Comment

Comment by Dr. Krishna Kumari Challa 1 hour ago

How pigments affect the weight of bird feathers

Birds are some of the most striking creatures on Earth, coming in a rainbow of colors that serve several important functions, such as attracting a mate and communicating with other birds. These vibrant hues are produced by pigments, primarily melanin, but a major unknown until now was how much these pigments weigh. Since wings need to be as light as possible for flight, understanding pigmentation weight may tell us something about the trade-off between the evolutionary benefits of colored feathers and the physical cost of carrying that weight.

In a new study published in the journal Biology Letters, scientists  have investigated how much melanin adds to the weight of feathers and the difference in weight between the two main chemical forms of melanin—eumelanin (responsible for brown and black colors) and pheomelanin (responsible for reds and lighter colors).

The researchers analyzed the feathers from 109 bird specimens across 19 different species, including the common kingfisher (Alcedo atthis), the golden eagle (Aquila chrysaetos) and the Eurasian bullfinch (Pyrrhula pyrrhula). They examined feathers with mixed colors and those with single, pure colors, and used a chemical process involving sodium hydroxide or caustic soda, as it is more commonly known, to extract the pigments. Once extracted, they were weighed and compared to the original weight of the feathers.

According to the scientists, melanin pigments account for about 22% of a feather's total weight, and in the most pigmented feathers, this weight is no more than 25%. Additionally, the two types of pigments don't weigh the same. Eumelanin, which makes feathers black or brown, was significantly heavier than pheomelanin, which produces lighter colors.

The paper suggests that a bird has to expend more energy to carry the weight of certain feather colors, which could explain why birds have evolved such a wide variety of hues, as the scientists write in their paper. 

The researchers suggested that birds in cold climates, like snowy owls, didn't just evolve white feathers for camouflage. The lack of a heavy pigment would allow them to grow thicker, more insulating feathers without adding too much weight. Therefore, they can stay warm and still be able to fly. Additionally, migratory birds may have evolved lighter feathers to reduce the energy cost of flying long distances.

Ismael Galván et al, Pigment contribution to feather mass depends on melanin form and is restricted to approximately 25%, Biology Letters (2025). DOI: 10.1098/rsbl.2025.0299

Comment by Dr. Krishna Kumari Challa 1 hour ago

Glow-in-the-dark succulents that recharge with sunlight could pave way to plant-based lighting systems

From mushrooms that cast a soft green glow to plankton that glimmers sparkling blue, glowing plants are nothing new to nature. Now, scientists are bringing that light to houseplants.

Reporting in the journal Matter, researchers crafted glow-in-the-dark succulents that recharge in sunlight. Injected with light-emitting compounds, the plants can shine in various colors and rival a small night light at their brightest. The simple, low-cost method may help lay the foundation for sustainable, plant-based lighting systems.

Researchers used afterglow phosphor particles—materials similar to those found in glow-in-the-dark toys. These compounds absorb light and release it slowly over time.

For the particles to travel through leaf tissues, the researchers had to get the size just right: around 7 micrometers, roughly the width of a red blood cell.

Smaller, nano-sized particles move easily within the plant but are dimmer. Larger particles glowed brighter but couldn't travel far inside the plant.

The team then injected the particles into several plant species, including succulents and non-succulents like golden pothos and bok choy. But only the succulents produced a strong glow, thanks to the narrow, uniform, and evenly distributed channels within the leaf that helped to disperse the particles more effectively. After a couple of minutes of exposure to sunlight or indoor LED light, the modified plants glowed for up to two hours.

The particles diffused in just seconds, and the entire succulent leaf glowed.

By using different types of phosphors, the researchers created plants that shine in various colors, including green, red, and blue. They even built a glowing plant wall with 56 succulents, bright enough to illuminate nearby objects and read texts.

Each plant takes about 10 minutes to prepare.

The glowing succulents' light fades over time, and the team is still studying the long-term safety of the materials for the plants.

Sunlight-powered multicolor and uniform luminescence in material-engineered living plants, Matter (2025). DOI: 10.1016/j.matt.2025.102370

Comment by Dr. Krishna Kumari Challa 1 hour ago

Cells 'vomit' waste to promote healing, but it comes with a trade-off

When injured, cells have well-regulated responses to promote healing. These include a long-studied self-destruction process that cleans up dead and damaged cells as well as a more recently identified phenomenon that helps older cells revert to what appears to be a younger state to help grow back healthy tissue.

Now, a new study in mice  reveals a previously unknown cellular purging process that may help injured cells revert to a stem cell-like state more rapidly. The investigators have dubbed this newly discovered response cathartocytosis, taking from Greek root words that mean cellular cleansing.

Published in the journal Cell Reports, the study used a mouse model of stomach injury to provide new insights into how cells heal—or fail to heal—in response to damage, such as from an infection or inflammatory disease.

After an injury, the cell's job is to repair that injury. But the cell's mature cellular machinery for doing its normal job gets in the way. So, this cellular cleanse is a quick way of getting rid of that machinery so it can rapidly become a small, primitive cell capable of proliferating and repairing the injury. Researchers identified this process in the GI tract, but they suspect it is relevant in other tissues as well.

The researchers identified cathartocytosis within an important regenerative injury response called paligenosis. 

In paligenosis, injured cells shift away from their normal roles and undergo a reprogramming process to an immature state, behaving like rapidly dividing stem cells, as happens during development. Originally, the researchers assumed the decluttering of cellular machinery in preparation for this reprogramming happens entirely inside cellular compartments called lysosomes, where waste is digested in a slow and contained process. From the start, though, the researchers noticed debris outside the cells. They initially dismissed this as unimportant, but the more external waste they saw in their early studies, the more they began to suspect that something deliberate was going on. They utilized a model of mouse stomach injury that triggered the reprogramming of mature cells to a stem cell state all at once, making it obvious that the "vomiting" response—now happening in all the stomach cells simultaneously—was a feature of paligenosis, not a bug.

In other words, the vomiting process was not just an accidental spill here and there, but a newly identified, standard way cells behaved in response to injury.

Although they discovered cathartocytosis happening during paligenosis, the researchers said cells could potentially use cathartocytosis to jettison waste in other, more worrisome situations, like giving mature cells that ability to start to act like cancer cells.

While the newly discovered cathartocytosis process may help injured cells proceed through paligenosis and regenerate healthy tissue more rapidly, the trade-off comes in the form of additional waste products that could fuel inflammatory states, making chronic injuries harder to resolve and correlating with an increased risk of cancer development.

 Jeffrey W. Brown et al, Cathartocytosis: Jettisoning of cellular material during reprogramming of differentiated cells, Cell Reports (2025). DOI: 10.1016/j.celrep.2025.116070

Comment by Dr. Krishna Kumari Challa 20 hours ago

Why Were Dinosaurs So Big?

Metabolic adaptations, air sac-filled bones, and evolutionary pressure likely contributed to dinosaurs’ gigantism.

Scientists have found evidence that the long-necked and long-tailed sauropods had a comparatively slower metabolism relative to today’s large mammals, which indicates that they likely didn’t have to eat as much. (1)

And when sauropods did eat, they likely swallowed most of their food whole: Sauropods’ teeth had very little wear, unlike those of other herbivorous species, such as the duck-billed dinosaurs, and even mammals. (2,3)They could ‘vacuum up’ a lot of food without having to spend a lot of time chewing.

Some sauropod bones were also filled with air sacs, which could make even larger body sizes mechanically feasible.  (4)This adaptive anatomical feature is found in many birds, dinosaurs’ closest living relatives, and it helps reduce their body weight and promote flight.

Sources: 

1. Baumgart SL, et al. The living dinosaur: accomplishments and challenges of reconstructi.... Biol Lett. 2025;21(5):20250126.

2. Whitlock JA. Inferences of diplodocoid (Sauropoda: Dinosauria) feeding behavior .... PLoS One. 2011;6(4):e18304.

3. Fiorillo AR. Dental micro wear patterns of the sauropod dinosaurs camarasaurus a.... Hist Biol. 1998;13(1):1-16.

4. Wedel MJ. Evidence for bird-like air sacs in saurischian dinosaurs. J Exp Zool A Ecol Genet Physiol. 2009;311(8):611-628.

5. https://www.the-scientist.com/why-were-dinosaurs-so-big-73254?utm_c...

Comment by Dr. Krishna Kumari Challa 20 hours ago

Exercise intensity could be impacting your gut

While exercise is great for both your mental and physical health, new research from Edith Cowan University (ECU) has found that exercise intensity could result in changes to the internal gut biome.

Researchers undertook research into the impact of high and low training loads on athletes, in the hope of assisting athletes to improve their overall health, well-being and performance by better understanding the gut microbiome.

It appears that athletes have a different gut microbiota when compared with the general population. This includes greater total short chain fatty acid concentrations, alpha diversity, an increased abundance of some bacteria and a lower abundance of others.

 while the differing microbiome between athletes and the public could likely be due to the differences in their dietary intake , fitness markers, which include oxygen uptake, have also been correlated.

Published in the Journal of the International Society of Sports Nutrition, this research uncovered that training load had an influence on gut health markers in athletes, with differences detected in short-chain fatty acid concentrations and the abundance of specific bacteria.

 One of the potential reasons for the change in the gut could be the higher levels of blood lactate which results from higher intensity training. The lactate produced in muscle is transported to the gut to be metabolized, which could potentially result in increased bacteria in the gut.

The changes found in the gut biome when comparing high training loads to low training loads, were also related to diet.

Another observation made during the research was the significant slowing of gut transit times in athletes during low training loads. That slowing of transit time during the low training load appears to also be impacting the gut microbiome for an athlete.

The gut may play a role in lactate metabolism and regulating pH levels, both of which could impact performance and overall athlete health, say the researchers. 

B. Charlesson et al, Training load influences gut microbiome of highly trained rowing athletes, Journal of the International Society of Sports Nutrition (2025). DOI: 10.1080/15502783.2025.2507952

Comment by Dr. Krishna Kumari Challa 21 hours ago

Positive emotional bias could be an early sign of cognitive decline in aging populations

As people age, they display a bias in recognizing emotions as positive—to the point of improperly labeling neutral or negative emotions as positive.

Some researchers theorize this bias is an adaptive mechanism to support mental and emotional wellness, but new evidence suggests it may be a sign of cognitive decline.

In a JNeurosci paper, researchers advance understanding of what this positive emotional bias that elders exhibit signifies about their brains' health.

A large pool of participants (665) viewed faces in an emotion recognition task. Age-related positivity bias correlated with poorer cognitive performance in two assessments, but not necessarily emotional decline as measured by examining nonclinical depressive symptoms.

The researchers also observed structural changes in brain areas associated with emotional processing and changes in how these areas communicate to another brain region involved in social decisions. Thus, positivity bias from aging impacts the brain in observable ways that could be leveraged clinically to detect early rising signs of age-related neurodegeneration and cognitive decline.

Researchers are now  exploring how these findings relate to older adults with early cognitive decline, particularly those showing signs of apathy, which is often another early sign of dementia.

 Age-Related Positivity Bias in Emotion Recognition is Linked to Lower Cognitive Performance and Altered Amygdala–Orbitofrontal Connectivity, JNeurosci (2025). DOI: 10.1523/JNEUROSCI.0386-25.2025

Comment by Dr. Krishna Kumari Challa on Tuesday

Kidney fibrosis linked to molecule made by gut bacteria

A molecule made by bacteria in the gut can hitch a ride to the kidneys, where it sets off a chain reaction of inflammation, scarring and fibrosis—a serious complication of diabetes and a leading cause of kidney failure—according to a new study from researchers .

After finding high levels of corisin—a small peptide produced by Staphylococcus bacteria in the gut—in the blood of patients with diabetic kidney fibrosis, the researchers used computer simulations and tissue and mouse experiments to track how corisin affects the kidneys, how it gets there from the gut, and a possible method of countering it with antibody treatment.

These  new findings suggest corisin is indeed a hidden culprit behind progressive kidney damage in diabetes, and that blocking it could offer a new way to protect kidney health in patients.

Taro Yasuma et al, Microbiota-derived corisin accelerates kidney fibrosis by promoting cellular aging, Nature Communications (2025). DOI: 10.1038/s41467-025-61847-2

Comment by Dr. Krishna Kumari Challa on Tuesday

Cells from the spleen found to play a surprising role after heart attack

After a person survives a heart attack, the heart has a brief window of time in which it can heal if the right circumstances exist. But most of the time, scar tissue forms in the areas that lacked oxygen during the heart attack. This scar tissue impairs heart function, which can worsen into heart failure, reducing quality of life and increasing the risk of early death.

A new study has identified a surprising role for the spleen—a small organ near the ribs that filters blood and fights infections—in helping the heart heal after a heart attack.

The research, published in Circulation, demonstrated in mice that specific immune cells called marginal metallophilic macrophages, which originate in the spleen, travel from the spleen to the heart and support a healing response after a heart attack.

Using mouse models, single-cell RNA sequencing and other advanced techniques, the researchers established that these specialized macrophages from the spleen help clear damaging immune cells, suppress inflammation and activate genes that help repair the injured cardiac tissue following a heart attack.

To assess whether the same thing occurs in humans, the researchers measured levels of marginal metallophilic macrophages in blood samples collected from people upon their hospital admission due to a heart attack. The researchers compared these levels with those of cardiac patients who had coronary artery disease but had not recently had a heart attack. The researchers  found that levels of the specialized macrophages were higher in patients who had just had a heart attack.

The researchers also demonstrated that they could boost the numbers of these specialized immune cells in mice with an experimental drug, and that doing so improved the healing and anti-inflammatory effects. This medical intervention is not yet in clinical trials, but it suggests a possible future cardiac immunotherapy targeting the spleen to prevent heart failure in patients who survive a heart attack.

 Mohamed Ameen Ismahil et al, Splenic CD169⁺Tim4⁺ Marginal Metallophilic Macrophages Are Essential for Wound Healing After Myocardial Infarction, Circulation (2025). DOI: 10.1161/CIRCULATIONAHA.124.071772

Comment by Dr. Krishna Kumari Challa on Tuesday

This human type, which the researchers called "Nesher Ramla Homo" (after the archaeological site near the Nesher Ramla factory where it was found), encountered Homo sapiens groups that began leaving Africa about 200,000 years ago, and according to the current study's findings, interbred with them.

The child from the Skhul Cave is the earliest fossil evidence in the world of the social and biological ties forged between these two populations over thousands of years. The local Neanderthals eventually disappeared when they were absorbed into the Homo sapiens population, much like the later European Neanderthals.

The researchers reached these conclusions after conducting a series of advanced tests on the fossil.
The fossil they studied is the earliest known physical evidence of mating between Neanderthals and Homo sapiens.
The current study reveals that at least some of the fossils from the Skhul Cave are the result of continuous genetic infiltration from the local—and older—Neanderthal population into the Homo sapiens population.

Bastien Bouvier et al, A new analysis of the neurocranium and mandible of the Skhūl I child: Taxonomic conclusions and cultural implications, L'Anthropologie (2025). DOI: 10.1016/j.anthro.2025.103385

Part 2

Comment by Dr. Krishna Kumari Challa on Tuesday

Earliest evidence discovered of interbreeding between Homo sapiens and Neanderthals

An international study by researchers provides the first scientific evidence that Neanderthals and Homo sapiens had biological and social relations, and even interbred for the first time, in the Land of Israel.

The research team found a combination of Neanderthal and Homo sapiens traits in the skeleton of a five-year-old child discovered about 90 years ago in the Skhul Cave on Mount Carmel. The fossil, estimated to be about 140,000 years old, is the earliest human fossil in the world to display morphological features of both of these human groups, which until recently were considered two separate species.

Genetic studies over the past decade have shown that these two groups exchanged genes.

Even today, 40,000 years after the last Neanderthals disappeared, part of our genome—2% to 6%—is of Neanderthal origin. But these gene exchanges took place much later, between 60,000 to 40,000 years ago.

In the new study, the researchers were dealing with a human fossil that is 140,000 years old. They  show that the child's skull, which in its overall shape resembles that of Homo sapiens—especially in the curvature of the skull vault—has an intracranial blood supply system, a lower jaw, and an inner ear structure typical of Neanderthals.

For years, Neanderthals were thought to be a group that evolved in Europe, migrating to the Land of Israel only about 70,000 years ago, following the advance of European glaciers.

Part 1

• ‹ Previous
• 1
• 2
• 3
• …
• 1102
• Next ›
• Page