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Comment by Dr. Krishna Kumari Challa on September 12, 2024 at 10:38am

Multiple ways to evolve tiny knee bone could have helped humans walk upright

The evolution of bones in primates' knees could have implications for how humans evolved to walk upright, a new study has found.

Researchers from King's College London analyzed the presence of the lateral fabella, a bone in the knee the size of a sesame seed, in 93 different species of primates.

The lateral fabella is a sesamoid bone behind the knee which is twice as common in people with knee osteoarthritis. Sesamoids, like the kneecap, are small bones embedded in tendons or ligaments that are sometimes present within mammalian skeletons, which means they can be absent in some mammals, but present in others of the same species.

The findings are published in the journal Proceedings of the Royal Society B: Biological Sciences. They found that while most primates have these bones, they are often absent in hominoids, the group of primates that humans belong to alongside chimpanzees, gorillas, gibbons, and others.

Yet humans have evolved to have this bone differently from most primates and it is not found in all people. The researchers say this distinct evolutionary pathway of the fabella in humans could point to an evolutionary change that helped the ancestors of humans walk upright.

Using this bone in a new way could have helped early humans, like Australopithecus, go from walking on all fours to walking upright, the researchers say.

In the new study, scientists used statistical modeling to examine the presence of three sesamoid bones in the knee—the cyamella, medial fabella and lateral fabella—using research published over the last one hundred years.

The scientists discovered that primates with faballae were 50 times more likely to have ancestors who also had them. The team also found that the medial and lateral fabella almost always develop in pairs, except in rare cases like humans, who only have a lateral fabella.

Further analyses suggest hominoids may have evolved a way to grow fabellae different from other primates, which could explain why humans can grow a lateral fabella without a medial one, but other primates cannot. This could unite over a century of research, where scientists have debated how these bones evolved.

The distinct evolutionary pathway of the fabella 're-emerging' in humans could point to an evolutionary change that helped the ancestors of humans walk upright.

The evolution of the knee sesamoids in Primates: A systematic review and phylogenetic meta-analysis, Proceedings of the Royal Society B: Biological Sciences (2024). DOI: 10.1098/rspb.2024.0774. royalsocietypublishing.org/doi … .1098/rspb.2024.0774

Comment by Dr. Krishna Kumari Challa on September 12, 2024 at 9:24am

Scientists cool positronium to near absolute zero for antimatter research

Most atoms are made from positively charged protons, neutral neutrons and negatively charged electrons. Positronium is an exotic atom composed of a single negative electron and a positively charged antimatter positron. It is naturally very short-lived, but researchers  successfully cooled and slowed down samples of positronium using carefully tuned lasers.

The findings are published in the journal Nature. They hope this research will help others explore exotic forms of matter, and that such research might unlock the secrets of antimatter.

Some of our universe is missing. You may have heard such a bizarre statement if you've read much about cosmology in the last few decades. The reason scientists say this is because almost all the stuff we see in the universe is made from matter, including you and the planet you're standing on.

However, for a long time we've known about antimatter, which, as the name suggests, is sort of the opposite of regular matter, in that antimatter particles share the same mass and other properties of their matter counterparts, but have an opposite charge. When matter and antimatter particles collide, they annihilate, and it's widely believed they were created in equal amounts at the dawn of time. But that's not what we see now.

Modern physics only accounts for a part of the total energy of the universe. The study of antimatter might help us account for this discrepancy, and we've just taken a big step in this direction with our latest research.

Researchers have successfully slowed and cooled down exotic atoms of positronium, which is 50% antimatter. This means that, for the first time, it can be explored in ways previously impossible, and that will necessarily include a deeper study of antimatter.

Positronium is one of the few atoms made up entirely of only two elementary particles, which allows for such exact calculations.

Kosuke Yoshioka, Cooling positronium to ultralow velocities with a chirped laser pulse train, Nature (2024). DOI: 10.1038/s41586-024-07912-0. www.nature.com/articles/s41586-024-07912-0

Comment by Dr. Krishna Kumari Challa on September 12, 2024 at 9:02am

Archaeologists discover an ancient Neanderthal lineage that remained isolated for over 50,000 years

A fossilized Neanderthal discovered in a cave system in the Rhône Valley, France, represents an ancient and previously undescribed lineage that diverged from other currently known Neanderthals around 100,000 years ago and remained genetically isolated for more than 50,000 years.

Genomic analysis indicates that the Neanderthal, nicknamed "Thorin" in reference to the Tolkien character, lived between 42,000–50,000 years ago in a small, isolated community.

The discovery, published September 11 in the journal Cell Genomics, could shed light on the still-enigmatic reasons for the species' extinction and suggests that late Neanderthals had more population structure than previously thought.

Until now, the story has been that at the time of the extinction there was just one Neanderthal population that was genetically homogeneous, but now we know that there were at least two populations present at that time.

The Thorin population spent 50,000 years without exchanging genes with other Neanderthal populations.

We thus have 50 millennia during which two Neanderthal populations, living about ten days' walk from each other, coexisted while completely ignoring each other. This would be unimaginable for a Sapiens and reveals that Neanderthals must have biologically conceived our world very differently from us Sapiens.

 Long genetic and social isolation in Neanderthals before their extinction, Cell Genomics (2024). DOI: 10.1016/j.xgen.2024.100593. www.cell.com/cell-genomics/ful … 2666-979X(24)00177-0

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 8:13am

Long-term exercisers have 'healthier' belly fat, study reveals

People with obesity who are long-time exercisers have healthier belly fat tissue and can store fat there more effectively than nonexercisers with obesity, according to a new study from a team of researchers.

 

The study, "Long-term exercise training has positive effects on adipose tissue ...," appears Sept. 10 in Nature Metabolism.

The research team also grew fat tissue in the lab from cells collected from both exercisers and nonexercisers, and cells from the exercisers developed into a tissue that stored fat more effectively.

The findings indicate that in addition to being a means to expend calories, exercising regularly for several months to years seems to modify your fat tissue in ways that allows you to store your body fat more healthfully if or when you do experience some weight gain––as nearly everyone does as we get older.

They found that the exercisers had distinct structural and biological characteristics in their fat tissue that increased the capacity to store fat there. The nonexercisers did not have those characteristics. Specifically, the exercisers had more blood vessels, mitochondria and beneficial proteins, and less of a type of collagen that can interfere with metabolism and fewer cells that cause inflammation.

This matters because the healthiest place to store fat is the fat tissue just under the skin where the samples were taken, called subcutaneous adipose tissue. Increasing the capacity to store fat here through exercise reduces the need to store fat in unhealthy places, like in the fat tissue around the organs or in the organs themselves.

Cheehoon Ahn et al, Years of endurance exercise training remodel abdominal subcutaneous adipose tissue in adults with overweight or obesity, Nature Metabolism (2024). DOI: 10.1038/s42255-024-01103-x

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 8:00am

Researchers bend DNA strands with light, revealing a new way to study the genome

With the flick of a light, researchers have found a way to rearrange life's basic tapestry, bending DNA strands back on themselves to reveal the material nature of the genome.

Scientists have long debated about the physics of chromosomes—structures at the deepest interior of a cell that are made of long DNA strands tightly coiled around millions of proteins. Do they behave more like a liquid, a solid, or something in between?

Much progress in understanding and treating disease depends on the answer.

A research team has now developed a way to probe chromosomes and quantify their mechanical properties: how much force is required to move parts of it around and how well it snaps back to its original position.

The answer to the material question, according to their findings, is that in some ways the chromosome acts like an elastic material and in other ways it acts like a fluid. By leveraging that insight in exacting detail, the team was able to physically manipulate DNA in new and precisely controlled ways.

They published their findings in the journal Cell on August 20.

The key to the new method lies in the researchers' ability to generate tiny liquid-like droplets within a cell's nucleus. The droplets form like oil in water and grow larger when exposed to a specific wavelength of blue light.

Because the droplets are initiated at a programmable protein—a modified version of the protein used in the gene editing tool known as CRISPR—they can also attach the droplet to DNA in precise locations, targeting genes of interest.

With their ability to control this process using light, the team found a way to grow two droplets stuck to different sequences, merge the two droplets together, and finally shrink the resulting droplet, pulling the genes together as the droplet recedes. The entire process takes about 10 minutes.

Physically repositioning DNA in this way represents a completely new direction for engineering cells to improve health and could lead to new treatments for disease, according to the researchers. For example, they showed that they could pull two distant genes toward each other until the genes touch.

Established theory predicts this could lead to greater control over gene expression or gene regulation—life's most fundamental processes.

Amy R. Strom et al, Condensate interfacial forces reposition DNA loci and probe chromatin viscoelasticity, Cell (2024). DOI: 10.1016/j.cell.2024.07.034

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 7:12am

Psychologists argue conscientiousness outshines willpower in predicting success

According to some psychologists, the field of psychological science has a problem with the concept of self-control. It has named self-control both a "trait"—a key facet of personality involving attributes like conscientiousness, grit and the ability to tolerate delayed gratification—and a "state," a fleeting condition that can best be described as willpower. These two concepts are at odds with one another and are often confused, the authors report.

Conscientiousness  is the quality of wishing to do one's work or duty well and thoroughly.

Self-control is a cherished quality. People who have lots of it are celebrated and seen as morally righteous. 

Many studies find that people who score highly on various measures of conscientiousness do better than their peers academically and financially and tend to live healthier lives.

This led psychologists to conflate momentary will power with the other characteristics that make conscientious people successful, the researchers said.

People assumed that highly conscientious people simply engage their willpower more often than their less-conscientious peers. But this is not the case. Conscientious people do not control themselves more than others. In fact, studies have shown that they spend less time restraining wayward desires. This was a surprise when it was discovered more than a decade ago.

The misguided emphasis on willpower led to interventions designed to increase it, with the goal of also strengthening conscientiousness. This approach occasionally yielded some positive short-term results, the researchers said. But in the long term, such changes tend to erode.

People usually revert to their baseline levels of willpower and conscientiousness Willpower is generally fragile, unreliable and weak.

The science strongly suggests that other aspects of "trait self-control" are more likely to contribute to the lifelong benefits associated with this trait.

Perhaps it's their industriousness or organizational skills. Or maybe it's their ability to persist in pursuit of a goal.

Success in life might be the result of engaging less in day-to-day willpower and more in cold calculation before a temptation is ever met, the researchers said. Maybe conscientiousness is explained not by exerting willpower, but by avoiding the need to exert it in the first place.

Michael Inzlicht et al, The fable of state self-control, Current Opinion in Psychology (2024). DOI: 10.1016/j.copsyc.2024.101848

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 7:01am

Researchers find live fungi, bacteria and viruses high in the Earth's atmosphere

A team of climate, health and atmospheric specialists  has found abundant live fungi, bacteria and viruses high in the Earth's atmosphere. In their study published in the Proceedings of the National Academy of Sciences, the group collected air samples from altitudes of 1,000–3,000 meters.

Prior research has shown that dust can travel thousands of miles in the atmosphere—large amounts of dust from Africa are carried to both North and South America, for example. Prior research has also shown that microbes that attach to dust can be carried equally far.

For this new study, the researchers wondered how high in the atmosphere microbes might be found and whether they could survive the trip. To learn more, they chartered a small plane that carried them aloft over parts of Japan, where they collected air samples at altitudes of 1,000–3,000 meters near the planetary boundary. They also gathered weather data related to the air column in areas where they had flown.
In an air-controlled lab, they conducted a DNA analysis on the microbes found in the samples as a way to identify what they were and also which types. They found examples of fungi, bacteria and viruses, many of which, the team noted, are hazardous to human health.

They also found that many of the microbes were still viable—they grew cultures of them in lab dishes. In all, the team found 266 types of fungi and 305 types of bacteria.

The researchers noted that many of both types were of the kind that are often found in soil or plants. They suspect that due to the geographic location of the microbes, the height at which they were found and the speed of the winds carrying them, that the majority of them came from China, which meant they had traveled at least 2,000 kilometers.

The research team suggests that bio-pathogens are capable of traveling thousands of kilometers at high altitudes, possibly representing a way to spread diseases.

Xavier Rodó et al, Microbial richness and air chemistry in aerosols above the PBL confirm 2,000-km long-distance transport of potential human pathogens, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2404191121

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 6:57am

Longipteryx is part of a larger group of prehistoric birds called the enantiornithines, and this discovery marks the first time that scientists have found any stomach contents from an enantiornithine in China's Jehol Biota despite thousands of uncovered fossils.

"It's always been weird that we didn't know what they were eating, but this study also hints at a bigger picture problem in paleontology, that physical characteristics of a fossil don't always tell the whole story about what the animal ate or how it lived.
Since Longipteryx apparently wasn't hunting for fish, that leaves a question: what was it using its long, pointy beak and crazy-strong teeth for? The thick enamel is overpowered, it seems to be weaponized.
Weaponized beaks in hummingbirds have evolved at least seven times, allowing them to compete for limited resources. Clark suggested the hypothesis that perhaps Longipteryx's teeth and beak also served as a weapon, perhaps evolving under social or sexual selection.

Direct evidence of frugivory in the Mesozoic bird Longipteryx contradicts morphological proxies for diet, Current Biology (2024). DOI: 10.1016/j.cub.2024.08.012. www.cell.com/current-biology/f … 0960-9822(24)01124-2

Part 2

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Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 6:55am

Paleontologists discover fossil birds with teeth had seeds in their stomachs, indicating that they ate fruit

For paleontologists who study animals that lived long ago, fossilized remains tell only part of the story of an animal's life. While a well-preserved skeleton can provide hints at what an ancient animal ate or how it moved, irrefutable proof of these behaviors is hard to come by. But sometimes, scientists luck out with extraordinary fossils that preserve something beyond the animal's body.

In a study published in the journal Current Biology, researchers found fossilized seeds in the stomachs of one of the earliest birds. This discovery shows that these birds were eating fruits, despite a long-standing hypothesis that this species of bird feasted on fish (and more recent hypotheses it ate insects) with its incredibly strong teeth.

Longipteryx chaoyangensis lived 120 million years ago in what's now northeastern China. It's among the earliest known birds, and one of the strangest.

This bird is weird. It had a  long skull, and teeth only at the tip of its beak. 

Tooth enamel is the hardest substance in the body, and Longipteryx's tooth enamel is 50 microns thick. That's the same thickness of the enamel on enormous predatory dinosaurs like Allosaurus that weighed 4,000 pounds, but Longipteryx is the size of a bluejay. 

Longipteryx was discovered in 2000, and at the time, scientists suggested that its kingfisher-like elongated skull meant that it too hunted fish. However, this hypothesis has been challenged by a number of scientists.

There are other fossil birds, like Yanornis, that ate fish, and scientists know because specimens have been found with preserved stomach contents, and fish tend to preserve well. Plus, these fish-eating birds had lots of teeth, all the way along their beaks, unlike how Longipteryx only has teeth at the very tip of its beak.

However, no specimens of Longipteryx had been found with fossilized food still in their stomachs for scientists to confirm what it ate— until now.

Since Longipteryx lived in a temperate climate, it probably wasn't eating fruits year-round;  scientists suspect that it had a mixed diet which included things like insects when fruits weren't available.

Part 1

Comment by Dr. Krishna Kumari Challa on September 11, 2024 at 6:37am

New Zealand's kākāpō developed different feather colors to evade predatory birds, genome sequencing shows

Evolution: Aotearoa New Zealand's flightless parrot, the kākāpō, evolved two different color types to potentially help them avoid detection by a now-extinct apex predator , researchers report in the open-access journal PLOS Biology.

The kākāpō (Strigops habroptilus) is a nocturnal, flightless parrot endemic to New Zealand. It experienced severe population declines after European settlers introduced new predators. By 1995 there were just 51 individuals left, but intense conservation efforts have helped the species rebound to around 250 birds. Kākāpō come in one of two colors—green or olive—which occur in roughly equal proportions.

To understand how this color variation evolved and why it was maintained despite population declines, researchers analyzed genome sequence data for 168 individuals, representing nearly all living kākāpō at the time of sequencing. They identified two genetic variants that together explain color variation across all the kākāpō they studied.

Scanning electron microscopy showed that green and olive feathers reflect slightly different wavelengths of light because of differences in their microscopic structure. The researchers estimate that olive coloration first appeared around 1.93 million years ago, coinciding with the evolution of two predatory birds: Haast's eagle and Eyles' harrier.

Computer simulations suggest that whichever color was rarer would have been less likely to be detected by predators, explaining why both colors persisted in the kākāpō population over time.

The results suggest that kākāpō coloration evolved due to pressure from apex predators that hunted by sight. This variation has remained even after the predators went extinct, around 600 years ago.

The authors argue that understanding the origins of kākāpō coloration might have relevance to the conservation of this critically endangered species. They show that without intervention, kākāpō color variation could be lost within just 30 generations, but it would be unlikely to negatively impact the species today.

Urban L, Santure AW, Uddstrom L, Digby A, Vercoe D, Eason D, et al. (2024) The genetic basis of the kākāpō structural color polymorphism suggests balancing selection by an extinct apex predator. PLoS Biology (2024). DOI: 10.1371/journal.pbio.3002755

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