Comment

Comment by Dr. Krishna Kumari Challa 2 minutes ago

Repair in mammals often proceeds through scarring, a process that rapidly seals wounds without restoring original tissue architecture. This may reflect an evolutionary trade-off in larger or more complex organisms, where fast tissue sealing through fibrosis can ensure immediate survival, even at the cost of long-term function or structural integrity.

Greater understanding of the requirements for regeneration in worms and other regenerating species brings science closer to the goal of one day reverse-engineering regenerative responses in therapeutic settings.

Clare L.T. Booth et al, Developmental onset of planarian whole-body regeneration depends on axis reset, Current Biology (2025). DOI: 10.1016/j.cub.2025.03.065

Part 2

Comment by Dr. Krishna Kumari Challa 2 minutes ago

Stem cells need positional signals to drive regeneration

Scientists  have discovered that Schmidtea polychroa, a flatworm capable of regenerating lost tissue, develops this ability progressively during early life stages. Whole-body regeneration emerges during specific embryonic and juvenile stages, with head regeneration limited until the organism gains the capacity to reset its body's main axis. Stem-like cells are necessary for tissue growth yet insufficient on their own to trigger full regeneration.

Regeneration encompasses biological processes that replace tissues during normal maintenance or after injury. Some aquatic invertebrates such as hydrozoans, planarians, and acoels can regenerate entire bodies from mere tissue fragments. Certain fish, amphibians, and reptiles can regrow lost appendages.

Regenerative abilities change throughout an organism's life. In many species, embryos and juveniles regenerate more readily than adults. Aging has been associated with reduced regeneration in structures such as the mouse heart and digit tip, Xenopus limbs and tail, and Drosophila imaginal disks.

Even highly regenerative animals like tunicates and sponges show reduced ability as they age. These changes have been linked to stem cell exhaustion, loss of cellular plasticity, epigenetic alterations, and metabolic shifts. Gains in regenerative ability during adulthood have also been observed in sponges, crinoids, ctenophores, annelids, tunicates, and some vertebrates such as Xenopus tadpoles and certain lizards.

Planarian flatworms retain whole-body regenerative capacity into adulthood. Their regenerative ability depends on adult pluripotent stem cells, called neoblasts, which are distributed throughout the body. Neoblasts respond to injury through position-specific signaling from surrounding tissues and generate new tissues during maintenance, asexual reproduction, and regeneration.

Research Results reveal that whole-body regeneration is not an inherent, default property of possessing stem cells but instead depends on developmental cues that enable axis reset. The ability to regenerate a head only emerged after embryos gained competence to reset anterior-posterior polarity. Fragments containing functional progenitor cells still failed to regenerate unless specific polarity signals were activated.

Axis reset emerges as a critical gatekeeper in whole-body regeneration, with direct manipulation of signaling pathways enabling regeneration in fragments previously unable to recover. Findings point to regeneration as a conditional capability, one that may be switched on or off depending on developmental state and molecular context.

Broader strategies to induce regeneration in less regenerative animals may require restoring not just stem cell presence, but also the injury-induced cues that trigger polarity establishment and tissue identity. Results may challenge assumptions that regenerative loss is irreversible and suggest new targets for restoring tissue-forming potential.

Mammals, including humans, have limited regenerative capacity and are restricted to replacing select tissues and cell types.

Part 1

Comment by Dr. Krishna Kumari Challa 10 minutes ago

Lesions on the left iliac spine of 6DT19. Credit: PLOS One (2025). DOI: 10.1371/journal.pone.0319847

Part 2

Comment by Dr. Krishna Kumari Challa 37 minutes ago

First skeletal evidence of gladiator bitten by lion in Roman period

A study has uncovered the first physical evidence of human-animal gladiatorial combat in the Roman period.

The research, published in PLOS One, presents compelling skeletal evidence of a human victim attacked by a large carnivorous animal, likely within the context of Roman-era spectacle combat. It was conducted by an international team of archaeologists and osteologists.

While images of gladiators being bitten by lions have appeared in ancient mosaics and pottery, this is the only convincing skeletal evidence using forensic experiments anywhere in the world of bite marks produced by the teeth of a large cat, such as a lion.

The findings center on a single skeleton discovered in a Roman-period cemetery outside York in England, a site believed to contain the remains of gladiators. The individual's bones exhibited distinct lesions that, upon close examination and comparison with modern zoological specimens, were identified as bite marks from a large feline species.

The bite marks on the pelvis of the skeleton represent the first osteological confirmation of human interaction with large carnivores in a combat or entertainment setting in the Roman world.

For years, our understanding of Roman gladiatorial combat and animal spectacles has relied heavily on historical texts and artistic depictions. This discovery provides the first direct, physical evidence that such events took place in this period, reshaping our perception of Roman entertainment culture in the region.

Unique osteological evidence for human-animal gladiatorial combat in Roman Britain, PLOS One (2025). DOI: 10.1371/journal.pone.0319847. journals.plos.org/plosone/arti … journal.pone.0319847

Part 1

Part 2 ( on top of this contain pics)

Comment by Dr. Krishna Kumari Challa 1 hour ago

Scientists discover how memories control metabolism

New multidisciplinary research shows that the brain forms memories of cold experiences and uses them to control our metabolism. This study is the first to show that cold memories form in the brain—and map out how they subsequently drive thermoregulation.

The discovery may have important applications in therapies designed to treat a range of disorders—from obesity to cancer—in which thermoregulation and metabolism (or a lack of control in this area) play a role, as well as opening the door to more fundamental research, which could help us better understand how memories impact our behavior and emotions.

Long-term memories are stored in the brain as ensembles of inter-connected cells, termed engrams. Increasingly, modern neuroscience is beginning to identify engrams that encode for bodily representations, such as experiences of infection; inflammation; food consumption; and pain.

The researchers behind this work hypothesized that the brain may form engrams for temperature representations, and that these would serve to help an organism survive in changing temperatures.

Numerous clinical disorders, ranging from obesity to forms of cancer, may be treated by manipulating thermoregulation through brown adipose tissue. In the future, it will be important to test whether the manipulation of cold memories in humans could provide novel avenues for altering metabolism for therapeutic purposes.

This research opens many new doors for further discovery research, as well as the development of treatments. Understanding how representations of cold experiences affect broader brain functions such as emotion, decision-making, and social behavior will provide insights into the embodied nature of the mind, for example.

The sophisticated aspects of our minds evolved from more basic, visceral, bodily representations.

 Tomás Ryan, Cold memories control whole-body thermoregulatory responses, Nature (2025). DOI: 10.1038/s41586-025-08902-6. www.nature.com/articles/s41586-025-08902-6

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Comment by Dr. Krishna Kumari Challa 1 hour ago

Scientists have found a way to 'tattoo' tardigrades

Tardigrades are clumsy, eight-legged creatures, nicknamed water bears, are about half a millimeter long and can survive practically anything: freezing temperatures, near starvation, high pressure, radiation exposure, outer space and more. Researchers reporting in the journal Nano Letters took advantage of the tardigrade's nearly indestructible nature and gave the critters tiny "tattoos" to test a microfabrication technique to build microscopic, biocompatible devices.

Through this technology,scientists are not just creating micro-tattoos on tardigrades—they are extending this capability to various living organisms, including bacteria.

Microfabrication has revolutionized electronics and photonics, creating micro- and nanoscale devices ranging from microprocessors and solar cells to biosensors that detect food contamination or cancerous cells. But the technology could also advance medicine and biomedical engineering, if researchers can adapt microfabrication techniques to make them compatible with the biological realm.

Researchers employed a process that carves a pattern with an electron beam into a thin layer of ice coating living tissue, called ice lithography, leaving behind a design when the remaining ice sublimates. And what creature is better suited to being frozen, coated in ice, and then exposed to an electron beam than the nearly indestructible tardigrade?

The team put tardigrades into a cryptobiotic state (a sort of half-dead, suspended animation) by slowly dehydrating the microscopic animals. Then, the researchers placed an individual tardigrade onto a carbon-composite paper, cooled the sheet below -226°F (-143°C), and covered the water bear with a protective layer of anisole—an organic compound that smells like anise. The frozen anisole protected the tardigrade's surface from the focused electron beam as it drew the pattern.  

When exposed to the beam, the anisole reacted and formed a new biocompatible chemical compound that stuck to the tardigrade's surface at higher temperatures. As the tardigrade warmed to room temperature under vacuum, any unreacted frozen anisole sublimated and left behind the pattern of reacted anisole. Finally, the researchers rehydrated and revived the tardigrade, which then sported a new tattoo.

The precision of this technique allowed the team to create a variety of micropatterns: squares, dots, and lines as small as 72 nanometers wide, and even the university's logo. About 40% of the tardigrades survived the procedure, and the researchers say that could be improved with further fine tuning. Most importantly, the tardigrades didn't seem to mind their new tattoos: Once rehydrated, they showed no changes in behavior. These results indicate that this technique could be suitable for printing micro-electronics or sensors onto living tissue.

It is challenging to pattern living matter, and this advance portends a new generation of biomaterial devices and biophysical sensors that were previously only present in science fiction. This work could enable advancements such as microbial cyborgs and other biomedical applications in the future.

Zhirong Yang et al, Patterning on Living Tardigrades, Nano Letters (2025). DOI: 10.1021/acs.nanolett.5c00378

Comment by Dr. Krishna Kumari Challa 23 hours ago

Antibiotic pollution in rivers follows 65% increase in human consumption, study shows

Human consumption of antibiotics increased by 65% between 2000 and 2015. These drugs are not completely metabolized while passing through the body, nor completely destroyed or removed by most wastewater treatment facilities.

Published in PNAS Nexus,  researchers calculate that worldwide humans consume around 29,200 tonnes of the 40 most used antibiotics. After metabolism and wastewater treatment, an estimated 8,500 tonnes (29% of consumption) may reach the world's river systems, and 3,300 tonnes (11%) may arrive at the world's oceans or inland sinks (such as lakes or reservoirs).

The authors calculate these figures using a model validated by data on measured concentrations of 21 antibiotics at 877 locations globally. While the total amounts of antibiotic residues translate into only very small concentrations in most rivers, which makes the drugs very difficult to detect, chronic environmental exposure to these substances can still pose a risk.

Antibiotics in rivers and lakes can reduce microbial diversity, increase the presence of antibiotic-resistant genes, and possibly impact the health of fish and algae. The authors calculate that levels of antibiotics are high enough to create a potential risk for aquatic ecosystems and antibiotic resistance during low-flow conditions (i.e., at times of less dilution) on 6 million kilometers of rivers.

Waterways with high concentrations are found across all continents, with the most impacted regions located in Southeast Asia. Amoxicillin is the antibiotic most often predicted to be found at high-risk concentrations and is the most-consumed antibiotic around the world.

The authors note that this version of their model does not include antibiotics given to livestock, which include many of the same drugs, or pharmaceutical manufacturing waste. However, the results show that antibiotic pollution in rivers arising from human consumption alone is a critical issue, which would likely be exacerbated by veterinary or industry sources of related compounds.

According to the authors, monitoring programs and strategies to manage antibiotic contamination of waterways, especially in areas at risk, are warranted.

Heloisa Ehalt Macedo et al, Antibiotics in the global river system arising from human consumption, PNAS Nexus (2025). DOI: 10.1093/pnasnexus/pgaf096

Comment by Dr. Krishna Kumari Challa yesterday

Himalayan snow at 23-year low, threatening 2 billion people: report

Snowfall in Asia's Hindu Kush-Himalayan mountain range has reached a 23-year low, threatening nearly two billion people dependent on snowmelt for water, scientists warned in a report this week.

The Hindu Kush-Himalayan range, which stretches from Afghanistan to Myanmar, holds the largest reserves of ice and snow outside the Arctic and Antarctica and is a vital source of fresh water for about two billion people.

Researchers found "a significant decline in seasonal snow across the Hindu Kush Himalaya region, with snow persistence (the time snow remains on the ground) 23.6% below normal — the lowest in 23 years," the International Center for Integrated Mountain Development (ICIMOD) said.

"This trend, now in its third consecutive year, threatens water security for nearly two billion people," it said in its Snow Update Report.

The study also warned of "potential lower river flows, increased groundwater reliance, and heightened drought risk."

Several countries in the region have already issued drought warnings, with upcoming harvests and access to water at risk for populations already facing longer, hotter, and more frequent heatwaves.

The inter-governmental ICIMOD organization is made up of member countries Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan.

It urged countries that rely on the 12 major river basins in the region to develop "improved water amangement, stronger drought preparedness, better early warning systems, and greater regional cooperation."

The Mekong and Salween basins -- the two longest rivers in Southeast Asia supplying water to China and Myanmar -- had lost around half of their snow cover, it noted.

Source: News Agencies

Comment by Dr. Krishna Kumari Challa yesterday

Microplastics still slip through wastewater treatment plants, carrying pollutants and threatening long-term health

Despite advances in wastewater treatment, tiny plastic particles called microplastics are still slipping through, posing potential health and environmental hazards, according to new research.

Because plastic is inexpensive to produce yet lightweight and sturdy, manufacturers have found it ideal for use in nearly every consumer good, from food and beverage packaging to clothing and beauty products. The downside is that when a plastic item reaches the end of its useful life, it never truly disappears. Instead, it breaks down into smaller and smaller pieces called microplastics—particles five millimeters or less, about the width of a pencil eraser—that end up in our soil and water.

 Systematic literature review found  that while most waste water treatment facilities significantly reduce microplastics loads, complete removal remains unattainable with current technologies. The study is  published in Science of the Total Environment.

As a result, many microplastics are being reintroduced into the environment, likely transporting other residual harmful pollutants in wastewater, such the chemicals Bisphenols, PFAS and antibiotics. These microplastics and organic pollutants would exist in trace levels, but we can get exposure through simple actions like drinking water, doing laundry or watering plants, leading to potential long-term serious human health impacts such as cardiovascular disease and cancer.

The researchers  found that the effectiveness of treatments varies depending on the technology communities use and how microplastics are measured to calculate the removal rates.

Jenny Kim Nguyen et al, A review on microplastic fibers and beads in wastewater: The current knowledge on their occurrence, analysis, treatment, and insights on human exposure impact, Science of The Total Environment (2025). DOI: 10.1016/j.scitotenv.2025.178818

Comment by Dr. Krishna Kumari Challa yesterday

New quantum-based navigation system 50 times more accurate than traditional GPS

A team of researchers has announced the successful demonstration of its newly developed quantum navigation system called "Ironstone Opal."

The group has written a paper describing how their system works and how well it tested against currently available backup GPS systems and has posted it on the arXiv preprint server.

With the advent and subsequent reliance on GPS by private and military vehicles and aircraft for navigation, governments have come to understand how vulnerable such systems can be. Outages can lead to drivers being stranded, pilots scrambling to use outdated systems and difficulties deploying military assets. I myself have faced these difficulties when I was stranded in the middle of roads and also wilderness.

Because of that, scientists around the world have been looking for reasonable backup systems, or even possible alternatives to GPS.

In this new effort, the team at Q-CTRL has developed such a backup system and is claiming that it is 50 times more accurate than any other backup GPS currently available under some scenarios.

The new system, Ironstone Opal, uses quantum sensors that are so sensitive they can be used to precisely self-locate an object using the Earth's magnetic field. The team at Q-CTRL noted that the magnetic field varies depending on location relative to the Earth. To take advantage of that, they built sensors that can precisely read the field and then use AI-based software to give X and Y geographic coordinates in the same fashion as GPS.

The researchers note that their system is passive, which means it does not emit signals that could be "heard" by other devices and cannot be jammed. They also note that their software system can filter out noise generated by vehicles or planes carrying the sensors. They point out that the system is small enough to be installed in any car, truck, or other land vehicle, as well as in drones and other aircraft.

Testing of the system on the ground, the researchers claim, showed it to be 50 times as accurate as any other GPS backup system. In the air, it was found to be 11 times more accurate than other backup systems..

 Murat Muradoglu et al, Quantum-assured magnetic navigation achieves positioning accuracy better than a strategic-grade INS in airborne and ground-based field trials, arXiv (2025). DOI: 10.48550/arxiv.2504.08167

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