Scientists chart over 140,000 DNA loops to map human chromosomes in the nucleus
Over 140,000 DNA looping interactions were mapped in human embryonic stem cells and fibroblasts, providing a detailed 3D organization of chromosomes within the nucleus. Computational models now predict genome folding from DNA sequence alone, clarifying how chromatin loops influence gene regulation and how genetic variations may alter genome structure and function.

Job Dekker et al, An integrated view of the structure and function of the human 4D nucleome, Nature (2025). DOI: 10.1038/s41586-025-09890-3

Elzo de Wit, Systematic maps reveal how human chromosomes are organized, Nature (2025). DOI: 10.1038/d41586-025-03808-9

Two ancient human species came out of Africa together, not one, suggests new study

The textbook version of the "Out of Africa" hypothesis holds that the first human species to leave the continent around 1.8 million years ago was Homo erectus. But in recent years, a debate has emerged suggesting it wasn't a single species, but several. New research published in the journal PLOS One now hopes to settle the matter once and for all.

The debate centers on the Dmanisi fossils, five skulls found in the Republic of Georgia between 1999 and 2005, which belong to some of the oldest humans ever found outside Africa. The problem is that they don't look alike. Some are larger than others, particularly Skull 5, which has a tiny braincase but a massive, protruding face. Some researchers explain this as a difference in sexes within the same species, while others argue that it represents two distinct species living together.

To provide much-needed clarity, researchers studied the teeth of three Dmanisi specimens. The reason is that, generally, skulls are not always the best species identifiers because bone is fragile and can be warped and crushed. Dentition is far more useful because enamel is the hardest biological substance produced by humans, and everything from the shape and size of individual teeth can be used to identify a species.

The team focused on the surface area (dental crown) of the back teeth (premolars and molars) of the Dmanisi specimens that had sufficient dental remains for analysis. They compared these to a database of 122 other fossil specimens, including Australopithecus and several other Homo species. Then, using a statistical sorting tool, they analyzed 583 teeth to create a biological map and determine whether the Dmanisi fossils belonged to a single family or to other branches of our family tree.

The map revealed that these ancient remains were not from a single group. Skull 5, with its large jaw, was grouped with Australopiths, a more primitive ape-like ancestor. The other two specimens were more human-like. Because of this, the study authors support using the names Homo georgicus for Skull 5 and Homo caucasi for the human-like group.
To ensure the differences weren't just between males and females, the team compared the fossils with those of great apes. In some animals, like gorillas, males are much larger than females but still have the same basic teeth. The differences between the Dmanisi teeth were so great that male-female differences within the same group couldn't explain them.
Part 1

The postcanine dental crown area analysis of the Dmanisi hominin fossils... supports the hypothesis of distinct species coexisting temporally at the site (Homo caucasi and Homo georgicus). This possibility challenges the prevailing model of Homo erectus migration out of Africa..." commented the researchers in their paper.

While the research lends weight to the idea that two species left Africa at roughly the same time, more specimens may be needed before a consensus is reached.

Victor Nery et al, Testing the taxonomy of Dmanisi hominin fossils through dental crown area, PLOS One (2025). DOI: 10.1371/journal.pone.0336484

Part 2

**

Some mammals can hit pause on a pregnancy—understanding how that happens could help us treat cancer
Embryonic diapause allows some mammals to pause development by activating a molecular brake that suppresses differentiation pathways, maintaining stem cell pluripotency during metabolic stress. This mechanism involves the displacement of Capicua, enabling genes that inhibit the MAP kinase pathway. The findings suggest similar dormancy programs may underlie long-term survival in immune, stem, and cancer cells.

Tuo Zhang et al, Transcriptional derepression of negative regulators of MAP kinase supports maintenance of diapause ES cells in the pluripotent state, Genes & Development (2025). DOI: 10.1101/gad.353143.125

**

Whale, dolphin strandings show widespread disease, trauma
Analysis of 272 cetacean strandings in the Pacific Islands from 2006 to 2024 found that over 65% involved disease or human-caused trauma. Disease accounted for 62% of cases, with infectious agents like morbillivirus and brucella affecting multiple species. Human-related trauma, including vessel strikes and debris ingestion, contributed to 29% of strandings.

From land-borne pathogens to high-speed vessel strikes, Pacific whales and dolphins are caught in a "perfect storm" where human-caused trauma and infectious diseases were found in more than 65% of investigated strandings.

A study spanning nearly two decades by  researchers provides insights into the threats whales and dolphins face in the Pacific Islands.

Based on 272 stranding investigations of 20 cetacean species between 2006 and 2024, the study provides foundational data to better manage and conserve Hawaiʻi's whales and dolphins. The findings are published in the journal Diseases of Aquatic Organisms.

Over 18 years, scientists examined more than three-quarters of the stranded whales and dolphins to understand why they died. Most cases (62%) were linked to diseases, and about half of those animals were in poor body condition due to long-term illness.
Infectious agents proved to be a significant threat, affecting 11 different species, including striped dolphins and Longman's beaked whales. Two of the most concerning pathogens were morbillivirus and brucella, which can cause serious brain and lung problems in marine mammals.

Toxoplasmosis—a parasite that infects warm-blooded animals and spreads through cat feces across the environment—was responsible for the deaths of two spinner dolphins and one bottlenose dolphin.

The study revealed that 29% of all strandings were linked to anthropogenic (human-caused) trauma. Vessel strikes were a significant risk, resulting in fatal vertebral and skull fractures for seven individuals, including two pygmy sperm whales, two humpback whale calves, a goose-beaked whale, a spinner dolphin and a striped dolphin.

Interactions with marine debris and fisheries were confirmed as fatal in multiple cases, including a sperm whale that died from plastic and fishery debris blocking its stomach and a bottlenose dolphin that died after a fishhook tore into it.

Kristi West et al, Pacific Islands cetaceans: a review of strandings from 2006-2024, Diseases of Aquatic Organisms (2025). DOI: 10.3354/dao03877

Gut bacteria may play role in bipolar depression by directly influencing brain connectivity

Bipolar disorder (BD) is a psychiatric disorder characterized by extreme mood changes. Individuals diagnosed with BD typically alternate between periods of high energy, euphoria, irritability and/or impulsivity (i.e., manic episodes) and others marked by feelings of sadness, low energy, and hopelessness (i.e., depression).

While there are now several medications that can help patients to manage the disorder and stabilize their mood, many of these drugs have side effects and dosages often need to be periodically adjusted. Recent studies suggest that the bacteria and microorganisms living in the digestive system, also known as gut microbiota, play a key role in mental health and might also contribute to some symptoms of BD.

Researchers  recently carried out a study investigating the possible connection between gut microbiota and the depressive episodes experienced by people diagnosed with BD. Their findings, published in Molecular Psychiatry, suggest that the microorganisms in the digestive system can directly influence connections between specific brain regions known to be affected by BD depression.

Adequate evidence has shown that gut microbial dysbiosis is an emerging disease phenotype of BD and is closely related to clinical symptoms of this intractable disease, wrote the researchers in their paper.

To explore the link between gut microbiota and BD depression, the researchers collected gut bacteria from individuals diagnosed with BD who were going through a depressive phase. They then transplanted these bacteria into the digestive system of healthy mice.

They found that bipolar depression-like mice presented with a decrease in the density of dendrite spines in medial prefrontal neurons, and translation post-synapse as a key contributor to the changes in synaptic plasticity.

In addition, analysis of synaptic connectivity in the mPFC revealed that compared to control mice, fewer connections were observed between ventral tegmental area and mPFC glutamate neurons and dopamine response was decreased in BD mice.

Notably, the researchers found that after they received the microbiota taken from individuals who were experiencing BD depression, the mice also started exhibiting depression-like behaviors. In addition, neurons in two brain regions known to be implicated in mood regulation, namely the ventral tegmental area (VTA) and the medial prefrontal cortex (mPFC), appeared to be less connected with each other.

The team also observed disruptions in the production of proteins and reduced dopamine signaling. Dopamine signaling (i.e., the release of dopamine) is essential for maintaining motivation and emotional regulation.

The results of this study confirm that microorganisms and bacteria in the gut can influence the connections between neurons in different brain regions. These altered connections could in turn have an impact on motivation, mood regulation and the processing of emotions.

Part1

The team's findings will need to be validated in humans before they can be reliably translated into psychiatric and medical insight. In the future, however, they could potentially help to identify promising pathways for the treatment of depression in patients diagnosed with BD, which are designed to alter their gut microbiota.

Anying Tang et al, Gut microbiota modulates synaptic plasticity, connectivity, and dopamine transmission in the VTA-mPFC pathway in bipolar depression, Molecular Psychiatry (2025). DOI: 10.1038/s41380-025-03398-y.

Part 2

Brain chemistry can reactivate or suppress dormant HIV

Human immunodeficiency virus (HIV) infections are still fairly common and an estimated 40 million people worldwide are currently living with this condition. The HIV virus attacks the body's immune system and thus makes those who contract it more vulnerable to a wide range of infections.

While there is still no known cure for HIV, there are now various treatment options that allow affected patients to live long and healthy lives. When treated with antiretroviral therapy (ART), the virus is known to remain in a latent state, essentially 'hiding' inside cells and forming a reservoir of dormant virus. If the medication is stopped, however, the virus can be re-awoken, causing severe immune deficiencies again.

Researchers have recently been investigating how the brain, particularly tiny molecules and protein-carrying packages released by cells, influence the persistence of HIV. In a new paper, published in Molecular Psychiatry, they presented new findings that shed new light on molecular mechanisms that can either re-ignite or suppress latent HIV.

In their experiments the researchers found that ECs collected from the brains of SIV-infected but untreated macaques strongly re-activated latent virus reservoirs increasing the activity of viral genes, the production of proteins and causing the virus to spread between cells. Interestingly, however, particles extracted from the brains of infected macaques who were treated with cannabinoids were found to suppress the re-activation of the virus.

"Cannabinoids have been shown to inhibit neuroinflammation," said the authors of the research paper. They showed that cannabinoids exert similar anti-inflammatory effects via EVs and in the current study on ECs, we report that ECs isolated from brains (basal ganglia) of rhesus monkeys have this anti-inflammatory effect and that cannabinoids modulate the cargos of the ECs, with resultant effects on latent HIV reservoirs.

Overall, the findings gathered by these researchers suggest that the brain's chemistry, particularly ECs, do play a key role in the reactivation or suppression of dormant HIV. In the future, their work could pave the way for the development of new drugs and therapeutic interventions aimed at better managing, or perhaps even curing, HIV infections.

Wasifa Naushad et al, Extracellular condensates (ECs) are endogenous modulators of HIV transcription and latency reactivation, Molecular Psychiatry (2025). DOI: 10.1038/s41380-025-03354-w.

The global fish trade is spreading 'forever chemicals' around the world

Eating fish may well be good for you, but it carries a hidden risk of exposure to so-called "forever chemicals." A new study published in the journal Science has revealed that the global seafood trade is acting as a massive delivery system for per- and polyfluoroalkyl substances (PFAS), industrial pollutants that persist in the environment for decades.

These forever chemicals are used in many products, from nonstick cookware and cosmetics to food packaging and firefighting foams. They are extremely resistant to breaking down in the environment and have been linked to a variety of serious illnesses such as cancer and liver disease.

PFAS can travel long distances around the planet in the air and through water. Once they wash into the ocean, they are absorbed by tiny organisms at the bottom of the food chain, such as plankton and algae. Because these chemicals do not break down, they accumulate in their bodies, and when small fish eat them, the toxic substances pass up the food chain. Large predatory fish, the kind that end up on our dinner plates, eat these smaller marine creatures, and as a result, the chemical concentrations build up in their tissues and organs.

In their paper, the researchers set out to map how these chemicals move once they are inside the fish. They built a computer model covering 212 different species to track how toxins accumulate up the food chain and then validated this with lab tests on fish from numerous countries. Then the team combined this data with global trade records to see how the fish and PFAS travel from one country to another.

One of the most significant findings was that the international fish trade acts like a global conveyor belt, redistributing PFAS from contaminated regions to consumers thousands of miles away.
Before this study, it was generally assumed that forever chemicals were a local problem. If your country's rivers and seas were clean, then so were the fish. However, a nation with clean water can still be exposed to high levels of PFAS through the seafood it imports from other parts of the world. For example, researchers found that Italians buy only 11% of their fish from Sweden, yet this accounts for more than 35% of their PFAS exposure.

Given that this problem doesn't respect borders, researchers argue that a unified global strategy is needed to protect public health.

Wenhui Qiu et al, Risks of per- and polyfluoroalkyl substance exposure through marine fish consumption, Science (2025). DOI: 10.1126/science.adr0351

Jennifer Sun et al, Reevaluating PFAS exposure risks from marine fish, Science (2025). DOI: 10.1126/science.aed7431

Raindrops form 'sandballs' as they roll downhill, contributing more to erosion than previously thought

We know that the initial splash of raindrops on soil contributes to erosion, but a new study, published in the Proceedings of the National Academy of Sciences, finds that the journey of the raindrop downhill might have an even bigger impact on erosion than the initial splash.

Researchers observed natural raindrops hitting the surface of a hillside and noticed that they collected particles of sand as they rolled downhill. This spurred the researchers to document the event with a camera and then take the idea to the lab.

In the lab, they constructed a 1.2 meter long bed covered with dry silicate sand and tilted at an angle of 30°. The lab conditions enabled the team to properly document the phenomenon by recording the evolution of the raindrops' shapes as they rolled and take precise measurements of the relevant parameters. They found that each raindrop formed what they refer to as "sandballs" and that they took on differing shapes, depending on the conditions, and that the sandballs can move up to 10 times more soil than the initial splash alone.

"In the initial rolling stage, drops rapidly increase their speed and sediment entrainment rate. Under increasing centrifugal force, the rolling drops undergo a metamorphosis: Their rounded shape destabilizes, as both liquid and entrained grains drift away from the core to create sandballs," the study authors write in their paper.

The researchers found that the sandy raindrops formed two distinct shapes: a peanut shape and a doughnut shape. Peanuts occurred at comparably lower velocities and maintained their grains at the surface of the drop. They only gather grains up to a certain point and then usually plateau.

"Once their mass plateaus, peanuts continue to increase their angular velocity as they roll; this sometimes causes a shift in their mode of motion, triggering an additional phase of mass accumulation. Other times, peanuts break, tumble slower or settle. If peanuts survive to the end of the slope and roll onto a flat surface, they immediately fall apart," the study authors explain.

Instead of only gathering grains at the surface, doughnut-shaped drops absorb sand grains into their interior volume, making them more dense and opaque in appearance. The researchers call the emergence of these kinds of drops "unexpected."

The team found that these drops destabilize into the doughnut shape from axisymmetric radial stretching. These shapes only occur at very high spin rates in pure-liquid drops, but occurred at slightly lower rates in the lab experiments due to the water-glycerol mixture used in the lab-based drops.

Part 1

The study authors write, "Fully developed doughnuts continue to speed up (above 1 m/s), until a point where they sometimes break apart in an apparent fracture process. This breakage occurs when the tensile force driven by the centrifugal sandball stretching overcomes the strength of capillary bonds, producing child sandballs that carve their own track as they tumble down the slope."

Studying the shapes that raindrops take on as they tumble down dry dirt hills might seem frivolous, but these dynamics have real implications for soil erosion models, which are used for predicting soil loss from rain. These models help with conservation planning, land management, and environmental assessment by estimating erosion rates, identifying more vulnerable areas, designing control measures and evaluating land health in agriculture. 

Bertil Trottet et al, Sandball genesis from raindrops, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2519392122

Part 2

New species are being discovered faster than ever before, study suggests

According to a new  study published in Science Advances, scientists are discovering species quicker than ever before, with more than 16,000 new species discovered each year. The trend shows no sign of slowing, and the team behind the new paper predicts that the biodiversity among certain groups, such as plants, fungi, arachnids, fishes and amphibians is richer than scientists originally thought.

Researchers  analyzed the taxonomic histories of roughly 2 million species, spanning all groups of living organisms. Between 2015 and 2020—the most recent period with comprehensive data—researchers documented an average of more than 16,000 new species each year, including more than 10,000 animals (dominated by arthropods and insects), 2,500 plants and 2,000 fungi.

and the  good news is that this rate of new species discovery far outpaces the rate of species extinctions, which researchers calculated to about 10 per year.

These thousands of newly found species each year are not just microscopic organisms, but include insects, plants, fungi and even hundreds of new vertebrates.

The team also analyzed the rates of new species appearing over time to project how many species will be discovered and described in the future. For example, they projected that there might be as many as 115,000 fish species and 41,000 amphibian species, even though there are only about 42,000 fish and 9,000 amphibian species described now. They also projected that the final number of plant species might be over a half million.

Discovering new species is important because these species can't be protected until they're scientifically described. 

Additionally, the discovery of new species contributes to finding new natural products for human benefit.

Spider and snake venoms and many plants and fungi also contain natural products with potential medicinal applications, including treatments for pain and cancer.

Beyond medicine, many species have adaptations that can inspire human inventions, such as materials mimicking the "super-clinging" feet that allow geckos to climb up vertical surfaces. Scientists are still just scratching the surface of what these species can do for humanity.

Xin Li et al, The past and future of known biodiversity: Rates, patterns, and projections of new species over time, Science Advances (2025). DOI: 10.1126/sciadv.adz3071

Fathers' microplastics exposure tied to their children's metabolic problems

Paternal exposure to microplastics in mice leads to metabolic dysfunction in offspring, with female progeny showing increased susceptibility to diabetes and altered gene expression linked to inflammation. These effects are associated with changes in sperm small noncoding RNAs, indicating a mechanism for transgenerational impact of environmental pollutants.

A new study has shown for the first time that a father's exposure to microplastics (MPs) can trigger metabolic dysfunctions in his offspring. The research, conducted using mouse models, highlights a previously unknown pathway through which environmental pollutants impact the health of future generations.

While MPs have already been detected in human reproductive systems, the study, published in the Journal of the Endocrine Society, is the first to bridge the gap between paternal exposure to MPs and the long-term health of the next generation (the "F1 offspring").

MPs are tiny plastic particles (less than 5 millimeters) resulting from the breakdown of consumer products and industrial waste. Metabolic disorders refer to a cluster of conditions—including increased blood pressure, high blood sugar, and excess body fat—that increase the risk of heart disease and diabetes.

Key findings and sex-specific effects The research team found that female offspring of male mice exposed to MPs were significantly more susceptible to metabolic disorders than offspring of unexposed fathers, despite all offspring being fed the same high-fat diet.

"The exact reasons for this sex-specific effect are still unclear", say the researchers. They observed upregulation of pro-inflammatory and pro-diabetic genes in their livers—genes previously linked to diabetes. These changes were not seen in male offspring.
The research team found that while male offspring did not develop diabetes, they showed a slight yet significant decrease in fat mass. Female offspring showed decreased muscle mass alongside increased diabetes.

Seung Hyun Park et al, Paternal microplastic exposure alters sperm small non-coding RNAs and affects offspring metabolic health in mice, Journal of the Endocrine Society (2025). DOI: 10.1210/jendso/bvaf214

Why mangoes fall before they're ripe—and how science is helping them hang on

 Why your mango tree drops fruit before it's ripe? Each season, mango growers across the world watch helplessly as millions of mangoes fall to the ground too early.

These mangoes never ripen properly, never reach consumers, and represent a major loss—both economically and environmentally.
Premature fruit drop is a major contributor to low mango yields, with as little as 0.1% of fruits reaching maturity. This costs growers millions and wastes valuable resources.
As climate stress intensifies, understanding why fruit is lost before harvest has global significance. It affects everything from food security to farm profitability.

Its sensitivity to environmental stress makes it vulnerable in a less predictable and more extreme climate. Drought, heat waves, and even leaf loss can influence a natural process that leads to fruit drop.

Just like humans, plants rely on hormones to keep things growing and functioning smoothly.

These chemical messengers help regulate everything from flowering to fruit development.

But when plants experience stress, hormone levels shift. The plant starts reallocating resources to survive. Dropping fruit is often one of the first sacrifices.

One key resource that plants reallocate is carbohydrates. Developing fruit requires a steady supply of sugars, but under stress—such as leaf damage or water scarcity—the tree may struggle to produce or transport enough.

This can trigger fruit drop, as the plant prioritizes survival over reproduction.

Stress not only disrupts carbohydrate supply but also interferes with the hormonal balance in mango trees. This triggers what we call a molecular "quit signal": a message from the plant to let go of its fruit.

This signal is a part of a complex network of gene activity and hormonal cues that help the tree decide when to shed fruit.

Researchers are studying the molecular pathways behind this signal by analyzing gene signals from mango pedicel tissue—the stem that connects the fruit to the tree.

This tissue acts like a control center, managing the flow of nutrients and signals between the tree and the developing fruit. It's where the tree and fruit stay in touch, especially during stress.

By analyzing which genes are turned on or off, we can pinpoint the molecular signals involved in fruit drop, particularly those related to hormones.

This helps us move from just observing fruit drop to developing tools to control it.

One promising solution is the use of plant growth regulators, which are synthetic versions of plant hormones.

These can be applied to mango trees to help stabilize hormone levels during stressful conditions.

It's a bit like giving the tree a hormonal pep talk, encouraging it to hold onto fruit even when times are tough.

Applying plant growth regulators during flowering, before fruit has fully emerged, was more effective than applying them later in the season.

This early intervention helped reinforce the hormonal signals that support fruit retention. Initial trials have increased tree yield by up to 17%.

Even small-scale growers might one day use targeted treatments to help their trees hold on to fruit longer.

Part 1

For consumers, reducing fruit drop means better access to fresh, affordable produce. For growers, it's about staying viable in an increasingly unpredictable climate. And for policymakers, it's about preparing the horticultural industry for the challenges ahead.

Importantly, fruit drop isn't unique to mangoes. Apples, citrus, and avocados also suffer losses due to hormonal imbalances triggered by environmental stress.

Better understanding the molecular mechanisms controlling fruit drop in mango, could benefit a wide range of fruit crops globally as the climate changes.

This article is republished from THE CONVERSATION under a Creative Commons license. Read the original article.

Part 2

**

Why do reindeer eyes change colour?

Get this right: 

Over 50% of Heart Attacks in Younger Women Aren't From Clogged Arteries

Traditionally, most heart attacks have been blamed on clogged arteries causing atherothrombosis – where blood clots block flow to the heart.
But research suggests we may be underestimating the role of other causes, particularly in younger adults.

Scientists from the Mayo Clinic in the US analyzed 1,474 heart attack events in people aged 65 or younger, recorded between 2003 and 2018 in Olmsted County, Minnesota. By carefully reviewing medical records and imaging, they identified a primary cause behind each case.

Strikingly, more than half of heart attacks in women were found to have non-atherothrombotic causes.

Atherothrombosis accounted for 75 percent of heart attacks in men, which wasn't surprising. But in women, it was behind 47 percent – less than half. That has major implications for the prevention and treatment of heart attacks.

This research shines a spotlight on heart attack causes that have historically been under-recognized, particularly in women. In women, 34 percent of all heart attack events were attributed to supply/demand mismatch secondary myocardial infarctions (SSDMs) – defined as an imbalance of oxygen supply and demand caused by other stressors on the body, such as anemia or an infection.

Among the other factors significantly contributing to heart attacks were spontaneous coronary artery dissections (SCADs), where tears in artery walls collect blood, and embolisms (blood clots traveling from other areas of the body).

Causes of Myocardial Infarction in Younger Patients: Troponin-Eleva...

Why the human brain matures slower than its primate relatives

The human brain is a fascinating and complex organ that supports numerous sophisticated behaviors and abilities that are observed in no other animal species. For centuries, scientists have been trying to understand what is so unique about the human brain and how it develops over the human lifespan.

Researchers have recently set out to study both the human and macaque brain, comparing their development over time using various genetic and molecular analysis tools. Their paper, published in Nature Neuroscience, highlights some key differences between the two species, with the human pre-frontal cortex (PFC) developing slower than the macaque PFC.

The researchers collected several samples of brain tissue that was surgically removed from the PFC of macaques and humans at different stages after birth. The human subjects were children with epilepsy who were undergoing surgical procedures as part of their treatment plan.

The researchers analyzed the expression of genes in single cells taken from the tissues they collected, as well as chromatin accessibility (i.e., how open DNA is within individual cells). They also mapped the expression of genes across the entire brain tissues, using a technique known as spatial transcriptomics, and looked at the types of cells that were present.

"Integrative analyses outlined species-specific dynamic trajectories of different cell types, highlighting key windows and gene regulatory networks for processes such as synaptogenesis, synaptic pruning and gliogenesis," wrote the authors in their paper.

The researchers' analyses revealed that the human PFC takes longer to develop than that of macaques. They also observed that glial progenitors (i.e., stem-like cells that later divide and develop into specific types of glial cells) proliferate more in humans.
"We identified regulatory correlates of the prolonged development of human PFC relative to macaques," wrote the researchers. "Glial progenitors showed higher proliferation capability in humans compared to macaques, associated with distinct gene expression profiles. Furthermore, we uncovered cell types and lineages most susceptible to neurodevelopmental and neuropsychiatric disorders, focusing on transcription factors with human-specific expression features."

Part 1

they gathered new valuable observations that could explain in greater detail known differences between the brain functions of humans and other primates. Notably, the researchers also identified transcription factors that modulate the development of the human brain but not of macaques, while also pinpointing types of cells in human tissues that are known to be affected in the brains of patients with specific disorders.

Jiyao Zhang et al, Single-cell spatiotemporal transcriptomic and chromatin accessibility profiling in developing postnatal human and macaque prefrontal cortex, Nature Neuroscience (2025). DOI: 10.1038/s41593-025-02150-7

Part 2

**

"Our discoveries shed light on human-specific regulatory programs extending postnatal cortical maturation through coordinated neuronal and glial development, with implications for cognition and neurodevelopmental disorders," wrote the team.

How do I make clear ice at home? A food scientist shares easy tips

Clear ice forms when water freezes in a single direction, pushing air and impurities to one end, unlike typical home freezing that traps them throughout the cube and causes cloudiness. Using an insulated container to promote directional freezing produces clear ice, while water quality or boiling alone does not prevent cloudiness. Clear ice is denser, melts slower, and resists imparting flavors.

Clear ice is actually made from regular water—what's different is the freezing process.

With a little help from science, you can make clear ice at home, and it's not even that tricky. However, there are quite a few hacks on the internet that won't work. Let's dive into the physics and chemistry involved.

Why ice goes cloudy

Homemade ice is often cloudy because it has a myriad of tiny bubbles and other impurities. In a typical ice cube tray, as freezing begins and ice starts to form inward from all directions, it traps whatever is floating in the water: mostly air bubbles, dissolved minerals and gases.

These get pushed toward the center of the ice as freezing progresses and end up caught in the middle of the cube with nowhere else to go.

That's why when making ice the usual way—just pouring water into a vessel and putting in the freezer—it will always end up looking somewhat cloudy. Light scatters as it hits the finished ice cube, colliding with the concentrated core of trapped gases and minerals. This creates the cloudy appearance.

The point of clear ice

As well as looking nice, clear ice is denser and melts slower because it doesn't have those bubbles and impurities. This also means that it dilutes drinks more slowly than regular, cloudy ice.

Because it doesn't have impurities, the clear ice should also be free from any inadvertent flavors that could contaminate your drink.

Additionally, because it's less likely to crumble, clear ice can be easily cut and formed into different shapes to further dress up your cocktail.

If you've tried looking up how to make clear ice before, you've likely seen several suggestions. These include using distilled, boiled or filtered water, and a process called directional freezing. Here's the science on what works and what doesn't.

Myths about clear ice that don't work

You might think that to get clear ice, you simply need to start out with really clean water. However, a recent study found this isn't the case.

Using boiling water: Starting out with boiling water does mean the water will have less dissolved gases in it, but boiling doesn't remove all impurities. It also doesn't control the freezing process, so the ice will still become cloudy.

Using distilled water: While distilling water removes more impurities than boiling, distilled water still freezes from the outside in, concentrating any remaining impurities or air bubbles in the center, again resulting in cloudy ice.

Using filtered or tap water: Filtering the water or using tap water also doesn't stop the impurities from concentrating during the conventional freezing process.

What actually works

As it turns out, it's not the water quality that guarantees clear ice. It's all about how you freeze it. The main technique for successfully making clear ice is called "directional freezing."

Directional freezing is simply the process of forcing water to freeze in a single direction instead of from all sides at once, like it does in a regular ice cube tray.

This way, the impurities and air will be forced to the opposite side from where the freezing starts, leaving the ice clear except for a small cloudy section.

In practice, this means insulating the sides of the ice container so that the water freezes in one direction, typically from the top down. This is because heat transfer and phase transition from liquid to solid happens faster through the exposed top than the insulated sides.

Part 2

How to make clear ice at home

The simplest way to have a go at directional freezing at home is to use an insulated container—you can use a really small cooler (that is, an "esky"), an insulated mug or even a commercially available insulated ice cube tray designed for making clear ice at home.

Fill the insulated container with water and place it in the freezer, then check on it periodically.

Once all the impurities and air bubbles are concentrated in a single cloudy area at the bottom, you can either pour away this water before it's fully frozen through, or let the block freeze solid and then cut off the cloudy portion with a large serrated knife, then cut the ice into cubes for your drinks.

If using a commercial clear ice tray, it will likely come with instructions on how to get rid of the cloudy portion so you can enjoy the sparkling clear ice.

How do I make clear ice at home? A food scientist shares easy tips

Author: Paulomi (Polly) Burey

The gut bacteria that put the brakes on weight gain in mice

The gut bacterium Turicibacter reduces weight gain and improves metabolic health in mice on a high-fat diet by producing fatty molecules that lower ceramide levels. Obese individuals tend to have less Turicibacter, suggesting a potential role in human weight regulation. Turicibacter’s effects depend on dietary fat, indicating a feedback loop between diet and gut microbiota.

The gut microbiome is intimately linked to human health and weight. Differences in the gut microbiome—the bacteria and fungi in the gut—are associated with obesity and weight gain, raising the possibility that changing the microbiome could improve health. But any given person's gut contains hundreds of different microbial species, making it difficult to tell which species could help.

Now, new research has identified a specific type of gut bacteria, called Turicibacter, that improves metabolic health and reduces weight gain in mice on a high-fat diet.

People with obesity tend to have less Turicibacter, suggesting that the microbe may promote healthy weight in humans as well. The results could lead to new ways to control weight by adjusting gut bacteria.

The results are published in Cell Metabolism.

The researchers found that a rod-shaped bacterium called Turicibacter could single-handedly reduce blood sugar, levels of fat in the blood, and weight gain for mice on a high-fat diet.

Turicibacter appears to promote metabolic health by producing fatty molecules that are absorbed by the small intestine. When the researchers added purified Turibactor fats to a high-fat diet, they had the same weight-controlling effects as Turicibacter itself.

They don't yet know which fatty molecules are the important part—the bacterium produces thousands of different fats, in what Klag describes as a "lipid soup"—but they hope to narrow down on the most important molecules in future work for potential therapeutic use.

Turicibacter appears to improve metabolic health by affecting how the host produces a fatty molecule called ceramides, the researchers found.

 The fats produced by Turicibacter are able to keep ceramide levels low, even for mice on a high-fat diet.

Turicibacter levels are themselves affected by how much fat the host eats, the researchers discovered. The bacterium won't grow if there's too much fat in its environment, so mice fed a high-fat diet will lose Turicibacter from their gut microbiome unless their diet is regularly supplemented with the microbe.

The results point to a complex feedback loop, in which a fatty diet inhibits Turicibacter and fats produced by Turicibacter improve how the host responds to dietary fats.

Kendra Klag et al, Dietary fat disrupts a commensal-host lipid network that promotes metabolic health, Cell Metabolism (2025). DOI: 10.1016/j.cmet.2025.10.007

With every extinction, we lose not just a species but a treasure trove of knowledge

Extinction results in the irreversible loss of unique scientific knowledge, cultural traditions, and spiritual connections associated with each species. Current extinction rates, driven mainly by human activities, far exceed natural background levels, threatening up to 1 million species this century. These losses diminish biodiversity, erode cultural and spiritual heritage, and reduce opportunities for future discoveries.

Study shows tooth loss, not low-protein intake, drives memory decline in aging mice
Tooth loss in aging mice leads to significant memory decline and increased markers of brain cell death, independent of dietary protein intake. Reduced chewing, rather than low-protein diet, promotes inflammation and neuronal loss in hippocampal regions critical for memory, highlighting a direct link between oral health and cognitive function.

Tooth loss doesn't just make eating harder, it may also make thinking more challenging. A new study shows that aging mice missing their molars experience measurable cognitive decline, even when their nutrition remains perfectly intact.

The study examined whether tooth loss itself, independent of nutritional deficiency such as a low-protein diet, can cause cognitive decline in male mice.

To explore how chewing ability and nutrition jointly influence the brain, the research team used aging-prone male mice and assigned them to one of four conditions: a normal-protein diet with no tooth extraction, a low-protein diet with no extraction, molar extraction with a normal-protein diet, and molar extraction with a low-protein diet.

After six months, the mice underwent behavioral tests and detailed analyses of their brain tissue for markers of inflammation, neuronal loss, and cell death–related gene expression.

The results were striking: mice that lost their molars showed significant memory decline even though they received the same diet as the control groups.

This suggests that reduced masticatory stimulation, not dietary protein intake, contributes to cognitive deterioration. It is surprising that a peripheral event in the mouth can so profoundly affect the central nervous system.

Brain tissue analysis supported these behavioral findings. The results showed no interaction effect between tooth loss and low-protein diet on the levels of the Bax/Bcl-2 mRNA ratio, a marker representing cell death versus survival.

Instead, tooth loss alone significantly increased this ratio, indicating a shift toward pro-apoptotic, or cell death–promoting, activity in the brain. Losing teeth caused inflammation and cell loss in the CA1 and dentate gyrus regions of the hippocampus—areas essential for memory formation and storage.

Meanwhile, the effects of a low-protein diet were limited to the CA3 region, which plays a role in pattern completion. These findings suggest that a reduction in chewing induces pro–cell death pathways in the brain.

This study adds to growing evidence that oral health is deeply connected to brain health, and that protecting one's chewing ability may be a simple but powerful strategy for preserving cognitive function later in life.

Rie Hatakeyama et al, Tooth loss induces cognitive decline independent of low-protein diet intake in male mice, Archives of Oral Biology (2025). DOI: 10.1016/j.archoralbio.2025.106421

New sprayable powder forms instant gel barrier to stop severe bleeding in seconds

A sprayable powder hemostatic agent rapidly forms a hydrogel barrier within one second upon contact with blood, effectively stopping severe bleeding, including from deep or irregular wounds. Composed of biocompatible natural materials, it demonstrates high absorption (725%), strong adhesion (>40 kPa), low hemolysis (<3%), high cell viability (>99%), and antibacterial properties (99.9%).

Youngju Son et al, An Ionic Gelation Powder for Ultrafast Hemostasis and Accelerated Wound Healing, Advanced Functional Materials (2025). DOI: 10.1002/adfm.202523910

'Don't use them': Tanning beds triple skin cancer risk, study finds

Tanning bed use is associated with nearly a threefold increase in melanoma risk, with users developing more DNA mutations in skin cells, particularly melanocytes. Melanomas in tanning bed users often appear on body areas usually shielded from sunlight. Over 80% of common melanomas are linked to ultraviolet radiation, including that from tanning beds.

Pedram Gerami et al, Molecular effects of indoor tanning, Science Advances (2025). DOI: 10.1126/sciadv.ady4878. www.science.org/doi/10.1126/sciadv.ady4878

Clouds are vital to life—but many are becoming wispy ghosts. Here's how to see the changes above us
Cloud cover, especially highly reflective clouds near the equator, is steadily declining by 1.5–3% per decade, reducing Earth's ability to reflect solar radiation and increasing heat retention. This shift alters rainfall patterns and climate stability, with the loss often unnoticed. Clouds play a crucial role in moderating temperature and sustaining life, making their decline a significant concern.

--

skies that feel hollowed out, clouds that look like they have lost their conviction. I think of them as ghost clouds. Not quite absent, but not fully there. These wispy formations drift unmoored from the systems that once gave them coherence. Too thin to reflect sunlight, too fragmented to produce rain, too sluggish to stir up wind, they give the illusion of a cloud without its function.

Clouds are vital to life – but many are becoming wispy ghosts. Here...

Traffic Has a Curious Effect on The Atmosphere's Electric Field, Study Shows

Detailed measurements collected in metropolitan Tel Aviv, Israel, have revealed how the ebb and flow of traffic throughout the week affects the electric field generated by Earth's atmosphere.

A number of specific pollutants were tracked, including gases and particles from car exhaust and tire wear, and additional compounds formed in chemical reactions with gases in the atmosphere.

The atmospheric electric field is the result of natural differences in charge between the surface and upper atmosphere, powered largely by the swirl of currents that form in thunderstorms.

A number of factors influence this planetary circuit, including fluctuations in local weather and air pollution. 

The data showed that traffic pollution in Tel Aviv has an immediate impact on the atmospheric electric field in the region, with both NOx gases and vehicle congestion peaking at the same times (the rush hours at the start and end of the working day).

There was also an association between PM2.5 particles and the electric field, though this was delayed by around two-and-a-half hours. The researchers put this down to different particle size, chemical composition, and lifetime in the atmosphere.

The team reports a noticeable weekend effect as well, with significant drops in traffic pollution corresponding with a weakening of the electrical field. That's further confirmation that the two are indeed linked.

What they observed is a direct physical link between emission peaks and electrical variability.

Nitrogen oxides reduce atmospheric conductivity very quickly, so the electric field responds almost instantaneously during traffic rush hours.

The reason behind the effect is ions: the charged particles in the air. Pollutants can capture these ions, reducing the conductivity of the atmospheric electric field, which then triggers a compensatory effect where the electric field gets stronger.

These changes aren't dangerous, and nor is the electric field itself .

Effects of urban air pollution on the fair-weather electric field i...

Ancient African bedrock reveals the violent beginnings of life on our blue planet

Ancient bedrock from the Makhonjwa Mountains reveals that early Earth featured extensive oceans, intense volcanic activity, and a hostile atmosphere rich in methane and CO2 but lacking oxygen. Life began as anaerobic microbes near undersea vents, thriving despite frequent volcanic eruptions, earthquakes, and asteroid impacts. Plate tectonics and a stable climate enabled Earth to remain habitable and blue.

The Oldest Rocks on Earth | Columbia University Press

Ancient African bedrock reveals the violent beginnings of life on o...

Evidence of upright walking found in 7-million-year-old Sahelanthropus fossils

Analysis of Sahelanthropus tchadensis fossils using 3D methods identified features unique to bipedal hominins, including a femoral tubercle, femoral antetorsion, and gluteal muscle attachments. These findings indicate that this seven-million-year-old species was adapted for upright walking, making it the earliest known bipedal hominin.

The analysis revealed three features that point to bipedalism in Sahelanthropus:

The presence of a femoral tubercle, which provides attachment for the iliofemoral ligament linking the pelvis to the femur and has so far been identified only in hominins

A natural twist, specifically within the range of hominins, in the femur—or femoral antetorsion—that helps legs to point forward, thereby aiding walking.

The presence, drawn from the 3D analysis, of gluteal, or butt, muscles similar to those in early hominins that keep hips stable and aid in standing, walking, and running.

Scott Williams, Earliest evidence of hominin bipedalism in Sahelanthropus tchadensis, Science Advances (2026). DOI: 10.1126/sciadv.adv0130. www.science.org/doi/10.1126/sciadv.adv0130

Two white-blooded fish, two paths: Icefish and noodlefish independently lose red blood cell function

Both Antarctic icefish and Asian noodlefish independently evolved to lack hemoglobin and red blood cells, resulting in white blood. Icefish survive in cold, oxygen-rich waters by dissolving oxygen directly in their blood, while noodlefish, living in warmer waters, lost myoglobin and have nonfunctional hemoglobin genes, likely aided by their short, juvenile-like life span. These findings highlight distinct evolutionary paths to similar physiological outcomes.

 Yu-Long Li et al, Independent evolutionary deterioration of the oxygen-transport system in Asian noodlefishes and Antarctic icefishes, Current Biology (2025). DOI: 10.1016/j.cub.2025.05.050

Bacteria reveal second 'shutdown mode' for surviving antibiotic treatment
Bacteria can survive antibiotic treatment through two distinct growth-arrest states: a regulated, protective dormancy and a disrupted, dysregulated arrest marked by impaired membrane stability. This duality explains conflicting observations of antibiotic persistence and suggests that targeting each state differently could improve treatment effectiveness and reduce infection relapse.

A new study reveals that bacteria can survive antibiotic treatment through two fundamentally different "shutdown modes," not just the classic idea of dormancy. The paper is published in the journal Science Advances.

The researchers show that some cells enter a regulated, protective growth arrest, a controlled dormant state that shields them from antibiotics, while others survive in a disrupted, dysregulated growth arrest, a malfunctioning state marked by vulnerabilities, especially impaired cell membrane stability. This distinction is important because antibiotic persistence is a major cause of treatment failure and relapsing infections even when bacteria are not genetically resistant, and it has remained scientifically confusing for years, with studies reporting conflicting results.

By demonstrating that persistence can come from two distinct biological states, the work helps explain those contradictions and provides a practical path forward: different persister types may require different treatment strategies, making it possible to design more effective therapies that prevent infections from coming back.

For years, persistence has largely been blamed on bacteria that shut down and lie dormant, essentially going into a kind of sleep that protects them from antibiotics designed to target active growth. But new research reveals that this explanation tells only part of the story.

The study shows that high survival under antibiotics can originate from two fundamentally different growth-arrest states, and they are not just variations of the same "sleeping" behavior. One is a controlled, regulated shutdown, the classic dormancy model. The other is something entirely different: a disrupted, dysregulated arrest, where bacteria survive not by protective calm but by entering a malfunctioning state with distinct vulnerabilities.

Part 1

Two 'survival modes' and why they matter
The researchers identified two archetypes of growth arrest that can both lead to persistence, but for very different reasons:

Regulated growth arrest: a protected dormant state. In this mode, bacteria intentionally slow down and enter a stable, defended condition. These cells are harder to kill because many antibiotics rely on bacterial growth to be effective.

Disrupted growth arrest: survival through breakdown. In the second mode, bacteria enter a dysregulated and disrupted state. This is not a planned shutdown, but a loss of normal cellular control. These bacteria show a broad impairment in membrane homeostasis, a core function needed to maintain the integrity of the cell. That weakness could become a key treatment target.
Antibiotic persistence plays a role in recurring infections across a wide range of settings, from chronic urinary tract infections to infections tied to medical implants. Yet despite intense research, scientists have struggled to agree on a single mechanism explaining why persister cells survive. Different experiments have produced conflicting results about what persisters look like and how they behave.

This study offers an explanation: researchers may have been observing different types of growth-arrested bacteria without recognizing they were distinct.

By separating persistence into two different physiological states, the findings suggest a future where treatments could be tailored, targeting dormant persisters one way, and disrupted persisters another.
How the researchers saw what others missed
The team combined mathematical modeling with several high-resolution experimental tools, including:

Transcriptomics, to measure how bacterial gene expression shifts under stress
Microcalorimetry, to track metabolic changes through tiny heat signals
Microfluidics, allowing scientists to observe single bacterial cells under controlled conditions
Together, these approaches revealed clear biological signatures distinguishing regulated growth arrest from disrupted growth arrest, along with the specific vulnerabilities of the disrupted state.

Adi Rotem et al, Differentiation between regulated and disrupted growth-arrests allows tailoring of effective treatments for antibiotic persistence, Science Advances (2026). DOI: 10.1126/sciadv.adt6577. www.science.org/doi/10.1126/sciadv.adt6577

Part 2

Tumor bacteria linked to immunotherapy resistance in head and neck cancer

Researchers have discovered that bacteria inside cancerous tumors may be key to understanding why immunotherapy works for some patients but not others.
Elevated bacterial levels within head and neck squamous cell carcinoma tumors suppress immune responses and contribute to resistance against immunotherapy. These bacteria attract neutrophils, which can inhibit the immune activity required for effective treatment. Reducing tumor bacteria with antibiotics may enhance immunotherapy efficacy, suggesting new avenues for patient selection and targeted interventions.

These studies shift the focus of immunotherapy resistance research beyond tumor genetics to unexpected factors like the tumor microbiome.

By identifying bacteria as a key barrier to treatment, we're opening the door to new strategies for patient selection and targeted antibiotic therapies, potentially improving outcomes for those who don't benefit from immunotherapy, the researchers say.

The research confirmed that patients with high tumor bacteria levels had poorer outcomes with immunotherapy compared to standard chemoradiotherapy.

Together, the two studies showed that elevated bacteria levels in tumors attract neutrophils, white blood cells that fight infection. While neutrophils are essential for combating bacterial infections, in cancer they can suppress the immune system needed for immunotherapy to work effectively.

These findings lay the foundation for future research on why bacteria are attracted to tumors and how to modify them to improve treatment.

1. Tumor ecosystem and microbiome features associated with efficacy and resistance to avelumab plus chemoradiotherapy in head and neck cancer, Nature Cancer (2025). DOI: 10.1038/s43018-025-01068-0

2. Nature Cancer (2025). www.nature.com/articles/s43018-025-01067-1

Assisted reproductive technology associated with higher risk of childhood atopic diseases

Researchers  report higher risks of atopic disease among children conceived via assisted reproductive technology compared to those conceived naturally.

Assisted reproductive technology use has increased, with estimates placing assisted reproductive technology at 1% to 4% of births, especially in high-income societies, alongside wider use of embryo transfer.

Atopic disease covers three conditions; asthma, allergic rhinitis, and atopic dermatitis. Atopic diseases are believed to be influenced by genetic factors and environmental triggers, with developmental origins of health and disease theory proposing that fetal-stage factors can program changes in organ and tissue structure and function.

In the study, "Atopic Disease Development in Offspring Conceived via Assisted Reproductive Technology," published in JAMA Network Open, researchers conducted a retrospective, population-based cohort analysis to investigate whether conception via assisted reproductive technology was associated with atopic disease development in offspring.

Data came from a pool of 23.5 million people in Taiwan through Taiwan's National Health Insurance Research Database, Assisted Reproduction Database, and the Maternal and Child Health Database.

Assisted reproductive technology included procedures such as in vitro fertilization and embryo transfer, intracytoplasmic sperm injection, gamete intrafallopian transfer, zygote intrafallopian transfer, and tubal embryo transfer.

Part 1

Cohort groups included 13,957 children conceived via assisted reproductive technology and 55,828 children conceived naturally after 1:4 matching by maternal age, neonatal sex, and birth month.

Asthma, allergic rhinitis, and atopic dermatitis were analyzed and reported individually, allowing a child to receive one, two, or all three diagnoses during follow-up. Mean follow-up for asthma measured 7.99 years in the assisted reproductive technology group and 8.41 years in the control group, with allergic rhinitis at 5.79 and 6.34 years, and atopic dermatitis at 7.34 and 7.62 years.
Intracytoplasmic sperm injection use showed no statistically significant differences in risk estimates across the three outcomes. Adjusted hazard ratios measured 1.04 for asthma, 0.99 for allergic rhinitis, and 1.04 for atopic dermatitis.

Fresh embryo transfer carried a higher allergic rhinitis risk than frozen embryo transfer, with an adjusted hazard ratio of 1.12. Asthma showed no statistically significant difference between fresh and frozen embryo transfer, with an adjusted hazard ratio of 0.96, and atopic dermatitis showed no statistically significant difference, with an adjusted hazard ratio of 1.01.

Interaction testing showed no statistically significant interaction between intracytoplasmic sperm injection and embryo type for asthma, allergic rhinitis, or atopic dermatitis.
Researchers conclude that children conceived via assisted reproductive technology had a higher risk of developing asthma, allergic rhinitis, or atopic dermatitis than children conceived naturally. Findings supported an association between assisted reproductive technology conception and later atopic disease development across the outcomes evaluated.

Yao-Chi Hsieh et al, Atopic Disease Development in Offspring Conceived via Assisted Reproductive Technology, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.51690

Part 2

The (metabolic) 'cost of life': New method quantifies hidden energy costs of maintaining metabolic pathways
A new thermodynamic framework quantifies the hidden energetic costs required to maintain specific metabolic pathways and suppress alternatives, beyond direct metabolic energy use. This method ranks pathways by their maintenance and restriction costs, revealing that nature often selects the least dissipative routes, providing insights into the evolution and selection of metabolic processes.

There are "costs of life" that mechanical physics cannot calculate. A clear example is the energy required to keep specific biochemical processes active—such as those that make up photosynthesis, although the examples are countless—while preventing alternative processes from occurring.

In mechanics, no displacement implies zero work, and, put simply, there is no energetic cost for keeping things from happening. Yet careful stochastic thermodynamic calculations show that these costs do exist—and they are often quite significant.

A paper published in the Journal of Statistical Mechanics: Theory and Experiment (JSTAT) proposes a way to calculate these costs from a thermodynamic perspective and thus to offer a new tool for understanding the selection and evolution of metabolic pathways at the root of life.

When, in an ancient ocean, a handful of organic molecules formed an external boundary—the first cell membrane—a sharp distinction between an inside and an outside appeared for the first time.

From that moment on, that primordial system had to invest energy to maintain this compartmentalization and to select, among the many chemical reactions that could occur, only a few metabolic pathways capable of exploiting valuable substances taken from the "outside" and transforming them into new products. Life was born together with this effort of compartmentalization and choice.

Metabolic processes have a direct energetic cost, but they also require an "extra cost" to keep steering chemical flows into a preferred pathway rather than letting them disperse into all physically possible alternatives.

Part 1

Yet from the viewpoint of classical mechanics, compartmentalization and reaction selection—the "constraints" imposed at a system's boundaries—should have no cost at all, as they are treated as fixed external conditions that do not contribute to entropy production.
Researchers now developed a method to calculate these overlooked costs to rank the pathways. This allows researchers to assess their biological efficiency—valuable information for evolutionary studies exploring how life emerged on our planet.
devised a general method to estimate the thermodynamic costs of metabolic processes systematically. In their framework, the cell is imagined as a system crossed by a constant flow, where, for instance, one molecule (a nutrient) enters and another (a product or waste) exits.

Given the underlying chemistry, one can generate all chemically possible pathways that convert the input into the output. Each pathway has its own "thermodynamic cost." Instead of calculating energy in the classical sense, the method estimates how improbable it would be—in a world driven solely by spontaneous chemistry—to see the network (the set of molecules and reactions that convert input to output) behave in exactly that way.

This improbability has two components. The first is the maintenance cost, meaning how unlikely it is to sustain a constant flow through a certain pathway. The second is the restriction cost, which measures how unlikely it is to block all the alternative reactions in the network while keeping only the pathway of interest active.

The calculated improbability represents the cost of that process, which can then be used to classify metabolic pathways according to how "expensive" it is for the cell to keep one pathway active and silence the others.
Part 2

In nature we usually see that one process is favoured over many. Why is this?

It's true, but in biological systems, catalysis often intervenes—the action of facilitating molecules, enzymes—which accelerate reactions and make them less costly, achieving the same effect as having multiple pathways in parallel. This evolutionary choice happens because maintaining many pathways can have other drawbacks, such as producing many potentially toxic molecules.

 Thermodynamic ranking of pathways in reaction networks, Journal of Statistical Mechanics Theory and Experiment (2025). DOI: 10.1088/1742-5468/ae22eb.

Part 3

**

Orange pigments in birds and human redheads prevent cellular damage, study shows

A pigment that makes feathers and hair orange helps prevent cellular damage by removing excess cysteine from cells. Pheomelanin is an orange-to-red pigment that is built with the amino acid cysteine and found in human red hair and fair skin, as well as in bird feathers. Previous research has shown that pheomelanin is associated with increased melanoma risk, raising questions about why evolution has maintained genetic variants that promote pheomelanin production.

Published in PNAS Nexus, researchers studied 65 adult zebra finches divided into treatment and control groups. In the treatment group, male zebra finches received dietary cysteine and ML349, a drug that blocks pheomelanin synthesis.

Male birds treated with both cysteine and ML349 showed increased oxidative damage in blood plasma compared to males receiving only cysteine, when the authors controlled for overall expression of the regulator of antioxidants by melanocytes. Female birds, which do not produce pheomelanin, tended to show increased oxidative damage when treated with cysteine alone as compared to female controls.

According to the authors, pheomelanin synthesis helps maintain cysteine homeostasis by converting excess cysteine into inert pigment, which may explain why pheomelanin-promoting genetic variants persist despite being associated with increased melanoma risk.

 Ismael Galván et al, MC1R depalmitoylation inhibition reveals a physiological role for pheomelanin, PNAS Nexus (2026). DOI: 10.1093/pnasnexus/pgaf391

Vitamin C may help protect fertility from a harmful environmental chemical

Exposure to potassium perchlorate impairs sperm production and damages testes in a fish model, indicating potential reproductive risks. Co-administration of vitamin C reduces this damage and improves fertility, likely by counteracting oxidative stress. These results suggest vitamin C may help protect reproductive health from certain environmental contaminants.

Sourav Chakraborty et al, Vitamin C Mitigates Potassium Perchlorate Exposure-Induced Disruption of Spermatogenesis in Medaka, Environmental Science & Technology (2025). DOI: 10.1021/acs.est.5c09514

Diet may influence tinnitus risk in women

Diet may influence the risk of women developing tinnitus, according to a study published online Dec. 17 in the American Journal of Epidemiology.
Higher fruit intake is associated with reduced risk of developing persistent tinnitus in women, while greater consumption of whole grains, legumes, and sugar-sweetened beverages is linked to increased risk. Overall healthy diet patterns did not consistently affect tinnitus risk. These associations remained after accounting for lifetime noise exposure.

This study provides compelling evidence that dietary intake can influence the development of persistent tinnitus.

Sharon G Curhan et al, Longitudinal Study of Dietary Intake and Risk of Persistent Tinnitus in Two Large Independent Cohorts of Women, American Journal of Epidemiology (2025). DOI: 10.1093/aje/kwaf277

Jellyfish don’t need brains to sleep!

Jellyfish sleep like humans — even though they don’t have brains

Jellyfish and sea anemones have neurons, but no brains — and yet they still seem to sleep in ways strikingly similar to humans. The findings bolster a theory that sleep evolved — before centralized nervous systems — to repair DNA damage that builds up in individual nerve cells while animals are awake. Neurons are very precious. They don’t divide, so you need to keep them intact.

The findings bolster a theory that sleep evolved, at least in part, to protect the DNA in individual nerve cells, helping to repair damage that builds up while animals are awake.

Sleep is a risky state for animals. It leaves them vulnerable to predators and environmental hazards, and it cuts into time that could otherwise be spent foraging, mating or caring for offspring. Scientists broadly agree that sleep must serve a fundamental biological function, because evolution has preserved it across all animals with nervous systems studied so far.

These results suggest that DNA damage and cellular stress in simple nerve nets may have driven the evolution of sleep.

https://www.nature.com/articles/s41467-025-67400-5

https://www.nature.com/articles/d41586-026-00044-7?utm_source=Live+...

Restoring mitochondria shows promise for treating chronic nerve pain

For millions living with nerve pain, even a light touch can feel unbearable. Scientists have long suspected that damaged nerve cells falter because their energy factories known as mitochondria don't function properly.

Now, research published in Nature suggests a way forward: supplying healthy mitochondria to struggling nerve cells.

Using human tissue and mouse models, researchers found that replenishing mitochondria significantly reduced pain tied to diabetic neuropathy and chemotherapy-induced nerve damage. In some cases, the relief lasted up to 48 hours. By giving damaged nerves fresh mitochondria—or helping them make more of their own—we can reduce inflammation and support healing, say the scientists. Their findings build on growing evidence that cells can swap mitochondria, a process that scientists are beginning to recognize as a built-in support system that may affect many conditions including obesity, cancer, stroke, and chronic pain.

When this mitochondrial handoff is disrupted, nerve fibers begin to degenerate—triggering pain, tingling and numbness, often in the hands and feet, the distal ends of the nerve fibers.

By sharing energy reserves, satellite glial cells may help keep neurons out of pain.

When this energy transfer was boosted, pain behaviors in mice dropped by as much as 50%, the study showed.

Researchers also tried a more direct approach. Injecting isolated mitochondria—whether from humans or mice—directly into the dorsal root ganglia, a cluster of nerve cells that send messages to the brain, produced similar results, but only when the donor mitochondria were healthy; samples from people with diabetes had no effect.

The team also identified a protein, MYO10, as essential for forming the nanotubes that enable the mitochondrial transfer.

Instead of masking symptoms, the approach could fix what the team sees as the root problem—restoring the energy flow that keeps nerve cells healthy and resilient.

Ru-Rong Ji, Mitochondrial transfer from glia to neurons protects against peripheral neuropathy, Nature (2026). DOI: 10.1038/s41586-025-09896-x. www.nature.com/articles/s41586-025-09896-x

The work highlights a previously undocumented role for satellite glial cells, which appear to deliver mitochondria to sensory neurons through tiny channels called tunneling nanotubes.

Oil residues can travel over 5,000 miles on ocean debris, study finds

Oil residues can adhere to ocean debris such as plastic, glass, and rubber, enabling them to travel over 5,200 miles across the Atlantic. Chemical analyses and ocean current modeling linked oily debris found in Florida to a 2019 oil spill off Brazil, demonstrating that plastics can act as long-distance carriers for oil pollution, extending the environmental impact of oil spills.

"Long-Range Transport of Oil by Marine Plastic Debris: Evidence from an 8500 km Journey," Environmental Science & Technology (2026). DOI: 10.1021/acs.est.5c14571

Dark matter and neutrinos may interact, challenging standard model of the universe

Scientists are a step closer to solving one of the universe's biggest mysteries as new research finds evidence that two of its least understood components may be interacting, offering a rare window into the darkest recesses of the cosmos.

The  findings relate to the relationship between dark matter, the mysterious, invisible substance that makes up about 85% of the matter in the universe, and neutrinos, one of the most fundamental and elusive subatomic particles. Scientists have overwhelming indirect evidence for the existence of dark matter, while neutrinos, though invisible and with an extremely small mass, have been observed using huge underground detectors.

The standard model of cosmology (Lambda-CDM), with its origins in Einstein's general theory of relativity, posits that dark matter and neutrinos exist independently and do not interact with one another.

New new research published in Nature Astronomy casts doubt on this theory, challenging the long-standing cosmological model. The research detects signs that these elusive cosmic components may interact, offering a rare glimpse into parts of the universe we can't see or easily detect.

By combining data from different eras, scientists have found evidence of interactions between dark matter and neutrinos that could have affected the way cosmic structures, such as galaxies, formed over time.

Data regarding the early universe comes from two main sources: the highly sensitive ground-based Atacama Cosmology Telescope (ACT), and the Planck Telescope, a space observatory operated by the European Space Agency (ESA) from 2009 to 2013. Both instruments were specifically designed to study the faint afterglow of the Big Bang.

Lei Zu et al, A solution to the S₈ tension through neutrino–dark matter interactions, Nature Astronomy (2026). DOI: 10.1038/s41550-025-02733-1

Eating more food preservatives linked to higher risk of type 2 diabetes

Higher intake of food preservatives, including both non-antioxidant and antioxidant additives, is associated with an increased risk of type 2 diabetes, with incidence rates rising by 47%, 49%, and 40% respectively for higher consumption groups. Twelve commonly used preservatives, such as potassium sorbate (E202) and citric acid (E330), showed significant associations with elevated diabetes risk.

Higher consumption of food preservatives, widely used in industrially processed foods and beverages to extend their shelf life, has been linked to an increased risk of type 2 diabetes.

Preservatives belong to the family of food additives and are widely used by the food industry worldwide. Of the three and a half million foods and beverages listed in the Open Food Facts World database in 2024, more than 700,000 contain at least one of these substances.

Additives with preservative properties have been grouped into two categories in the work carried out by Inserm researchers: non-antioxidants (which inhibit microbial growth or slow down the chemical changes that lead to food spoilage) and antioxidants (which delay or prevent food spoilage by eliminating or limiting oxygen levels in packaging).

On packaging, they generally correspond to European codes between E200 and E299 (for preservatives in the strict sense) and between E300 and E399 (for antioxidant additives).

Experimental studies have suggested that certain preservatives may damage cells and DNA and have adverse effects on metabolism.

A research team set out to examine the links between exposure to these preservatives and type 2 diabetes. The team drew on data provided by more than 100,000 French adults.

Analyses of data showed higher consumption of preservative additives overall, non-antioxidant preservatives and antioxidant additives was associated with an increased incidence of type 2 diabetes, by 47%, 49% and 40% respectively, compared to the lowest levels of consumption.

Of the 17 preservatives studied individually, higher consumption of 12 of them was associated with an increased risk of type 2 diabetes: widely used non-antioxidant food preservatives (potassium sorbate (E202), potassium metabisulfite (E224), sodium nitrite (E250), acetic acid (E260), sodium acetates (E262) and calcium propionate (E282)) and antioxidant additives (sodium ascorbate (E301), alpha-tocopherol (E307), sodium erythorbate (E316), citric acid (E330), phosphoric acid (E338) and rosemary extracts (E392)).

This is the first study in the world on the links between preservative additives and the incidence of type 2 diabetes. Although the results need to be confirmed, they are consistent with experimental data suggesting the harmful effects of several of these compounds.

Associations between preservative food additives and type 2 diabetes incidence in the NutriNet-Santé prospective cohort, Nature Communications (2026). DOI: 10.1038/s41467-025-67360-w

Your genes determine how fast your DNA mutates with age, study shows

Analysis of genetic data from over 900,000 individuals shows that common DNA repeats in blood cells expand with age, with inherited variants at 29 genetic locations modifying expansion rates by up to four-fold. Some DNA repair genes have opposite effects on different repeats. Expansion in the GLS gene is linked to increased risk of kidney and liver disease, highlighting new potential biomarkers and therapeutic targets.

An analysis of genetic data from over 900,000 people shows that certain stretches of DNA, made up of short sequences repeated over and over, become longer and more unstable as we age. The study found that common genetic variants can speed up or slow down this process by up to four-fold, and that certain expanded sequences are linked to serious diseases including kidney failure and liver disease.

More than 60 inherited disorders are caused by expanded DNA repeats: repetitive genetic sequences that grow longer over time. These include devastating conditions like Huntington's disease, myotonic dystrophy, and certain forms of ALS.

Most people carry DNA repeats that gradually expand throughout their lives.

This study demonstrates that DNA repeat expansion is far more widespread than previously recognized and identifies dozens of genes that regulate this process, opening new avenues for developing treatments that could slow disease progression.

Margaux Hujoel, Insights into DNA repeat expansions among 900,000 biobank participants, Nature (2026). DOI: 10.1038/s41586-025-09886-z. www.nature.com/articles/s41586-025-09886-z