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Comment by Dr. Krishna Kumari Challa yesterday

Nature's original bioplastic may have fed animals for hundreds of millions of years

Long before humans discovered biodegradable plastics, microorganisms had already invented their own. Many bacteria and archaea produce natural bioplastics called polyhydroxyalkanoates (PHAs), storing them inside their cells as reserves of carbon and energy.
Until now, scientists thought that only microorganisms themselves could break down these substances. Researchers at the Max Planck Institute for Marine Microbiology in Bremen, Germany, have now overturned that long-standing assumption.

In a study published in Nature Ecology & Evolution, they show that animals ranging from marine worms and starfish to terrestrial species, including earthworms, have enzymes capable of degrading microbial PHAs. The findings reveal a previously overlooked way in which microbial carbon can enter animal food webs.
Microbial PHAs occur naturally in soils, sediments and aquatic environments worldwide. They are produced whenever microorganisms store excess carbon for later use and are among the few naturally occurring plastics that are completely biodegradable. Because PHAs are increasingly manufactured as sustainable alternatives to conventional plastics, understanding how they are degraded in nature has become an important area of research.
The new findings suggest that animals, together with microorganisms, may contribute to the breakdown of these natural bioplastics. More fundamentally, they reveal that animals can exploit a microbial carbon reserve that had previously been thought to be inaccessible to them.

Animal degradation of microbial storage polyhydroxyalkanoates, Nature Ecology & Evolution (2026). DOI: 10.1038/s41559-026-03153-8

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Comment by Dr. Krishna Kumari Challa yesterday

A 236-million-year-old fossil challenges the story of mammalian live birth

Some cynodonts may have been giving birth to live young much sooner in evolutionary history than previously assumed. A new Frontiers in Mammal Science study has offered the first compelling evidence that cynodonts may have been viviparous—a reproductive mode characterized by live birth.

Researchers showed for the first time that live birth was present in at least one mammalian ancestor, Chiniquodon theotonicus, which lived approximately 236 million years ago. This implies that viviparity among early cynodonts originated in the mammalian lineage at least 95 to 90 million years earlier than previously thought.

Cynodonts thrived in the Triassic, a period of recovery and restructuring of ecosystems after one of the most devastating mass extinctions in life history. This meant high competition for resources and strong predatory pressures. Combined with a trend toward aridity and strong seasonality, embryos of viviparous species would be better protected than those of egg-laying species.

Until now, giving birth to live young was considered a relatively modern evolutionary acquisition in the mammalian lineage. The finding raises questions about which other traits believed to have appeared much later were already present among cynodonts, the researchers say.

Early Origin of Viviparity in the Mammalian Lineage, Frontiers in Mammal Science (2026). DOI: 10.3389/fmamm.2026.1845319

Comment by Dr. Krishna Kumari Challa on Thursday

Female gut muscles reshape to meet the demands of reproduction, preclinical study suggests

Organs don't just grow in early life; they can change in response to physiological or environmental challenges in adulthood. Researchers have now identified an active role for the intestinal muscles in remodelling the gut after reproduction.
Reproduction remodels intestinal smooth muscle in female fruit flies and mice, elongating contractile filaments without increasing cell number and reducing contractility. In flies, mating lowers juvenile hormone receptor signalling in muscle, permitting growth, while epithelial growth is promoted by the same hormone. These changes may enhance nutrient absorption during reproduction.

Alessandro Mineo et al, The sex and reproductive plasticity of intestinal muscles instruct gut size, Cell (2026). DOI: 10.1016/j.cell.2026.07.024

Comment by Dr. Krishna Kumari Challa on Thursday

For decades we have known that rheumatoid arthritis selectively targets particular joints, but one of the great unanswered questions is why?
These new findings suggest that the answer lies not only in the immune system but also in the tissues themselves. The cellular and structural characteristics established during development may help determine where inflammation takes hold later in life.
Researchers found that the developing joints were made up mainly of structural cells, including cartilage-forming cells and fibroblasts, rather than immune cells. They then investigated what drives these cells to develop into their different specialized forms.

One population that drew particular attention was the synovial lining fibroblasts. These cells produce substances that lubricate the joint to help protect and maintain smooth movement, yet they can also behave abnormally in arthritis. Further analysis suggested that the lining may come from two different sources, both the cartilage and surrounding joint fibroblasts.

The process appeared to be influenced by specific localized signals such as low oxygen levels. This may provide insights into the mechanisms driving their function and help identify ways to restore their normal protective role in disease.
The researchers found important differences between the PIP and DIP joints. A bespoke image analysis tool showed that PI16+ fibroblasts that were enriched in the PIP joints were specifically located around blood vessels and at sites where tendons and ligaments connect with surrounding tissue.

They also showed that PI16+ fibroblasts responded differently to inflammatory signals compared with other fibroblast populations. While PI16+ fibroblasts shared a common pro-inflammatory response with PI16- fibroblasts, they also displayed distinct changes in pathways linked to tissue organization and immune regulation.

The team also identified striking structural differences between the joints. Using high-resolution 3D imaging at Diamond Light Source at the Harwell Science and Innovation Campus, they found that the synovial tissue surrounding PIP joints was larger and organized differently from that seen in joints that are not usually affected by rheumatoid arthritis. Together, these cellular and structural differences may help explain why inflammation develops in some locations but not others.
Together, the findings suggest that the tendency of rheumatoid arthritis to affect particular joints may be shaped by tissue architecture established during development. Rather than being determined by immune activity alone, vulnerability to inflammation may depend on the local cellular and structural environment of each joint.

Sarah Davidson et al, The embryonic origins of site-specific arthritis, Nature Immunology (2026). DOI: 10.1038/s41590-026-02542-2

Comment by Dr. Krishna Kumari Challa on Thursday

Arthritis origins may begin before birth

Researchers have discovered that some joints may be more susceptible to inflammatory arthritis before birth, offering new insight into why rheumatoid arthritis attacks particular joints while sparing others.
"The embryonic origins of site-specific arthritis", published in Nature Immunology, provides new insight into one of the long-standing mysteries of rheumatoid arthritis: why inflammation targets certain joints while leaving others relatively unaffected.

Rheumatoid arthritis is an autoimmune disease that causes pain, swelling and stiffness when the immune system attacks the synovium, the tissue lining the joints. Over time, this inflammation can damage cartilage, bone and surrounding tissues.

The study compared two finger joints that differ in their susceptibility to rheumatoid arthritis. Researchers compared proximal interphalangeal (PIP) joints, which are commonly affected by the disease, and distal interphalangeal (DIP) joints near the fingertips, which are usually spared.

They found that the PIP joints contained larger synovial volumes and higher levels of PI16-positive (PI16+) fibroblasts, a specialized type of connective tissue cell. These differences were established before birth, suggesting that the tissues themselves may play an important role in determining where disease occurs.

The embryonic origins of site-specific arthritis. Credit: NDORMS

Part 1

Comment by Dr. Krishna Kumari Challa on Thursday

What if there's a star inside a black hole?
A dark-matter halo with an exotic pressure–density relation can mathematically surround a neutron star with an event horizon while leaving the star nonsingular and structured inside. Such configurations exist only within a narrow halo-density range and require dark-matter densities far above expected astrophysical values, so they remain theoretical.

Chen Tan et al, A Neutron Star Hidden Inside a Black Hole, arXiv (2026). DOI: 10.48550/arxiv.2608.06224

Comment by Dr. Krishna Kumari Challa on Thursday

What made the visible-eyes videos different? To answer that question, researchers used EEG readings. The adult speaker's EEG readings were recorded in advance during video production, while the babies wore EEG caps as they watched the videos. Analyzing brain signals allowed researchers to determine the degree of matching between the adult's and baby's brain activity.

Researchers found that adult-to-infant neural coupling—the one-way matching of adult brain waves to infant brain waves—predicted the infants' ability to learn. Only adult→infant neural coupling, not the infants' own rhythmic brain activity, predicted learning ability.

"The key insight," the authors point out, "is that speaker-to-listener neural coupling is a better predictor of selective learning than infants' own neural activity." Statistical tests supported this: Once researchers accounted for the strength of adult-to-infant coupling, the direct effect of gaze on learning essentially vanished. In short, eye contact drove a brain-to-brain signal that explained the learning boost.

Wei Zhang et al, Adult-to-infant unidirectional neural coupling mediates selective social learning in infants from the United Kingdom and Singapore, Nature Communications (2026). DOI: 10.1038/s41467-026-75831-x

Part 2

Comment by Dr. Krishna Kumari Challa on Thursday

Eye contact may help babies learn
Have you ever noticed how babies get hooked the moment someone makes eye contact with them? That eye contact is not only cute; it may also send a powerful message to a baby. For years, scientists have been investigating whether social messages like eye contact and baby talk do more than engage babies. They may help synchronize babies' brains with adult brain waves. But the biggest question remained: Does it actually help babies learn?
A new study, published in Nature Communications, offers an answer. Scientists found that 9-month-old infants were able to learn a novel language when the face in a video looked directly at them with fully visible eyes.

Using electroencephalography, or EEG, brain scanning, scientists detected a kind of "neural handshake" between the adult's and infant's brains, synchronized through eye contact.
The results showed how vital eye contact may be for babies' learning. When the person in the video made eye contact while their eyes were fully visible, the infants succeeded in learning the invented language. They recognized which combinations of sounds formed "words" and demonstrated this understanding by spending more time looking at novel sound combinations than ones they had heard before.
The findings provide support for a key assumption of developmental psychology: "Adults curate infants' information selection through ostensive marking of valuable content using social cues such as eye contact." In other words, adults not only provide information for infants but also help them select what to learn.

However, when the speaker's eyes were partly obscured by dark glasses or entirely covered by opaque ones, the babies did not learn. It was as if the switch for learning was off. This was not because they stopped paying attention; the babies looked at the screen for roughly the same amount of time whether the speaker's eyes were visible or not.

Although their eyes were glued to the screen, hiding the speaker's eyes appeared to "scramble" the message, and the participants did not acquire the new language.

The intriguing pattern held for all infants, regardless of whether they were from Singapore or the UK. Babies in both groups were selective learners only when learning from a speaker making visible eye contact.
Part 1

Comment by Dr. Krishna Kumari Challa on Thursday

Too Cool To Care? Air Conditioning Weakens Climate Action Support: behavioural insulation

Study finds that the more people rely on air conditioning to stay cool, the less likely they are to support broader efforts to cool cities and cut energy use.
As global temperatures rise, air conditioning has become essential to protect people from extreme heat. But a new study has found that widespread reliance on private cooling may be creating a paradox in cities: the more effectively households cool themselves indoors, the less urgency they feel to support the broader climate measures needed to cool cities.
The study has found that households that depend heavily on air conditioning are less likely to adopt energy-saving habits or support community-wide heat mitigation strategies. The findings, published in Sustainable Cities and Society, describe this phenomenon as “behavioural insulation”, where effective indoor cooling dampens the perceived urgency to address heat through collective action.
Heat awareness does not always change behaviour

To explore how people respond to rising temperatures, the researchers analysed survey responses from 967 adults across 416 households in Singapore, together with spatial heat indicators and household electricity consumption records.

The results revealed a clear divide. People who felt more affected by heat were more likely to discuss climate issues and encourage others to act. But this rarely translated into lower household energy use. Those who relied most on air-conditioning tended to consume more electricity and were less likely to adopt energy-saving habits.

One of the key findings is that experiencing heat does not automatically translate into lower-energy behaviour or stronger collective climate action.
The researchers also observed that heavy air-conditioning users showed less support for public heat mitigation measures such as expanding urban greenery, increasing tree cover and improving neighbourhood shading, even while spending more on keeping their own homes cool.
According to the researchers, the findings point to something more systemic than individual indifference — a gradual shift in which widespread private cooling may weaken the behavioural conditions associated with support for collective climate action.
The researchers say they are not arguing against air-conditioning, as cooling is essential for comfort, health and wellbeing. Rather, they argue that cooling should be complemented by urban design strategies which include shading, greening, improved ventilation, reflective building materials and climate-sensitive planning, that reduce outdoor temperatures in the first place.

https://www.sciencedirect.com/science/article/pii/S2210670726003318...

Comment by Dr. Krishna Kumari Challa on Thursday

Growing rice on the moon

The Moon's surface is a tough place to farm. It has no organic material, and the nitrogen sources that plants need, like ammonia and nitrate, are essentially absent.

Scientists in Japan have created a portable plasma device that can turn air into fertilizer, helping rice grow in simulated lunar soil.

It may sound like science fiction, but a team of researchers from Japan have made it possible to harvest fresh rice on lunar soil. 

The researchers developed a portable plasma device that converts ordinary air into nitrogen fertilizer, When applied to soil designed to simulate the Moon's surface, it neutralized the soil's harsh alkalinity and released trapped nutrients like calcium, magnesium and potassium. This enabled the researchers to grow rice seedlings in the lunar soil.

Beyond its off-world potential, the researchers note that their low-power, fossil-fuel-free technology could help make farming on Earth more sustainable too. 

https://www.nature.com/articles/s41526-026-00602-3

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