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Comment by Dr. Krishna Kumari Challa on August 6, 2024 at 8:31am

New biomaterial regrows damaged cartilage in joints

scientists have developed a new bioactive material that successfully regenerated high-quality cartilage in the knee joints of a large-animal model.

Although it looks like a rubbery goo, the material is actually a complex network of molecular components, which work together to mimic cartilage's natural environment in the body.

In the new study, the researchers applied the material to damaged cartilage in the animals' knee joints. Within just six months, the researchers observed evidence of enhanced repair, including the growth of new cartilage containing the natural biopolymers (collagen II and proteoglycans), which enable pain-free mechanical resilience in joints.

Stupp, Samuel I., A bioactive supramolecular and covalent polymer scaffold for cartilage repair in a sheep model, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2405454121

Comment by Dr. Krishna Kumari Challa on August 6, 2024 at 8:25am

Streetlights running all night makes leaves so tough that insects can't eat them, threatening the food chain

Light pollution disrupts circadian rhythms and ecosystems worldwide—but for plants, dependent on light for photosynthesis, its effects could be profound. Now scientists writing in Frontiers in Plant Science have found that exposure to high levels of artificial light at night makes tree leaves grow tougher and harder for insects to eat, threatening urban food chains.

Compared to natural ecosystems, tree leaves in most urban ecosystems generally show little sign of insect damage. Scientists were curious as to why. Their observations show that   in two of the most common tree species in Beijing, artificial light at night led to increased leaf toughness and decreased levels of leaf herbivory.

Artificial light has increased levels of night-time brightness by almost 10%: most of the world's population experiences light pollution every night. Because plant properties affect their interactions with other plants and animals, any changes to plants caused by artificial light could have a significant impact on the ecosystem.

Leaves that are free of insect damage may bring comfort to people, but not insects. Herbivory is a natural ecological process that maintains the biodiversity of insects.

The scientists suspected that plants experiencing high levels of artificial light would focus on defense rather than growth, producing tougher leaves with more chemical defense compounds. 

In their experiments,  they  found that the more intense the light, the more frequently they encountered leaves that showed no signs at all of herbivory.

It is possible that trees exposed to artificial light at night may extend their photosynthesis duration. Additionally, these leaves might allocate a greater proportion of resources to structural compounds, such as fibers, which could lead to an increase in leaf toughness.

Lower levels of herbivory imply lower abundances of herbivorous insects, which could in turn result in lower abundances of predatory insects, insect-eating birds, and so on. 

If there 're less pollinating insects, that would also affect the fruit yield.

 Artificial light at night decreases leaf herbivory in typical urban areas, Frontiers in Plant Science (2024). DOI: 10.3389/fpls.2024.1392262

Comment by Dr. Krishna Kumari Challa on August 6, 2024 at 8:10am

Researchers use vibrations from traffic to measure underground soil moisture

Researchers have developed a new method to measure soil moisture in the shallow subterranean region between the surface and underground aquifers. This region, called the vadose zone, is crucial for plants and crops to obtain water through their roots.

However, measuring how this underground moisture fluctuates over time and between geographical regions has traditionally relied on satellite imaging, which only gives low-resolution averages and cannot penetrate below the surface. Additionally, moisture within the vadose zone changes rapidly—a thunderstorm can saturate a region that dries out a few days later.

The new method relies upon seismic technology that normally measures how the ground shakes during earthquakes. However, it can also detect the vibrations of human activity, like traffic. As these vibrations pass through the ground, they are slowed down by the presence of water—the more moisture, the slower the vibration moves. The new study measures the water content in the vadose zone through seismic rumblings from everyday traffic.

The new method is based on a technique pioneered in the  lab, called distributed acoustic sensing (DAS). With this technique, lasers are pointed into unused underground fiber-optic cables (like the kind that provides the internet).

As a seismic wave, or any kind of vibration, passes through the cable, the laser light bends and refracts. Measuring the wiggles in this laser light gives researchers information about the passing wave, making the 10-kilometer cable equivalent to a line of thousands of conventional seismic sensors.

The ability to measure vadose zone moisture in real time is crucial for managing water use and conservation efforts. 

Fiber-optic seismic sensing of vadose zone soil moisture dynamics, Nature Communications (2024).

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 9:28am

Scientists have known since the 70s that when multiple phages infect the same cell, it impacts the outcome of the infection. In this paper, they were able to take precise measurements.
The researchers were surprised to find that the entry of a phage's genetic material could be impeded by the other coinfecting phages. They found that when there were more phages attached to the surface of the cell, relatively fewer of them were able to enter.
Their data shows that the first stage of infection, phage entry, is an important step that was previously underappreciated. The researchers found that the coinfecting phages were impeding each other's entry by perturbing the electrophysiology of the cell.
The outermost layer of bacteria is constantly dealing with the movement of electrons and ions that are crucial for energy generation and transmitting signals in and out of the cell. Over the past decade, researchers have started realizing the importance of this electrophysiology in other bacterial phenomena, including antibiotic resistance. This paper opens a new avenue for research in bacterial electrophysiology—its role in phage biology.
By influencing how many phages actually enter, these perturbations affect the choice between lysis and lysogeny. This study also shows that entry can be impacted by environmental conditions such as the concentration of various ions.

 Thu Vu Phuc Nguyen et al, Coinfecting phages impede each other's entry into the cell, Current Biology (2024). DOI: 10.1016/j.cub.2024.05.032

Part 2

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Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 9:24am

Coinfecting viruses obstruct each other's cell invasion

The process by which phages—viruses that infect and replicate within bacteria—enter cells has been studied for over 50 years. In a new study, researchers  have used cutting-edge techniques to look at this process at the level of a single cell.

The field of phage biology has seen an explosion over the last decade because more researchers are realizing the significance of phages in ecology, evolution, and biotechnology. 

This new work is unique because we looked at phage infection at the level of individual bacterial cells.

The process of phage infection involves the attachment of the virus to the surface of a bacterium. Following this, the virus injects its genetic material into the cell. After entering, a phage can either force the cell to produce more phages and eventually explode, a process called cell lysis, or the phage can integrate its genome into the bacterial one and remain dormant, a process called lysogeny. The outcome depends on how many phages are simultaneously infecting the cell. A single phage causes lysis, while infection by multiple phages results in lysogeny.

In the current study, the researchers wanted to ask whether the number of infecting phages that bind to the bacterial surface corresponds to the amount of viral genetic material that is injected into the cell. To do so, they fluorescently labeled both the protein shell of the phages and the genetic material inside. They then grew Escherichia coli, used different concentrations of infecting phages, and tracked how many of them were able to inject their genetic material into E. coli.

Part 1

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 9:20am

The researchers added these fast-joining RNA bases into a watery solution, provided an energy source and examined the length of the RNA molecules that formed. Their findings were sobering, as the resulting strands of up to five base pairs only survived for a matter of minutes.

The results were different, however, when the researchers started by adding short strands of pre-formed RNA. The free complementary bases quickly joined with this RNA in a process called hybridization. Double strands of three to five base pairs in length formed and remained stable for several hours.

The exciting part is that double strands lead to RNA folding, which can make the RNA catalytically active.

Double-stranded RNA therefore has two advantages: it has an extended lifespan in the primordial soup and serves as the basis for catalytically active RNA.

Another characteristic of double-stranded RNA could have helped bring about the origin of life. It is firstly important to note that RNA molecules can also form protocells. These are tiny droplets with an interior fully separated from the outside world. Yet, these protocells do not have a stable cell membrane and so easily merge with other protocells, which causes their contents to mix.

This is not conducive to evolution because it prevents individual protocells from developing a unique identity. However, if the borders of these protocells are composed of double-stranded DNA, the cells become more stable and merging is inhibited.

Christine M. E. Kriebisch et al, Template-based copying in chemically fuelled dynamic combinatorial libraries, Nature Chemistry (2024). DOI: 10.1038/s41557-024-01570-5

Part 2

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Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 9:17am

Researchers demonstrate mechanism that may have stabilized the first RNA molecules

The origins of life remain a major mystery. How were complex molecules able to form and remain intact for prolonged periods without disintegrating? A team at ORIGINS, a Munich-based Cluster of Excellence, has demonstrated a mechanism that could have enabled the first RNA molecules to stabilize in the primordial soup.

When two RNA strands combine, their stability and lifespan increase significantly. The work is published in the journal Nature Chemistry.

In all likelihood, life on Earth began in water, perhaps in a tide pool that was cut off from seawater at low tide but flooded by waves at high tide. Over billions of years, complex molecules like DNA, RNA and proteins formed in this setting before, ultimately, the first cells emerged. 

RNA is a fascinating molecule. It can store information and also catalyze biochemical reactions. Scientists therefore think that RNA must have been the first of all complex molecules to form.

The problem, however, is that active RNA molecules are composed of hundreds or even thousands of bases and are very unstable. When immersed in water, RNA strands quickly break down into their constituent parts—a process known as hydrolysis. So, how could RNA have survived in the primordial soup?

In laboratory testing, the researchers from TUM and LMU used a model system of RNA bases that join together more easily than naturally occurring bases in our cells today.

Part 1

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 8:39am

Scientists pin down the origins of the moon's tenuous atmosphere

While the moon lacks any breathable air, it does host a barely-there atmosphere. Since the 1980s, astronomers have observed a very thin layer of atoms bouncing over the moon's surface. This delicate atmosphere—technically known as an "exosphere"—is likely a product of some kind of space weathering. But exactly what those processes might be has been difficult to understand with any certainty.

Now, scientists  say they have identified the main process that formed the moon's atmosphere and continues to sustain it today. In a study appearing in Science Advances, the team reports that the lunar atmosphere is primarily a product of "impact vaporization."

In their study, the researchers analyzed samples of lunar soil collected by astronauts during NASA's Apollo missions.

Their analysis suggests that over the moon's 4.5-billion-year history its surface has been continuously bombarded, first by massive meteorites, then more recently, by smaller, dust-sized "micrometeoroids."

These constant impacts have kicked up the lunar soil, vaporizing certain atoms on contact and lofting the particles into the air. Some atoms are ejected into space, while others remain suspended over the moon, forming a tenuous atmosphere that is constantly replenished as meteorites continue to pelt the surface.

The researchers found that impact vaporization is the main process by which the moon has generated and sustained its extremely thin atmosphere over billions of years.

Nicole Nie, Lunar Soil Record of Atmosphere Loss over Eons, Science Advances (2024). DOI: 10.1126/sciadv.adm7074. www.science.org/doi/10.1126/sciadv.adm7074

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 8:26am

To examine the role of context in driving brain coupling, the team collected brain activity data and conversation transcripts from pairs of epilepsy patients during natural conversations.

The patients were undergoing intracranial monitoring using electrocorticography for unrelated clinical purposes at the New York University School of Medicine Comprehensive Epilepsy Center. Compared to less invasive methods like fMRI, electrocorticography records extremely high-resolution brain activity because electrodes are placed in direct contact with the surface of the brain.

Next, the researchers used the large language model GPT-2 to extract the context surrounding each of the words used in the conversations, and then used this information to train a model to predict how brain activity changes as information flows from speaker to listener during conversation.

Using the model, the researchers were able to observe brain activity associated with the context-specific meaning of words in the brains of both speaker and listener.

They showed that word-specific brain activity peaked in the speaker's brain around 250 ms before they spoke each word, and corresponding spikes in brain activity associated with the same words appeared in the listener's brain approximately 250 ms after they heard them.

Compared to previous work on speaker–listener brain coupling, the team's context-based approach model was better able to predict shared patterns in brain activity. This shows just how important context is, because it best explains the brain data. Large language models take all these different elements of linguistics like syntax and semantics and represent them in a single high-dimensional vector. This work shows that this type of unified model is able to outperform other hand-engineered models from linguistics.

A shared model-based linguistic space for transmitting our thoughts from brain to brain in natural conversations, Neuron (2024). DOI: 10.1016/j.neuron.2024.06.025. www.cell.com/neuron/fulltext/S0896-6273(24)00460-4

Part 2

Comment by Dr. Krishna Kumari Challa on August 3, 2024 at 8:24am

Brain activity associated with specific words is mirrored between speaker and listener during a conversation

When two people interact, their brain activity becomes synchronized, but it was unclear until now to what extent this "brain-to-brain coupling" is due to linguistic information or other factors, such as body language or tone of voice.

Researchers report August 2 in the journal Neuron that brain-to-brain coupling during conversation can be modeled by considering the words used during that conversation, and the context in which they are used.

Researchers could see linguistic content emerge word-by-word in the speaker's brain before they actually articulate what they're trying to say, and the same linguistic content rapidly reemerges in the listener's brain after they hear it.

To communicate verbally, we must agree on the definitions of different words, but these definitions can change depending on the context. For example, without context, it would be impossible to know whether the word "cold" refers to temperature, a personality trait, or a respiratory infection.

The contextual meaning of words as they occur in a particular sentence, or in a particular conversation, is really important for the way that we understand each other.

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