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Comment by Dr. Krishna Kumari Challa on November 26, 2020 at 10:23am

Researchers uncover the unique way stem cells protect their chromosome ends

Telomeres are specialized structures at the end of chromosomes which protect our DNA and ensure healthy division of cells. According to a new study from researchers at the Francis Crick Institute published in Nature, the mechanisms of telomere protection are surprisingly unique in stem cells.

For the last 20 years, researchers have been working to understand how telomeres protect chromosome ends from being incorrectly repaired and joined together because this has important implications for our understanding of cancer and aging.

In healthy cells, this protection is very efficient, but as we age our telomeres get progressively shorter, eventually becoming so short that they lose some of these protective functions. In healthy cells, this contributes to the progressive decline in our health and fitness as we age. Conversely, telomere shortening poses a protective barrier to tumor development, which cancer cells must solve in order to divide indefinitely.

In somatic cells, which are all the cells in the adult body except stem cells and gametes, we know that a protein called TRF2 helps to protect the telomere. It does this by binding to and stabilizing a loop structure, called a t-loop, which masks the end of the chromosome. When the TRF2 protein is removed, these loops do not form and the chromosome ends fuse together, leading to "spaghetti chromosomes" and killing the cell.

However, in this latest study, Crick researchers have found that when the TRF2 protein is removed from mouse embryonic stem cells, t-loops continue to form, chromosome ends remain protected and the cells are largely unaffected.

As embryonic stem cells differentiate into somatic cells, this unique mechanism of end protection is lost and both t-loops and chromosome end protection become reliant on TRF2. This suggests that somatic and stem cells protect their chromosome ends in fundamentally different ways.

Phil Ruis et al. TRF2-independent chromosome end protection during pluripotency, Nature (2020). DOI: 10.1038/s41586-020-2960-y

https://phys.org/news/2020-11-uncover-unique-stem-cells-chromosome....

Comment by Dr. Krishna Kumari Challa on November 26, 2020 at 10:19am

Scientists discover potential method to starve the bacteria that cause tuberculosis

The infectious disease Tuberculosis (TB) is one of the leading causes of death worldwide.

Researchers have known for some time that the bacteria that causes TB (Mycobacterium tuberculosis) uses our body's cholesterol—a steroid—as a food source. Other relatives of the bacteria that do not cause disease share its ability to break down steroids. In this study scientists identified the structure of an enzyme (acyl CoA dehydrogenase) involved in steroid degradation in another member of the same bacteria family, called Thermomonospora curvata.

Determining the structure of enzymes that metabolize steroids moves scientists and pharmaceutical companies one step closer to creating drugs that can inhibit a similar enzyme found in M. tuberculosis, which would effectively starve TB of its food source. 

Alexander J. Stirling et al. A Key Glycine in Bacterial Steroid-Degrading Acyl-CoA Dehydrogenases Allows Flavin-Ring Repositioning and Modulates Substrate Side Chain Specificity, Biochemistry (2020). DOI: 10.1021/acs.biochem.0c00568

https://phys.org/news/2020-11-scientists-potential-method-starve-ba...

Comment by Dr. Krishna Kumari Challa on November 26, 2020 at 8:22am

Waste fishing gear threatens Ganges wildlife

Waste fishing gear in the River Ganges poses a threat to wildlife including otters, turtles and dolphins, new research shows.

The study says entanglement in fishing gear could harm species including the critically endangered three-striped roofed turtle and the endangered Ganges river dolphin.

Surveys along the length of the river, from the mouth in Bangladesh to the Himalayas in India, show levels of waste fishing gear are highest near to the sea.

Fishing nets—all made of plastic—were the most common type of gear found. local fishers revealed high rates of fishing equipment being discarded in the river—driven by short gear lifespans and lack of appropriate disposal systems.

"Ingesting plastic can harm wildlife, but our threat assessment focussed on entanglement, which is known to injure and kill a wide range of marine species."

The researchers used a list of 21 river species of "conservation concern" identified by the Wildlife Institute for India.

Sarah E. Nelms et al, Riverine plastic pollution from fisheries: Insights from the Ganges River system, Science of The Total Environment (2020). DOI: 10.1016/j.scitotenv.2020.143305

https://phys.org/news/2020-11-fishing-gear-threatens-ganges-wildlif...

Comment by Dr. Krishna Kumari Challa on November 26, 2020 at 7:53am

Tunable coating allows hitch-hiking nanoparticles to slip past the immune system to their target

Nanoparticles are promising drug delivery tools, offering the ability to administer drugs directly to a specific part of the body and avoid the awful side effects so often seen with chemotherapeutics.

But there's a problem. Nanoparticles struggle to get past the immune system's first line of defense: proteins in the blood serum that tag potential invaders. Because of this, only about 1 percent of nanoparticles reach their intended target.

A team of researchers have now  developed an ionic forcefield that prevents proteins from binding to and tagging nanoparticles.

In mouse experiments, nanoparticles coated with the ionic liquid survived significantly longer in the body than uncoated particles and, surprisingly, 50 percent of the nanoparticles made it to the lungs. It's the first time that ionic liquids have been used to protect nanoparticles in the blood stream.

"The fact that this coating allows the nanoparticles to slip past serum proteins and hitch a ride on red blood cells is really quite amazing because once you are able to fight the immune system effectively, lots of opportunities open up.

"Protein-avoidant ionic liquid (PAIL)–coated nanoparticles to increase bloodstream circulation and drive biodistribution" Science Advances (2020). advances.sciencemag.org/lookup … .1126/sciadv.abd7563

https://phys.org/news/2020-11-tunable-coating-hitch-hiking-nanopart...

Comment by Dr. Krishna Kumari Challa on November 26, 2020 at 7:09am

A pocket cooling device based on a cascade mechanism

Recent technological advances have enabled the development of increasingly compact and flexible devices. This includes wearable or portable technology.

Researchers  have recently devised a strategy that could enable the fabrication of portable, compact and flexible electrocaloric cooling devices. This strategy, outlined in a paper published in Nature Energy, is based on a four-layer cascade mechanism that enables a significant temperature lift in a user's surroundings.

This pocket cooling device designed is made of an electrocaloric polymer film. When voltage is applied to the polymer, the device heats up due to a significant entropy reduction. Conversely, when the voltage is removed, the device's temperature drops.

Yuan Meng et al. A cascade electrocaloric cooling device for large temperature lift, Nature Energy (2020). DOI: 10.1038/s41560-020-00715-3

https://techxplore.com/news/2020-11-pocket-cooling-device-based-cas...

Comment by Dr. Krishna Kumari Challa on November 25, 2020 at 9:40am

Scientists Detect 'Superbolts' 1,000 Times Brighter Than Typical Lightning Strikes

scientists have just detected a new extreme in hotspots of lightning activity called 'superbolts': intense lightning strikes that shine up to 1,000 times brighter than typical lightning strikes. 

The observations come from researchers at the US Los Alamos National Laboratory, who used satellites to measure the extreme lightning events. The results force a rethink on what constitutes a superbolt, and shed new light on how and where superbolts originate. Unlike ground-based monitoring systems, which detect radio waves, the GLM measures the total brightness (optical energy) of lightning bolts within clouds, between clouds, plus lightning that strikes the ground.

There's also the question of whether superbolts are supercharged by some unique phenomenon, or if they're just bigger, brighter strikes of the usual lightening variety.

Understanding these extreme events is important because it tells us what lightning is capable of.

The researchers combed two years of data for lightning strikes that shone 100 times brighter than a typical bolt detected from space, and found about 2 million events intense enough to be called a superbolt – roughly one in every 300 lightning events. When the researchers raised the bar to lightning events at least 1,000 times brighter than an ordinary lightning strike, they identified key hotspots of energetic superbolt activity.

Scientists found one lightning stroke that exceeded 3 terawatts of power – thousands of times stronger than ordinary lightning detected from space.

The most powerful superbolts (producing more than 350 gigawatts of power) resulted from rare positively charged cloud-to-ground events, rather than negatively charged cloud-to-ground events, which characterises most lightning strikes.

The results also showed that superbolts often occur over the ocean and tend to spark from megaflashes, which stretch hundreds of miles horizontally from tip to tail.

Oceanic storm systems, particularly during the winter, and especially those located around Japan are shown to produce these intense superbolts.

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JD033378

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020JD033377

https://www.sciencealert.com/study-finds-superbolts-shine-1000-time...

Comment by Dr. Krishna Kumari Challa on November 25, 2020 at 8:47am

Oxford vaccine: How did they make it so quickly?

Ten years' vaccine work achieved in about 10 months. Yet no corners cut in designing, testing and manufacturing.

https://www.bbc.com/news/health-55041371

Comment by Dr. Krishna Kumari Challa on November 25, 2020 at 8:28am

Scientists find water microdroplets can transform into hydrogen peroxide when condensing on cold surfaces

In its bulk liquid form, whether in a bathtub or an ocean, water is a relatively benign substance with little chemical activity. But down at the scale of tiny droplets, water can turn surprisingly reactive,  researchers have discovered.

In microdroplets of water, just millionths of a meter wide, a portion of the H₂O molecules present can convert into a close chemical cousin, hydrogen peroxide, H₂O₂, a harsh chemical commonly used as a disinfectant and hair bleaching agent.

Stanford scientists first reported this unexpected behavior in forcibly sprayed microdroplets of water last year. Now in a new study, the research team has shown the same Jekyll-and-Hyde transformation happens when microdroplets simply condense from the air onto cold surfaces. The new results suggest that water's hydrogen peroxidetransformation is a general phenomenon, occurring in fogs, mists, raindrops and wherever else microdroplets form naturally.

The surprising discovery could lead to greener methods for disinfecting surfaces or promoting chemical reactions.

Jae Kyoo Lee et al. Condensing water vapor to droplets generates hydrogen peroxide, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2020158117

https://phys.org/news/2020-11-scientists-microdroplets-hydrogen-per...

Comment by Dr. Krishna Kumari Challa on November 25, 2020 at 7:41am

COVID-19: Air quality influences the pandemic

The correlation between the high concentration of fine particles and the severity of influenza waves is well known to epidemiologists. An interdisciplinary team from the University of Geneva (UNIGE) and the ETH Zürich spin-off Meteodat investigated possible interactions between acutely elevated levels of fine particulate matter and the virulence of the coronavirus disease. Their results, published in the journal Earth Systems and Environment, suggest that high concentrations of particles less than 2.5 micrometers in size may modulate, or even amplify, the waves of SARS-CoV-2 contamination and explain in part the particular profile of the COVID-19 pandemic. The increase in fine particles is generally favored by air temperature inversions, characterized by fog situations, or by Saharan dust intrusions. The study provides preventive measures related to air pollution to limit future outbreaks of morbidity and mortality due to the coronavirus.

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India's love affair with coal cools as pressure grows on sector

Funding for coal projects in India has plunged for the second straight year, new figures showed Tuesday, as the world's second biggest coal importer weans itself off the dirty fuel.

Comment by Dr. Krishna Kumari Challa on November 25, 2020 at 7:28am

Antimicrobial soap additive worsens fatty liver disease in mice

Researchers found evidence that triclosan—an antimicrobial found in many soaps, toothpastes and other household items—worsens fatty liver disease in mice fed a high-fat diet.

The study also reveals also details the molecular mechanisms  by which triclosan disrupts metabolism and the gut microbiome, while also stripping away liver cells' natural protections. Triclosan's increasingly broad use in consumer products presents a risk of liver toxicity for humans.

The study shows that common factors that we encounter in every-day life—the ubiquitous presence of triclosan, together with the prevalence of high consumption of dietary fat —constitute a good recipe for the development of fatty liver disease in mice.

In a 2014 mouse study, the team found triclosan exposure promoted liver tumor formation by interfering with a protein responsible for clearing away foreign chemicals in the body. In the latest study, the researchers fed a high-fat diet to mice with type 1 diabetes. As previous studies have shown, the high-fat diet led to non-alcoholic fatty liver disease (NAFLD). In humans, NAFLD is an increasingly common condition that can lead to liver cirrhosis and cancer. Diabetes and obesity are risk factors for NAFLD. Some of the mice were also fed triclosan, resulting in blood concentrations comparable to those found in human studies. Compared to mice only fed a high-fat diet, triclosan accelerated the development of fatty liver and fibrosis. According to the study, here's what's likely happening: Eating a high-fat diet normally tells cells to produce more fibroblast growth factor 21, which helps protects liver cells from damage. Tukey and team discovered that triclosan messes with two molecules, ATF4 and PPARgamma, which cells need to make the protective growth factor. Not only that, the antimicrobial also disrupted a variety of genes involved in metabolism. In addition, the mice exposed to triclosan had less diversity in their gut microbiomes—fewer types of bacteria living in the intestines, and a makeup similar to that seen in patients with NAFLD. Less gut microbiome diversity is generally associated with poorer health. So far, these findings have only been observed in mice who ingested triclosan. But since these same molecular systems also operate in humans, the new information will help researchers better understand risk factors for NAFLD, and give them a new place to start in designing potential interventions to prevent and mitigate the condition.

Mei-Fei Yueh et al, Triclosan leads to dysregulation of the metabolic regulator FGF21 exacerbating high fat diet-induced nonalcoholic fatty liver disease, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.2017129117

https://medicalxpress.com/news/2020-11-antimicrobial-soap-additive-...

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