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Comment by Dr. Krishna Kumari Challa on December 8, 2023 at 2:03pm

Study reveals genes that set humans apart from other primates in cognitive ability

An international team of researchers has uncovered over 100 genes that are common to primate brains but have undergone evolutionary divergence only in humans – and which could be a source of our unique cognitive ability.

They found the genes are expressed differently in the brains of humans compared to four of our relatives – chimpanzees, gorillas, macaques and marmosets.

The findings, published in Nature Ecology & Evolution, suggest that reduced selective pressure, or tolerance to loss-of-function mutations, may have allowed the genes to take on higher-level cognitive capacity. The study is part of the Human Cell Atlas, a global initiative to map all human cells to better understand health and disease.
This research contributes to our understanding of differences in the brain between humans and other primates at the cellular level, but it has also resulted in a database that can be used to further characterize genetic similarities and differences across primates.

In all, the team found 139 genes that are common across the primate groups but highly divergent in their expression in human brains. These genes displayed a stronger ability to withstand mutations without impacting their function, suggesting they may have evolved under more relaxed selective pressure.

The genes that have diverged in humans must be tolerant to change. This manifests as tolerance to loss-of-function mutations, and seems to allow for rapid evolutionary change in the human brain.

Our higher cognitive function may have resulted from the adaptive evolution of human brain cells to a multitude of less threatening mutations over time. It’s also worth noting that around a quarter of the human-divergent genes identified in the study are associated with various brain disorders.

The divergent genes the researchers identified are found in 57 brain cell types, grouped by inhibitory neurons, excitatory neurons and non-neurons. A quarter of the genes were only expressed differently in neuronal cells, also known as grey matter, and half were only expressed differently in glial cells, which are white matter.

Grey matter in the brain consists of neurons, while white matter consists of other cell types, including those responsible for vasculature and immune function.

 Hamsini Suresh et al, Comparative single-cell transcriptomic analysis of primate brains highlights human-specific regulatory evolution, Nature Ecology & Evolution (2023). DOI: 10.1038/s41559-023-02186-7

Comment by Dr. Krishna Kumari Challa on December 8, 2023 at 1:56pm

Scientists create 'cloaked' donor cell, tissue grafts that escape immune system rejection

Immune rejection poses a major challenge in donor cell therapy. Transplant and cell therapy patients are required to take immunosuppressive drugs – sometimes for the rest of their lives – to prevent their bodies from rejecting the transplant. The extended use of these drugs can lead to serious health issues, including recurring infections and an elevated cancer risk.

Scientists worldwide have been exploring various solutions, including creating therapeutic cells from the patient’s own cells or encapsulating donor cells in inorganic material for protection.

But these methods face challenges such as high costs, long preparation times and foreign body immune response, complicating their widespread and cost-effective application.

Researchers now have developed a technology that may one day eliminate the need for immunosuppressive drugs in transplant patients.
Through genetic modification of donor cells, the researchers successfully created transplants that persisted long-term in pre-clinical testing without the need for immune suppression.
The findings raise hope that a similar strategy could be employed in human patients, potentially making transplantation safer and more widely available.

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Stem cells have the unique ability to divide indefinitely and give rise to specialized cells that form our organs. They make an ideal source for cell therapies as large numbers of cells can be obtained and converted into desired cell types to replace those lost to disease or injury.

But there are major safety concerns: in addition to addressing immune-matching, scientists must ensure that no unwanted dividing cells remain in the transplant that could cause cancer in the future.

Researchers  selected eight key genes that regulate how the immune system responds to threats, including foreign cells. Forced overexpression of these genes in mouse embryonic stem cells prevented the immune system from recognizing them as foreign.

The modification effectively created an immune cloak around the cells following their injection under the skin of genetically unmatched hosts.

This study demonstrates the combined potential of FailSafe and immune cloaking for the creation of a universal source of cells that could be applied to a multitude of diseases.

Uncloaked cells are typically rejected within 10 days of transplantation. In contrast, the cloaked cells persisted for more than nine months at the endpoint of the experiment. This is the first time that  scientists have been able to achieve this length of time without rejection in a fully functional immune system.

In another key finding, the researchers showed that unmodified cells can escape rejection when embedded into the tissue created by the cloaked donor cells below the skin surface. The protection extended to cells from another species, as shown by the ability of unmodified human cells to survive within a cloaked mouse graft.

This suggests that modified cells also act as an immune-privileged implantation site for unmodified cells, with implications for interspecies transplants. Researchers at other institutions are exploring the potential of pigs as donors because their organs are very similar in size and function to humans.

https://www.nature.com/articles/s41551-023-01133-y

Comment by Dr. Krishna Kumari Challa on December 8, 2023 at 1:34pm

Physicists 'entangle' individual molecules for the first time, hastening possibilities for quantum computing

For the first time, a team of  physicists have been able to link together individual molecules into special states that are quantum mechanically "entangled." In these bizarre states, the molecules remain correlated with each other—and can interact simultaneously—even if they are miles apart, or indeed, even if they occupy opposite ends of the universe. This research was recently published in the journal Science.

This is a breakthrough in the world of molecules because of the fundamental importance of quantum entanglement. And it is also a breakthrough for practical applications because entangled molecules can be the building blocks for many future applications.

These include, for example, quantum computers that can solve certain problems much faster than conventional computers, quantum simulators that can model complex materials whose behaviors are difficult to model, and quantum sensors that can measure faster than their traditional counterparts.

To entangle the molecules, they had to make the molecule interact. By using a series of microwave pulses, they were able to make individual molecules interact with one another in a coherent fashion.

By allowing the interaction to proceed for a precise amount of time, they were able to implement a two-qubit gate that entangled two molecules. This is significant because such an entangling two-qubit gate is a building block for both universal digital quantum computing and for simulation of complex materials.

Connor M. Holland et al, On-demand entanglement of molecules in a reconfigurable optical tweezer array, Science (2023). DOI: 10.1126/science.adf4272. www.science.org/doi/10.1126/science.adf4272

Yicheng Bao et al, Dipolar spin-exchange and entanglement between molecules in an optical tweezer array, Science (2023). DOI: 10.1126/science.adf8999. www.science.org/doi/10.1126/science.adf8999

Augusto Smerzi et al, Entanglement with tweezed molecules, Science (2023). DOI: 10.1126/science.adl4179. www.science.org/doi/10.1126/science.adl4179

Comment by Dr. Krishna Kumari Challa on December 8, 2023 at 10:41am

Those patterns signaled that some elements listed near the middle of the periodic table—such as silver and rhodium—were likely the remnants of heavy element fission. The team was able to determine that the r-process can produce atoms with an atomic mass of at least 260 before they fission.

That 260 is interesting because we haven't previously detected anything that heavy in space or naturally on Earth, even in nuclear weapon tests.

 Ian U. Roederer et al, Element abundance patterns in stars indicate fission of nuclei heavier than uranium, Science (2023). DOI: 10.1126/science.adf1341. www.science.org/doi/10.1126/science.adf1341

Part 2

Comment by Dr. Krishna Kumari Challa on December 8, 2023 at 10:40am

Ancient stars made extraordinarily heavy elements, researchers find

How heavy can an element be? An international team of researchers has found that ancient stars were capable of producing elements with atomic masses greater than 260, heavier than any element on the periodic table found naturally on Earth. The finding deepens our understanding of element formation in stars.

We are, literally, made of star stuff. Stars are element factories, where elements constantly fuse or break apart to create other lighter or heavier elements. When we refer to light or heavy elements, we're talking about their atomic mass. Broadly speaking, atomic mass is based on the number of protons and neutrons in the nucleus of one atom of that element.
The heaviest elements are only known to be created in neutron stars via the rapid neutron capture process, or r-process. Picture a single atomic nucleus floating in a soup of neutrons. Suddenly, a bunch of those neutrons get stuck to the nucleus in a very short time period—usually in less than one second—then undergo some internal neutron-to-proton changes, and voila! A heavy element, such as gold, platinum or uranium, forms.

The heaviest elements are unstable or radioactive, meaning they decay over time. One way that they do this is by splitting, a process called fission.

The r-process is necessary if you want to make elements that are heavier than, say, lead and bismuth.
You have to add many neutrons very quickly, but the catch is that you need a lot of energy and a lot of neutrons to do so. And the best place to find both are at the birth or death of a neutron star, or when neutron stars collide and produce the raw ingredients for the process.
The team took a fresh look at the amounts of heavy elements in 42 well-studied stars in the Milky Way. The stars were known to have heavy elements formed by the r-process in earlier generations of stars. By taking a broader view of the amounts of each heavy element found in these stars collectively, rather than individually as is more common, they identified previously unrecognized patterns.
Part 1

Comment by Dr. Krishna Kumari Challa on December 7, 2023 at 11:43am

Warfare ruins the environment—and not just on the front lines

On the morning of December 6, 1917, a French cargo ship called SS Mont-Blanc collided with a Norwegian vessel in the harbor of Halifax in Nova Scotia, Canada. The SS Mont-Blanc, which was laden with 3,000 tons of high explosives destined for the battlefields of the first world war, caught fire and exploded. The resulting blast released an amount of energy equivalent to roughly 2.9 kilotons of TNT, destroying a large part of the city. Although it was far from the front lines, this explosion left a lasting imprint on Halifax in a way that many regions experience environmental change as a result of war. The attention of the media is often drawn to the destructive explosions caused by bombs, drones or missiles. And the devastation we have witnessed in cities like Aleppo, Mosul, Mariupol and now Gaza certainly serve as stark reminders of the horrific impacts of military action. However, research is increasingly uncovering broader and longer-term consequences of war that extend well beyond the battlefield. Armed conflicts leave a lasting trail of environmental damage, posing challenges for restoration after the hostilities have eased.

https://theconversation.com/warfare-ruins-the-environment-and-not-j...

Comment by Dr. Krishna Kumari Challa on December 7, 2023 at 11:40am

Planet tipping points pose 'unprecedented' threat to humanity: report

Humanity faces an "unprecedented" risk from tipping points that could unleash a domino effect of irreversible catastrophes across the planet, researchers warned this week.

The most comprehensive assessment ever conducted of Earth's invisible tripwires was released as leaders meet for UN climate talks in Dubai with 2023 set to smash all heat records. While many of the 26 tipping points laid out in the report—such as melting ice sheets—are linked to global warming, other human activities like razing swathes of the Amazon rainforest could also push Earth's ecosystems to the brink. Five of these are showing signs of tipping—from melting ice sheets threatening catastrophic sea level rise, to mass die-off of tropical coral reefs—the report warned. Some may have already begun to irrecoverably transform. Once the world crosses the threshold for just one tipping point, dealing with the immediate humanitarian disaster could distract attention away from stopping the others, creating a "vicious cycle" of mass hunger, displacement and conflict, the report warned.

The risks for humanity in crossing tipping points into these unexplored states is dire, and the impact to human lives potentially horrific.

Source: News agencies

Comment by Dr. Krishna Kumari Challa on December 7, 2023 at 11:32am

Study finds climate change can cause methane to be released from the deep ocean

New research has shown that fire-ice—frozen methane which is trapped as a solid under our oceans—is vulnerable to melting due to climate change and could be released into the sea.

An international team of researchers found that as frozen methane and ice melts, methane—a potent greenhouse gas—is released and moves from the deepest parts of the continental slope to the edge of the underwater shelf. They even discovered a pocket that had moved 25 miles (40 kilometers). Publishing in the journal Nature Geoscience, the researchers say this means that much more methane could potentially be vulnerable and released into the atmosphere as a result of climate warming.

Methane hydrate, also known as fire-ice, is an ice-like structure found buried in the ocean floor that contains methane. Vast amounts of methane are stored as marine methane under oceans. It thaws when the oceans warm, releasing methane into oceans and the atmosphere—known as dissociated methane—contributing to global warming.

The scientists used advanced three-dimensional seismic imaging techniques to examine the portion of the hydrate that dissociated during climatic warming off the coast of Mauritania in Northwest Africa. They identified a specific case where dissociated methane migrated over 40 kilometers and was released through a field of underwater depressions, known as pockmarks, during past warm periods.

Long-distance migration and venting of methane after marine hydrate dissociation, Nature Geoscience (2023). DOI: 10.1038/s41561-023-01333-w. www.nature.com/articles/s41561-023-01333-w

Comment by Dr. Krishna Kumari Challa on December 7, 2023 at 10:44am

Researchers show that an influx of water and salts propel immune cells through the body

Researchers have shown that an influx of water and ions into immune cells allows them to migrate to where they're needed in the body.

Our bodies respond to illness by sending out chemical signals called chemokines, which tell immune cells called T cells where to go to fight the infection. This process had already been associated with a protein called WNK1, which activates channels on the cell surface,  allowing ions (salts like sodium or potassium) to move into cells. Until now, it was not clear why ion influx was needed for T cells to move.

Through a study published in Nature Communications, the researchers imaged mouse T cells and observed that, following a chemokine signal, WNK1 is activated at the front of the cells, called the "leading edge." The team showed that the activation of WNK1 opens channels on the leading edge, resulting in an influx of water and ions. They propose that this flow of water causes the cells to swell on the front side, creating space for the 'actin cytoskeleton'—the scaffolding inside the cell that holds its structure—to grow into. This propels the whole cell forward and the process repeats again. The researchers used gene editing to stop mice producing WNK1, or an inhibitor to prevent WNK1's activity, observing that the T cells in these mice slowed down or stopped moving completely. Importantly, they found that they could make up for the loss of WNK1 and make the cells speed up by dropping them into a watery solution, which causes the cells to take up water and swell. This shows that the uptake of water, controlled by the WNK1 protein is key for the cells to migrate.

The researchers think that the mechanism they've discovered could be involved in lots of different cell types beyond immune cells.

Leonard L. de Boer et al, T cell migration requires ion and water influx to regulate actin polymerization, Nature Communications (2023). DOI: 10.1038/s41467-023-43423-8

Comment by Dr. Krishna Kumari Challa on December 7, 2023 at 10:39am

Plant Hormone That Can Boost Plant Growth By 30%

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