Scientists recruit bed bugs as crime scene sleuths

Tropical bed bugs can retain human DNA for up to 45 days after feeding, enabling recovery of phenotypic traits such as gender, eye, hair, and skin color using STR and SNP markers. Their limited mobility and tendency to remain hidden make them valuable forensic tools at crime scenes, though their usefulness is restricted to recent events within a 45-day window.

Reprogrammed Human Stomach Organoids Secrete Insulin

Transplanting human gastric organoids engineered to release insulin in diabetic mice reduced hyperglycemia, offering a therapeutic avenue for type 1 diabetes.

An estimated 9.5 million people all over the world live with type 1 diabetes, wherein the beta cells in their pancreas cannot produce enough insulin to keep blood glucose in check. In the long run, elevated glucose can damage organs such as the kidneys, heart, and eyes. Over the past few decades, scientists have been studying how to generate functional insulin-secreting cells which could be transplanted into patients.

Now, researchers engineered human stomach organoids to secrete insulin. Transplanting these into diabetic mice reduced hyperglycemia. Their findings, published today in Stem Cell Reports, could help develop technologies to engineer a person’s own insulin-secreting cells for diabetes treatment.

Lu J, et al. Modeling in vivo induction of gastric insulin-secreting cells using.... Stem Cell Rep. 2025. 

Switching immune cells to 'night mode' could limit damage after a heart attack

Treating mice with a drug that inhabits the neutrophil clock reduced the amount of myocardial tissue damage after a heart attack and helped to preserve heart function over the following days and weeks.

The drug, known as ATI2341, targets a receptor protein on the surface of neutrophils and switches the cells into a less active mode usually only seen at night.

In their active, daytime mode, neutrophils accumulate around the edge of the initial wound caused by a heart attack, where they are poised to damage neighboring healthy cardiac tissue and extend the size of the injury. In night mode, however, neutrophils accumulate in the center of the initial wound, well away from the surrounding, healthy tissue.

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ATI2341 also protected mice from several other types of neutrophil-induced tissue damage but, crucially, did not impair the animals' ability to fend off bacterial and fungal infections.

Aroca-Crevillén et al. A circadian checkpoint relocates neutrophils to minimize injury, Journal of Experimental Medicine (2025). DOI: 10.1084/jem.20250240

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'Self-activation' is part of the success strategy of parasitic weeds 

Certain parasitic weeds can autonomously activate their feeding organs (haustoria) before encountering a host by producing and releasing specific substances from their seeds. This early self-activation enables rapid and effective host attachment, contributing to their persistence and difficulty of control in agriculture. The process is influenced by compounds from both host and non-host seeds, and targeting these early signaling pathways may offer new weed management strategies.

Guillaume Brun et al, Seed metabolites headstart haustoriogenesis and potentiate aggressiveness of parasitic weeds, Science Advances (2025). DOI: 10.1126/sciadv.aea1449

Fat tissue around the heart may contribute to greater heart injury after a heart attack 

Greater epicardial adipose tissue (EAT) volume, measured by cardiovascular imaging, is independently associated with larger myocardial infarct size and greater area at risk after myocardial infarction, though not with reduced left ventricular ejection fraction. Non-invasive EAT quantification may enhance cardiovascular risk assessment beyond traditional factors.

Epicardial adipose tissue (EAT) is the layer of fat between the myocardium and the lining of the heart, directly surrounding the coronary arteries. Under certain pathological conditions, EAT releases inflammatory mediators leading to myocardial infiltration and constrictive effects. Over time, adverse remodeling of the myocardium can occur.

Researchers have now shown that patients with increased EAT volume exhibited greater acute myocardial injury following MI.

https://www.escardio.org/The-ESC/Press-Office/Press-releases/fat-ti...

Abdominal obesity and muscle loss increase the risk of death by 83% after age 50, study finds

Tattoos might put the immune system at risk

 Studies in mice suggest that the pigment used in tattoos accumulates in the lymph nodes and might affect immune responses. Researchers found that ink remained in the lymph nodes for months and had varying effects: it weakened the animals’ response to a COVID vaccine but increased the reaction to an influenza vaccine.

https://www.pnas.org/doi/10.1073/pnas.2510392122

Space debris poses growing threat, but new study suggests cleanup is feasible

So in his latest study, titled "Space Logistics Analysis and Incentive Design for Commercialization of Orbital Debris Remediation" and published in the Journal of Spacecraft and Rockets, researchers investigated ways to create commercial opportunities for space operators and debris remediators to clean up dangerous junk.

The study analyzed three possible scenarios of debris cleanup—controlled reentry back to Earth, uncontrolled reentry back to Earth, and recycling in space. All three methods would require a space debris remediation satellite - a vehicle designed to capture and remove space junk from orbit. 

In the uncontrolled re-entry scenario, the remediation service vehicle would grab the debris from the orbit path it flies in and bring it down to about 350 kilometers away from Earth. The piece of debris would continue orbiting around our planet until it entered the atmosphere and either burned or landed someplace.

It will either burn or drop somewhere on Earth, but we don't know where because it depends on the atmospheric drag it receives. This uncontrolled reentry method is the cheapest as the remediation vehicle doesn't have to fly long distances.

In the controlled reentry scenario, the remediation service vehicle would bring the debris much closer to Earth, down to about 50 kilometers.  Controlled reentry is more expensive because the servicer needs to bring the debris down closer to Earth and then fly up again to get the next piece of debris. That consumes more energy and more fuel than an uncontrolled reentry .

In the recycling scenario, the debris would be transported from its original orbit to a recycling center up in space. The transportation would require fuel, adding to the cost, but a lot of energy would also be saved by reusing aluminum, the metal commonly used in spacecraft, up in orbit rather than having to bring it up from Earth.

It takes about $1,500 per kilogram to launch anything from Earth to space.  . So if you don't have to launch from Earth, it's a benefit.

Space operators stand a lot to gain from debris removal. Their satellites can operate more safely and efficiently, so they save money on fuel and operations, since they don't have to make extra maneuvers to avoid collisions.

Asaad Abdul-Hamid et al, Space Logistics Analysis and Incentive Design for Commercialization of Orbital Debris Remediation, Journal of Spacecraft and Rockets (2025). DOI: 10.2514/1.a36465

https://phys.org/news/2025-12-space-debris-poses-threat-cleanup.htm...

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Most normal matter in the universe isn't found in planets, stars or galaxies

Only about 9% of the universe’s normal (baryonic) matter is found in stars and cold gas within galaxies, while 76% resides in the intergalactic medium and 15% in galaxy halos. This distribution matches Big Bang predictions, confirming that most normal matter exists as diffuse gas between galaxies, not in visible structures. Dark matter and dark energy remain the dominant, poorly understood components.

Classical Indian dance inspires new ways to teach robots how to use their hands  

Analysis of Bharatanatyam dance gestures revealed a more versatile set of hand movement synergies than those found in natural grasps. These mudra-derived synergies enabled robots to replicate a wider range of hand motions, such as American Sign Language letters, more effectively. The findings support developing task-specific movement libraries for robotics and physical therapy applications.

Parthan Olikkal et al, Reconstructing hand gestures with synergies extracted from dance movements, Scientific Reports (2025). DOI: 10.1038/s41598-025-25563-7

For the first time, researchers observe how influenza viruses infect living cells 

 A novel microscopy technique enabled real-time, high-resolution observation of influenza virus entry into living cells. Findings show that cells actively participate in viral uptake by recruiting clathrin proteins and forming membrane pockets, rather than being passive targets. This method offers valuable insights for antiviral drug development and can be applied to study other viruses.

Aiko Yoshida et al, Enhanced visualization of influenza A virus entry into living cells using virus-view atomic force microscopy, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2500660122

Single enzyme failure found to drive neuron loss in dementia 

 Loss of function in the enzyme glutathione peroxidase 4 (GPX4) disrupts neuronal protection against ferroptosis, leading to neuron death and early-onset dementia. A specific GPX4 mutation impairs its ability to neutralize lipid peroxides at the cell membrane, triggering neurodegeneration. Inhibiting ferroptosis can slow this process in experimental models.

Svenja M. Lorenz et al, A fin-loop-like structure in GPX4 underlies neuroprotection from ferroptosis, Cell (2025). DOI: 10.1016/j.cell.2025.11.014

https://medicalxpress.com/news/2025-12-enzyme-failure-neuron-loss-d...

How volcanic eruptions set off a chain of events that brought the Black Death to Europe
Volcanic eruptions around 1345 triggered consecutive years of cooling, leading to crop failures and famine in southern Europe. To prevent starvation, Italian city states imported grain from the Black Sea, inadvertently introducing Yersinia pestis via infected fleas on ships. This sequence of climate, agricultural, and trade events enabled the Black Death's rapid spread across Europe.

'Brainquake' phenomenon links psychotic states to chaotic information flow

Deadly Asian floods are no fluke.

They're a climate warning, scientists say Southeast Asia is experiencing increasingly severe and unpredictable floods and storms, consistent with climate change projections. The region is warming nearly twice as fast as the global average, intensifying extreme weather events. Governments are struggling to prepare for and respond to these disasters, which are exacerbated by deforestation and unregulated development. Economic losses are substantial, while climate finance remains insufficient.
Climate patterns last year helped set the stage for 2025's extreme weather.Atmospheric levels of heat-trapping carbon dioxide jumped by the most on record in 2024. That "turbocharged" the climate, the United Nation's World Meteorological Organization says, resulting in more extreme weather.Asia is bearing the brunt of such changes, warming nearly twice as fast as the global average. Scientists agree that the intensity and frequency of extreme weather events are increasingWarmer ocean temperatures provide more energy for storms, making them stronger and wetter, while rising sea levels amplify storm surges While the total number of storms may not dramatically increase, their severity and unpredictability will What we're seeing in the region is dramatic and it's unfortunately a stark reminder of the consequences of the climate crisis, scientists conclude.
Source: News Agenices

Electric vehicle high-nickel batteries: Fundamental cause of performance degradation identified

Succinonitrile (CN₄), an electrolyte additive previously used to enhance stability in lithium-ion batteries, has been identified as a primary cause of rapid degradation in high-nickel batteries. CN₄ binds strongly to nickel ions, disrupting the cathode’s protective layer, causing structural damage, and accelerating performance loss.

Seung Hee Han et al, Unveiling Bidentate Nitrile-Driven Structural Degradation in High-Nickel Cathodes, ACS Energy Letters (2025). DOI: 10.1021/acsenergylett.5c02845

Ant brood signal deadly infection in altruistic self-sacrifice

Terminally ill ant pupae emit specific non-volatile odor signals that prompt worker ants to remove and disinfect them, preventing pathogen spread within the colony. This targeted signaling occurs only when infections are uncontrollable, ensuring colony health while minimizing unnecessary sacrifice, and parallels immune responses in multicellular organisms.

Sylvia Cremer, Altruistic disease signalling in ant colonies, Nature Communications (2025). DOI: 10.1038/s41467-025-66175-z. www.nature.com/articles/s41467-025-66175-z

Cancer cells keep their chromosomes intact to continue dividing relentlessly

Cancer cells maintain their ability to divide by using telomerase to repair chromosome ends (telomeres). An internal actin protein network in the nucleus helps telomerase access damaged telomeres, supporting cell survival even after chemotherapy-induced DNA damage. Targeting telomerase or this actin network could enhance chemotherapy effectiveness and reduce side effects.

Ashley Harman et al, Nuclear actin and DNA replication stress regulate telomere maintenance by telomerase, Nature Communications (2025). DOI: 10.1038/s41467-025-66506-0

Scientists call for greater focus on conserving whole ecosystems instead of charismatic species

Conservation programs are often too focused on a single charismatic species.

With many species worldwide experiencing population declines, there is an urgent need for conservation initiatives to support their recovery. However, this urgency, combined with insufficient scientific knowledge about endangered species, means that conservationists have often relied on oversimplified measures of success. For example, historical conservation efforts often focused on the abundance of a single charismatic species as a proxy for overall ecosystem health.

Researchers highlight three examples from China where oversimplified conservation priorities led to negative outcomes. The Chinese giant salamander (Andrias davidianus) is known as a "cryptic species," because it has multiple, genetically distinct populations that look identical to the naked eye.

Unaware of this, conservationists began a large-scale captive breeding and reintroduction program, which led to genetic mixing that threatened native populations. In the case of the crested Ibis (Nipponia nippon) and Père David's deer (Elaphurus davidianus), intensive captive breeding and release programs with limited suitable habitat have resulted in overcrowding, inbreeding and increased mortality.

Although well-intentioned, these initiatives have caused unforeseen issues for the ecosystem, and have often failed to improve the conservation status of the target species.

To avoid repeating these mistakes, the researchers advocate for a more nuanced approach to conservation, focused on creating balanced ecosystems, restoring habitats and minimizing human intervention. Although there has recently been more emphasis placed on protecting whole ecosystems, charismatic species conservation is still prevalent in the world.

Conservation programs that aim to preserve and restore ecosystem functions are a more effective use of limited resources, and are less likely to have unintended consequences, the researchers say. 

Shi H-T, et al. Are we over-conserving charismatic species? PLOS Biology (2025). DOI: 10.1371/journal.pbio.3003494

Ming Siang Lem et al, Ultrasonic pulse repetition rates triggering escape responses of a moth pest, Pest Management Science (2025). DOI: 10.1002/ps.70204

Cancer-promoting DNA circles hitchhike on chromosomes to spread to daughter cells

Extrachromosomal DNA circles (ecDNA) in cancer cells persist by attaching to chromosomes during cell division using specific retention elements, mimicking natural gene regulation mechanisms. Disrupting this attachment, such as by adding methyl groups to retention elements, leads to ecDNA loss and reduced cancer cell survival, highlighting a potential therapeutic target for cancer treatment.

Venkat Sankar et al, Genetic elements promote retention of extrachromosomal DNA in cancer cells, Nature (2025). DOI: 10.1038/s41586-025-09764-8

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Images that require less neural energy to process are generally rated as more aesthetically pleasing, indicating that visual preference may be influenced by the brain's tendency to conserve energy. This suggests that aesthetic appreciation is linked to a balance between adequate visual stimulation and minimizing metabolic expenditure.

Beauty may be 'easy on the eyes' because it saves brain power

Humans may find images that take less energy to process aesthetically pleasing, suggesting that our attraction to beauty is at least partially an energy conservation strategy. 

Looking at something can feel effortless, but in energetic terms, it isn't cheap. The brain uses 20% of the body's energy, and the visual system accounts for about 44% of that expenditure. Looking at very simple stimuli, like a blank white room, is energy-efficient but boring. Looking at very busy or unusual images can feel tiring and unpleasant. 

Publishing in PNAS Nexus, researchers presented 4,914 images of objects and scenes to an in-silico model of the visual system to estimate the number of neurons needed to look at them. The authors compared these estimates to enjoyment ratings from 1,118 participants recruited using Amazon Mechanical Turk.

Next, they used blood oxygen level-dependent signal brain imaging to measure the energy costs of looking at images for 4 participants. In both experiments, study participants found images that took less energy to process more attractive. The authors asked for a quick response, meant to capture initial impressions, not the more complex pleasures that may arise from contemplating an image in a broader context by engaging with its meaning.

According to the authors, visual aesthetic appreciation may be a manifestation of an energy-conserving heuristic that creates a sweet spot between sufficient stimulation of the visual system and excessive metabolic cost.

Yikai Tang et al, Less is more: Aesthetic liking is inversely related to metabolic expense by the visual system, PNAS Nexus (2025). DOI: 10.1093/pnasnexus/pgaf347

"Caching," is the scientific term for storing food in hidden places for later use. This behaviour is widespread across the animal kingdom, from squirrels, to crows, and wolves.

Caching behavior generally falls into one of two categories.

One is known as larder hoarding—think of a squirrel stashing nuts in just one or two places to draw from as they get through a long winter. 

 The other is known as scatter hoarding. It is where animals make smaller caches of surplus food in many different locations, reducing the chance of losing everything to a competitor or going hungry in lean seasons. It's mostly seen in wild canids such as foxes and wolves.  

This behavior in modern dogs is an instinctual remnant. It reflects the competitive feeding patterns of their ancestors who lived by hunting, for whom securing food was unpredictable, but crucial for survival. 

 Dogs appear to rely on a combination of scent and observational spatial memory to remember where they have cached special items, such as food, treats and toys.

https://theconversation.com/your-dog-is-not-a-doomsday-prepper-here...

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Exposure to fatty food odors during pregnancy and breastfeeding, even without maternal weight gain or high-fat intake, can alter offspring brain circuits related to reward and metabolism, increasing their risk of obesity and insulin resistance. Ingested flavoring agents with fatty odors were sufficient to trigger these effects in mice, highlighting potential implications for human metabolic health.

https://medicalxpress.com/news/2025-12-fatty-food-pregnancy-obesity...

Why your faucet drips: Water jet breakup traced to angstrom-scale thermal capillary waves

The breakup of a water jet into droplets is primarily triggered by intrinsic thermal capillary waves—angstrom-scale surface fluctuations—rather than external disturbances or nozzle imperfections. These minute thermal oscillations are amplified by Rayleigh-Plateau instability, determining the breakup length across a wide range of jet sizes.

Stefan Kooij et al, What Determines the Breakup Length of a Jet?, Physical Review Letters (2025). DOI: 10.1103/jf6w-l5sy

How airplanes discharge static electricity

Urban raccoons exhibit shorter snouts compared to rural populations, a trait associated with early domestication syndrome. This morphological change is likely driven by the advantages of tameness and reduced aggression in accessing human food waste. The findings suggest that proximity to humans can induce domestication-related traits in wild species.

Artem Apostolov et al, Tracking domestication signals across populations of North American raccoons (Procyon lotor) via citizen science-driven image repositories, Frontiers in Zoology (2025). DOI: 10.1186/s12983-025-00583-1

Which gut microbes matter most? Large study ranks bacteria by health and diet links

The gut microbiome has been a rising star in the world of health science over the last several years, garnering interest from both researchers and the general public. This is mostly due to its connection to general health and diseases, like type 2 diabetes and heart disease, as well as the fact that it is a modifiable element of human health. However, the science surrounding the fascinating world of gut microbes is still developing and there is much to learn.

A new study, published in Nature, has added significantly to our understanding of the human microbiome. The study team analyzed the gut microbiome, diet and health markers from over 34,500 people in the US and UK, and linked hundreds of specific gut microbe species to key indicators of health and diet. The data come from the Zoe PREDICT program in the UK and US, which is run by the microbiome testing company Zoe.

The researchers used machine learning to link certain gut microbe species in 34,694 study participants to diet and common health risk factors such as BMI, triglycerides, blood glucose and HbA1c, as well as clinical markers that are intermediary measures of cardiometabolic health. Out of 661 non-rare microbial species, the researchers focused in on the 50 that were most favorably associated with good health and the 50 that were the most unfavorably associated with good health.

This process resulted in the development of the "ZOE Microbiome Health Ranking 2025" and "Diet Ranking 2025," used to score microbes as either favorable or unfavorable for health on a scale of 0 to 1. Those closer to zero are considered positively correlated to the health markers and those closer to one are negatively correlated. This was done for all 661 microbes studied.

The ranking system identified hundreds of gut microbe species—described as species-level genome bins (SGBs) in the paper—significantly associated with health markers and diet quality. They found that favorable microbes were more common in people with lower BMI and fewer diseases, while unfavorable microbes were more common in those with obesity and disease. A part of the study focusing on BMI, used data from 5,348 healthy individuals, and divided them into three BMI categories; healthy weight, overweight and obese.

"Meta-analysis based on linear regression on single cohorts showed that individuals with healthy weight carried, on average, 5.2 more of the 50 favorably ZOE MB health-ranked SGBs than people with obesity," the study team writes.

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The team also assessed whether the ZOE MB health-ranked SGBs were more abundant in participants with a defined disease. Indeed, they found that people in the control group had higher favorably ranked gut microbes than people with disease, and that those with diseases had more unfavorably ranked gut microbes than those without disease.

Dietary interventions were also found to increase favorable microbes and reduce unfavorable ones. The team analyzed data from two studies, referred to as ZOE METHOD and BIOME, in which participants either followed a personalized dietary intervention program (PDP) designed to improve the microbiome or took a prebiotic supplement. The microbiomes of these participants changed significantly by the end of the studies.

"The dietary intervention groups of both clinical trials that aimed at improving diet using different approaches (prebiotic blend for BIOME and PDP for METHOD) showed the highest number of significantly changing SGBs. Focusing on the most significant gut microbial SGBs with the largest change in relative abundance after dietary interventions, they found increasing Bifidobacterium animalis—a bacterium present in dairy-based foods and in the microbiome of people consuming larger amounts of them, an unknown Lachnospiraceae bacterium and R. hominis both previously associated with a vegan diet, and another unknown Lachnospiraceae bacterium linked to a vegetarian diet," the authors explain.

In addition to linking known bacterial species to measures of health and diet, the team also discovered many key health-associated microbes that were previously uncharacterized species.

Francesco Asnicar et al, Gut micro-organisms associated with health, nutrition and dietary interventions, Nature (2025). DOI: 10.1038/s41586-025-09854-7

Part2

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How to build a genome: Scientists release troubleshooting manual for synthetic life

Leading synthetic biologists have shared hard-won lessons from their decade-long quest to build the world's first synthetic eukaryotic genome in a Nature Biotechnology paper. Their insights could accelerate development of the next generation of engineered organisms, from climate-resilient crops to custom-built cell factories.

The Synthetic Yeast Genome Project (Sc2.0) involved a large, evolving global consortium of 200-plus researchers from more than ten institutions, who jointly set out to redesign and chemically synthesize all 16 chromosomes of baker's yeast from scratch. Macquarie University contributed to the synthesis of two of these chromosomes, comprising around 12% of the project overall.

The process for each chromosome followed the same design principles: removing unstable genetic elements; introducing molecular 'watermarks' to distinguish synthetic DNA from natural sequences; and adding the gene-shuffling system "SCRaMbLE" so researchers could rearrange genes and test their functions.

Unlike traditional genetic engineering, which tweaks existing genomes, Sc2.0 was the first to rewrite an entire genome from the ground up—all 12 million base pairs of it.

Completing all 16 synthetic chromosomes lets us understand genome function at a scale that was simply impossible before.

The chromosomes were assembled in large chunks containing thousands of base pairs, then integrated into living yeast cells step by step, relying on yeast's own cellular machinery to stitch the synthetic pieces into place.

Despite the standardized design principles, every research team encountered similar problems. The paper catalogs these 'bugs' systematically, offering future synthetic biologists a roadmap of what to avoid.

Tiny DNA watermarks, designed to be silent, occasionally disrupted gene function in unexpected ways. Some genes flagged as non-essential turned out to cause significant growth problems when removed.

Yeast cannot regenerate mitochondrial genomes from scratch, so any damage required researchers to perform a genetic rescue operation, where they identified and fixed the problem, then had to reintroduce healthy mitochondria through careful breeding.

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Teams developed and shared sophisticated debugging tools, such as "Pooled PCRtag Mapping" (which allows researchers to screen hundreds of yeast colonies simultaneously to pinpoint which genetic changes caused problems) and "CRISPR D-BUGS' (combines gene editing with selection strategies).

The lessons from yeast are already informing bold new projects.

Plants grow slowly and are far more difficult to engineer than yeast, so this project uses an ingenious approach: building the synthetic plant chromosomes inside yeast cells first, then transferring the newly constructed chromosome into plant cells.

 Building synthetic chromosomes one yeast at a time: insights from Sc2.0, Nature Biotechnology (2025). DOI: 10.1038/s41587-025-02913-4

Part 2

Small galaxies may buck the black hole trend, Chandra finds

Most smaller galaxies may not have supermassive black holes in their centers, according to a recent study using NASA's Chandra X-ray Observatory. This contrasts with the common idea that nearly every galaxy has one of these giant black holes within their cores, as NASA leads the world in exploring the secrets of how the universe works.

A team of astronomers used data from more than 1600 galaxies collected in more than two decades of the Chandra mission. The researchers looked at galaxies ranging in heft from over ten times the mass of the Milky Way down to dwarf galaxies, which have stellar masses less than a few percent of that of our home galaxy. A paper describing these results has been published in The Astrophysical Journal.

The team has reported that only about 30% of dwarf galaxies likely contain supermassive black holes.

To reach their conclusion, the researchers considered both possibilities for the lack of X-ray sources in small galaxies in their large Chandra sample. The amount of gas falling onto a black hole determines how bright or faint they are in X-rays. Because smaller black holes are expected to pull in less gas than larger black holes, they should be fainter in X-rays and often not detectable. The researchers confirmed this expectation.

However, they found that an additional deficit of X-ray sources is seen in less massive galaxies beyond the expected decline from decreases in the amount of gas falling inwards. This additional deficit can be accounted for if many of the low-mass galaxies simply don't have any black holes at their centers. The team's conclusion was that the drop in X-ray detections in lower mass galaxies reflects a true decrease in the number of black holes located in these galaxies.
This result could have important implications for understanding how supermassive black holes form. There are two main ideas: In the first, a giant gas cloud directly collapses into a black hole, which contains thousands of times the sun's mass from the start. The other idea is that supermassive black holes instead come from much smaller black holes, created when massive stars collapse.
The formation of big black holes is expected to be rarer, in the sense that it occurs preferentially in the most massive galaxies being formed, so that would explain why we don't find black holes in all the smaller galaxies, say the researchers.

Fan Zou et al, Central Massive Black Holes Are Not Ubiquitous in Local Low-mass Galaxies, The Astrophysical Journal (2025). DOI: 10.3847/1538-4357/ae06a1

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Warblers borrow color-related genes from evolutionary neighbours, study finds

Wood warblers, also called New World warblers, are some of the most colorful birds in North America, with more than a hundred species in the family ranging in color from yellow, orange and red to blue, green and pink. A new study led by researchers at Penn State has uncovered several instances of the birds passing color-related genes to other species of wood warblers, including those that are not closely related.

This glimpse into the hidden evolutionary dynamics of these songbirds may help explain why some species display certain colors as well as how the group diversified into so many different species in such a relatively short evolutionary time, the researchers said.

A paper describing the research appeared Dec. 11 in the journal PLOS Biology.

It turns out that some of these birds may have borrowed colors from their neighbors, rather than evolving them independently. Scientists previously found evidence that a particular color-related gene had been shared between species within the same genus, which is one notch up on the taxonomic ladder, but now they show that there is gene movement from species in one genus to another. That means some genetic funny business was going on with these warblers millions of years ago.

In addition to the pigment melanin, which produces brown and black plumage, the colors of wood warblers are influenced by carotenoid pigments, which are responsible for bright yellow, red and orange plumage. The research team collected DNA from 400 warblers across 100 species and six subspecies, focusing on three main genes related to carotenoid pigments.

The team compared an evolutionary tree of the warblers—built using their entire genomes and representing the overall relationships among the birds—with trees they created independently for each of the three carotenoid-related genes. These gene-specific trees show similarities and differences of the individual gene across the family, and discrepancies between the trees suggest where gene exchanges may have occurred. Statistical follow-up tests confirmed the gene exchanges, which the researchers said resulted from a process called introgression.

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When birds of two different species mate, their hybrid offspring inherit genes from both parents. When that hybrid goes on to mate with an individual of one of its parent species, it can pass on genes from the other. Over several generations, the genetic material from one species can be incorporated into the other, which is called introgression.

The  research group previously identified introgression of a gene called BCO2 among several species of wood warblers within the genus Setophaga, but it seemed like the version of the gene that was getting passed around might have originated from outside that group. Here, they confirmed that this version of the gene came from outside the genus and found that it has been exchanged between species of a different genus on multiple occasions.

The gene beta-carotene oxygenase 2 (BCO2), when turned on, produces a protein that breaks down yellow carotenoids, resulting in more white or gray coloration. When turned off, BCO2 results in the accumulation of yellow carotenoids and thus yellow plumage.

The researchers found evidence of introgression of BCO2 among several wood warbler species, including from a species within the genus Leiothlypis to multiple Setophaga species as well as to multiple species in the genus Cardellina. They also observed introgression of BCO2 from the genus Vermivora to Geothlypis, though the order and exact timing of these exchanges remain unclear.

Scientists think the initial introgression events from Leiothlypis occurred between half a million to two million years ago—while the donor and recipient species themselves diverged several million years before that.

But the 'borrowed' version of this gene has stuck around all that time, even as the species themselves evolved and split.

While introgression of BCO2 from Leiothlypis to other species may have occurred millions of years ago, the researchers suggested that introgression into one species, the red-faced warbler, is not only more recent, but is currently in progress, as not all members of the species they sampled contained the borrowed version of the gene.

A colorful legacy of hybridization in wood-warblers includes frequent sharing of carotenoid genes among species and genera, PLOS Biology (2025). DOI: 10.1371/journal.pbio.3003501

Part 2

Scientists teach helices to switch shapes
Synthetic molecules can be programmed to form specific helical structures by embedding instructions in their sequence, enabling control over helix type and the ability to switch shapes in response to environmental changes. These helices possess internal cavities capable of trapping persistent pollutants like perfluorinated sulfonates, indicating potential for adaptive materials and environmental applications.

Dimitri Delcourt et al, Programmable Assembly of Multistranded Helices in Water, Nature Communications (2025). DOI: 10.1038/s41467-025-67227-0

Lab-developed mosquitoes prevent malaria parasite development, paving way for future field trials

In a new study published in Nature, scientists have successfully developed genetically modified mosquitoes in Tanzania that block the transmission of malaria.

In 2023, Transmission Zero's leading researchers created the first transgenic mosquito strain ever developed in Africa, in Tanzania. Its latest research offers a new solution by genetically modifying Anopheles gambiae mosquitoes (malaria-carrying mosquitoes) to block the development of malaria parasites, effectively reducing their ability to transmit the disease.
This approach allows these precise changes in the mosquitoes' ability to carry the malaria parasite to be passed down from one mosquito generation to the next.

These findings on Anopheles gambiae are the pathfinder for the technology to be extended to other equally important malaria vectors such as Anopheles arabiensis and Anopheles funestus, as well as vectors of diseases such as dengue and chikungunya.

Conducted entirely under containment, the study introduced antimalarial traits—naturally occurring molecules from frogs and honeybees—into local mosquito populations. The modified mosquitoes effectively prevented Plasmodium falciparum, the primary malaria parasite in Africa, from developing, creating a significant barrier to transmission.

While the results are promising, further research is required before field trials can begin.

Tibebu Habtewold et al, Gene-drive-capable mosquitoes suppress patient-derived malaria in Tanzania, Nature (2025). DOI: 10.1038/s41586-025-09685-6

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Farm-living families develop earlier immune maturation against food allergies, study finds

Children who grow up in farming communities have long been known to develop far fewer allergies than their urban peers. A new study offers one possible reason why: their immune systems may mature faster, and breast milk appears to play an important supporting role.

What this study shows is that their B cell and antibody responses are essentially ahead of schedule compared to urban infants. Their immune systems seem better equipped, earlier in life, to handle foods and other exposures without overreacting.

Farm-exposed infants had more memory and IgG+ B cells, suggesting earlier maturation of the antibody-producing system. They also had higher levels of IgG and IgA antibodies in blood, saliva, and stool, and higher IgA levels in human milk from their mothers. Taken together, the data point to a more robust and active antibody system in infants growing up in a traditional farming lifestyle.

Researchers saw a continuum: the more egg-specific antibodies in breast milk, the less likely babies were to develop egg allergy.

The  data suggest there may be particular benefit when mothers have high levels of food-specific antibodies in their milk. Not every mother does, and that could help explain why results have been mixed on the association between breastfeeding and food allergy.

Why do Mennonite mothers have more egg-specific antibodies? One likely factor is diet. Old Order Mennonite families typically raise their own chickens and eat eggs frequently. That repeated exposure appears to boost mothers' antibody levels against egg proteins, which then show up both in the bloodstream and in breast milk.

Just as an infection or a vaccine can boost your antibody levels, regularly eating certain foods could do the same.

The study also found differences in antibodies to other environmental allergens at birth. OOM infants were born with higher cord blood levels of IgG and IgG4 antibodies to dust mites and horse, reflecting their mothers' exposures, while urban infants had higher antibodies to peanut and cat. The team detected several food antigens in cord blood, and even antigen-specific IgA at birth, suggesting that in-utero exposure to food proteins may also shape early immunity.

Part 1

While maternal diet and breast milk antibodies are central to the new paper, the researchers emphasize that the "farm effect" is almost certainly multifactorial and can vary between individuals.

Courtney M. Jackson et al, Farm exposure in infancy is associated with elevated systemic IgG₄, mucosal IgA responses, and lower incidence of food allergy, Science Translational Medicine (2025). DOI: 10.1126/scitranslmed.ads1892

Part 2

Fake participants and bots threaten quality of online research data
Online qualitative research faces risks from fraudulent participants, including bots and ineligible humans, which can compromise data quality. Identifying and removing such responses is challenging but essential. Strategies to mitigate these risks include careful recruitment planning, screener surveys, and community-engaged methods to enhance data integrity.

Devon Ziminski et al, Preventing and mitigating fraudulent research participants in online qualitative violence and injury prevention research, BMJ Open Quality (2025). DOI: 10.1136/bmjoq-2025-003706