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Comment by Dr. Krishna Kumari Challa on July 29, 2024 at 9:01am

Signs of Ancient Life on Mars?

NASA’s Perseverance rover has made very compelling observations in a Martian rock that, with further study, could prove that life was present on Mars in the distant past – but how can we determine that from a rock, and what do we need to do to confirm it? Morgan Cable, a scientist on the Perseverance team, takes a closer look.

Comment by Dr. Krishna Kumari Challa on July 28, 2024 at 12:11pm

Neuroscientists discover brain circuitry of placebo effect for pain relief

The placebo effect is very real. Some placebo effects are so strong that individuals are convinced they received a real treatment meant to help them. This we've known for decades, as seen in real-life observations and the best double-blinded randomized clinical trials researchers have devised for many diseases and conditions, especially pain. And yet, how and why the placebo effect occurs has remained a mystery. Now, neuroscientists have discovered a key piece of the placebo effect puzzle.

 And the placebo effect—feeling better even though there was no "real" treatment—has been documented as a very real phenomenon for decades.

It is the human experience, in the face of pain, to want to feel better. As a result—and in conjunction with millennia of evolution—our brains can search for ways to help us feel better.

It releases chemicals, which can be measured.

Published now in Nature, researchers discovered a pain control pathway that links the cingulate cortex

 in the front of the brain, through the pons region of the brainstem, to cerebellum in the back of the brain.

They showed that certain neurons and synapses along this pathway are highly activated when mice expect pain relief and experience pain relief, even when there is no medication involved.

That neurons in our cerebral cortex communicate with the pons and cerebellum to adjust pain thresholds based on our expectations is both completely unexpected, given our previous understanding of the pain circuitry, and incredibly exciting. These results do open the possibility of activating this pathway through other therapeutic means, such as drugs or neurostimulation methods to treat pain.

This research provides a new framework for investigating the brain pathways underlying other mind-body interactions and placebo effects beyond the ones involved in pain.

Grégory Scherrer, Neural circuit basis of placebo pain relief, Nature (2024). DOI: 10.1038/s41586-024-07816-z. www.nature.com/articles/s41586-024-07816-z

Comment by Dr. Krishna Kumari Challa on July 28, 2024 at 12:11pm

Biologists discover human-infecting parasite produces sterile soldiers like ants and termites

New research from scientists finds a tiny freshwater parasite known to cause health problems in humans defends its colonies with a class of soldiers that cannot reproduce.

The discovery, published in the Proceedings of the National Academy of Sciences vaults this species of parasitic flatworm into the ranks of complex animal societies such as ants, bees and termites, which also have distinct classes of workers and soldiers that have given up reproduction to serve their colony.

When it gets into humans, usually via the consumption of raw or undercooked fish, this species of flatworm, Haplorchis pumilio, can cause gastrointestinal issues and, in severe cases, stroke or heart attack. Fully cooking fish or freezing any meant to be eaten raw for at least one week is enough to kill the trematodes, per Food and Drug Administration guidelines.

While there are no specific statistics for Haplorchis pumilio, foodborne trematode infections cause 2 million life years lost to disability and death worldwide every year.

Unlike bees and termites, the colonies of this species of flatworm are not underground or in a tree hollow, but inside the body of a live snail. The parasites don't kill the snail, but instead siphon off nutrients for years as they pump out free-swimming clones that search for fish, the flatworms' next host in their complex life cycle.

These flatworms could become invaluable tools to probe fundamental questions of sociobiology—like, 'how does this kind of social organization evolve?

This study is the first evidence for trematode soldiers that are so physically specialized to their task that they lack any reproductive tissues and appear permanently incapable of reproduction.

 Daniel C. G. Metz et al, The physical soldier caste of an invasive, human-infecting flatworm is morphologically extreme and obligately sterile, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2400953121

Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 12:35pm

Komodo Dragon Teeth Have Iron Caps For Sharpness, Scientists Discover

As if komodo dragons weren't amazing enough, these giant lizards literally have teeth of iron.

A new study of these formidable predators' chompers has revealed concentrated deposits of iron along the serrated tearing edges and the tips of their teeth, helping to keep them razor-sharp for tearing the flesh from the prey they devour.

Although many vertebrates have iron enhancements in their teeth, komodo dragons (Varanus komodoensis) and other similar species with serrated teeth, called ziphodonts, represent the most striking examples found to date.
In fact, so much iron is concentrated along the sharp edges of komodo teeth that they are tinted orange.

Never before has iron been found so localized along the cutting edge of a vertebrate tooth. This suggests that a stronger cutting edge confers a competitive advantage, and may yield insights into how some of the fiercest dinosaurs devoured their food.

https://www.nature.com/articles/s41559-024-02477-7

Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 9:51am

Scientists control bacterial mutations to preserve antibiotic effectiveness

Scientists have discovered a way to control mutation rates in bacteria, paving the way for new strategies to combat antibiotic resistance.

Antibiotics are given to kill bad bacteria; however, with just one mutation a bacteria can evolve to become resistant to that antibiotic, making common infections potentially fatal.

The new research, published recently in the journal PLOS Biology, used high-performance computing to simulate more than 8,000 years of bacterial evolution, allowing scientists to predict mechanisms that control mutation rates.

They then made more than 15,000 cultures of E. coli in lab conditions to test their predictions—that's so many that if you lined up all of the bacteria in this study, they would stretch 860,000 km, or wrap around the Earth more than 20 times.

The tests revealed that bacteria living in a lowly populated community are more prone to developing antibiotic resistance due to a naturally occurring DNA-damaging chemical, peroxide. In crowded environments, where cells are more densely packed, bacteria work collectively to detoxify peroxide, reducing the likelihood of mutations that lead to antibiotic resistance.

The finding could help develop "anti-evolution drugs" to preserve antibiotic effectiveness by limiting the mutation rates in bacteria.

By understanding the environmental conditions that influence mutation rates, we can develop strategies to safeguard antibiotic effectiveness. This new study shows that bacterial mutation rates are not fixed and can be manipulated by altering their surroundings, which is vital on our journey to combat antibiotic resistance.

Peroxide, a chemical found in many environments, is key to this process. When E. coli populations become denser, they work together to lower peroxide levels, protecting their DNA from damage and reducing mutation rates. The study showed that genetically modified E. coli that is unable to break down peroxide had the same mutation rates, no matter the population size. However, when helper cells that could break down peroxide were added, the mutation rate in these genetically modified E. coli decreased.

Rowan Green et al, Collective peroxide detoxification determines microbial mutation rate plasticity in E. coli, PLOS Biology (2024). DOI: 10.1371/journal.pbio.3002711

Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 9:44am

New aerospace and building materials could repair themselves thanks to fungi and bacteria

Researchers are using biological matter to create unique new materials that can adapt to their environment and repair themselves.

Researchers are developing what they call "living materials," for use in the aerospace and transportation sectors. These living materials are, precisely as they sound, literally alive. They contain microorganisms such as fungi and bacteria, which give them the capacity to sustain their integrity and self-healing.

The goal is to make engineered structures that can behave like living organisms, able to sense and adapt to mechanical stresses.

The material they are developing is a composite that combines living fungi cells and wood. It consists of a hydrogel and mycelium, a root-like structure of a fungus that normally lives underground.

They chose to work with fungi because fungus is a really robust organism, it is tolerant to harsh conditions and is relatively easy to cultivate. 

Moreover, fungal cells have a great ability to connect. Mycelium can grow a vast sensing network that allows it to send signals throughout the organism. That means the scientists can distribute only a few cells throughout the material, and these cells will reconnect and form a sensing network.

Biological materials could help to improve the performance and durability of critical structures used in areas like aerospace and transportation.

These materials are very lightweight and more sustainable than currently used materials. 

Sources: 

• AM-IMATE
• ARCHISKIN
• EU research and innovation for chemicals and advanced materials

Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 9:34am

Ice 0: Researchers discover a new mechanism for ice formation

Ice is far more complicated than most of us realize, with over 20 different varieties known to science, forming under various combinations of pressure and temperature. The kind we use to chill our drinks is known as ice I, and it's one of the few forms of ice that exist naturally on Earth.

Researchers have recently discovered another type of ice: ice 0, an unusual form of ice that can seed the formation of ice crystals in supercooled water.

The formation of ice near the surface of liquid water can start from tiny crystal precursors with a structure similar to a rare type of ice, known as ice 0.

In a study published in Nature Communications, researchers showed that these ice 0-like structures can cause a water droplet to freeze near its surface rather than at its core. This discovery resolves a longstanding puzzle and could help redefine our understanding of how ice forms.

Crystallization of ice, known as ice nucleation, usually happens heterogeneously, or in other words, at a solid surface. This is normally expected to happen at the surface of the water's container, where liquid meets solid.

However, this new research shows that ice crystallization can also occur just below the water's surface, where it meets the air. Here, the ice nucleates around small precursors with the same characteristic ring-shaped structure as ice 0.

Simulations have shown that a water droplet is more likely to crystallize near the free surface under isothermal conditions. This resolves a longstanding debate about whether crystallization occurs more readily on the surface or internally.

Ice 0 precursors have a structure very similar to supercooled water, allowing water molecules to crystallize more readily from it, without needing to directly form themselves into the structure of regular ice.

The tiny ice 0 precursors are formed spontaneously, as a result of negative pressure effects caused by the surface tension of water. Once crystallization begins from these precursors, structures similar to ice 0 quickly rearrange themselves into the more familiar ice I.

Surface-induced water crystallization driven by precursors formed in negative pressure regions, Nature Communications (2024). DOI: 10.1038/s41467-024-50188-1

Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 9:07am

Birds are a specialized group of dinosaurs— the earliest known bird, Archaeopteryx, lived 140 million years ago. A sub-group of birds called Neornithes evolved 80 million years ago, and this group became the only birds (and dinosaurs) to survive the mass extinction 66 million years ago.
All modern birds are members of Neornithes.The model produced by researchers now suggests that the common ancestor of all Neornithes, 80 million years ago, had iridescent feathers that still glitter across the bird family tree.
Researchers found fossil evidence of iridescent birds and other feathered dinosaurs before, by examining fossil feathers and the preserved pigment-producing structures in those feathers. So we know that iridescent feathers existed back in the Cretaceous—those fossils help support the idea from this new model that the ancestor of all modern birds was iridescent too.
The discovery that the first Neornithes was likely iridescent could have important implications for paleontology.

Transitions between colour mechanisms affect speciation dynamics and range distributions of birds, Nature Ecology & Evolution (2024). DOI: 10.1038/s41559-024-02487-5

Part 2

Comment by Dr. Krishna Kumari Challa on July 27, 2024 at 9:03am

Scientists figure out why there are so many colorful birds in the tropics and how these colours spread over time

The color palette of the birds you see out your window depends on where you live. If you're far from the Equator, most birds tend to have drab colors, but the closer you are to the tropics, you'll probably see more and more colorful feathers.

Scientists have long been puzzled about why there are more brilliantly-colored birds in the tropics than in other places, and they've also wondered how those brightly-colored birds got there in the first place: that is, if those colorful feathers evolved in the tropics, or if tropical birds have colorful ancestors that came to the region from somewhere else.

In a study published in the journal Nature Ecology and Evolution, scientists built a database of 9,409 birds to explore the spread of color across the globe.

They found that iridescent, colorful feathers originated 415 times across the bird tree of life, and in most cases, arose outside of the tropics– and that the ancestor of all modern birds likely had iridescent feathers, too.

There are two main ways that color is produced in animals: pigments and structures. Cells produce pigments like melanin, which is responsible for black and brown coloration. Meanwhile, structural color comes from the way light bounces off different arrangements of cell structures. Iridescence, the rainbow shimmer that changes depending how light hits an object, is an example of structural colour.

Tropical birds get their colors from a combination of brilliant pigments and structural color.

Researchers  combed through photographs, videos, and even scientific illustrations of 9,409 species of birds— the vast majority of the 10,000-ish living bird species known to science. The researchers kept track of which species have iridescent feathers, and where those birds are found.

The scientists then combined their data on bird coloration and distribution with a pre-existing family tree, based on DNA, showing how all the known bird species are related to each other. They fed the information to a modeling system to extrapolate the origins and spread of iridescence.

Given how modern species are related to each other and where they're found, and overall patterns of how species form and how traits like colors change over time, the modeling software determined the most likely explanation for the bird colors we see today: colorful birds from outside the tropics often came to the region millions of years ago, and then branched out into more and more different species. The model also revealed a surprise about the ancestor of all modern birds.

Part 1

Comment by Dr. Krishna Kumari Challa on July 26, 2024 at 11:59am

Hungry fungi clean up contamination

A growing number of biotech companies are investing in fungal treatments that break down environmental contaminants — from.... Fungi tend to be better than bacteria at tackling large, complex chemicals like the hydrocarbons in many plastics, although this sometimes requires combining different strains of fungi to perform different steps of the process. They can be applied directly to contaminated soil or water, as well as used to break down plastic-based garbage like carpets or mattresses.

https://www.nature.com/articles/s41587-024-02315-y.epdf?sharing_tok...

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