Bioengineers find new way heart valves grow – and go wrong

We're Doing Mindfulness Wrong, Psychologists Say

What does mindfulness mean to you? Is it about being aware of what comes your way without distraction? Or is it engaging with life's challenges without judgement, and responding as required?

A new meta-analysis of almost 150 studies has found that most of us understand that mindfulness is about both being aware and engaging with whatever comes our way. Unfortunately, we're much worse at putting this 'engaging' part into action.

Scientific understanding of mindfulness goes beyond mere stress-relief and requires a willingness to engage with stressors. It is, in fact, the engagement with stressors that ultimately results in stress relief. More specifically, mindfulness includes two main dimensions: awareness and acceptance.

Mindfulness derives from Buddhist traditions, and has become used in Western settings since the 1970s as part of psychiatry and psychology. It has been shown to help reduce depression, stress, anxiety, and even drug addiction, and is regularly recommended as a coping mechanism as part of therapy. 

In terms of regular people's understanding of mindfulness, we're really good at the 'awareness' part, the researchers say – where we take stock of what's around us, and any potential issues coming our way.

But the team found that we then tend to use mindfulness as a passive endorsement of the experience: the mindfulness equivalent of a shrug emoji. 

What we should do to get the full benefits of mindfulness is engage with our experiences, finding solutions and responses to our environment – something that the researchers found that we're aware of, but we just don't do.

"These modern applications of mindfulness have recently faced substantial criticism. Scholars suggest that popular definitions cast mindfulness as a 'quick fix' for suffering rather than a longitudinal practice of re-orienting, re-framing, and engaging with daily experience," the team writes in their paper.

Part 1

The team looked at 145 datasets, in total covering 41,966 participants who did the Five Facet Mindfulness Questionnaire. The five facets are observing, describing, acting with awareness, non-judging inner experience and non-reactivity to inner experience.

What the team found was that there was little 'convergence' across these facets across participants in non-clinical settings. Put simply, we're not embracing the whole package.

Researchers found that people seem to conceptually understand that mindfulness involves engagement, the general public is not walking the talk. Our results suggest that laypeople may understand what awareness is, but the next step of acceptance may not be well understood – limiting potential for engaging with problems.

https://www.sciencedirect.com/science/article/abs/pii/S027273582100...

Part 2

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Protein-based COVID vaccines

Some people can’t get current COVID-19 vaccines for health reasons, but protein-based vaccines offer hope that they might soon be immunized. To elicit a protective immune response, these shots deliver proteins, along with immunity-stimulating adjuvants, directly to a person’s cells, rather than sending in a fragment of genetic code that the cells must read to synthesize the proteins themselves. After months of quality-control setbacks and manufacturing delays, the protein-based jab from US biotechnology firm Novavax has just received its first emergency-use authorization, in Indonesia. Meanwhile, Clover Biopharmaceuticals, based in China, and Biological E in India are on track to file for authorization in various countries in the coming weeks and months.

https://mcusercontent.com/2c6057c528fdc6f73fa196d9d/images/eadad212..." alt="Protein vaccines 101: An infographic that shows how COVID-19 protein-based vaccines are made, and how the body reacts to them."/>

Giant Study Identifies The Best Time to Fall Asleep to Lower Risk of Heart Problems

While the link between sleep and a healthy heart is well established, researchers are still sussing out the details. A new study suggests there might even be an optimal time, within our 24-hour body clock, for falling asleep.

Of course, the reasons for not obtaining the right sleep, whether it's the best amount or right timing are not always within our control. So anyone struggling with their sleep should seek medical advice and focus on whatever they need to do that works for them – as dictating a specific bedtime may be counterproductive for some.

But for the rest of us it may be helpful to know that falling asleep between 10-11 pm seems to hit the sweet spot for a healthy cardiovascular system.

The body has a 24-hour internal clock, called circadian rhythm, that helps regulate physical and mental functioning. While we cannot conclude causation from our study, the results suggest that early or late bedtimes may be more likely to disrupt the body clock, with adverse consequences for cardiovascular health.

The team found falling asleep after midnight or before 10 pm both was associated with around a 25 percent increase in risk of cardiovascular disease, compared to falling asleep between 10-11 pm. This increase in risk dropped to 12 percent for those who fell asleep between 11-12 pm.

"The riskiest time was after midnight, potentially because it may reduce the likelihood of seeing morning light, which resets the body clock.

This trend remained when taking into account age, gender, sleep duration, being an early bird or night owl, smoking status, weight, diabetes, blood pressure, cholesterol level, and socioeconomic status. It was also more pronounced for women, but the researchers aren't yet sure why.

https://academic.oup.com/ehjdh/advance-article/doi/10.1093/ehjdh/zt...

https://www.sciencealert.com/huge-accelerometer-study-suggests-the-...

Sustainable, biodegradable, vegan glitter

Glitter is a bane of modern living. But beyond its general annoyance factor, it's also made of toxic and unsustainable materials, and contributes to plastic pollution.

Now, researchers from the University of Cambridge have found a way to make sustainable, non-toxic, vegan, and biodegradable glitter from cellulose—the main building block of cell walls in plants, fruits and vegetables—and that's just as sparkly as the original.

The glitter is made from cellulose nanocrystals, which can bend light in such a way to create vivid colors through a process called structural color. The same phenomenon produces some of the brightest colors in nature—such as those of butterfly wings and peacock feathers—and results in hues which do not fade, even after a century.

Using self-assembly techniques which allow the cellulose to produce intensely-colored films, the researchers say their materials could be used to replace the plastic glitter particles and tiny mineral effect pigments which are widely used in cosmetics.

The films of cellulose nanocrystals prepared by the team can be made at scale using roll-to-roll processes like those used to make paper from wood pulp, and this is the first time these materials have been fabricated at industrial scale. The results are reported in the journal Nature Materials.

Silvia Vignolini, Large-scale fabrication of structurally coloured cellulose nanocrystal films and effect pigments, Nature Materials (2021). DOI: 10.1038/s41563-021-01135-8. www.nature.com/articles/s41563-021-01135-8

https://phys.org/news/2021-11-sustainable-biodegradable-vegan-glitt...

'Dancing molecules' successfully repair severe spinal cord injuries in mice

Researchers have developed a new injectable therapy that harnesses "dancing molecules" to reverse paralysis and repair tissue after severe spinal cord injuries.

In a new study, researchers administered a single injection to tissues surrounding the spinal cords of paralyzed mice. Just four weeks later, the animals regained the ability to walk.

The research will be published in the Nov. 12 issue of the journal Science.

By sending bioactive signals to trigger cells to repair and regenerate, the breakthrough therapy dramatically improved severely injured spinal cords in five key ways: (1) The severed extensions of neurons, called axons, regenerated; (2) scar tissue, which can create a physical barrier to regeneration and repair, significantly diminished; (3) myelin, the insulating layer of axons that is important in transmitting electrical signals efficiently, reformed around cells; (4) functional blood vessels formed to deliver nutrients to cells at the injury site; and (5) more motor neurons survived.

After the therapy performs its function, the materials biodegrade into nutrients for the cells within 12 weeks and then completely disappear from the body without noticeable side effects. This is the first study in which researchers controlled the collective motion of molecules through changes in chemical structure to increase a therapeutic's efficacy.

The secret behind Stupp's new breakthrough therapeutic is tuning the motion of molecules, so they can find and properly engage constantly moving cellular receptors. Injected as a liquid, the therapy immediately gels into a complex network of nanofibers that mimic the extracellular matrix of the spinal cord. By matching the matrix's structure, mimicking the motion of biological molecules and incorporating signals for receptors, the synthetic materials are able to communicate with cells.

Part 1

Once connected to the receptors, the moving molecules trigger two cascading signals, both of which are critical to spinal cord repair. One signal prompts the long tails of neurons in the spinal cord, called axons, to regenerate. Similar to electrical cables, axons send signals between the brain and the rest of the body. Severing or damaging axons can result in the loss of feeling in the body or even paralysis. Repairing axons, on the other hand, increases communication between the body and brain.

The second signal helps neurons survive after injury because it causes other cell types to proliferate, promoting the regrowth of lost blood vessels that feed neurons and critical cells for tissue repair. The therapy also induces myelin to rebuild around axons and reduces glial scarring, which acts as a physical barrier that prevents the spinal cord from healing.

The signals used in the study mimic the natural proteins that are needed to induce the desired biological responses. While the new therapy could be used to prevent paralysis after major trauma (automobile accidents, falls, sports accidents and gunshot wounds) as well as from diseases, researchers think the underlying discovery—that "supramolecular motion" is a key factor in bioactivity—can be applied to other therapies and targets.

Zaida Alvarez et al, Bioactive Scaffolds with Enhanced Supramolecular Motion Promote Recovery from Spinal Cord Injury, Science (2021). DOI: 10.1126/science.abh3602. www.science.org/doi/10.1126/science.abh3602

https://medicalxpress.com/news/2021-11-molecules-successfully-sever...

Part 2

Scientists appeal for immediate climate action at COP26

More than 200 scientists told the COP26 summit Thursday to take immediate action to halt global warming, warning in an open letter that some climate change impacts were "irreversible" for generations.

The central task of the Glasgow meeting is to implement the Paris Agreement, with its goal of limiting temperature rise to between 1.5 and 2 degrees Celsius above pre-industrial levels.

But as negotiations enter their final days, commitments made so far could still lead to "catastrophic" warming of as much as 2.7C by 2100, according to the UN.

"We, climate scientists, stress that immediate, strong, rapid, sustained and large-scale actions are necessary," to keep warming within the Paris target, said the letter, signed by researchers across the world.

In August, a bombshell "code red" report from the world's top climate science body, the Intergovernmental Panel on Climate Change (IPCC), warned that Earth's average temperature will hit the 1.5C threshold around 2030, a decade earlier than projected only three years ago.

To keep from overshooting that temperature target the IPCC says emissions must fall 45 percent this decade.

Thursday's open letter, signed by some of the IPCC's report authors, calls on delegates in Glasgow to "fully acknowledge" the scientific evidence they have compiled of the severe threats posed by climate change.

"Cumulative greenhouse gas emissions to date already commit our planet to key changes of the climate system affecting human society and marine and terrestrial ecosystems, some of which are irreversible for generations to come," said the letter.

https://phys.org/news/2021-11-scientists-appeal-climate-action-cop2...

Second instance of canine coronavirus found in a person

 A University of Florida research team is helping to build the case that coronaviruses move between animals and people at a more frequent rate than previously understood. Earlier this year, the team reported the first known instance of a coronavirus common in pigs to have "spilled over" into people. Spillovers refer to events where a virus that is adapted to a certain kind of host—say, a dog, or pig—acquires features that allow it to infect an entirely different species of host, such as a person. In their newest work, the team retrospectively uncovered an instance where a coronavirus known from dogs, called a canine coronavirus, infected at least one person visiting Haiti in early 2017. The infected person had a mild illness with fever and fatigue. The new work published in Clinical Infectious Diseases on Oct. 28,2021. In an unusual twist, the virus was determined to closely match a canine coronavirus reported earlier in 2021.

Study Finds Fish Rubbing Up Against Their Predators — Sharks. Researchers suggest this behaviour plays a greater ecological role than previously known

There's a Strange Difference Between Human Brains And Those of Other Mammals

When it comes to the world of mammals, humans tend to stand out a fair bit.

While many animals share some aspects of our intelligence, they don't take it to the same level we have. But pinning down why we're more cognitively advanced on a neurological level has been tricky; to date, studies have found no significant differences between the brains of mammals. Now, we finally have a lead.

A team of researchers from the Massachusetts Institute of Technology (MIT) has found that, compared to other mammals, human brains have a much lower number of the neuronal channels that allow the flow of ions such as calcium, potassium, and sodium.

This flow produces the electrical impulses that allow neurons to communicate with each other; having fewer of them could mean that the human brain can operate more efficiently, diverting resources to more complex cognitive functions.

One of their findings concerned dendrites, the branching structures at the tips of nerve cells through which the brain's electrical impulses are received via ion channels. From here, the dendrite generates what we call an action potential, which transfers the signal onwards.

Part 1

When comparing the brains of the two species, the researchers found that the human dendrites had a marked lower density of these ion channels compared to rat dendrites. This was worth investigating further.

The new research has been expanded to include 10 species: shrew, mouse, gerbil, rat, ferret, guinea pig, rabbit, marmoset, macaque and, of course, human, using samples of tissue excised from epilepsy patients during brain surgery.

An analysis of the physical structure of these brains revealed that ion channel density increases with neuron size, with one notable exception: the human brain.

This, the researchers concluded, was to maintain ion channel density across a range of brain sizes; so, although the shrew had a higher number of neurons than the rabbit or the macaque in a given volume of brain, the density of ion channels in that volume was consistent.

"This building plan is consistent across nine different mammalian species. What it looks like the cortex is trying to do is keep the numbers of ion channels per unit volume the same across all the species. This means that for a given volume of cortex, the energetic cost is the same, at least for ion channels.

The exceptionally low ion channel density in the human brain was glaring, when compared with all the other brains.

All the comparison animals were significantly smaller than humans, of course, so it may be worth testing the samples of even larger animals. However, the macaque is often used in research as a model for the human brain.

The researchers suspect an evolutionary trade-off is possible for humans – this is when a biological system loses or diminishes a trait for an optimization elsewhere.

For example, it takes energy to pump ions through dendrites. By minimizing ion channel density, the human brain may have been able to deploy the energy savings elsewhere – perhaps in more complex synaptic connections, or more rapid action potentials.

"If the brain can save energy by reducing the density of ion channels, it can spend that energy on other neuronal or circuit processes

Part 2

Researchers think that humans have evolved out of this building plan that was previously restricting the size of cortex, and they figured out a way to become more energetically efficient, so you spend less ATP [energy molecules] per volume compared to other species."

This finding reveals, the researchers said, an intriguing avenue for further investigation. In future research, the team hopes to explore the evolutionary pressures that might have led to this difference, and isolate where, exactly, that extra brain energy is going.

The research has been published in Nature.

https://www.nature.com/articles/s41586-021-04072-3

https://www.sciencealert.com/we-ve-just-found-a-fascinating-differe...

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Part 3

The Matilda effect is a bias against acknowledging the achievements of those women scientists whose work is attributed to their male colleagues. This effect was first described by suffragist and abolitionist Matilda Joslyn Gage (1826–98) in her essay, "Woman as Inventor" (first published as a tract in 1870 and in the North American Review in 1883). The term "Matilda effect" was coined in 1993 by science historian Margaret W. Rossiter. Rossiter provides several examples of this effect. Trotula (Trota of Salerno), a 12th-century Italian woman physician, wrote books which, after her death, were attributed to male authors. Nineteenth- and twentieth-century cases illustrating the Matilda effect include those of Nettie Stevens, Lise Meitner, Marietta Blau, Rosalind Franklin, and Jocelyn Bell Burnell. The Matilda effect was compared to the Matthew effect, whereby an eminent scientist often gets more credit than a comparatively unknown researcher, even if their work is shared or similar.

https://en.wikipedia.org/wiki/Matilda_effect

Introduced birds are not replacing roles of human-caused extinct species: study

Human-caused bird extinctions are driving losses of functional diversity on islands worldwide, and the gaps they leave behind are not being filled by introduced (alien) species, finds a new study.

The study, published in Science Advances, shows how human impacts such as habitat destruction and climate change are impoverishing ecosystems, even on islands where alien birds actually outnumber the species that have gone extinct.

Humans have drastically changed bird communities, not only by driving animals to extinction but also by introducing species into new habitats across the globe. There has been some debate as to whether introduced species might replace the roles of the extinct species, thus maintaining functional diversity within the ecosystem; here, researchers found that is unfortunately not the case.

 Valuable functions that may be lost with bird extinctions can include pollination and seed dispersal, which can have cascading harmful effects on other species.

Some groups of birds have been particularly successful at establishing outside their natural areas—for example, many species of parrot and starling. Because of this, islands are becoming more homogeneous as the same kind of birds are established everywhere.

These new  findings add to evidence that conservation efforts should be focused on preserving functionally distinct threatened species, to stem the tide of harmful losses to biodiversity that are driven by human actions. Huge numbers of species are being driven to extinction by human-driven effects such as habitat loss and climate change, so it is vital that we act now to reduce our negative impact on global biodiversity.

 Ferran Sayol, Loss of functional diversity through anthropogenic extinctions of island birds is not offset by biotic invasions, Science Advances (2021). DOI: 10.1126/sciadv.abj5790. www.science.org/doi/10.1126/sciadv.abj5790

part 1

For this study, the researchers compiled an exhaustive list of all bird species that have been present in nine different archipelagos* before and after human-caused extinctions occurred. This covered 1,302 bird species, including 265 globally or locally extinct, and 355 established introductions from 143 separate species. In addition, the scientists visited different museum collections, including the Natural History Museum, to measure several morphological traits in skin or skeleton specimens. With this data, the researchers were able to quantify the trait diversity before and after bird extinctions, and identify the ecological niches extinct birds once filled.

The research team found that before human arrival, island bird communities were more morphologically diverse than they are today. Their findings show how human-driven extinctions have disproportionally affected some types of birds (for example, larger birds and flightless birds are more likely to go extinct), leading to the loss of certain ecological roles.

The researchers also found that different archipelagos are becoming more and more similar in terms of trait diversity as native birds go extinct and the same kind of alien species are being newly established in many places.

https://phys.org/news/2021-11-birds-roles-human-caused-extinct-spec...

Part 2

Researchers discover link between dietary fat and the spread of cancer

A new study uncovers how palmitic acid alters the cancer genome, increasing the likelihood the cancer will spread. Researchers have started developing therapies that interrupt this process and say a clinical trial could start in the next couple of years.
Metastasis—or the spread—of cancer remains the main cause of death in cancer patients and the vast majority of people with metastatic cancer can only be treated, but not cured. Fatty acids are the building blocks of fat in our body and the food we eat. Metastasis is promoted by fatty acids in our diet, but it has been unclear how this works and whether all fatty acids contribute to metastasis.
Newly published findings reveal that one such fatty acid commonly found in palm oil, called palmitic acid, promotes metastasis in oral carcinomas and melanoma skin cancer in mice. Other fatty acids called oleic acid and linoleic acid—omega-9 and omega-6 fats found in foods such as olive oil and flaxseeds—did not show the same effect. Neither of the fatty acids tested increased the risk of developing cancer in the first place.
The research found that when palmitic acid was supplemented into the diet of mice, it not only contributed to metastasis, but also exerts long-term effects on the genome. Cancer cells that had only been exposed to palmitic acid in the diet for a short period of time remained highly metastatic even when the palmitic acid had been removed from the diet.
The researchers discovered that this "memory" is caused by epigenetic changes—changes to how our genes function. The epigenetic changes alter the function of metastatic cancer cells and allow them to form a neural network around the tumor to communicate with cells in their immediate environment and to spread more easily. By understanding the nature of this communication, the researchers uncovered a way to block it and are now in the process of planning a clinical trial to stop metastasis in different types of cancer.

Salvador Benitah, Dietary palmitic acid promotes a prometastatic memory via Schwann cells, Nature (2021). DOI: 10.1038/s41586-021-04075-0. www.nature.com/articles/s41586-021-04075-0

https://researchnews.cc/news/9975/Researchers-discover-link-between...

New research helps explain the genetic basis for why we look the way we do

 Which genes control the defining features that make us look as we do? And how do they make it happen?

In 1990, University of California San Diego biologist William McGinnis conducted a seminal experiment that helped scientists unravel how high-level control genes called Hox genes shape our appearance features. The "McGinnis experiment" helped pave the way for understanding the role of Hox genes in determining the uniform appearances of species, from humans to chimpanzees to flies.

McGinnis, a professor emeritus of Cell and Developmental Biology and former dean of the Division of Biological Sciences, helped discover a defining DNA region that he termed the "homeobox," a sequence within genes that directs anatomical development. Since the now-famous McGinnis experiment, evolutionary and developmental biologists have pondered how these highly influential Hox genes determine the identities of different body regions.

More than three decades later, a study published in Science Advances and led by Ankush Auradkar, a UC San Diego postdoctoral scholar mentored by coauthor McGinnis and study senior author Ethan Bier, helps answer questions about how Hox genes function.

The now-textbook McGinnis experiment tested whether the proteins produced by a human or mouse Hox gene could function in flies. Following in these footsteps, the new study leveraged modern CRISPR gene editing to investigate whether all aspects of Hox gene function, which consists of both protein coding and control regions, could be replaced in a common laboratory fruit fly (Drosophila melanogaster) with its counterpart from a rarer Hawaiian cousin (Drosophila mimica), which has a very different face.

1. Ankush Auradkar, Emily A. Bulger, Sushil Devkota, William McGinnis, Ethan Bier. Dissecting the evolutionary role of the Hox gene proboscipedia in Drosophila mouthpart diversification by full locus replacement. Science Advances, 2021; 7 (46) DOI: 10.1126/sciadv.abk1003

Part 1

The gene in question, proboscipedia, would plainly reveal itself since it directs the formation of strikingly different mouth parts—smooth and spongy in D. mel but more grill-like (resembling the face of the alien in Predator science fiction films) in D. mim.

Study coauthor Emily Bulger first collected the notoriously difficult-to-breed D. mim samples from Hawai'i Volcanoes National Park, along with the only native fruit (Sapindus saponaria—Hawaiian soapberry) that the insects are known to eat, in order to establish a temporary colony in Bier's laboratory. Auradkar then collaborated with coauthor Sushil Devkota to decipher the genome sequence of the D. mim proboscipedia gene, which was nearly 44,000 bases long. The researchers then deleted the D. mel proboscipedia gene and replaced it with the D. mim version of the same.

As McGinnis had predicted, the new results revealed that the graceful facial structure of D. mel emerged as the "winner" over the rough features of D. mim. One trait of D. mim, however, did surface during the experiment: Sensory organs called maxillary palps that stick out from the face in D. mel instead ran parallel to feeding mouthparts as they do in D. mim. Auradkar used sophisticated genetic tools to determine the basis for this difference and tracked it down to a change in the pattern by which the proboscipedia gene is activated (control region changes).

The experiment's results help answer longstanding questions about whether Hox genes function as "master" regulatory genes that dictate different body parts in organisms. Or, as McGinnis proposed, whether Hox genes instead provide abstract positional codes and serve as scaffolds for downstream genes that best benefit the organism. Other than the maxillary palps, the new results demonstrated that McGinnis' scaffolding idea proved to be the case.

McGinnis says that beyond the implications for evolutionary biology, the results could help explain developmental issues rooted in fundamental human genetic processes.

"These fly studies provide a window into deep evolutionary time and inform us about the mechanisms by which body plans change during evolution," said Bier. "These insights may lead to a better of understanding of processes tied to congenital birth defects in humans. With the advent of powerful new CRISPR-based genome editing systems for human therapy on the horizon, new strategies might be formulated to mitigate some of the effects of these often debilitating conditions."

https://researchnews.cc/news/9981/New-research-helps-explain-the-ge...

part 2

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Achieving razor-sharp vision in the metaverse

Researchers may have unlocked function of mysterious structure found on neurons

 For 30 years, mysterious clusters of proteins found on the cell body of neurons in the hippocampus, a part of the brain, both intrigued and baffled James Trimmer.

Now, the distinguished professor of physiology and membrane biology at the UC Davis School of Medicine may finally have an answer. In a new study published in PNAS, Trimmer and his colleagues reveal these protein clusters are calcium signaling "hotspots" in the neuron that play a crucial role in activating gene transcription.

Transcription allows portions of the neuron's DNA to be "transcribed" into strands of RNA that are then used to create the proteins needed by the cell.

Structures found in many animals
Trimmer's lab studies the enigmatic clusters in mice, but they exist in invertebrates and all vertebrates—including humans. Trimmer estimates that there can be 50 to 100 of these large clusters on a single neuron.

He and his colleagues knew that the clusters are formed by a protein that passes potassium ions through membranes (a potassium channel). They also knew these clusters contain a particular type of calcium channel. Calcium channels allow calcium to enter cells, where it triggers a variety of physiological responses depending on the type of cell.

"The presence of these clusters in neurons is highly conserved," Trimmer said. Highly conserved features are relatively unchanged through evolutionary timescales, suggesting they have an important functional property in these very different types of animals.

The hippocampus, one region of the brain where the clusters are found on neurons, plays a major role in learning and memory. Researchers knew that disruption to these clusters—for example, from genetic mutations in the potassium channel—results in severe neurological disorders. But it was not clear why.

"We have known the function of other types of ion channel clusters, for example those at synapses, for a long time. However, there was no known role that these much larger structures on the cell body played in the physiology of the neuron," Trimmer said.

Experiment flooded calcium channels with 'decoys'
The experiment that revealed the function of the neuronal clusters was designed by Nicholas C. Vierra, a postdoctoral researcher in Trimmer's lab and lead author for the study.

"We developed an approach that let us uncouple the calcium channel from the potassium channel clusters in neurons. A key finding was that this treatment blocked calcium-triggered gene expression. This suggests that the calcium channel-potassium channel partnership at these clusters is important for neuronal function," Vierra said.

For their experiment, the researchers essentially "tricked" the calcium channels at these clusters by flooding the neurons with decoy potassium channel fragments. When the calcium channels grabbed onto the decoys instead of the real potassium channels, they fell away from the clusters.

As a result, the process known as excitation-transcription coupling, which links changes in neuronal electrical activity to changes in gene expression, was inactivated.

"There are a lot of different calcium channels, but the particular type of calcium channel found at these clusters is necessary for converting changes in electrical activity to changes in gene expression," Trimmer said. "We found that if you interfere with the calcium-signaling proteins located at these unusual clusters, you basically eliminate excitation-transcription coupling, which is critical for learning, memory, and other forms of neuronal plasticity."

Trimmer and Vierra hope their findings will open new avenues of research.

"A lot of research has focused on calcium signaling in dendrites—the sites where neurons receive signals from other neurons. Calcium signaling in the cell body of neurons has received less attention," said Vierra. "Now we understand much more about the significance of signaling at these specific sites on the cell body of the neuron."

"We are only at the beginning of understanding the significance of this signaling, but these new results may provide information that could shape new research into its role in brain function, and perhaps eventually into the development of new classes of therapeutics," said Trimmer.

Additional authors on the study include Samantha C. O'Dwyer, Collin Matsumoto and L. Fernando Santana, Department of Physiology and Membrane Biology, UC Davis School of Medicine.

https://researchnews.cc/news/9979/Researchers-may-have-unlocked-fun...

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Microbiomes: It's who you are that matters most

Every mammal hosts a hidden community of other organisms—the microbiome. Their intestines teem with complex microbial populations that are critical for nutrition, fighting disease and degrading harmful toxins. Throughout their lives, mammals are exposed to countless microbes through their food and environment, but only a small subset take up permanent residence in the host. Although scientists agree that diet, geography and evolutionary history structure the microbiome, the relative influence of each factor is a mystery. No rigorous study has investigated all three at once in wild mammal populations. Until now.

A team of University of Utah biologists analyzed the bacteria in the gut microbiome of woodrats (Neotoma species), a group of closely related herbivorous rodents abundant in the southwestern United States. The animals offered a unique opportunity to test how diet, geography and evolutionary history influence microbiome structure. The many woodrat species are morphologically similar, but populations live in a variety of habitats and have distinct diets. Woodrats are famous for eating extremely toxic plants and do so with support from specialized gut bacteria.

Woodrats are amazing—they have incredibly diverse diets. Individuals from the same species eat different foods at different locations, so it creates a natural experiment. It's hard to say what's driving their different microbiomes—is it what they're eating? Is it where they're living? Or is it who they are?

The researchers used DNA barcoding techniques to characterize the diet and gut bacteria of seven woodrat species from 25 populations at 19 locations across the southwestern U.S. The biologists then brought the rodents into captivity, fed them a diet of rabbit chow for one month and then resampled their microbiome. The results show that in both wild and captive individuals, evolutionary history was the biggest predictor of microbiome structure—more than diet and geography.

Microbiome stability and structure is governed by host phylogeny over diet and geography in woodrats (Neotoma spp.), Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2108787118.

https://phys.org/news/2021-11-woodrat-microbiomes.html?utm_source=n...

Part1

In wild populations, diet and geography did influence microbiome composition and diversity.

Diet contributed to natural microbiome structure. The authors collected feces from each rodent at the time of capture to get a snapshot of their diet. Using these samples, they found that animals with more diverse diets had more diverse microbiomes, and animals that fed on similar plants also showed similarities in their microbial communities.

Geography also played a role. The authors found that individuals at the same site had more similar microbiomes, and these communities became more dissimilar as animals were sampled at more distant locations.

However, host relatedness was still the most important factor predicting the microbial makeup of these wild mammals. And these effects only increased when animals were in captivity.

--

While every individual experienced a large shift, each individual's microbiome was still closer to its wild self than it would be to any other woodrat species. Researchers didn't see microbiomes merging into the same makeup; species retained distinct bacterial communities. With the differences of diet and habitat removed, they saw even more clearly the extent to which host relatedness influences microbiome structure.

The research team also found that microbiome responses to captivity were species specific, suggesting that host evolutionary history influences not only microbiome structure, but also stability.

Part 2

Prions may channel RNA's messages

Prions get mostly bad press, but they may be the keys to controlling protein synthesis in cells.

Prions, proteins that can misfold and aggregate, have been implicated in many neurodegenerative diseases. Yet some prions are involved in storing long term memories. New models by  scientists describe how they can regulate the translation of RNA messages into new proteins by forming organized protein synthesis factories.

Vectorial channeling as a mechanism for translational control by functional prions and condensates, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2115904118.

Booster shots 

Where does gold come from?—New insights into element synthesis in the universe

How are chemical elements produced in our Universe? Where do heavy elements like gold and uranium come from? Using computer simulations, a research team  shows that the synthesis of heavy elements is typical for certain black holes with orbiting matter accumulations, so-called accretion disks.

All heavy elements on Earth today were formed under extreme conditions in astrophysical environments: inside stars, in stellar explosions, and during the collision of neutron stars. Researchers are intrigued with the question in which of these astrophysical events the appropriate conditions for the formation of the heaviest elements, such as gold or uranium, exist. The spectacular first observation of gravitational waves and electromagnetic radiation originating from a neutron star merger in 2017 suggested that many heavy elements can be produced and released in these cosmic collisions. However, the question remains open as to when and why the material is ejected and whether there may be other scenarios in which heavy elements can be produced.

Promising candidates for heavy element production are black holes orbited by an accretion disk of dense and hot matter. Such a system is formed both after the merger of two massive neutron stars and during a so-called collapsar, the collapse and subsequent explosion of a rotating star.

Researchers systematically investigated for the first time the conversion rates of neutrons and protons for a large number of disk configurations by means of elaborate computer simulations, and we found that the disks are very rich in neutrons as long as certain conditions are met

Part 1

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Promising candidates for heavy element production are black holes orbited by an accretion disk of dense and hot matter. Such a system is formed both after the merger of two massive neutron stars and during a so-called collapsar, the collapse and subsequent explosion of a rotating star. The internal composition of such accretion disks has so far not been well understood, particularly with respect to the conditions under which an excess of neutrons forms. A high number of neutrons is a basic requirement for the synthesis of heavy elements, as it enables the rapid neutron-capture process or r-process. Nearly massless neutrinos play a key role in this process, as they enable conversion between protons and neutrons.

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The decisive factor is the total mass of the disk. The more massive the disk, the more often neutrons are formed from protons through capture of electrons under emission of neutrinos, and are available for the synthesis of heavy elements by means of the r-process. However, if the mass of the disk is too high, the inverse reaction plays an increased role so that more neutrinos are recaptured by neutrons before they leave the disk. These neutrons are then converted back to protons, which hinders the r-process." As the study shows, the optimal disk mass for prolific production of heavy elements is about 0.01 to 0.1 solar masses. The result provides strong evidence that neutron star mergers producing accretion disks with these exact masses could be the point of origin for a large fraction of the heavy elements. However, whether and how frequently such accretion disks occur in collapsar systems is currently unclear.

In addition to the possible processes of mass ejection, the research group led by Dr. Andreas Bauswein is also investigating the light signals generated by the ejected matter, which will be used to infer the mass and composition of the ejected matter in future observations of colliding neutron stars. An important building block for correctly reading these light signals is accurate knowledge of the masses and other properties of the newly formed elements.

O Just et al, Neutrino absorption and other physics dependencies in neutrino-cooled black hole accretion disks, Monthly Notices of the Royal Astronomical Society (2021). DOI: 10.1093/mnras/stab2861

https://phys.org/news/2021-11-gold-fromnew-insights-element-synthes...

New gene identified that contributes to progression to type 1 diabetes

When the pro-inflammatory pair, a receptor called CCR2 and its ligand CCL-2, get together, it increases the risk of developing type 1 diabetes, scientists report.

In this autoimmune disease that typically surfaces in childhood, the interaction of this natural lock and key recruits immune cells to the pancreas, which attack the insulin-producing islet cells, resulting in a lifelong course of insulin therapy and a lifelong increased risk of other health problems like heart and kidney disease.

The study, published in the Journal of Translational Autoimmunity, provides evidence the CCR2 gene promotes progression to type 1 as it provides new insight on how to delay disease progression.

The new study focused on 42 individuals who persistently had antibodies against the insulin-producing islet cells but never actually developed type 1, 48 who did develop type 1 and the remainder who did neither and served as the control group.

They found that blood levels of CCL-2, the ligand for CCR2, were lower in both individuals who had antibodies but not actual disease as well as those who progressed to type 1 diabetes.

They also found that both these groups have more of the receptors on their immune cells, which get recruited by the ligand to the six-inch organ in the abdomen that helps us break down the food we eat.

Conversely, less receptors mean less recruitment of immune cells, more normal levels of CCL-2 in the blood and less cell destruction.

Paul MH. Tran et al, The 3p21.31 genetic locus promotes progression to type 1 diabetes through the CCR2/CCL2 pathway, Journal of Translational Autoimmunity (2021). DOI: 10.1016/j.jtauto.2021.100127

https://medicalxpress.com/news/2021-11-gene-contributes-diabetes.ht...

Neuroscientists illuminate how brain cells 'navigate' in the light and dark

To navigate successfully in an environment, you need to continuously track the speed and direction of your head, even in the dark. Researchers have discovered how individual and networks of cells in an area of the brain called the retrosplenial cortex encode this angular head motion in mice to enable navigation both during the day and at night.

 One of the main aims of this study is to understand how the brain uses external and internal information to tell the difference between allocentric and egocentric-based motion. This paper is the first step in helping us understand whether individual cells  actually have access to both self-motion and, when available, the resultant external visual motion signals.

The researchers found that the retrosplenial cortex uses vestibular signals to encode the speed and direction of the head. However, when the lights are on, the coding of head motion is significantly more accurate.

When the lights are on, visual landmarks are available to better estimate your own speed (at which your head is moving). If you can't very reliably encode your head turning speed, then you very quickly lose your sense of direction. This might explain why, particularly in novel environments, we become much worse at navigating once the lights are turned out.

part 1

To understand how the brain enables navigation with and without visual cues, the researchers recorded from neurons across all layers in the retrosplenial cortex as the animals were free to roam around a large arena. This enabled the neuroscientists to identify neurons in the brain called angular head velocity (AHV) cells, which track the speed and direction of the head.

This work  showed that a single cell can see both kinds of signals: vestibular and visual. What was also critically important was the development of a behavioral task that enabled the scientists to determine that mice improve their estimation of their own head angular speed when a visual cue is present. It's pretty compelling that both the coding of head motion and the mouse's estimates of their motion speed both significantly improve when visual cues are available.

 Troy W Margrie, Multi-sensory coding of angular head velocity in the retrosplenial cortex, Neuron (2021). DOI: 10.1016/j.neuron.2021.10.031. www.cell.com/neuron/fulltext/S0896-6273(21)00846-1

https://medicalxpress.com/news/2021-11-neuroscientists-illuminate-b...

Killing bacteria with nanoparticles

Researchers  have developed a new technology based on nanoparticles to kill dangerous bacteria that hide inside human cells.

Burkholderia is a genus of bacterium that causes a deadly disease called melioidosis. This disease kills tens of thousands of people each year, particularly in southeast Asia. Antibiotics administered orally or intravenously often don't work very well against it as the bacteria hide away and grow in white blood cells called macrophages.

New research has shown that tiny capsules called polymersomes—which are about 1000th the diameter of a human hair—could be used to carry bug-killing antibiotics right to the site where the bacteria grow inside the cells. Their findings have been published in the journal ACS Nano.

Macrophages are cells of the immune system that have evolved to take up particles from the blood which is crucial to their role in preventing infection, but it also means that they can be exploited by some bacteria which infect and grow inside them.

In this study, the research team added polymersomes to macrophages which were infected with bacteria. Their results showed that the polymersomes were readily taken up by the macrophages and associated with the bacteria inside the cells. This means they could be an effective way to get a high concentration of antibiotics to the site of infection. The team hope this could eventually lead to patients being treated by injection or inhalation of antibiotic-laden capsules, saving many lives each year.

Eleanor Porges et al, Antibiotic-Loaded Polymersomes for Clearance of Intracellular Burkholderia thailandensis, ACS Nano (2021). DOI: 10.1021/acsnano.1c05309

https://phys.org/news/2021-11-bacteria-nanoparticles.html?utm_sourc...

Synthetic biology yields easy-to-use underwater adhesives

Several marine organisms, such as mussels, secrete adhesive proteins that allow them to stick to different surfaces under sea water. This attractive underwater adhesion property has inspired decades of research to create biomimetic glues for underwater repair or biological tissue repair. However, existing glues often do not have the desirable adhesion, are hard to use underwater, or are not biocompatible for medical applications. Now, there is a solution from synthetic biology.

Researchers  have developed a method that uses engineered microbes to produce the necessary ingredients for a biocompatible adhesive hydrogel that is as strong as spider silk and as adhesive as mussel foot protein (Mfp), which means it can stick to a myriad of surfaces underwater.

The team integrated the silk-amyloid protein with Mfp and, using a synthetic biology approach, synthesized a tri-hybrid protein that has the benefits of both the strong adhesion of Mfp and the high strength of spider silk. Using the tri-hybrid protein, they prepared adhesive hydrogels.

Because the protein-based adhesive can be biocompatible and biodegradable, the lab is particularly excited about its potential applications in tissue repair. This protein, they write in the paper, is particularly attractive for tendon-bone repair, which suffers from a high failure rate from current suture-based strategies.

Eugene Kim et al, A Biosynthetic Hybrid Spidroin-Amyloid-Mussel Foot Protein for Underwater Adhesion on Diverse Surfaces, ACS Applied Materials & Interfaces (2021). DOI: 10.1021/acsami.1c14182

https://phys.org/news/2021-11-synthetic-biology-yields-easy-to-use-...

A personalized exosuit for real-world walking

Does batting second in T20 world cup cricket offer a crucial advantage? A statistics professor explains

2021 ICC Men’s T20 World Cup, the tournament’s results: Of the 45 matches played at the tournament, 29 (around 64%) were won by the team batting second. Put another way, teams batting second won almost twice as many matches as teams batting first.

Some critics have gone as far as to suggest teams can “win on a coin toss” when deciding which side will bat first.

There are a range of suggested advantages to batting second, particularly in shorter forms of cricket. Perhaps chief among them is knowing exactly what score will win the game, and being able to plan the innings accordingly. As the afternoon or evening progresses, dew can also form on the ground, making it harder for bowlers to grip the ball and for fielders to retrieve it, and easier for batters to hit balls that “skid onto the bat” rather than changing direction.

But what do the stats actually say? Does the coin toss really confer a crucial advantage? 

Part 1

The first question to ask is whether the pattern of results seen during the world cup could have arisen purely by chance. We do this by using statistical tests to calculate the “p-value”, which tells us the probability of obtaining 29 or more “batting second” wins out of 45 matches if the true winning chance were 50-50.

In this case, we arrive at a “p-value” of around 0.04, or 4%. This probability is reasonably small, suggesting there is indeed some evidence that batting second was beneficial at this world cup, and that the pattern of results may not have arisen by chance.

But given our data set contains only 45 matches, our test does not have much statistical power, which means this evidence is far from overwhelming.

In other words, there is a non-negligible probability (4%) that this pattern of results arose by chance, and that batting second doesn’t confer a crucial advantage after all.

part 2

 analysis found that the timing of the match did not statistically influence the winning probability of the team batting second. In other words, the advantage of batting first or second did not depend on whether the match was staged during the afternoon or the evening.

That leaves two variables that might conceivably influence the situation: the venue hosting the match, and whether the team batting second has a higher or lower ranking than its opponent. That gives eight possible combinations (four venues times two possibilities for batting order) for which the statistical model can generate results.

Because there is just a handful of matches in each category, we can strengthen our statistical analysis using a concept called the “95% confidence interval”. Rather than generating only a single probability estimate, we can also calculate an upper and lower limit to our estimate, between which we can be 95% confident that the true probability is found.

Part 3

The results : The most striking result is the very high estimated probability of winning when batting second in Dubai (where Australia triumphed in the tournament’s final). Even when the batting-second team was ranked lower than its opponent, there still was a high estimated probability of victory.

The analysis revealed some evidence that it was beneficial to bat second in this world cup, but this is likely to depend greatly on the conditions. If we assume a match is played on a randomly selected pitch from the four venues used, and there is a 50% chance the higher-ranked team bats second, my model estimates the probability of winning when batting second is around 0.6, with a 95% confidence interval of 0.48 to 0.71.

So there is a likely benefit to batting second, but it’s far from a foregone conclusion.

https://theconversation.com/does-batting-second-in-t20-world-cup-cr...

Part 4

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Researchers find the finger snap to have the highest acceleration the human body produces

Snapping of fingers: Using an intermediate amount of friction, not too high and not too low, a snap of the finger produces the highest rotational accelerations observed in humans, even faster than the arm of a professional baseball pitcher. The results were published Nov. 17 in the Journal of the Royal Society Interface.

 In earlier work researc

hers had developed a general framework for explaining the surprisingly powerful and ultrafast motions observed in living organisms. The framework seemed to naturally apply to the snap. It posits that organisms depend on the use of a spring and latching mechanism to store up energy, which they can then quickly release.

Using high-speed imaging, automated image processing, and dynamic force sensors, the researchers analyzed a variety of finger snaps. They explored the role of friction by covering fingers with different materials, including metallic thimbles to simulate the effects of trying to snap while wearing a metallic gauntlet, much like Thanos.

For an ordinary snap with bare fingers, the researchers measured maximal rotational velocities of 7,800 degrees per second and rotational accelerations of 1.6 million degrees per second squared. The rotational velocity is less than that measured for the fastest rotational motions observed in humans, which come from the arms of professional baseball players during the act of pitching. However, the snap acceleration is the fastest human angular acceleration yet measured, almost three times faster than the rotational acceleration of a professional baseball pitcher's arm.

The finger snap occurs in only seven milliseconds, more than twenty times faster than the blink of an eye, which takes more than 150 milliseconds.

When the fingertips of the subjects were covered with metal thimbles, their maximal rotational velocities decreased dramatically, confirming the researchers' imaginations.

Reducing both the compressibility and friction of the skin by using things like metal armours make it a lot harder to build up enough force in your fingers to actually snap.

Surprisingly, increasing the friction of the fingertips with rubber coverings also reduce speed and acceleration. The researchers concluded that a Goldilocks zone of friction was necessary—too little friction and not enough energy was stored to power the snap, and too much friction led to energy dissipation as the fingers took longer to slide past each other, wasting the stored energy into heat.

The ultrafast snap of a finger is mediated by skin friction, Journal of the Royal Society Interface (2021). DOI: 10.1098/rsif.2021.0672. rsif.royalsocietypublishing.or … .1098/rsif.2021.0672

https://phys.org/news/2021-11-art-finger-snap-highest-human.html?ut...

Understanding how proteins are broken down in cells using advanced microscopes

How do organisms break down proteins when they are finished doing their job?

Protein degradation is a carefully orchestrated process. Proteins are marked for disposal with a molecular label called ubiquitin, and then fed into proteasomes, a kind of cellular paper shredder that chops up the proteins into small pieces. This process of ubiquitination, or labeling proteins with ubiquitin, is involved in a wide range of cellular processes, including cell division, DNA repair, and immune responses.

In a new study published in Nature on November 17, 2021, researchers used advanced electron microscopes to delve deeper into the process of protein degradation. They described the structure of a key enzyme that helps mediate ubiquitination in yeast, part of a cellular process called the N-degron pathway that may be responsible for determining the rate of degradation for up to 80% of equivalent proteins in humans. Malfunctions in this pathway can lead to accumulation of damaged or misfolded proteins, which underlies the aging process, neurodegeneration, and some rare autosomal recessive disorders, so understanding it better provides an opportunity to develop treatments.

Researchers were able to describe the structure of several intermediate enzyme complexes involved in the pathway, which will help researchers looking for ways to target proteins with drugs or intervene in a malfunctioning protein degradation process.

 Minglei Zhao, Structural insights into Ubr1-mediated N-degron polyubiquitination, Nature (2021). DOI: 10.1038/s41586-021-04097-8. www.nature.com/articles/s41586-021-04097-8

https://phys.org/news/2021-11-advanced-microscopes-scientists-cells...

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Using nematodes to sniff out cancer

 A screening test using tiny worms to detect early signs of pancreatic cancer in urine has been developed by a  biotech firm, which hopes it could help boost routine screening.

Scientists have long known that the bodily fluids of cancer patients smell different to those of healthy people, with dogs trained to detect the disease in breath or urine samples.

But Hirotsu Bio Science has genetically modified a type of worm called "C. elegans" -- around one millimetre long, with an acute sense of smell -- to react to the urine of people with pancreatic cancer, which is notoriously difficult to detect early.

The  firm has already used the worms to detect cancer in screening tests, though without specifying which type.

The new test is not meant to diagnose pancreatic cancer, but could help boost routine screening as urine samples can be collected at home without the need for a hospital visit.

 If the worms raise the alarm, the patient would then be referred to a doctor for further testing. In separate tests conducted by the firm, the worms correctly identified all 22 urine samples from pancreatic cancer patients, including people with early stages of the disease.

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0...

https://researchnews.cc/news/10038/What-a-worm--Japan-firm-uses-nem...

Seaweed-Like Device Generates Electricity Underwater

Energizer atoms: Physicists find new way to keep atoms excited

Researchers have tricked nature by tuning a dense quantum gas of atoms to make a congested "Fermi sea," thus keeping atoms in a high-energy state, or excited, for about 10% longer than usual by delaying their normal return to the lowest-energy state. The technique might be used to improve quantum communication networks and atomic clocks.

Quantum systems such as atoms that are excited above their resting state naturally calm down, or decay, by releasing light in quantized portions called photons. This common process is evident in the glow of fireflies and emission from LEDs. The rate of decay can be engineered by modifying the environment or the internal properties of the atoms. Previous research has modified the electromagnetic environment; the new work focuses on the atoms.

The new  method relies on a rule of the quantum world known as the Pauli exclusion principle, which says identical fermions (a category of particles) can't share the same quantum states at the same time. Therefore, if enough fermions are in a crowd—creating a Fermi sea—an excited fermion might not be able to fling out a photon as usual, because it would need to then recoil. That recoil could land it in the same quantum state of motion as one of its neighbors, which is forbidden due to a mechanism called Pauli blocking.

The blocking achievement is described in the Nov. 19 issue of Science. 

Pauli blocking uses well-organized quantum motional states of a Fermi sea to block the recoil of an atom that wants to decay, thus prohibiting spontaneous decay. It is a profound quantum effect for the control of matter's properties that was previously deemed unchangeable.

Christian Sanner et al, Pauli blocking of atom-light scattering, Science (2021). DOI: 10.1126/science.abh3483. www.science.org/doi/10.1126/science.abh3483

https://phys.org/news/2021-11-energizer-atoms-physicists.html?utm_s...

Host immunity drives viral evolution of dengue

New research by a team of investigators, provides evidence that host immunity drives evolution of the dengue virus. The work, published recently in Science, retrospectively analyzes two decades of dengue virus genetic variation from Thailand, alongside population-level measures of infection and immunity.

There are four types of dengue virus, and all four have co-circulated in Thailand since the early 1960s. This provides an opportunity to study how the viruses compete against each other for human hosts.

Dengue virus types are grouped according to how their surface proteins, or antigens, interact with infection-fighting antibodies in human blood. The four types, also called serotypes, are noted as DENV1 through DENV4. Although there is genetic variation between each dengue virus type, there is also variation within each dengue virus type.

Part 1

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The new study used 1,944 archival blood samples from Bangkok. The samples were preserved from people known to be ill with dengue and they represent all four dengue virus strains from every year between 1994 and 2014. The team genetically sequenced more than 2,000 virus samples.

The researchers then performed tests on a smaller subset of samples that represented a time series of each strain. From this, they then characterized the antigenic relationship of the strains to each other through time. Antigenic relationships characterize how well an immune response to one virus protects against other viruses.

Researchers  found that there is a pattern like influenza, where you get different viruses every year that are driven by natural selection for viruses that evade the human immune response to the population.  This work shown that that this is also happening with dengue.

The team used a process called antigenic cartography which makes a map to visualize the relatedness of viruses.

"When two viruses are close on that map, then that means immune responses 'sees' the viruses as similar," Katzelnick says. "For example, if you are infected with one virus, then an immune response to that virus would protect you against another virus that is nearby on the map."

The team found an overall pattern of dengue virus strains evolving away from each other over the 20-year study timeframe. While the serotypes at times oscillated closer, in general they grew further apart.

Part 2

the results also show a clear inverse relationship between the level of antigenic diversity in a given year and epidemic levels. When Thailand experienced large epidemic outbreaks, antigenic diversity was low. But in years when epidemic levels were lower than average, the antigenic diversity was higher.

"In general, it's been thought that if you get infected with one serotype of DENV then you are immune to that serotype for the rest of your life. But there have been observations where that seems to not be strictly true."

One explanation for re-infections is that dengue viruses may be subject to natural selective forces to evade the immune system of previously infected individuals. In essence, they must change just enough to avoid immune detection in a host where another serotype has already caused an infection.

These findings suggest that the dengue viruses are moving away from the viruses that generated immunity in the population in the past. It's sort of like the flu story, dengue is evolving to escape the immunity that is in the population at any particular time. But it seems to be happening at a slower pace with dengue than influenza.

Researchers already knew that there is a complex interplay between immunity and the dengue virus. When someone is exposed to a serotype of this virus, they will typically experience a mild infection that results in partial infection. But when they are exposed again, the partial immunity can trigger an overreaction that can lead to serious outcomes. The dengue virus appears, in these cases, to not only evade the immune response, but use it to its advantage to potentially increase its rate of growth.

Ninety to 95% of the people showing up at a hospital in Bangkok with dengue are having their second infection. "And most people who live their whole lives in Bangkok are getting infected multiple times."

This enhanced infection phenomenon may also contribute to the evolution of the pathogen, selecting for viruses that are similar enough to take advantage of the Immune response.

Overall, viruses were growing more different from each other over time, but scientists also observed that they grew closer together during some periods of time, particularly early in the time series. This indicates a tradeoff between evading immunity and taking advantage of partial immunity.

This paper is suggesting that the dengue viruses are changing and we need to update how we do surveillance to better understand immunity in populations and to ultimately reduce the number of people who get sick.

Leah Katzelnick et al, Antigenic evolution of dengue viruses over 20 years, Science (2021). DOI: 10.1126/science.abk0058. www.science.org/doi/10.1126/science.abk0058

https://phys.org/news/2021-11-host-immunity-viral-evolution-dengue....

Part 3

Cancer cells use 'tiny tentacles' to suppress the immune system

To grow and spread, cancer cells must evade the immune system. Investigators from Brigham and Women's Hospital and MIT used the power of nanotechnology to discover a new way that cancer can disarm its would-be cellular attackers by extending out nanoscale tentacles that can reach into an immune cell and pull out its powerpack. Slurping out the immune cell's mitochondria powers up the cancer cell and depletes the immune cell. The new findings, published in Nature Nanotechnology, could lead to new targets for developing the next generation of immunotherapy against cancer.

Cancer kills when the immune system is suppressed and cancer cells are able to metastasize, and it appears that nanotubes can help them do both. This is a completely new mechanism by which cancer cells evade the immune system and it gives us a new target to go after.

To investigate how cancer cells and immune cells interact at the nanoscale level, researchers set up experiments in which they co-cultured breast cancer cells and immune cells, such as T cells. Using field-emission scanning electron microscopy, they caught a glimpse of something unusual: Cancer cells and immune cells appeared to be physically connected by tiny tendrils, with widths mostly in the 100-1000 nanometer range. (For comparison, a human hair is approximately 80,000 to 100,000 nanometers). In some cases, the nanotubes came together to form thicker tubes. The team then stained mitochondria—which provide energy for cells—from the T cells with a fluorescent dye and watched as bright green mitochondria were pulled out of the immune cells, through the nanotubes, and into the cancer cells.

By carefully preserving the cell culture condition and observing intracellular structures, researchers saw these delicate nanotubes and they were stealing the immune cells' energy source. It was very exciting because this kind of behavior had never been observed before in cancer cells. The researchers then looked to see what would happen if they prevented the cancer cells from hijacking mitochondria. When they injected an inhibitor of nanotube formation into mouse models used for studying lung cancer and breast cancer, they saw a significant reduction in tumor growth.

Hae Jang, Intercellular nanotubes mediate mitochondrial trafficking between cancer and immune cells, Nature Nanotechnology (2021). DOI: 10.1038/s41565-021-01000-4. www.nature.com/articles/s41565-021-01000-4

https://phys.org/news/2021-11-cancer-cells-tiny-tentacles-suppress....

Warmer soil stores less carbon: study

Global warming will cause the world's soil to release carbon, new research shows.

Scientists used data on more than 9,000 soil samples from around the world, and found that carbon storage "declines strongly" as average temperatures increase.

This is an example of a "positive feedback", where global warming causes more carbon to be released into the atmosphere, further accelerating climate change.

Importantly, the amount of carbon that could be released depends on the soil type, with coarse-textured (low-clay) soils losing three times as much carbon as fine-textured (clay-rich) soils.

The researchers  say their findings help to identify vulnerable carbon stocks and provide an opportunity to improve Earth System Models (ESMs) that simulate future climate change.

Because there is more carbon stored in soils than there is in the atmosphere and all the trees on the planet combined, releasing even a small percentage could have a significant impact on our climate.

This analysis identified the carbon stores in coarse-textured soils at high-latitudes (far from the Equator) as likely to be the most vulnerable to climate change.

Such stores, therefore, may require particular attention given the high rates of warming taking place in cooler regions.

In contrast, researchers found carbon stores in fine-textured soils in tropical areas to be less vulnerable to climate warming.

By comparing carbon storage in places with different average temperatures, the researchers estimated the likely impact of global warming.

For every 10°C of increase in temperature, average carbon storage (across all soils) fell by more than 25%.

These results make it clear that, as temperatures rise, more and more carbon is release from soil.

The differences in carbon storage based on soil texture occur because finer soils provide more mineral surface area for carbon-based organic material to bond to, reducing the ability of microbes to access and decompose it.

Temperature effects on carbon storage are controlled by soil stabilisation capacities, Nature Communications (2021). DOI: 10.1038/s41467-021-27101-1

https://phys.org/news/2021-11-warmer-soil-carbon.html?utm_source=nw...