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Comment by Dr. Krishna Kumari Challa on February 4, 2025 at 9:18am

Many animals and plants are losing their genetic diversity, making them more vulnerable

Two-thirds of animal and plant populations are declining in genetic diversity, which makes it harder to adapt to environmental changes, according to research published this week.

Long before a species goes extinct, the population becomes smaller and more fragmented, shrinking the number of potential mates and therefore genetic mixing. This leaves a species more vulnerable to future threats such as disease.

A surprising trend was that we saw genetic diversity declining even among many species that aren't considered at risk. 

Researchers examined data for 628 species studied between 1985 and 2019. The greatest losses in genetic variation were seen in birds and mammals.

Findings were published in the journal Nature.

When a species has different genetic solutions, it's better able to deal with changes. 

If a new disease spreads through a population or climate change alters summer rainfall, some individuals will fare better than others, in part because of their genes. Higher genetic diversity also means there's a greater chance of a species' survival.

Conservation efforts to connect isolated populations—basically expanding the dating pool for a particular species—can help maintain or even restore genetic diversity.

Isolated populations suffer. The solution is to reconnect them, stress the biologists.

Catherine Grueber, Global meta-analysis shows action is needed to halt genetic diversity loss, Nature (2025). DOI: 10.1038/s41586-024-08458-x. www.nature.com/articles/s41586-024-08458-x

Comment by Dr. Krishna Kumari Challa on February 4, 2025 at 9:11am

Octopuses have some of the oldest known sex chromosomes, study finds

The octopus just revealed another one of its secrets: what determines its sex.

Researchers have identified a sex chromosome in the California two-spot octopus. This chromosome has likely been around for 480 million years, since before octopuses split apart from the nautilus on the evolutionary tree. That makes it one of the oldest known animal sex chromosomes.

The finding also is evidence that octopuses and other cephalopods, a class of sea animals that includes squid and nautiluses, do use chromosomes to determine their sex, answering a longstanding mystery.

The researchers  described the findings Feb. 3 in the journal Current Biology.

In humans and most mammals, sex is determined largely by chromosomes. But "there's a tremendous amount of diversity" in how animals determine their sex.

In turtles, for instance, sex is determined by the temperature at which the eggs are incubated. Some fish have a gene that determines sex, but not a whole chromosome. Even in humans, the X/Y sex chromosome system isn't as clear-cut as it might look on paper; gene mutations or inheriting extra sex chromosomes can lead to development that doesn't neatly fit in a male/female binary.

When  researchers recently sequenced the DNA of a female California two-spot octopus, they found something unexpected: a chromosome with only half the amount of genetic material. It looked different from all the others, and it hadn't been found in male octopuses whose DNA was previously sequenced.

This particular chromosome had half the amount of sequencing data, which indicated there was only one copy.

To confirm, the researchers sorted through other octopus genomic data previously collected by other researchers.

They found another example of the half-sized chromosome in another species of octopus. They also found it in squid, which diverged evolutionarily from octopuses somewhere between 248 and 455 million years ago. And after more digging, they also found evidence for the chromosome in the nautilus, a mollusk that split apart from the octopus approximately 480 million years ago.

The fact that these species share this unique chromosome suggests that it's been around in some form for a very long time.

This indicates that their common ancestor had this similar sex determination system.

That's somewhat unusual for sex chromosomes. Because they directly impact reproductive capabilities, they're subject to a lot of selective pressure and so tend to undergo rapid evolutionary change. But cephalopods seem to have found what works and have stuck with it.

Other ancient sex chromosomes have been discovered in plant groups like mosses and liverworts, which were some of the first plants to evolve. And insect sex chromosomes might be 450 million years old, but they've also changed a lot over time.

Cephalopod Sex Determination and its Ancient Evolutionary Origin, Current Biology (2025). DOI: 10.1016/j.cub.2025.01.005. www.cell.com/current-biology/f … 0960-9822(25)00005-3

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 1:49pm

Catching the culprits: DNA 'fingerprints' of drug-makers can be linked to capsules and packaging

DNA profiling technologies are rapidly advancing, creating the potential to identify individuals involved in making, packing and transporting illegal capsules by analyzing the exterior of the illicit drugs and the plastic bag in which they are carried.

Experiments carried out by Flinders University forensic science experts have found that DNA accumulates in different areas, depending on an individual's involvement in the process, which could aid identification of people involved in the drug-making and trade.

The work is published in the journal Forensic Science International: Genetics.

The study also found DNA from the surface of capsules can be transferred to the inner surface of ziplock bags (ZLBs) commonly used in transportation.

This small-scale study indicates that capsule packers deposit less DNA than capsule makers who spend more time handling drug casing, and those that make the capsules can leave enough DNA for a complete profile with as little as 30 seconds of contact.

Furthermore, the DNA yield on these commonly used plastic bags is higher when handled by several people compared with little-to-no contact.

"Generating informative DNA profiles from the inside surface of the ziplock bag could be more useful than the outer side, as could be testing of other 'protected' areas of the bag such as the zip or inner edge of the seal.

Illicit substances frequently distributed in secure ziplock bags can be seized by police and tested by forensic investigators.

Strong DNA profiles 're generated for the individual who made the capsules and for the individual responsible for packing the ziplock bag.

Madison Nolan et al, Illicit drug distribution: Evaluation of DNA transfer between ziplock bags and capsules, Forensic Science International: Genetics (2024). DOI: 10.1016/j.fsigen.2024.103182

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 1:37pm

Scientists create 'molecular trap' to remove pollutants from water

Scientists have developed a new material that could help reduce water pollution caused by harmful chemicals, such as from leftover medicines and hygiene products, that end up in rivers and lakes.

Water pollution is one of the growing challenges of modern life. Many everyday items, from medications to cosmetics, leave behind residues that don't fully break down after use. These pollutants often find their way into water systems, where they disrupt ecosystems and cause harm to plants, animals and humans.

The research, published in the journal Cell Reports Physical Science, describes a new method using a molecular  structure called a metal-organic cage (MOC). These tiny cages act like traps designed to catch and hold harmful molecules commonly found in our water supplies.

The cages are made up of metal ions  connected by organic molecules forming a hollow pyramid-like structure. These hollow spaces at the center of these structures are where the MOCs trap specific molecules, like pollutants or gases.

The new structure incorporates chemical groups called sulfonates to make it compatible with water, allowing it to function in real-world water systems, like rivers or wastewater.

It uses a natural effect called hydrophobic binding, where contaminant molecules preferentially "stick" to the inside of the cage rather than staying in the water. This allows the material to selectively capture and hold pollutants, even in challenging water environments.

Jack D. Wright et al, Encapsulation of Hydrophobic Pollutants within a Large Water-Soluble [Fe₄L₆]^4- Cage, Cell Reports Physical Science (2025). DOI: 10.1016/j.xcrp.2025.102404

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 12:01pm

Why the first stars couldn't grow forever

Star formation in the early universe was a vigorous process that created gigantic stars. Called Population III stars, these giants were massive, extremely luminous stars that lived short lives, many of which ended when they exploded as primordial supernovae.

But even these early stars faced growth limitations.

Stellar feedback plays a role in modern star formation. As young stars grow, they emit powerful radiation that can disperse nearby gas they need to keep growing. This is called protostellar radiative feedback, and it takes place in addition to the restrictive effect their magnetic fields have on their growth.

However, new research shows that the growth of Pop III stars was limited by their magnetic fields.

The research is titled "Magnetic fields limit the mass of Population III stars even before the onset of protostellar radiation feedback"

The paper is published on the arXiv preprint server.

Piyush Sharda et al, Magnetic fields limit the mass of Population III stars even before the onset of protostellar radiation feedback, arXiv (2025). DOI: 10.48550/arxiv.2501.12734

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 11:58am

Microplastics found in the brains of mice within hours of consumption

A team of environmental biologists  has found that it takes microplastics consumed by mice just a few hours to make their way to their brains.

In their paper published in the journal Science Advances, the group describes experiments they conducted with lab mice consuming water tainted with different sized microplastics, and what they learned by doing so.

Prior research has shown that microplastics have made their way into the environment to such an extent that they have made their way into the bodies of nearly everyone on Earth (*). It is still not known what harm consumption of such materials causes, but most in the medical field believe they are likely causing damage that is blamed on other sources. Still, many in the field suggest that there is enough evidence of possible health problems associated with microplastics that action should be taken globally to address their impact.

In this new effort, the research team sought to learn more about the medical impact of a mammal consuming different sizes of microplastics. The experiments consisted of feeding test mice water with different sized bits of fluorescent plastic in it, from micro to nano. They then tracked the progress of the plastic bits to see where they wound up in the bodies of the mice.

Knowing that the plastic would make its way from the digestive tract into the bloodstream, the researchers used two-photon microscopy to capture imagery of it inside blood vessels. Also, suspecting that the tiniest bits would make it into their brains, the team installed tiny windows in their skulls, allowing them to track the movement of the plastic in their brains.

In studying the imagery they created, the researchers were able to watch as the plastics made their way around the mice's bodies, eventually reaching their brains. They also noted that the plastic bits tended to get backed up, like cars in a traffic jam at different points. In taking a closer look at some of the backups in the brain, the researchers found that the plastic bits had been captured by immune cells, which led to even more backups.

Wondering if the plastic in their brains was causing any impairment, the researchers tested several of the mice and found that many of them experienced memory loss, reductions in motor skills and lower endurance.

*  Richard C. Thompson, Twenty years of microplastics pollution research—what have we learned?, Science (2024). DOI: 10.1126/science.adl2746. www.science.org/doi/10.1126/science.adl2746

Haipeng Huang et al, Microplastics in the bloodstream can induce cerebral thrombosis by causing cell obstruction and lead to neurobehavioral abnormalities, Science Advances (2025). DOI: 10.1126/sciadv.adr8243

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 11:50am

Ocean-surface warming has more than quadrupled since the late-1980s, research shows

The rate of ocean warming has more than quadrupled over the past four decades, a new study has shown. Ocean temperatures were rising at about 0.06 degrees Celsius per decade in the late 1980s, but are now increasing at 0.27 degrees Celsius per decade.

Published 28 January 2025 in Environmental Research Letters, the study helps explain why 2023 and early 2024 saw unprecedented ocean temperatures.

This accelerating ocean warming is driven by the Earth's growing energy imbalance—whereby more energy from the sun is being absorbed in the Earth's system than is escaping back to space. This imbalance has roughly doubled since 2010, in part due to increasing greenhouse gas concentrations, and because the Earth is now reflecting less sunlight to space than before.

Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024. Some of this warmth came from El Niño, a natural warming event in the Pacific.

When scientists compared it to a similar El Niño in 2015–16, they found that the rest of the record warmth is explained by the sea surface warming up faster in the past 10 years than in earlier decades; 44% of the record warmth was attributable to the oceans absorbing heat at an accelerating rate.

Quantifying the acceleration of multidecadal global sea surface warming driven by Earth's energy imbalance, Environmental Research Letters (2025). DOI: 10.1088/1748-9326/adaa8a

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 11:40am

Importantly, this effect becomes more pronounced in heavier nuclei that contain more nucleons. In the heaviest element examined—carbon-12, which has 12 nucleons—the three-nucleon force caused the energy gap to widen by a factor of 2.5.

This effect is so large that it has almost equal weighting to the impact of the two-nucleon force.
The three-nucleon force could play a key role in understanding how heavy elements form from the fusion of lighter elements in stars. As this force grows stronger in heavier nuclei, it increases their stability by creating larger energy gaps between nuclear shells.

This stability makes it more challenging for the nucleus to capture additional neutrons, which are essential for forming heavier elements. In cases where the nucleus already contains a "magic number" of protons or neutrons that completely fills its shells, the nucleus becomes exceptionally stable, which can further hinder the fusion process.
Finally, the researchers discovered another surprising effect of the three-nucleon force on nucleon spins. With only the two-nucleon force, the spin states of both nucleons can be measured individually. However, the three-nucleon force creates quantum entanglement, where two of the three nucleons have spins that exist in both states at once until measured.

Tokuro Fukui et al, Uncovering the mechanism of chiral three-nucleon force in driving spin-orbit splitting, Physics Letters B (2024). DOI: 10.1016/j.physletb.2024.138839

Part 2

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 11:38am

An overlooked nuclear force helps keep matter stable, study reveals

Researchers have revealed how a special type of force within an atom's nucleus, known as the three-nucleon force, impacts nuclear stability. The study, published in Physics Letters B, provides insight into why certain nuclei are more stable than others and may help explain astrophysical processes, such as the formation of heavy elements within stars.

All matter is made of atoms, the building blocks of the universe. Most of an atom's mass is packed into its tiny nucleus, which contains protons and neutrons (known collectively as nucleons). Understanding how these nucleons interact to keep the nucleus stable and in a low energy state has been a central question in nuclear physics for over a century.

The most powerful nuclear force is the two-nucleon force, which attracts two nucleons at long range to pull them together and repels at short range to stop the nucleons from getting too close.

Scientists have formed a good understanding of the two-nucleon force and how it impacts nuclear stability. On the other hand, three-nucleon force, which is when three nucleons interact with each other simultaneously, is much more complicated and poorly understood.

The researchers describe nuclear forces by likening them to a game of catch. With the two-nucleon force, two players, or nucleons, interact by throwing a ball to each other. The ball, a subatomic particle called a meson, can vary in heaviness, with the lightest meson, known as a pion, responsible for the long-range attraction between nucleons.

With the three-nucleon force, there are three players, or nucleons, and balls, or mesons, are passed between them. At the same time as throwing and catching the balls, the players, or nucleons, also spin and move in an orbit within the nucleus.

Although the three-nucleon force has historically been considered to be of little significance when compared to the two-nucleon force, a growing number of recent studies have highlighted its importance. Now, this new study clarifies the mechanism of how the three-nucleon force enhances nuclear stability, and demonstrates that as the nucleus grows, the force gains in strength.

The researchers used advanced nuclear theory and supercomputer simulations to study the exchange of pions between three nucleons. They found that when two pions are exchanged between three nucleons, the nucleons are constrained in how they move and spin, with only four combinations possible. Their calculations revealed that one of these combinations, known as the "rank-1 component," plays a crucial role in promoting nuclear stability.

Increased stability occurs, the researchers explain, due to enhancing a process known as spin-orbit splitting. When nucleons spin and orbit in the same direction, the alignment of these nucleons leads to a reduction in energy. But when nucleons spin and orbit in opposing directions, these nucleons exist in a higher energy state. This means that nucleons "split" into different energy shells, providing the nucleus with a stable structure.

The supercomputer simulations showed that while the three-nucleon force increases the energy state of the nucleons with an aligned spin and orbit, it causes the nucleons with opposing spins and orbits to gain even more energy. This results in a larger energy gap between the shells, making the nuclei even more stable .

Part 1

Comment by Dr. Krishna Kumari Challa on February 3, 2025 at 9:54am

Large magma bodies found beneath dormant volcanoes

New research challenges the long-standing belief that active volcanoes have large magma bodies that are expelled during eruptions and then dissipate over time as the volcanoes become dormant.

Researchers used seismic waves to identify magma chambers beneath the surface of six volcanoes of various sizes and dormancy within the Cascade Range, which includes half of the U.S. volcanoes designated by the U.S. Geological Survey as "very high threat." The team found that all of the volcanoes, including dormant ones, have persistent and large magma bodies.

The study was published in Nature Geoscience .

The results are surprising given that some of these volcanoes, such as the Crater Lake volcano in Oregon, have not been active in millennia.

Regardless of eruption frequency, we see large magma bodies beneath many volcanoes, the researchers said. It appears that these magma bodies exist beneath volcanoes over their whole lifetime, not just during an active state.

The fact that more volcanoes have sustained magma bodies is an important consideration for how researchers may monitor and predict future volcanic activity.

Guanning Pang et al, Long-lived partial melt beneath Cascade Range volcanoes, Nature Geoscience (2025). DOI: 10.1038/s41561-024-01630-y

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