Comment

Comment by Dr. Krishna Kumari Challa on March 8, 2022 at 9:43am

For the Earth's lower mantle, this changeover is relevant because some of the sediments on the seafloor, in which material from dead living creatures is deposited, enter the mantle through plate tectonics. Along the subduction zones, these sediments—along with the underlying oceanic crust—are transported to great depths. In this way, the carbon that was stored as organic material in the sediments also reaches the Earth's mantle. There the sediments mix with other rock material from the Earth's mantle and after a certain time, estimated to at least 200–300 million years, rise to the Earth's surface again in other places—for example in the form of kimberlite magmas.

It is remarkable that changes in marine sediments leave such profound traces, because overall, only small amounts of sediment are transported into the depths of the mantle along a subduction zone. This confirms that the subducted rock material in the Earth's mantle is not distributed homogeneously, but moves along specific trajectories.

In addition to carbon, the researchers also examined the isotopic composition of other chemical elements. For example, the two elements strontium and hafnium showed a similar pattern to carbon.

Andrea Giuliani et al, Perturbation of the deep-Earth carbon cycle in response to the Cambrian Explosion, Science Advances (2022). DOI: 10.1126/sciadv.abj1325

https://phys.org/news/2022-03-life-earth-deep-mantle.html?utm_sourc...

Part 2

Comment by Dr. Krishna Kumari Challa on March 8, 2022 at 9:41am

Traces of life in the Earth's deep mantle

The rapid development of fauna 540 million years ago has permanently changed the Earth—deep into its lower mantle. A team of researchers now found traces of this development in rocks from this zone.

It is easy to see that the processes in the Earth's interior influence what happens on the surface. For example, volcanoes unearth magmatic rocks and emit gases into the atmosphere, and thus influence the biogeochemical cycles on our planet.

What is less obvious, however, is that the reverse is also true: what happens on the Earth's surface effect the Earth's interior—even down to great depths. This is the conclusion reached by an international group of researchers  in a new study published in the journal Science Advances. According to this study, the development of life on our planet affects parts of Earth's lower mantle.

In their study, the researchers examined rare diamond-bearing volcanic rocks called kimberlites from different epochs of the Earth's history. These special rocks are messengers from the lowest regions of the Earth's mantle. Scientists measured the isotopic composition of carbon in about 150 samples of these special rocks. They found that the composition of younger kimberlites, which are less than 250 million years old, varies considerably from that of older rocks. In many of the younger samples, the composition of the carbon isotopes is outside the range that would be expected for rocks from the mantle.

The researchers see a decisive trigger for this change in composition of younger kimberlites in the Cambrian Explosion. This relatively short phase—geologically speaking—took place over a period of few tens of million years at the beginning of the Cambrian Epoch, about 540 million years ago. During this drastic transition, almost all of today's existing animal tribes appeared on Earth for the first time. The enormous increase in life forms in the oceans decisively changed what was happening on the Earth's surface. And this in turn affected the composition of sediments at the bottom of the ocean.

Part 1

Comment by Dr. Krishna Kumari Challa on March 8, 2022 at 9:31am

Tiny 'skyscrapers' help bacteria convert sunlight into electricity

Researchers have made tiny 'skyscrapers' for communities of bacteria, helping them to generate electricity from just sunlight and water.

The researchers used 3D printing to create grids of high-rise 'nano-housing' where sun-loving bacteria can grow quickly. The researchers were then able to extract the bacteria's waste electrons, left over from photosynthesis, which could be used to power small electronics.

Other research teams have extracted energy from photosynthetic bacteria, but now the researchers have found that providing them with the right kind of home increases the amount of energy they can extract by over an order of magnitude. The approach is competitive against traditional methods of renewable bioenergy generation and has already reached solar conversion efficiencies that can outcompete many current methods of biofuel generation.

Their results, reported in the journal Nature Materials, open new avenues in bioenergy generation and suggest that 'biohybrid' sources of solar energy could be an important component in the zero-carbon energy mix.

Jenny Zhang, 3D-printed hierarchical pillar array electrodes for high-performance semi-artificial photosynthesis, Nature Materials (2022). DOI: 10.1038/s41563-022-01205-5. www.nature.com/articles/s41563-022-01205-5

https://techxplore.com/news/2022-03-tiny-skyscrapers-bacteria-sunli...

Comment by Dr. Krishna Kumari Challa on March 7, 2022 at 9:08am

It appears that this pocket, specifically built to recognize these fatty acids, gives SARS-CoV-2 an advantage inside the body of infected people, allowing it to multiply so fast. This could explain why it is there, in all variants, including Omicron. Intriguingly, the same feature also provides us with a unique opportunity to defeat the virus, exactly because it is so conserved—with a tailormade antiviral molecule that blocks the pocket.

Kapil Gupta et al, Structural insights in cell-type specific evolution of intra-host diversity by SARS-CoV-2, Nature Communications (2022). DOI: 10.1038/s41467-021-27881-6

Oskar Staufer et al, Synthetic virions reveal fatty acid-coupled adaptive immunogenicity of SARS-CoV-2 spike glycoprotein, Nature Communications (2022). DOI: 10.1038/s41467-022-28446-x

https://medicalxpress.com/news/2022-03-sars-cov-infected-individual...

Part 2

Comment by Dr. Krishna Kumari Challa on March 7, 2022 at 9:07am

SARS-CoV-2-infected individuals could have different variants hidden in different parts of the body

People suffering from COVID-19 could have several different SARS-CoV-2 variants hidden away from the immune system in different parts of the body, finds new research published in Nature Communications by an international research team. The study's authors say that this may make complete clearance of the virus from the body of an infected person, by their own antibodies, or by therapeutic antibody treatments, much more difficult.

In new research, comprising two studies published in parallel in Nature Communications, an international team led by Professor Imre Berger at the University of Bristol and Professor Joachim Spatz at the Max Planck Institute for Medical Research in Heidelberg , both Directors of the Max Planck Bristol Centre of Minimal Biology, show how the virus can evolve distinctly in different cell types, and adapt its immunity, in the same infected host.

The team sought to investigate the function of a tailor-made pocket in the SARS-CoV-2 spike protein in the infection cycle of the virus. The pocket, discovered by the Bristol team in an earlier breakthrough, played an essential role in viral infectivity.

These results showed that one can have several different virus variants in one's body. Some of these variants may use kidney or spleen cells as their niche to hide, while the body is busy defending against the dominant virus type. This could make it difficult for the infected patients to get rid of SARS-CoV-2 entirely.

Using these artificial virions, they were able to study the exact mechanism of the pocket in viral infection. They demonstrated that upon binding of a fatty acid, the spike protein decorating the virions changed their shape. This switching 'shape' mechanism effectively cloaks the virus from the immune system. "By 'ducking down' of the spike protein upon binding of inflammatory fatty acids, the virus becomes less visible to the immune system. This could be a mechanism to avoid detection by the host and a strong immune response for a longer period of time and increase total infection efficiency.

Part 1

Comment by Dr. Krishna Kumari Challa on March 5, 2022 at 11:52am

Progress through research
Through earlier studies, Shulman's lab team had identified the inhibition of the mitochondrial-associated enzyme glycerol phosphate dehydrogenase, which converts glycerol to glucose, as a potential mechanism for metformin action. Now, in the current study, they were able to show through another series of experiments that metformin, as well as the related drugs phenformin and galegine, did in fact inhibit glycerol conversion to glucose both in vitro and in vivo and that they did so through an indirect mechanism by inhibiting complex IV activity.

"Taken together these studies show that metformin does not lower blood glucose by inhibition of complex I activity, but instead it reduces blood glucose through inhibition of complex IV activity which in turn leads to inhibition of glycerol phosphate dehydrogenase activity and reductions in glycerol conversion to glucose" says Shulman.

Why it matters to know
It is not uncommon for drugs to be approved for clinical use despite researchers not understanding how they work, if they are shown to be safe and effective. But Shulman says research on poorly understood medications like metformin allows scientists to develop more beneficial treatments. Taking metformin, for example, can lead to unpleasant side effects such as gastrointestinal distress, leading many patients to stop taking it. Shulman hopes his team's research can lead to the development of diabetes drugs with the safe efficacy of metformin but higher tolerability.

https://medicine.yale.edu/news-article/how-a-widely-used-diabetes-m...

https://researchnews.cc/news/11938/How-a-widely-used-diabetes-medic...

Part 2

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Comment by Dr. Krishna Kumari Challa on March 5, 2022 at 11:51am

How a widely used diabetes medicine metformin

actually works

Physicians have used the drug metformin to treat type 2 diabetes for more than half a century, but despite its prevalence, researchers have lacked a clear understanding of how it works. Now, Yale researchers have elucidated the mechanism behind metformin and related type 2 diabetes drugs, and debunked a previously held theory on how they work. The team, including senior author Gerald Shulman, MD, Ph.D., George R. Cowgill Professor of Medicine (Endocrinology) and professor of cellular and molecular physiology, and first author Traci LaMoia, a graduate student in Shulman's lab, published their findings in PNAS on March 1.

"Metformin is the most commonly used drug to treat diabetes," says Shulman. "It's important to understand how it works so we can potentially develop even better drugs to treat type 2 diabetes."

Studies in humans have shown that metformin inhibits the process of gluconeogenesis, which is how the liver makes glucose from non-glucose precursors such as amino acids and lactate. How it accomplishes this, however, has been a mystery.

Mitochondria in cells generate energy through the electron transport chain, which consists of four protein complexes that release energy through a series of reactions. Most scientists previously believed that metformin works by inhibiting complex I, the first and largest of the mitochondrial complexes that creates the hydrogen ion gradient. However, Shulman's group has previously demonstrated that metformin only inhibits complex I at much higher pharmacological concentrations than what is typically prescribed.

To further test this hypothesis, the team performed a series of experiments both in liver slices and in mice. Using a complex I inhibitor known as piercidin A, they found that this mechanism failed to reduce liver gluconeogenesis. "Using a very specific inhibitor of complex I, we show that complex I inhibition doesn't reduce blood glucose in both in vitro and in vivo studies," says Shulman.

Part 1

Comment by Dr. Krishna Kumari Challa on March 5, 2022 at 11:37am

Mucus could explain why SARS-CoV-2 doesn't spread easily from surfaces

Early in the pandemic, many people fastidiously disinfected surfaces because laboratory studies predicted that SARS-CoV-2 could be easily transmitted in this way. Now, researchers reporting in ACS Central Science have found a possible explanation for why the predictions didn’t pan out: Sugar-decorated proteins in mucus could bind to the coronavirus on surfaces, keeping it from infecting cells. The findings could also hint at why some people are more vulnerable to COVID-19 than others.

Although experiments have shown that coronaviruses can persist on surfaces for days or weeks, it is now apparent that SARS-CoV-2 is much more likely to infect people through airborne droplets carrying the virus. The surface studies typically used viruses suspended in buffers or growth media, whereas in the real world, SARS-CoV-2 is coated in mucus when someone coughs or sneezes. With this in mind,  researchers wondered if mucus components could explain the discrepancy between the lab predictions and reality. In addition to water, salts, lipids, DNA and other proteins, mucus contains proteins called mucins, which are heavily modified with sugar molecules known as glycans. To infect cells, the SARS-CoV-2 spike protein binds glycan molecules with sialic acid at their ends on the cell surface. So, the researchers wondered if the coronavirus also recognizes sialic acid-containing glycans in mucins. If the spike protein is already bound to glycans in mucus, perhaps it couldn’t bind to the ones on cells, they reasoned.

For safety reasons, the researchers chose to study a human coronavirus called OC43, which evolved relatively recently from a cow coronavirus and causes mostly mild respiratory infections. The team deposited droplets of the virus in buffer or growth medium supplemented with 0.1–5% mucins, which corresponds to the concentration range of mucins found in nasal mucus and saliva, onto a plastic surface and let the drops dry. Then, they rehydrated the viral residue and measured its ability to infect cells. In comparison to the buffer or growth medium alone, the solutions supplemented with mucins were dramatically less infectious. The team also tested steel, glass and surgical mask surfaces, finding similar results.

The researchers showed that, as the droplets dried, mucins moved to the edge and concentrated there in a coffee-ring effect, bringing the virus with them. This brought mucins and virus particles close together, where they could more easily interact. Cutting off sialic acid glycans from mucins with an enzyme eliminated viral binding and destroyed the glycoproteins’ protective effect. Because SARS-CoV-2, like OC43, binds to sialic acid glycans on cell surfaces, mucins would also likely reduce its infectivity, the researchers suspect. The levels and types of sugar molecules on mucins can vary with diet and certain diseases, which could possibly explain the vulnerability of certain people to COVID-19, they say.

Casia L. Wardzala, Amanda M. Wood, David M. Belnap, Jessica R. Kramer. Mucins Inhibit Coronavirus Infection in a Glycan-Dependent Manner. ACS Central Science, 2022; DOI: 10.1021/acscentsci.1c01369

https://researchnews.cc/news/11925/Mucus-could-explain-why-SARS-CoV...

Comment by Dr. Krishna Kumari Challa on March 5, 2022 at 10:00am

Seaspiracy

Comment by Dr. Krishna Kumari Challa on March 4, 2022 at 11:56am

p53: meet the anticancer protein

The tumour-suppressing protein p53 acts as the guardian of the genome by providing important protection against cancer — when it is active, that is. Many malignant cells exhibit p53 dysfunction, and several clinical trials of agents intended to restore p53 to working order are now underway.

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