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Comment by Dr. Krishna Kumari Challa on September 9, 2025 at 6:03am

Scientists discover why the flu is more deadly for older people

Scientists have discovered why older people are more likely to suffer severely from the flu, and can now use their findings to address this risk.

In a study published in PNAS, experts discovered that older people produce a glycosylated protein called apolipoprotein D (ApoD), which is involved in lipid metabolism and inflammation, at much higher levels than in younger people. This has the effect of reducing the patient's ability to resist virus infection, resulting in a more serious disease outcome.

ApoD is therefore a target for therapeutic intervention to protect against severe influenza virus infection in the elderly which would have a major impact on reducing morbidity and mortality in the aging population.

ApoD mediates age-associated increase in vulnerability to influenza virus infection, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2423973122

Comment by Dr. Krishna Kumari Challa on September 9, 2025 at 5:58am

Researchers examined how strongly neurons fired just before each choice and how variable that activity was across trials. Variability served as "neural noise." Computational models estimated how closely choices followed expected value and how much they reflected overall uncertainty.

Results showed more exploration in loss trials than in gain trials. After people learned which option was better, exploration stayed higher in loss trials and accuracy fell more from its peak.

Pre-choice firing in the amygdala and temporal cortex rose before exploratory choices in both gain and loss, indicating a shared, valence-independent rate signal. Loss trials also showed noisier amygdala activity from cue to choice.

More noise was linked to higher uncertainty and a higher chance of exploring, and noise declined as learning progressed. Using the measured noise levels in decision models reproduced the extra exploration seen in loss trials. Loss aversion did not explain the gap.
Researchers report two neural signals that shape exploration. A valence-independent firing-rate increase in the amygdala and temporal cortex precedes exploratory choices in both gain and loss. A loss-specific rise in amygdala noise raises the odds of exploration under potential loss, scales with uncertainty, and wanes as learning accrues.

Behavioral modeling matches this pattern, with value-only rules fitting gain choices and value-plus-total-uncertainty rules fitting loss choices. Findings point to neural variability as a lever that tilts strategy toward more trial-and-error when loss looms, while causal tests that manipulate noise remain to be done.

From an evolutionary survival perspective, the strategy fits well with the need to seek out new resources when facing the loss of safe or familiar choices. While one might consider trying a new restaurant at any time, true seeking behavior will become a priority if the favorite location is closed for remodeling.

Tamar Reitich-Stolero et al, Rate and noise in human amygdala drive increased exploration in aversive learning, Nature (2025). DOI: 10.1038/s41586-025-09466-1

Part 2

Comment by Dr. Krishna Kumari Challa on September 9, 2025 at 5:56am

Human brains explore more to avoid losses than to seek gains

Researchers traced a neural mechanism that explains why humans explore more aggressively when avoiding losses than when pursuing gains. Their work reveals how neuronal firing and noise in the amygdala shape exploratory decision-making.

Human survival has its origins in a delicate balance of exploration versus exploitation. There is safety in exploiting what is known, the local hunting grounds, the favorite foraging location, the go-to deli with the familiar menu. Exploitation also involves the risk of over-reliance on the familiar to the point of becoming too dependent upon it, either through depletion or a change in the stability of local resources.

Exploring the world in the hope of discovering better options has its own set of risks and rewards. There is the chance of finding plentiful hunting grounds, alternative foraging resources, or a new deli that offers a fresh take on old favorites. And there is the risk that new hunting grounds will be scarce, the newly foraged berries poisonous, or that the meal time will be ruined by a deli that disappoints.

Exploration-exploitation (EE) dilemma research has concentrated on gain-seeking contexts, identifying exploration-related activity in surface brain areas like cortex and in deeper regions such as the amygdala. Exploration tends to rise when people feel unsure about which option will pay off.

Loss-avoidance strategies differ from gain-seeking strategies, with links to negative outcomes such as PTSD, anxiety and mood disorders.

In the study, "Rate and noise in human amygdala drive increased exploration in aversive learning," published in Nature, researchers recorded single-unit activity to compare exploration during gain versus loss learning.

Part 1

Comment by Dr. Krishna Kumari Challa on September 8, 2025 at 12:57pm

Electrical stimulation can reprogram immune system to heal the body faster

Scientists  have discovered that electrically stimulating macrophages—one of the immune systems key players—can reprogram them in such a way as to reduce inflammation and encourage faster, more effective healing in disease and injury.

This breakthrough uncovers a potentially powerful new therapeutic option, with further work ongoing to delineate the specifics.

Macrophages are a type of white blood cell with several high-profile roles in our immune system. They patrol around the body, surveying for bugs and viruses, as well as disposing of dead and damaged cells, and stimulating other immune cells—kicking them into gear when and where they are needed.

However, their actions can also drive local inflammation in the body, which can sometimes get out of control and become problematic, causing more damage to the body than repair. This is present in lots of different diseases, highlighting the need to regulate macrophages for improved patient outcomes.

In the study, published in the journal Cell Reports Physical Science, the researchers worked with human macrophages isolated from healthy donor blood samples. 

They stimulated these cells using a custom bioreactor to apply electrical currents and measured what happened.

The scientists discovered that this stimulation caused a shift of macrophages into an anti-inflammatory state that supports faster tissue repair; a decrease in inflammatory marker (signaling) activity; an increase in expression of genes that promote the formation of new blood vessels (associated with tissue repair as new tissues form); and an increase in stem cell recruitment into wounds (also associated with tissue repair).

 Electromodulation of human monocyte-derived macrophages drives a regenerative phenotype and impedes inflammation, Cell Reports Physical Science (2025). DOI: 10.1016/j.xcrp.2025.102795. www.cell.com/cell-reports-phys … 2666-3864(25)00394-7

Comment by Dr. Krishna Kumari Challa on September 7, 2025 at 10:27am

The two species diverged from each other more than 5 million years ago, and yet today, M. structor is a sort of parasite living in the queen's colony. But she is hardly a victim.

The Iberian harvester queen ant controls what happens to the DNA of her clones. When she reproduces, she can do so asexually, producing a clone of herself. She can also fertilize her egg with the sperm of her own species or M. structor, or she can 'delete' her own nuclear DNA and use her egg as a vessel solely for the DNA of her male M. structor clones.
This means her offspring can either be related to her, or to another species. The only similarity is that both groups contain the queen's mitochondrial DNA. The result is greater diversity in the colony without the need for a wild neighboring species to mate with.

It also means that Iberian harvester ants belong to a 'two-species superorganism' – which the researchers say "challenges the usual boundaries of individuality."

The M. structor males produced by M. ibericus queens don't look exactly the same as males produced by M. structor queens, but their genomes match.

https://www.nature.com/articles/s41586-025-09425-w

Part 2

Comment by Dr. Krishna Kumari Challa on September 7, 2025 at 10:26am

Ant Queens Produce Offspring of Two Different Species

Some ant queens can produce offspring of more than one species – even when the other species is not known to exist in the nearby wild.

No other animal on Earth is known to do this, and it's hard to believe.

This is bizarre story of a system that allows things to happen that seem almost unimaginable.

Some queen ants are known to mate with other species to produce hybrid workers, but Iberian harvester ants (Messor ibericus) on the island of Sicily go even further, blurring the lines of species-hood. These queens can give birth to cloned males of another species entirely (Messor structor), with which they can mate to produce hybrid workers.

Their reproductive strategy is akin to "sexual domestication", the researchers say. The queens have come to control the reproduction of another species, which they exploited from the wild long ago – similar to how humans have domesticated dogs.

In the past, the Iberian ants seem to have stolen the sperm of another species they once depended on, creating an army of male M. structor clones to reproduce with whenever they wanted.

According to genetic analysis, the colony's offspring are two distinct species, and yet they share the same mother.

Some are the hairy M. ibericus, and the others the hairless M. structor – the closest wild populations of which live more than a thousand kilometers away.

The queen can mate with males of either species in the colony to reproduce. Mating with M. ibericus males will produce the next generation of queen, while mating with M. structor males will result in more workers. As such, all workers in the colony are hybrids of M. ibericus and M. structor.

Part 1

Comment by Dr. Krishna Kumari Challa on September 6, 2025 at 10:13am

Physicists create a new kind of time crystal that humans can actually see

Imagine a clock that doesn't have electricity, but its hands and gears spin on their own for all eternity. In a new study, physicists  have used liquid crystals, the same materials that are in your phone display, to create such a clock—or, at least, as close as humans can get to that idea. The team's advancement is a new example of a "time crystal." That's the name for a curious phase of matter in which the pieces, such as atoms or other particles, exist in constant motion.

The researchers aren't the first to make a time crystal, but their creation is the first that humans can actually see, which could open a host of technological applications. They can be observed directly under a microscope and even, under special conditions, by the naked eye.

In the study, the researchers designed glass cells filled with liquid crystals—in this case, rod-shaped molecules that behave a little like a solid and a little like a liquid. Under special circumstances, if you shine a light on them, the liquid crystals will begin to swirl and move, following patterns that repeat over time.

Time Crystal in motion

Under a microscope, these liquid crystal samples resemble psychedelic tiger stripes, and they can keep moving for hours—similar to that eternally spinning clock.

Hanqing Zhao et al, Space-time crystals from particle-like topological solitons, Nature Materials (2025). DOI: 10.1038/s41563-025-02344-1

Comment by Dr. Krishna Kumari Challa on September 6, 2025 at 9:57am

Macaws learn by watching interactions of others, a skill never seen in animals before

One of the most effective ways we learn is through third-party imitation, where we observe and then copy the actions and behaviors of others. Until recently, this was thought to be a unique human trait, but a new study published in Scientific Reports reveals that macaws also possess this ability.

Second-party imitation is already known to exist in the animal kingdom. Parrots are renowned for their ability to imitate human speech and actions, and primates, such as chimpanzees, have learned to open a puzzle box by observing a human demonstrator. But third-party imitation is different because it involves learning by observing two or more individuals interact rather than by direct instruction.

Scientists chose blue-throated macaws for this study because they live in complex social groups in the wild, where they need to learn new behaviors to fit in quickly. Parrots, like macaws, are also very smart and can do things like copy sounds and make tools.

To find out whether macaws could learn through third-party imitation, researchers worked with two groups of them, performing more than 4,600 trials. In the test group, these birds watched another macaw perform one of five different target actions in response to a human's hand signals. These were fluffing up feathers, spinning its body, vocalizing, lifting a leg or flapping its wings. In the control group, macaws were given the same hand signals without ever seeing another bird perform the actions.

The results were clear. The test group learned more actions than the control group, meaning the interactions between the single macaw and the human experimenter helped them learn specific behaviors. They also learned these actions faster and performed them more accurately than the control group. The study's authors suggest that this ability to learn from passively observing two or more individuals helps macaws adapt to new social situations and may even contribute to their own cultural traditions.

The research shows that macaws aren't just smart copycats. They may also have their own complex social lives and cultural norms, similar to humans.

Esha Haldar et al, Third-party imitation is not restricted to humans, Scientific Reports (2025). DOI: 10.1038/s41598-025-11665-9

Comment by Dr. Krishna Kumari Challa on September 5, 2025 at 1:18pm

Is this the future of food? 'Sexless' seeds that could transform farming
Scientists are tinkering with plant genes to create crops that seed their own clones, with a host of benefits for farmers.
Sacks of seeds without the sex
Agriculture is on the brink of a revolution: grain crops that produce seeds asexually. The technology — trials of which could start sprouting as early as next month — exploits a quirk of nature called apomixis, in which plants create seeds that produce clones of the parent. Apomixis could slash the time needed to create new varieties of crops, and give smallholder farmers access to affordable high-yielding sorghum (Sorghum bicolor) and cowpea (Vigna unguiculata). But before self-cloning crops can be commercialized, the technology must run the regulatory gauntlet.

https://www.nature.com/articles/d41586-025-02753-x?utm_source=Live+...

Comment by Dr. Krishna Kumari Challa on September 5, 2025 at 12:34pm

After early-life stress, astrocytes can affect behaviour

Astrocytes in the lateral hypothalamus region of the brain, an area involved in the regulation of sleep and wakefulness, play a key role in neuron activity in mice and affect their behavior,  researchers have found.

By broadening medical science's understanding of cerebral mechanisms, the discovery could someday help in the treatment and prevention of depression in humans, the researchers say.

According to the scientific literature, early-life stress leads to a five-fold increase in the risk of developing a mental-health disorder as an adult, notably causing treatment-resistant disorders.

As brain cells, astrocytes are sensitive to variations in the blood concentration of metabolites and, in response to changes in the blood, astrocytes can modulate the extent of their interaction with neurons, their neighboring cells.

In mice, those changes are particularly responsive to the level of corticosterone, the stress hormone in the rodents' blood.

In adult mice who experienced early-life stress, researchers saw abnormally high levels of corticosterone. The impact of stress on behavior also differed according to sex. Females were less active at night, while males were hyperactive during the day.

In people with depression who have experienced a similar type of stress, these sex differences have also been observed.

 Lewis R. Depaauw-Holt et al, A divergent astrocytic response to stress alters activity patterns via distinct mechanisms in male and female mice, Nature Communications (2025). DOI: 10.1038/s41467-025-61643-y

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