Comment

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 10:53am

How to image atoms

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 9:58am

Some birds sing the same song for hundreds of thousands of years

Many of the birds that awaken us each morning learn their melodious songs the same way that humans learn a dialect—from parents and neighbours.

But to most biologists, learning songs through mimicry is an uncertain and error-prone process, resulting in slow but inevitable change in song over the years.

A new study by biologists , however, documents songs in East African sunbirds that have remained nearly unchanged for more than 500,000 years, and perhaps for as long as 1 million years, making the songs nearly indistinguishable from those of relatives from which they've long been separated.

The amazingly static nature of their songs may be due to a lack of change in these birds' environments, which are stable mountain forests—so-called sky islands—isolated from other sky island populations of the same or similar species for tens of thousands to millions of years. The coloration of the birds' feathers has changed little, as well, making their plumage nearly indistinguishable from each other, even though some are separate, but closely related, species.

Jay P. McEntee et al, Punctuated evolution in the learned songs of African sunbirds, Proceedings of the Royal Society B: Biological Sciences (2021). DOI: 10.1098/rspb.2021.2062

https://phys.org/news/2022-01-birds-song-hundreds-thousands-years.h...

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 9:46am

Lost birds and mammals spell doom for some plants

In one of the first studies of its kind, researchers have gauged how biodiversity loss of birds and mammals will impact plants' chances of adapting to human-induced climate warming.

More than half of plant species rely on animals to disperse their seeds. In a study  researchers showed the ability of animal-dispersed plants to keep pace with climate change has been reduced by 60% due to the loss of mammals and birds that help such plants adapt to environmental change.

As climate changes, many plant species must move to a more suitable environment. Plants that rely on seed dispersers can face extinction if there are too few animals to move their seeds far enough to keep pace with changing conditions.

If there are no animals available to eat their fruits or carry away their nuts, animal-dispersed plants aren't moving very far. And many plants people rely on, both economically and ecologically, are reliant on seed-dispersing birds and mammals.

The study showed seed-dispersal losses were especially severe in temperate regions across North America, Europe, South America and Australia. If endangered species go extinct, tropical regions in South America, Africa and Southeast Asia would be most affected.

Evan C. Fricke, The effects of defaunation on plants' capacity to track climate change, Science (2022). DOI: 10.1126/science.abk3510. www.science.org/doi/10.1126/science.abk3510

https://phys.org/news/2022-01-lost-birds-mammals-doom.html?utm_sour...

Comment by Dr. Krishna Kumari Challa on January 14, 2022 at 9:37am

Researchers propose new explanation for Moon's half-century magnetic mystery

Rocks returned to Earth during NASA's Apollo program from 1968 to 1972 have provided volumes of information about the Moon's history, but they've also been the source of an enduring mystery. Analysis of the rocks revealed that some seemed to have formed in the presence of a strong magnetic field—one that rivaled Earth's in strength. But it wasn't clear how a Moon-sized body could have generated a magnetic field that strong.

Now, new research proposes a new explanation for the Moon's magnetic mystery. The study, published in Nature Astronomy, shows that giant rock formations sinking through the Moon's mantle could have produced the kind of interior convection that generates strong magnetic fields. The processes could have produced intermittently strong magnetic fields for the first billion years of the Moon's history, the researchers say.

The Moon lacks a magnetic field today, and models of its core suggest that it was probably too small and lacked the convective force to have ever produced a continuously strong magnetic field. In order for a core to have a strong convective churn, it needs to dissipate a lot of heat. In the case of the early Moon, researchers say, the mantle surrounding the core wasn't much cooler than the core itself. Because the core's heat didn't have anywhere to go, there wasn't much convection in the core. But this new study shows how sinking rocks could have provided intermittent convective boosts.

The story of these sinking stones starts a few million years after the Moon's formation. Very early in its history, the Moon is thought to have been covered by an ocean of molten rock. As the vast magma ocean began to cool and solidify, minerals like olivine and pyroxene that were denser than the liquid magma sank to the bottom, while less dense minerals like anorthosite floated to form the crust. The remaining liquid magma was rich in titanium as well as heat-producing elements like thorium, uranium and potassium, so it took a bit longer to solidify. When this titanium layer finally crystallized just beneath the crust, it was denser than the earlier-solidifying minerals below it. Over time, the titanium formations sank through the less-dense mantle rock underneath, a process known as gravitational overturn.

There could have been as many as 100 of these downwelling events over the Moon's first billion years of existence, the researchers say, and each one could have produced a strong magnetic field lasting a century or so.

Alexander Evans, An episodic high-intensity lunar core dynamo, Nature Astronomy (2022). DOI: 10.1038/s41550-021-01574-y. www.nature.com/articles/s41550-021-01574-y

https://phys.org/news/2022-01-explanation-moon-half-century-magneti...

Comment by Dr. Krishna Kumari Challa on January 13, 2022 at 12:56pm

Antibody Cocktail Therapy Explained

Comment by Dr. Krishna Kumari Challa on January 13, 2022 at 12:28pm

The scientists found that the way DNA was wrapped around different types of proteins was a good predictor of whether a gene would mutate or not. It means we can predict which genes are more likely to mutate than others and it gives us a good idea of what's going on.

The findings add a surprising twist to Charles Darwin's theory of evolution by natural selection because it reveals that the plant has evolved to protect its genes from mutation to ensure survival.

The plant has evolved a way to protect its most important places from mutation. This is exciting because we could even use these discoveries to think about how to protect human genes from mutation.

Knowing why some regions of the genome mutate more than others could help breeders who rely on genetic variation to develop better crops. Scientists could also use the information to better predict or develop new treatments for diseases like cancer that are caused by mutation.

Detlef Weigel, Mutation bias reflects natural selection in Arabidopsis thaliana, Nature (2022). DOI: 10.1038/s41586-021-04269-6. www.nature.com/articles/s41586-021-04269-6

https://phys.org/news/2022-01-evolutionary-theory-dna-mutations-ran...

Comment by Dr. Krishna Kumari Challa on January 13, 2022 at 12:27pm

Study challenges evolutionary theory that DNA mutations are random

A simple roadside weed may hold the key to understanding and predicting DNA mutation, according to new research.

The findings, published January 12 in the journal Nature, radically change our understanding of evolution and could one day help researchers breed better crops or even help humans fight cancer.

Mutations occur when DNA is damaged and left unrepaired, creating a new variation. The scientists wanted to know if mutation was purely random or something deeper. What they found was unexpected.

Scientists thought of mutation as basically random across the genome till now. It turns out that mutation is very non-random and it's non-random in a way that benefits the plant. It's a totally new way of thinking about mutation.

Researchers spent three years sequencing the DNA of hundreds of Arabidopsis thaliana, or thale cress, a small, flowering weed considered the "lab rat among plants" because of its relatively small genome comprising around 120 million base pairs. Humans, by comparison, have roughly 3 billion base pairs. It's a model organism for genetics. 

Researchers grew specimens in a protected lab environment, which allowed plants with defects that may not have survived in nature be able to survive in a controlled space.

Sequencing of those hundreds of Arabidopsis thaliana plants revealed more than 1 million mutations. Within those mutations a nonrandom pattern was revealed, counter to what was expected.

Instead of randomness scientists found patches of the genome with low mutation rates. In those patches, they were surprised to discover an over-representation of essential genes, such as those involved in cell growth and gene expression. 

These are the really important regions of the genome. The areas that are the most biologically important are the ones being protected from mutation.

The areas are also sensitive to the harmful effects of new mutations. DNA damage repair seems therefore to be particularly effective in these regions.

Part 1

Comment by Dr. Krishna Kumari Challa on January 12, 2022 at 5:19am

‘If it’s not on arXiv, it doesn’t exist’

On January 3, the arXiv server hit a milestone when it published its two milliont.... Since it was created in 1991 by physicist Paul Ginsparg, the repository has become indispensable for sharing research in fields such as astronomy, particle physics and mathematics. Such explosive growth is not painless: a handful of staff and volunteer moderators work to ensure that the 1,200 daily submissions meet basic quality standards. Critics worry that the full diversity of scientific thought — and of scientists themselves — is not represented among those gatekeepers. And the site has struggled with stability. “We’re an old classic car, and the rust has finally come through, and the pistons are wearing out,” says astrophysicist Steinn Sigurdsson, arXiv’s scientific director. “We are understaffed and underfunded — and have been for years.”

Comment by Dr. Krishna Kumari Challa on January 12, 2022 at 5:17am

First person receives gene-edited pig heart

A person in the United States is the first to receive a transplant of a genetically modified pig heart. Yesterday, the University of Maryland Medical Center announced that the 57-year-old patient was still doing well 3 days after the surgery. The heart came from a pig raised by Revivicor, a US firm that spun off from the UK company that helped to clone Dolly the sheep. It’s not clear exactly how the pig was gene-edited, but the company has developed pigs whose cell surfaces do not have a sugar molecule called α-1,3-galactose, or α-gal, which triggers the human immune system. The man also received an experimental drug made by Kiniksa Pharmaceuticals designed to stave off rejection.

Comment by Dr. Krishna Kumari Challa on January 11, 2022 at 8:53am

Scientists uncover new information about cellular death process, previously thought to be irreversible

A study published by researchers at the University of Illinois Chicago describes a new method for analyzing pyroptosis—the process of cell death that is usually caused by infections and results in excess inflammation in the body—and shows that process, long thought to be irreversible once initiated, can in fact be halted and controlled.

The discovery, which is reported in Nature Communications, means that scientists have a new way to study diseases that are related to malfunctioning cell death processes, like some cancers, and infections that can be complicated by out-of-control inflammation caused by the process. These infections include sepsis, for example, and acute respiratory distress syndrome, which is among the major complications of COVID-19 illness.

Pyroptosis is a series of biochemical reactions that uses gasdermin, a protein, to open large pores in the cell membrane and destabilize the cell. To understand more about this process, the researchers designed an "optogenetic" gasdermin by genetically engineering the protein to respond to light.

The researchers applied the optogenetic gasdermin tool and used florescent imaging technology to precisely activate gasdermin in cell experiments and observe the pores under various circumstances. They discovered that certain conditions, like specific concentrations of calcium ions, for example, triggered the pores to close within only tens of seconds.

This automatic response to external circumstances provides evidence that pyroptosis dynamically self-regulates.

"This showed us that this form of cell death is not a one-way ticket. The process is actually programmed with a cancel button, an off-switch.

Understanding how to control this process unlocks new avenues for drug discovery, and now we can find drugs that work for both sides—it allows us to think about tuning, either boosting or limiting, this type of cell death in diseases, where we could previously only remove this important process.

Ana Beatriz Santa Cruz Garcia et al, Gasdermin D pores are dynamically regulated by local phosphoinositide circuitry, Nature Communications (2022). DOI: 10.1038/s41467-021-27692-9

https://phys.org/news/2022-01-scientists-uncover-cellular-death-pre...

• ‹ Previous
• 1
• …
• 292
• 293
• 294
• 295
• 296
• …
• 842
• Next ›
• Page