Gut flora composition may impact susceptibility to konzo, a neurological disease caused by world staple crop cassava

Konzo is a severe, irreversible neurologic disease that results in paralysis. It occurs after consuming poorly processed cassava -- a manioc root and essential crop for DRC and other low-income nations. Poorly processed cassava contains linamarin, a cyanogenic compound. While enzymes with glucosidase activity convert starch to simple sugars, they also break down linamarin, which then releases cyanide into the body.

 Differences between gut flora and genes from konzo-prone regions of the Democratic Republic of Congo (DRC) may affect the release of cyanide after poorly processed cassava is consumed, according to a study with 180 children. Cassava is a food security crop for over half a billion people in the developing world. Children living in high-risk konzo areas have high glucosidase (linamarase) microbes and low rhodanese microbes in their gut, which could mean more susceptibility and less protection against the disease, suggest  researchers who led the study published in Nature Communications.

Knowing who is more at risk could result in targeted interventions to process cassava better or try to diversify the diet. An alternative intervention is to modify the microbiome to increase the level of protection. This is, however, a difficult task which may have unintended consequences and other side effects.

While the gut microbiome is not the sole cause of disease given that environment and malnourishment play a role, it is a required modulator. "Simply stated, without gut microbes, linamarin and other cyanogenic glucosides would pose little to no risk to humans."

1. Matthew S. Bramble, Neerja Vashist, Arthur Ko, Sambhawa Priya, Céleste Musasa, Alban Mathieu, D’ Andre Spencer, Michel Lupamba Kasendue, Patrick Mamona Dilufwasayo, Kevin Karume, Joanna Nsibu, Hans Manya, Mary N. A. Uy, Brian Colwell, Michael Boivin, J. P. Banae Mayambu, Daniel Okitundu, Arnaud Droit, Dieudonné Mumba Ngoyi, Ran Blekhman, Desire Tshala-Katumbay, Eric Vilain. The gut microbiome in konzo. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-25694-1

A Clever 'Gene Silencing' Injection Has Been Approved For Treating High Cholesterol

cholesterol-busting jab to save thousands of lives in UK

The revolutionary new treatment, Inclisiran, is delivered as an injection twice a year and can be used alongside statins, adding to the options available to patients to help control their cholesterol levels.

It has been estimated that Inclisiran could prevent 55,000 heart attacks and strokes, saving 30,000 lives within the next decade.

It will mainly be prescribed to patients who suffer with a genetic condition that leads to high cholesterol, those who have already suffered a heart attack or stroke, or those who haven't responded well to other cholesterol-lowering drugs, such as statins.

This is an emerging therapeutic technique that works by targeting the underlying causes of a disease, rather than the symptoms it causes. It does this by targeting a particular gene, and preventing it from making the protein that it produces.

Until now, most treatments using gene silencing technology have been used to treat rare genetic diseases. This means the cholesterol jab will be one of the first gene silencing drugs used to treat people on a wider scale.

Researchers are also currently investigating whether gene silencing could be used to treat a wide variety of health conditions, including Alzheimer's disease and cancer.

Gene silencing drugs work by targeting a specific type of RNA (ribonucleic acid) in the body, called "messenger" RNA. RNAs are found in every cell of the body, and play an important role in the flow of genetic information.

But messenger RNA (mRNA) is one of the most important types of RNA our body has, as it copies and carries genetic instructions from our DNA and makes specific proteins depending on the instructions.

In the case of the cholesterol jab, gene silencing works by targeting a protein called PCSK9 and degrading it. This protein is involved in regulating cholesterol in our bodies, but occurs in excess in people with high levels of LDL cholesterol (the "bad" cholesterol). Preventing this protein from being produced in the first place will reduce cholesterol levels.

https://www.england.nhs.uk/2021/09/nhs-cholesterol-busting-jab-to-s...

In this case, the siRNA is designed to specifically target the mRNA which carries instructions for the PCSK9 protein. It binds to its target mRNA and destroys the instructions, which significantly reduces the amount of these proteins that are produced.

Gene therapies are usually delivered using a viral vector – a virus-like vehicle that delivers genes to our cells in the same way a virus might infect them. So far, viral vector therapies have been used to treat rare genetic blood disorders, genetic blindness and spinal muscular atrophy.

Although viral vectors are very effective with one treatment, it may be impossible to deliver a second dose if needed due to adverse immune reactions. These drugs are also extremely costly.

Because of this, many of the gene silencing drugs currently being investigated are delivered using a different technique. Known as non-viral vector gene therapies, these deliver the drug using a nanoparticle which protects it from degradation in the blood so it can be delivered specifically to the target – such as the liver, which is the target of the cholesterol jab.

https://www.sciencealert.com/this-gene-silencing-injection-was-just...

Part 2

Our mobile phones are covered in bacteria and viruses… and we never wash them

Mechanical buckling of petals produces iridescent patterns visible to bees

People only pay attention to new information when they want to

A new paper in the Journal of the European Economic Association, published by Oxford University Press, indicates that we tend to listen to people who tell us things we'd like to believe and ignore people who tell us things we'd prefer not to be true. As a result, like-minded people tend to make one another more biased when they exchange beliefs with one another.

While it would reasonable to think that people form decisions based on evidence and experience alone, previous research has demonstrated that decision makers have "motivated beliefs;" They believe things in part because they would like such things to be true. Motivated beliefs (and the reasoning that leads to them) can generate serious biases. Motivated beliefs have been speculated to explain the proliferation of misinformation on online forums.

The experiment conducted supports a lot of popular suspicions about why biased beliefs might be getting worse in the age of the internet. We now get a lot of information from social media and we don't know much about the quality of the information we're getting. As a result, we're often forced to decide for ourselves how accurate various opinions and sources of information are and how much stock to put in them. Our results suggest that people resolve this quandary by assigning credibility to sources that are telling us what we'd like to hear and this can make biases due to motivated reasoning a lot worse over time.

Ryan Oprea et al, Social Exchange of Motivated Beliefs, Journal of the European Economic Association (2021). DOI: 10.1093/jeea/jvab035

https://phys.org/news/2021-09-people-attention.html?utm_source=nwle...

Study links severe COVID-19 to increase in self-attacking antibodies

Hospitalized COVID-19 patients are substantially more likely to harbor autoantibodies—antibodies directed at their own tissues or at substances their immune cells secrete into the blood—than people without COVID-19, according to a new study.

Autoantibodies can be early harbingers of full-blown autoimmune disease.

If you get sick enough from COVID-19 to end up in the hospital, you may not be out of the woods even after you recover.

The scientists looked for autoantibodies in blood samples drawn during March and April of 2020 from 147 COVID-19 patients at the three university-affiliated hospitals and from a cohort of 48 patients at Kaiser Permanente in California. Blood samples drawn from other donors prior to the COVID-19 pandemic were used as controls.

The researchers identified and measured levels of antibodies targeting the virus; autoantibodies; and antibodies directed against cytokines, proteins that immune cells secrete to communicate with one another and coordinate their overall strategy.

Upward of 60% of all hospitalized COVID-19 patients, compared with about 15% of healthy controls, carried anti-cytokine antibodies, the scientists found. This could be the result of immune-system overdrive triggered by a virulent, lingering infection. In the fog of war, the abundance of cytokines may trip off the erroneous production of antibodies targeting them.

If any of these antibodies block a cytokine's ability to bind to its appropriate receptor, the intended recipient immune cell may not get activated. That, in turn, might buy the virus more time to replicate and lead to a much worse outcome.

Part1

In some cases, the presence of those newly detected autoantibodies may reflect an increase, driven by the immune response, of antibodies that had been flying under the radar at low levels, Utz said. It could be that inflammatory shock to the systems of patients with severe COVID-19 caused a jump in previously undetectable, and perhaps harmless, levels of autoantibodies these individuals may have been carrying prior to infection.

In other cases, autoantibody generation could result from exposure to viral materials that resemble our own proteins.

--

It's possible that, in the course of a poorly controlled SARS-CoV-2 infection—in which the virus hangs around for too long while an intensifying immune response continues to break viral particles into pieces—the immune system sees bits and pieces of the virus that it hadn't previously seen," he said. "If any of these viral pieces too closely resemble one of our own proteins, this could trigger autoantibody production."

The finding bolsters the argument for vaccination. Vaccines for COVID-19 contain only a single protein—SARS-CoV-2's so-called spike protein—or the genetic instructions for producing it. With vaccination, the immune system is never exposed to—and potentially confused by—the numerous other novel viral proteins generated during infection.

In addition, vaccination is less intensely inflammatory than an actual infection, so there's less likelihood that the immune system would be confused into generating antibodies to its own signaling proteins or to the body's own tissues.

Patients who, in response to vaccination, quickly mount appropriate antibody responses to the viral spike protein should be less likely to develop autoantibodies.

Indeed, a recent study in Nature showed that, unlike SARS-CoV-2 infection, the COVID-19 vaccine produced by Pfizer doesn't trigger any detectable generation of autoantibodies among recipients.

1. Sarah Esther Chang, Allan Feng, Wenzhao Meng, Sokratis A. Apostolidis, Elisabeth Mack, Maja Artandi, Linda Barman, Kate Bennett, Saborni Chakraborty, Iris Chang, Peggie Cheung, Sharon Chinthrajah, Shaurya Dhingra, Evan Do, Amanda Finck, Andrew Gaano, Reinhard Geßner, Heather M. Giannini, Joyce Gonzalez, Sarah Greib, Margrit Gündisch, Alex Ren Hsu, Alex Kuo, Monali Manohar, Rong Mao, Indira Neeli, Andreas Neubauer, Oluwatosin Oniyide, Abigail E. Powell, Rajan Puri, Harald Renz, Jeffrey Schapiro, Payton A. Weidenbacher, Richard Wittman, Neera Ahuja, Ho-Ryun Chung, Prasanna Jagannathan, Judith A. James, Peter S. Kim, Nuala J. Meyer, Kari C. Nadeau, Marko Radic, William H. Robinson, Upinder Singh, Taia T. Wang, E. John Wherry, Chrysanthi Skevaki, Eline T. Luning Prak, Paul J. Utz. New-onset IgG autoantibodies in hospitalized patients with COVID-19. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-25509-3

https://medicalxpress.com/news/2021-09-links-severe-covid-self-atta...

part 2

Researchers find immune cells that guard frequent site of cancer spread

In the progressing field of immunotherapy, surprisingly little is known about immunity to metastatic tumors in locations such as lymph nodes, a frequent place where cancers first spread. Not only do lymph nodes act as a gateway for cancer cells to travel throughout the body, but they are also home to infection-fighting white blood cells called T cells. In some cases, T cells in lymph nodes activate to kill invading cancer cells. In other cases, that process clearly fails.

While T cells can freely travel from lymph nodes into the bloodstream and back to the lymph nodes, researchers in Turk's lab have discovered a novel population of tumor-fighting T cells that do not circulate, but rather stay in lymph nodes where they provide protection against melanoma. "These T cells, for whatever reason, have changed their program and stay in the lymph nodes where they persist and kill tumor cells for many months while never entering circulation," says Turk.

These long-lived T cells, called "lymph node resident memory T cells," were shown to counteract melanoma spreading in mice. Turk's team found that when melanoma cells were put back into mice that had been cured of cancer with immunotherapy a month earlier, the lymph nodes were still resistant to the cancer—the melanoma would not grow.

Researchers identified T cells with similar characteristics in melanoma-invaded patient lymph nodes, showing that similar populations exist in humans.

Computational analysis of melanoma specimen data from The Cancer Genome Atlas revealed that the presence of T cells with this gene signature predicted better outcomes and improved survival for human melanoma patients with lymph node metastases. "These studies reveal a new population of T cells that is vital for counteracting the earliest stages of cancer metastasis.

Resident memory T cells in regional lymph nodes mediate immunity to metastatic melanoma, Immunity, DOI: 10.1016/j.immuni.2021.08.019

https://medicalxpress.com/news/2021-09-immune-cells-frequent-site-c...

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Scientists pinpoint the uncertainty of our working memory

The human brain regions responsible for working memory content are also used to gauge the quality, or uncertainty, of memories, a team of scientists has found. Its study uncovers how these neural responses allow us to act and make decisions based on how sure we are about our memories.

Access to the uncertainty in our working memory enables us to determine how much to 'trust' our memory in making decisions.

This research is the first to reveal that the neural populations that encode the content of working memory also represent the uncertainty of memory.

Working memory, which enables us to maintain information in our minds, is an essential cognitive system that is involved in almost every aspect of human behavior—notably decision-making and learning.

For example, when reading, working memory allows us to store the content we just read a few seconds ago while our eyes keep scanning through the new sentences. Similarly, when shopping online, we may compare, "in our mind," the item in front of us on the screen with previous items already viewed and still remembered.

"It is not only crucial for the brain to remember things, but also to weigh how good the memory is: How certain are we that a specific memory is accurate?

 The study results yielded the first evidence that the human brain registers both the content and the uncertainty of working memory in the same cortical regions.

The knowledge of uncertainty of memory also guides people to seek more information when we are unsure of our own memory.

Joint representation of working memory and uncertainty in human cortex, Neuron (2021). DOI: 10.1016/j.neuron.2021.08.022

https://medicalxpress.com/news/2021-09-scientists-uncertainty-memor...

New immunotherapy method turns activated specifically in tumor

Immunotherapy drugs are promising new weapons in the fight against cancer, but they are so strong that they can be toxic to the rest of the human body. The basic idea behind immunotherapy drugs is simple. Doctors inject special kinds of drugs, especially proteins such as antibodies and cytokines prepared or modified in a lab, into a patient, where they activate the patient’s immune cells –T-cells, NK cells, and so on – and help these cells fight the tumor. In short, immunotherapy drugs work like a powerful cocktail that boosts a patient’s own immune system.

After being prescribed by a doctor, immunotherapy drugs are administered intravenously.

Once inside the body, the drugs spread all over – not just where the tumor or any metastases are located. The problem is that the proteins in the drugs are so strong that they damage healthy tissue. Many of the immunotherapy treatments already out there have proven to be highly effective against cancer in preclinical studies. But they often can’t be used to save people because they’re too toxic to the rest of the body. The treatments that are used in patients today have been toned down so they’re less potent. That makes them safer, but also less effective at destroying tumors. The aim of this new method is to keep all the potency of immunotherapy, because it will be an important treatment option for cancer patients.
Researchers, therefore, developed a method whereby the immunotherapy proteins are activated only when they come into the tumor tissues.  This method draws on techniques from both chemistry and immune engineering.

The tumor microenvironment is different from the rest of the body. The pH is lower, meaning it’s more acidic, and it has a high reducing potential. Researchers used these facts, already known to scientists, to develop a kind of polymer shield for the protein drugs that would let them travel harmlessly through the body until they reach the tumor.

That shield is designed to break down when exposed to the unique chemical environment in the tumor tissue. Chemical reactions in the tumour microenvironment break the bonds at the protein surface, thereby removing the polymer shield. The protein drugs are then free to activate the patient’s cancer-fighting lymphocytes selectively in the tumour tissue.

Zhao, Y. ; Xie, Y.-Q. ; Van Herck, S. ; Nassiri, S. ; Gao, M. ; Guo...

https://actu.epfl.ch/news/new-immunotherapy-becomes-activated-speci...

https://www.myscience.ch/en/news/2021/new_immunotherapy_becomes_act...

https://researchnews.cc/news/8892/New-immunotherapy-method-turns-ac...

Chemically masked cytokines and antibodies turn active selectively in tumors as safer cancer immunotherapies. Credit: Yu Zhao 2021 EPFL

How to modify RNA: Crucial steps for adding chemical tag to transfer RNA revealed

The chemical steps in an important cellular modification process that adds a chemical tag to some RNAs have been revealed in a new study. Interfering with this process in humans can lead to neuronal diseases, diabetes, and cancers. A research team has imaged a protein that facilitates this RNA modification in bacteria, allowing the researchers to reconstruct the process. A paper describing the modification process appears Sept. 15 in the journal Nature.

Transfer RNAs (tRNA) are the RNAs that "read" the genetic code and translate it into a sequence of amino acids to make a protein. The addition of a chemical tag—a methyl sulfur group—to a particular location on some tRNAs improves their ability to translate messenger RNA into proteins. When this modification process—called methylthiolation—doesn't occur properly, mistakes can be incorporated into the resulting proteins, which in humans can lead to neuronal disease, cancer, and increased risk of developing Type 2 diabetes.

Methylthiolation is ubiquitous across bacteria, plants, and animals. In this study, researchers  determined the structure of a protein called MiaB to better understand its role in facilitating this important modification process in bacteria.

Structural basis for tRNA methylthiolation by the radical SAM enzyme MiaB, Nature (2021). DOI: 10.1038/s41586-021-03904-6 , www.nature.com/articles/s41586-021-03904-6

https://phys.org/news/2021-09-rna-crucial-adding-chemical-tag.html?...

Differences in cellular signaling offer clues to insulin resistance

In what could be a starting point for new therapeutics to tackle insulin resistance, a major driver of type 2 diabetes and metabolic syndrome present in 20–30 percent of the general U.S. population, researchers recently found that insulin resistance in the general population seems likely to be caused by a series of cell-specific signaling defects, some of which appear to be sex specific.

In addition, only a portion of the defects are shared with those seen in diabetes, pointing towards the existence of novel pathways behind insulin resistance in the general population.

Most people know that insulin is an important hormone for controlling blood glucose, but most people don't realize how important insulin is for all aspects of metabolism—not just sugar, but lipids, amino acids, and proteins

Insulin resistance, that is the failure of the body to respond normally to insulin, is very common in the population, not just in people with diabetes or obesity, and these individuals are at high risk for developing these metabolic disorders.

The research is based on a stem-cell modeling system called iMyos that can be used to investigate cell-specific changes in signaling in combination with a technique called phosphoproteomics.

Specifically, the researchers used stem cells derived from blood cells of individuals without diabetes who were either insulin sensitive or resistant.

The researchers could then investigate differences in cellular signaling, both in the absence and presence of insulin stimulation, to determine how insulin resistance or sensitivity affected signaling in a series of different pathways.

In what emerges as a complex picture, they found large differences in phosphoproteome signatures based on insulin sensitivity status but also based on the sex of the cell donors.

Nida Haider et al, Signaling defects associated with insulin resistance in non-diabetic and diabetic individuals and modification by sex, Journal of Clinical Investigation (2021). DOI: 10.1172/JCI151818

Part 1

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Researchers identified a comprehensive network of cell signaling defects in non-diabetic individuals and also uncovered critical nodes of signaling changes shared with type 2 diabetic patients.

These critical nodes where signaling was altered go well beyond the classical insulin signaling, opening a whole new view of insulin resistance. One of the most striking and surprising findings was that many of the signaling changes were sex specific.

Thus, even in the absence of adding sex hormones, these male and female cells showed differences in their phosphoproteome fingerprint. This was very unexpected.

Importantly, the investigators also found that the differences and changes did reflect on multiple downstream biological processes, implying that therapeutic interventions at specific points in the signaling cascade will likely affect biological outcomes.

"Further investigation will be needed to identify the regulators that are responsible for the phosphoproteome changes associated with insulin resistance, and for the drastic differences by sex. "Unraveling these critical nodes in insulin resistance will be able to serve as novel targets for the development of future therapies."

https://medicalxpress.com/news/2021-09-differences-cellular-clues-i...

Part 2

You will no longer need a password for Microsoft accounts

Microsoft announced in a blog post recently that it will give users the option to access their accounts without using a password.

Users can choose between downloading the Microsoft Authenticator app - a security key a verification code sent to your phone or secondary email address, or Windows Hello, a biometric option that involves scanning your face, iris or fingerprint.

With the Authenticator app, for example, users get notified on their smartphone during a login attempt, and receive a prompt confirming their identity.

The new option tackles two problems: complex passwords people can't remember and passwords that do not offer enough security because they're too simple.

The feature will be rolled out in the coming weeks.

https://www.microsoft.com/insidetrack/blog/no-more-passwords-the-re...

Alzheimer’s disease: hyperbaric oxygen proposed as treatment in new study

Alzheimer’s disease, the most common form of dementia, has long been associated with a build-up of plaques (clumps of protein) in the brain. Scientists in Israel have shown that a type of oxygen therapy can stop new plaques forming and even remove existing plaques in mice with Alzheimer’s.

The scientists used a mouse model of Alzheimer’s disease called 5xFAD. The genetically modified mice were treated with hyperbaric oxygen therapy to see if they could halt or slow the disease progression.

Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurised chamber. In the chamber, the air pressure is increased two to three times higher than normal air pressure. It is commonly used to treat decompression sickness (a condition scuba divers can suffer from), carbon monoxide poisoning, and some forms of stroke or brain injury. It works by forcing increased oxygenation of tissues with low oxygen levels (hypoxia). And it could improve blood flow to the brain to nourish brain cells that are usually deprived of blood, and hence oxygen, in Alzheimer’s disease.

The scientists, from the University of Tel Aviv, treated 15 six-month-old mice (about 30 human years) with hyperbaric oxygen therapy for an hour a day, five days a week for four weeks. The therapy not only reduced the number and size of plaques in the brains of the mice, it also slowed the formation of new plaques, compared with a control group of mice who did not receive hyperbaric oxygen therapy.

Blood flow to the brain is reduced in people with Alzheimer’s. This study showed increased blood flow to the brain in the mice receiving oxygen therapy, which helps with the clearance of plaques from the brain, and reduces inflammation – a hallmark of Alzheimer’s.

By improving blood flow to the brain, reducing plaque levels and reducing hypoxia, the mice undergoing daily oxygen therapy began to show improvements to their cognitive abilities, such as their spatial recognition memory as well as contextual memory – the ability to remember emotional, social, spatial or temporal circumstances related to an event.

The researchers then used these findings to assess the effectiveness of oxygen therapy in six people over the age of 65 with cognitive decline. They found that 60 sessions of oxygen therapy, over 90 days, increased blood flow in certain areas of the brain and significantly improved the patients’ cognitive abilities – improved memory, attention and information processing speed.

Taken together, these findings suggest that oxygen therapy may be able to reduce cognitive decline associated with ageing and dementia in both mice and people.

https://www.aging-us.com/article/203485/text

https://theconversation.com/alzheimers-disease-hyperbaric-oxygen-pr...

Ancient marsupial ‘junk DNA’ might be useful after all, scientists say

For The First Time, Scientists Have Entangled Three Qubits on Silicon

Scientists have got three entangled qubits operating together on a single piece of silicon.

It's the first time that's ever been done, and the silicon material is important: that's what the electronics inside today's computers are based on, so it's another advancement in  bridging the gap between the quantum and classical computing realms.

Qubits are the quantum equivalent of the standard bits inside a conventional computer: they can represent several states at once, not just a 1 or a 0, which – in theory – means an exponential increase in computing power.

The real magic happens when these qubits are entangled, or tightly linked together.

As well as increases in computing power, the addition of more qubits means better error correction – a key part of keeping quantum computers stable enough to use them outside of research laboratories.

Two-qubit operation is good enough to perform fundamental logical calculations. But a three-qubit system is the minimum unit for scaling up and implementing error correction.

The process involved entangling two qubits to begin with, in what's known as a two-qubit gate – a standard building block of quantum computers. That gate was then combined with a third qubit with an impressively high fidelity of 88 percent (a measure of how reliable the system is).

Each of the quantum silicon dots holds a single electron, with its spin-up and spin-down states doing the encoding. The setup also included an integrated magnet, enabling each qubit to be controlled separately using a magnetic field.

The researchers think there's plenty more to come from quantum silicon dots linking together more and more qubits in the same circuit. Full-scale quantum computers could be closer than we think.

https://www.nature.com/articles/s41565-021-00925-0

https://www.sciencealert.com/scientists-have-entangled-three-qubits...

Why Nearly 80 Percent of Autoimmune Sufferers Are Female

The effects of sex hormones, X chromosomes and different gut microbes may be parts of the answer.

Burning space mystery solved as researchers confirm origins of 'empty sky' gamma-rays

Star-forming galaxies are responsible for creating gamma-rays that until now had not been associated with a known origin, researchers have confirmed.

Until now it has been unclear what created gamma-rays—one of the most energetic forms of light in the Universe—that appear in patches of seemingly "empty sky."

The discovery could offer clues to help astronomers solve other mysteries of the Universe, such as what kind of particles make up Dark Matter—one of the holy grails of astrophysics.

"It's a significant milestone to finally discover the origins of this gamma-ray emission, solving a mystery of the Universe astronomers have been trying to decipher since the 1960s.

There are two obvious sources that produce large amounts of gamma-rays seen in the Universe. One when gas falls into the supermassive black holes which are found at the centers of all galaxies—called an active galactic nucleus (AGN)—and the other associated with star formation in the disks of galaxies.

Researchers modeled the gamma-ray emission from all the galaxies in the Universe and compared our results with the predictions for other sources and found that it is star-forming galaxies that produce the majority of this diffuse gamma-ray radiation and not the AGN process.

researchers were able to pinpoint what created these mysterious gamma-rays after obtaining a better understanding of how cosmic rays—particles that travel at speeds very close to the speed of light—move through the gas between the stars. Cosmic rays are important because they create large amounts of gamma-ray emission in star-forming galaxies when they collide with the interstellar gas.

Matt A. Roth et al, The diffuse γ-ray background is dominated by star-forming galaxies, Nature (2021). DOI: 10.1038/s41586-021-03802-x Matt A. Roth et al, The diffuse γ-ray background is dominated by star-forming galaxies, Nature (2021). DOI: 10.1038/s41586-021-03802-x

https://phys.org/news/2021-09-space-mystery-sky-gamma-rays.html?utm...

Researchers infuse bacteria with silver to improve power efficiency in fuel cells

A team of engineers and chemists has taken a major step forward in the development of microbial fuel cells—a technology that utilizes natural bacteria to extract electrons from organic matter in wastewater to generate electrical currents. A study detailing the breakthrough was recently published in Science. 

Living energy-recovery systems utilizing bacteria found in wastewater offer a one-two punch for environmental sustainability efforts. The natural populations of bacteria can help decontaminate groundwater by breaking down harmful chemical compounds. Now, research also shows a practical way to harness renewable energy from this process.

The team focused on the bacteria genus Shewanella, which have been widely studied for their energy-generation capabilities. They can grow and thrive in all types of environments—including soil, wastewater and seawater—regardless of oxygen levels.  

Shewanella species naturally break down organic waste matter into smaller molecules, with electrons being a byproduct of the metabolic process. When the bacteria grow as films on electrodes, some of the electrons can be captured, forming a microbial fuel cell that produces electricity. 

However, microbial fuel cells powered by Shewanella oneidensis have previously not captured enough currents from the bacteria to make the technology practical for industrial use. Few electrons could move quickly enough to escape the bacteria's membranes and enter the electrodes to provide sufficient electrical currents and power.

To address this issue, the researchers added nanoparticles of silver to electrodes that are composed of a type of graphene oxide. The nanoparticles release silver ions, which bacteria reduce to silver nanoparticles using electrons generated from their metabolic process and then incorporate into their cells. Once inside the bacteria, the silver particles act as microscopic transmission wires, capturing more electrons produced by the bacteria.

With greatly improved electron transport efficiency, the resulting silver-infused Shewanella film outputs more than 80% of the metabolic electrons to external circuit, generating a power of 0.66 milliwatts per square centimeter—more than double the previous best for microbial-based fuel cells.

Silver nanoparticles boost charge extraction efficiency in Shewanella microbial fuel cells, Science (2021). DOI: 10.1126/science.abf3427

https://phys.org/news/2021-09-infuse-bacteria-silver-power-efficien...

New technology makes it possible to see clearly through murky water

Researchers have developed a new method that can automatically produce clear images through murky water. The new technology could be useful for searching for drowning victims, documenting submerged archaeological artifacts and monitoring underwater farms.

Imaging clearly underwater is extremely challenging because the water and the particles in it tend to scatter light. But, because scattered light is partially polarized, imaging using a camera that is sensitive to polarization can be used to suppress scattered light in underwater images.

A  new method overcomes the limitations of traditional polarimetric underwater imaging, laying the groundwork for taking this method out of the lab and into the field.

Traditional approaches to underwater imaging use either prior knowledge of the imaging area or the background of an image to calculate and remove scattered light. These methods have limited utility in the field because they typically require manual processing, images do not always have visible backgrounds, and prior information is not always available.

To overcome these challenges, the researchers combined a traditional polarized imaging setup with a new algorithm that automatically finds the optimal parameters to suppress the scattering light. This not only significantly improves image contrast to achieve clear imaging but can be used without any prior knowledge of the imaging area and for images with or without background regions.

Hongyuan Wang et al, Automatic underwater polarization imaging without background region or any prior, Optics Express (2021). DOI: 10.1364/OE.434398

https://phys.org/news/2021-09-technology-murky.html?utm_source=nwle...

Part of the universe's missing matter found

Galaxies can receive and exchange matter with their external environment thanks to the galactic winds created by stellar explosions. Via the MUSE instrument from the Very Large Telescope at the ESO, an international research team, led on the French side by the CNRS and l'Université Claude Bernard Lyon 1, has mapped a galactic wind for the first time. This unique observation, which is detailed in a study published in MNRAS on 16 September 2021, helped to reveal where some of the universe's missing matter is located and to observe the formation of a nebula around a galaxy.

Galaxies are like islands of stars in the universe, and possess ordinary, or baryonic, matter, which consists of elements from the periodic table, as well as dark matter, whose composition remains unknown. One of the major problems in understanding the formation of galaxies is that approximately 80% of the baryons that make up the normal matter of galaxies is missing. According to models, they were expelled from galaxies into inter-galactic space by the galactic winds created by stellar explosions.

An international team led on the French side by researchers from the CNRS and l'Université Claude Bernard Lyon successfully used the MUSE instrument to generate a detailed map of the galactic wind driving exchanges between a young galaxy in formation and a nebula (a cloud of gas and interstellar dust).

The perfect positioning of the galaxy and the quasar, as well as the discovery of gas exchange due to galactic winds, made it possible to draw up a unique map. This enabled the first observation of a nebula in formation that is simultaneously emitting and absorbing magnesium—some of the universe's missing baryons—with the Gal1 galaxy.

This type of normal matter nebula is known in the near universe, but their existence for young galaxies in formation had only been supposed.

Scientists thus discovered some of the universe's missing baryons, thereby confirming that 80–90% of normal matter is located outside of galaxies, an observation that will help expand models for the evolution of galaxies.

 Johannes Zabl et al, MusE GAs FLOw and Wind (MEGAFLOW) VIII. Discovery of a Mgii emission halo probed by a quasar sightline, Monthly Notices of the Royal Astronomical Society (2021). DOI: 10.1093/mnras/stab2165

https://phys.org/news/2021-09-universe.html?utm_source=nwletter&...

Did the coronavirus jump from animals to people twice?

Fine-tooth comb

They analysed 1,716 SARS-CoV-2 genomes in a popular online genome repository called GISAID that were collected before 28 February 2020, and identified 38 such ‘intermediate’ genomes.

But when they looked at the sequences more closely, they found that many of these also contained mutations in other regions of their genomes. And they say that these mutations are definitively associated with either lineage A or lineage B — which discredits the idea that the corresponding viral genomes date to an intermediate stage of evolution between the two lineages.

The authors suggest that a laboratory or computer error probably occurred in sequencing one of the two mutations in these ‘intermediate’ genomes. “The more we dug, the more it looked like, maybe we can’t trust any of the ‘transitional’ genomes,” says study co-author Michael Worobey, an evolutionary biologist at the University of Arizona in Tucson.

Such sequencing errors are not unusual, say researchers. Software can sometimes fill in gaps in the raw data with incorrect sequences, and viral samples can become contaminated, notes Richard Neher, a computational biologist at the University of Basel in Switzerland. “Such mishaps are not surprising,” he says. “Especially early in the pandemic, when protocols weren’t very established and people tried to generate data as fast as they could.”

Several researchers contacted by Nature, who sequenced some of the samples included in the study, say it is unlikely that their sequences include errors in the two key nucleotides.

But the study authors counter that even if some of the genomes were sequenced correctly, other parts of the same genomes, or the locations from which the samples were collected, still clearly indicate that they belong to only one or the other lineage.

“It is very unlikely” that any of the so-called intermediate genomes are actually transitional genomes, says study co-author

part2

doi: https://doi.org/10.1038/d41586-021-02519-1

part 3

References

Ebola virus in survivors can trigger outbreaks years after infection

Ebola survivors can relapse and trigger outbreaks at least five years after infection, and long-term follow-up of former patients is needed to prevent devastating flare-ups, according to new research.

Scientists already knew Ebola could lie dormant in survivors, who test negative because the virus is in tissue rather than circulating in the blood.

But analysis of an outbreak this year in Guinea, published Wednesday in the journal Nature, found these "virus reservoirs" can awaken and cause new infections and transmission years on.

To trace the source of the Guinea outbreak, which involved 16 confirmed cases, 12 of whom died, researchers analysed the genomes of samples from several patients.

Ebola outbreaks are usually thought to result from the virus "spilling" from an animal host to a human.

But the analysis showed the Guinea strain was virtually identical to that from a 2013-16 wave.

If the virus had been circulating actively in the community since then, it would have accumulated a certain number of mutations as it spread.

Instead, the 2021 virus had just 12 changes, "far fewer than would be expected... during six years of sustained human-to-human transmission".

That strongly suggests the source was reactivated virus that had lain dormant in a survivor.

This is the longest known time between the declared end of an epidemic and a viral resurgence.

How and why dormant Ebola virus suddenly awakens and sickens a person remains something of a mystery, though there are some tantalising clues.

Sometimes a spike in Ebola antibodies can be detected in survivors at a given time -- a possible sign that the body is responding to a resurgent virus.

Around two-thirds of Ebola survivors have high antibody levels even five years after infection, but "the question to pose is what happens if there's a resurgence in the people whose immunity has dropped.

https://www.nature.com/articles/d41586-021-02378-w

source: Agence France-Presse

https://researchnews.cc/news/8930/Ebola-virus-in-survivors-can-trig...

The microbial molecule that turns plants into zombies

A newly discovered manipulation mechanism used by parasitic bacteria to slow down plant aging, may offer new ways to protect disease-threatened food crops.

Parasites manipulate the organisms they live off to suit their needs, sometimes in drastic ways. When under the spell of a parasite, some plants undergo such extensive changes that they are described as "zombies". They stop reproducing and serve only as a habitat and host for the parasitic pathogens.

Until now, there's been little understanding of how this happens on a molecular and mechanistic level.

Research from the Hogenhout group at the John Innes Centre and collaborators published in Cell, has identified a manipulation molecule produced by Phytoplasma bacteria to hijack plant development. When inside a plant, this protein causes key growth regulators to be broken down, triggering abnormal growth.

Phytoplasma bacteria belong to a group of microbes that are notorious for their ability to reprogramme the development of their host plants. This group of bacteria are often responsible for the 'witches' brooms' seen in trees, where an excessive number of branches grow close together.

These bushy outgrowths are the result of the plant being stuck in a vegetative "zombie" state, unable to reproduce and therefore progress to a 'forever young' status. Phytoplasmas are a spectacular example of how the reach of genes can extend beyond the organisms to impact surrounding environments.

The new findings show how the bacterial protein  known as SAP05 manipulates plants by taking advantage of some of the host's own molecular machinery.

This machinery, called the proteasome, usually breaks down proteins that are no longer needed inside plant cells. SAP05 hijacks this process, causing plant proteins that are important in regulating growth and development, to effectively be thrown in a molecular recycling centre.

Without these proteins, the plant's development is reprogrammed to favour the bacteria, triggering the growth of multiple vegetative shoots and tissues and putting the pause on the plant ageing.

Parasitic modulation of host development by ubiquitin-independent protein degradation, Cell www.cell.com/cell/fulltext/S0092-8674(21)01012-6. DOI: 10.1016/j.cell.2021.08.029

https://phys.org/news/2021-09-microbial-molecule-zombies.html?utm_s...

How do cells acquire their shapes?

 A new mechanism that a simple yeast cell uses to acquire its shape has been identified recently by researchers. 

When cells move or grow, they must add new membrane to those growth regions.

The process of membrane delivery is called exocytosis. Cells also must deliver this membrane to a specific location in order to maintain a sense of direction―called "polarization"―or grow in a coordinated manner.

Researchers have demonstrated that these processes are coupled: local excess of exocytosis causes some of the proteins attached to the membrane to move ('flow') away from the growth region. These proteins that move away mark the non-growing cell region, thus establishing a self-sustaining pattern, which gives rise to the tubular shape of these yeast cells. 

This is the first time that this mechanism for cell patterning―the process by which cells acquire spatial nonuniformities on their surfaces―has been identified.

 Cell patterning by secretion-induced plasma membrane flows, Science Advances (2021). DOI: 10.1126/sciadv.abg6718

https://phys.org/news/2021-09-cells-mechanism.html?utm_source=nwlet...

How to make dormant seeds to germinate

Seeds that would otherwise lie dormant will spring to life with the aid of a new chemical discovered by researchers. 

Plants have the ability to perceive drought. When they do, they emit a hormone that helps them hold on to water. This same hormone, ABA, sends a message to seeds that it isn't a good time to germinate, leading to lower crop yields and less food in places where it's hot—an increasingly long list as a result of climate change.

"If you block ABA, you mess with the chemical pathway that plants use to prevent seed germination. A new chemical, Antabactin, does exactly this. If we apply it,  dormant seeds will sprout.

Demonstrations of Antabactin's effectiveness are described in a new paper published in the Proceedings of the National Academy of Sciences.

Aditya S. Vaidya et al, Click-to-lead design of a picomolar ABA receptor antagonist with potent activity in vivo, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2108281118

https://phys.org/news/2021-09-chemical-discovery-reluctant-seeds.ht...

Mass extinction: A warning that this can happen now too

The end-Permian mass extinction event of roughly 252 million years ago—the worst such event in earth's history—has been linked to vast volcanic emissions of greenhouse gases, a major temperature increase, and the loss of almost every species in the oceans and on land.

Now, it seems that even the lakes and rivers were no safe havens. A recent study published by an international team of researchers  has identified a new cause of extinction during extreme warming events: toxic microbial blooms.

In a healthy ecosystem, microscopic algae and cyanobacteria provide oxygen to aquatic animals as a waste product of their photosynthesis. But when their numbers get out of control, these microbes deplete free oxygen, and even release toxins into the water. By studying the fossil, sediment, and chemical records of rocks near Sydney, Australia, the researchers discovered that several pulses of bloom events had occurred soon after the first volcanic rumblings of the end-Permian mass extinction. Once the bottom-feeder animals, or "detritivores," were killed off, there was no one left to keep the microbes in check. The fresh water systems then seethed with algae and bacteria, delaying the recovery of animals for perhaps millions of years.

We're seeing more and more toxic algae blooms in lakes and in shallow marine environments that's related to increases in temperature and changes in plant communities which are leading to increases in nutrient contributions to freshwater environments. So, a lot of parallels to today. The volcanism was a source of CO₂ in the past but we know that the rate of CO₂ input that was seen back then was similar to the rate of CO₂ increases we're seeing today because of anthropogenic effects.

We can get a sense of how much climate has changed in the past, what the extremes are, how fast it can change, what the causes of climate change are and that gives us a nice backdrop for understanding what's happening today. The end-Permian is one of the best places to look for parallels with what's happening now.

The other big parallel is that the increase in temperature at the end of the Permian coincided with massive increases in forest fires. One of the things that that destroyed whole ecosystems was fire, and we're seeing that right now in several  places .

We should be concerned like hell!

Chris Mays et al, Lethal microbial blooms delayed freshwater ecosystem recovery following the end-Permian extinction, Nature Communications (2021). DOI: 10.1038/s41467-021-25711-3

https://phys.org/news/2021-09-animals-died-toxic-soup-earth.html?ut...

Do the northern lights make sounds that you can hear?

https://theconversation.com/do-the-northern-lights-make-sounds-that...

Antibodies from original strain COVID-19 infection don't bind to variants, study finds

People infected with the original strain of the virus that causes COVID-19 early in the pandemic produced a consistent antibody response, making two main groups of antibodies to bind to the spike protein on the virus’s outer surface. However, those antibodies don’t bind well to newer variants, a new study found.

Researchers found that many antibody sequences converged into two main groups, indicating a consistent human immune response to the virus. The researchers studied the convergent antibodies’ ability to bind to several variants and found that they no longer bound to some. The finding has implications for the ability of new variants to reinfect people who contracted earlier versions of the virus, as well as for the continuing efficacy of vaccines and the design of possible vaccine boosters.

Even though this antibody response is very common with the original strain, it doesn’t really interact with variants. That, of course, raises the concern of the virus evolving to escape the body’s main antibody response. Some antibodies should still be effective – the body makes antibodies to many parts of the virus, not only the spike protein – but the particular groups of antibodies that we saw in this study will not be as effective.

The researchers said they would like to conduct similar studies characterizing antibody responses to delta and other variants, to see whether they also produce a convergent response and how it differs from the original strain. 

It is expected that the antibody response to those variants would be quite different. 

https://www.nature.com/articles/s41467-021-24123-7'

https://news.illinois.edu/view/6367/1126344363

https://researchnews.cc/news/8965/Antibodies-from-original-strain-C...

Will Indian researchers lose free access to scientific papers?

It’ll depend on the outcome of an ongoing case against SciHub and LibGen websites in the Delhi High Court.

On December 21, 2020, academic publishers Elsevier Ltd, Wily Pvt Ltd, and the American Chemical Society sued websites SciHub and Library Genesis, also known as LibGen, for copyright infringement in the Delhi High Court, demanding that ISP providers permanently block them in India.

These websites are a primary source for researchers in India, making available for free thousands of otherwise paywalled research papers. Because, as SciHub notes, “Research should be free to read.” Having intellectual property restrictions in research throttle access to and flow of knowledge while science can only progress when it’s widely read and debated.

Elsevier owns over 2,600 journals, including the Lancet, and all of them are paywalled with subscription rates going up to thousands of dollars, making the latest knowledge hard to access for researchers.

part 1

https://www.newslaundry.com/2021/09/18/will-indian-researchers-lose...

The Future of Wearable Tech

Engineers create light-emitting plants that can be charged repeatedly

Using specialized nanoparticles embedded in plant leaves, MIT engineers have created a light-emitting plant that can be charged by an LED. After 10 seconds of charging, plants glow brightly for several minutes, and they can be recharged repeatedly.

These plants can produce light that is 10 times brighter than the first generation of glowing plants that the research group reported in 2017.

Creating ambient light with the renewable chemical energy of living plants is a bold idea. It represents a fundamental shift in how we think about living plants and electrical energy for lighting.

The particles can also boost the light production of any other type of light-emitting plant, including those the researchers originally developed. Those plants use nanoparticles containing the enzyme luciferase, which is found in fireflies, to produce light. The ability to mix and match functional nanoparticles inserted into a living plant to produce new functional properties is an example of the emerging field of "plant nanobionics."

Their  first generation of light-emitting plants contained nanoparticles that carry luciferase and luciferin, which work together to give fireflies their glow. Using these particles, the researchers generated watercress plants that could emit dim light, about one-thousandth the amount needed to read by, for a few hours.

In the new study, Strano and his colleagues wanted to create components that could extend the duration of the light and make it brighter. They came up with the idea of using a capacitor, which is a part of an electrical circuit that can store electricity and release it when needed. In the case of glowing plants, a light capacitor can be used to store light in the form of photons, then gradually release it over time.

To create their "light capacitor," the researchers decided to use a type of material known as a phosphor. These materials can absorb either visible or ultraviolet light and then slowly release it as a phosphorescent glow. The researchers used a compound called strontium aluminate, which can be formed into nanoparticles, as their phosphor. Before embedding them in plants, the researchers coated the particles in silica, which protects the plant from damage.

The particles, which are several hundred nanometers in diameter, can be infused into the plants through the stomata—small pores located on the surfaces of leaves. The particles accumulate in a spongy layer called the mesophyll, where they form a thin film. A major conclusion of the new study is that the mesophyll of a living plant can be made to display these photonic particles without hurting the plant or sacrificing lighting properties, the researchers say.

This film can absorb photons either from sunlight or an LED. The researchers showed that after 10 seconds of blue LED exposure, their plants could emit light for about an hour. The light was brightest for the first five minutes and then gradually diminished. The plants can be continually recharged for at least two weeks.

Pavlo Gordiichuk et al, Augmenting the living plant mesophyll into a photonic capacitor, Science Advances (2021). DOI: 10.1126/sciadv.abe9733

https://phys.org/news/2021-09-light-emitting-repeatedly.html?utm_so...

Nano-scale discovery could help to cool down overheating in electronics

A team of physicists  solved the mystery behind a perplexing phenomenon in the nano realm: why some ultra-small heat sources cool down faster if you pack them closer together. The findings  could one day help the tech industry design faster electronic devices that overheat less.

Often, heat is a challenging consideration in designing electronics. You build a device then discover that it's heating up faster than desired.

In 2015, physicists  were experimenting with bars of metal that were many times thinner than the width of a human hair on a silicon base. When they heated those bars up with a laser, something strange occurred.

They behaved very counterintuitively. These nano-scale heat sources do not usually dissipate heat efficiently. But if you pack them close together, they cool down much more quickly.

Now, the researchers know why it happens.

In the new study, they used computer-based simulations to track the passage of heat from their nano-sized bars. They discovered that when they placed the heat sources close together, the vibrations of energy they produced began to bounce off each other, scattering heat away and cooling the bars down.

The group's results highlight a major challenge in designing the next generation of tiny devices, such as microprocessors or quantum computer chips: When you shrink down to very small scales, heat does not always behave the way you think it should.

 Directional thermal channeling: A phenomenon triggered by tight packing of heat sources, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2109056118

https://phys.org/news/2021-09-nano-scale-discovery-cool-overheating...

Yeast and bacteria together biosynthesize plant hormones for weed control

Plants regulate their growth and development using hormones, including a group called strigolactones that prevent excessive budding and branching. For the first time, scientists  have synthesized strigolactones from microbes.

Strigolactones also help plant roots form symbiotic relationships with microorganisms that allow the plant to absorb nutrients from the soil. These two factors have led to agricultural interest in using strigolactones to control the growth of weeds and root parasites, as well as improving nutrient uptake.

These root-extruding compounds don't come without risks. They also stimulate germination of witchweeds and broomrapes, which can cause entire crops of grain to fail, making thorough research essential prior to commercial development. Scientists are still learning about the physiological roles played by this diverse group of hormones in plants. Until recently, manufacturing pure strigolactones for scientific study has been difficult and too costly for agricultural use.

The new  work provides a unique platform to investigate strigolactone biosynthesis and evolution, and it lays the foundation for developing strigolactone microbial bioproduction processes as alternative sourcing.

Researchers directed a group that inserted plant genes associated with strigolactone production into ordinary baker's yeast and nonpathogenic Escherichia coli bacteria that together produced a range of strigolactones.

Sheng Wu et al, Establishment of strigolactone-producing bacterium-yeast consortium, Science Advances (2021). DOI: 10.1126/sciadv.abh4048

https://phys.org/news/2021-09-yeast-bacteria-biosynthesize-hormones...

**

Science of Concrete & the Surfside Condo Collapse

The Placebo Effect Is an Amazing Illusion, But That Doesn't Mean It's Medicine

Placebo is a beneficial effect produced by a placebo drug or treatment, which cannot be attributed to the properties of the placebo itself, and must therefore be due to the patient's belief in that treatment.

The placebo is one of science's greatest mysteries. The pill that isn't a pill. The medical illusion that somehow becomes real.

The mind-boggling weirdness of the placebo effect is certainly a strange thing, nobody doubts that.

But just because the placebo effect occasionally delivers unexpected outcomes doesn't mean we should overestimate how powerful it is – nor try to find a place for it in the medical care of patients, scientists are now warning.

In a new perspective article, researchers argue that recent suggestions placebos could play a role in clinical care are unfounded, and are based on flawed evidence.

Much of the current discourse on placebo seems to focus more on enshrining placebos as mysterious and highly effective and less on making a practical difference to patient care and outcomes.

Observations of the placebo effect can be traced back to the 18th century, and the reputation of the placebo has grown ever since: the idea that an inert, sham treatment, taken unknowingly by a patient, can sometimes deliver therapeutic effects like the real thing.

That reputation is mostly underserved. A Cochrane review of placebos considered 234 trials and concluded that, in general, placebos do not produce major health benefits, except for some small and inconsistent effects on self-reported outcomes such as pain or nausea," the researchers explain.

Placebos remain important for clinical trials because they help achieve blinding and, thus, control of bias," the team writes.

"When administered in a blinded fashion, a placebo will provide a small effect, but the real treatment will normally provide better outcomes for the patient… It may be better to dismiss placebos and instead manage patients with evidence-based treatments., they conclude.

https://onlinelibrary.wiley.com/doi/10.5694/mja2.51230

https://www.sciencealert.com/the-placebo-effect-is-an-amazing-illus...

Serious Infections Linked to Autism: Study

In both a mouse model and the hospital records of more than 3 million children, researchers found a connection between strong immune activation in males and later symptoms of autism spectrum disorder.

While researchers have found plenty of gene variants that seem to increase the risk of an autism diagnosis, it’s not clear why some people carrying these mutations develop autism spectrum disorders and some do not. In a study published today (September 17) in Science Advances, researchers point to a potential answer: severe infections during early childhood. After an early immune challenge, male mice with a mutated copy of the tuberous sclerosis complex 2 (Tsc2) gene developed deficits in social behavior linked to changes in microglia, the immune cells of the brain. And an analysis of the hospital records of more than 3 million children showed that children, particularly boys, who were hospitalized for infections between ages 18 months and four years were more likely that healthy peers to receive a future autism spectrum disorder (ASD) diagnosis.

https://www.science.org/doi/10.1126/sciadv.abf2073

https://www.the-scientist.com/news-opinion/serious-infections-linke...

Inhibiting targets of SARS-CoV-2 proteases can block infection, study shows

Researchers  have shown how SARS-CoV-2 viral proteases attack the host cell, and how this can be targeted to stop virus replication in cell culture using existing drugs.

The new findings, published today in Nature Communications, offer a powerful resource to understand proteolysis in the context of viral infection, and to inform the development of targeted strategies to inhibit the virus that causes COVID-19.

Both viral and cellular proteases play a crucial role in SARS-CoV-2 replication, and inhibitors targeting proteases have already shown success at inhibiting SARS-CoV-2 in cell culture models. 

In this study, researchers used a mass spectrometry approach to study proteolytic cleavage events during SARS-CoV-2 infection.

The team found previously unknown cleavage sites in multiple viral proteins, including major antigenic proteins S and N, which are the main targets for vaccine and antibody testing efforts.

They discovered significant increases in cellular cleavage events consistent with cleavage by SARS-CoV-2 main protease (Mpro) and identified 14 potential high-confidence substrates of the main and papain-like proteases, validating a subset with in vitro assays.

They went on to show that siRNA depletion of these cellular proteins inhibits SARS-CoV-2 replication, and that drugs targeting two of these proteins: the tyrosine kinase SRC and Ser/Thr kinase MYLK, showed a dose-dependent reduction in SARS CoV-2 titres.

Both Bafetinib (an experimental cancer drug) and Sorafenib (an approved drug used to treat kidney and liver cancer) showed SARS-CoV-2 inhibition at concentrations that did not result in cytotoxicity in a human cell line model of infection.

Characterising proteolysis during SARS-CoV-2 infection identifies viral cleavage sites and cellular targets with therapeutic potential, Nature Communications (2021). DOI: 10.1038/s41467-021-25796-w

https://phys.org/news/2021-09-inhibiting-sars-cov-proteases-block-i...

Rock shape should be given greater consideration in rockfall risk assessments

The shape of rocks is a key factor in assessing rockfall hazard. This is the conclusion of a new study from the Institute for Snow and Avalanche Research.

Rockfall is a very real threat in an Alpine country like Switzerland. In order to assess the hazard at a given location and plan protective measures, engineering firms use computer models to calculate how far falling rocks can roll. However, the models are not yet able to adequately take into account the extent to which the mass, size or shape of a rock influences its movement. This would require real-world measurement data to be fed into the models, but until now such data were only available sporadically, since no systematic rockfall studies had been conducted.

First comprehensive experiments

That has now changed after researchers  spent over four years carrying out rockfall experiments. This has allowed them to compile the largest set of measurement data to date.

The researchers used artificial rocks in the form of concrete blocks fitted with sensors, which they rolled down a slope near the Flüela Pass in the Swiss canton of Grisons. They compared different shapes and masses, reconstructed the complete trajectories and determined speeds, jump heights and runout zones (see info box). They have just published their results in the scientific journal Nature Communications.

The most significant finding is that the direction a rock rolls in depends much more on its shape than on its mass. While cube-shaped boulders plunge straight down the line of greatest slope, wheel-shaped rocks often pull away to one side and so may threaten a much wider area at the base of the slope. "This needs to be taken into consideration when assessing danger zones, but also when determining the location and dimensions of rockfall nets.

Because wheel-like rocks hit rockfall nets with their narrow side, their energy is concentrated on a much smaller area than is the case with cube-like rocks—so protective nets need to be stronger.

The data set is also available on the EnviDat platform, where it is freely accessible to other research groups. They can use it to calibrate their own algorithms or to develop new, more accurate models providing enhanced protection against rockfall.

Andrin Caviezel et al, The relevance of rock shape over mass—implications for rockfall hazard assessments, Nature Communications (2021). DOI: 10.1038/s41467-021-25794-y

https://phys.org/news/2021-09-greater-consideration-rockfall.html?u...

Satellite swarms may outshine the night sky’s natural constellations

“Mega-constellations” from those satellites will be visible to the naked eye, simulations suggest

A few years back  somebody asked me from the art field, "If You 're asked to make a science-art installation, what would it be?" My instant answer was, "Groups of satellites in the night sky that shine like star constellations and also help the mankind". 

"Wow!" was that person's reaction.

But,  now that reply of mine is going to be revisited. Why? Companies like SpaceX and Amazon have launched hundreds of satellites into low orbits since 2019, with plans to launch thousands more in the works — a trend that’s alarming astronomers. The goal of these satellite “mega-constellations” is to bring high-speed internet around the globe, but these bright objects threaten to disrupt astronomers’ ability to observe the cosmos.

 Now, a new simulation of the potential positions and brightness of these satellites shows that, contrary to earlier predictions, casual sky watchers will have their view disrupted, too. And parts of the world will be affected more than others.

Flat, smooth surfaces on satellites can reflect sunlight depending on their position in the sky. Earlier research had suggested that most of the new satellites would not be visible with the naked eye.

There are currently about 7,890 objects in Earth orbit, about half of which are operational satellites, according to the U.N. Office for Outer Space Affairs. But that number is increasing fast as companies launch more and more satellites . In August 2020, there were only about 2,890 operational satellites.

Part1

the researchers computed how many satellites will be in the sky at different times of year, at different hours of the night and from different positions on Earth’s surface. They also estimated how bright the satellites were likely to be at different hours of the day and times of the year.

The simulations showed that “the way the night sky is going to change will not affect all places equally,” Lawler says. The places where naked-eye stargazing will be most affected are at latitudes 50° N and 50° S, regions that cross lower Canada, much of Europe, Kazakhstan and Mongolia, and the southern tips of Chile and Argentina, the researchers found.

The geometry of sunlight in the summer means there will be hundreds of visible satellites all night long. It’s bad everywhere, but it’s worse there.

--

A few visible satellites can be a fun spectacle. Astronomers have been meeting with representatives from private companies, as well as space lawyers and government officials, to work out compromises and mitigation strategies. Companies have been testing ways to reduce reflectivity, like shading the satellites with a “visor.” Other proposed strategies include limiting the satellites to lower orbits, where they move faster across the sky and leave a fainter streak in telescope images. Counterintuitively, lower satellites may be better for some astronomy research. “They move out of the way quick.”

But that lower altitude strategy will mean more visible satellites for other parts of the world, and more that are visible to the naked eye.

There are some latitudes on Earth where no matter what altitude you put your satellites at, they’re going to be all over the darn place. The only way out of this is fewer satellites.

There are currently no regulations concerning how bright a satellite can be or how many satellites a private company can launch. Scientists are grateful that companies are willing to work with them, but think that their cooperation is voluntary. Efforts are under way to bring the issue to the attention of the United Nations and to try to use existing environmental regulations to place limits on satellite launches.

S. Lawler, A. Boley and H. Rein. Visibility predictions for near-future satellite megaconstellations.... arXiv:2109.04328. Posted September 9, 2021.

https://www.sciencenews.org/article/satellite-mega-constellations-n...

Salty Diet Helps Gut Bugs Fight Cancer in Mice: Study

Brain-Eating Amoeba