Bionic hand merges with user's nervous and skeletal systems, remaining functional after years of daily use

A woman's life took a dramatic turn when a farming accident claimed her right arm more than 20 years ago. Since then, she has endured excruciating phantom limb pain.

In addition to her intractable pain, she found that conventional prostheses were uncomfortable and unreliable, and thus of little help in daily life. All this changed when she received groundbreaking bionic technology that allowed her to wear a much more functional prosthesis comfortably all day. The higher integration between the bionics and her residual limb also relieved her pain. 

Mechanical attachment and reliable control are two of the biggest challenges in artificial limb replacement. People with limb loss often reject even the sophisticated prostheses commercially available due to these reasons, after experiencing painful and uncomfortable attachment with limited and unreliable controllability. A multidisciplinary group of engineers and surgeons solved these problems by developing a human–machine interface that allows the prosthesis to be comfortably attached to the user's skeleton via osseointegration, while also enabling electrical connection with the nervous system via electrodes implanted in nerves and muscles. This research is now published in the journal Science Robotics.

 Max Ortiz-Catalan et al, A highly integrated bionic hand with neural control and feedback for use in daily life, Science Robotics (2023). DOI: 10.1126/scirobotics.adf7360. www.science.org/doi/10.1126/scirobotics.adf7360

NASA asteroid sample contains life-critical water and carbon

A sample collected from the 4.5-billion-year-old asteroid Bennu contains abundant water and carbon, NASA revealed on Wednesday, offering more evidence for the theory that life on Earth was seeded from outer space

The discovery follows a seven-year-round-trip to the distant rock as part of the OSIRIS-REx mission, which dropped off its precious payload in the Utah desert last month for painstaking scientific analysis.

"This is the biggest carbon-rich asteroid sample ever returned to Earth," NASA administrator Bill Nelson said at a press event at the Johnson Space Center in Houston, where the first images of black dust and pebbles were revealed.

Carbon accounted for almost five percent of the sample's total weight, and was present in both organic and mineral form, while the water was locked inside the crystal structure of clay minerals, he said.

Scientists think the reason Earth has oceans, lakes and rivers is because it was hit with water-carrying asteroids 4 to 4.5 billion years ago, making it a habitable planet.

All life on Earth meanwhile is based on carbon, which forms bonds with other elements to produce proteins and enzymes as well as the building blocks of genetic code, DNA and RNA.

The findings were made through a preliminary analysis involving scanning electron microscopy, X-ray computed tomography and more.

Research finds commonly-used herbicide is harmful to adolescent brain function

Herbicides are the most used class of pesticides worldwide, with uses in agriculture, homes and industry. Exposures to two of the most popular herbicides were associated with worse brain function among adolescents, according to a study  by researchers.

 Researchers reported measuring metabolite concentrations of two commonly used herbicides—glyphosate and 2,4-dichlorophenoxyacetic acid (2,4D)—and the insect repellent DEET in urine samples collected in 2016 from 519 adolescents, aged 11 to 17, living in the agricultural county of Pedro Moncayo, Ecuador. Researchers also assessed neurobehavioral performance in five areas: attention and inhibitory control, memory and learning, language, visuospatial processing, and social perception.

Many chronic diseases and mental health disorders in adolescents and young adults have increased over the last two decades worldwide, and exposure to neurotoxic contaminants in the environment could explain a part of this increase, according to the researchers. 

Part 1

Among the findings:

• Glyphosate, a nonselective herbicide used in many crops, including corn and soy, and for vegetation control in residential settings, was detected in 98% of participants.
• 2,4D, a broadleaf herbicide used on lawns, aquatic sites, and agricultural crops, was detected in 66% of participants.
• Higher amounts of 2,4D in urine were associated with lower neurobehavioral performance in the domains of attention and inhibitory control, memory and learning, and language.
• Glyphosate concentration in urine was associated with lower scores in social perception only, while DEET metabolites were not associated with neurobehavioral performance.

Following the introduction of genetically modified, glyphosate-resistant "Roundup-ready" crops in 1996 and 2,4D resistant crops in 2014, there have been substantial increases in glyphosate and 2,4D use, making them the most widely used herbicides in the world, they wrote in a published paper.

Briana Chronister et al, Urinary glyphosate, 2,4-D and DEET biomarkers in relation to neurobehavioral performance in Ecuadorian adolescents in the ESPINA cohort, Environmental Health Perspectives (2023). DOI: 10.1289/EHP11383

Part 2

Birds disperse eaten insects' eggs

Relationship patterns among flightless stick insects suggest that birds disperse the eggs after eating gravid females. Now this is shown to be true in a new study.

 Most species of stick insects are flightless, yet they are distributed over wide distances and across geographical features that would impede the expansion of flightless animals. This has caused researchers to think that their eggs might be dispersed by birds feeding on gravid females, much in the same way as many plant species rely on birds eating their seeds together with fruits and dispersing them while the seeds pass through the digestive tracts of the birds unharmed.

Experimental studies with Ramulus mikado, a common stick insect in Japan, had suggested that this is possible, but since direct observation of such an event in nature is highly unlikely, it has been unclear whether this mechanism actually contributes to the distribution of the insect.

So researchers turned to the analysis of the relationship patterns of Ramulus mikado populations. They made use of the idea of genetic isolation by geographic distance. 

According to this idea, when individual dispersal distances are smaller, such as in flightless insects, the accumulation of genetic mutations eventually leads to a positive correlation between genetic differentiation among locations and the geographic distance that separates them. Thus, the genetic variation between different populations can be a proxy for the species' rate of dispersal.

The results, published in the journal Proceedings of the Royal Society B, paint a vivid picture. Among many genes where the differences correlated with the geographic distance, the team found a few examples of genes that were clearly closely related even though they were geographically separated by up to hundreds of kilometers and across geographic features that these animals usually cannot overcome.

Astonishingly, amidst a sea of limited active dispersal, they discovered identical genotypes jumping across vast distances, strongly indicating the past occurrence of passive long distance genetic dispersal.

In other words, a few of the flightless insects must have flown from place to place, and the only plausible way in which this could happen is that the eggs of the insects survive the passage through the digestive tract of birds that eat them.

And the insect eggs were seen in bird faeces. 

Part 1

Why this type of dispersal not seen among other insects? 

The eggs of most insect species are typically fertilized just before being laid, relying on sperm stored within the female insects after copulation. However, in some stick insect species, females are parthenogenic, that is, they can produce viable eggs without fertilization. It is only because of this quirk in their nature that viable stick insect babies can hatch from the eggs.

Suetsugu Kenji et al, Phylogeographical evidence for historical long-distance dispersal in the flightless stick insect Ramulus mikado, Proceedings of the Royal Society B: Biological Sciences (2023). DOI: 10.1098/rspb.2023.1708. royalsocietypublishing.org/doi … .1098/rspb.2023.1708

Part 2

Gene editing makes chickens flu-resistant

Bird-flu-resistant chickens have been created using CRISPR gene editing. When exposed to the flu virus, nine out of ten of the animals remained uninfected and didn’t pass the virus to other birds. Researchers modified a gene encoding a chicken protein that the virus needs to replicate. But this prompted the virus to start replicating using other proteins in the same family, which the researchers think could be addressed with more edits. “We must be careful not to facilitate adaptations of the virus that make it more dangerous than it [already] is,” says virologist and study co-author Wendy Barclay.

https://english.elpais.com/science-tech/2023-10-10/the-same-lab-tha...

https://www.nature.com/articles/s41467-023-41476-3.epdf?sharing_tok...

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Simulations of 'backwards time travel' can improve scientific experiments

Physicists have shown that simulating models of hypothetical time travel can solve experimental problems that appear impossible to solve using standard physics.

If gamblers, investors and quantum experimentalists could bend the arrow of time, their advantage would be significantly higher, leading to significantly better outcomes. Researchers at the University of Cambridge have shown that by manipulating entanglement—a feature of quantum theory that causes particles to be intrinsically linked—they can simulate what could happen if one could travel backwards in time. So that gamblers, investors and quantum experimentalists could, in some cases, retroactively change their past actions and improve their outcomes in the present. Whether particles can travel backwards in time is a controversial topic among physicists, even though scientists have previously simulated models of how such spacetime loops could behave if they did exist. By connecting their new theory to quantum metrology, which uses quantum theory to make highly sensitive measurements, the Cambridge team has shown that entanglement can solve problems that otherwise seem impossible.

 David R. M. Arvidsson-Shukur et al, Nonclassical Advantage in Metrology Established via Quantum Simulations of Hypothetical Closed Timelike Curves, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.150202

Study finds we can respond to verbal stimuli while sleeping

Sleep is not a state in which we are completely isolated from our environment: while we sleep, we are capable of hearing and understanding words. These observations, the result of close collaboration between various research teams call into question the very definition of sleep and the clinical criteria that make it possible to distinguish between its different stages.

Sleep is generally defined as a period during which the body and mind are at rest—as if disconnected from the world. However, a new study shows that the frontier between wakefulness and sleep  is much more porous than it seems.

The researchers have shown that ordinary sleepers can pick up verbal information transmitted by a human voice and respond to it by contracting their facial muscles. This astonishing ability occurs intermittently during almost all stages of sleep—like windows of connection with the outside world were temporarily opened on this occasion. These new findings suggest that it may be possible to develop standardized communication protocols with sleeping individuals to understand better how mental activity changes during sleep. On the horizon: a new tool to access the cognitive processes that underlie both normal and pathological sleep.

Part 1

Even if it seems familiar because we indulge in it every night, sleep is a highly complex phenomenon. Our research has taught us that wakefulness and sleep are not stable states: on the contrary, we can describe them as a mosaic of conscious and seemingly unconscious moments. It is essential to decipher the brain mechanisms underlying these intermediate states between wakefulness and sleep. "When they are dysregulated, they can be associated with disorders such as sleepwalking, sleep paralysis, hallucinations, the feeling of not sleeping all night, or on the contrary of being asleep with your eyes open.

To distinguish between wakefulness and the different stages of sleep, researchers usually use physiological indicators such as specific brain waves made visible through electroencephalography. Unfortunately, these indicators do not provide a detailed picture of what is happening in the minds of sleepers; sometimes, they even contradict their testimonies.

Part 2

To explore this avenue, the researchers recruited 22 people without sleep disorders and 27 patients with narcolepsy—that is, people who experience uncontrollable episodes of daytime sleepiness. People with narcolepsy have the particularity of having many lucid dreams,  in which they are aware of being asleep; some can sometimes even shape their dream scenario as they wish.

In addition, they easily and quickly enter REM sleep (the stage where lucid dreaming occurs) during the day, making them good candidates for studying consciousness during sleep under experimental conditions.

Participants in the study were asked to take a nap. The researchers gave them a "lexical decision" test, in which a human voice pronounced a series of real and made-up words. Participants had to react by smiling or frowning to categorize them into one or the other of these categories. Throughout the experiment, they were monitored by polysomnography—a comprehensive recording of their brain and heart activity, eye movements, and muscle tone.

Upon waking up, participants had to report whether they had or had not had a lucid dream during their nap and whether they remembered interacting with someone.

Most of the participants, whether narcoleptic or not, responded correctly to verbal stimuli while remaining asleep. These events were certainly more frequent during lucid dreaming episodes, characterized by a high level of awareness. 

By cross-referencing these physiological and behavioral data and the participants' subjective reports, the researchers also showed that it is possible to predict the opening of these windows of connection with the environment, i.e., the moments when sleepers were able to respond to stimuli. They were announced by an acceleration in brain activity and by physiological indicators usually associated with rich cognitive activity.

Türker B. et al. Behavioral and brain responses to verbal stimuli reveal transient periods of cognitive integration of the external world during sleep. Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01449-7. www.nature.com/articles/s41593-023-01449-7

Part 3

Restoring nerve-muscle connections boosts strength of aging mice, study finds

A small molecule previously shown to enhance strength in injured or old laboratory mice does so by restoring lost connections between nerves and muscle fibers,  researchers have found.

The molecule, called PGE2, blocks the activity of an aging-associated enzyme, or gerozyme, called 15-PGDH that naturally increases in muscles as they age. The study showed that levels of the gerozyme increase in muscles after nerve damage and that it is prevalent in muscle fibers of people with neuromuscular diseases. The research is the first to show that damaged motor neurons—nerves connecting the spinal cord to muscles—can be induced to regenerate in response to a drug treatment and that lost strength and muscle mass can be at least partially regained. It suggests that, if similar results are seen in humans, the drug may one day be used to prevent muscle loss of muscle strength due to aging or disease or to hasten recovery from injury.

 Mohsen A. Bakooshli et al, Regeneration of neuromuscular synapses after acute and chronic denervation by inhibiting the gerozyme 15-prostaglandin dehydrogenase, Science Translational Medicine (2023). DOI: 10.1126/scitranslmed.adg1485

Large trial shows taking less blood for lab testing reduces transfusions in intensive care

A world-first clinical trial published in JAMA could provide an easy way to save tens of thousands of units of blood every year worldwide.

The trial, which involved more than 27,000 patients in 25 adult intensive care units (ICUs) across Canada, showed that taking less blood for lab tests using "small-volume" tubes reduced the need for almost one blood transfusion for every 10 patients. Most hospitals use standard tubes that automatically draw four to six milliliters (ml) of blood, but a typical laboratory test requires less than 0.5 ml of blood, meaning the rest (more than 90%) is wasted. Commercially available small-volume tubes have a weaker vacuum inside that automatically draws up to half as much blood. "While the amount of blood drawn per tube is relatively small, ICU patients typically require multiple blood samples taken multiple times every day. This can add up to significant blood loss that contributes to anemia, or low red blood cells. ICU patients are unable to produce more red blood cells to correct for this blood loss and often require treatment with a blood transfusion.

This trial showed that we can save one blood transfusion for every 10 ICU patients by simply switching to small-volume tubes for blood collection.

At a time when everyone is trying to find ways to make health care more sustainable, and preserve our supply of blood products, this study provides a simple solution that can be implemented without additional cost or negative effects. The study also has important implications for patients, as low red blood cells (anemia) can leave patients feeling tired and weak and is associated with can lead to other complications and longer hospital stays. While blood transfusions can usually correct anemia, there can be rare side effects, such as difficulty breathing, allergic reactions and infections.
Part 1

By the numbers

• 97: Percentage of patients who develop anemia after eight days in the ICU
• 50: Percentage of transfusions given in the ICU in the absence of active bleeding
• 41: Amount of blood (in ml) taken per ICU patient per day for routine blood tests (equivalent of one full blood donation every eight days)
• 75: Percentage of patients who receive at least one blood transfusion within seven days of ICU admission (40% of all ICU patients)
• $450: Cost per unit of blood in Canada (not including indirect costs associated with testing, preparation, storage, administration, reactions)
• 90: Percentage of blood that is wasted in routine lab tests
• 10: Units of blood that could be saved per 100 patients with ICU stays of more than 48 hours if the results of this study were implemented

Monkey lives with gene-edited pig kidney A macaque lived for more than two years with a kidney from a gene-edited miniature pig — one of the longest-lasting interspecies organ transplants. It raises hopes that human organ shortages could one day be alleviated by using organs from donor animals. The donor pigs received 69 gene edits to prevent immune reactions after transplantation and to keep the organ healthy. Of the 15 monkeys that received a transplant, five survived for more than one year and one of those lived for 758 days.

https://www.nature.com/articles/s41586-023-06594-4.epdf?sharing_tok...

Hair Turns Gray Due to Stuck Stem Cells

Hair-colouring stem cells must swing back and forth between their maturity states to give hair its colour.

Like human aging, stem cell maturation is considered a one-way process; once an undifferentiated stem cell goes down the path to become a specific type of cell, there is no turning back. But that does not seem to be the case with melanocyte stem cells (McSC), which give rise to cells that produce hair and skin pigments. 

In a recent study, researchers investigated McSC in hair follicles and found that depending on microenvironment cues, McSCs can fluctuate between undifferentiated and differentiated states. The researchers also found that as the hair follicle ages, a larger number of melanocyte stem cells get stuck in an undifferentiated state, losing their ability to mature and produce melanin. Published in Nature, these results not only challenge the traditional view on how stem cells differentiate, but also offer clues to why hair turns gray with aging. 

The researchers were surprised to find that McSC did not reside in an area called the bulge as previously thought, but were instead located in a compartment known as the hair germ. When the hair started to grow, the McSC transitioned to an intermediate differentiation state from which they either transformed into fully mature melanocytes at the base of the growing hair or moved up to the hair bulge where they stayed as undifferentiated cells. Then these stem cells homed back to the hair germ as the hair entered the resting phase of its growth cycle.

Once they realized that the maturation of these cells depended on their location, the team next investigated which signals within those compartments drove these changes. In the new study, the team found that nearby epithelial cells in the hair germ released Wnt ligands that mature the McSC, but these signals were suppressed in the bulge where the cells regained their undifferentiated features.

Melanocytes give hair its color, and hair pigmentation reduces with aging. So, the researchers wondered what would happen to McSC mobility in an aged hair follicle. To accelerate the aging of hair follicles, the researchers plucked mouse hair to induce regeneration of the follicles and observed McSCs over time. In aged mice, they found more of the stem cells in the bulge area rather than going back to the hair germ.

These findings suggested that as the hair follicle ages, McSC get stuck in a region where less pigment-inducing signals are present. This mechanism might explain why hair turns gray much more rapidly than it falls off.

Although scientists knew that cells could swing back and forth between their maturity states when there were tissue injuries, the study results are exciting as they reveal that dedifferentiation can also occur under a physiological condition.

Since the researchers conducted all of the experiments in mice, questions remain as to whether the same events are also seen in humans.

Sun Q, et al. Dedifferentiation maintains melanocyte stem cells in a dynamic niche. Nature. 2023;616(7958):774-782.

Rabbani P, et al. Coordinated activation of Wnt in epithelial and melanocyte stem cel.... Cell. 2011;145(6):941-955.

Research shows wildfire smoke may linger in homes long after initial blaze

Newly published research on indoor air quality  shows wildfire smoke may linger in homes long after the initial blaze has been put out or winds have shifted.

The findings, published in Science Advances, show that wildfire smoke can attach to home surfaces like carpet, drapes or counters—extending the exposure for those inside and potentially causing health problems even after an initial cleaning activity by air purifiers.

However, the research also shows that  surface cleaning—like vacuuming, dusting or mopping—can reduce exposure and limit risk. The team was able to show that the amount of smoke left on surfaces was proportional to the surface area that was cleaned. That means simple cleaning and specifically addressing large but little noticed spaces that may trap harmful compounds such as cabinets and HVAC systems could be beneficial right away.

 Jienan Li et al, The persistence of smoke VOCs indoors: partitioning, surface cleaning, and air cleaning in a smoke-contaminated house, Science Advances (2023). DOI: 10.1126/sciadv.adh8263. www.science.org/doi/10.1126/sciadv.adh8263

Targeting a coronavirus ion channel could yield new COVID-19 drugs

The genome of the SARS-CoV-2 virus encodes 29 proteins, one of which is an ion channel called E. This channel, which transports protons and calcium ions, induces infected cells to launch an inflammatory response that damages tissues and contributes to the symptoms of COVID-19.

MIT chemists have now discovered the structure of the "open" state of this channel, which allows ions to flow through. This structure, combined with the "closed" state structure that was reported by the same lab in 2020, could help scientists figure out what triggers the channel to open and close. These structures could also guide researchers in developing antiviral drugs that block the channel and help prevent inflammation.

When SARS-CoV-2 infects cells, the E channel embeds itself inside the membrane that surrounds a cellular organelle called the ER-Golgi intermediate compartment (ERGIC). The ERGIC interior has a high concentration of protons and calcium ions, which the E channel transports out of ERGIC and into the cell cytoplasm. That influx of protons and calcium leads to the formation of multiprotein complexes called inflammasomes, which induce inflammation.

Previous research has shown that when SARS-CoV-2 viruses are mutated so that they don't produce the E channel, the viruses generate much less inflammation and cause less damage to host cells.

So the E channel is an antiviral drug target now. If you can stop the channel from sending calcium into the cytoplasm, then you have a way to reduce the cytotoxic effects of the virus.

Joao Medeiros-Silva et al, Atomic Structure of the Open SARS-CoV-2 E Viroporin, Science Advances (2023). DOI: 10.1126/sciadv.adi9007. www.science.org/doi/10.1126/sciadv.adi9007

The three types of households with their typical characteristics and food waste behaviours. Credit: Trang Nguyen using Canva.com, CC BY-NC-ND

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 a fire retardant in building materials

Flu-resistant chickens
 Birds with small alterations to one gene are highly resistant to avian flu

Scientists have created the world’s first flu-resistant chickens in an advance that could pave the way for gene-edited poultry. The birds, which had small alterations to one gene, were highly resistant to avian flu, with nine in 10 birds showing no signs of infection when exposed to a typical dose of the virus.

However, infections were not completely blocked, and scientists say this would have to be achieved before genetically engineered chickens could be introduced to farms, due to the risk of the virus evolving to become more dangerous to humans.

https://www.nature.com/articles/s41467-023-41476-3

If you are not getting enough sleep, your vascular cells may be drowning in oxidants!

Several people in the world are in the same situation of sleep deprivation and habitually get only five to six hours of sleep instead of the recommended seven to eight hours.

But even a mild chronic sleep deficit may heighten the risk of developing heart disease later in life: Surveys of thousands of people have found that people who report mild but chronic sleep deficits have more heart disease later in life than people who get adequate sleep.

Published in Scientific Reports, a study of women now shows what's happening in the body during chronic mild sleep deprivation.

After just six weeks of shortened sleep, the study found, the cells that line our blood vessels are flooded by damaging oxidants. And unlike well-rested cells, sleep-restricted cells fail to activate antioxidant responses to clear the destructive molecules.

The result: cells that are inflamed and dysfunctional, an early step in the development of cardiovascular disease. This is some of the first direct evidence to show that mild chronic sleep deficits cause heart disease.

Riddhi Shah, Vikash Kumar Shah, Memet Emin, Su Gao, Rosemary V. Sampogna, Brooke Aggarwal, Audrey Chang, Marie-Pierre St-Onge, Vikas Malik, Jianlong Wang, Ying Wei, Sanja Jelic. Mild sleep restriction increases endothelial oxidative stress in female persons. Scientific Reports, 2023; 13 (1) DOI: 10.1038/s41598-023-42758-y

A theory on how gold, platinum, and other precious metals found their way into Earth's mantle

Scientists say they've hit the jackpot with some valuable new information about the story of gold.

It's a story that begins with violent collisions of large objects in space, continues in a half-melted region of Earth's mantle, and ends with precious metals finding an unlikely resting spot much closer to the planet's surface than scientists would have predicted.

Their new theory provides possible answers to lingering questions about the way gold, platinum, and other precious metals found their way to shallow pockets within Earth's mantle rather than deep in the planet's core. More broadly, the new theory offers insights into planet formation throughout the universe.

Recent research from scientists around the world has established that precious metals such as gold and platinum came to Earth billions of years ago after the early proto-Earth collided with large, moon-sized bodies in space, which left behind deposits of materials that were folded into what is today's Earth.

Aside from being valued for their scarcity, aesthetic beauty, and use in high-tech products, gold and platinum are what is known as highly "siderophile" elements. They are drawn to the element iron to such a degree that they would be expected to collect almost entirely in Earth's metallic core—either by merging directly with the metal core on impact or by sinking quickly from the mantle into the core.

By this logic, they should not have collected at or near the Earth's surface. Yet they did.

The new theory centers around a thin, "transient" region of the mantle, where the shallow part of the mantle melts and the deeper part remains solid. The researchers found that this region has peculiar dynamic properties that can efficiently trap falling metallic components and slowly deliver them to the rest of the mantle. 

Their theory posits that this delivery is still ongoing, with the remnants of the transient region appearing as "large low-shear-velocity provinces"—well-known geophysical anomalies in the deep mantle.

This transient region almost always forms when a big impactor hits the early Earth, making this new  theory quite robust.

 Jun Korenaga et al, Vestiges of impact-driven three-phase mixing in the chemistry and structure of Earth's mantle, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2309181120

Scientists identify nature's missing evolutionary law

A paper published in the Proceedings of the National Academy of Sciences describes "a missing law of nature," recognizing for the first time an important norm within the natural world's workings.

In essence, the new law states that complex natural systems evolve to states of greater patterning, diversity, and complexity. In other words, evolution is not limited to life on Earth, it also occurs in other massively complex systems, from planets and stars to atoms, minerals, and more.

"Macroscopic" laws of nature describe and explain phenomena experienced daily in the natural world. Natural laws related to forces and motion, gravity, electromagnetism, and energy, for example, were described more than 150 years ago.

The new work presents a modern addition—a macroscopic law recognizing evolution as a common feature of the natural world's complex systems, which are characterized as follows:

• They are formed from many different components, such as atoms, molecules, or cells, that can be arranged and rearranged repeatedly
• Are subject to natural processes that cause countless different arrangements to be formed
• Only a small fraction of all these configurations survive in a process called "selection for function."

Part 1

Regardless of whether the system is living or nonliving, when a novel configuration works well and function improves, evolution occurs.

The authors' "Law of Increasing Functional Information" states that the system will evolve "if many different configurations of the system undergo selection for one or more functions."

In the case of biology, Darwin equated function primarily with survival—the ability to live long enough to produce fertile offspring.

The new study expands that perspective, noting that at least three kinds of function occur in nature.

The most basic function is stability—stable arrangements of atoms or molecules are selected to continue. Also chosen to persist are dynamic systems with ongoing supplies of energy.

The third and most interesting function is "novelty"—the tendency of evolving systems to explore new configurations that sometimes lead to startling new behaviors or characteristics.

Part 2

Life's evolutionary history is rich with novelties—photosynthesis evolved when single cells learned to harness light energy, multicellular life  evolved when cells learned to cooperate, and species evolved thanks to advantageous new behaviors such as swimming, walking, flying, and thinking.

The same sort of evolution happens in the mineral kingdom. The earliest minerals represent particularly stable arrangements of atoms. Those primordial minerals provided foundations for the next generations of minerals, which participated in life's origins. The evolution of life and minerals are intertwined, as life uses minerals for shells, teeth, and bones.

Indeed, Earth's minerals, which began with about 20 at the dawn of our solar system, now number almost 6,000 known today thanks to ever more complex physical, chemical, and ultimately biological processes over 4.5 billion years.

In the case of stars, the paper notes that just two major elements—hydrogen and helium—formed the first stars shortly after the big bang. Those earliest stars used hydrogen and helium to make about 20 heavier chemical elements. And the next generation of stars built on that diversity to produce almost 100 more elements.

Part 3

The universe generates novel combinations of atoms, molecules, cells, etc. Those combinations that are stable and can go on to engender even more novelty will continue to evolve. This is what makes life the most striking example of evolution, but evolution is everywhere."

Among many implications, the paper offers:

1. Understanding into how differing systems possess varying degrees to which they can continue to evolve. "Potential complexity" or "future complexity" have been proposed as metrics of how much more complex an evolving system might become
2. Insights into how the rate of evolution of some systems can be influenced artificially. The notion of functional information suggests that the rate of evolution in a system might be increased in at least three ways: (1) by increasing the number and/or diversity of interacting agents, (2) by increasing the number of different configurations of the system; and/or (3) by enhancing the selective pressure on the system (for example, in chemical systems by more frequent cycles of heating/cooling or wetting/drying).
3. A deeper understanding of generative forces behind the creation and existence of complex phenomena in the universe, and the role of information in describing them
4. An understanding of life in the context of other complex evolving systems. Life shares certain conceptual equivalencies with other complex evolving systems, but the authors point to a future research direction, asking if there is something distinct about how life processes information on functionality (see also https://royalsocietypublishing.org/doi/10.1098/rsif.2022.0810).
5. Aiding the search for life elsewhere: if there is a demarcation between life and non-life that has to do with selection for function, can we identify the "rules of life" that allow us to discriminate that biotic dividing line in astrobiological investigations? (See also "Did Life Exist on Mars? Other Planets? With AI's Help, We May Know ...")
6. At a time when evolving AI systems are an increasing concern, a predictive law of information that characterizes how both natural and symbolic systems evolve is especially welcome

Laws of nature—motion, gravity, electromagnetism, thermodynamics—etc. codify the general behavior of various macroscopic natural systems across space and time.

The "law of increasing functional information" complements the 2nd law of thermodynamics, which states that the entropy (disorder) of an isolated system increases over time (and heat always flows from hotter to colder objects).

On the roles of function and selection in evolving systems, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2310223120. doi.org/10.1073/pnas.2310223120

Part 4

Why a spinning magnet can cause a second magnet to levitate

A team of physicists has found the reason a spinning magnet can cause a secondary magnet to levitate without the need for stabilization. In their paper published in the journal Physical Review Applied, the group describes experiments they conducted to learn more about the phenomenon and what they learned from them.

Prior research and anecdotal evidence have shown that if two magnets with north poles facing one another are brought close together, they will repel one another. Such force has been used for applications such as levitating trains. But these applications must account for the inherent instability that arises when magnets repel each other. More recently, scientists have found that if one of the magnets is spun at high speed, a second magnet can be repelled without the need for stabilizing—it remains levitated even when the first magnet is moved around. In this new effort, the researchers have uncovered the reason for such behavior. To learn more about the phenomenon, the research team paired several different types of magnets and spun them at different speeds while recording the action with high-speed cameras and motion tracking software. In studying the resulting imagery, the team was able to uncover the reason for the behavior.

Part 1

The researchers found that the secondary magnet (which they call a floater) rotated in sync with the rotor magnet—they spun at the same speed. They also found that the axis of the rotor magnet spun with a slight tilt—a situation that would destabilize the two magnets if they were not spinning. To better understand what was happening, the researchers created a simulation that allowed them to more easily manipulate the two magnets and their behavior.

They found that the magnetic field of the rotor magnet exerted some amount of torque on the floater resulting in the two magnets rotating in sync due to a gyroscopic effect. But the floater resisted, if only slightly, which accounted for the parallel configuration that developed. They also found that there was a very small amount of misalignment of the polar axis of the rotor magnet relative to its magnetic field—the resulting attractive and repulsive forces balanced each other out, allowing the floater to be held in a steady position during levitation.

Joachim Marco Hermansen et al, Magnetic levitation by rotation, Physical Review Applied (2023). DOI: 10.1103/PhysRevApplied.20.044036. On arXiv: doi.org/10.48550/arXiv.2305.00812

Digitally creating 16 million colours by chemistry

The DNA double helix is composed of two DNA molecules whose sequences are complementary to each other. The stability of the duplex can be fine-tuned in the lab by controlling the amount and location of imperfect complementary sequences.

Fluorescent markers bound to one of the matching DNA strands make the duplex visible, and fluorescence intensity increases with increasing duplex stability. Now, researchers  succeeded in creating fluorescent duplexes that can generate any of 16 million colours—a work that surpasses the previous 256 colours limitation.

This very large palette can be used to "paint" with DNA and to accurately reproduce any digital image on a miniature 2D surface with 24-bit color depth.

Tadija Kekić et al, A Canvas of Spatially Arranged DNA Strands that Can Produce 24-bit Color Depth, Journal of the American Chemical Society (2023). DOI: 10.1021/jacs.3c06500

Superlensing without a super lens: Physicists boost microscopes beyond limits

Ever since Antonie van Leeuwenhoek discovered the world of bacteria through a microscope in the late seventeenth century, humans have tried to look deeper into the world of the infinitesimally small.

There are, however, physical limits to how closely we can examine an object using traditional optical methods. This is known as the diffraction limit and is determined by the fact that light manifests as a wave. It means a focused image can never be smaller than half the wavelength of light used to observe an object.

Attempts to break this limit with "super lenses" have all hit the hurdles of extreme visual losses, making the lenses opaque. Now physicists  have shown a new pathway to achieve superlensing with minimal losses, breaking through the diffraction limit by a factor of nearly four times. The key to their success was to remove the super lens altogether.

The work should allow scientists to further improve super-resolution microscopy, the researchers say. It could advance imaging in fields as varied as cancer diagnostics, medical imaging, or archaeology and forensics.

Researchers have now developed a practical way to implement superlensing, without a super lens. To do this, they placed their light probe far away from the object and collected both high- and low-resolution information. By measuring further away, the probe doesn't interfere with the high-resolution data, a feature of previous methods.

Part 1

Previous attempts have tried to make super lenses using novel materials. However, most materials absorb too much light to make the super lens useful.

Now researchers overcame this by performing the superlens operation as a post-processing step on a computer, after the measurement itself. This produces a 'truthful' image of the object through the selective amplification of evanescent (or vanishing) light waves.

This method could be applied to determine moisture content in leaves with greater resolution, or be useful in advanced microfabrication techniques, such as non-destructive assessment of microchip integrity. And the method could even be used to reveal hidden layers in artwork, perhaps proving useful in uncovering art forgery or hidden works.

 Subwavelength terahertz imaging via virtual superlensing in the radiating near field, Nature Communications (2023). DOI: 10.1038/s41467-023-41949-5

Researchers discover one of the world's darkest rivers

When the researchers came upon the Ruki River, they were quite taken aback. The water in this river, a tributary of the mighty Congo River, is so dark that you literally can't see your hand in front of your face.

Comparisons with other major tropical rivers show that the Ruki may even be the blackest large blackwater river on Earth—it's certainly a lot darker than the famous Rio Negro in the Amazon. The reason the water is black is that it contains large amounts of dissolved organic material and hardly any sediment because of the river's low gradient. These carbon-rich substances are mostly washed into the river by the rain, which falls on dead jungle vegetation and leaches out organic compounds from the decomposing plant material. What's more, the river floods the forest in the rainy season. It can take weeks for the often waist-deep water to slowly retreat, during which time it leaches organic substances.

The Ruki is one of the most DOC-rich river systems in the world (dissolved organic carbon). DOC usually comes in the form of organic acids that increase the acidity of the river water. This stimulates the release of carbon dioxide (CO₂) as the acids dissolve carbonates present in the water.

Travis W. Drake et al, Hydrology drives export and composition of carbon in a pristine tropical river, Limnology and Oceanography (2023). DOI: 10.1002/lno.12436

Simulating cold sensation without actual cooling

Our skin plays a key role in perceiving temperature and the surroundings. For instance, we perceive the chill of the outdoors when our cheeks blush with cold, and we sense the onset of spring when our skin warms up gradually.

However, getting exposed to the same stimuli repeatedly, makes us accustomed to the stimuli, making it challenging to sense new sensations. This process, known as "temperature acclimatization," can interfere with our ability to gauge temperature changes in a virtual reality (VR) environment while switching scenes.

In a new study, researchers have developed a non-contact technology for simulating a cold sensation that continually generates thermal experiences while maintaining nearly constant skin temperature. This innovative approach leverages human body's natural sensitivity to rapid temperature changes.

The technology employs a combination of cold air flow and a light source to instantly switch between a quick cold and a gentle warm stimulus, inducing a cold sensation while maintaining the skin temperature fluctuations close to zero. Evaluation results have demonstrated that this system can provide a virtual cold sensation without any actual change in temperature. Moreover, the researchers have succeeded in replicating a cold sensation of the same intensity as one would experience with continuous skin temperature changes.

This technology offers a novel perspective on simulating skin sensations without altering the body's physical state. 

Jiayi Xu et al, Integration of Independent Heat Transfer Mechanisms for Non-Contact Cold Sensation Presentation With Low Residual Heat, IEEE Transactions on Haptics (2023). DOI: 10.1109/TOH.2023.3324754

Scientists develop innovative magnetic gel that heals diabetic wounds three times faster

Diabetic patients whose natural wound-healing capabilities are compromised often develop chronic wounds that are slow to heal. Such non-healing wounds could cause serious infections resulting in painful outcomes, such as limb amputation. To address this global health care challenge, a team of researchers  engineered an innovative magnetic gel that promises to accelerate the healing of diabetic wounds, reduce the rates of recurrence, and in turn, lower the incidents of limb amputations.

Each treatment involves the application of a bandage pre-loaded with a hydrogel containing skin cells for healing and magnetic particles. To maximize therapeutic results, a wireless external magnetic device is used to activate skin cells and accelerate the wound healing process. The ideal duration of magnetic stimulation is about one to two hours.

Lab tests showed the treatment coupled with magnetic stimulation healed diabetic wounds about three times faster than current conventional approaches. Furthermore, while the research has focused on healing diabetic foot ulcers, the technology has potential for treating a wide range of complex wounds such as burns.

Yufeng Shou et al, Mechano‐activated Cell Therapy for Accelerated Diabetic Wound Healing, Advanced Materials (2023). DOI: 10.1002/adma.202304638

Robots helped understand how insects evolved two distinct strategies of flight

Mystery of Dead Whales Washing Up on US Coast May Be Solved

Gray whales have been washing up dead on the Pacific coast at an alarming rate since 2019, and scientists think they might finally know why.

The gray whale strandings from Mexico all the way to Alaska have been declared an "unusual mortality event," or a significant die-off of a species that is unexplained and requires a quick response.

Two other mass die-offs of gray whales occurred in the 1980s and 1990s, though those only lasted a couple of years; the latest is still ongoing. The latest die-off has caused the North Pacific gray whale population to plummet from an estimated 27,000 in 2016 to 14,500 in 2023, according to the National Oceanic and Atmospheric Administration. For years, researchers could only guess what was killing the whales. NOAA has previously noted that emaciation had been observed in some of the dead whales, but not in others. But scientists at Oregon State University's Marine Mammal Institute now say there is strong evidence that the whale deaths are linked directly to sea ice melting in the Arctic, according to a study published recently in the journal Science.

The decrease in sea ice was also causing the gray whales' food supply to diminish.

Part 1

Gray whales make the longest migration of any mammal on Earth, traveling more than 12,000 miles every year from their foraging grounds in the Arctic, where they spend the summers, to their breeding grounds in the warm, shallow lagoons of Mexico's Baja Peninsula, where they spend the winters.

While in the Arctic, the gray whales feed on amphipod crustaceans. Amphipods in turn feed on algae, which grows on the underside of sea ice.

With less ice, you get less algae, which is worse for the gray whale prey. When there are sudden declines in the quality of prey, the population of gray whales is significantly affected.

In other words, the melting sea ice disrupts the entire food chain.

The decrease in available food can cause skinnier or malnourished whales, as well as lower birth rates.

Even highly mobile, long-lived species such as gray whales are sensitive to climate change impacts.

Part 2

**

https://www.businessinsider.in/science/news/gray-whales-have-been-m...

Scientists Show Structural, Brain-Wide Changes During Menstruation

The constant ebb and flow of hormones that guide the menstrual cycle don't just affect reproductive anatomy. They also reshape the brain, and a new study has given us insight into how this happens.

A team of researchers tracked 30 women who menstruate over their cycles, documenting in detail the structural changes that take place in the brain as hormonal profiles fluctuate.

These results are the first to report simultaneous brain-wide changes in human white matter microstructure and cortical thickness coinciding with menstrual cycle-driven hormone rhythms," the researchers write.

Strong brain-hormone interaction effects may not be limited to classically known hypothalamic-pituitary-gonadal-axis (HPG-axis) receptor-dense regions.

Cyclic fluctuations in HPG-axis hormones exert powerful behavioural, structural, and functional effects through actions on the mammalian central nervous system.

The microstructure of white matter – the fatty network of neuronal fibers that transfer information between regions of gray matter – has been found to change with hormonal shifts, including puberty, oral contraception use, gender-affirming hormone therapy, and post-menopausal estrogen therapy.

To address the menstruation gap in our understanding, the team took MRI scans of their subjects during three menstrual phases: menses, ovulation, and mid-luteal. At the time of each of these scans, the researchers also measured the participants' hormone levels.

In particular, just before ovulation, when the hormones 17β-estradiol and luteinizing hormone rise, the brains of the participants showed white matter changes suggesting faster information transfer.

Follicle-stimulating hormone, which rises before ovulation, and helps stimulate the ovary follicles, was associated with thicker gray matter.

Progesterone, which rises after ovulation, was associated with increased tissue and decreased cerebrospinal fluid volume.

What this means for the person driving the brain is unknown, but the research lays the groundwork for future studies, and perhaps understanding the causes of unusual but severe period-related mental health problems.

These findings may have implications for hormone-driven alterations in behavior and cognition," the researchers write.

https://www.biorxiv.org/content/10.1101/2023.10.09.561616v1

Part 2

Evidence of Earth's core leaking found 

A  team of geochemists has found evidence of high levels of helium-3 in rocks on Baffin Island—possible evidence that the Earth's core is leaking. 

Prior researchers found trace elements of helium-3 in lava flows on Baffin Island, hinting at the possibility that the Earth's core might be leaking. This is because it is an ancient isotope—it was prevalent during the time when Earth was forming and became trapped in the core. But because of its nature, helium-3 that makes its way to the surface soon escapes into the atmosphere and disappears into space. Thus, helium-3 is rare. If it is found on the surface, the odds are high that it made its way out of the core.

Intrigued by the possibility that the Earth's core might be leaking, the research team ventured to Baffin Island and began testing multiple lava flows. They found much higher levels of helium-3 than observed in prior research efforts—higher than anywhere else on Earth. They also found high ratios of helium-3 to helium-4 (a common isotope)—the highest that have ever been measured in terrestrial rock. Such high ratios, the researchers suggest, is another factor suggesting that the helium-3 is leaking from the core.

The research team notes that finding such high levels of helium-3 at a terrestrial site is a big deal, because if it can be proved that the material is indeed leaking from the core, it will provide scientists with a way to study core material, which has never been done before. That could reveal more about the core than previously thought possible. They note that if the helium-3 is coming from the core, then the other material around it should be as well, offering further physical examples of core material.

F. Horton et al, Highest terrestrial 3He/4He credibly from the core, Nature (2023). DOI: 10.1038/s41586-023-06590-8

10 billion snow crabs starved to death in the Bering Sea because ...

A team of marine biologists has solved the mystery of why approximately 10 billion snow crabs vanished from the Bering Sea back in 2018/2019—the water there was too warm for them!

In their study, reported in the journal Science, the group used data from previous studies on the way snow crabs respond to warmer temperatures to solve the mystery.

Snow crabs are relatively small crabs, that, despite their name, are not white—they are red, like lobsters. They live on the ocean floor in shallow areas and have been consumed as a seafood delicacy for many years.

Alaskan fishermen (and scientists) first noticed a dramatic decline in their numbers back in 2021. Then, due to the pandemic, fishing and studying of the crabs was put on hiatus for a year. The full extent of the crab disappearance was only observed earlier in 2023—over 10 billion were missing. Upon discovering this alarming decline, a research team set to work to figure out what happened.

The team started by scouting nearby areas, hoping that the crabs had simply moved to another location, but no sign of them could be found. Next, noting that the area had experienced a heat wave prior to, and during, the crab disappearance they turned to the results of a prior study that had found that when water temperatures increase, energy requirements for the crabs increase. The researchers found that if water temperatures increased by just 3°C, the caloric needs of the crabs doubled.

Records showed that during the heat wave, water temperatures had risen 3°C, which meant the crabs would have needed twice as much food to sustain themselves. The research team also found that just prior to the heat wave, the crab population had risen dramatically, meaning that there had been a large increase in competition for food. And that, the researchers conclude, led the crabs to starve to death.

Need we give more evidence to  what might happen to the heat sensitive creatures during  global warming?

Cody S. Szuwalski et al, The collapse of eastern Bering Sea snow crab, Science (2023). DOI: 10.1126/science.adf6035

Gordon H. Kruse, Are crabs in hot water?, Science (2023). DOI: 10.1126/science.adk7565

New study shows Hunga-Tonga Hunga-Ha'apai eruption depleted ozone layer

A large team of atmospheric specialists has found that when the Hunga-Tonga Hunga-Ha'apai volcano erupted last year, it took part of the ozone layer with it. Their findings are published in the journal Science.

Prior research has shown that the Hunga-Tonga Hunga-Ha'apai eruption was one of the more powerful explosions ever recorded. It was also unique in that instead of spewing just volcanic material, dirt and rocks, it also sent a very large amount of ocean water into the atmosphere. In this new effort, the research team have found that all that saltwater reacting with other chemicals in the atmosphere, resulted in breaking down O₃ in the ozone layer.

To learn more about the impact of the eruption, the researchers sent balloons with sensors into the atmosphere from nearby Réunion Island just five days after the volcano erupted. In studying the data from the sensors, the researchers found that ozone levels in the plume were approximately 30% below normal levels.

As the balloons continued to monitor the plume as it floated across the Indian and then Pacific Ocean, they found depletion totals of approximately 5%. The depletion, they found was due to ocean water reacting with molecules in the atmosphere that contained chlorine, leading to a breakdown of ozone—in amounts that had never been seen before in such a short time.

 Stephanie Evan et al, Rapid ozone depletion after humidification of the stratosphere by the Hunga Tonga Eruption, Science (2023). DOI: 10.1126/science.adg2551

Deep dive into the gut unlocks new disease treatments

The more diverse species in your gut, the better it is for your health. Now an international team has found a way to determine which species are important and how they interact to create a healthy microbiome.

Understanding these relationships opens the door to a new world of medical opportunities for conditions from inflammatory bowel disease to infections, autoimmune diseases and cancers.

There are roughly 1,000 different bacterial species in a healthy gut—it's a microscopic multicultural community with over a trillion individual members.

Bacteria in our microbiomes exist as communities that rely on each other to produce and share key nutrients between them.

Researchers have developed a new computational way to understand these dependencies and their role in shaping human microbiome. This new method unlocks our understanding of the gut microbiome and provides a foundation for new treatment options that selectively remodel microbial communities.

For example, in Crohn's Disease, the team confirmed the importance of hydrogen sulfide. They discovered that the most likely cause is loss of bacteria that use hydrogen sulfide, not an increase in species producing it, as was previously thought. 

This is a significant step in the development of complex microbial therapies. This approach allows us to identify and rank the key interactions between bacteria and use this knowledge to predict targeted ways to change the community.

Part 1

Microbiome facts
There are trillions of microbes living inside and on the surface of your body; together they are called the microbiome and they are vital to your health and fighting disease.
Since the microbiome was first recognized in the late 1990s, scientists have identified more than 2,000 microbial species from the largest microbiome, in the gut.
The skin, bladder and genitals also harbor microbiome populations.
Your gut microbiome composition is unique to you and effects your metabolism, gastrointestinal tract, brain, and immune system.
In a healthy person, the symbiotic and pathogenic microbes work in balance.
Imbalances between symbiotic (benefiting you and the microbes) and pathogenic (disease-causing) microbes, known as dysbiosis, disrupt the microbes, making people more susceptible to conditions such as inflammatory bowel disease (IBD) and Clostridioides difficile infection, which causes severe diarrhea and inflammation of the colon or colitis.
There is hope that we may soon be on the cusp of a new era of health care that nurtures and tweaks the microbiome to optimize human health.

Disease-specific loss of microbial cross-feeding interactions in the human gut, Nature Communications (2023). DOI: 10.1038/s41467-023-42112-w

Part 2

Why do some men not produce sperm? Scientists uncover one underlying reason for male infertility

Millions of couples worldwide experience infertility with half of the cases originating in men. For 10% of infertile males, little or no sperm are produced. Now, new research is shedding light on what may be going wrong in the process of sperm formation, leading to potential theories on possible treatments.

In most sexually-reproducing species, including humans, a critical protein structure resembling a lattice-like bridge needs to be built properly to produce sperm and egg cells. The team  discovered that in mice, changing a single and very specific point in this bridge caused it to collapse, leading to infertility and thus providing insight into human infertility in males due to similar problems with meiosis.

Part 1

Meiosis, the cell division process giving rise to sperm and eggs, involves several steps, one of which is the formation of a large protein structure called the synaptonemal complex. Like a bridge, the complex holds chromosome pairs in place enabling necessary genetic exchanges to occur that are essential for the chromosomes to then correctly separate into sperm and eggs.

A significant contributor to infertility is defects in meiosis.  what happens right before that when the synaptonemal complex forms between the daughter reproductive cells .

Previous studies have examined many proteins comprising the synaptonemal complex, how they interact with each other, and have identified various mutations linked to male infertility. The protein the researchers investigated in this study forms the lattices of the proverbial bridge, which has a section found in humans, mice, and most other vertebrates suggesting it is critical for assembly. Modeling different mutations in a potentially crucial region in the human protein enabled the team to predict which of these might disrupt protein function.

The authors used a precise gene editing technique to make mutations in one key synaptonemal complex protein in mice, which allowed the researchers, for the first time, to test the function of key regions of the protein in live animals. Just a single mutation, predicted from the modeling experiments, was verified as the culprit of infertility in mice.

Katherine Billmyre et al, SYCP1 head-to-head assembly is required for chromosome synapsis in mouse meiosis, Science Advances (2023). DOI: 10.1126/sciadv.adi1562. www.science.org/doi/10.1126/sciadv.adi1562

Part 2

Maternal microbiota can affect fetal development

In a new study, significant differences in the gene activity of the faetal intestine, brain and placenta were identified, depending on the microbes in the mother's body and the compounds produced by them. The findings indicate that maternal microbes are important to her offspring's development and health.

The microbiota of the mother, or dam, is thought to be important for the development and health of her offspring. However, so far little is known about how interactions with the microbiota begin and what the mechanisms of action are.

A collaborative study investigated how the maternal microbiota affects fetal development by comparing the fetuses of normal and germ-free mouse dams living in a sterile environment. The researchers measured gene expression and the concentrations of small-molecular compounds, or metabolites, in the fetal intestine, brain and placenta.

This new  study sheds light on the significance of the microbiota and the mechanisms by which the microbiota affects individual development and pregnancy. Researchers identified previously unknown compounds in the fetus, which are likely to be microbial, and which can be important for individual development.

Part 1

The researchers demonstrated that there were considerable differences in gene expression in the intestine, brain and placenta of the fetuses of germ-free and normal mouse dams.

In the gut, genes associated with the immune system and host–microbe interactions were less active in the fetuses of germ-free dams. There were significant differences in the expression of genes in the brain associated with the development and functioning of the nervous system. In the placenta, there were differences in the expression of several important genes that regulate pregnancy.

The differences were more extensive in male fetuses, indicating that they may be more sensitive to the effects of the maternal microbiota, at least in mice.

The researchers discovered that the expression of many important genes was associated with the concentration of metabolites likely to be modulated by the maternal microbiota. These metabolites were absent in the fetuses of germ-free dams, or occurred at least at significantly lower concentrations.

Aleksi Husso et al, Impacts of maternal microbiota and microbial metabolites on fetal intestine, brain, and placenta, BMC Biology (2023). DOI: 10.1186/s12915-023-01709-9

Part 2

The encounter between Neanderthals and Homo sapiens as told by their genomes

 About 40,000 years ago, Neanderthals, who had lived for hundreds of thousands of years in the western part of the Eurasian continent, gave way to Homo sapiens, who had arrived from Africa. This replacement was not sudden, and the two species coexisted for a few millennia, resulting in the integration of Neanderthal DNA into the genome of Homo sapiens.

Researchers  have analyzed the distribution of the portion of DNA inherited from Neanderthals in the genomes of humans (Homo sapiens) over the last 40,000 years. These statistical analyses revealed subtle variations in time and geographical space. This work, published in the journal Science Advances, helps us to understand the common history of these two species.

Thanks to genome sequencing and comparative analysis, it is established that Neanderthals and Homo sapiens interbred and that these encounters were sometimes fruitful, leading to the presence of about 2% of DNA of Neanderthal origin in present-day Eurasians. However, this percentage varies slightly between regions of Eurasia, since DNA from Neanderthals is somewhat more abundant in the genomes of Asian populations than in those of European populations.

One hypothesis to explain this difference is that natural selection would not have had the same effect on genes of Neanderthal origin in Asian and European populations.

Another new theory suggests that such differences could be explained by migratory flows: when a migrant population hybridizes with a local population, in their area of cohabitation, the proportion of DNA of the local population tends to increase with distance from the point of departure of the migrant population.

In the case of Homo sapiens and Neanderthals, the hypothesis is that the further one moves away from Africa, Homo sapiens' point of origin, the greater the proportion of DNA from Neanderthal, a population mainly located in Europe. To test this hypothesis, the authors used a database made available by Harvard Medical School that includes more than 4,000 genomes from individuals who have lived in Eurasia over the past 40 millennia.

Statistical analyses revealed that, in the period following the dispersal of Homo sapiens from Africa, the genomes of Paleolithic hunter-gatherers who lived in Europe contained a slightly higher proportion of DNA of Neanderthal origin than the genomes of those who lived in Asia. This result is contrary to the current situation but in agreement with paleontological data, since the presence of Neanderthals was mainly reported in western Eurasia (no Neanderthal bones have been discovered further east than the Altai region of Siberia).

Subsequently, during the transition to the Neolithic, i.e. the transition from the hunter-gatherer lifestyle to the farmer lifestyle, 10,000 to 5,000 years ago, the study shows a decline in the proportion of DNA of Neanderthal origin in the genomes of European populations, resulting in a slightly lower percentage than that of Asian populations (as currently observed).

This study shows that the analysis of ancient genomes, coupled with archaeological data, makes it possible to trace different stages in the history of hybridized species.

Claudio S. Quilodrán, Jérémy Rio, Alexandros Tsoupas, Mathias Currat. Past human expansions shaped the spatial pattern of Neanderthal ancestry. Science Advances, 2023; 9 (42) DOI: 10.1126/sciadv.adg9817

Two probiotics identified as promising hypertension treatments

An estimated 40% of the global adult population have high blood pressure, or hypertension, which puts people at risk of cardiovascular disease and other dangerous health conditions. Recent studies suggest that probiotics may offer a protective effect, but researchers have a limited understanding of why shaping the gut microbiota can regulate blood pressure.

A study published in mSystems adds two new strains to the list of potential antihypertensive probiotics.

In experiments on hypertensive mice, treatment with the two probiotics, Bifidobacterium lactis and Lactobacillus rhamnosus, returned blood pressure to normal levels. The researchers also tracked how those probiotics altered the animals' gut microbial mix over 16 weeks, identifying specific microbes and metabolic pathways that may help explain the protective effect.

Accumulated evidence supports an antihypertensive effect of probiotics and probiotic fermented foods in both in vitro and in vivo experiments

Previous studies have connected the rising rates of hypertension worldwide to increasing consumption of sugar. It likely boosts blood pressure through many mechanisms—increased insulin resistance or salt retention, for example—but in recent years researchers have investigated sugar's effect on the gut microbiome, as well.

In the new study, the researchers tested the two probiotic strains on mice that developed high blood pressure after consuming water mixed with fructose. Over 16 weeks, they measured the animals' blood pressures every four weeks. They found that fructose-fed mice that received either probiotic showed significantly lower blood pressures than those fed a high fructose diet and not treated with probiotics.

The researchers used shotgun metagenomic sequencing to probe connections between the altered gut microbiota and the change in blood pressure. They found that a high-fructose diet in the mice led to an increase in Bacteroidetes and a decrease in Firmicutes bacteria; however, treatment with probiotics returned those populations to those found in the control group. In addition, the analysis identified new microbial signatures associated with blood pressure: Increased levels of Lawsonia and Pyrolobus bacteria, and reduced levels of Alistipes and Alloprevotella, were associated with lower blood pressure.

 mSystems (2023). journals.asm.org/doi/10.1128/msystems.00331-23