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Comment by Dr. Krishna Kumari Challa on July 13, 2024 at 11:41am

Comment by Dr. Krishna Kumari Challa on July 13, 2024 at 11:28am

First fossil chromosomes discovered
Scientists have discovered intact chromosomes preserved in the skin of a woolly mammoth (Mammuthus primigenius) that met its end some 50,000 years ago — a feat previously thought to be impossible. The team also revealed the spatial organization of the mammoth’s DNA molecules and the active genes in its skin, including one responsible for giving the animal its fuzzy appearance. The study is the first to report the 3D structure of an ancient genome.

https://www.cell.com/cell/fulltext/S0092-8674(24)00642-1?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867424006421%3Fshowall%3Dtrue

Comment by Dr. Krishna Kumari Challa on July 13, 2024 at 10:48am

The study pinpoints potential targets for preventing or treating muscle weakness related to brain inflammation. The researchers found that IL-6 activates what is called the JAK-STAT pathway in muscle, and this is what causes the reduced energy production of mitochondria.
Several therapeutics already approved by the FDA for other diseases can block this pathway. JAK inhibitors as well as several monoclonal antibodies against IL-6 are approved to treat various types of arthritis and manage other inflammatory conditions.

The researchers are not sure why the brain produces a protein signal that is so damaging to muscle function across so many different disease categories, though.
They speculate about possible reasons this process has stayed with us over the course of human evolution, despite the damage it does, it could be a way for the brain to reallocate resources to itself as it fights off disease. More research is  needed  to better understand this process and its consequences throughout the body.

Shuo Yang et al, Infection and chronic disease activate a systemic brain-muscle signaling axis, Science Immunology (2024). DOI: 10.1126/sciimmunol.adm7908. www.science.org/doi/10.1126/sciimmunol.adm7908

Part 2

Comment by Dr. Krishna Kumari Challa on July 13, 2024 at 10:45am

Scientists identify possible way to block muscle fatigue in long COVID, other diseases

Infections and neurodegenerative diseases cause inflammation in the brain. But for unknown reasons, patients with brain inflammation often develop muscle problems that seem to be independent of the central nervous system. Now, researchers  have revealed how brain inflammation releases a specific protein that travels from the brain to the muscles and causes a loss of muscle function.

The study, in fruit flies and mice, also identified ways to block this process, which could have implications for treating or preventing the muscle wasting sometimes associated with inflammatory diseases including bacterial infections, Alzheimer's disease and long COVID.

The study is published July 12 in the journal Science Immunology.

 The study suggests that when we get sick, messenger proteins from the brain travel through the bloodstream and reduce energy levels in skeletal muscle. This is more than a lack of motivation to move because we don't feel well. These processes reduce energy levels in skeletal muscle, decreasing the capacity to move and function normally.

To investigate the effects of brain inflammation on muscle function, the researchers modeled three different types of diseases—an E. coli bacterial infection, a SARS-CoV-2 viral infection and Alzheimer's.

When the brain is exposed to inflammatory proteins characteristic of these diseases, damaging chemicals called reactive oxygen species build up. The reactive oxygen species cause brain cells to produce an immune-related molecule called interleukin-6 (IL-6), which travels throughout the body via the bloodstream.

The researchers found that IL-6 in mice—and the corresponding protein in fruit flies—reduced energy production in muscles' mitochondria, the energy factories of cells.

Flies and mice that had COVID-associated proteins in the brain showed reduced motor function—the flies didn't climb as well as they should have, and the mice didn't run as well or as much as control mice.

The researchers saw similar effects on muscle function when the brain was exposed to bacterial-associated proteins and the Alzheimer's protein amyloid beta. They also saw evidence that this effect can become chronic. Even if an infection is cleared quickly, the reduced muscle performance remains many days longer in their experiments.

The bacterial brain infection meningitis is known to increase IL-6 levels and can be associated with muscle issues in some patients, for instance. Among COVID-19 patients, inflammatory SARS-CoV-2 proteins have been found in the brain during autopsy, and many long COVID patients report extreme fatigue and muscle weakness even long after the initial infection has cleared.

Patients with Alzheimer's disease also show increased levels of IL-6 in the blood as well as muscle weakness.

Part1

Comment by Dr. Krishna Kumari Challa on July 13, 2024 at 10:03am

How galaxies avoid early death

Galaxies avoid an early death because they have a "heart and lungs" which effectively regulate their "breathing" and prevent them from growing out of control, a new study suggests.

If they didn't, the universe would have aged much faster than it has and all we would see today is huge "zombie" galaxies teeming with dead and dying stars.

That's according to a new study published in the Monthly Notices of the Royal Astronomical Society, which investigates one of the great mysteries of the universe—why galaxies are not as large as astronomers would expect.

Something appears to be stifling their enormous potential by limiting the amount of gas they absorb to convert into stars, meaning that instead of endlessly growing, something inside resists what was thought to be the inevitable pull of gravity.

Now, astrophysicists  think they may have uncovered the secret. They suggest that galaxies could in fact control the rate at which they grow through how they "breathe."

In their analogy, the researchers compared the supermassive black hole at the center of a galaxy to its heart, and the two bi-polar supersonic jets of gas and radiation they emit to airways feeding a pair of lungs.

Pulses from the black hole—or "heart"—can lead to jet shock fronts oscillating back and forth along both jet axes, much like the thoracic diaphragm in the human body moves up and down inside a chest cavity to inflate and deflate both lungs.

This can result in jet energy being transmitted widely into the surrounding medium, just as we breathe out warm air, resulting in slowing galaxy gas-accretion and growth.

The phenomenon is similar to the terrestrial equivalent of sound and shock waves being produced when opening a bottle of champagne, the screech of a car, rocket exhausts and the puncture of pressurized enclosures.

These supersonic jets might help in inhibiting galaxy growth.

The researchers concluded that a galaxy's lifespan can be extended with the help of its "heart and lungs," where the supermassive black hole engine at its core helps inhibit growth by limiting the amount of gas collapsing into stars from an early stage. This, the researchers say, has helped create the galaxies we see today.

Without such a mechanism, galaxies would have exhausted their fuel by now and fizzled out, as some do in the form of "red and dead" or "zombie" galaxies.

Carl Richards et al, Simulations of Pulsed Over-Pressure Jets: Formation of Bellows and Ripples in Galactic Environments, Monthly Notices of the Royal Astronomical Society (2024). DOI: 10.1093/mnras/stae1498

Comment by Dr. Krishna Kumari Challa on July 12, 2024 at 11:20am

Monkey malaria is infecting people

Malaysia was on the brink of eliminating malaria – then a new parasite swung out of the jungle

A new malaria parasite comes from monkeys. With thousands already infected, experts fear it could one day spread between humans.

Malaria has been eliminated in Malaysia, but another variety is spilling out from the rainforest and infecting people: monkey malaria. Around 25,000 people have been infected with the Plasmodium knowlesi parasite since 2011, which causes nausea, fever and sometimes death. Deforestation has driven a spike in cases, pushing monkeys, mosquitoes and people into closer proximity. The disease isn’t limited to southeast Asia, and as it spreads so too does the chance that monkey malaria will adapt to be spread between humans.

https://www.telegraph.co.uk/global-health/science-and-disease/monke...

Comment by Dr. Krishna Kumari Challa on July 12, 2024 at 10:58am

Muscle fibers are composed of many components, such as various proteins, cell nuclei, organelles such as mitochondria, and molecular motors such as myosin that convert chemical fuel into motion and drive muscle contraction.
All of these components form a porous network that is bathed in water. So an appropriate, coarse-grained description for muscle is that of an active sponge, say the researchers.
But the squeezing process takes time to move water around, so the researchers suspected that this movement of water through the muscle fiber set an upper limit on how rapidly a muscle fiber can twitch.

To test their theory, they modeled muscle movements in multiple organisms across mammals, insects, birds, fish and reptiles, focusing on animals that use muscles for very fast motions. They found that muscles that produce sound, such as the rattle in a rattlesnake's tail, that can contract ten to hundreds of times per second typically don't rely on fluid flows. Instead, these contractions are controlled by the nervous system and are more strongly dictated by molecular properties, or the time it takes for molecular motors within cells to bind and generate forces.
But in smaller organisms, such as flying insects who are beating their wings a few hundred to a thousand times per second, these contractions are too fast for neurons to directly control. Here fluid flows are more important.
In these cases, the researchers found that fluid flows within the muscle fiber are important and their mechanism of active hydraulics is likely to limit the fastest rates of contraction.
The researchers also found that when muscle fibers act as an active sponge, the process also causes the muscles to act as an active elastic engine. When something is elastic, such as a rubber band, it stores energy as it tries to resist deformation. Imagine holding a rubber band between two fingers and pulling it back.

When you release the rubber band, the band also releases the energy stored when it was being stretched. In this case, energy is conserved—a basic law of physics that dictates that the amount of energy within a closed system should remain the same over time.
But when muscle converts chemical fuel into mechanical work, it can produce energy like an engine, violating the law of the conservation of energy. In this case, muscle shows a new property called "odd elasticity," where its response when squashed in one direction versus another is not mutual.

Unlike the rubber band, when muscle contracts and relaxes along its length, it also bulges out perpendicularly, and its energy does not stay the same. This allows muscle fibers to generate power from repetitive deformations, behaving as a soft engine.

These results are in contrast to prevailing thought, which focuses on molecular details and neglects the fact that muscles are long and filamentous, are hydrated, and have processes on multiple scales.
All together, our results suggest a revised view of how muscle functions is essential to understand its physiology. This is also crucial to understanding the origins, extent and limits that underlie the diverse forms of animal movement.

Suraj Shankar et al, Active hydraulics and odd elasticity of muscle fibres, Nature Physics (2024). DOI: 10.1038/s41567-024-02540-x

Part 2

Comment by Dr. Krishna Kumari Challa on July 12, 2024 at 10:53am

How water controls the speed of muscle contraction

The flow of water within a muscle fiber may dictate how quickly muscle can contract, according to a new study.

Nearly all animals use muscle to move, and it's been known for a long time that muscle, like all other cells, is composed of about 70% water. But researchers don't know what sets the range and upper limits of muscle performance. Previous research into how muscle works focused only on how it worked on a molecular level rather than how muscle fibers are shaped, that they are three-dimensional and are full of fluid.

Researchers now created a theoretical model of water's role in muscle contraction and found that how fluid moves through a muscle fiber determines how quickly a muscle fiber can contract.

They also found that muscle exhibits a new kind of elasticity called odd elasticity that allows muscle to generate power using three dimensional deformations, shown in a common observation that when a muscle fiber contracts lengthwise, it also bulges perpendicularly. Their results are published in the journal Nature Physics.

These results suggest that even such basic questions as how quickly muscle can contract or how many ways muscle can generate power have new and unexpected answers when one takes a more integrated and holistic view of muscle as a complex and hierarchically organized material rather than just a bag of molecules.

Part 1

Comment by Dr. Krishna Kumari Challa on July 12, 2024 at 9:29am

What made this bacterial glass different to other glasslike substances was the spontaneous formation of "microdomains" and the collective motion of the bacteria within these areas. These occurred where groups of the rod-shaped E. coli became aligned the same way.

The researchers were also surprised that the way the bacteria vitrify (turn into a glasslike state) apparently violates a physical law of typical thermal systems. What we characteristically know as glass, including colloidal glass, is classed as thermal glass. However, recently researchers have started to explore glassy states, like the one reported in this paper, which aren't considered thermal glass but share many of the same properties.

"Collections of 'self-propelled particles' like we see here have recently been regarded as a new kind of material called active matter, which is currently a hot topic and shows great potential.

Hisay Lama et al, Emergence of bacterial glass, PNAS Nexus (2024). DOI: 10.1093/pnasnexus/pgae238

Part 2

Comment by Dr. Krishna Kumari Challa on July 12, 2024 at 9:28am

Densely packed E. coli form an immobile material similar to colloidal glass, research shows

Dense E. coli bacteria have several similar qualities to colloidal glass, according to new research at the University of Tokyo. Colloids are substances made up of small particles suspended within a fluid, like ink for example. When these particles become higher in density and more packed together, they form a "glassy state."

When researchers multiplied E. coli bacteria within a confined area, they found that they exhibited similar characteristics. More surprisingly, they also showed some other unique properties not typically found in glass-state materials.

This study, which is published in PNAS Nexus, contributes to the understanding of glassy "active matter," a relatively new field of materials research which crosses physics and life science.

In the long term, the researchers hope that these results will contribute to developing materials with new functional capabilities, as well as aiding our understanding of biofilms (where microorganisms stick together to form layers on surfaces) and natural bacterial colonies.

Researchers have now found that the bacteria E. coli can behave in a similar way.

Since bacteria are very different from what we know of as glass, it was surprising that many of the statistical properties of glassy materials were the same for bacteria.

In this experiment, As the number of E. coli increased, they became caged in by their neighbors, restricting their ability to swim freely. Over time, they transitioned to a glassy state. This transition is similar to glass formation, as the researchers noted a rapid slowdown of movement, the caged-in effect and dynamic heterogeneity (whereby molecules travel longer distances in some areas but hardly move in others).

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