex, and age.

Brighter nights showed dose-response associations with higher risk across all five outcomes. Participants classified in the 90–100th percentile of night-time light exposure experienced 23–32% higher hazard for coronary artery disease, 42–47% for myocardial infarction, 45–56% for heart failure, 28–32% for atrial fibrillation, and 28–30% for stroke compared with those in the 0-50th percentile.

Relationships persisted after controlling for physical activity, smoking, alcohol, diet, sleep duration, socioeconomic status, and genetic risk. Women displayed stronger associations for heart failure and coronary artery disease whereas younger participants showed stronger associations for heart failure and atrial fibrillation.

Authors propose circadian misalignment induced by unnatural light may trigger metabolic and vascular perturbations that elevate cardiovascular risk. Impaired glucose tolerance and heightened diabetes susceptibility may foster endothelial dysfunction and atherosclerosis.
Light-driven hypercoagulability could increase thromboembolic events, while sustained elevation of 24-hour blood pressure may damage vascular endothelium and provoke myocardial hypertrophy. Conflicting timing signals to sinoatrial and atrioventricular nodes may amplify arrhythmic vulnerability.

Avoiding bright light during habitual sleep times may serve as a practical addition to established cardiovascular prevention strategies, according to the authors, who call for circadian-informed lighting guidance in homes, hospitals, and urban planning.

 Daniel P Windred et al, Personal night light exposure predicts incidence of cardiovascular diseases in >88,000 individuals, medRxiv (2025). DOI: 10.1101/2025.06.20.25329961

Massive study detects AI fingerprints in millions of scientific papers

Chances are that you have unknowingly encountered compelling online content that was created, either wholly or in part, by some version of a Large Language Model (LLM). As these AI resources, like ChatGPT and Google Gemini, become more proficient at generating near-human-quality writing, it has become more difficult to distinguish between purely human writing from content that was either modified or entirely generated by LLMs.

This spike in questionable authorship has raised concerns in the academic community that AI-generated content has been quietly creeping into peer-reviewed publications.

To shed light on just how widespread LLM content is in academic writing, a team of researchers analyzed more than 15 million biomedical abstracts on PubMed to determine if LLMs have had a detectable impact on specific word choices in journal articles.

Their investigation revealed that since the emergence of LLMs there has been a corresponding increase in the frequency of certain stylist word choices within the academic literature. These data suggest that at least 13.5% of the papers published in 2024 were written with some amount of LLM processing. The results appear in the open-access journal Science Advances.

The team also identified notable differences in LLM usage between research fields, countries, and venues.

Dmitry Kobak et al, Delving into LLM-assisted writing in biomedical publications through excess vocabulary, Science Advances (2025). DOI: 10.1126/sciadv.adt3813

Metabolic differences in male and female muscles may explain diabetes variations

The skeletal muscles of men and women process glucose and fats in different ways. A study conducted recently provides the first comprehensive molecular analysis of these differences. The results, published in Molecular Metabolism, possibly give an explanation for why metabolic diseases such as diabetes manifest differently in women and men—and why they respond differently to physical activity.

Skeletal muscles are far more than just "movement driving motors." They play a central role in glucose metabolism and therefore also in the development of type 2 diabetes. This is due to the fact that around 85% of insulin-dependent glucose uptake takes place in the muscles. This means that if muscle cells react less sensitively to insulin, for example in the case of insulin resistance, glucose is less easily absorbed from the blood. This process is specifically counteracted by physical activity.

The degree to which muscles work differently in women and men has long been underestimated. It is precisely this issue which has now been investigated by researchers now. 

The result of the work: The first training session triggered a stronger stress response at the molecular level in men, which became manifest in the increased activation of stress genes and the increase in the muscle protein myoglobin in the blood. In addition, male muscles showed a distinct pattern of what are called fast-twitch fibers, which are designed for short-term, intensive exercise and preferably use glucose as an energy source.

Women had significantly higher amounts of proteins that are responsible for the absorption and storage of fatty acids: an indication of more efficient fat utilization. After eight weeks of regular endurance training, the muscles of both sexes matched and the muscle fiber-specific differences decreased. At the same time, women and men produced more proteins that promote the utilization of glucose and fat in the mitochondria, the "power plants of the cells."

These adjustments indicate an overall improvement in metabolic performance, which can help to reduce the risk of type 2 diabetes. 

Simon I. Dreher et al, Sex differences in resting skeletal muscle and the acute and long-term response to endurance exercise in individuals with overweight and obesity, Molecular Metabolism (2025). DOI: 10.1016/j.molmet.2025.102185

 Image rotation in plasma observed

Light sometimes appears to be "dragged" by the motion of the medium through which it is traveling. This phenomenon, referred to as "light dragging," is typically imperceptible when light is traveling in most widely available materials, as the movement is significantly slower than the speed of light. So far, it has thus proved difficult to observe in experimental settings.

Physicists recently observed a specific type of light dragging known as image rotation in a plasma-based system.

Their observation, outlined in a paper published in Physical Review Letters, was made using magnetohydrodynamic (MHD) waves that propagate in a magnetized plasma, known as Alfvén waves.

Using recently demonstrated plasma rotation control capabilities in the Large Plasma Device at UCLA, the researhcers managed to show that they can indeed rotate the wave pattern left and right by some tens of degrees by controlling the plasma rotation.

To realize image rotation in plasma, the researchers leveraged the naturally slow velocity with which Alfvén waves travel. They specifically employed a system in which Alfvén waves are launched in a plasma whose rotation can be controlled using electrically charged electrodes brought in contact with the plasma.

Their efforts led to the observation of image rotation. In other words, they found that the Alfvén waves' transverse structure appeared to twist.

Interestingly, they also found that these effects surprisingly matched those predicted by theories explaining light dragging in isotropic systems, media far simpler than plasmas that exhibit the same properties irrespective of the directions they are observed from, demonstrating a broader validity of these results.

 Renaud Gueroult et al, Image Rotation in Plasmas, Physical Review Letters (2025). DOI: 10.1103/swrn-w3yf. On arXiv: arxiv.org/html/2505.18062v1