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Comment by Dr. Krishna Kumari Challa yesterday

A neural basis for flocking

When animals move together in flocks, herds, or schools, neural dynamics in their brain become synchronized through shared ways of representing space, a new study by researchers  suggests. The findings challenge the conventional view of how collective motion arises in nature.

Flocking animals, such as hundreds of birds sweeping across the sky in unison, are a mesmerizing sight. But how does their collective motion—seen in many species, from swarming locusts to schooling fish and flocking birds—arise?

Researchers have developed a novel theoretical framework that integrates neurobiological principles to upend long-held assumptions about how flocking behavior emerges in nature.

In a recent article published in Nature Communications they demonstrate that flocking does not require individuals to rely on rigid behavioral rules, as is typically assumed. Instead, it can arise naturally from a simple and widespread neural architecture found across the animal kingdom: the ring attractor network.

In the new model, flocking arises because neural activity in each animal becomes linked through perception: Every individual processes its surroundings using a ring attractor—a circular network of neurons that tracks the direction toward perceived objects in space. This way, the animal can maintain bearings toward others relative to stable features in the environment. The researchers found that when many such individuals interact, their neural dynamics synchronize, giving rise to spontaneous alignment and collective movement.

This means that coordinated motion can emerge directly from navigational processes in the brain, challenging decades of theory.

The new framework shows that collective motion emerges when individuals represent the directions of others relative to stable features in their surroundings—a world-centered, or allocentric, perspective. This mechanism underlies what the authors describe as "allocentric flocking."

Mohammad Salahshour et al, Allocentric flocking, Nature Communications (2025). DOI: 10.1038/s41467-025-64676-5

Comment by Dr. Krishna Kumari Challa yesterday

New lab-grown human embryo model produces blood cells

Scientists have used human stem cells to create three-dimensional embryo-like structures that replicate certain aspects of very early human development—including the production of blood stem cells. The findings are published in the journal Cell Reports.

Human blood stem cells, also known as hematopoietic stem cells, are immature cells that can develop into any type of blood cell, including red blood cells that carry oxygen and various types of white blood cells crucial to the immune system.

The embryo-like structures, which the scientists have named "hematoids," are self-organizing and start producing blood after around two weeks of development in the lab—mimicking the development process in human embryos.

The structures differ from real human embryos in many ways, and cannot develop into them because they lack several embryonic tissues, as well as the supporting yolk sac and placenta needed for further development.

Hematoids hold exciting potential for a better understanding of blood formation during early human development, simulating blood disorders like leukemia, and for producing long-lasting blood stem cells for transplants.

The human stem cells used to derive hematoids can be created from any cell in the body. This means the approach also holds great potential for personalized medicine in the future, by allowing the production of blood that is fully compatible with a patient's own body.

A post-implantation model of human embryo development includes a definitive hematopoietic niche, Cell Reports (2025). DOI: 10.1016/j.celrep.2025.116373. www.cell.com/cell-reports/full … 2211-1247(25)01144-1

Comment by Dr. Krishna Kumari Challa yesterday

Flipping the switch on sperm motility offers new hope for male infertility

Infertility affects about one in six couples, and male factors account for roughly half of all cases—often because sperm don't swim well. Researchers have uncovered a key component of the "switch" that keeps the movement signal strong, offering a promising new avenue for both diagnosis and treatment. When this switch is absent, sperm slow down, and fertilization fails. By restoring that signal in the lab, the team rescued swimming and achieved healthy births in mice.

The study has been published in Proceedings of the National Academy of Sciences.

For sperm to successfully fertilize an egg, they must be able to swim, a process driven by their tail. This movement is activated by an essential signaling molecule called cyclic AMP (cAMP). While it was known that an enzyme named soluble adenylyl cyclase (sAC) produces cAMP inside sperm, the precise mechanism controlling this enzyme's stability and function remained largely a mystery.

The study focused on a protein with a previously unknown function, TMEM217, which is produced specifically in the testes. They engineered mice that could not produce TMEM217 and found that the males were completely infertile, with sperm that were almost entirely immotile. Further investigation revealed that TMEM217 partners with another protein, SLC9C1, to form a stable complex.

This complex is crucial for maintaining the presence of the sAC in mature sperm. Without TMEM217, SLC9C1 is lost and sAC is markedly reduced, causing cAMP levels to plummet and sperm motility to fail.  

In a significant breakthrough, the team took the immotile sperm from these mice and treated them with a cAMP analog—a molecule that mimics cAMP. This treatment successfully restored the sperm's movement and enabled them to fertilize eggs in vitro, leading to the birth of healthy pups.

The study has revealed a fundamental "switch" in sperm, providing a deeper understanding of sperm motility regulation. The discovery of the TMEM217-SLC9C1-sAC axis offers a new target for diagnosing unexplained cases of male infertility.

Formation of a complex between TMEM217 and the sodium-proton exchanger SLC9C1 is crucial for mouse sperm motility and male fertility, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2516573122

Comment by Dr. Krishna Kumari Challa yesterday

Rewriting the rules of genetics: Study reveals gene boundaries are dynamic, not fixed

Molecular biologists have long thought that the beginning of a gene launched the process of transcription—the process by which a segment of DNA is copied into RNA and then RNA helps make the proteins that cells need to function.

But a new study published in Science by researchers challenges that understanding, revealing that the beginning and end of genes are not fixed points, but move together—reshaping how cells build proteins and adapt through evolution.

This work rewrites a textbook idea: the beginning of a gene doesn't just launch transcription—it helps decide where it stops and what protein you ultimately make. 

For years, we taught that a gene's 'start' only decides where transcription begins. We now show the start also helps set the finish line—gene beginnings control gene endings, say the researchers  of this new work.

The discovery offers a promising new strategy for targeting cancer and neurological disorders, as well as developmental delays and aging. When gene transcription is disrupted or misregulated, protein production can become abnormal, potentially causing tumor growth.

The understanding that the beginning and ends of genes are connected could allow physicians to redirect gene expression—restoring healthy protein variants and suppressing harmful ones, without altering the underlying DNA sequence.

Misplacing a start or an end isn't a small mistake—it can flip a protein's domain structure and change its function, too. In cancer, that flip can mean turning a tumor suppressor into an oncogene. An oncogene is a mutated gene that has the potential to cause cancer by promoting uncontrolled cell growth and division.

These new findings show that controlling where a gene begins is a powerful way to control where it ends—and, ultimately, what a cell can do. 

Ezequiel Calvo-Roitberg et al, mRNA initiation and termination are spatially coordinated, Science (2025). DOI: 10.1126/science.ado8279

Comment by Dr. Krishna Kumari Challa on Tuesday

Do plastics have toxic effects on the heart? Higher exposure linked to changes in heart rhythms

We've all heard warnings about BPA—a chemical found in plastics and personal care products. Studies show that nearly millions of people around the world have detectable levels of BPA in their bodies. Now, new research has revealed this everyday exposure is tied to changes in the heart's electrical system.

Phenols are a wide variety of chemicals. The best-known example is BPA.

BPA can be found in water bottles, food can linings, cash register receipts, eyeglass lenses, even baby bottles and makeup. These are environmental phenols—chemicals in products we touch every day.

 So researchers studied 600 people. Urine tests and EKGs found higher exposure was linked to changes in heart rhythms.

The electrical conduction literally keeps us alive. If it gets altered in any way, you could die immediately, say cardiologists.

Healthy individuals should not be affected by this. But if you find a person that's genetically predisposed, that is older, these can lead to potential changes.

https://www.uc.edu/news/articles/2025/10/do-plastics-have-toxic-eff...

Comment by Dr. Krishna Kumari Challa on Tuesday

Nanoplastics detected in farm animal cells: Study warns of possible human consequences

Scientists at the Research Institute for Farm Animal Biology (FBN) in Dummerstorf and the University of Udine have detected the uptake of nanoplastics in farm animal cell cultures. The results provide evidence of potential risks to animal health, meat production and also human food safety.

Plastic bags, packaging, yogurt lids—items that are carelessly thrown away decompose over years into tiny plastic particles. They end up in soil, waterways and ultimately in our food chain. Although numerous studies have already shown that microplastics can harm marine animals, birds and insects, the effects of nanoplastics on livestock have hardly been researched to date.

Unlike microplastics (1 µm–5 mm), there are currently few adequate methods for detecting nanoplastics (< 1 µm) in humans and animals. However, researchers assume that these small particles can also accumulate in tissue.

In a new study, researchers have demonstrated the uptake of nanoplastic particles made of polystyrene into cultured cells from cattle and pigs. This absorption led to changes that could impair the cell function and health of the animals in the long term.

The study examined granulosa cells from cattle, which play an important role in reproduction, and myoblasts from pigs, which are used to form muscle tissue. Even low concentrations led to microscopically visible accumulations. These could impair the fertility of the animals and their products.
Farm animals are part of the human food chain. Direct health risks to consumers cannot be inferred at present. Nevertheless, the researchers urge for more detailed investigations into the long-term consequences of microplastics and nanoplastics.

Francesca Corte Pause et al, Exploring the influence of polystyrene-nanoplastics on two distinct in vitro systems in farm animals: A pilot study, Science of The Total Environment (2025). DOI: 10.1016/j.scitotenv.2025.179378

Comment by Dr. Krishna Kumari Challa on Tuesday

The migration period has started. Millions of birds are migrating now.

But birds face a variety of threats during migration—collisions with windows, communications towers and wind turbines; light pollution that disorients them; habitat loss or degradation in their migration stopover areas; human disturbance while feeding at stopover areas; predators; and storms.

Artificial light is one of the biggest dangers for birds traveling at night. It can confuse or attract them toward buildings, where they may crash into windows.

Birds collide with windows when they can't see them or, even worse, are attracted to them because of reflections of plants or the sky.This happens during the day, as well as at night during migration when lights disorient birds or if fog is causing them to fly low.

That's why people have an important role to play, say experts. The three most important things you can do for birds this time of year are to keep cats indoors, turn your lights off and use window mitigation.

Turn off unnecessary outdoor lighting at night or use motion sensors and timers so lights are only on when needed. If you must leave a light on, use warm-colored lights with shields that face downward.

Homeowners can also help reduce window collisions by: Placing bird feeders within three feet of windows or more than 30 feet away

Using window screens, UV tape or hanging cords to make glass visible

Closing blinds to limit reflections

Leaving fallen logs or stick piles in yards to give birds shelter as they stop to rest.

Enjoy these visitors as they pass through. But feed responsibly! Clean your feeders regularly, follow window guidance, and keep your cats indoors.

Comment by Dr. Krishna Kumari Challa on Tuesday

Seafood unfairly singled out in microplastics debate, researchers say

Seafood has received disproportionate attention in media coverage about microplastics, despite evidence that fish and shellfish are not the main source of human exposure, according to a new scientific review.

Researchers found that more than 70% of scientific and media coverage on microplastics in food has focused on seafood, contributing to the public perception that eating fish is the biggest risk.

This misperception has real consequences, as some consumers report reducing consumption of seafood because of concerns over microplastics exposure, and thereby miss out on the health benefits of seafood consumption. The findings are reported in the journal Environmental Science & Technology Letters.

In reality, people are far more exposed to microplastics from indoor air and dust.

A previous study reported that the presence of microplastics in mussels collected from the environment was lower than the amount of microplastics that falls on a plate of mussels during dinner time in a typical household.

Seafood, including mussels and oysters and finfish like salmon and cod, may contribute 1–10 microplastic particles per day, which is consistent with other foods, like salt, honey and chicken.

Ingestion from bottled water is estimated at 10 to 100 particles per day, and exposure from indoor air accounts for considerably higher exposure—100 to 1,000 particles per day.

There is minimal evidence that they pose a health risk. The evidence we do have indicates that plastic particles readily pass through the digestive tract and exit the body.

While there are perceptions that toxic substances associated with plastic particles may pose health risks, evidence indicates concentrations are actually exceedingly low compared to other sources of exposure.

Theodore B. Henry et al, Examining Misconceptions about Plastic-Particle Exposure from Ingestion of Seafood and Risk to Human Health, Environmental Science & Technology Letters (2025). DOI: 10.1021/acs.estlett.5c00551

Comment by Dr. Krishna Kumari Challa on Tuesday

Rare Earth Elements: 17 Minerals More Valuable Than Gold in Today’s Tech World

Comment by Dr. Krishna Kumari Challa on Tuesday

Enrollment involved 198 adults at two academic cardiac surgery centers in Germany, all undergoing first-time isolated CABG for three-vessel or left main disease, without prior arrhythmias, monitored for one year after implant of a device during surgery.

Patients were followed through continuous rhythm surveillance using an insertable cardiac monitor placed at skin closure. AF was defined as device-detected and adjudicated episodes lasting at least two minutes.

Within one year, 95 of 198 patients developed new-onset AF, yielding a cumulative incidence of 48% with a 95% CI of 41%–55%. Standard monitoring identified a 34% cumulative incidence with a 95% CI of 27%–41% and Gray's test P = .01 versus continuous monitoring. Sensitivity analyses using longer episode thresholds produced cumulative incidences of 46% at four minutes, 45% at six minutes, and 44% at 12 minutes.

Across the cohort with new-onset AF, median AF burden over the first year measured 0.07%, corresponding to 370 minutes. Early postoperative days carried the most arrhythmia time, with median burden of 3.65% on days 1–7, 0.04% on days 8–30, and 0% on days 31–365. A total of 2,053 episodes, accounting for 2,522 hours, were recorded, with a median episode length of six minutes and a median time-to-incident episode of 3.3 days. Asymptomatic presentations comprised 63% of episodes, and 67% were not captured by standard monitoring.

Among 95 patients with AF, 73 patients had incident episodes within seven days and 90 within 30 days, and 45% of accumulated AF time occurred within the first seven days and 77% within 30 days.

Recurrent AF later than 30 days appeared in 19 of 90 patients with incident episodes prior to 30 days, totaling 554 episodes with a median length of four minutes. Asymptomatic recurrences comprised 43% of these later episodes, and 3% were detected by standard monitoring.

The authors conclude that continuous monitoring uncovers substantially more AF than standard surveillance, while measured burden remains very low after 30 days.
Their findings question routine long-term oral anticoagulation after new-onset AF following CABG and support reassessment at 30 days when treatment is initiated.

Florian E. M. Herrmann et al, Long-Term Continuous Monitoring of New-Onset Atrial Fibrillation After Coronary Artery Bypass Grafting, JAMA (2025). DOI: 10.1001/jama.2025.14891

Gregory M. Marcus, Is There Really Something Different About Postoperative Atrial Fibrillation After Cardiac Surgery?, JAMA (2025). DOI: 10.1001/jama.2025.15275

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