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Comment by Dr. Krishna Kumari Challa on February 8, 2023 at 10:22am

New way climate change is fueling itself

Healthy, undisturbed soil sinks carbon, storing what's generated when plants and other living things decompose so it doesn't get released as a planet-warming greenhouse gas.

But a new study  suggests nitrogen pollution from cars and trucks and power plants might make soil release that carbon in dry places—worsening, rather than helping to fight, climate change.

In places that get more regular rain and snow, other studies have shown that adding nitrogen to soil can increase carbon storage. Nitrogen fuels plant growth, which captures carbon and draws it down into the soil. It also helps slow decomposition of whatever is in the soil.

Dryland ecosystems cover roughly 45% of land on Earth. They also store 33% of the carbon found in the top layer of soil worldwide. So if nitrogen pollution is making the carbon stored in these soils vulnerable, that definitely rings some alarm bells.

The findings offer new motivation, then, to speed the transition away from fossil fuels and cut back on nitrogen-rich fertilizer if we want to slow global warming that's already creating climate refugees due to worsening heat waves, droughts, floods and wildfires.

https://phys.org/news/2023-02-dirty-truth-climate-fueling.html?utm_...

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Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 12:38pm

Scientists Create Semi-Living 'Cyborg' Cells That Could Transform Medicine

Through a complex chemical process, scientists have been able to develop versatile, synthetic 'cyborg' cells in the lab. They share many characteristics of living cells while lacking the ability to divide and grow.

That non-replication part is important. For artificial cells to be useful, they need to be carefully controlled, and that can't happen as easily if they're propagating in the same way that actual cells do.

The researchers behind the new development think these cyborgs could have a huge variety of applications, from improving treatments for diseases like cancer to cleaning up pollution through targeted chemical processes.

The cyborg cells are programmable, do not divide, preserve essential cellular activities, and gain nonnative abilities.

Cell engineering is currently based on two key approaches: genetically remodeling existing cells to give them new functions (more flexible but also able to reproduce) and building synthetic cells from scratch (which can't replicate but have limited biological functions).

These cyborg cells are the result of a new, third strategy. The researchers took bacterial cells as their foundation and added elements from an artificial polymer. Once inside the cell, the polymer was exposed to ultraviolet light to build it into a hydrogel matrix by cross-linking, mimicking a natural extracellular matrix.

While able to maintain much of their normal biological functions, these cyborg cells proved to be more resistant to stressors like high pH and antibiotic exposure – stressors that would kill off normal cells. Much like actual cyborgs, they're tough.

Cyborg cells preserve essential functions, including cellular metabolism, motility, protein synthesis, and compatibility with genetic circuits.

Lab tests on tissue samples showed that the newly developed cells were able to invade cancer cells, highlighting the potential of these modified biological building blocks for health treatments further down the line – they could one day be used to deliver drugs to very specific parts of the body.

he researchers say they now want to experiment with the use of different materials to create these cells, as well as investigate how they could be used.

It's also not clear exactly what is stopping the cells from replicating, which needs to be determined. The authors think the hydrogel matrix may stop cell division by inhibiting cell growth or DNA replication, or both.

The blending of the natural and the artificial demonstrated here in some ways takes the best elements of both, opening up new possibilities – a state of "quasi vita" or "almost life", as the researchers put it.

https://onlinelibrary.wiley.com/doi/10.1002/advs.202204175

Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 12:28pm

Harmful bacteria can elude predators when in mixed colonies

 Efforts to fight disease-causing bacteria by harnessing their natural predators could be undermined when multiple species occupy the same space, according to a new study.

When growing in mixed colonies, some harmful bacteria may be able to withstand attacks from the bacteria and viruses that target them by finding protection inside groups of rival species, according to a report published in the Proceedings of the National Academy of Sciences (PNAS).

The researchers found that the intestinal bacterium Escherichia coli became surrounded by tightly packed colonies of Vibrio cholerae—which causes the deadly disease cholera—when the species were grown together. These clusters protected E. coli from the bacteria Bdellovibrio bacteriovorus that preys on both species individually, but in the study could only kill the outer layer of V. cholerae. This left the unscathed cells of E. coli and V. cholerae insulated within the colonies free to multiply.

The findings add a new layer of complication to the development of biological antimicrobials, wherein bacteria-killing bacteria or viruses—known as bacteriophages—are deployed to fight infections.

For E. coli, if it grew with V. cholerae, it could do better than on its own, but V. cholerae did worse. It's fascinating that growing together had opposite effects on each species' chances of survival. This new research shows that the way prey populations can resist or not resist predators can be very different in multispecies conditions. The efficacy of bacteriophages and predatory bacteria to kill off harmful bacteria might depend on the other species their prey are living with, and on the biofilm structures they produce alone versus together.

These organisms can be more effective than antibiotics at penetrating bacterial colonies, or biofilms, and have emerged as a possible supplement or alternative to antibiotics. Bacteria worldwide have become more resistant to antibiotics due to the drugs' overuse.

Most of earlier research on predatory bacteria and phages, however, has focused on liquid cultures or single-species biofilms, not on mixed colonies like we see in human eco-systems. 

This work highlights the importance of studying other examples of multispecies biofilm structures. What the scientists  saw in this work will apply to other cases, but it's a question of when and to what extent.

Benjamin R. Wucher et al, Breakdown of clonal cooperative architecture in multispecies biofilms and the spatial ecology of predation, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2212650120

James B. Winans et al, Multispecies biofilm architecture determines bacterial exposure to phages, PLOS Biology (2022). DOI: 10.1371/journal.pbio.3001913

Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 12:07pm

Scientists first in the world to regenerate diseased kidney cells

In a world first, scientists at Duke-NUS Medical School, the National Heart Center Singapore (NHCS) and colleagues in Germany have shown that regenerative therapy to restore impaired kidney function may soon be a possibility.

In a preclinical study reported in Nature Communications, the team found that blocking a damaging and scar-regulating protein called interleukin-11 (IL-11) enables damaged kidney cells to regenerate, restoring impaired kidney function due to disease and acute injuries.

Searching for ways to restore the kidney's ability to regenerate damaged cells, researchers investigated the role of IL-11, which is known to trigger scarring in other organs, including the liver, lungs and heart, in acute and chronic kidney disease.

Their findings implicate the protein in triggering a cascade of molecular processes in response to kidney injury that leads to inflammation, fibrosis (scarring) and loss of function. They also discovered that inhibiting IL-11 with a neutralizing antibody can prevent and even reverse kidney damage in this setting.

They found that IL-11 is detrimental to kidney function and triggers the development of chronic kidney disease. They also showed that anti-IL11 therapy can treat kidney failure, reverse established chronic kidney disease, and restore kidney function by promoting regeneration in mice, while being safe for long term use.

More specifically, the researchers showed that renal tubular cells, which line the tiny tubes inside kidneys, release IL-11 in response to kidney damage. This turns on a signaling cascade that ultimately leads to increased expression of a gene, called Snail Family Transcriptional Repressor 1 (SNAI1), which arrests cellular growth and promotes kidney dysfunction.

In a preclinical model of human diabetic kidney disease, turning off this process by administering an antibody that binds to IL-11 led to proliferation of the kidney tubule cells and reversal of fibrosis and inflammation, resulting in the regeneration of the injured kidney and the restoration of renal function.

While clinical trials of an antibody that binds to another pro-fibrotic molecule called transforming growth factor beta have been unsuccessful, this new approach brings hope of a new target.  This work has shown that scientists  can restore function to a damaged kidney.

This discovery could be a real game-changer in the treatment of chronic kidney disease—which is a major public health concern globally—bringing us one step closer to delivering the benefits promised by regenerative medicine.

Anissa A. Widjaja et al, Targeting endogenous kidney regeneration using anti-IL11 therapy in acute and chronic models of kidney disease, Nature Communications (2022). DOI: 10.1038/s41467-022-35306-1

Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 11:52am

"Car brain" heard about it? It seems driving culture gives us a car brain, according to new research.

One of the conditions suffered by car-brained people is the belief in superiority of cars as a means of transport at the expense of bicycles, public transport and walking. 

I was surprised to read several of the conditions suffered by "car brained" people. Some of them even think drinking and driving is okay even if this causes accidents and kills people! 

Hmm! No wonder the accident rate is increasing day by day.

Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 11:35am

Bacteria use dogma-defying DNA packaging

Some bacteria have a bizarre way of packaging chromosomes and regulating gene expression: they use proteins that weren’t thought to exist in bacteria at all. Researchers report that proteins called histones seem to coat regions of the bacterial chro... in two species. This is a marked difference from histones’ function in eukaryotes (which includes animals, plants and fungi), in which the proteins form a spool for DNA to wind around. The researchers surveyed thousands of bacterial genomes and found histone-like proteins in about 2%. For now, it’s unclear what the histones might be doing, and how their unusual mode of action might help the bacteria to survive.

https://www.biorxiv.org/content/10.1101/2023.01.26.525422v1?utm_sou...

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Driving culture gives us ‘car brain’

People seem to be more likely to excuse the negative effects of driving — such as pollution and accidents — than those in other areas of life. In a survey of 2,157 drivers and non-drivers in the United Kingdom, roughly half were asked to rate a statement about cars. The others were given an almost identical sentence about another issue. For example, 75% agreed that people shouldn’t smoke in highly populated areas where others have to breathe in the fumes — but only 17% agreed that people shouldn’t drive in highly populated areas. The researchers suggest that this ‘motonormativity’ inhibits our ability to think objectively about how we use cars.

https://psyarxiv.com/egnmj/

Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 11:13am

Global study shows influences of climate change on terrestrial ecosystems

In a study published in Nature Geoscience, plant ecologistshave shown how global climate change is impacting the Earth's terrestrial ecosystems. Changes in vegetation activity could in most cases be explained by temperature and soil moisture changes, while changes in solar radiation and atmospheric CO₂ levels seldom played a dominant role.

In some of the ecosystems studied, years of increased vegetation activity have been followed by decreases. Such trend reversals raise the question of whether terrestrial ecosystems will continue to make large contributions to the sequestration of atmospheric carbon.

Researchers 

 linked global remote sensing data from the past 40 years to a novel dynamic model of plant growth. This model allows the identification of the climate factors involved in global climate change that are driving vegetation change.

These factors include air temperature, soil temperature, soil moisture, solar radiation, and atmospheric CO₂ levels. The method allows, for the first time, the attribution of measured changes in vegetation activity to individual climate factors.

Steven I. Higgins et al, Shifts in vegetation activity of terrestrial ecosystems attributable to climate trends, Nature Geoscience (2023). DOI: 10.1038/s41561-022-01114-x

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Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 11:04am

Why icicles are rippled

When you look at these icicles carefully, you may notice that they show a characteristic pattern of ripples—always around one centimeter wide. What causes these ripples? Using an icicle machine of their own design, physicists and chemists investigated this question, and discovered that salt plays an important part in the formation process of the ripples.

 It was discovered that the flow of liquid water caused the ripples to appear. Using pure water, the layer of salty liquid water around the icicle was absent, and the formation process looked more like a dripping candle. When saltier water was used, the icicle was surrounded by a thin film of liquid, salty water, and the flow of that water created the regular ripples. The more salt the water contained, the stronger the process, causing thicker ripples to eventually form.

In nature, water always contains a small concentration of salt. This explains the beautiful structures we find on our gutters and car bumpers in the morning—rippled by a thin layer of slightly salty water that was at work throughout the night.

 Menno Demmenie et al, Growth and Form of Rippled Icicles, Physical Review Applied (2023). DOI: 10.1103/PhysRevApplied.19.024005

Comment by Dr. Krishna Kumari Challa on February 7, 2023 at 9:23am

Scientists detect molten rock layer hidden under Earth's tectonic plates

Scientists have discovered a new layer of partly molten rock under the Earth's crust that might help settle a long-standing debate about how tectonic plates move.

Researchers had previously identified patches of melt at a similar depth. But a new study  revealed for the first time the layer's global extent and its part in plate tectonics.

The molten layer is located about 100 miles from the surface and is part of the asthenosphere, which sits under the Earth's tectonic plates in the upper mantle. The asthenosphere is important for plate tectonics because it forms a relatively soft boundary that lets tectonic plates move through the mantle.

The reasons why it is soft, however, are not well understood. Scientists previously thought that molten rocks might be a factor. But this study shows that melt, in fact, does not appear to notably influence the flow of mantle rocks.

The convection of heat and rock in the mantle are the prevailing influence on the motion of the plates. Although the Earth's interior is largely solid, over long periods of time, rocks can shift and flow like honey.

Showing that the melt layer has no influence on plate tectonics means one less tricky variable for computer models of the Earth.

Junlin Hua, Asthenospheric low-velocity zone consistent with globally prevalent partial melting, Nature Geoscience (2023). DOI: 10.1038/s41561-022-01116-9. www.nature.com/articles/s41561-022-01116-9

Comment by Dr. Krishna Kumari Challa on February 6, 2023 at 11:55am

In the new study, teh researchers delved further into this activation failure, which occurs in the lymph nodes, which filter fluids that drain from nearby tissues. The lymph nodes are where “killer T cells” encounter dendritic cells, which present antigens (tumor proteins) and help to activate the T cells.

To explore why some killer T cells fail to be properly activated, researchers studied mice that had tumors implanted either in the lungs or in the flank. All of the tumors were genetically identical.

The researchers found that T cells in lymph nodes that drain from the lung tumors did encounter dendritic cells and recognize the tumor antigens displayed by those cells. However, these T cells failed to become fully activated, as a result of inhibition by another population of T cells called regulatory T cells.

These regulatory T cells became strongly activated in lymph nodes that drain from the lungs, but not in lymph nodes near tumors located in the flank, the researchers found. Regulatory T cells are normally responsible for making sure that the immune system doesn’t attack the body’s own cells. However, the researchers found that these T cells also interfere with dendritic cells’ ability to activate killer T cells that target lung tumors.

The researchers also discovered how these regulatory T cells suppress dendritic cells: by removing stimulatory proteins from the surface of dendritic cells, which prevents them from being able to turn on killer-T-cell activity.

Further studies revealed that the activation of regulatory T cells is driven by high levels of interferon gamma in the lymph nodes that drain from the lungs. This signaling molecule is produced in response to the presence of commensal bacterial — bacteria that normally live in the lungs without causing infection.

The researchers have not yet identified the types of bacteria that induce this response or the cells that produce the interferon gamma, but they showed that when they treated mice with an antibody that blocks interferon gamma, they could restore killer T cells’ activity.

Interferon gamma has a variety of effects on immune signaling, and blocking it can dampen the overall immune response against a tumor, so using it to stimulate killer T cells would not be a good strategy to use in patients.

Researchers are now exploring other ways to help stimulate the killer T cell response, such as inhibiting the regulatory T cells that suppress the killer-T-cell response or blocking the signals from the commensal bacteria, once the researchers identify them.

Maria Zagorulya, Leon Yim, et al. Tissue-specific abundance of interferon-gamma drives regulatory T cells to restrain DC1-mediated priming of cytotoxic T cells against lung cancer. Immunity. DOI: 10.1016/j.immuni.2023.01.010

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