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Comment by Dr. Krishna Kumari Challa on April 29, 2023 at 8:26am

A neural circuit that suppresses male aggression when an opponent is physically advantaged

For decades, neuroscientists have been trying to understand the neural mechanisms underpinning different social behaviors, including aggression. Aggressive, violent, or confrontational behaviors are common among humans and many animal species, yet the neural processes supporting or suppressing these behaviors have not been fully unveiled yet.

Researchers recently unveiled an area in the hypothalamus, brain region influencing the nervous system and the release of hormones, that suppresses aggression in male mice when they are confronting a stronger or physically "superior" opponent. Their findings, published in Nature Neuroscience, shed some new light on the neural pathways modulating aggression in animals and potentially also humans.

Previously, scientists found that VMHvl is an essential region for generating aggression.

While conducting their studies, researchers realized that rostral (i.e., frontal) and caudal (i.e., posterior) parts of the MPOA, an area of the hypothalamus, responded differently while mice were socially interacting with each other. They found that the caudal MPOA tended to be more active during interactions between two males than during interactions between male and female mice.

When they manipulated the caudal MPOA, they found that aggression is strongly suppressed. They then considered the potential situation under which male aggression towards another male could be suppressed. This led them to discover that cMPOA cell activity increases when a male encounters a stronger opponent.

To conduct their recent experiments, the researchers used a combination of optogenetic and chemogenetic techniques. They recorded calcium activity in the mice's brain using fiber photometry, an optogenetic technique, and also collected patch clamp recordings in slices of the mouse brain.

Using optogenetic techniques, they also inhibited or activated cells in the cMPOA of living male mice and observed their resulting behaviour during social interactions. Interestingly, the inhibition of these cells appeared to increase the male mice's aggression towards other males, while activating them decreased the mice's aggressive behaviours.

These findings suggest that cMPOA cells naturally suppress aggression.

Overall, the findings gathered in this study suggest that the posterior part of the MPOA can significantly influence aggressive behaviour between male mice. Specifically, this area of the hypothalamus appears to reduce aggression towards a stronger male opponent, by suppressing activity in the VMHvl.

Dongyu Wei et al, A hypothalamic pathway that suppresses aggression toward superior opponents, Nature Neuroscience (2023). DOI: 10.1038/s41593-023-01297-5

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Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 12:03pm

Four different plastic models were used to study the role of the plastic particle' corona. The simulations showed that particles with a protein corona couldn't enter the barrier. However, those with a cholesterol corona could cross, even if they couldn't progress deeper into brain tissue.

The results raise the possibility that plastic can be transported across the membrane and into the brain tissue with the help of the right molecular cocktail. Knowing the fundamental mechanisms is an important first step in managing their harmful effects.

https://www.mdpi.com/2079-4991/13/8/1404

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 12:03pm

Plastic Particles Found in The Brains of Mice Just Two Hours After They Ate

Thanks to their flexibility, durability, and affordability, plastics have oozed their way into just about every aspect of our lives. When these items do eventually break down, the resulting micro- and nanoplastics (MNPs) can harm wildlife, the environment, and ourselves. MNPs have been found in blood, lungs, and placenta, and we know that they can get into our bodies through the food and liquids we consume.

A new study by a team of researchers from Austria, the US, Hungary, and the Netherlands has found MNPs can reach the brain a few hours after being eaten, possibly thanks to the way other chemicals stick to their surface.

Not only is the speed alarming, the very possibility of tiny polymers sliding into our nervous system raises some serious alarm bells.

In the brain, plastic particles could increase the risk of inflammation, neurological disorders or even neurodegenerative diseases such as Alzheimer's or Parkinson's.

In the study, tiny fragments of MNPs orally administered to mice were detectable in their brains in as little as two hours. But how do MNPs get through the blood-brain barrier, which is supposed to keep the brain safe?

As a system of blood vessels and tightly packed surface tissue, the blood-brain barrier helps shield our brains from potential threats by blocking the passage of toxins and other undesirables, while permitting more useful substances across. It stands to reason that plastic particles would count as a material to keep well and truly out of the brain's sensitive tissues.

With the help of computer models, scientists discovered that a certain surface structure (biomolecular corona) was crucial in enabling plastic particles to pass into the brain.

To verify that the particles truly can enter the brain, polystyrene (a common plastic used in food packaging) MNPs in three sizes (9.5, 1.14, and 0.293 micrometers) were labeled with fluorescent markers and pretreated in a mixture similar to digestive fluid before being fed to mice.

The researchers  found specific nanometer-sized green fluorescent signals in the brain tissue of MNP-exposed mice after only two hours!

Only 0.293 micrometer sized particles were able to be taken up from the gastrointestinal tract and to penetrate the blood brain barrier.

How these tiny, blanketed plastics cross cell barriers in the body is complicated and depends on factors like particle size, charge, and cell type.

Tinier plastic particles have a higher surface area-to-volume ratio, making them more reactive and potentially more hazardous than larger microplastics. This reactivity is thought to allow the small bits of plastic to gather other molecules around them, hugging them tight with molecular forces to form a durable cloak called a corona.

Part 1

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 11:30am

How shading crops with solar panels can improve farming, lower food...

If you have lived in a home with a trampoline in the backyard, you may have observed the unreasonably tall grass growing under it. This is because many crops, including these grasses, actually grow better when protected from the sun, to an extent.

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We need to talk about gene-therapy prices

At US$3.5 million per treatment, the haemophilia gene therapy Hemgenix is the most expensive drug in the world. Other gene therapies are expected to carry similarly eye-watering p.... This puts them out of the reach of many who need them and diminishes government funders’ willingness to pay for related research. “Researchers, especially health economists, must work urgently with industry and governments to find a more affordable funding model,” argues a Nature editorial.

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 11:27am

Using microbes to get more out of mining waste

Researchers have developed a new mining technique which uses microbes to recover metals and store carbon in the waste produced by mining. Adopting this technique of reusing mining waste, called tailings, could transform the mining industry and create a greener and more sustainable future.

Tailings are a by-product of mining. They are the fine-grained waste materials left after extracting the target ore mineral, which are then stacked and stored. This method is called dry-stack tailing.

Over time, mining practices have evolved and become more efficient. But the climate crisis and rising demand for critical minerals require the development of new ore removal and processing technologies.

Old tailings contain higher amounts of critical minerals that can be extracted with the help of microbes through a process called bioleaching. The microbes help break down the ore, releasing any valuable metals that weren't fully recovered in an eco-friendly way that is much faster than natural biogeochemical weathering processes.

We can now take tailings that were produced in the past and recover more resources from those waste materials and, in doing so, also reduce the risk of residual metals entering into local waterways or groundwater.

In addition to improving resource recovery, the microbes capture carbon dioxide from the air and store it within the mine tailings as new minerals. This process aids in offsetting some of the emissions released while the mine was active and helps stabilize the tailings.

Microbial mineral carbonation could offset more than 30 per cent of a mine sites annual greenhouse gas emissions if applied to an entire mine. In addition, this microbial-driven technique gives value to historical mine tailings that are otherwise considered industrial waste.

Jenine McCutcheon et al, Microbially mediated carbon dioxide removal for sustainable mining, PLOS Biology (2023). DOI: 10.1371/journal.pbio.3002026

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 11:13am

Researchers also examined more than 10,000 genetic deletions specific to humans using both Zoonomia data and experimental analysis, and linked some of them to the function of neurons.

Other Zoonomia papers published recently revealed that mammals diversified before the mass dinosaur extinction; uncovered a genetic explanation for why a famous sled dog from the 1920s named Balto was able to survive the harsh landscape of Alaska; discovered human-specific changes to genome organization; used machine learning to identify regions of the genome associated with brain size; described the evolution of regulatory sequences in the human genome; focused on sequences of DNA that move around the genome; discovered that species with smaller populations historically are at higher risk of extinction today; and compared genes between nearly 500 species of mammals.

 Sacha Vignieri, Zoonomia, Science (2023). DOI: 10.1126/science.adi1599. www.science.org/doi/10.1126/science.adi1599

Aryn P. Wilder et al, The contribution of historical processes to contemporary extinction risk in placental mammals, Science (2023). DOI: 10.1126/science.abn5856. www.science.org/doi/10.1126/science.abn5856

 Katherine L. Moon et al, Comparative genomics of Balto, a famous historic dog, captures lost diversity of 1920s sled dogs, Science (2023). DOI: 10.1126/science.abn5887. www.science.org/doi/10.1126/science.abn5887

Part 3

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Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 11:11am

The researchers found that at least 10% of the human genome is highly conserved across species, with many of these regions occurring outside of protein-coding genes. More than 4,500 elements are almost perfectly conserved across more than 98% of the species studied

Most of the conserved regions—which have changed more slowly than random fluctuations in the genome—are involved in embryonic development and regulation of RNA expression. Regions that changed more frequently shaped an animal's interaction with its environment, such as through immune responses or the development of its skin.

The researchers also pinpointed parts of the genome linked to a few exceptional traits in the mammalian world, such as extraordinary brain size, superior sense of smell, and the ability to hibernate during the winter.

With an eye toward preserving biodiversity, the researchers found that mammals with fewer genetic changes at conserved sites in the genome were at greater risk for extinction.

They used the mammalian genomes to study human traits and diseases. They focused on some of the most conserved single-letter genomic regions uncovered in the first paper and compared them to genetic variants that scientists have previously linked to diseases such as cancer using other methods.

The team found that their annotations of the genome based on evolutionary conservation revealed more connections between genetic variants and their function than the other methods. They also identified mutations that are likely causal in both rare and common diseases including cancer, and showed that using conservation in disease studies could make it easier to find genetic changes that increase risk of disease.

Part 2

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 11:08am

What makes the human genome unique?

Over the past 100 million years, mammals have adapted to nearly every environment on Earth.

Scientists with the Zoonomia Project have been cataloging the diversity in mammalian genomes by comparing DNA sequences from 240 species that exist today, from the aardvark and the African savanna elephant to the yellow-spotted rock hyrax and the zebu.

This week, in several papers in a special issue of Science, the Zoonomia team has demonstrated how comparative genomics can not only shed light on how certain species achieve extraordinary feats, but also help scientists better understand the parts of our genome that are functional and how they might influence health and disease.

In the new studies, the researchers identified regions of the genomes, sometimes just single letters of DNA, that are most conserved, or unchanged, across mammalian species and millions of years of evolution—regions that are likely biologically important. They also found part of the genetic basis for uncommon mammalian traits such as the ability to hibernate or sniff out faint scents from miles away. And they pinpointed species that may be particularly susceptible to extinction, as well as genetic variants that are more likely to play causal roles in rare and common human diseases.

The findings come from analyses of DNA samples collected by more than 50 different institutions worldwide which provided many genomes from species that are threatened or endangered.

Part 1

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 9:48am

Scientists slow aging by engineering longevity in cells

Human lifespan is related to the aging of our individual cells. Three years ago a group of  researchers deciphered essential mechanisms behind the aging process. After identifying two distinct directions that cells follow during aging, the researchers genetically manipulated these processes to extend the lifespan of cells.

As described in a new article published April 27, 2023, in Science, the team has now extended this research using synthetic biology to engineer a solution that keeps cells from reaching their normal levels of deterioration associated with aging.

Cells, including those of yeast, plants, animals and humans, all contain gene regulatory circuits that are responsible for many physiological functions, including aging. These gene circuits can operate like our home electric circuits that control devices like appliances and automobiles.

However, the researchers  uncovered that, under the control of a central gene regulatory circuit, cells don't necessarily age the same way. Imagine a car that ages either as the engine deteriorates or as the transmission wears out, but not both at the same time. They envisioned a "smart aging process" that extends cellular longevity by cycling deterioration from one aging mechanism to another.

In the new study, the researchers genetically rewired the circuit that controls cell aging. From its normal role functioning like a toggle switch, they engineered a negative feedback loop to stall the aging process. The rewired circuit operates as a clock-like device, called a gene oscillator, that drives the cell to periodically switch between two detrimental "aged" states, avoiding prolonged commitment to either, and thereby slowing the cell's degeneration.

These advances resulted in a dramatically extended cellular lifespan, setting a new record for life extension through genetic and chemical interventions.

The researchers in this study first used computer simulations of how the core aging circuit operates. This helped them design and test ideas before building or modifying the circuit in the cell. This approach has advantages in saving time and resources to identify effective pro-longevity strategies, compared to more traditional genetic strategies.

This is the first time computationally guided synthetic biology and engineering principles were used to rationally redesign gene circuits and reprogram the aging process to effectively promote longevity.

Zhen Zhou et al, Engineering longevity—Design of a synthetic gene oscillator to slow cellular aging, Science (2023). DOI: 10.1126/science.add7631. www.science.org/doi/10.1126/science.add7631

Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 9:40am

Newly observed effect makes atoms transparent to certain frequencies of light

A newly discovered phenomenon dubbed "collectively induced transparency" (CIT) causes groups of atoms to abruptly stop reflecting light at specific frequencies.

CIT was discovered by confining ytterbium atoms inside an optical cavity —essentially, a tiny box for light—and blasting them with a laser. Although the laser's light will bounce off the atoms up to a point, as the frequency of the light is adjusted, a transparency window appears in which the light simply passes through the cavity unimpeded.

An analysis of the transparency window points to it being the result of interactions in the cavity between groups of atoms and light. This phenomenon is akin to destructive interference, in which waves from two or more sources can cancel one another out. The groups of atoms continually absorb and re-emit light, which generally results in the reflection of the laser's light. However, at the CIT frequency, there is a balance created by the re-emitted light from each of the atoms in a group, resulting in a drop in reflection.

An ensemble of atoms strongly coupled to the same optical field can lead to unexpected results.

Through conventional quantum optics measurement techniques, researchers found that their system had reached an unexplored regime, revealing new physics.

Besides the transparency phenomenon, the researchers also observed that the collection of atoms can absorb and emit light from the laser either much faster or much slower compared to a single atom depending on the intensity of the laser. These processes, called superradiance and subradiance, and their underlying physics are still not understood properly because of the large number of interacting quantum particles.

 Mi Lei et al, Many-body cavity quantum electrodynamics with driven inhomogeneous emitters, Nature (2023). DOI: 10.1038/s41586-023-05884-1

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